<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/home/sangenya/.cargo/registry/src/github.com-1ecc6299db9ec823/crossbeam-deque-0.8.1/src/deque.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>deque.rs - source</title><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../light.css" id="themeStyle"><link rel="stylesheet" type="text/css" href="../../dark.css" disabled ><link rel="stylesheet" type="text/css" href="../../ayu.css" disabled ><script id="default-settings"></script><script src="../../storage.js"></script><script src="../../crates.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="icon" type="image/svg+xml" href="../../favicon.svg">
<link rel="alternate icon" type="image/png" href="../../favicon-16x16.png">
<link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><style type="text/css">#crate-search{background-image:url("../../down-arrow.svg");}</style></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu" role="button">☰</div><a href='../../crossbeam_deque/index.html'><div class='logo-container rust-logo'><img src='../../rust-logo.png' alt='logo'></div></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!" aria-haspopup="menu" title="themes"><img src="../../brush.svg" width="18" height="18" alt="Pick another theme!"></button><div id="theme-choices" role="menu"></div></div><nav class="sub"><form class="search-form"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" disabled autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><button type="button" id="help-button" title="help">?</button><a id="settings-menu" href="../../settings.html" title="settings"><img src="../../wheel.svg" width="18" height="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><div class="example-wrap"><pre class="line-numbers"><span id="1"> 1</span>
<span id="2"> 2</span>
<span id="3"> 3</span>
<span id="4"> 4</span>
<span id="5"> 5</span>
<span id="6"> 6</span>
<span id="7"> 7</span>
<span id="8"> 8</span>
<span id="9"> 9</span>
<span id="10"> 10</span>
<span id="11"> 11</span>
<span id="12"> 12</span>
<span id="13"> 13</span>
<span id="14"> 14</span>
<span id="15"> 15</span>
<span id="16"> 16</span>
<span id="17"> 17</span>
<span id="18"> 18</span>
<span id="19"> 19</span>
<span id="20"> 20</span>
<span id="21"> 21</span>
<span id="22"> 22</span>
<span id="23"> 23</span>
<span id="24"> 24</span>
<span id="25"> 25</span>
<span id="26"> 26</span>
<span id="27"> 27</span>
<span id="28"> 28</span>
<span id="29"> 29</span>
<span id="30"> 30</span>
<span id="31"> 31</span>
<span id="32"> 32</span>
<span id="33"> 33</span>
<span id="34"> 34</span>
<span id="35"> 35</span>
<span id="36"> 36</span>
<span id="37"> 37</span>
<span id="38"> 38</span>
<span id="39"> 39</span>
<span id="40"> 40</span>
<span id="41"> 41</span>
<span id="42"> 42</span>
<span id="43"> 43</span>
<span id="44"> 44</span>
<span id="45"> 45</span>
<span id="46"> 46</span>
<span id="47"> 47</span>
<span id="48"> 48</span>
<span id="49"> 49</span>
<span id="50"> 50</span>
<span id="51"> 51</span>
<span id="52"> 52</span>
<span id="53"> 53</span>
<span id="54"> 54</span>
<span id="55"> 55</span>
<span id="56"> 56</span>
<span id="57"> 57</span>
<span id="58"> 58</span>
<span id="59"> 59</span>
<span id="60"> 60</span>
<span id="61"> 61</span>
<span id="62"> 62</span>
<span id="63"> 63</span>
<span id="64"> 64</span>
<span id="65"> 65</span>
<span id="66"> 66</span>
<span id="67"> 67</span>
<span id="68"> 68</span>
<span id="69"> 69</span>
<span id="70"> 70</span>
<span id="71"> 71</span>
<span id="72"> 72</span>
<span id="73"> 73</span>
<span id="74"> 74</span>
<span id="75"> 75</span>
<span id="76"> 76</span>
<span id="77"> 77</span>
<span id="78"> 78</span>
<span id="79"> 79</span>
<span id="80"> 80</span>
<span id="81"> 81</span>
<span id="82"> 82</span>
<span id="83"> 83</span>
<span id="84"> 84</span>
<span id="85"> 85</span>
<span id="86"> 86</span>
<span id="87"> 87</span>
<span id="88"> 88</span>
<span id="89"> 89</span>
<span id="90"> 90</span>
<span id="91"> 91</span>
<span id="92"> 92</span>
<span id="93"> 93</span>
<span id="94"> 94</span>
<span id="95"> 95</span>
<span id="96"> 96</span>
<span id="97"> 97</span>
<span id="98"> 98</span>
<span id="99"> 99</span>
<span id="100"> 100</span>
<span id="101"> 101</span>
<span id="102"> 102</span>
<span id="103"> 103</span>
<span id="104"> 104</span>
<span id="105"> 105</span>
<span id="106"> 106</span>
<span id="107"> 107</span>
<span id="108"> 108</span>
<span id="109"> 109</span>
<span id="110"> 110</span>
<span id="111"> 111</span>
<span id="112"> 112</span>
<span id="113"> 113</span>
<span id="114"> 114</span>
<span id="115"> 115</span>
<span id="116"> 116</span>
<span id="117"> 117</span>
<span id="118"> 118</span>
<span id="119"> 119</span>
<span id="120"> 120</span>
<span id="121"> 121</span>
<span id="122"> 122</span>
<span id="123"> 123</span>
<span id="124"> 124</span>
<span id="125"> 125</span>
<span id="126"> 126</span>
<span id="127"> 127</span>
<span id="128"> 128</span>
<span id="129"> 129</span>
<span id="130"> 130</span>
<span id="131"> 131</span>
<span id="132"> 132</span>
<span id="133"> 133</span>
<span id="134"> 134</span>
<span id="135"> 135</span>
<span id="136"> 136</span>
<span id="137"> 137</span>
<span id="138"> 138</span>
<span id="139"> 139</span>
<span id="140"> 140</span>
<span id="141"> 141</span>
<span id="142"> 142</span>
<span id="143"> 143</span>
<span id="144"> 144</span>
<span id="145"> 145</span>
<span id="146"> 146</span>
<span id="147"> 147</span>
<span id="148"> 148</span>
<span id="149"> 149</span>
<span id="150"> 150</span>
<span id="151"> 151</span>
<span id="152"> 152</span>
<span id="153"> 153</span>
<span id="154"> 154</span>
<span id="155"> 155</span>
<span id="156"> 156</span>
<span id="157"> 157</span>
<span id="158"> 158</span>
<span id="159"> 159</span>
<span id="160"> 160</span>
<span id="161"> 161</span>
<span id="162"> 162</span>
<span id="163"> 163</span>
<span id="164"> 164</span>
<span id="165"> 165</span>
<span id="166"> 166</span>
<span id="167"> 167</span>
<span id="168"> 168</span>
<span id="169"> 169</span>
<span id="170"> 170</span>
<span id="171"> 171</span>
<span id="172"> 172</span>
<span id="173"> 173</span>
<span id="174"> 174</span>
<span id="175"> 175</span>
<span id="176"> 176</span>
<span id="177"> 177</span>
<span id="178"> 178</span>
<span id="179"> 179</span>
<span id="180"> 180</span>
<span id="181"> 181</span>
<span id="182"> 182</span>
<span id="183"> 183</span>
<span id="184"> 184</span>
<span id="185"> 185</span>
<span id="186"> 186</span>
<span id="187"> 187</span>
<span id="188"> 188</span>
<span id="189"> 189</span>
<span id="190"> 190</span>
<span id="191"> 191</span>
<span id="192"> 192</span>
<span id="193"> 193</span>
<span id="194"> 194</span>
<span id="195"> 195</span>
<span id="196"> 196</span>
<span id="197"> 197</span>
<span id="198"> 198</span>
<span id="199"> 199</span>
<span id="200"> 200</span>
<span id="201"> 201</span>
<span id="202"> 202</span>
<span id="203"> 203</span>
<span id="204"> 204</span>
<span id="205"> 205</span>
<span id="206"> 206</span>
<span id="207"> 207</span>
<span id="208"> 208</span>
<span id="209"> 209</span>
<span id="210"> 210</span>
<span id="211"> 211</span>
<span id="212"> 212</span>
<span id="213"> 213</span>
<span id="214"> 214</span>
<span id="215"> 215</span>
<span id="216"> 216</span>
<span id="217"> 217</span>
<span id="218"> 218</span>
<span id="219"> 219</span>
<span id="220"> 220</span>
<span id="221"> 221</span>
<span id="222"> 222</span>
<span id="223"> 223</span>
<span id="224"> 224</span>
<span id="225"> 225</span>
<span id="226"> 226</span>
<span id="227"> 227</span>
<span id="228"> 228</span>
<span id="229"> 229</span>
<span id="230"> 230</span>
<span id="231"> 231</span>
<span id="232"> 232</span>
<span id="233"> 233</span>
<span id="234"> 234</span>
<span id="235"> 235</span>
<span id="236"> 236</span>
<span id="237"> 237</span>
<span id="238"> 238</span>
<span id="239"> 239</span>
<span id="240"> 240</span>
<span id="241"> 241</span>
<span id="242"> 242</span>
<span id="243"> 243</span>
<span id="244"> 244</span>
<span id="245"> 245</span>
<span id="246"> 246</span>
<span id="247"> 247</span>
<span id="248"> 248</span>
<span id="249"> 249</span>
<span id="250"> 250</span>
<span id="251"> 251</span>
<span id="252"> 252</span>
<span id="253"> 253</span>
<span id="254"> 254</span>
<span id="255"> 255</span>
<span id="256"> 256</span>
<span id="257"> 257</span>
<span id="258"> 258</span>
<span id="259"> 259</span>
<span id="260"> 260</span>
<span id="261"> 261</span>
<span id="262"> 262</span>
<span id="263"> 263</span>
<span id="264"> 264</span>
<span id="265"> 265</span>
<span id="266"> 266</span>
<span id="267"> 267</span>
<span id="268"> 268</span>
<span id="269"> 269</span>
<span id="270"> 270</span>
<span id="271"> 271</span>
<span id="272"> 272</span>
<span id="273"> 273</span>
<span id="274"> 274</span>
<span id="275"> 275</span>
<span id="276"> 276</span>
<span id="277"> 277</span>
<span id="278"> 278</span>
<span id="279"> 279</span>
<span id="280"> 280</span>
<span id="281"> 281</span>
<span id="282"> 282</span>
<span id="283"> 283</span>
<span id="284"> 284</span>
<span id="285"> 285</span>
<span id="286"> 286</span>
<span id="287"> 287</span>
<span id="288"> 288</span>
<span id="289"> 289</span>
<span id="290"> 290</span>
<span id="291"> 291</span>
<span id="292"> 292</span>
<span id="293"> 293</span>
<span id="294"> 294</span>
<span id="295"> 295</span>
<span id="296"> 296</span>
<span id="297"> 297</span>
<span id="298"> 298</span>
<span id="299"> 299</span>
<span id="300"> 300</span>
<span id="301"> 301</span>
<span id="302"> 302</span>
<span id="303"> 303</span>
<span id="304"> 304</span>
<span id="305"> 305</span>
<span id="306"> 306</span>
<span id="307"> 307</span>
<span id="308"> 308</span>
<span id="309"> 309</span>
<span id="310"> 310</span>
<span id="311"> 311</span>
<span id="312"> 312</span>
<span id="313"> 313</span>
<span id="314"> 314</span>
<span id="315"> 315</span>
<span id="316"> 316</span>
<span id="317"> 317</span>
<span id="318"> 318</span>
<span id="319"> 319</span>
<span id="320"> 320</span>
<span id="321"> 321</span>
<span id="322"> 322</span>
<span id="323"> 323</span>
<span id="324"> 324</span>
<span id="325"> 325</span>
<span id="326"> 326</span>
<span id="327"> 327</span>
<span id="328"> 328</span>
<span id="329"> 329</span>
<span id="330"> 330</span>
<span id="331"> 331</span>
<span id="332"> 332</span>
<span id="333"> 333</span>
<span id="334"> 334</span>
<span id="335"> 335</span>
<span id="336"> 336</span>
<span id="337"> 337</span>
<span id="338"> 338</span>
<span id="339"> 339</span>
<span id="340"> 340</span>
<span id="341"> 341</span>
<span id="342"> 342</span>
<span id="343"> 343</span>
<span id="344"> 344</span>
<span id="345"> 345</span>
<span id="346"> 346</span>
<span id="347"> 347</span>
<span id="348"> 348</span>
<span id="349"> 349</span>
<span id="350"> 350</span>
<span id="351"> 351</span>
<span id="352"> 352</span>
<span id="353"> 353</span>
<span id="354"> 354</span>
<span id="355"> 355</span>
<span id="356"> 356</span>
<span id="357"> 357</span>
<span id="358"> 358</span>
<span id="359"> 359</span>
<span id="360"> 360</span>
<span id="361"> 361</span>
<span id="362"> 362</span>
<span id="363"> 363</span>
<span id="364"> 364</span>
<span id="365"> 365</span>
<span id="366"> 366</span>
<span id="367"> 367</span>
<span id="368"> 368</span>
<span id="369"> 369</span>
<span id="370"> 370</span>
<span id="371"> 371</span>
<span id="372"> 372</span>
<span id="373"> 373</span>
<span id="374"> 374</span>
<span id="375"> 375</span>
<span id="376"> 376</span>
<span id="377"> 377</span>
<span id="378"> 378</span>
<span id="379"> 379</span>
<span id="380"> 380</span>
<span id="381"> 381</span>
<span id="382"> 382</span>
<span id="383"> 383</span>
<span id="384"> 384</span>
<span id="385"> 385</span>
<span id="386"> 386</span>
<span id="387"> 387</span>
<span id="388"> 388</span>
<span id="389"> 389</span>
<span id="390"> 390</span>
<span id="391"> 391</span>
<span id="392"> 392</span>
<span id="393"> 393</span>
<span id="394"> 394</span>
<span id="395"> 395</span>
<span id="396"> 396</span>
<span id="397"> 397</span>
<span id="398"> 398</span>
<span id="399"> 399</span>
<span id="400"> 400</span>
<span id="401"> 401</span>
<span id="402"> 402</span>
<span id="403"> 403</span>
<span id="404"> 404</span>
<span id="405"> 405</span>
<span id="406"> 406</span>
<span id="407"> 407</span>
<span id="408"> 408</span>
<span id="409"> 409</span>
<span id="410"> 410</span>
<span id="411"> 411</span>
<span id="412"> 412</span>
<span id="413"> 413</span>
<span id="414"> 414</span>
<span id="415"> 415</span>
<span id="416"> 416</span>
<span id="417"> 417</span>
<span id="418"> 418</span>
<span id="419"> 419</span>
<span id="420"> 420</span>
<span id="421"> 421</span>
<span id="422"> 422</span>
<span id="423"> 423</span>
<span id="424"> 424</span>
<span id="425"> 425</span>
<span id="426"> 426</span>
<span id="427"> 427</span>
<span id="428"> 428</span>
<span id="429"> 429</span>
<span id="430"> 430</span>
<span id="431"> 431</span>
<span id="432"> 432</span>
<span id="433"> 433</span>
<span id="434"> 434</span>
<span id="435"> 435</span>
<span id="436"> 436</span>
<span id="437"> 437</span>
<span id="438"> 438</span>
<span id="439"> 439</span>
<span id="440"> 440</span>
<span id="441"> 441</span>
<span id="442"> 442</span>
<span id="443"> 443</span>
<span id="444"> 444</span>
<span id="445"> 445</span>
<span id="446"> 446</span>
<span id="447"> 447</span>
<span id="448"> 448</span>
<span id="449"> 449</span>
<span id="450"> 450</span>
<span id="451"> 451</span>
<span id="452"> 452</span>
<span id="453"> 453</span>
<span id="454"> 454</span>
<span id="455"> 455</span>
<span id="456"> 456</span>
<span id="457"> 457</span>
<span id="458"> 458</span>
<span id="459"> 459</span>
<span id="460"> 460</span>
<span id="461"> 461</span>
<span id="462"> 462</span>
<span id="463"> 463</span>
<span id="464"> 464</span>
<span id="465"> 465</span>
<span id="466"> 466</span>
<span id="467"> 467</span>
<span id="468"> 468</span>
<span id="469"> 469</span>
<span id="470"> 470</span>
<span id="471"> 471</span>
<span id="472"> 472</span>
<span id="473"> 473</span>
<span id="474"> 474</span>
<span id="475"> 475</span>
<span id="476"> 476</span>
<span id="477"> 477</span>
<span id="478"> 478</span>
<span id="479"> 479</span>
<span id="480"> 480</span>
<span id="481"> 481</span>
<span id="482"> 482</span>
<span id="483"> 483</span>
<span id="484"> 484</span>
<span id="485"> 485</span>
<span id="486"> 486</span>
<span id="487"> 487</span>
<span id="488"> 488</span>
<span id="489"> 489</span>
<span id="490"> 490</span>
<span id="491"> 491</span>
<span id="492"> 492</span>
<span id="493"> 493</span>
<span id="494"> 494</span>
<span id="495"> 495</span>
<span id="496"> 496</span>
<span id="497"> 497</span>
<span id="498"> 498</span>
<span id="499"> 499</span>
<span id="500"> 500</span>
<span id="501"> 501</span>
<span id="502"> 502</span>
<span id="503"> 503</span>
<span id="504"> 504</span>
<span id="505"> 505</span>
<span id="506"> 506</span>
<span id="507"> 507</span>
<span id="508"> 508</span>
<span id="509"> 509</span>
<span id="510"> 510</span>
<span id="511"> 511</span>
<span id="512"> 512</span>
<span id="513"> 513</span>
<span id="514"> 514</span>
<span id="515"> 515</span>
<span id="516"> 516</span>
<span id="517"> 517</span>
<span id="518"> 518</span>
<span id="519"> 519</span>
<span id="520"> 520</span>
<span id="521"> 521</span>
<span id="522"> 522</span>
<span id="523"> 523</span>
<span id="524"> 524</span>
<span id="525"> 525</span>
<span id="526"> 526</span>
<span id="527"> 527</span>
<span id="528"> 528</span>
<span id="529"> 529</span>
<span id="530"> 530</span>
<span id="531"> 531</span>
<span id="532"> 532</span>
<span id="533"> 533</span>
<span id="534"> 534</span>
<span id="535"> 535</span>
<span id="536"> 536</span>
<span id="537"> 537</span>
<span id="538"> 538</span>
<span id="539"> 539</span>
<span id="540"> 540</span>
<span id="541"> 541</span>
<span id="542"> 542</span>
<span id="543"> 543</span>
<span id="544"> 544</span>
<span id="545"> 545</span>
<span id="546"> 546</span>
<span id="547"> 547</span>
<span id="548"> 548</span>
<span id="549"> 549</span>
<span id="550"> 550</span>
<span id="551"> 551</span>
<span id="552"> 552</span>
<span id="553"> 553</span>
<span id="554"> 554</span>
<span id="555"> 555</span>
<span id="556"> 556</span>
<span id="557"> 557</span>
<span id="558"> 558</span>
<span id="559"> 559</span>
<span id="560"> 560</span>
<span id="561"> 561</span>
<span id="562"> 562</span>
<span id="563"> 563</span>
<span id="564"> 564</span>
<span id="565"> 565</span>
<span id="566"> 566</span>
<span id="567"> 567</span>
<span id="568"> 568</span>
<span id="569"> 569</span>
<span id="570"> 570</span>
<span id="571"> 571</span>
<span id="572"> 572</span>
<span id="573"> 573</span>
<span id="574"> 574</span>
<span id="575"> 575</span>
<span id="576"> 576</span>
<span id="577"> 577</span>
<span id="578"> 578</span>
<span id="579"> 579</span>
<span id="580"> 580</span>
<span id="581"> 581</span>
<span id="582"> 582</span>
<span id="583"> 583</span>
<span id="584"> 584</span>
<span id="585"> 585</span>
<span id="586"> 586</span>
<span id="587"> 587</span>
<span id="588"> 588</span>
<span id="589"> 589</span>
<span id="590"> 590</span>
<span id="591"> 591</span>
<span id="592"> 592</span>
<span id="593"> 593</span>
<span id="594"> 594</span>
<span id="595"> 595</span>
<span id="596"> 596</span>
<span id="597"> 597</span>
<span id="598"> 598</span>
<span id="599"> 599</span>
<span id="600"> 600</span>
<span id="601"> 601</span>
<span id="602"> 602</span>
<span id="603"> 603</span>
<span id="604"> 604</span>
<span id="605"> 605</span>
<span id="606"> 606</span>
<span id="607"> 607</span>
<span id="608"> 608</span>
<span id="609"> 609</span>
<span id="610"> 610</span>
<span id="611"> 611</span>
<span id="612"> 612</span>
<span id="613"> 613</span>
<span id="614"> 614</span>
<span id="615"> 615</span>
<span id="616"> 616</span>
<span id="617"> 617</span>
<span id="618"> 618</span>
<span id="619"> 619</span>
<span id="620"> 620</span>
<span id="621"> 621</span>
<span id="622"> 622</span>
<span id="623"> 623</span>
<span id="624"> 624</span>
<span id="625"> 625</span>
<span id="626"> 626</span>
<span id="627"> 627</span>
<span id="628"> 628</span>
<span id="629"> 629</span>
<span id="630"> 630</span>
<span id="631"> 631</span>
<span id="632"> 632</span>
<span id="633"> 633</span>
<span id="634"> 634</span>
<span id="635"> 635</span>
<span id="636"> 636</span>
<span id="637"> 637</span>
<span id="638"> 638</span>
<span id="639"> 639</span>
<span id="640"> 640</span>
<span id="641"> 641</span>
<span id="642"> 642</span>
<span id="643"> 643</span>
<span id="644"> 644</span>
<span id="645"> 645</span>
<span id="646"> 646</span>
<span id="647"> 647</span>
<span id="648"> 648</span>
<span id="649"> 649</span>
<span id="650"> 650</span>
<span id="651"> 651</span>
<span id="652"> 652</span>
<span id="653"> 653</span>
<span id="654"> 654</span>
<span id="655"> 655</span>
<span id="656"> 656</span>
<span id="657"> 657</span>
<span id="658"> 658</span>
<span id="659"> 659</span>
<span id="660"> 660</span>
<span id="661"> 661</span>
<span id="662"> 662</span>
<span id="663"> 663</span>
<span id="664"> 664</span>
<span id="665"> 665</span>
<span id="666"> 666</span>
<span id="667"> 667</span>
<span id="668"> 668</span>
<span id="669"> 669</span>
<span id="670"> 670</span>
<span id="671"> 671</span>
<span id="672"> 672</span>
<span id="673"> 673</span>
<span id="674"> 674</span>
<span id="675"> 675</span>
<span id="676"> 676</span>
<span id="677"> 677</span>
<span id="678"> 678</span>
<span id="679"> 679</span>
<span id="680"> 680</span>
<span id="681"> 681</span>
<span id="682"> 682</span>
<span id="683"> 683</span>
<span id="684"> 684</span>
<span id="685"> 685</span>
<span id="686"> 686</span>
<span id="687"> 687</span>
<span id="688"> 688</span>
<span id="689"> 689</span>
<span id="690"> 690</span>
<span id="691"> 691</span>
<span id="692"> 692</span>
<span id="693"> 693</span>
<span id="694"> 694</span>
<span id="695"> 695</span>
<span id="696"> 696</span>
<span id="697"> 697</span>
<span id="698"> 698</span>
<span id="699"> 699</span>
<span id="700"> 700</span>
<span id="701"> 701</span>
<span id="702"> 702</span>
<span id="703"> 703</span>
<span id="704"> 704</span>
<span id="705"> 705</span>
<span id="706"> 706</span>
<span id="707"> 707</span>
<span id="708"> 708</span>
<span id="709"> 709</span>
<span id="710"> 710</span>
<span id="711"> 711</span>
<span id="712"> 712</span>
<span id="713"> 713</span>
<span id="714"> 714</span>
<span id="715"> 715</span>
<span id="716"> 716</span>
<span id="717"> 717</span>
<span id="718"> 718</span>
<span id="719"> 719</span>
<span id="720"> 720</span>
<span id="721"> 721</span>
<span id="722"> 722</span>
<span id="723"> 723</span>
<span id="724"> 724</span>
<span id="725"> 725</span>
<span id="726"> 726</span>
<span id="727"> 727</span>
<span id="728"> 728</span>
<span id="729"> 729</span>
<span id="730"> 730</span>
<span id="731"> 731</span>
<span id="732"> 732</span>
<span id="733"> 733</span>
<span id="734"> 734</span>
<span id="735"> 735</span>
<span id="736"> 736</span>
<span id="737"> 737</span>
<span id="738"> 738</span>
<span id="739"> 739</span>
<span id="740"> 740</span>
<span id="741"> 741</span>
<span id="742"> 742</span>
<span id="743"> 743</span>
<span id="744"> 744</span>
<span id="745"> 745</span>
<span id="746"> 746</span>
<span id="747"> 747</span>
<span id="748"> 748</span>
<span id="749"> 749</span>
<span id="750"> 750</span>
<span id="751"> 751</span>
<span id="752"> 752</span>
<span id="753"> 753</span>
<span id="754"> 754</span>
<span id="755"> 755</span>
<span id="756"> 756</span>
<span id="757"> 757</span>
<span id="758"> 758</span>
<span id="759"> 759</span>
<span id="760"> 760</span>
<span id="761"> 761</span>
<span id="762"> 762</span>
<span id="763"> 763</span>
<span id="764"> 764</span>
<span id="765"> 765</span>
<span id="766"> 766</span>
<span id="767"> 767</span>
<span id="768"> 768</span>
<span id="769"> 769</span>
<span id="770"> 770</span>
<span id="771"> 771</span>
<span id="772"> 772</span>
<span id="773"> 773</span>
<span id="774"> 774</span>
<span id="775"> 775</span>
<span id="776"> 776</span>
<span id="777"> 777</span>
<span id="778"> 778</span>
<span id="779"> 779</span>
<span id="780"> 780</span>
<span id="781"> 781</span>
<span id="782"> 782</span>
<span id="783"> 783</span>
<span id="784"> 784</span>
<span id="785"> 785</span>
<span id="786"> 786</span>
<span id="787"> 787</span>
<span id="788"> 788</span>
<span id="789"> 789</span>
<span id="790"> 790</span>
<span id="791"> 791</span>
<span id="792"> 792</span>
<span id="793"> 793</span>
<span id="794"> 794</span>
<span id="795"> 795</span>
<span id="796"> 796</span>
<span id="797"> 797</span>
<span id="798"> 798</span>
<span id="799"> 799</span>
<span id="800"> 800</span>
<span id="801"> 801</span>
<span id="802"> 802</span>
<span id="803"> 803</span>
<span id="804"> 804</span>
<span id="805"> 805</span>
<span id="806"> 806</span>
<span id="807"> 807</span>
<span id="808"> 808</span>
<span id="809"> 809</span>
<span id="810"> 810</span>
<span id="811"> 811</span>
<span id="812"> 812</span>
<span id="813"> 813</span>
<span id="814"> 814</span>
<span id="815"> 815</span>
<span id="816"> 816</span>
<span id="817"> 817</span>
<span id="818"> 818</span>
<span id="819"> 819</span>
