<!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 `src/mutex.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>mutex.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><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 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../spin_sync/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"><img src="../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices" role="menu"></div></div><script src="../../theme.js"></script><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><span class="help-button">?</span>
<a id="settings-menu" href="../../settings.html"><img src="../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><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>
</pre><div class="example-wrap"><pre class="rust ">
<span class="comment">// Copyright 2020 Shin Yoshida</span>
<span class="comment">//</span>
<span class="comment">// "LGPL-3.0-or-later OR Apache-2.0 OR BSD-2-Clause"</span>
<span class="comment">//</span>
<span class="comment">// This is part of spin-sync</span>
<span class="comment">//</span>
<span class="comment">// spin-sync is free software: you can redistribute it and/or modify</span>
<span class="comment">// it under the terms of the GNU Lesser General Public License as published by</span>
<span class="comment">// the Free Software Foundation, either version 3 of the License, or</span>
<span class="comment">// (at your option) any later version.</span>
<span class="comment">//</span>
<span class="comment">// spin-sync is distributed in the hope that it will be useful,</span>
<span class="comment">// but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<span class="comment">// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</span>
<span class="comment">// GNU Lesser General Public License for more details.</span>
<span class="comment">//</span>
<span class="comment">// You should have received a copy of the GNU Lesser General Public License</span>
<span class="comment">// along with spin-sync. If not, see <http://www.gnu.org/licenses/>.</span>
<span class="comment">//</span>
<span class="comment">//</span>
<span class="comment">// Licensed under the Apache License, Version 2.0 (the "License");</span>
<span class="comment">// you may not use this file except in compliance with the License.</span>
<span class="comment">// You may obtain a copy of the License at</span>
<span class="comment">//</span>
<span class="comment">// http://www.apache.org/licenses/LICENSE-2.0</span>
<span class="comment">//</span>
<span class="comment">// Unless required by applicable law or agreed to in writing, software</span>
<span class="comment">// distributed under the License is distributed on an "AS IS" BASIS,</span>
<span class="comment">// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span>
<span class="comment">// See the License for the specific language governing permissions and</span>
<span class="comment">// limitations under the License.</span>
<span class="comment">//</span>
<span class="comment">//</span>
<span class="comment">// Redistribution and use in source and binary forms, with or without modification, are permitted</span>
<span class="comment">// provided that the following conditions are met:</span>
<span class="comment">//</span>
<span class="comment">// 1. Redistributions of source code must retain the above copyright notice, this list of</span>
<span class="comment">// conditions and the following disclaimer.</span>
<span class="comment">// 2. Redistributions in binary form must reproduce the above copyright notice, this</span>
<span class="comment">// list of conditions and the following disclaimer in the documentation and/or other</span>
<span class="comment">// materials provided with the distribution.</span>
<span class="comment">//</span>
<span class="comment">// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND</span>
<span class="comment">// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED</span>
<span class="comment">// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.</span>
<span class="comment">// IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,</span>
<span class="comment">// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT</span>
<span class="comment">// NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR</span>
<span class="comment">// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,</span>
<span class="comment">// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)</span>
<span class="comment">// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE</span>
<span class="comment">// POSSIBILITY OF SUCH DAMAGE.</span>
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">cell</span>::<span class="ident">UnsafeCell</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">fmt</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">ops</span>::{<span class="ident">Deref</span>, <span class="ident">DerefMut</span>};
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">panic</span>::{<span class="ident">RefUnwindSafe</span>, <span class="ident">UnwindSafe</span>};
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">sync</span>::<span class="ident">atomic</span>::{<span class="ident">AtomicU8</span>, <span class="ident">Ordering</span>};
<span class="kw">use</span> <span class="kw">crate</span>::<span class="ident">misc</span>::{<span class="ident">PhantomMutex</span>, <span class="ident">PhantomMutexGuard</span>};
<span class="kw">use</span> <span class="kw">crate</span>::<span class="ident">result</span>::{<span class="ident">LockResult</span>, <span class="ident">PoisonError</span>, <span class="ident">TryLockError</span>, <span class="ident">TryLockResult</span>};
<span class="doccomment">/// A mutual exclusion primitive useful for protecting shared data.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// It behaves like std::sync::Mutex except for using spinlock.</span>
<span class="doccomment">/// What is more, the constructor is a const function; i.e. it is possible to declare</span>
<span class="doccomment">/// static Mutex<T> variable as long as the inner data can be built statically.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This mutex will block threads waiting for the lock to become available. The</span>
<span class="doccomment">/// mutex can also be statically initialized or created via a [`new`]</span>
<span class="doccomment">/// constructor. Each mutex has a type parameter which represents the data that</span>
<span class="doccomment">/// it is protecting. The data can only be accessed through the RAII guards</span>
<span class="doccomment">/// returned from [`lock`] and [`try_lock`], which guarantees that the data is only</span>
<span class="doccomment">/// ever accessed when the mutex is locked.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Poisoning</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The mutexes in this module implement a strategy called "poisoning" where a</span>
<span class="doccomment">/// mutex is considered poisoned whenever a thread panics while holding the</span>
<span class="doccomment">/// mutex. Once a mutex is poisoned, all other threads are unable to access the</span>
<span class="doccomment">/// data by default as it is likely tainted.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// For a mutex, this means that the [`lock`] and [`try_lock`] methods return a</span>
<span class="doccomment">/// `Result` which indicates whether a mutex has been poisoned or not. Most</span>
<span class="doccomment">/// usage of a mutex will simply `unwrap()` these results, propagating panics</span>
<span class="doccomment">/// among threads to ensure that a possibly invalid invariant is not witnessed.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A poisoned mutex, however, does not prevent all access to the underlying</span>
<span class="doccomment">/// data. The [`PoisonError`] type has an `into_inner` method which will return</span>
<span class="doccomment">/// the guard that would have otherwise been returned on a successful lock. This</span>
<span class="doccomment">/// allows access to the data, despite the lock being poisoned.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`new`]: #method.new</span>
<span class="doccomment">/// [`lock`]: #method.lock</span>
<span class="doccomment">/// [`try_lock`]: #method.try_lock</span>
<span class="doccomment">/// [`PoisonError`]: type.PoisonError.html</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Protect a variable (non-atomically) and update it in worker threads.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use spin_sync::Mutex;</span>
<span class="doccomment">/// use std::thread;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// const WORKER_NUM: usize = 10;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // We can declare static Mutex<usize> variable because Mutex::new is const.</span>
<span class="doccomment">/// static MUTEX: Mutex<usize> = Mutex::new(0);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let mut handles = Vec::with_capacity(WORKER_NUM);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // Create worker threads to inclement the value by 1.</span>
<span class="doccomment">/// for _ in 0..WORKER_NUM {</span>
<span class="doccomment">/// let handle = thread::spawn(move || {</span>
<span class="doccomment">/// let mut num = MUTEX.lock().unwrap();</span>
<span class="doccomment">/// *num += 1;</span>
<span class="doccomment">/// });</span>
<span class="doccomment">///</span>
<span class="doccomment">/// handles.push(handle);</span>
<span class="doccomment">/// }</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // Wait for the all worker threads are finished.</span>
<span class="doccomment">/// for handle in handles {</span>
<span class="doccomment">/// handle.join().unwrap();</span>
<span class="doccomment">/// }</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // Make sure the value is incremented by the worker count.</span>
<span class="doccomment">/// let num = MUTEX.lock().unwrap();</span>
<span class="doccomment">/// assert_eq!(WORKER_NUM, *num);</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// To recover from a poisoned mutex:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use spin_sync::Mutex;</span>
<span class="doccomment">/// use std::sync::Arc;</span>
<span class="doccomment">/// use std::thread;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // Like std::sync::Mutex, it can be declare as local variable, of course.</span>
<span class="doccomment">/// let mutex = Arc::new(Mutex::new(0));</span>
<span class="doccomment">/// let c_mutex = mutex.clone();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let _ = thread::spawn(move || -> () {</span>
<span class="doccomment">/// // This thread will acquire the mutex first, unwrapping the result of</span>