<span id="820"> 820</span>
<span id="821"> 821</span>
<span id="822"> 822</span>
<span id="823"> 823</span>
<span id="824"> 824</span>
<span id="825"> 825</span>
<span id="826"> 826</span>
<span id="827"> 827</span>
<span id="828"> 828</span>
<span id="829"> 829</span>
<span id="830"> 830</span>
<span id="831"> 831</span>
<span id="832"> 832</span>
<span id="833"> 833</span>
<span id="834"> 834</span>
<span id="835"> 835</span>
<span id="836"> 836</span>
<span id="837"> 837</span>
<span id="838"> 838</span>
<span id="839"> 839</span>
<span id="840"> 840</span>
<span id="841"> 841</span>
<span id="842"> 842</span>
<span id="843"> 843</span>
<span id="844"> 844</span>
<span id="845"> 845</span>
<span id="846"> 846</span>
<span id="847"> 847</span>
<span id="848"> 848</span>
<span id="849"> 849</span>
<span id="850"> 850</span>
<span id="851"> 851</span>
<span id="852"> 852</span>
<span id="853"> 853</span>
<span id="854"> 854</span>
<span id="855"> 855</span>
<span id="856"> 856</span>
<span id="857"> 857</span>
<span id="858"> 858</span>
<span id="859"> 859</span>
<span id="860"> 860</span>
<span id="861"> 861</span>
<span id="862"> 862</span>
<span id="863"> 863</span>
<span id="864"> 864</span>
<span id="865"> 865</span>
<span id="866"> 866</span>
<span id="867"> 867</span>
<span id="868"> 868</span>
<span id="869"> 869</span>
<span id="870"> 870</span>
<span id="871"> 871</span>
<span id="872"> 872</span>
<span id="873"> 873</span>
<span id="874"> 874</span>
<span id="875"> 875</span>
<span id="876"> 876</span>
<span id="877"> 877</span>
<span id="878"> 878</span>
<span id="879"> 879</span>
<span id="880"> 880</span>
<span id="881"> 881</span>
<span id="882"> 882</span>
<span id="883"> 883</span>
<span id="884"> 884</span>
<span id="885"> 885</span>
<span id="886"> 886</span>
<span id="887"> 887</span>
<span id="888"> 888</span>
<span id="889"> 889</span>
<span id="890"> 890</span>
<span id="891"> 891</span>
<span id="892"> 892</span>
<span id="893"> 893</span>
<span id="894"> 894</span>
<span id="895"> 895</span>
<span id="896"> 896</span>
<span id="897"> 897</span>
<span id="898"> 898</span>
<span id="899"> 899</span>
<span id="900"> 900</span>
<span id="901"> 901</span>
<span id="902"> 902</span>
<span id="903"> 903</span>
<span id="904"> 904</span>
<span id="905"> 905</span>
<span id="906"> 906</span>
<span id="907"> 907</span>
<span id="908"> 908</span>
<span id="909"> 909</span>
<span id="910"> 910</span>
<span id="911"> 911</span>
<span id="912"> 912</span>
<span id="913"> 913</span>
<span id="914"> 914</span>
<span id="915"> 915</span>
<span id="916"> 916</span>
<span id="917"> 917</span>
<span id="918"> 918</span>
<span id="919"> 919</span>
<span id="920"> 920</span>
<span id="921"> 921</span>
<span id="922"> 922</span>
<span id="923"> 923</span>
<span id="924"> 924</span>
<span id="925"> 925</span>
<span id="926"> 926</span>
<span id="927"> 927</span>
<span id="928"> 928</span>
<span id="929"> 929</span>
<span id="930"> 930</span>
<span id="931"> 931</span>
<span id="932"> 932</span>
<span id="933"> 933</span>
<span id="934"> 934</span>
<span id="935"> 935</span>
<span id="936"> 936</span>
<span id="937"> 937</span>
<span id="938"> 938</span>
<span id="939"> 939</span>
<span id="940"> 940</span>
<span id="941"> 941</span>
<span id="942"> 942</span>
<span id="943"> 943</span>
<span id="944"> 944</span>
<span id="945"> 945</span>
<span id="946"> 946</span>
<span id="947"> 947</span>
<span id="948"> 948</span>
<span id="949"> 949</span>
<span id="950"> 950</span>
<span id="951"> 951</span>
<span id="952"> 952</span>
<span id="953"> 953</span>
<span id="954"> 954</span>
<span id="955"> 955</span>
<span id="956"> 956</span>
<span id="957"> 957</span>
<span id="958"> 958</span>
<span id="959"> 959</span>
<span id="960"> 960</span>
<span id="961"> 961</span>
<span id="962"> 962</span>
<span id="963"> 963</span>
<span id="964"> 964</span>
<span id="965"> 965</span>
<span id="966"> 966</span>
<span id="967"> 967</span>
<span id="968"> 968</span>
<span id="969"> 969</span>
<span id="970"> 970</span>
<span id="971"> 971</span>
<span id="972"> 972</span>
<span id="973"> 973</span>
<span id="974"> 974</span>
<span id="975"> 975</span>
<span id="976"> 976</span>
<span id="977"> 977</span>
<span id="978"> 978</span>
<span id="979"> 979</span>
<span id="980"> 980</span>
<span id="981"> 981</span>
<span id="982"> 982</span>
<span id="983"> 983</span>
<span id="984"> 984</span>
<span id="985"> 985</span>
<span id="986"> 986</span>
<span id="987"> 987</span>
<span id="988"> 988</span>
<span id="989"> 989</span>
<span id="990"> 990</span>
<span id="991"> 991</span>
<span id="992"> 992</span>
<span id="993"> 993</span>
<span id="994"> 994</span>
<span id="995"> 995</span>
<span id="996"> 996</span>
<span id="997"> 997</span>
<span id="998"> 998</span>
<span id="999"> 999</span>
<span id="1000">1000</span>
<span id="1001">1001</span>
<span id="1002">1002</span>
<span id="1003">1003</span>
<span id="1004">1004</span>
<span id="1005">1005</span>
<span id="1006">1006</span>
<span id="1007">1007</span>
<span id="1008">1008</span>
<span id="1009">1009</span>
<span id="1010">1010</span>
<span id="1011">1011</span>
<span id="1012">1012</span>
<span id="1013">1013</span>
<span id="1014">1014</span>
<span id="1015">1015</span>
<span id="1016">1016</span>
<span id="1017">1017</span>
<span id="1018">1018</span>
<span id="1019">1019</span>
<span id="1020">1020</span>
<span id="1021">1021</span>
<span id="1022">1022</span>
<span id="1023">1023</span>
<span id="1024">1024</span>
<span id="1025">1025</span>
<span id="1026">1026</span>
<span id="1027">1027</span>
<span id="1028">1028</span>
<span id="1029">1029</span>
<span id="1030">1030</span>
<span id="1031">1031</span>
<span id="1032">1032</span>
<span id="1033">1033</span>
<span id="1034">1034</span>
<span id="1035">1035</span>
<span id="1036">1036</span>
<span id="1037">1037</span>
<span id="1038">1038</span>
<span id="1039">1039</span>
<span id="1040">1040</span>
<span id="1041">1041</span>
<span id="1042">1042</span>
<span id="1043">1043</span>
<span id="1044">1044</span>
<span id="1045">1045</span>
<span id="1046">1046</span>
<span id="1047">1047</span>
<span id="1048">1048</span>
<span id="1049">1049</span>
<span id="1050">1050</span>
<span id="1051">1051</span>
<span id="1052">1052</span>
<span id="1053">1053</span>
<span id="1054">1054</span>
<span id="1055">1055</span>
<span id="1056">1056</span>
<span id="1057">1057</span>
<span id="1058">1058</span>
<span id="1059">1059</span>
<span id="1060">1060</span>
<span id="1061">1061</span>
<span id="1062">1062</span>
<span id="1063">1063</span>
<span id="1064">1064</span>
<span id="1065">1065</span>
<span id="1066">1066</span>
<span id="1067">1067</span>
<span id="1068">1068</span>
<span id="1069">1069</span>
<span id="1070">1070</span>
<span id="1071">1071</span>
<span id="1072">1072</span>
<span id="1073">1073</span>
<span id="1074">1074</span>
<span id="1075">1075</span>
<span id="1076">1076</span>
<span id="1077">1077</span>
<span id="1078">1078</span>
<span id="1079">1079</span>
<span id="1080">1080</span>
<span id="1081">1081</span>
<span id="1082">1082</span>
<span id="1083">1083</span>
<span id="1084">1084</span>
<span id="1085">1085</span>
<span id="1086">1086</span>
<span id="1087">1087</span>
<span id="1088">1088</span>
<span id="1089">1089</span>
<span id="1090">1090</span>
<span id="1091">1091</span>
<span id="1092">1092</span>
<span id="1093">1093</span>
<span id="1094">1094</span>
<span id="1095">1095</span>
<span id="1096">1096</span>
<span id="1097">1097</span>
<span id="1098">1098</span>
<span id="1099">1099</span>
<span id="1100">1100</span>
<span id="1101">1101</span>
<span id="1102">1102</span>
<span id="1103">1103</span>
<span id="1104">1104</span>
<span id="1105">1105</span>
<span id="1106">1106</span>
<span id="1107">1107</span>
<span id="1108">1108</span>
<span id="1109">1109</span>
<span id="1110">1110</span>
<span id="1111">1111</span>
<span id="1112">1112</span>
<span id="1113">1113</span>
<span id="1114">1114</span>
<span id="1115">1115</span>
<span id="1116">1116</span>
<span id="1117">1117</span>
<span id="1118">1118</span>
<span id="1119">1119</span>
<span id="1120">1120</span>
<span id="1121">1121</span>
<span id="1122">1122</span>
<span id="1123">1123</span>
<span id="1124">1124</span>
<span id="1125">1125</span>
<span id="1126">1126</span>
<span id="1127">1127</span>
<span id="1128">1128</span>
<span id="1129">1129</span>
<span id="1130">1130</span>
<span id="1131">1131</span>
<span id="1132">1132</span>
<span id="1133">1133</span>
<span id="1134">1134</span>
<span id="1135">1135</span>
<span id="1136">1136</span>
<span id="1137">1137</span>
<span id="1138">1138</span>
<span id="1139">1139</span>
<span id="1140">1140</span>
<span id="1141">1141</span>
<span id="1142">1142</span>
<span id="1143">1143</span>
<span id="1144">1144</span>
<span id="1145">1145</span>
<span id="1146">1146</span>
<span id="1147">1147</span>
<span id="1148">1148</span>
<span id="1149">1149</span>
<span id="1150">1150</span>
<span id="1151">1151</span>
<span id="1152">1152</span>
<span id="1153">1153</span>
<span id="1154">1154</span>
<span id="1155">1155</span>
<span id="1156">1156</span>
<span id="1157">1157</span>
<span id="1158">1158</span>
<span id="1159">1159</span>
<span id="1160">1160</span>
<span id="1161">1161</span>
<span id="1162">1162</span>
<span id="1163">1163</span>
<span id="1164">1164</span>
<span id="1165">1165</span>
<span id="1166">1166</span>
<span id="1167">1167</span>
<span id="1168">1168</span>
<span id="1169">1169</span>
<span id="1170">1170</span>
<span id="1171">1171</span>
<span id="1172">1172</span>
<span id="1173">1173</span>
<span id="1174">1174</span>
<span id="1175">1175</span>
<span id="1176">1176</span>
<span id="1177">1177</span>
<span id="1178">1178</span>
<span id="1179">1179</span>
<span id="1180">1180</span>
<span id="1181">1181</span>
<span id="1182">1182</span>
<span id="1183">1183</span>
<span id="1184">1184</span>
<span id="1185">1185</span>
<span id="1186">1186</span>
<span id="1187">1187</span>
<span id="1188">1188</span>
<span id="1189">1189</span>
<span id="1190">1190</span>
<span id="1191">1191</span>
<span id="1192">1192</span>
<span id="1193">1193</span>
<span id="1194">1194</span>
<span id="1195">1195</span>
<span id="1196">1196</span>
<span id="1197">1197</span>
<span id="1198">1198</span>
<span id="1199">1199</span>
<span id="1200">1200</span>
<span id="1201">1201</span>
<span id="1202">1202</span>
<span id="1203">1203</span>
<span id="1204">1204</span>
<span id="1205">1205</span>
<span id="1206">1206</span>
<span id="1207">1207</span>
<span id="1208">1208</span>
<span id="1209">1209</span>
<span id="1210">1210</span>
<span id="1211">1211</span>
<span id="1212">1212</span>
<span id="1213">1213</span>
<span id="1214">1214</span>
<span id="1215">1215</span>
<span id="1216">1216</span>
<span id="1217">1217</span>
<span id="1218">1218</span>
<span id="1219">1219</span>
<span id="1220">1220</span>
<span id="1221">1221</span>
<span id="1222">1222</span>
<span id="1223">1223</span>
<span id="1224">1224</span>
<span id="1225">1225</span>
<span id="1226">1226</span>
<span id="1227">1227</span>
<span id="1228">1228</span>
<span id="1229">1229</span>
<span id="1230">1230</span>
<span id="1231">1231</span>
<span id="1232">1232</span>
<span id="1233">1233</span>
<span id="1234">1234</span>
<span id="1235">1235</span>
<span id="1236">1236</span>
<span id="1237">1237</span>
<span id="1238">1238</span>
<span id="1239">1239</span>
<span id="1240">1240</span>
<span id="1241">1241</span>
<span id="1242">1242</span>
<span id="1243">1243</span>
<span id="1244">1244</span>
<span id="1245">1245</span>
<span id="1246">1246</span>
<span id="1247">1247</span>
<span id="1248">1248</span>
<span id="1249">1249</span>
<span id="1250">1250</span>
<span id="1251">1251</span>
<span id="1252">1252</span>
<span id="1253">1253</span>
<span id="1254">1254</span>
<span id="1255">1255</span>
<span id="1256">1256</span>
<span id="1257">1257</span>
<span id="1258">1258</span>
<span id="1259">1259</span>
<span id="1260">1260</span>
<span id="1261">1261</span>
<span id="1262">1262</span>
<span id="1263">1263</span>
<span id="1264">1264</span>
<span id="1265">1265</span>
<span id="1266">1266</span>
<span id="1267">1267</span>
<span id="1268">1268</span>
<span id="1269">1269</span>
<span id="1270">1270</span>
<span id="1271">1271</span>
<span id="1272">1272</span>
<span id="1273">1273</span>
<span id="1274">1274</span>
<span id="1275">1275</span>
<span id="1276">1276</span>
<span id="1277">1277</span>
<span id="1278">1278</span>
<span id="1279">1279</span>
<span id="1280">1280</span>
<span id="1281">1281</span>
<span id="1282">1282</span>
<span id="1283">1283</span>
<span id="1284">1284</span>
<span id="1285">1285</span>
<span id="1286">1286</span>
<span id="1287">1287</span>
<span id="1288">1288</span>
<span id="1289">1289</span>
<span id="1290">1290</span>
<span id="1291">1291</span>
<span id="1292">1292</span>
<span id="1293">1293</span>
<span id="1294">1294</span>
<span id="1295">1295</span>
<span id="1296">1296</span>
<span id="1297">1297</span>
<span id="1298">1298</span>
<span id="1299">1299</span>
<span id="1300">1300</span>
<span id="1301">1301</span>
<span id="1302">1302</span>
<span id="1303">1303</span>
<span id="1304">1304</span>
<span id="1305">1305</span>
<span id="1306">1306</span>
<span id="1307">1307</span>
<span id="1308">1308</span>
<span id="1309">1309</span>
<span id="1310">1310</span>
<span id="1311">1311</span>
<span id="1312">1312</span>
<span id="1313">1313</span>
<span id="1314">1314</span>
<span id="1315">1315</span>
<span id="1316">1316</span>
<span id="1317">1317</span>
<span id="1318">1318</span>
<span id="1319">1319</span>
<span id="1320">1320</span>
<span id="1321">1321</span>
<span id="1322">1322</span>
<span id="1323">1323</span>
<span id="1324">1324</span>
<span id="1325">1325</span>
<span id="1326">1326</span>
<span id="1327">1327</span>
<span id="1328">1328</span>
<span id="1329">1329</span>
<span id="1330">1330</span>
<span id="1331">1331</span>
<span id="1332">1332</span>
<span id="1333">1333</span>
<span id="1334">1334</span>
<span id="1335">1335</span>
<span id="1336">1336</span>
<span id="1337">1337</span>
<span id="1338">1338</span>
<span id="1339">1339</span>
<span id="1340">1340</span>
<span id="1341">1341</span>
<span id="1342">1342</span>
<span id="1343">1343</span>
<span id="1344">1344</span>
<span id="1345">1345</span>
<span id="1346">1346</span>
<span id="1347">1347</span>
<span id="1348">1348</span>
<span id="1349">1349</span>
<span id="1350">1350</span>
<span id="1351">1351</span>
<span id="1352">1352</span>
<span id="1353">1353</span>
<span id="1354">1354</span>
<span id="1355">1355</span>
<span id="1356">1356</span>
<span id="1357">1357</span>
<span id="1358">1358</span>
<span id="1359">1359</span>
<span id="1360">1360</span>
<span id="1361">1361</span>
<span id="1362">1362</span>
<span id="1363">1363</span>
<span id="1364">1364</span>
<span id="1365">1365</span>
<span id="1366">1366</span>
<span id="1367">1367</span>
<span id="1368">1368</span>
<span id="1369">1369</span>
<span id="1370">1370</span>
<span id="1371">1371</span>
<span id="1372">1372</span>
<span id="1373">1373</span>
<span id="1374">1374</span>
<span id="1375">1375</span>
<span id="1376">1376</span>
<span id="1377">1377</span>
<span id="1378">1378</span>
<span id="1379">1379</span>
<span id="1380">1380</span>
<span id="1381">1381</span>
<span id="1382">1382</span>
<span id="1383">1383</span>
<span id="1384">1384</span>
<span id="1385">1385</span>
<span id="1386">1386</span>
<span id="1387">1387</span>
<span id="1388">1388</span>
<span id="1389">1389</span>
<span id="1390">1390</span>
<span id="1391">1391</span>
<span id="1392">1392</span>
<span id="1393">1393</span>
<span id="1394">1394</span>
<span id="1395">1395</span>
<span id="1396">1396</span>
<span id="1397">1397</span>
<span id="1398">1398</span>
<span id="1399">1399</span>
<span id="1400">1400</span>
<span id="1401">1401</span>
<span id="1402">1402</span>
<span id="1403">1403</span>
<span id="1404">1404</span>
<span id="1405">1405</span>
<span id="1406">1406</span>
<span id="1407">1407</span>
<span id="1408">1408</span>
<span id="1409">1409</span>
<span id="1410">1410</span>
<span id="1411">1411</span>
<span id="1412">1412</span>
<span id="1413">1413</span>
<span id="1414">1414</span>
<span id="1415">1415</span>
<span id="1416">1416</span>
<span id="1417">1417</span>
<span id="1418">1418</span>
<span id="1419">1419</span>
<span id="1420">1420</span>
<span id="1421">1421</span>
<span id="1422">1422</span>
<span id="1423">1423</span>
<span id="1424">1424</span>
<span id="1425">1425</span>
<span id="1426">1426</span>
<span id="1427">1427</span>
<span id="1428">1428</span>
<span id="1429">1429</span>
<span id="1430">1430</span>
<span id="1431">1431</span>
<span id="1432">1432</span>
<span id="1433">1433</span>
<span id="1434">1434</span>
<span id="1435">1435</span>
<span id="1436">1436</span>
<span id="1437">1437</span>
<span id="1438">1438</span>
<span id="1439">1439</span>
<span id="1440">1440</span>
<span id="1441">1441</span>
<span id="1442">1442</span>
<span id="1443">1443</span>
<span id="1444">1444</span>
<span id="1445">1445</span>
<span id="1446">1446</span>
<span id="1447">1447</span>
<span id="1448">1448</span>
<span id="1449">1449</span>
<span id="1450">1450</span>
<span id="1451">1451</span>
<span id="1452">1452</span>
<span id="1453">1453</span>
<span id="1454">1454</span>
<span id="1455">1455</span>
<span id="1456">1456</span>
<span id="1457">1457</span>
<span id="1458">1458</span>
<span id="1459">1459</span>
<span id="1460">1460</span>
<span id="1461">1461</span>
<span id="1462">1462</span>
<span id="1463">1463</span>
<span id="1464">1464</span>
<span id="1465">1465</span>
<span id="1466">1466</span>
<span id="1467">1467</span>
<span id="1468">1468</span>
<span id="1469">1469</span>
<span id="1470">1470</span>
<span id="1471">1471</span>
<span id="1472">1472</span>
<span id="1473">1473</span>
<span id="1474">1474</span>
<span id="1475">1475</span>
<span id="1476">1476</span>
<span id="1477">1477</span>
<span id="1478">1478</span>
<span id="1479">1479</span>
<span id="1480">1480</span>
<span id="1481">1481</span>
<span id="1482">1482</span>
<span id="1483">1483</span>
<span id="1484">1484</span>
<span id="1485">1485</span>
<span id="1486">1486</span>
<span id="1487">1487</span>
<span id="1488">1488</span>
<span id="1489">1489</span>
<span id="1490">1490</span>
<span id="1491">1491</span>
<span id="1492">1492</span>
<span id="1493">1493</span>
<span id="1494">1494</span>
<span id="1495">1495</span>
<span id="1496">1496</span>
<span id="1497">1497</span>
<span id="1498">1498</span>
<span id="1499">1499</span>
<span id="1500">1500</span>
<span id="1501">1501</span>
<span id="1502">1502</span>
<span id="1503">1503</span>
<span id="1504">1504</span>
<span id="1505">1505</span>
<span id="1506">1506</span>
<span id="1507">1507</span>
<span id="1508">1508</span>
<span id="1509">1509</span>
<span id="1510">1510</span>
<span id="1511">1511</span>
<span id="1512">1512</span>
<span id="1513">1513</span>
<span id="1514">1514</span>
<span id="1515">1515</span>
<span id="1516">1516</span>
<span id="1517">1517</span>
<span id="1518">1518</span>
<span id="1519">1519</span>
<span id="1520">1520</span>
<span id="1521">1521</span>
<span id="1522">1522</span>
<span id="1523">1523</span>
<span id="1524">1524</span>
<span id="1525">1525</span>
<span id="1526">1526</span>
<span id="1527">1527</span>
<span id="1528">1528</span>
<span id="1529">1529</span>
<span id="1530">1530</span>
<span id="1531">1531</span>
<span id="1532">1532</span>
<span id="1533">1533</span>
<span id="1534">1534</span>
<span id="1535">1535</span>
<span id="1536">1536</span>
<span id="1537">1537</span>
<span id="1538">1538</span>
<span id="1539">1539</span>
<span id="1540">1540</span>
<span id="1541">1541</span>
<span id="1542">1542</span>
<span id="1543">1543</span>
<span id="1544">1544</span>
<span id="1545">1545</span>
<span id="1546">1546</span>
<span id="1547">1547</span>
<span id="1548">1548</span>
<span id="1549">1549</span>
<span id="1550">1550</span>
<span id="1551">1551</span>
<span id="1552">1552</span>
<span id="1553">1553</span>
<span id="1554">1554</span>
<span id="1555">1555</span>
<span id="1556">1556</span>
<span id="1557">1557</span>
<span id="1558">1558</span>
<span id="1559">1559</span>
<span id="1560">1560</span>
<span id="1561">1561</span>
<span id="1562">1562</span>
<span id="1563">1563</span>
<span id="1564">1564</span>
<span id="1565">1565</span>
<span id="1566">1566</span>
<span id="1567">1567</span>
<span id="1568">1568</span>
<span id="1569">1569</span>
<span id="1570">1570</span>
<span id="1571">1571</span>
<span id="1572">1572</span>
<span id="1573">1573</span>
<span id="1574">1574</span>
<span id="1575">1575</span>
<span id="1576">1576</span>
<span id="1577">1577</span>
<span id="1578">1578</span>
<span id="1579">1579</span>
<span id="1580">1580</span>
<span id="1581">1581</span>
<span id="1582">1582</span>
<span id="1583">1583</span>
<span id="1584">1584</span>
<span id="1585">1585</span>
<span id="1586">1586</span>
<span id="1587">1587</span>
<span id="1588">1588</span>
<span id="1589">1589</span>
<span id="1590">1590</span>
<span id="1591">1591</span>
<span id="1592">1592</span>
<span id="1593">1593</span>
<span id="1594">1594</span>
<span id="1595">1595</span>
<span id="1596">1596</span>
<span id="1597">1597</span>
<span id="1598">1598</span>
<span id="1599">1599</span>
<span id="1600">1600</span>
<span id="1601">1601</span>
<span id="1602">1602</span>
<span id="1603">1603</span>
<span id="1604">1604</span>
<span id="1605">1605</span>
<span id="1606">1606</span>
<span id="1607">1607</span>
<span id="1608">1608</span>
<span id="1609">1609</span>
<span id="1610">1610</span>
<span id="1611">1611</span>
<span id="1612">1612</span>
<span id="1613">1613</span>
<span id="1614">1614</span>
<span id="1615">1615</span>
<span id="1616">1616</span>
<span id="1617">1617</span>
<span id="1618">1618</span>
<span id="1619">1619</span>
<span id="1620">1620</span>
<span id="1621">1621</span>
<span id="1622">1622</span>
<span id="1623">1623</span>
<span id="1624">1624</span>
<span id="1625">1625</span>
<span id="1626">1626</span>
<span id="1627">1627</span>
<span id="1628">1628</span>
<span id="1629">1629</span>
<span id="1630">1630</span>
<span id="1631">1631</span>
<span id="1632">1632</span>
<span id="1633">1633</span>
<span id="1634">1634</span>
<span id="1635">1635</span>
<span id="1636">1636</span>
<span id="1637">1637</span>
<span id="1638">1638</span>
<span id="1639">1639</span>
<span id="1640">1640</span>
<span id="1641">1641</span>
<span id="1642">1642</span>
<span id="1643">1643</span>
<span id="1644">1644</span>
<span id="1645">1645</span>
<span id="1646">1646</span>
<span id="1647">1647</span>
<span id="1648">1648</span>
<span id="1649">1649</span>
<span id="1650">1650</span>
<span id="1651">1651</span>
<span id="1652">1652</span>
<span id="1653">1653</span>
<span id="1654">1654</span>
<span id="1655">1655</span>
<span id="1656">1656</span>
<span id="1657">1657</span>
<span id="1658">1658</span>
<span id="1659">1659</span>
<span id="1660">1660</span>
<span id="1661">1661</span>
<span id="1662">1662</span>
<span id="1663">1663</span>
<span id="1664">1664</span>
<span id="1665">1665</span>
<span id="1666">1666</span>
<span id="1667">1667</span>
<span id="1668">1668</span>
<span id="1669">1669</span>
<span id="1670">1670</span>
<span id="1671">1671</span>