<span class="doccomment">/// // `lock` because the lock has not been poisoned.</span>
<span class="doccomment">/// let _guard = c_mutex.lock().unwrap();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // This panic while holding the lock (`_guard` is in scope) will poison</span>
<span class="doccomment">/// // the mutex.</span>
<span class="doccomment">/// panic!();</span>
<span class="doccomment">/// }).join();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // Here, the mutex has been poisoned.</span>
<span class="doccomment">/// assert_eq!(true, mutex.is_poisoned());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // The returned result can be pattern matched on to return the underlying</span>
<span class="doccomment">/// // guard on both branches.</span>
<span class="doccomment">/// let mut guard = match mutex.lock() {</span>
<span class="doccomment">/// Ok(guard) => guard,</span>
<span class="doccomment">/// Err(poisoned) => poisoned.into_inner(),</span>
<span class="doccomment">/// };</span>
<span class="doccomment">///</span>
<span class="doccomment">/// *guard += 1;</span>
<span class="doccomment">/// assert_eq!(1, *guard);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Mutex</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> {
<span class="ident">lock</span>: <span class="ident">AtomicU8</span>,
<span class="ident">_phantom</span>: <span class="ident">PhantomMutex</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>,
<span class="ident">data</span>: <span class="ident">UnsafeCell</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">Mutex</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Creates a new mutex in an unlocked state ready for use.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// unlike to `std::sync::Mutex::new`, this is a const function.</span>
<span class="doccomment">/// It can be use for static variable.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Declare as a static variable.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use spin_sync::Mutex;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// static MUTEX: Mutex<i32> = Mutex::new(0);</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Declare as a local variable.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use spin_sync::Mutex;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let mutex = Mutex::new(0);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">const</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">t</span>: <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="ident">Mutex</span> {
<span class="ident">lock</span>: <span class="ident">AtomicU8</span>::<span class="ident">new</span>(<span class="ident">INIT</span>),
<span class="ident">data</span>: <span class="ident">UnsafeCell</span>::<span class="ident">new</span>(<span class="ident">t</span>),
<span class="ident">_phantom</span>: <span class="ident">PhantomMutex</span> {},
}
}
<span class="doccomment">/// Consumes this mutex and returns the underlying data.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that this method won't acquire any lock because we know there is</span>
<span class="doccomment">/// no other references to `self`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Errors</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If another user panicked while holding this mutex, this call wraps</span>
<span class="doccomment">/// the result in an error and returns it.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use spin_sync::Mutex;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let mutex = Mutex::new(0);</span>
<span class="doccomment">/// assert_eq!(0, mutex.into_inner().unwrap());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_inner</span>(<span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">LockResult</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">is_err</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">is_poisoned</span>();
<span class="kw">let</span> <span class="ident">data</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">data</span>.<span class="ident">into_inner</span>();
<span class="kw">if</span> <span class="ident">is_err</span> {
<span class="prelude-val">Err</span>(<span class="ident">PoisonError</span>::<span class="ident">new</span>(<span class="ident">data</span>))
} <span class="kw">else</span> {
<span class="prelude-val">Ok</span>(<span class="ident">data</span>)
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> <span class="ident">Mutex</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Blocks the current thread until acquiring the lock, and returns an RAII guard object.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The actual flow will be as follows.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// 1. User calls this method.</span>
<span class="doccomment">/// 1. Blocks until this thread acquires the exclusive lock.</span>
<span class="doccomment">/// 1. Creates an RAII guard object.</span>
<span class="doccomment">/// 1. Wraps the guard in `Result` and returns it. If this mutex has been</span>
<span class="doccomment">/// poisoned, it is wrapped in an `Err`; otherwise wrapped in a `Ok`.</span>
<span class="doccomment">/// 1. User accesses to the underlying data through the returned guard.</span>
<span class="doccomment">/// (No other thread can access to the data then.)</span>
<span class="doccomment">/// 1. The guard is dropped (falls out of scope) and the lock is released.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Errors</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If another user panicked while holding this mutex, this method call wraps</span>
<span class="doccomment">/// the guard in an error and returns it.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use spin_sync::Mutex;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let mutex = Mutex::new(0);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let mut guard = mutex.lock().unwrap();</span>
<span class="doccomment">/// assert_eq!(0, *guard);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// *guard += 1;</span>
<span class="doccomment">/// assert_eq!(1, *guard);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(true, mutex.try_lock().is_err());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">lock</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">LockResult</span><span class="op"><</span><span class="ident">MutexGuard</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span> {
<span class="kw">loop</span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">do_try_lock</span>() {
<span class="ident">s</span> <span class="kw">if</span> <span class="ident">is_locked</span>(<span class="ident">s</span>) <span class="op">=</span><span class="op">></span> <span class="ident">std</span>::<span class="ident">thread</span>::<span class="ident">yield_now</span>(),
<span class="ident">s</span> <span class="kw">if</span> <span class="ident">is_poisoned</span>(<span class="ident">s</span>) <span class="op">=</span><span class="op">></span> <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">PoisonError</span>::<span class="ident">new</span>(<span class="ident">MutexGuard</span>::<span class="ident">new</span>(<span class="self">self</span>))),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="ident">MutexGuard</span>::<span class="ident">new</span>(<span class="self">self</span>)),
}
}
}
<span class="doccomment">/// Attempts to acquire this lock and returns an RAII guard object if succeeded.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Behaves like [`lock`] except for this method returns an error immediately if another</span>
<span class="doccomment">/// user is holding the lock.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This method does not block.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The actual flow will be as follows.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// 1. User calls this method.</span>
<span class="doccomment">/// 1. Tries to acquire the lock. If failed (i.e. if the lock is being held,)</span>
<span class="doccomment">/// returns an error immediately and this flow is finished here.</span>
<span class="doccomment">/// 1. Creates an RAII guard object.</span>
<span class="doccomment">/// 1. Wrapps the guard in `Result` and returns it. If this mutex has been</span>
<span class="doccomment">/// poisoned, it is wrapped in an `Err`; otherwise wrapped in an `Ok`.</span>
<span class="doccomment">/// 1. User accesses to the underlying data through the returned guard.</span>
<span class="doccomment">/// (No other thread can access to the data then.)</span>
<span class="doccomment">/// 1. The guard is dropped (falls out of scope) and the lock is released.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Errors</span>
<span class="doccomment">///</span>
<span class="doccomment">/// - If another user is holding this mutex, [`TryLockError::WouldBlock`] is returned.</span>
<span class="doccomment">/// - If this function call succeeded to acquire the lock, and if another</span>
<span class="doccomment">/// user panicked while holding this mutex, [`TryLockError::Poisoned`] is returned.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`lock`]: #method.lock</span>
<span class="doccomment">/// [`TryLockError::WouldBlock`]: type.TryLockError.html</span>
<span class="doccomment">/// [`TryLockError::Poisoned`]: type.TryLockError.html</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use spin_sync::Mutex;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let mutex = Mutex::new(0);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // try_lock() fails while another guard is.</span>
<span class="doccomment">/// // It doesn't cause a deadlock.</span>
<span class="doccomment">/// {</span>
<span class="doccomment">/// let _guard = mutex.lock().unwrap();</span>
<span class="doccomment">/// assert_eq!(true, mutex.try_lock().is_err());</span>
<span class="doccomment">/// }</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // try_lock() behaves like lock() if no other guard is.</span>
<span class="doccomment">/// {</span>
<span class="doccomment">/// let mut guard = mutex.try_lock().unwrap();</span>
<span class="doccomment">/// assert_eq!(true, mutex.try_lock().is_err());</span>
<span class="doccomment">/// *guard += 1;</span>
<span class="doccomment">/// }</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let guard = mutex.try_lock().unwrap();</span>
<span class="doccomment">/// assert_eq!(1, *guard);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">try_lock</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">TryLockResult</span><span class="op"><</span><span class="ident">MutexGuard</span><span class="op"><</span><span class="ident">T</span><span class="op">></span><span class="op">></span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">do_try_lock</span>() {