<span id="1672">1672</span>
<span id="1673">1673</span>
<span id="1674">1674</span>
<span id="1675">1675</span>
<span id="1676">1676</span>
<span id="1677">1677</span>
<span id="1678">1678</span>
<span id="1679">1679</span>
<span id="1680">1680</span>
<span id="1681">1681</span>
<span id="1682">1682</span>
<span id="1683">1683</span>
<span id="1684">1684</span>
<span id="1685">1685</span>
<span id="1686">1686</span>
<span id="1687">1687</span>
<span id="1688">1688</span>
<span id="1689">1689</span>
<span id="1690">1690</span>
<span id="1691">1691</span>
<span id="1692">1692</span>
<span id="1693">1693</span>
<span id="1694">1694</span>
<span id="1695">1695</span>
<span id="1696">1696</span>
<span id="1697">1697</span>
<span id="1698">1698</span>
<span id="1699">1699</span>
<span id="1700">1700</span>
<span id="1701">1701</span>
<span id="1702">1702</span>
<span id="1703">1703</span>
<span id="1704">1704</span>
<span id="1705">1705</span>
<span id="1706">1706</span>
<span id="1707">1707</span>
<span id="1708">1708</span>
<span id="1709">1709</span>
<span id="1710">1710</span>
<span id="1711">1711</span>
<span id="1712">1712</span>
<span id="1713">1713</span>
<span id="1714">1714</span>
<span id="1715">1715</span>
<span id="1716">1716</span>
<span id="1717">1717</span>
<span id="1718">1718</span>
<span id="1719">1719</span>
<span id="1720">1720</span>
<span id="1721">1721</span>
<span id="1722">1722</span>
<span id="1723">1723</span>
<span id="1724">1724</span>
<span id="1725">1725</span>
<span id="1726">1726</span>
<span id="1727">1727</span>
<span id="1728">1728</span>
<span id="1729">1729</span>
<span id="1730">1730</span>
<span id="1731">1731</span>
<span id="1732">1732</span>
<span id="1733">1733</span>
<span id="1734">1734</span>
<span id="1735">1735</span>
<span id="1736">1736</span>
<span id="1737">1737</span>
<span id="1738">1738</span>
<span id="1739">1739</span>
<span id="1740">1740</span>
<span id="1741">1741</span>
<span id="1742">1742</span>
<span id="1743">1743</span>
<span id="1744">1744</span>
<span id="1745">1745</span>
<span id="1746">1746</span>
<span id="1747">1747</span>
<span id="1748">1748</span>
<span id="1749">1749</span>
<span id="1750">1750</span>
<span id="1751">1751</span>
<span id="1752">1752</span>
<span id="1753">1753</span>
<span id="1754">1754</span>
<span id="1755">1755</span>
<span id="1756">1756</span>
<span id="1757">1757</span>
<span id="1758">1758</span>
<span id="1759">1759</span>
<span id="1760">1760</span>
<span id="1761">1761</span>
<span id="1762">1762</span>
<span id="1763">1763</span>
<span id="1764">1764</span>
<span id="1765">1765</span>
<span id="1766">1766</span>
<span id="1767">1767</span>
<span id="1768">1768</span>
<span id="1769">1769</span>
<span id="1770">1770</span>
<span id="1771">1771</span>
<span id="1772">1772</span>
<span id="1773">1773</span>
<span id="1774">1774</span>
<span id="1775">1775</span>
<span id="1776">1776</span>
<span id="1777">1777</span>
<span id="1778">1778</span>
<span id="1779">1779</span>
<span id="1780">1780</span>
<span id="1781">1781</span>
<span id="1782">1782</span>
<span id="1783">1783</span>
<span id="1784">1784</span>
<span id="1785">1785</span>
<span id="1786">1786</span>
<span id="1787">1787</span>
<span id="1788">1788</span>
<span id="1789">1789</span>
<span id="1790">1790</span>
<span id="1791">1791</span>
<span id="1792">1792</span>
<span id="1793">1793</span>
<span id="1794">1794</span>
<span id="1795">1795</span>
<span id="1796">1796</span>
<span id="1797">1797</span>
<span id="1798">1798</span>
<span id="1799">1799</span>
<span id="1800">1800</span>
<span id="1801">1801</span>
<span id="1802">1802</span>
<span id="1803">1803</span>
<span id="1804">1804</span>
<span id="1805">1805</span>
<span id="1806">1806</span>
<span id="1807">1807</span>
<span id="1808">1808</span>
<span id="1809">1809</span>
<span id="1810">1810</span>
<span id="1811">1811</span>
<span id="1812">1812</span>
<span id="1813">1813</span>
<span id="1814">1814</span>
<span id="1815">1815</span>
<span id="1816">1816</span>
<span id="1817">1817</span>
<span id="1818">1818</span>
<span id="1819">1819</span>
<span id="1820">1820</span>
<span id="1821">1821</span>
<span id="1822">1822</span>
<span id="1823">1823</span>
<span id="1824">1824</span>
<span id="1825">1825</span>
<span id="1826">1826</span>
<span id="1827">1827</span>
<span id="1828">1828</span>
<span id="1829">1829</span>
<span id="1830">1830</span>
<span id="1831">1831</span>
<span id="1832">1832</span>
<span id="1833">1833</span>
<span id="1834">1834</span>
<span id="1835">1835</span>
<span id="1836">1836</span>
<span id="1837">1837</span>
<span id="1838">1838</span>
<span id="1839">1839</span>
<span id="1840">1840</span>
<span id="1841">1841</span>
<span id="1842">1842</span>
<span id="1843">1843</span>
<span id="1844">1844</span>
<span id="1845">1845</span>
<span id="1846">1846</span>
<span id="1847">1847</span>
<span id="1848">1848</span>
<span id="1849">1849</span>
<span id="1850">1850</span>
<span id="1851">1851</span>
<span id="1852">1852</span>
<span id="1853">1853</span>
<span id="1854">1854</span>
<span id="1855">1855</span>
<span id="1856">1856</span>
<span id="1857">1857</span>
<span id="1858">1858</span>
<span id="1859">1859</span>
<span id="1860">1860</span>
<span id="1861">1861</span>
<span id="1862">1862</span>
<span id="1863">1863</span>
<span id="1864">1864</span>
<span id="1865">1865</span>
<span id="1866">1866</span>
<span id="1867">1867</span>
<span id="1868">1868</span>
<span id="1869">1869</span>
<span id="1870">1870</span>
<span id="1871">1871</span>
<span id="1872">1872</span>
<span id="1873">1873</span>
<span id="1874">1874</span>
<span id="1875">1875</span>
<span id="1876">1876</span>
<span id="1877">1877</span>
<span id="1878">1878</span>
<span id="1879">1879</span>
<span id="1880">1880</span>
<span id="1881">1881</span>
<span id="1882">1882</span>
<span id="1883">1883</span>
<span id="1884">1884</span>
<span id="1885">1885</span>
<span id="1886">1886</span>
<span id="1887">1887</span>
<span id="1888">1888</span>
<span id="1889">1889</span>
<span id="1890">1890</span>
<span id="1891">1891</span>
<span id="1892">1892</span>
<span id="1893">1893</span>
<span id="1894">1894</span>
<span id="1895">1895</span>
<span id="1896">1896</span>
<span id="1897">1897</span>
<span id="1898">1898</span>
<span id="1899">1899</span>
<span id="1900">1900</span>
<span id="1901">1901</span>
<span id="1902">1902</span>
<span id="1903">1903</span>
<span id="1904">1904</span>
<span id="1905">1905</span>
<span id="1906">1906</span>
<span id="1907">1907</span>
<span id="1908">1908</span>
<span id="1909">1909</span>
<span id="1910">1910</span>
<span id="1911">1911</span>
<span id="1912">1912</span>
<span id="1913">1913</span>
<span id="1914">1914</span>
<span id="1915">1915</span>
<span id="1916">1916</span>
<span id="1917">1917</span>
<span id="1918">1918</span>
<span id="1919">1919</span>
<span id="1920">1920</span>
<span id="1921">1921</span>
<span id="1922">1922</span>
<span id="1923">1923</span>
<span id="1924">1924</span>
<span id="1925">1925</span>
<span id="1926">1926</span>
<span id="1927">1927</span>
<span id="1928">1928</span>
<span id="1929">1929</span>
<span id="1930">1930</span>
<span id="1931">1931</span>
<span id="1932">1932</span>
<span id="1933">1933</span>
<span id="1934">1934</span>
<span id="1935">1935</span>
<span id="1936">1936</span>
<span id="1937">1937</span>
<span id="1938">1938</span>
<span id="1939">1939</span>
<span id="1940">1940</span>
<span id="1941">1941</span>
<span id="1942">1942</span>
<span id="1943">1943</span>
<span id="1944">1944</span>
<span id="1945">1945</span>
<span id="1946">1946</span>
<span id="1947">1947</span>
<span id="1948">1948</span>
<span id="1949">1949</span>
<span id="1950">1950</span>
<span id="1951">1951</span>
<span id="1952">1952</span>
<span id="1953">1953</span>
<span id="1954">1954</span>
<span id="1955">1955</span>
<span id="1956">1956</span>
<span id="1957">1957</span>
<span id="1958">1958</span>
<span id="1959">1959</span>
<span id="1960">1960</span>
<span id="1961">1961</span>
<span id="1962">1962</span>
<span id="1963">1963</span>
<span id="1964">1964</span>
<span id="1965">1965</span>
<span id="1966">1966</span>
<span id="1967">1967</span>
<span id="1968">1968</span>
<span id="1969">1969</span>
<span id="1970">1970</span>
<span id="1971">1971</span>
<span id="1972">1972</span>
<span id="1973">1973</span>
<span id="1974">1974</span>
<span id="1975">1975</span>
<span id="1976">1976</span>
<span id="1977">1977</span>
<span id="1978">1978</span>
<span id="1979">1979</span>
<span id="1980">1980</span>
<span id="1981">1981</span>
<span id="1982">1982</span>
<span id="1983">1983</span>
<span id="1984">1984</span>
<span id="1985">1985</span>
<span id="1986">1986</span>
<span id="1987">1987</span>
<span id="1988">1988</span>
<span id="1989">1989</span>
<span id="1990">1990</span>
<span id="1991">1991</span>
<span id="1992">1992</span>
<span id="1993">1993</span>
<span id="1994">1994</span>
<span id="1995">1995</span>
<span id="1996">1996</span>
<span id="1997">1997</span>
<span id="1998">1998</span>
<span id="1999">1999</span>
<span id="2000">2000</span>
<span id="2001">2001</span>
<span id="2002">2002</span>
<span id="2003">2003</span>
<span id="2004">2004</span>
<span id="2005">2005</span>
<span id="2006">2006</span>
<span id="2007">2007</span>
<span id="2008">2008</span>
<span id="2009">2009</span>
<span id="2010">2010</span>
<span id="2011">2011</span>
<span id="2012">2012</span>
<span id="2013">2013</span>
<span id="2014">2014</span>
<span id="2015">2015</span>
<span id="2016">2016</span>
<span id="2017">2017</span>
<span id="2018">2018</span>
<span id="2019">2019</span>
<span id="2020">2020</span>
<span id="2021">2021</span>
<span id="2022">2022</span>
<span id="2023">2023</span>
<span id="2024">2024</span>
<span id="2025">2025</span>
<span id="2026">2026</span>
<span id="2027">2027</span>
<span id="2028">2028</span>
<span id="2029">2029</span>
<span id="2030">2030</span>
<span id="2031">2031</span>
<span id="2032">2032</span>
<span id="2033">2033</span>
<span id="2034">2034</span>
<span id="2035">2035</span>
<span id="2036">2036</span>
<span id="2037">2037</span>
<span id="2038">2038</span>
<span id="2039">2039</span>
<span id="2040">2040</span>
<span id="2041">2041</span>
<span id="2042">2042</span>
<span id="2043">2043</span>
<span id="2044">2044</span>
</pre><pre class="rust">
<span class="kw">use</span> <span class="ident">std::cell</span>::{<span class="ident">Cell</span>, <span class="ident">UnsafeCell</span>};
<span class="kw">use</span> <span class="ident">std::cmp</span>;
<span class="kw">use</span> <span class="ident">std::fmt</span>;
<span class="kw">use</span> <span class="ident">std::iter::FromIterator</span>;
<span class="kw">use</span> <span class="ident">std::marker::PhantomData</span>;
<span class="kw">use</span> <span class="ident">std::mem</span>::{<span class="self">self</span>, <span class="ident">MaybeUninit</span>};
<span class="kw">use</span> <span class="ident">std::ptr</span>;
<span class="kw">use</span> <span class="ident">std::sync::atomic</span>::{<span class="self">self</span>, <span class="ident">AtomicIsize</span>, <span class="ident">AtomicPtr</span>, <span class="ident">AtomicUsize</span>, <span class="ident">Ordering</span>};
<span class="kw">use</span> <span class="ident">std::sync::Arc</span>;
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::epoch</span>::{<span class="self">self</span>, <span class="ident">Atomic</span>, <span class="ident">Owned</span>};
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::utils</span>::{<span class="ident">Backoff</span>, <span class="ident">CachePadded</span>};
<span class="comment">// Minimum buffer capacity.</span>
<span class="kw">const</span> <span class="ident">MIN_CAP</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">64</span>;
<span class="comment">// Maximum number of tasks that can be stolen in `steal_batch()` and `steal_batch_and_pop()`.</span>
<span class="kw">const</span> <span class="ident">MAX_BATCH</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">32</span>;
<span class="comment">// If a buffer of at least this size is retired, thread-local garbage is flushed so that it gets</span>
<span class="comment">// deallocated as soon as possible.</span>
<span class="kw">const</span> <span class="ident">FLUSH_THRESHOLD_BYTES</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">10</span>;
<span class="doccomment">/// A buffer that holds tasks in a worker queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is just a pointer to the buffer and its length - dropping an instance of this struct will</span>
<span class="doccomment">/// *not* deallocate the buffer.</span>
<span class="kw">struct</span> <span class="ident">Buffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Pointer to the allocated memory.</span>
<span class="ident">ptr</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">T</span>,
<span class="doccomment">/// Capacity of the buffer. Always a power of two.</span>
<span class="ident">cap</span>: <span class="ident">usize</span>,
}
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Send</span> <span class="kw">for</span> <span class="ident">Buffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Buffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Allocates a new buffer with the specified capacity.</span>
<span class="kw">fn</span> <span class="ident">alloc</span>(<span class="ident">cap</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Buffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="macro">debug_assert_eq!</span>(<span class="ident">cap</span>, <span class="ident">cap</span>.<span class="ident">next_power_of_two</span>());
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">v</span> <span class="op">=</span> <span class="ident">Vec::with_capacity</span>(<span class="ident">cap</span>);
<span class="kw">let</span> <span class="ident">ptr</span> <span class="op">=</span> <span class="ident">v</span>.<span class="ident">as_mut_ptr</span>();
<span class="ident">mem::forget</span>(<span class="ident">v</span>);
<span class="ident">Buffer</span> { <span class="ident">ptr</span>, <span class="ident">cap</span> }
}
<span class="doccomment">/// Deallocates the buffer.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">dealloc</span>(<span class="self">self</span>) {
<span class="ident">drop</span>(<span class="ident">Vec::from_raw_parts</span>(<span class="self">self</span>.<span class="ident">ptr</span>, <span class="number">0</span>, <span class="self">self</span>.<span class="ident">cap</span>));
}
<span class="doccomment">/// Returns a pointer to the task at the specified `index`.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">at</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">index</span>: <span class="ident">isize</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">T</span> {
<span class="comment">// `self.cap` is always a power of two.</span>
<span class="self">self</span>.<span class="ident">ptr</span>.<span class="ident">offset</span>(<span class="ident">index</span> <span class="op">&</span> (<span class="self">self</span>.<span class="ident">cap</span> <span class="op">-</span> <span class="number">1</span>) <span class="kw">as</span> <span class="ident">isize</span>)
}
<span class="doccomment">/// Writes `task` into the specified `index`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This method might be concurrently called with another `read` at the same index, which is</span>
<span class="doccomment">/// technically speaking a data race and therefore UB. We should use an atomic store here, but</span>
<span class="doccomment">/// that would be more expensive and difficult to implement generically for all types `T`.</span>
<span class="doccomment">/// Hence, as a hack, we use a volatile write instead.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">write</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">index</span>: <span class="ident">isize</span>, <span class="ident">task</span>: <span class="ident">T</span>) {
<span class="ident">ptr::write_volatile</span>(<span class="self">self</span>.<span class="ident">at</span>(<span class="ident">index</span>), <span class="ident">task</span>)
}
<span class="doccomment">/// Reads a task from the specified `index`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This method might be concurrently called with another `write` at the same index, which is</span>
<span class="doccomment">/// technically speaking a data race and therefore UB. We should use an atomic load here, but</span>
<span class="doccomment">/// that would be more expensive and difficult to implement generically for all types `T`.</span>
<span class="doccomment">/// Hence, as a hack, we use a volatile write instead.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">read</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">index</span>: <span class="ident">isize</span>) <span class="op">-</span><span class="op">></span> <span class="ident">T</span> {
<span class="ident">ptr::read_volatile</span>(<span class="self">self</span>.<span class="ident">at</span>(<span class="ident">index</span>))
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Clone</span> <span class="kw">for</span> <span class="ident">Buffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">clone</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Buffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">Buffer</span> {
<span class="ident">ptr</span>: <span class="self">self</span>.<span class="ident">ptr</span>,
<span class="ident">cap</span>: <span class="self">self</span>.<span class="ident">cap</span>,
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Copy</span> <span class="kw">for</span> <span class="ident">Buffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="doccomment">/// Internal queue data shared between the worker and stealers.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The implementation is based on the following work:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// 1. [Chase and Lev. Dynamic circular work-stealing deque. SPAA 2005.][chase-lev]</span>
<span class="doccomment">/// 2. [Le, Pop, Cohen, and Nardelli. Correct and efficient work-stealing for weak memory models.</span>
<span class="doccomment">/// PPoPP 2013.][weak-mem]</span>
<span class="doccomment">/// 3. [Norris and Demsky. CDSchecker: checking concurrent data structures written with C/C++</span>
<span class="doccomment">/// atomics. OOPSLA 2013.][checker]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [chase-lev]: https://dl.acm.org/citation.cfm?id=1073974</span>
<span class="doccomment">/// [weak-mem]: https://dl.acm.org/citation.cfm?id=2442524</span>
<span class="doccomment">/// [checker]: https://dl.acm.org/citation.cfm?id=2509514</span>
<span class="kw">struct</span> <span class="ident">Inner</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// The front index.</span>
<span class="ident">front</span>: <span class="ident">AtomicIsize</span>,
<span class="doccomment">/// The back index.</span>
<span class="ident">back</span>: <span class="ident">AtomicIsize</span>,
<span class="doccomment">/// The underlying buffer.</span>
<span class="ident">buffer</span>: <span class="ident">CachePadded</span><span class="op"><</span><span class="ident">Atomic</span><span class="op"><</span><span class="ident">Buffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span><span class="op">></span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">Inner</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="comment">// Load the back index, front index, and buffer.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">buffer</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>, <span class="ident">epoch::unprotected</span>());
<span class="comment">// Go through the buffer from front to back and drop all tasks in the queue.</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">i</span> <span class="op">=</span> <span class="ident">f</span>;
<span class="kw">while</span> <span class="ident">i</span> <span class="op">!</span><span class="op">=</span> <span class="ident">b</span> {
<span class="ident">buffer</span>.<span class="ident">deref</span>().<span class="ident">at</span>(<span class="ident">i</span>).<span class="ident">drop_in_place</span>();
<span class="ident">i</span> <span class="op">=</span> <span class="ident">i</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>);
}
<span class="comment">// Free the memory allocated by the buffer.</span>
<span class="ident">buffer</span>.<span class="ident">into_owned</span>().<span class="ident">into_box</span>().<span class="ident">dealloc</span>();
}
}
}
<span class="doccomment">/// Worker queue flavor: FIFO or LIFO.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">enum</span> <span class="ident">Flavor</span> {
<span class="doccomment">/// The first-in first-out flavor.</span>
<span class="ident">Fifo</span>,
<span class="doccomment">/// The last-in first-out flavor.</span>
<span class="ident">Lifo</span>,
}
<span class="doccomment">/// A worker queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is a FIFO or LIFO queue that is owned by a single thread, but other threads may steal</span>
<span class="doccomment">/// tasks from it. Task schedulers typically create a single worker queue per thread.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A FIFO worker:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::{Steal, Worker};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_fifo();</span>
<span class="doccomment">/// let s = w.stealer();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// w.push(2);</span>
<span class="doccomment">/// w.push(3);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(s.steal(), Steal::Success(1));</span>
<span class="doccomment">/// assert_eq!(w.pop(), Some(2));</span>
<span class="doccomment">/// assert_eq!(w.pop(), Some(3));</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A LIFO worker:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::{Steal, Worker};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_lifo();</span>
<span class="doccomment">/// let s = w.stealer();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// w.push(2);</span>
<span class="doccomment">/// w.push(3);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(s.steal(), Steal::Success(1));</span>
<span class="doccomment">/// assert_eq!(w.pop(), Some(3));</span>
<span class="doccomment">/// assert_eq!(w.pop(), Some(2));</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// A reference to the inner representation of the queue.</span>
<span class="ident">inner</span>: <span class="ident">Arc</span><span class="op"><</span><span class="ident">CachePadded</span><span class="op"><</span><span class="ident">Inner</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span><span class="op">></span>,
<span class="doccomment">/// A copy of `inner.buffer` for quick access.</span>
<span class="ident">buffer</span>: <span class="ident">Cell</span><span class="op"><</span><span class="ident">Buffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span>,
<span class="doccomment">/// The flavor of the queue.</span>
<span class="ident">flavor</span>: <span class="ident">Flavor</span>,
<span class="doccomment">/// Indicates that the worker cannot be shared among threads.</span>