<span class="ident">s</span> <span class="kw">if</span> <span class="ident">is_locked</span>(<span class="ident">s</span>) <span class="op">=</span><span class="op">></span> <span class="prelude-val">Err</span>(<span class="ident">TryLockError</span>::<span class="ident">WouldBlock</span>),
<span class="ident">s</span> <span class="kw">if</span> <span class="ident">is_poisoned</span>(<span class="ident">s</span>) <span class="op">=</span><span class="op">></span> <span class="prelude-val">Err</span>(<span class="ident">TryLockError</span>::<span class="ident">Poisoned</span>(<span class="ident">PoisonError</span>::<span class="ident">new</span>(<span class="ident">MutexGuard</span>::<span class="ident">new</span>(
<span class="self">self</span>,
)))),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">Ok</span>(<span class="ident">MutexGuard</span>::<span class="ident">new</span>(<span class="self">self</span>)),
}
}
<span class="doccomment">/// Tries to acquire lock and returns the lock status before updated.</span>
<span class="kw">fn</span> <span class="ident">do_try_lock</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">LockStatus</span> {
<span class="comment">// Assume neither poisoned nor locked at first.</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">expected</span> <span class="op">=</span> <span class="ident">INIT</span>;
<span class="kw">loop</span> {
<span class="kw">let</span> <span class="ident">desired</span> <span class="op">=</span> <span class="ident">acquire_lock</span>(<span class="ident">expected</span>);
<span class="kw">match</span> <span class="self">self</span>
.<span class="ident">lock</span>
.<span class="ident">compare_and_swap</span>(<span class="ident">expected</span>, <span class="ident">desired</span>, <span class="ident">Ordering</span>::<span class="ident">Acquire</span>)
{
<span class="ident">s</span> <span class="kw">if</span> <span class="ident">s</span> <span class="op">=</span><span class="op">=</span> <span class="ident">expected</span> <span class="op">=</span><span class="op">></span> <span class="kw">return</span> <span class="ident">s</span>, <span class="comment">// Succeeded</span>
<span class="ident">s</span> <span class="kw">if</span> <span class="ident">is_locked</span>(<span class="ident">s</span>) <span class="op">=</span><span class="op">></span> <span class="kw">return</span> <span class="ident">s</span>, <span class="comment">// Another user is holding the lock.</span>
<span class="ident">s</span> <span class="op">=</span><span class="op">></span> <span class="ident">expected</span> <span class="op">=</span> <span class="ident">s</span>, <span class="comment">// Assumption was wrong. Try again.</span>
}
}
}
<span class="doccomment">/// Determines whether the mutex is poisoned or not.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Warnings</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function won't acquire any lock. If another thread is active,</span>
<span class="doccomment">/// the mutex can become poisoned at any time. You should not trust a `false`</span>
<span class="doccomment">/// value for program correctness without additional synchronization.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This behavior is same to `std::sync::Mutex::is_poisoned()`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use spin_sync::Mutex;</span>
<span class="doccomment">/// use std::sync::Arc;</span>
<span class="doccomment">/// use std::thread;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let mutex = Arc::new(Mutex::new(0));</span>
<span class="doccomment">/// assert_eq!(false, mutex.is_poisoned());</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // Panic and poison the mutex.</span>
<span class="doccomment">/// {</span>
<span class="doccomment">/// let mutex = mutex.clone();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let _ = thread::spawn(move || {</span>
<span class="doccomment">/// // This panic while holding the lock (`_guard` is in scope) will poison</span>
<span class="doccomment">/// // the mutex.</span>
<span class="doccomment">/// let _guard = mutex.lock().unwrap();</span>
<span class="doccomment">/// panic!("Poison here");</span>
<span class="doccomment">/// }).join();</span>
<span class="doccomment">/// }</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(true, mutex.is_poisoned());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_poisoned</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="comment">// Don't acquire any lock; otherwise, this function will cause</span>
<span class="comment">// a deadlock if the caller thread is holding the lock.</span>
<span class="kw">let</span> <span class="ident">status</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">lock</span>.<span class="ident">load</span>(<span class="ident">Ordering</span>::<span class="ident">Relaxed</span>);
<span class="kw">return</span> <span class="ident">is_poisoned</span>(<span class="ident">status</span>);
}
<span class="doccomment">/// Returns a mutable reference to the underlying data.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that this method won't acquire any lock because we know there is</span>
<span class="doccomment">/// no other references to `self`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Errors</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If another user panicked while holding this mutex, this method call</span>
<span class="doccomment">/// wraps the result in an error and returns it.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use spin_sync::Mutex;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let mut mutex = Mutex::new(0);</span>
<span class="doccomment">/// *mutex.get_mut().unwrap() = 10;</span>
<span class="doccomment">/// assert_eq!(10, *mutex.lock().unwrap());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_mut</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">LockResult</span><span class="op"><</span><span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">T</span><span class="op">></span> {
<span class="comment">// There is no other references to `self` because the argument is</span>
<span class="comment">// a mutable reference.</span>
<span class="comment">// No lock is required.</span>
<span class="kw">let</span> <span class="ident">data</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span><span class="self">self</span>.<span class="ident">data</span>.<span class="ident">get</span>() };
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">is_poisoned</span>() {
<span class="prelude-val">Err</span>(<span class="ident">PoisonError</span>::<span class="ident">new</span>(<span class="ident">data</span>))
} <span class="kw">else</span> {
<span class="prelude-val">Ok</span>(<span class="ident">data</span>)
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span> <span class="op">+</span> <span class="ident">fmt</span>::<span class="ident">Debug</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">Mutex</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</span>::<span class="ident">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</span>::<span class="prelude-ty">Result</span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">try_lock</span>() {
<span class="prelude-val">Ok</span>(<span class="ident">guard</span>) <span class="op">=</span><span class="op">></span> <span class="ident">f</span>.<span class="ident">debug_struct</span>(<span class="string">"Mutex"</span>).<span class="ident">field</span>(<span class="string">"data"</span>, <span class="op">&&</span><span class="kw-2">*</span><span class="ident">guard</span>).<span class="ident">finish</span>(),
<span class="prelude-val">Err</span>(<span class="ident">TryLockError</span>::<span class="ident">Poisoned</span>(<span class="ident">err</span>)) <span class="op">=</span><span class="op">></span> <span class="ident">f</span>
.<span class="ident">debug_struct</span>(<span class="string">"Mutex"</span>)
.<span class="ident">field</span>(<span class="string">"data"</span>, <span class="op">&&</span><span class="kw-2">*</span><span class="kw-2">*</span><span class="ident">err</span>.<span class="ident">get_ref</span>())
.<span class="ident">finish</span>(),
<span class="prelude-val">Err</span>(<span class="ident">TryLockError</span>::<span class="ident">WouldBlock</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">struct</span> <span class="ident">LockedPlaceholder</span>;
<span class="kw">impl</span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">LockedPlaceholder</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</span>::<span class="ident">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</span>::<span class="prelude-ty">Result</span> {
<span class="ident">f</span>.<span class="ident">write_str</span>(<span class="string">"<locked>"</span>)
}
}
<span class="ident">f</span>.<span class="ident">debug_struct</span>(<span class="string">"Mutex"</span>)
.<span class="ident">field</span>(<span class="string">"data"</span>, <span class="kw-2">&</span><span class="ident">LockedPlaceholder</span>)
.<span class="ident">finish</span>()
}
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">From</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Mutex</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">t</span>: <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="ident">Mutex</span>::<span class="ident">new</span>(<span class="ident">t</span>)
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span> <span class="op">+</span> <span class="ident">Default</span><span class="op">></span> <span class="ident">Default</span> <span class="kw">for</span> <span class="ident">Mutex</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="ident">Mutex</span>::<span class="ident">new</span>(<span class="ident">T</span>::<span class="ident">default</span>())
}
}
<span class="doccomment">/// An RAII implementation of a "scoped lock" of a mutex.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// When this structure is dropped (falls out of scope), the lock will be released.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The data protected by the mutex can be accessed through this guard via its</span>
<span class="doccomment">/// `Deref` and `DerefMut` implementations.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This structure is created by [`lock`] and [`try_lock`] methods on</span>
<span class="doccomment">/// [`Mutex`].</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`lock`]: struct.Mutex.html#method.lock</span>
<span class="doccomment">/// [`try_lock`]: struct.Mutex.html#method.try_lock</span>
<span class="doccomment">/// [`Mutex`]: struct.Mutex.html</span>