<span class="ident">_marker</span>: <span class="ident">PhantomData</span><span class="op"><</span><span class="kw-2">*</span><span class="kw-2">mut</span> ()<span class="op">></span>, <span class="comment">// !Send + !Sync</span>
}
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">Send</span> <span class="kw">for</span> <span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Creates a FIFO worker queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Tasks are pushed and popped from opposite ends.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::<i32>::new_fifo();</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new_fifo</span>() <span class="op">-</span><span class="op">></span> <span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="ident">Buffer::alloc</span>(<span class="ident">MIN_CAP</span>);
<span class="kw">let</span> <span class="ident">inner</span> <span class="op">=</span> <span class="ident">Arc::new</span>(<span class="ident">CachePadded::new</span>(<span class="ident">Inner</span> {
<span class="ident">front</span>: <span class="ident">AtomicIsize::new</span>(<span class="number">0</span>),
<span class="ident">back</span>: <span class="ident">AtomicIsize::new</span>(<span class="number">0</span>),
<span class="ident">buffer</span>: <span class="ident">CachePadded::new</span>(<span class="ident">Atomic::new</span>(<span class="ident">buffer</span>)),
}));
<span class="ident">Worker</span> {
<span class="ident">inner</span>,
<span class="ident">buffer</span>: <span class="ident">Cell::new</span>(<span class="ident">buffer</span>),
<span class="ident">flavor</span>: <span class="ident">Flavor::Fifo</span>,
<span class="ident">_marker</span>: <span class="ident">PhantomData</span>,
}
}
<span class="doccomment">/// Creates a LIFO worker queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Tasks are pushed and popped from the same end.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::<i32>::new_lifo();</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new_lifo</span>() <span class="op">-</span><span class="op">></span> <span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="ident">Buffer::alloc</span>(<span class="ident">MIN_CAP</span>);
<span class="kw">let</span> <span class="ident">inner</span> <span class="op">=</span> <span class="ident">Arc::new</span>(<span class="ident">CachePadded::new</span>(<span class="ident">Inner</span> {
<span class="ident">front</span>: <span class="ident">AtomicIsize::new</span>(<span class="number">0</span>),
<span class="ident">back</span>: <span class="ident">AtomicIsize::new</span>(<span class="number">0</span>),
<span class="ident">buffer</span>: <span class="ident">CachePadded::new</span>(<span class="ident">Atomic::new</span>(<span class="ident">buffer</span>)),
}));
<span class="ident">Worker</span> {
<span class="ident">inner</span>,
<span class="ident">buffer</span>: <span class="ident">Cell::new</span>(<span class="ident">buffer</span>),
<span class="ident">flavor</span>: <span class="ident">Flavor::Lifo</span>,
<span class="ident">_marker</span>: <span class="ident">PhantomData</span>,
}
}
<span class="doccomment">/// Creates a stealer for this queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The returned stealer can be shared among threads and cloned.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::<i32>::new_lifo();</span>
<span class="doccomment">/// let s = w.stealer();</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">stealer</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Stealer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">Stealer</span> {
<span class="ident">inner</span>: <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">clone</span>(),
<span class="ident">flavor</span>: <span class="self">self</span>.<span class="ident">flavor</span>,
}
}
<span class="doccomment">/// Resizes the internal buffer to the new capacity of `new_cap`.</span>
<span class="attribute">#[<span class="ident">cold</span>]</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">resize</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">new_cap</span>: <span class="ident">usize</span>) {
<span class="comment">// Load the back index, front index, and buffer.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">buffer</span>.<span class="ident">get</span>();
<span class="comment">// Allocate a new buffer and copy data from the old buffer to the new one.</span>
<span class="kw">let</span> <span class="ident">new</span> <span class="op">=</span> <span class="ident">Buffer::alloc</span>(<span class="ident">new_cap</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">i</span> <span class="op">=</span> <span class="ident">f</span>;
<span class="kw">while</span> <span class="ident">i</span> <span class="op">!</span><span class="op">=</span> <span class="ident">b</span> {
<span class="ident">ptr::copy_nonoverlapping</span>(<span class="ident">buffer</span>.<span class="ident">at</span>(<span class="ident">i</span>), <span class="ident">new</span>.<span class="ident">at</span>(<span class="ident">i</span>), <span class="number">1</span>);
<span class="ident">i</span> <span class="op">=</span> <span class="ident">i</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>);
}
<span class="kw">let</span> <span class="ident">guard</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">epoch::pin</span>();
<span class="comment">// Replace the old buffer with the new one.</span>
<span class="self">self</span>.<span class="ident">buffer</span>.<span class="ident">replace</span>(<span class="ident">new</span>);
<span class="kw">let</span> <span class="ident">old</span> <span class="op">=</span>
<span class="self">self</span>.<span class="ident">inner</span>
.<span class="ident">buffer</span>
.<span class="ident">swap</span>(<span class="ident">Owned::new</span>(<span class="ident">new</span>).<span class="ident">into_shared</span>(<span class="ident">guard</span>), <span class="ident">Ordering::Release</span>, <span class="ident">guard</span>);
<span class="comment">// Destroy the old buffer later.</span>
<span class="ident">guard</span>.<span class="ident">defer_unchecked</span>(<span class="kw">move</span> <span class="op">|</span><span class="op">|</span> <span class="ident">old</span>.<span class="ident">into_owned</span>().<span class="ident">into_box</span>().<span class="ident">dealloc</span>());
<span class="comment">// If the buffer is very large, then flush the thread-local garbage in order to deallocate</span>
<span class="comment">// it as soon as possible.</span>
<span class="kw">if</span> <span class="ident">mem::size_of</span>::<span class="op"><</span><span class="ident">T</span><span class="op">></span>() <span class="op">*</span> <span class="ident">new_cap</span> <span class="op">></span><span class="op">=</span> <span class="ident">FLUSH_THRESHOLD_BYTES</span> {
<span class="ident">guard</span>.<span class="ident">flush</span>();
}
}
<span class="doccomment">/// Reserves enough capacity so that `reserve_cap` tasks can be pushed without growing the</span>
<span class="doccomment">/// buffer.</span>
<span class="kw">fn</span> <span class="ident">reserve</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">reserve_cap</span>: <span class="ident">usize</span>) {
<span class="kw">if</span> <span class="ident">reserve_cap</span> <span class="op">></span> <span class="number">0</span> {
<span class="comment">// Compute the current length.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>) <span class="kw">as</span> <span class="ident">usize</span>;
<span class="comment">// The current capacity.</span>
<span class="kw">let</span> <span class="ident">cap</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">buffer</span>.<span class="ident">get</span>().<span class="ident">cap</span>;
<span class="comment">// Is there enough capacity to push `reserve_cap` tasks?</span>
<span class="kw">if</span> <span class="ident">cap</span> <span class="op">-</span> <span class="ident">len</span> <span class="op"><</span> <span class="ident">reserve_cap</span> {
<span class="comment">// Keep doubling the capacity as much as is needed.</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">new_cap</span> <span class="op">=</span> <span class="ident">cap</span> <span class="op">*</span> <span class="number">2</span>;
<span class="kw">while</span> <span class="ident">new_cap</span> <span class="op">-</span> <span class="ident">len</span> <span class="op"><</span> <span class="ident">reserve_cap</span> {
<span class="ident">new_cap</span> <span class="kw-2">*</span><span class="op">=</span> <span class="number">2</span>;
}
<span class="comment">// Resize the buffer.</span>
<span class="kw">unsafe</span> {
<span class="self">self</span>.<span class="ident">resize</span>(<span class="ident">new_cap</span>);
}
}
}
}
<span class="doccomment">/// Returns `true` if the queue is empty.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_lifo();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert!(w.is_empty());</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// assert!(!w.is_empty());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>) <span class="op"><</span><span class="op">=</span> <span class="number">0</span>
}
<span class="doccomment">/// Returns the number of tasks in the deque.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_lifo();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(w.len(), 0);</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// assert_eq!(w.len(), 1);</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// assert_eq!(w.len(), 2);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">len</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">usize</span> {
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>).<span class="ident">max</span>(<span class="number">0</span>) <span class="kw">as</span> <span class="ident">usize</span>
}
<span class="doccomment">/// Pushes a task into the queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_lifo();</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// w.push(2);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">push</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">task</span>: <span class="ident">T</span>) {
<span class="comment">// Load the back index, front index, and buffer.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">buffer</span>.<span class="ident">get</span>();
<span class="comment">// Calculate the length of the queue.</span>
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>);
<span class="comment">// Is the queue full?</span>
<span class="kw">if</span> <span class="ident">len</span> <span class="op">></span><span class="op">=</span> <span class="ident">buffer</span>.<span class="ident">cap</span> <span class="kw">as</span> <span class="ident">isize</span> {
<span class="comment">// Yes. Grow the underlying buffer.</span>
<span class="kw">unsafe</span> {
<span class="self">self</span>.<span class="ident">resize</span>(<span class="number">2</span> <span class="op">*</span> <span class="ident">buffer</span>.<span class="ident">cap</span>);
}
<span class="ident">buffer</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">buffer</span>.<span class="ident">get</span>();
}
<span class="comment">// Write `task` into the slot.</span>
<span class="kw">unsafe</span> {
<span class="ident">buffer</span>.<span class="ident">write</span>(<span class="ident">b</span>, <span class="ident">task</span>);
}
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::Release</span>);
<span class="comment">// Increment the back index.</span>
<span class="comment">//</span>
<span class="comment">// This ordering could be `Relaxed`, but then thread sanitizer would falsely report data</span>
<span class="comment">// races because it doesn't understand fences.</span>
<span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">store</span>(<span class="ident">b</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>), <span class="ident">Ordering::Release</span>);
}
<span class="doccomment">/// Pops a task from the queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_fifo();</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// w.push(2);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(w.pop(), Some(1));</span>
<span class="doccomment">/// assert_eq!(w.pop(), Some(2));</span>
<span class="doccomment">/// assert_eq!(w.pop(), None);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">pop</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="comment">// Load the back and front index.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="comment">// Calculate the length of the queue.</span>
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>);
<span class="comment">// Is the queue empty?</span>
<span class="kw">if</span> <span class="ident">len</span> <span class="op"><</span><span class="op">=</span> <span class="number">0</span> {
<span class="kw">return</span> <span class="prelude-val">None</span>;
}
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">flavor</span> {
<span class="comment">// Pop from the front of the queue.</span>
<span class="ident">Flavor::Fifo</span> <span class="op">=</span><span class="op">></span> {
<span class="comment">// Try incrementing the front index to pop the task.</span>
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">fetch_add</span>(<span class="number">1</span>, <span class="ident">Ordering::SeqCst</span>);
<span class="kw">let</span> <span class="ident">new_f</span> <span class="op">=</span> <span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>);
<span class="kw">if</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">new_f</span>) <span class="op"><</span> <span class="number">0</span> {
<span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">store</span>(<span class="ident">f</span>, <span class="ident">Ordering::Relaxed</span>);
<span class="kw">return</span> <span class="prelude-val">None</span>;
}
<span class="kw">unsafe</span> {
<span class="comment">// Read the popped task.</span>
<span class="kw">let</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">buffer</span>.<span class="ident">get</span>();
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">buffer</span>.<span class="ident">read</span>(<span class="ident">f</span>);
<span class="comment">// Shrink the buffer if `len - 1` is less than one fourth of the capacity.</span>
<span class="kw">if</span> <span class="ident">buffer</span>.<span class="ident">cap</span> <span class="op">></span> <span class="ident">MIN_CAP</span> <span class="op">&&</span> <span class="ident">len</span> <span class="op"><</span><span class="op">=</span> <span class="ident">buffer</span>.<span class="ident">cap</span> <span class="kw">as</span> <span class="ident">isize</span> <span class="op">/</span> <span class="number">4</span> {
<span class="self">self</span>.<span class="ident">resize</span>(<span class="ident">buffer</span>.<span class="ident">cap</span> <span class="op">/</span> <span class="number">2</span>);
}
<span class="prelude-val">Some</span>(<span class="ident">task</span>)
}
}
<span class="comment">// Pop from the back of the queue.</span>
<span class="ident">Flavor::Lifo</span> <span class="op">=</span><span class="op">></span> {
<span class="comment">// Decrement the back index.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="number">1</span>);
<span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">store</span>(<span class="ident">b</span>, <span class="ident">Ordering::Relaxed</span>);
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="comment">// Load the front index.</span>
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="comment">// Compute the length after the back index was decremented.</span>
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>);
<span class="kw">if</span> <span class="ident">len</span> <span class="op"><</span> <span class="number">0</span> {
<span class="comment">// The queue is empty. Restore the back index to the original task.</span>
<span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">store</span>(<span class="ident">b</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>), <span class="ident">Ordering::Relaxed</span>);
<span class="prelude-val">None</span>
} <span class="kw">else</span> {
<span class="comment">// Read the task to be popped.</span>
<span class="kw">let</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">buffer</span>.<span class="ident">get</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">task</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="prelude-val">Some</span>(<span class="ident">buffer</span>.<span class="ident">read</span>(<span class="ident">b</span>)) };
<span class="comment">// Are we popping the last task from the queue?</span>
<span class="kw">if</span> <span class="ident">len</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="comment">// Try incrementing the front index.</span>
<span class="kw">if</span> <span class="self">self</span>
.<span class="ident">inner</span>
.<span class="ident">front</span>
.<span class="ident">compare_exchange</span>(
<span class="ident">f</span>,
<span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>),
<span class="ident">Ordering::SeqCst</span>,
<span class="ident">Ordering::Relaxed</span>,
)
.<span class="ident">is_err</span>()
{
<span class="comment">// Failed. We didn't pop anything.</span>
<span class="ident">mem::forget</span>(<span class="ident">task</span>.<span class="ident">take</span>());
}
<span class="comment">// Restore the back index to the original task.</span>
<span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">store</span>(<span class="ident">b</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>), <span class="ident">Ordering::Relaxed</span>);
} <span class="kw">else</span> {
<span class="comment">// Shrink the buffer if `len` is less than one fourth of the capacity.</span>
<span class="kw">if</span> <span class="ident">buffer</span>.<span class="ident">cap</span> <span class="op">></span> <span class="ident">MIN_CAP</span> <span class="op">&&</span> <span class="ident">len</span> <span class="op"><</span> <span class="ident">buffer</span>.<span class="ident">cap</span> <span class="kw">as</span> <span class="ident">isize</span> <span class="op">/</span> <span class="number">4</span> {
<span class="kw">unsafe</span> {
<span class="self">self</span>.<span class="ident">resize</span>(<span class="ident">buffer</span>.<span class="ident">cap</span> <span class="op">/</span> <span class="number">2</span>);
}
}
}
<span class="ident">task</span>
}
}
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">fmt::Debug</span> <span class="kw">for</span> <span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt::Formatter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt::Result</span> {
<span class="ident">f</span>.<span class="ident">pad</span>(<span class="string">"Worker { .. }"</span>)
}
}
<span class="doccomment">/// A stealer handle of a worker queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Stealers can be shared among threads.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Task schedulers typically have a single worker queue per worker thread.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::{Steal, Worker};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_lifo();</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// w.push(2);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let s = w.stealer();</span>
<span class="doccomment">/// assert_eq!(s.steal(), Steal::Success(1));</span>
<span class="doccomment">/// assert_eq!(s.steal(), Steal::Success(2));</span>
<span class="doccomment">/// assert_eq!(s.steal(), Steal::Empty);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Stealer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// A reference to the inner representation of the queue.</span>
<span class="ident">inner</span>: <span class="ident">Arc</span><span class="op"><</span><span class="ident">CachePadded</span><span class="op"><</span><span class="ident">Inner</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span><span class="op">></span>,
<span class="doccomment">/// The flavor of the queue.</span>
<span class="ident">flavor</span>: <span class="ident">Flavor</span>,
}
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">Send</span> <span class="kw">for</span> <span class="ident">Stealer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">Sync</span> <span class="kw">for</span> <span class="ident">Stealer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Stealer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Returns `true` if the queue is empty.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_lifo();</span>
<span class="doccomment">/// let s = w.stealer();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert!(s.is_empty());</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// assert!(!s.is_empty());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>) <span class="op"><</span><span class="op">=</span> <span class="number">0</span>
}
<span class="doccomment">/// Returns the number of tasks in the deque.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_lifo();</span>
<span class="doccomment">/// let s = w.stealer();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(s.len(), 0);</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// assert_eq!(s.len(), 1);</span>
<span class="doccomment">/// w.push(2);</span>
<span class="doccomment">/// assert_eq!(s.len(), 2);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">len</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">usize</span> {
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>).<span class="ident">max</span>(<span class="number">0</span>) <span class="kw">as</span> <span class="ident">usize</span>
}
<span class="doccomment">/// Steals a task from the queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::{Steal, Worker};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_lifo();</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// w.push(2);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let s = w.stealer();</span>
<span class="doccomment">/// assert_eq!(s.steal(), Steal::Success(1));</span>
<span class="doccomment">/// assert_eq!(s.steal(), Steal::Success(2));</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">steal</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="comment">// Load the front index.</span>
<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// A SeqCst fence is needed here.</span>
<span class="comment">//</span>
<span class="comment">// If the current thread is already pinned (reentrantly), we must manually issue the</span>
<span class="comment">// fence. Otherwise, the following pinning will issue the fence anyway, so we don't</span>
<span class="comment">// have to.</span>
<span class="kw">if</span> <span class="ident">epoch::is_pinned</span>() {
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
}
<span class="kw">let</span> <span class="ident">guard</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">epoch::pin</span>();
<span class="comment">// Load the back index.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// Is the queue empty?</span>
<span class="kw">if</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>) <span class="op"><</span><span class="op">=</span> <span class="number">0</span> {
<span class="kw">return</span> <span class="ident">Steal::Empty</span>;
}
<span class="comment">// Load the buffer and read the task at the front.</span>