<span class="attribute">#[<span class="ident">must_use</span> <span class="op">=</span> <span class="string">"if unused the Mutex will immediately unlock"</span>]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">MutexGuard</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span> <span class="op">+</span> <span class="lifetime">'a</span><span class="op">></span> {
<span class="ident">mutex</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">Mutex</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>,
<span class="ident">_phantom</span>: <span class="ident">PhantomMutexGuard</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">T</span><span class="op">></span>, <span class="comment">// To implement !Send.</span>
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> <span class="ident">MutexGuard</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">mutex</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">Mutex</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="self">Self</span> {
<span class="ident">mutex</span>,
<span class="ident">_phantom</span>: <span class="ident">Default</span>::<span class="ident">default</span>(),
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">MutexGuard</span><span class="op"><</span><span class="lifetime">'_</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="ident">old_status</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">mutex</span>.<span class="ident">lock</span>.<span class="ident">load</span>(<span class="ident">Ordering</span>::<span class="ident">Relaxed</span>);
<span class="macro">debug_assert</span><span class="macro">!</span>(<span class="ident">is_locked</span>(<span class="ident">old_status</span>));
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">new_status</span> <span class="op">=</span> <span class="ident">release_lock</span>(<span class="ident">old_status</span>);
<span class="kw">if</span> <span class="ident">std</span>::<span class="ident">thread</span>::<span class="ident">panicking</span>() {
<span class="ident">new_status</span> <span class="op">=</span> <span class="ident">set_poison_flag</span>(<span class="ident">new_status</span>);
}
<span class="self">self</span>.<span class="ident">mutex</span>.<span class="ident">lock</span>.<span class="ident">store</span>(<span class="ident">new_status</span>, <span class="ident">Ordering</span>::<span class="ident">Release</span>);
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> <span class="ident">Deref</span> <span class="kw">for</span> <span class="ident">MutexGuard</span><span class="op"><</span><span class="lifetime">'_</span>, <span class="ident">T</span><span class="op">></span> {
<span class="kw">type</span> <span class="ident">Target</span> <span class="op">=</span> <span class="ident">T</span>;
<span class="kw">fn</span> <span class="ident">deref</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="self">Self</span>::<span class="ident">Target</span> {
<span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span><span class="self">self</span>.<span class="ident">mutex</span>.<span class="ident">data</span>.<span class="ident">get</span>() }
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> <span class="ident">DerefMut</span> <span class="kw">for</span> <span class="ident">MutexGuard</span><span class="op"><</span><span class="lifetime">'_</span>, <span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">deref_mut</span>(<span class="kw-2">&</span><span class="kw-2">mut</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="self">Self</span>::<span class="ident">Target</span> {
<span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span><span class="self">self</span>.<span class="ident">mutex</span>.<span class="ident">data</span>.<span class="ident">get</span>() }
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span> <span class="op">+</span> <span class="ident">fmt</span>::<span class="ident">Debug</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">MutexGuard</span><span class="op"><</span><span class="lifetime">'_</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</span>::<span class="ident">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</span>::<span class="prelude-ty">Result</span> {
<span class="ident">fmt</span>::<span class="ident">Debug</span>::<span class="ident">fmt</span>(<span class="kw-2">&</span><span class="kw-2">*</span><span class="kw-2">*</span><span class="self">self</span>, <span class="ident">f</span>)
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span> <span class="op">+</span> <span class="ident">fmt</span>::<span class="ident">Display</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Display</span> <span class="kw">for</span> <span class="ident">MutexGuard</span><span class="op"><</span><span class="lifetime">'_</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</span>::<span class="ident">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</span>::<span class="prelude-ty">Result</span> {
<span class="ident">fmt</span>::<span class="ident">Display</span>::<span class="ident">fmt</span>(<span class="kw-2">&</span><span class="kw-2">*</span><span class="kw-2">*</span><span class="self">self</span>, <span class="ident">f</span>)
}
}
<span class="comment">//</span>
<span class="comment">// Marker Traits</span>
<span class="comment">//</span>
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> <span class="ident">UnwindSafe</span> <span class="kw">for</span> <span class="ident">Mutex</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="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> <span class="ident">RefUnwindSafe</span> <span class="kw">for</span> <span class="ident">Mutex</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="question-mark">?</span><span class="ident">Sized</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">></span> <span class="ident">Send</span> <span class="kw">for</span> <span class="ident">Mutex</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="question-mark">?</span><span class="ident">Sized</span> <span class="op">+</span> <span class="ident">Send</span><span class="op">></span> <span class="ident">Sync</span> <span class="kw">for</span> <span class="ident">Mutex</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="question-mark">?</span><span class="ident">Sized</span> <span class="op">+</span> <span class="ident">Sync</span><span class="op">></span> <span class="ident">Sync</span> <span class="kw">for</span> <span class="ident">MutexGuard</span><span class="op"><</span><span class="lifetime">'_</span>, <span class="ident">T</span><span class="op">></span> {}
<span class="comment">//</span>
<span class="comment">// Constants to represent lock state</span>
<span class="comment">//</span>
<span class="kw">type</span> <span class="ident">LockStatus</span> <span class="op">=</span> <span class="ident">u8</span>;
<span class="kw">const</span> <span class="ident">INIT</span>: <span class="ident">LockStatus</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">const</span> <span class="ident">LOCK_FLAG</span>: <span class="ident">LockStatus</span> <span class="op">=</span> <span class="number">0x01</span>;
<span class="kw">const</span> <span class="ident">POISON_FLAG</span>: <span class="ident">LockStatus</span> <span class="op">=</span> <span class="number">0x02</span>;
<span class="kw">const</span> <span class="ident">NOT_USED_MASK</span>: <span class="ident">LockStatus</span> <span class="op">=</span> <span class="number">0xfc</span>;
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">must_use</span>]</span>
<span class="kw">fn</span> <span class="ident">is_locked</span>(<span class="ident">s</span>: <span class="ident">LockStatus</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="macro">debug_assert_eq</span><span class="macro">!</span>(<span class="number">0</span>, <span class="ident">s</span> <span class="op">&</span> <span class="ident">NOT_USED_MASK</span>);
(<span class="ident">s</span> <span class="op">&</span> <span class="ident">LOCK_FLAG</span>) <span class="op">!</span><span class="op">=</span> <span class="number">0</span>
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">must_use</span>]</span>
<span class="kw">fn</span> <span class="ident">acquire_lock</span>(<span class="ident">s</span>: <span class="ident">LockStatus</span>) <span class="op">-</span><span class="op">></span> <span class="ident">LockStatus</span> {
<span class="macro">debug_assert_eq</span><span class="macro">!</span>(<span class="bool-val">false</span>, <span class="ident">is_locked</span>(<span class="ident">s</span>));
<span class="ident">s</span> <span class="op">|</span> <span class="ident">LOCK_FLAG</span>
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">must_use</span>]</span>
<span class="kw">fn</span> <span class="ident">release_lock</span>(<span class="ident">s</span>: <span class="ident">LockStatus</span>) <span class="op">-</span><span class="op">></span> <span class="ident">LockStatus</span> {
<span class="macro">debug_assert_eq</span><span class="macro">!</span>(<span class="bool-val">true</span>, <span class="ident">is_locked</span>(<span class="ident">s</span>));
<span class="ident">s</span> <span class="op">&</span> <span class="op">!</span>(<span class="ident">LOCK_FLAG</span>)
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">must_use</span>]</span>
<span class="kw">fn</span> <span class="ident">is_poisoned</span>(<span class="ident">s</span>: <span class="ident">LockStatus</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="macro">debug_assert_eq</span><span class="macro">!</span>(<span class="number">0</span>, <span class="ident">s</span> <span class="op">&</span> <span class="ident">NOT_USED_MASK</span>);
(<span class="ident">s</span> <span class="op">&</span> <span class="ident">POISON_FLAG</span>) <span class="op">!</span><span class="op">=</span> <span class="number">0</span>
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">must_use</span>]</span>
<span class="kw">fn</span> <span class="ident">set_poison_flag</span>(<span class="ident">s</span>: <span class="ident">LockStatus</span>) <span class="op">-</span><span class="op">></span> <span class="ident">LockStatus</span> {
<span class="macro">debug_assert_eq</span><span class="macro">!</span>(<span class="number">0</span>, <span class="ident">s</span> <span class="op">&</span> <span class="ident">NOT_USED_MASK</span>);
<span class="ident">s</span> <span class="op">|</span> <span class="ident">POISON_FLAG</span>
}
</pre></div>
</section><section id="search" class="content hidden"></section><section class="footer"></section><script>window.rootPath = "../../";window.currentCrate = "spin_sync";</script><script src="../../main.js"></script><script src="../../source-script.js"></script><script src="../../source-files.js"></script><script defer src="../../search-index.js"></script></body></html>