<span class="kw">let</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buffer</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>, <span class="ident">guard</span>);
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">buffer</span>.<span class="ident">deref</span>().<span class="ident">read</span>(<span class="ident">f</span>) };
<span class="comment">// Try incrementing the front index to steal the task.</span>
<span class="comment">// If the buffer has been swapped or the increment fails, we retry.</span>
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buffer</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>, <span class="ident">guard</span>) <span class="op">!</span><span class="op">=</span> <span class="ident">buffer</span>
<span class="op">|</span><span class="op">|</span> <span class="self">self</span>
.<span class="ident">inner</span>
.<span class="ident">front</span>
.<span class="ident">compare_exchange</span>(<span class="ident">f</span>, <span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>), <span class="ident">Ordering::SeqCst</span>, <span class="ident">Ordering::Relaxed</span>)
.<span class="ident">is_err</span>()
{
<span class="comment">// We didn't steal this task, forget it.</span>
<span class="ident">mem::forget</span>(<span class="ident">task</span>);
<span class="kw">return</span> <span class="ident">Steal::Retry</span>;
}
<span class="comment">// Return the stolen task.</span>
<span class="ident">Steal::Success</span>(<span class="ident">task</span>)
}
<span class="doccomment">/// Steals a batch of tasks and pushes them into another worker.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// How many tasks exactly will be stolen is not specified. That said, this method will try to</span>
<span class="doccomment">/// steal around half of the tasks in the queue, but also not more than some constant limit.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Worker;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w1 = Worker::new_fifo();</span>
<span class="doccomment">/// w1.push(1);</span>
<span class="doccomment">/// w1.push(2);</span>
<span class="doccomment">/// w1.push(3);</span>
<span class="doccomment">/// w1.push(4);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let s = w1.stealer();</span>
<span class="doccomment">/// let w2 = Worker::new_fifo();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let _ = s.steal_batch(&w2);</span>
<span class="doccomment">/// assert_eq!(w2.pop(), Some(1));</span>
<span class="doccomment">/// assert_eq!(w2.pop(), Some(2));</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">steal_batch</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">dest</span>: <span class="kw-2">&</span><span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span>()<span class="op">></span> {
<span class="kw">if</span> <span class="ident">Arc::ptr_eq</span>(<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">inner</span>, <span class="kw-2">&</span><span class="ident">dest</span>.<span class="ident">inner</span>) {
<span class="kw">if</span> <span class="ident">dest</span>.<span class="ident">is_empty</span>() {
<span class="kw">return</span> <span class="ident">Steal::Empty</span>;
} <span class="kw">else</span> {
<span class="kw">return</span> <span class="ident">Steal::Success</span>(());
}
}
<span class="comment">// Load the front index.</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// A SeqCst fence is needed here.</span>
<span class="comment">//</span>
<span class="comment">// If the current thread is already pinned (reentrantly), we must manually issue the</span>
<span class="comment">// fence. Otherwise, the following pinning will issue the fence anyway, so we don't</span>
<span class="comment">// have to.</span>
<span class="kw">if</span> <span class="ident">epoch::is_pinned</span>() {
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
}
<span class="kw">let</span> <span class="ident">guard</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">epoch::pin</span>();
<span class="comment">// Load the back index.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// Is the queue empty?</span>
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>);
<span class="kw">if</span> <span class="ident">len</span> <span class="op"><</span><span class="op">=</span> <span class="number">0</span> {
<span class="kw">return</span> <span class="ident">Steal::Empty</span>;
}
<span class="comment">// Reserve capacity for the stolen batch.</span>
<span class="kw">let</span> <span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">cmp::min</span>((<span class="ident">len</span> <span class="kw">as</span> <span class="ident">usize</span> <span class="op">+</span> <span class="number">1</span>) <span class="op">/</span> <span class="number">2</span>, <span class="ident">MAX_BATCH</span>);
<span class="ident">dest</span>.<span class="ident">reserve</span>(<span class="ident">batch_size</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">batch_size</span> <span class="kw">as</span> <span class="ident">isize</span>;
<span class="comment">// Get the destination buffer and back index.</span>
<span class="kw">let</span> <span class="ident">dest_buffer</span> <span class="op">=</span> <span class="ident">dest</span>.<span class="ident">buffer</span>.<span class="ident">get</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">dest_b</span> <span class="op">=</span> <span class="ident">dest</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="comment">// Load the buffer.</span>
<span class="kw">let</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buffer</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>, <span class="ident">guard</span>);
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">flavor</span> {
<span class="comment">// Steal a batch of tasks from the front at once.</span>
<span class="ident">Flavor::Fifo</span> <span class="op">=</span><span class="op">></span> {
<span class="comment">// Copy the batch from the source to the destination buffer.</span>
<span class="kw">match</span> <span class="ident">dest</span>.<span class="ident">flavor</span> {
<span class="ident">Flavor::Fifo</span> <span class="op">=</span><span class="op">></span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> {
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">buffer</span>.<span class="ident">deref</span>().<span class="ident">read</span>(<span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="ident">i</span>));
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">i</span>), <span class="ident">task</span>);
}
}
}
<span class="ident">Flavor::Lifo</span> <span class="op">=</span><span class="op">></span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> {
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">buffer</span>.<span class="ident">deref</span>().<span class="ident">read</span>(<span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="ident">i</span>));
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">batch_size</span> <span class="op">-</span> <span class="number">1</span> <span class="op">-</span> <span class="ident">i</span>), <span class="ident">task</span>);
}
}
}
}
<span class="comment">// Try incrementing the front index to steal the batch.</span>
<span class="comment">// If the buffer has been swapped or the increment fails, we retry.</span>
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buffer</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>, <span class="ident">guard</span>) <span class="op">!</span><span class="op">=</span> <span class="ident">buffer</span>
<span class="op">|</span><span class="op">|</span> <span class="self">self</span>
.<span class="ident">inner</span>
.<span class="ident">front</span>
.<span class="ident">compare_exchange</span>(
<span class="ident">f</span>,
<span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="ident">batch_size</span>),
<span class="ident">Ordering::SeqCst</span>,
<span class="ident">Ordering::Relaxed</span>,
)
.<span class="ident">is_err</span>()
{
<span class="kw">return</span> <span class="ident">Steal::Retry</span>;
}
<span class="ident">dest_b</span> <span class="op">=</span> <span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">batch_size</span>);
}
<span class="comment">// Steal a batch of tasks from the front one by one.</span>
<span class="ident">Flavor::Lifo</span> <span class="op">=</span><span class="op">></span> {
<span class="comment">// This loop may modify the batch_size, which triggers a clippy lint warning.</span>
<span class="comment">// Use a new variable to avoid the warning, and to make it clear we aren't</span>
<span class="comment">// modifying the loop exit condition during iteration.</span>
<span class="kw">let</span> <span class="ident">original_batch_size</span> <span class="op">=</span> <span class="ident">batch_size</span>;
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">original_batch_size</span> {
<span class="comment">// If this is not the first steal, check whether the queue is empty.</span>
<span class="kw">if</span> <span class="ident">i</span> <span class="op">></span> <span class="number">0</span> {
<span class="comment">// We've already got the current front index. Now execute the fence to</span>
<span class="comment">// synchronize with other threads.</span>
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="comment">// Load the back index.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// Is the queue empty?</span>
<span class="kw">if</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>) <span class="op"><</span><span class="op">=</span> <span class="number">0</span> {
<span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">i</span>;
<span class="kw">break</span>;
}
}
<span class="comment">// Read the task at the front.</span>
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">buffer</span>.<span class="ident">deref</span>().<span class="ident">read</span>(<span class="ident">f</span>) };
<span class="comment">// Try incrementing the front index to steal the task.</span>
<span class="comment">// If the buffer has been swapped or the increment fails, we retry.</span>
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buffer</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>, <span class="ident">guard</span>) <span class="op">!</span><span class="op">=</span> <span class="ident">buffer</span>
<span class="op">|</span><span class="op">|</span> <span class="self">self</span>
.<span class="ident">inner</span>
.<span class="ident">front</span>
.<span class="ident">compare_exchange</span>(
<span class="ident">f</span>,
<span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>),
<span class="ident">Ordering::SeqCst</span>,
<span class="ident">Ordering::Relaxed</span>,
)
.<span class="ident">is_err</span>()
{
<span class="comment">// We didn't steal this task, forget it and break from the loop.</span>
<span class="ident">mem::forget</span>(<span class="ident">task</span>);
<span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">i</span>;
<span class="kw">break</span>;
}
<span class="comment">// Write the stolen task into the destination buffer.</span>
<span class="kw">unsafe</span> {
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>, <span class="ident">task</span>);
}
<span class="comment">// Move the source front index and the destination back index one step forward.</span>
<span class="ident">f</span> <span class="op">=</span> <span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>);
<span class="ident">dest_b</span> <span class="op">=</span> <span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>);
}
<span class="comment">// If we didn't steal anything, the operation needs to be retried.</span>
<span class="kw">if</span> <span class="ident">batch_size</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="kw">return</span> <span class="ident">Steal::Retry</span>;
}
<span class="comment">// If stealing into a FIFO queue, stolen tasks need to be reversed.</span>
<span class="kw">if</span> <span class="ident">dest</span>.<span class="ident">flavor</span> <span class="op">=</span><span class="op">=</span> <span class="ident">Flavor::Fifo</span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> <span class="op">/</span> <span class="number">2</span> {
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">i1</span> <span class="op">=</span> <span class="ident">dest_b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">batch_size</span> <span class="op">-</span> <span class="ident">i</span>);
<span class="kw">let</span> <span class="ident">i2</span> <span class="op">=</span> <span class="ident">dest_b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>);
<span class="kw">let</span> <span class="ident">t1</span> <span class="op">=</span> <span class="ident">dest_buffer</span>.<span class="ident">read</span>(<span class="ident">i1</span>);
<span class="kw">let</span> <span class="ident">t2</span> <span class="op">=</span> <span class="ident">dest_buffer</span>.<span class="ident">read</span>(<span class="ident">i2</span>);
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">i1</span>, <span class="ident">t2</span>);
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">i2</span>, <span class="ident">t1</span>);
}
}
}
}
}
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::Release</span>);
<span class="comment">// Update the back index in the destination queue.</span>
<span class="comment">//</span>
<span class="comment">// This ordering could be `Relaxed`, but then thread sanitizer would falsely report data</span>
<span class="comment">// races because it doesn't understand fences.</span>
<span class="ident">dest</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">store</span>(<span class="ident">dest_b</span>, <span class="ident">Ordering::Release</span>);
<span class="comment">// Return with success.</span>
<span class="ident">Steal::Success</span>(())
}
<span class="doccomment">/// Steals a batch of tasks, pushes them into another worker, and pops a task from that worker.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// How many tasks exactly will be stolen is not specified. That said, this method will try to</span>
<span class="doccomment">/// steal around half of the tasks in the queue, but also not more than some constant limit.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::{Steal, Worker};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w1 = Worker::new_fifo();</span>
<span class="doccomment">/// w1.push(1);</span>
<span class="doccomment">/// w1.push(2);</span>
<span class="doccomment">/// w1.push(3);</span>
<span class="doccomment">/// w1.push(4);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let s = w1.stealer();</span>
<span class="doccomment">/// let w2 = Worker::new_fifo();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(s.steal_batch_and_pop(&w2), Steal::Success(1));</span>
<span class="doccomment">/// assert_eq!(w2.pop(), Some(2));</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">steal_batch_and_pop</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">dest</span>: <span class="kw-2">&</span><span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">if</span> <span class="ident">Arc::ptr_eq</span>(<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">inner</span>, <span class="kw-2">&</span><span class="ident">dest</span>.<span class="ident">inner</span>) {
<span class="kw">match</span> <span class="ident">dest</span>.<span class="ident">pop</span>() {
<span class="prelude-val">None</span> <span class="op">=</span><span class="op">></span> <span class="kw">return</span> <span class="ident">Steal::Empty</span>,
<span class="prelude-val">Some</span>(<span class="ident">task</span>) <span class="op">=</span><span class="op">></span> <span class="kw">return</span> <span class="ident">Steal::Success</span>(<span class="ident">task</span>),
}
}
<span class="comment">// Load the front index.</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">f</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">front</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// A SeqCst fence is needed here.</span>
<span class="comment">//</span>
<span class="comment">// If the current thread is already pinned (reentrantly), we must manually issue the</span>
<span class="comment">// fence. Otherwise, the following pinning will issue the fence anyway, so we don't</span>
<span class="comment">// have to.</span>
<span class="kw">if</span> <span class="ident">epoch::is_pinned</span>() {
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
}
<span class="kw">let</span> <span class="ident">guard</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">epoch::pin</span>();
<span class="comment">// Load the back index.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// Is the queue empty?</span>
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>);
<span class="kw">if</span> <span class="ident">len</span> <span class="op"><</span><span class="op">=</span> <span class="number">0</span> {
<span class="kw">return</span> <span class="ident">Steal::Empty</span>;
}
<span class="comment">// Reserve capacity for the stolen batch.</span>
<span class="kw">let</span> <span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">cmp::min</span>((<span class="ident">len</span> <span class="kw">as</span> <span class="ident">usize</span> <span class="op">-</span> <span class="number">1</span>) <span class="op">/</span> <span class="number">2</span>, <span class="ident">MAX_BATCH</span> <span class="op">-</span> <span class="number">1</span>);
<span class="ident">dest</span>.<span class="ident">reserve</span>(<span class="ident">batch_size</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">batch_size</span> <span class="kw">as</span> <span class="ident">isize</span>;
<span class="comment">// Get the destination buffer and back index.</span>
<span class="kw">let</span> <span class="ident">dest_buffer</span> <span class="op">=</span> <span class="ident">dest</span>.<span class="ident">buffer</span>.<span class="ident">get</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">dest_b</span> <span class="op">=</span> <span class="ident">dest</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="comment">// Load the buffer</span>
<span class="kw">let</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buffer</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>, <span class="ident">guard</span>);
<span class="comment">// Read the task at the front.</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">task</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">buffer</span>.<span class="ident">deref</span>().<span class="ident">read</span>(<span class="ident">f</span>) };
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">flavor</span> {
<span class="comment">// Steal a batch of tasks from the front at once.</span>
<span class="ident">Flavor::Fifo</span> <span class="op">=</span><span class="op">></span> {
<span class="comment">// Copy the batch from the source to the destination buffer.</span>
<span class="kw">match</span> <span class="ident">dest</span>.<span class="ident">flavor</span> {
<span class="ident">Flavor::Fifo</span> <span class="op">=</span><span class="op">></span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> {
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">buffer</span>.<span class="ident">deref</span>().<span class="ident">read</span>(<span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>));
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">i</span>), <span class="ident">task</span>);
}
}
}
<span class="ident">Flavor::Lifo</span> <span class="op">=</span><span class="op">></span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> {
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">buffer</span>.<span class="ident">deref</span>().<span class="ident">read</span>(<span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>));
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">batch_size</span> <span class="op">-</span> <span class="number">1</span> <span class="op">-</span> <span class="ident">i</span>), <span class="ident">task</span>);
}
}
}
}
<span class="comment">// Try incrementing the front index to steal the task.</span>
<span class="comment">// If the buffer has been swapped or the increment fails, we retry.</span>
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buffer</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>, <span class="ident">guard</span>) <span class="op">!</span><span class="op">=</span> <span class="ident">buffer</span>
<span class="op">|</span><span class="op">|</span> <span class="self">self</span>
.<span class="ident">inner</span>
.<span class="ident">front</span>
.<span class="ident">compare_exchange</span>(
<span class="ident">f</span>,
<span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="ident">batch_size</span> <span class="op">+</span> <span class="number">1</span>),
<span class="ident">Ordering::SeqCst</span>,
<span class="ident">Ordering::Relaxed</span>,
)
.<span class="ident">is_err</span>()
{
<span class="comment">// We didn't steal this task, forget it.</span>
<span class="ident">mem::forget</span>(<span class="ident">task</span>);
<span class="kw">return</span> <span class="ident">Steal::Retry</span>;
}
<span class="ident">dest_b</span> <span class="op">=</span> <span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">batch_size</span>);
}
<span class="comment">// Steal a batch of tasks from the front one by one.</span>
<span class="ident">Flavor::Lifo</span> <span class="op">=</span><span class="op">></span> {
<span class="comment">// Try incrementing the front index to steal the task.</span>
<span class="kw">if</span> <span class="self">self</span>
.<span class="ident">inner</span>
.<span class="ident">front</span>
.<span class="ident">compare_exchange</span>(<span class="ident">f</span>, <span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>), <span class="ident">Ordering::SeqCst</span>, <span class="ident">Ordering::Relaxed</span>)
.<span class="ident">is_err</span>()
{
<span class="comment">// We didn't steal this task, forget it.</span>
<span class="ident">mem::forget</span>(<span class="ident">task</span>);
<span class="kw">return</span> <span class="ident">Steal::Retry</span>;
}
<span class="comment">// Move the front index one step forward.</span>
<span class="ident">f</span> <span class="op">=</span> <span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>);
<span class="comment">// Repeat the same procedure for the batch steals.</span>
<span class="comment">//</span>
<span class="comment">// This loop may modify the batch_size, which triggers a clippy lint warning.</span>
<span class="comment">// Use a new variable to avoid the warning, and to make it clear we aren't</span>
<span class="comment">// modifying the loop exit condition during iteration.</span>
<span class="kw">let</span> <span class="ident">original_batch_size</span> <span class="op">=</span> <span class="ident">batch_size</span>;
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">original_batch_size</span> {
<span class="comment">// We've already got the current front index. Now execute the fence to</span>
<span class="comment">// synchronize with other threads.</span>
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="comment">// Load the back index.</span>
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// Is the queue empty?</span>
<span class="kw">if</span> <span class="ident">b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">f</span>) <span class="op"><</span><span class="op">=</span> <span class="number">0</span> {
<span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">i</span>;
<span class="kw">break</span>;
}
<span class="comment">// Read the task at the front.</span>
<span class="kw">let</span> <span class="ident">tmp</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">buffer</span>.<span class="ident">deref</span>().<span class="ident">read</span>(<span class="ident">f</span>) };
<span class="comment">// Try incrementing the front index to steal the task.</span>
<span class="comment">// If the buffer has been swapped or the increment fails, we retry.</span>
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buffer</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>, <span class="ident">guard</span>) <span class="op">!</span><span class="op">=</span> <span class="ident">buffer</span>
<span class="op">|</span><span class="op">|</span> <span class="self">self</span>
.<span class="ident">inner</span>
.<span class="ident">front</span>
.<span class="ident">compare_exchange</span>(
<span class="ident">f</span>,
<span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>),
<span class="ident">Ordering::SeqCst</span>,
<span class="ident">Ordering::Relaxed</span>,
)
.<span class="ident">is_err</span>()
{
<span class="comment">// We didn't steal this task, forget it and break from the loop.</span>
<span class="ident">mem::forget</span>(<span class="ident">tmp</span>);
<span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">i</span>;
<span class="kw">break</span>;
}
<span class="comment">// Write the previously stolen task into the destination buffer.</span>
<span class="kw">unsafe</span> {
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>, <span class="ident">mem::replace</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">task</span>, <span class="ident">tmp</span>));
}
<span class="comment">// Move the source front index and the destination back index one step forward.</span>
<span class="ident">f</span> <span class="op">=</span> <span class="ident">f</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>);
<span class="ident">dest_b</span> <span class="op">=</span> <span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>);
}
<span class="comment">// If stealing into a FIFO queue, stolen tasks need to be reversed.</span>
<span class="kw">if</span> <span class="ident">dest</span>.<span class="ident">flavor</span> <span class="op">=</span><span class="op">=</span> <span class="ident">Flavor::Fifo</span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> <span class="op">/</span> <span class="number">2</span> {
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">i1</span> <span class="op">=</span> <span class="ident">dest_b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">batch_size</span> <span class="op">-</span> <span class="ident">i</span>);
<span class="kw">let</span> <span class="ident">i2</span> <span class="op">=</span> <span class="ident">dest_b</span>.<span class="ident">wrapping_sub</span>(<span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>);
<span class="kw">let</span> <span class="ident">t1</span> <span class="op">=</span> <span class="ident">dest_buffer</span>.<span class="ident">read</span>(<span class="ident">i1</span>);
<span class="kw">let</span> <span class="ident">t2</span> <span class="op">=</span> <span class="ident">dest_buffer</span>.<span class="ident">read</span>(<span class="ident">i2</span>);
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">i1</span>, <span class="ident">t2</span>);
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">i2</span>, <span class="ident">t1</span>);
}
}
}
}
}
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::Release</span>);
<span class="comment">// Update the back index in the destination queue.</span>
<span class="comment">//</span>
<span class="comment">// This ordering could be `Relaxed`, but then thread sanitizer would falsely report data</span>
<span class="comment">// races because it doesn't understand fences.</span>
<span class="ident">dest</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">store</span>(<span class="ident">dest_b</span>, <span class="ident">Ordering::Release</span>);
<span class="comment">// Return with success.</span>
<span class="ident">Steal::Success</span>(<span class="ident">task</span>)
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Clone</span> <span class="kw">for</span> <span class="ident">Stealer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">clone</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Stealer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">Stealer</span> {
<span class="ident">inner</span>: <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">clone</span>(),
<span class="ident">flavor</span>: <span class="self">self</span>.<span class="ident">flavor</span>,
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">fmt::Debug</span> <span class="kw">for</span> <span class="ident">Stealer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt::Formatter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt::Result</span> {
<span class="ident">f</span>.<span class="ident">pad</span>(<span class="string">"Stealer { .. }"</span>)
}
}
<span class="comment">// Bits indicating the state of a slot:</span>
<span class="comment">// * If a task has been written into the slot, `WRITE` is set.</span>
<span class="comment">// * If a task has been read from the slot, `READ` is set.</span>
<span class="comment">// * If the block is being destroyed, `DESTROY` is set.</span>
<span class="kw">const</span> <span class="ident">WRITE</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">1</span>;
<span class="kw">const</span> <span class="ident">READ</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">2</span>;
<span class="kw">const</span> <span class="ident">DESTROY</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">4</span>;
<span class="comment">// Each block covers one "lap" of indices.</span>
<span class="kw">const</span> <span class="ident">LAP</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">64</span>;
<span class="comment">// The maximum number of values a block can hold.</span>
<span class="kw">const</span> <span class="ident">BLOCK_CAP</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="ident">LAP</span> <span class="op">-</span> <span class="number">1</span>;
<span class="comment">// How many lower bits are reserved for metadata.</span>
<span class="kw">const</span> <span class="ident">SHIFT</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">1</span>;
<span class="comment">// Indicates that the block is not the last one.</span>
<span class="kw">const</span> <span class="ident">HAS_NEXT</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">1</span>;
<span class="doccomment">/// A slot in a block.</span>
<span class="kw">struct</span> <span class="ident">Slot</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// The task.</span>
<span class="ident">task</span>: <span class="ident">UnsafeCell</span><span class="op"><</span><span class="ident">MaybeUninit</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span>,
<span class="doccomment">/// The state of the slot.</span>
<span class="ident">state</span>: <span class="ident">AtomicUsize</span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Slot</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Waits until a task is written into the slot.</span>
<span class="kw">fn</span> <span class="ident">wait_write</span>(<span class="kw-2">&</span><span class="self">self</span>) {
<span class="kw">let</span> <span class="ident">backoff</span> <span class="op">=</span> <span class="ident">Backoff::new</span>();
<span class="kw">while</span> <span class="self">self</span>.<span class="ident">state</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>) <span class="op">&</span> <span class="ident">WRITE</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="ident">backoff</span>.<span class="ident">snooze</span>();
}
}
}
<span class="doccomment">/// A block in a linked list.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Each block in the list can hold up to `BLOCK_CAP` values.</span>
<span class="kw">struct</span> <span class="ident">Block</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// The next block in the linked list.</span>
<span class="ident">next</span>: <span class="ident">AtomicPtr</span><span class="op"><</span><span class="ident">Block</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span>,
<span class="doccomment">/// Slots for values.</span>
<span class="ident">slots</span>: [<span class="ident">Slot</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>; <span class="ident">BLOCK_CAP</span>],
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Block</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Creates an empty block that starts at `start_index`.</span>
<span class="kw">fn</span> <span class="ident">new</span>() <span class="op">-</span><span class="op">></span> <span class="ident">Block</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="comment">// SAFETY: This is safe because:</span>
<span class="comment">// [1] `Block::next` (AtomicPtr) may be safely zero initialized.</span>
<span class="comment">// [2] `Block::slots` (Array) may be safely zero initialized because of [3, 4].</span>
<span class="comment">// [3] `Slot::task` (UnsafeCell) may be safely zero initialized because it</span>
<span class="comment">// holds a MaybeUninit.</span>
<span class="comment">// [4] `Slot::state` (AtomicUsize) may be safely zero initialized.</span>
<span class="kw">unsafe</span> { <span class="ident">MaybeUninit::zeroed</span>().<span class="ident">assume_init</span>() }
}
<span class="doccomment">/// Waits until the next pointer is set.</span>
<span class="kw">fn</span> <span class="ident">wait_next</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">Block</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">backoff</span> <span class="op">=</span> <span class="ident">Backoff::new</span>();
<span class="kw">loop</span> {
<span class="kw">let</span> <span class="ident">next</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">next</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="kw">if</span> <span class="op">!</span><span class="ident">next</span>.<span class="ident">is_null</span>() {
<span class="kw">return</span> <span class="ident">next</span>;
}
<span class="ident">backoff</span>.<span class="ident">snooze</span>();
}
}
<span class="doccomment">/// Sets the `DESTROY` bit in slots starting from `start` and destroys the block.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">destroy</span>(<span class="ident">this</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">Block</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>, <span class="ident">count</span>: <span class="ident">usize</span>) {
<span class="comment">// It is not necessary to set the `DESTROY` bit in the last slot because that slot has</span>
<span class="comment">// begun destruction of the block.</span>
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> (<span class="number">0</span>..<span class="ident">count</span>).<span class="ident">rev</span>() {
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">this</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>);
<span class="comment">// Mark the `DESTROY` bit if a thread is still using the slot.</span>
<span class="kw">if</span> <span class="ident">slot</span>.<span class="ident">state</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>) <span class="op">&</span> <span class="ident">READ</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span>
<span class="op">&&</span> <span class="ident">slot</span>.<span class="ident">state</span>.<span class="ident">fetch_or</span>(<span class="ident">DESTROY</span>, <span class="ident">Ordering::AcqRel</span>) <span class="op">&</span> <span class="ident">READ</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span>
{
<span class="comment">// If a thread is still using the slot, it will continue destruction of the block.</span>
<span class="kw">return</span>;
}
}
<span class="comment">// No thread is using the block, now it is safe to destroy it.</span>
<span class="ident">drop</span>(<span class="ident">Box::from_raw</span>(<span class="ident">this</span>));
}
}
<span class="doccomment">/// A position in a queue.</span>
<span class="kw">struct</span> <span class="ident">Position</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// The index in the queue.</span>
<span class="ident">index</span>: <span class="ident">AtomicUsize</span>,
<span class="doccomment">/// The block in the linked list.</span>
<span class="ident">block</span>: <span class="ident">AtomicPtr</span><span class="op"><</span><span class="ident">Block</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span>,
}
<span class="doccomment">/// An injector queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is a FIFO queue that can be shared among multiple threads. Task schedulers typically have</span>
<span class="doccomment">/// a single injector queue, which is the entry point for new tasks.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::{Injector, Steal};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let q = Injector::new();</span>
<span class="doccomment">/// q.push(1);</span>
<span class="doccomment">/// q.push(2);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(q.steal(), Steal::Success(1));</span>
<span class="doccomment">/// assert_eq!(q.steal(), Steal::Success(2));</span>
<span class="doccomment">/// assert_eq!(q.steal(), Steal::Empty);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Injector</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// The head of the queue.</span>
<span class="ident">head</span>: <span class="ident">CachePadded</span><span class="op"><</span><span class="ident">Position</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span>,
<span class="doccomment">/// The tail of the queue.</span>
<span class="ident">tail</span>: <span class="ident">CachePadded</span><span class="op"><</span><span class="ident">Position</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span>,
<span class="doccomment">/// Indicates that dropping a `Injector<T>` may drop values of type `T`.</span>
<span class="ident">_marker</span>: <span class="ident">PhantomData</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>,
}
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">Send</span> <span class="kw">for</span> <span class="ident">Injector</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">Sync</span> <span class="kw">for</span> <span class="ident">Injector</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Default</span> <span class="kw">for</span> <span class="ident">Injector</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">default</span>() <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="kw">let</span> <span class="ident">block</span> <span class="op">=</span> <span class="ident">Box::into_raw</span>(<span class="ident">Box::new</span>(<span class="ident">Block</span>::<span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="ident">::new</span>()));
<span class="self">Self</span> {
<span class="ident">head</span>: <span class="ident">CachePadded::new</span>(<span class="ident">Position</span> {
<span class="ident">block</span>: <span class="ident">AtomicPtr::new</span>(<span class="ident">block</span>),
<span class="ident">index</span>: <span class="ident">AtomicUsize::new</span>(<span class="number">0</span>),
}),
<span class="ident">tail</span>: <span class="ident">CachePadded::new</span>(<span class="ident">Position</span> {
<span class="ident">block</span>: <span class="ident">AtomicPtr::new</span>(<span class="ident">block</span>),
<span class="ident">index</span>: <span class="ident">AtomicUsize::new</span>(<span class="number">0</span>),
}),
<span class="ident">_marker</span>: <span class="ident">PhantomData</span>,
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Injector</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Creates a new injector queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Injector;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let q = Injector::<i32>::new();</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>() <span class="op">-</span><span class="op">></span> <span class="ident">Injector</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="self">Self</span><span class="ident">::default</span>()
}
<span class="doccomment">/// Pushes a task into the queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Injector;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Injector::new();</span>
<span class="doccomment">/// w.push(1);</span>
<span class="doccomment">/// w.push(2);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">push</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">task</span>: <span class="ident">T</span>) {
<span class="kw">let</span> <span class="ident">backoff</span> <span class="op">=</span> <span class="ident">Backoff::new</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">tail</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">block</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">block</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">next_block</span> <span class="op">=</span> <span class="prelude-val">None</span>;
<span class="kw">loop</span> {
<span class="comment">// Calculate the offset of the index into the block.</span>
<span class="kw">let</span> <span class="ident">offset</span> <span class="op">=</span> (<span class="ident">tail</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">%</span> <span class="ident">LAP</span>;
<span class="comment">// If we reached the end of the block, wait until the next one is installed.</span>
<span class="kw">if</span> <span class="ident">offset</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="ident">backoff</span>.<span class="ident">snooze</span>();
<span class="ident">tail</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="ident">block</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">block</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="kw">continue</span>;
}
<span class="comment">// If we're going to have to install the next block, allocate it in advance in order to</span>
<span class="comment">// make the wait for other threads as short as possible.</span>
<span class="kw">if</span> <span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> <span class="op">&&</span> <span class="ident">next_block</span>.<span class="ident">is_none</span>() {
<span class="ident">next_block</span> <span class="op">=</span> <span class="prelude-val">Some</span>(<span class="ident">Box::new</span>(<span class="ident">Block</span>::<span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="ident">::new</span>()));
}
<span class="kw">let</span> <span class="ident">new_tail</span> <span class="op">=</span> <span class="ident">tail</span> <span class="op">+</span> (<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
<span class="comment">// Try advancing the tail forward.</span>
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">compare_exchange_weak</span>(
<span class="ident">tail</span>,
<span class="ident">new_tail</span>,
<span class="ident">Ordering::SeqCst</span>,
<span class="ident">Ordering::Acquire</span>,
) {
<span class="prelude-val">Ok</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="kw">unsafe</span> {
<span class="comment">// If we've reached the end of the block, install the next one.</span>
<span class="kw">if</span> <span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="kw">let</span> <span class="ident">next_block</span> <span class="op">=</span> <span class="ident">Box::into_raw</span>(<span class="ident">next_block</span>.<span class="ident">unwrap</span>());
<span class="kw">let</span> <span class="ident">next_index</span> <span class="op">=</span> <span class="ident">new_tail</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
<span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">block</span>.<span class="ident">store</span>(<span class="ident">next_block</span>, <span class="ident">Ordering::Release</span>);
<span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">store</span>(<span class="ident">next_index</span>, <span class="ident">Ordering::Release</span>);
(<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">next</span>.<span class="ident">store</span>(<span class="ident">next_block</span>, <span class="ident">Ordering::Release</span>);
}
<span class="comment">// Write the task into the slot.</span>
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">offset</span>);
<span class="ident">slot</span>.<span class="ident">task</span>.<span class="ident">get</span>().<span class="ident">write</span>(<span class="ident">MaybeUninit::new</span>(<span class="ident">task</span>));
<span class="ident">slot</span>.<span class="ident">state</span>.<span class="ident">fetch_or</span>(<span class="ident">WRITE</span>, <span class="ident">Ordering::Release</span>);
<span class="kw">return</span>;
},
<span class="prelude-val">Err</span>(<span class="ident">t</span>) <span class="op">=</span><span class="op">></span> {
<span class="ident">tail</span> <span class="op">=</span> <span class="ident">t</span>;
<span class="ident">block</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">block</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="ident">backoff</span>.<span class="ident">spin</span>();
}
}
}
}
<span class="doccomment">/// Steals a task from the queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::{Injector, Steal};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let q = Injector::new();</span>
<span class="doccomment">/// q.push(1);</span>
<span class="doccomment">/// q.push(2);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(q.steal(), Steal::Success(1));</span>
<span class="doccomment">/// assert_eq!(q.steal(), Steal::Success(2));</span>
<span class="doccomment">/// assert_eq!(q.steal(), Steal::Empty);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">steal</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">head</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">block</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">offset</span>;
<span class="kw">let</span> <span class="ident">backoff</span> <span class="op">=</span> <span class="ident">Backoff::new</span>();
<span class="kw">loop</span> {
<span class="ident">head</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="ident">block</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">block</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// Calculate the offset of the index into the block.</span>
<span class="ident">offset</span> <span class="op">=</span> (<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">%</span> <span class="ident">LAP</span>;
<span class="comment">// If we reached the end of the block, wait until the next one is installed.</span>
<span class="kw">if</span> <span class="ident">offset</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="ident">backoff</span>.<span class="ident">snooze</span>();
} <span class="kw">else</span> {
<span class="kw">break</span>;
}
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">new_head</span> <span class="op">=</span> <span class="ident">head</span> <span class="op">+</span> (<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
<span class="kw">if</span> <span class="ident">new_head</span> <span class="op">&</span> <span class="ident">HAS_NEXT</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="kw">let</span> <span class="ident">tail</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="comment">// If the tail equals the head, that means the queue is empty.</span>
<span class="kw">if</span> <span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span> <span class="op">=</span><span class="op">=</span> <span class="ident">tail</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span> {
<span class="kw">return</span> <span class="ident">Steal::Empty</span>;
}
<span class="comment">// If head and tail are not in the same block, set `HAS_NEXT` in head.</span>
<span class="kw">if</span> (<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">/</span> <span class="ident">LAP</span> <span class="op">!</span><span class="op">=</span> (<span class="ident">tail</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">/</span> <span class="ident">LAP</span> {
<span class="ident">new_head</span> <span class="op">|</span><span class="op">=</span> <span class="ident">HAS_NEXT</span>;
}
}
<span class="comment">// Try moving the head index forward.</span>
<span class="kw">if</span> <span class="self">self</span>
.<span class="ident">head</span>
.<span class="ident">index</span>
.<span class="ident">compare_exchange_weak</span>(<span class="ident">head</span>, <span class="ident">new_head</span>, <span class="ident">Ordering::SeqCst</span>, <span class="ident">Ordering::Acquire</span>)
.<span class="ident">is_err</span>()
{
<span class="kw">return</span> <span class="ident">Steal::Retry</span>;
}
<span class="kw">unsafe</span> {
<span class="comment">// If we've reached the end of the block, move to the next one.</span>
<span class="kw">if</span> <span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="kw">let</span> <span class="ident">next</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">wait_next</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">next_index</span> <span class="op">=</span> (<span class="ident">new_head</span> <span class="op">&</span> <span class="op">!</span><span class="ident">HAS_NEXT</span>).<span class="ident">wrapping_add</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
<span class="kw">if</span> <span class="op">!</span>(<span class="kw-2">*</span><span class="ident">next</span>).<span class="ident">next</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>).<span class="ident">is_null</span>() {
<span class="ident">next_index</span> <span class="op">|</span><span class="op">=</span> <span class="ident">HAS_NEXT</span>;
}
<span class="self">self</span>.<span class="ident">head</span>.<span class="ident">block</span>.<span class="ident">store</span>(<span class="ident">next</span>, <span class="ident">Ordering::Release</span>);
<span class="self">self</span>.<span class="ident">head</span>.<span class="ident">index</span>.<span class="ident">store</span>(<span class="ident">next_index</span>, <span class="ident">Ordering::Release</span>);
}
<span class="comment">// Read the task.</span>
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">offset</span>);
<span class="ident">slot</span>.<span class="ident">wait_write</span>();
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">slot</span>.<span class="ident">task</span>.<span class="ident">get</span>().<span class="ident">read</span>().<span class="ident">assume_init</span>();
<span class="comment">// Destroy the block if we've reached the end, or if another thread wanted to destroy</span>
<span class="comment">// but couldn't because we were busy reading from the slot.</span>
<span class="kw">if</span> (<span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span>)
<span class="op">|</span><span class="op">|</span> (<span class="ident">slot</span>.<span class="ident">state</span>.<span class="ident">fetch_or</span>(<span class="ident">READ</span>, <span class="ident">Ordering::AcqRel</span>) <span class="op">&</span> <span class="ident">DESTROY</span> <span class="op">!</span><span class="op">=</span> <span class="number">0</span>)
{
<span class="ident">Block::destroy</span>(<span class="ident">block</span>, <span class="ident">offset</span>);
}
<span class="ident">Steal::Success</span>(<span class="ident">task</span>)
}
}
<span class="doccomment">/// Steals a batch of tasks and pushes them into a worker.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// How many tasks exactly will be stolen is not specified. That said, this method will try to</span>
<span class="doccomment">/// steal around half of the tasks in the queue, but also not more than some constant limit.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::{Injector, Worker};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let q = Injector::new();</span>
<span class="doccomment">/// q.push(1);</span>
<span class="doccomment">/// q.push(2);</span>
<span class="doccomment">/// q.push(3);</span>
<span class="doccomment">/// q.push(4);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_fifo();</span>
<span class="doccomment">/// let _ = q.steal_batch(&w);</span>
<span class="doccomment">/// assert_eq!(w.pop(), Some(1));</span>
<span class="doccomment">/// assert_eq!(w.pop(), Some(2));</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">steal_batch</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">dest</span>: <span class="kw-2">&</span><span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span>()<span class="op">></span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">head</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">block</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">offset</span>;
<span class="kw">let</span> <span class="ident">backoff</span> <span class="op">=</span> <span class="ident">Backoff::new</span>();
<span class="kw">loop</span> {
<span class="ident">head</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="ident">block</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">block</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// Calculate the offset of the index into the block.</span>
<span class="ident">offset</span> <span class="op">=</span> (<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">%</span> <span class="ident">LAP</span>;
<span class="comment">// If we reached the end of the block, wait until the next one is installed.</span>
<span class="kw">if</span> <span class="ident">offset</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="ident">backoff</span>.<span class="ident">snooze</span>();
} <span class="kw">else</span> {
<span class="kw">break</span>;
}
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">new_head</span> <span class="op">=</span> <span class="ident">head</span>;
<span class="kw">let</span> <span class="ident">advance</span>;
<span class="kw">if</span> <span class="ident">new_head</span> <span class="op">&</span> <span class="ident">HAS_NEXT</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="kw">let</span> <span class="ident">tail</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="comment">// If the tail equals the head, that means the queue is empty.</span>
<span class="kw">if</span> <span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span> <span class="op">=</span><span class="op">=</span> <span class="ident">tail</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span> {
<span class="kw">return</span> <span class="ident">Steal::Empty</span>;
}
<span class="comment">// If head and tail are not in the same block, set `HAS_NEXT` in head. Also, calculate</span>
<span class="comment">// the right batch size to steal.</span>
<span class="kw">if</span> (<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">/</span> <span class="ident">LAP</span> <span class="op">!</span><span class="op">=</span> (<span class="ident">tail</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">/</span> <span class="ident">LAP</span> {
<span class="ident">new_head</span> <span class="op">|</span><span class="op">=</span> <span class="ident">HAS_NEXT</span>;
<span class="comment">// We can steal all tasks till the end of the block.</span>
<span class="ident">advance</span> <span class="op">=</span> (<span class="ident">BLOCK_CAP</span> <span class="op">-</span> <span class="ident">offset</span>).<span class="ident">min</span>(<span class="ident">MAX_BATCH</span>);
} <span class="kw">else</span> {
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> (<span class="ident">tail</span> <span class="op">-</span> <span class="ident">head</span>) <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>;
<span class="comment">// Steal half of the available tasks.</span>
<span class="ident">advance</span> <span class="op">=</span> ((<span class="ident">len</span> <span class="op">+</span> <span class="number">1</span>) <span class="op">/</span> <span class="number">2</span>).<span class="ident">min</span>(<span class="ident">MAX_BATCH</span>);
}
} <span class="kw">else</span> {
<span class="comment">// We can steal all tasks till the end of the block.</span>
<span class="ident">advance</span> <span class="op">=</span> (<span class="ident">BLOCK_CAP</span> <span class="op">-</span> <span class="ident">offset</span>).<span class="ident">min</span>(<span class="ident">MAX_BATCH</span>);
}
<span class="ident">new_head</span> <span class="op">+</span><span class="op">=</span> <span class="ident">advance</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>;
<span class="kw">let</span> <span class="ident">new_offset</span> <span class="op">=</span> <span class="ident">offset</span> <span class="op">+</span> <span class="ident">advance</span>;
<span class="comment">// Try moving the head index forward.</span>
<span class="kw">if</span> <span class="self">self</span>
.<span class="ident">head</span>
.<span class="ident">index</span>
.<span class="ident">compare_exchange_weak</span>(<span class="ident">head</span>, <span class="ident">new_head</span>, <span class="ident">Ordering::SeqCst</span>, <span class="ident">Ordering::Acquire</span>)
.<span class="ident">is_err</span>()
{
<span class="kw">return</span> <span class="ident">Steal::Retry</span>;
}
<span class="comment">// Reserve capacity for the stolen batch.</span>
<span class="kw">let</span> <span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">new_offset</span> <span class="op">-</span> <span class="ident">offset</span>;
<span class="ident">dest</span>.<span class="ident">reserve</span>(<span class="ident">batch_size</span>);
<span class="comment">// Get the destination buffer and back index.</span>
<span class="kw">let</span> <span class="ident">dest_buffer</span> <span class="op">=</span> <span class="ident">dest</span>.<span class="ident">buffer</span>.<span class="ident">get</span>();
<span class="kw">let</span> <span class="ident">dest_b</span> <span class="op">=</span> <span class="ident">dest</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">unsafe</span> {
<span class="comment">// If we've reached the end of the block, move to the next one.</span>
<span class="kw">if</span> <span class="ident">new_offset</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="kw">let</span> <span class="ident">next</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">wait_next</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">next_index</span> <span class="op">=</span> (<span class="ident">new_head</span> <span class="op">&</span> <span class="op">!</span><span class="ident">HAS_NEXT</span>).<span class="ident">wrapping_add</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
<span class="kw">if</span> <span class="op">!</span>(<span class="kw-2">*</span><span class="ident">next</span>).<span class="ident">next</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>).<span class="ident">is_null</span>() {
<span class="ident">next_index</span> <span class="op">|</span><span class="op">=</span> <span class="ident">HAS_NEXT</span>;
}
<span class="self">self</span>.<span class="ident">head</span>.<span class="ident">block</span>.<span class="ident">store</span>(<span class="ident">next</span>, <span class="ident">Ordering::Release</span>);
<span class="self">self</span>.<span class="ident">head</span>.<span class="ident">index</span>.<span class="ident">store</span>(<span class="ident">next_index</span>, <span class="ident">Ordering::Release</span>);
}
<span class="comment">// Copy values from the injector into the destination queue.</span>
<span class="kw">match</span> <span class="ident">dest</span>.<span class="ident">flavor</span> {
<span class="ident">Flavor::Fifo</span> <span class="op">=</span><span class="op">></span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> {
<span class="comment">// Read the task.</span>
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">offset</span> <span class="op">+</span> <span class="ident">i</span>);
<span class="ident">slot</span>.<span class="ident">wait_write</span>();
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">slot</span>.<span class="ident">task</span>.<span class="ident">get</span>().<span class="ident">read</span>().<span class="ident">assume_init</span>();
<span class="comment">// Write it into the destination queue.</span>
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">i</span> <span class="kw">as</span> <span class="ident">isize</span>), <span class="ident">task</span>);
}
}
<span class="ident">Flavor::Lifo</span> <span class="op">=</span><span class="op">></span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> {
<span class="comment">// Read the task.</span>
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">offset</span> <span class="op">+</span> <span class="ident">i</span>);
<span class="ident">slot</span>.<span class="ident">wait_write</span>();
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">slot</span>.<span class="ident">task</span>.<span class="ident">get</span>().<span class="ident">read</span>().<span class="ident">assume_init</span>();
<span class="comment">// Write it into the destination queue.</span>
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>((<span class="ident">batch_size</span> <span class="op">-</span> <span class="number">1</span> <span class="op">-</span> <span class="ident">i</span>) <span class="kw">as</span> <span class="ident">isize</span>), <span class="ident">task</span>);
}
}
}
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::Release</span>);
<span class="comment">// Update the back index in the destination queue.</span>
<span class="comment">//</span>
<span class="comment">// This ordering could be `Relaxed`, but then thread sanitizer would falsely report</span>
<span class="comment">// data races because it doesn't understand fences.</span>
<span class="ident">dest</span>.<span class="ident">inner</span>
.<span class="ident">back</span>
.<span class="ident">store</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">batch_size</span> <span class="kw">as</span> <span class="ident">isize</span>), <span class="ident">Ordering::Release</span>);
<span class="comment">// Destroy the block if we've reached the end, or if another thread wanted to destroy</span>
<span class="comment">// but couldn't because we were busy reading from the slot.</span>
<span class="kw">if</span> <span class="ident">new_offset</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="ident">Block::destroy</span>(<span class="ident">block</span>, <span class="ident">offset</span>);
} <span class="kw">else</span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="ident">offset</span>..<span class="ident">new_offset</span> {
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>);
<span class="kw">if</span> <span class="ident">slot</span>.<span class="ident">state</span>.<span class="ident">fetch_or</span>(<span class="ident">READ</span>, <span class="ident">Ordering::AcqRel</span>) <span class="op">&</span> <span class="ident">DESTROY</span> <span class="op">!</span><span class="op">=</span> <span class="number">0</span> {
<span class="ident">Block::destroy</span>(<span class="ident">block</span>, <span class="ident">offset</span>);
<span class="kw">break</span>;
}
}
}
<span class="ident">Steal::Success</span>(())
}
}
<span class="doccomment">/// Steals a batch of tasks, pushes them into a worker, and pops a task from that worker.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// How many tasks exactly will be stolen is not specified. That said, this method will try to</span>
<span class="doccomment">/// steal around half of the tasks in the queue, but also not more than some constant limit.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::{Injector, Steal, Worker};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let q = Injector::new();</span>
<span class="doccomment">/// q.push(1);</span>
<span class="doccomment">/// q.push(2);</span>
<span class="doccomment">/// q.push(3);</span>
<span class="doccomment">/// q.push(4);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let w = Worker::new_fifo();</span>
<span class="doccomment">/// assert_eq!(q.steal_batch_and_pop(&w), Steal::Success(1));</span>
<span class="doccomment">/// assert_eq!(w.pop(), Some(2));</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">steal_batch_and_pop</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">dest</span>: <span class="kw-2">&</span><span class="ident">Worker</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">head</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">block</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">offset</span>;
<span class="kw">let</span> <span class="ident">backoff</span> <span class="op">=</span> <span class="ident">Backoff::new</span>();
<span class="kw">loop</span> {
<span class="ident">head</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="ident">block</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">block</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>);
<span class="comment">// Calculate the offset of the index into the block.</span>
<span class="ident">offset</span> <span class="op">=</span> (<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">%</span> <span class="ident">LAP</span>;
<span class="comment">// If we reached the end of the block, wait until the next one is installed.</span>
<span class="kw">if</span> <span class="ident">offset</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="ident">backoff</span>.<span class="ident">snooze</span>();
} <span class="kw">else</span> {
<span class="kw">break</span>;
}
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">new_head</span> <span class="op">=</span> <span class="ident">head</span>;
<span class="kw">let</span> <span class="ident">advance</span>;
<span class="kw">if</span> <span class="ident">new_head</span> <span class="op">&</span> <span class="ident">HAS_NEXT</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="kw">let</span> <span class="ident">tail</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="comment">// If the tail equals the head, that means the queue is empty.</span>
<span class="kw">if</span> <span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span> <span class="op">=</span><span class="op">=</span> <span class="ident">tail</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span> {
<span class="kw">return</span> <span class="ident">Steal::Empty</span>;
}
<span class="comment">// If head and tail are not in the same block, set `HAS_NEXT` in head.</span>
<span class="kw">if</span> (<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">/</span> <span class="ident">LAP</span> <span class="op">!</span><span class="op">=</span> (<span class="ident">tail</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">/</span> <span class="ident">LAP</span> {
<span class="ident">new_head</span> <span class="op">|</span><span class="op">=</span> <span class="ident">HAS_NEXT</span>;
<span class="comment">// We can steal all tasks till the end of the block.</span>
<span class="ident">advance</span> <span class="op">=</span> (<span class="ident">BLOCK_CAP</span> <span class="op">-</span> <span class="ident">offset</span>).<span class="ident">min</span>(<span class="ident">MAX_BATCH</span> <span class="op">+</span> <span class="number">1</span>);
} <span class="kw">else</span> {
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> (<span class="ident">tail</span> <span class="op">-</span> <span class="ident">head</span>) <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>;
<span class="comment">// Steal half of the available tasks.</span>
<span class="ident">advance</span> <span class="op">=</span> ((<span class="ident">len</span> <span class="op">+</span> <span class="number">1</span>) <span class="op">/</span> <span class="number">2</span>).<span class="ident">min</span>(<span class="ident">MAX_BATCH</span> <span class="op">+</span> <span class="number">1</span>);
}
} <span class="kw">else</span> {
<span class="comment">// We can steal all tasks till the end of the block.</span>
<span class="ident">advance</span> <span class="op">=</span> (<span class="ident">BLOCK_CAP</span> <span class="op">-</span> <span class="ident">offset</span>).<span class="ident">min</span>(<span class="ident">MAX_BATCH</span> <span class="op">+</span> <span class="number">1</span>);
}
<span class="ident">new_head</span> <span class="op">+</span><span class="op">=</span> <span class="ident">advance</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>;
<span class="kw">let</span> <span class="ident">new_offset</span> <span class="op">=</span> <span class="ident">offset</span> <span class="op">+</span> <span class="ident">advance</span>;
<span class="comment">// Try moving the head index forward.</span>
<span class="kw">if</span> <span class="self">self</span>
.<span class="ident">head</span>
.<span class="ident">index</span>
.<span class="ident">compare_exchange_weak</span>(<span class="ident">head</span>, <span class="ident">new_head</span>, <span class="ident">Ordering::SeqCst</span>, <span class="ident">Ordering::Acquire</span>)
.<span class="ident">is_err</span>()
{
<span class="kw">return</span> <span class="ident">Steal::Retry</span>;
}
<span class="comment">// Reserve capacity for the stolen batch.</span>
<span class="kw">let</span> <span class="ident">batch_size</span> <span class="op">=</span> <span class="ident">new_offset</span> <span class="op">-</span> <span class="ident">offset</span> <span class="op">-</span> <span class="number">1</span>;
<span class="ident">dest</span>.<span class="ident">reserve</span>(<span class="ident">batch_size</span>);
<span class="comment">// Get the destination buffer and back index.</span>
<span class="kw">let</span> <span class="ident">dest_buffer</span> <span class="op">=</span> <span class="ident">dest</span>.<span class="ident">buffer</span>.<span class="ident">get</span>();
<span class="kw">let</span> <span class="ident">dest_b</span> <span class="op">=</span> <span class="ident">dest</span>.<span class="ident">inner</span>.<span class="ident">back</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">unsafe</span> {
<span class="comment">// If we've reached the end of the block, move to the next one.</span>
<span class="kw">if</span> <span class="ident">new_offset</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="kw">let</span> <span class="ident">next</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">wait_next</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">next_index</span> <span class="op">=</span> (<span class="ident">new_head</span> <span class="op">&</span> <span class="op">!</span><span class="ident">HAS_NEXT</span>).<span class="ident">wrapping_add</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
<span class="kw">if</span> <span class="op">!</span>(<span class="kw-2">*</span><span class="ident">next</span>).<span class="ident">next</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>).<span class="ident">is_null</span>() {
<span class="ident">next_index</span> <span class="op">|</span><span class="op">=</span> <span class="ident">HAS_NEXT</span>;
}
<span class="self">self</span>.<span class="ident">head</span>.<span class="ident">block</span>.<span class="ident">store</span>(<span class="ident">next</span>, <span class="ident">Ordering::Release</span>);
<span class="self">self</span>.<span class="ident">head</span>.<span class="ident">index</span>.<span class="ident">store</span>(<span class="ident">next_index</span>, <span class="ident">Ordering::Release</span>);
}
<span class="comment">// Read the task.</span>
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">offset</span>);
<span class="ident">slot</span>.<span class="ident">wait_write</span>();
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">slot</span>.<span class="ident">task</span>.<span class="ident">get</span>().<span class="ident">read</span>().<span class="ident">assume_init</span>();
<span class="kw">match</span> <span class="ident">dest</span>.<span class="ident">flavor</span> {
<span class="ident">Flavor::Fifo</span> <span class="op">=</span><span class="op">></span> {
<span class="comment">// Copy values from the injector into the destination queue.</span>
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> {
<span class="comment">// Read the task.</span>
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">offset</span> <span class="op">+</span> <span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>);
<span class="ident">slot</span>.<span class="ident">wait_write</span>();
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">slot</span>.<span class="ident">task</span>.<span class="ident">get</span>().<span class="ident">read</span>().<span class="ident">assume_init</span>();
<span class="comment">// Write it into the destination queue.</span>
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">i</span> <span class="kw">as</span> <span class="ident">isize</span>), <span class="ident">task</span>);
}
}
<span class="ident">Flavor::Lifo</span> <span class="op">=</span><span class="op">></span> {
<span class="comment">// Copy values from the injector into the destination queue.</span>
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">batch_size</span> {
<span class="comment">// Read the task.</span>
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">offset</span> <span class="op">+</span> <span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>);
<span class="ident">slot</span>.<span class="ident">wait_write</span>();
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">slot</span>.<span class="ident">task</span>.<span class="ident">get</span>().<span class="ident">read</span>().<span class="ident">assume_init</span>();
<span class="comment">// Write it into the destination queue.</span>
<span class="ident">dest_buffer</span>.<span class="ident">write</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>((<span class="ident">batch_size</span> <span class="op">-</span> <span class="number">1</span> <span class="op">-</span> <span class="ident">i</span>) <span class="kw">as</span> <span class="ident">isize</span>), <span class="ident">task</span>);
}
}
}
<span class="ident">atomic::fence</span>(<span class="ident">Ordering::Release</span>);
<span class="comment">// Update the back index in the destination queue.</span>
<span class="comment">//</span>
<span class="comment">// This ordering could be `Relaxed`, but then thread sanitizer would falsely report</span>
<span class="comment">// data races because it doesn't understand fences.</span>
<span class="ident">dest</span>.<span class="ident">inner</span>
.<span class="ident">back</span>
.<span class="ident">store</span>(<span class="ident">dest_b</span>.<span class="ident">wrapping_add</span>(<span class="ident">batch_size</span> <span class="kw">as</span> <span class="ident">isize</span>), <span class="ident">Ordering::Release</span>);
<span class="comment">// Destroy the block if we've reached the end, or if another thread wanted to destroy</span>
<span class="comment">// but couldn't because we were busy reading from the slot.</span>
<span class="kw">if</span> <span class="ident">new_offset</span> <span class="op">=</span><span class="op">=</span> <span class="ident">BLOCK_CAP</span> {
<span class="ident">Block::destroy</span>(<span class="ident">block</span>, <span class="ident">offset</span>);
} <span class="kw">else</span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="ident">offset</span>..<span class="ident">new_offset</span> {
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>);
<span class="kw">if</span> <span class="ident">slot</span>.<span class="ident">state</span>.<span class="ident">fetch_or</span>(<span class="ident">READ</span>, <span class="ident">Ordering::AcqRel</span>) <span class="op">&</span> <span class="ident">DESTROY</span> <span class="op">!</span><span class="op">=</span> <span class="number">0</span> {
<span class="ident">Block::destroy</span>(<span class="ident">block</span>, <span class="ident">offset</span>);
<span class="kw">break</span>;
}
}
}
<span class="ident">Steal::Success</span>(<span class="ident">task</span>)
}
}
<span class="doccomment">/// Returns `true` if the queue is empty.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Injector;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let q = Injector::new();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert!(q.is_empty());</span>
<span class="doccomment">/// q.push(1);</span>
<span class="doccomment">/// assert!(!q.is_empty());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">let</span> <span class="ident">head</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="kw">let</span> <span class="ident">tail</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span> <span class="op">=</span><span class="op">=</span> <span class="ident">tail</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>
}
<span class="doccomment">/// Returns the number of tasks in the queue.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Injector;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let q = Injector::new();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(q.len(), 0);</span>
<span class="doccomment">/// q.push(1);</span>
<span class="doccomment">/// assert_eq!(q.len(), 1);</span>
<span class="doccomment">/// q.push(1);</span>
<span class="doccomment">/// assert_eq!(q.len(), 2);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">len</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">usize</span> {
<span class="kw">loop</span> {
<span class="comment">// Load the tail index, then load the head index.</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">tail</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">head</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="comment">// If the tail index didn't change, we've got consistent indices to work with.</span>
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>) <span class="op">=</span><span class="op">=</span> <span class="ident">tail</span> {
<span class="comment">// Erase the lower bits.</span>
<span class="ident">tail</span> <span class="op">&=</span> <span class="op">!</span>((<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>) <span class="op">-</span> <span class="number">1</span>);
<span class="ident">head</span> <span class="op">&=</span> <span class="op">!</span>((<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>) <span class="op">-</span> <span class="number">1</span>);
<span class="comment">// Fix up indices if they fall onto block ends.</span>
<span class="kw">if</span> (<span class="ident">tail</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">&</span> (<span class="ident">LAP</span> <span class="op">-</span> <span class="number">1</span>) <span class="op">=</span><span class="op">=</span> <span class="ident">LAP</span> <span class="op">-</span> <span class="number">1</span> {
<span class="ident">tail</span> <span class="op">=</span> <span class="ident">tail</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
}
<span class="kw">if</span> (<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">&</span> (<span class="ident">LAP</span> <span class="op">-</span> <span class="number">1</span>) <span class="op">=</span><span class="op">=</span> <span class="ident">LAP</span> <span class="op">-</span> <span class="number">1</span> {
<span class="ident">head</span> <span class="op">=</span> <span class="ident">head</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
}
<span class="comment">// Rotate indices so that head falls into the first block.</span>
<span class="kw">let</span> <span class="ident">lap</span> <span class="op">=</span> (<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">/</span> <span class="ident">LAP</span>;
<span class="ident">tail</span> <span class="op">=</span> <span class="ident">tail</span>.<span class="ident">wrapping_sub</span>((<span class="ident">lap</span> <span class="op">*</span> <span class="ident">LAP</span>) <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
<span class="ident">head</span> <span class="op">=</span> <span class="ident">head</span>.<span class="ident">wrapping_sub</span>((<span class="ident">lap</span> <span class="op">*</span> <span class="ident">LAP</span>) <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
<span class="comment">// Remove the lower bits.</span>
<span class="ident">tail</span> <span class="op">></span><span class="op">></span><span class="op">=</span> <span class="ident">SHIFT</span>;
<span class="ident">head</span> <span class="op">></span><span class="op">></span><span class="op">=</span> <span class="ident">SHIFT</span>;
<span class="comment">// Return the difference minus the number of blocks between tail and head.</span>
<span class="kw">return</span> <span class="ident">tail</span> <span class="op">-</span> <span class="ident">head</span> <span class="op">-</span> <span class="ident">tail</span> <span class="op">/</span> <span class="ident">LAP</span>;
}
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">Injector</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">head</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">tail</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">tail</span>.<span class="ident">index</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">block</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">head</span>.<span class="ident">block</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="comment">// Erase the lower bits.</span>
<span class="ident">head</span> <span class="op">&=</span> <span class="op">!</span>((<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>) <span class="op">-</span> <span class="number">1</span>);
<span class="ident">tail</span> <span class="op">&=</span> <span class="op">!</span>((<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>) <span class="op">-</span> <span class="number">1</span>);
<span class="kw">unsafe</span> {
<span class="comment">// Drop all values between `head` and `tail` and deallocate the heap-allocated blocks.</span>
<span class="kw">while</span> <span class="ident">head</span> <span class="op">!</span><span class="op">=</span> <span class="ident">tail</span> {
<span class="kw">let</span> <span class="ident">offset</span> <span class="op">=</span> (<span class="ident">head</span> <span class="op">></span><span class="op">></span> <span class="ident">SHIFT</span>) <span class="op">%</span> <span class="ident">LAP</span>;
<span class="kw">if</span> <span class="ident">offset</span> <span class="op"><</span> <span class="ident">BLOCK_CAP</span> {
<span class="comment">// Drop the task in the slot.</span>
<span class="kw">let</span> <span class="ident">slot</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">slots</span>.<span class="ident">get_unchecked</span>(<span class="ident">offset</span>);
<span class="kw">let</span> <span class="ident">p</span> <span class="op">=</span> <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span><span class="ident">slot</span>.<span class="ident">task</span>.<span class="ident">get</span>();
<span class="ident">p</span>.<span class="ident">as_mut_ptr</span>().<span class="ident">drop_in_place</span>();
} <span class="kw">else</span> {
<span class="comment">// Deallocate the block and move to the next one.</span>
<span class="kw">let</span> <span class="ident">next</span> <span class="op">=</span> (<span class="kw-2">*</span><span class="ident">block</span>).<span class="ident">next</span>.<span class="ident">load</span>(<span class="ident">Ordering::Relaxed</span>);
<span class="ident">drop</span>(<span class="ident">Box::from_raw</span>(<span class="ident">block</span>));
<span class="ident">block</span> <span class="op">=</span> <span class="ident">next</span>;
}
<span class="ident">head</span> <span class="op">=</span> <span class="ident">head</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="ident">SHIFT</span>);
}
<span class="comment">// Deallocate the last remaining block.</span>
<span class="ident">drop</span>(<span class="ident">Box::from_raw</span>(<span class="ident">block</span>));
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">fmt::Debug</span> <span class="kw">for</span> <span class="ident">Injector</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt::Formatter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt::Result</span> {
<span class="ident">f</span>.<span class="ident">pad</span>(<span class="string">"Worker { .. }"</span>)
}
}
<span class="doccomment">/// Possible outcomes of a steal operation.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// There are lots of ways to chain results of steal operations together:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Steal::{self, Empty, Retry, Success};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let collect = |v: Vec<Steal<i32>>| v.into_iter().collect::<Steal<i32>>();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(collect(vec![Empty, Empty, Empty]), Empty);</span>
<span class="doccomment">/// assert_eq!(collect(vec![Empty, Retry, Empty]), Retry);</span>
<span class="doccomment">/// assert_eq!(collect(vec![Retry, Success(1), Empty]), Success(1));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(collect(vec![Empty, Empty]).or_else(|| Retry), Retry);</span>
<span class="doccomment">/// assert_eq!(collect(vec![Retry, Empty]).or_else(|| Success(1)), Success(1));</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">must_use</span>]</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">PartialEq</span>, <span class="ident">Eq</span>, <span class="ident">Copy</span>, <span class="ident">Clone</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// The queue was empty at the time of stealing.</span>
<span class="ident">Empty</span>,
<span class="doccomment">/// At least one task was successfully stolen.</span>
<span class="ident">Success</span>(<span class="ident">T</span>),
<span class="doccomment">/// The steal operation needs to be retried.</span>
<span class="ident">Retry</span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Returns `true` if the queue was empty at the time of stealing.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Steal::{Empty, Retry, Success};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert!(!Success(7).is_empty());</span>
<span class="doccomment">/// assert!(!Retry::<i32>.is_empty());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert!(Empty::<i32>.is_empty());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">Steal::Empty</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
}
}
<span class="doccomment">/// Returns `true` if at least one task was stolen.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Steal::{Empty, Retry, Success};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert!(!Empty::<i32>.is_success());</span>
<span class="doccomment">/// assert!(!Retry::<i32>.is_success());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert!(Success(7).is_success());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_success</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">Steal::Success</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
}
}
<span class="doccomment">/// Returns `true` if the steal operation needs to be retried.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Steal::{Empty, Retry, Success};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert!(!Empty::<i32>.is_retry());</span>
<span class="doccomment">/// assert!(!Success(7).is_retry());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert!(Retry::<i32>.is_retry());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_retry</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">Steal::Retry</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">true</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="bool-val">false</span>,
}
}
<span class="doccomment">/// Returns the result of the operation, if successful.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Steal::{Empty, Retry, Success};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Empty::<i32>.success(), None);</span>
<span class="doccomment">/// assert_eq!(Retry::<i32>.success(), None);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Success(7).success(), Some(7));</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">success</span>(<span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">Steal::Success</span>(<span class="ident">res</span>) <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">res</span>),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">None</span>,
}
}
<span class="doccomment">/// If no task was stolen, attempts another steal operation.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Returns this steal result if it is `Success`. Otherwise, closure `f` is invoked and then:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// * If the second steal resulted in `Success`, it is returned.</span>
<span class="doccomment">/// * If both steals were unsuccessful but any resulted in `Retry`, then `Retry` is returned.</span>
<span class="doccomment">/// * If both resulted in `None`, then `None` is returned.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_deque::Steal::{Empty, Retry, Success};</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Success(1).or_else(|| Success(2)), Success(1));</span>
<span class="doccomment">/// assert_eq!(Retry.or_else(|| Success(2)), Success(2));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Retry.or_else(|| Empty), Retry::<i32>);</span>
<span class="doccomment">/// assert_eq!(Empty.or_else(|| Retry), Retry::<i32>);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(Empty.or_else(|| Empty), Empty::<i32>);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">or_else</span><span class="op"><</span><span class="ident">F</span><span class="op">></span>(<span class="self">self</span>, <span class="ident">f</span>: <span class="ident">F</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>
<span class="kw">where</span>
<span class="ident">F</span>: <span class="ident">FnOnce</span>() <span class="op">-</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>,
{
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">Steal::Empty</span> <span class="op">=</span><span class="op">></span> <span class="ident">f</span>(),
<span class="ident">Steal::Success</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="self">self</span>,
<span class="ident">Steal::Retry</span> <span class="op">=</span><span class="op">></span> {
<span class="kw">if</span> <span class="kw">let</span> <span class="ident">Steal::Success</span>(<span class="ident">res</span>) <span class="op">=</span> <span class="ident">f</span>() {
<span class="ident">Steal::Success</span>(<span class="ident">res</span>)
} <span class="kw">else</span> {
<span class="ident">Steal::Retry</span>
}
}
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">fmt::Debug</span> <span class="kw">for</span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt::Formatter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt::Result</span> {
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">Steal::Empty</span> <span class="op">=</span><span class="op">></span> <span class="ident">f</span>.<span class="ident">pad</span>(<span class="string">"Empty"</span>),
<span class="ident">Steal::Success</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="ident">f</span>.<span class="ident">pad</span>(<span class="string">"Success(..)"</span>),
<span class="ident">Steal::Retry</span> <span class="op">=</span><span class="op">></span> <span class="ident">f</span>.<span class="ident">pad</span>(<span class="string">"Retry"</span>),
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">FromIterator</span><span class="op"><</span><span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span> <span class="kw">for</span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Consumes items until a `Success` is found and returns it.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If no `Success` was found, but there was at least one `Retry`, then returns `Retry`.</span>
<span class="doccomment">/// Otherwise, `Empty` is returned.</span>
<span class="kw">fn</span> <span class="ident">from_iter</span><span class="op"><</span><span class="ident">I</span><span class="op">></span>(<span class="ident">iter</span>: <span class="ident">I</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>
<span class="kw">where</span>
<span class="ident">I</span>: <span class="ident">IntoIterator</span><span class="op"><</span><span class="ident">Item</span> <span class="op">=</span> <span class="ident">Steal</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span>,
{
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">retry</span> <span class="op">=</span> <span class="bool-val">false</span>;
<span class="kw">for</span> <span class="ident">s</span> <span class="kw">in</span> <span class="ident">iter</span> {
<span class="kw">match</span> <span class="kw-2">&</span><span class="ident">s</span> {
<span class="ident">Steal::Empty</span> <span class="op">=</span><span class="op">></span> {}
<span class="ident">Steal::Success</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="kw">return</span> <span class="ident">s</span>,
<span class="ident">Steal::Retry</span> <span class="op">=</span><span class="op">></span> <span class="ident">retry</span> <span class="op">=</span> <span class="bool-val">true</span>,
}
}
<span class="kw">if</span> <span class="ident">retry</span> {
<span class="ident">Steal::Retry</span>
} <span class="kw">else</span> {
<span class="ident">Steal::Empty</span>
}
}
}
</pre></div>
</section><section id="search" class="content hidden"></section><div id="rustdoc-vars" data-root-path="../../" data-current-crate="crossbeam_deque" data-search-index-js="../../search-index.js" data-search-js="../../search.js"></div><script src="../../main.js"></script><script src="../../source-script.js"></script><script src="../../source-files.js"></script></body></html>