<!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-channel-0.5.1/src/waker.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>waker.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">
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</pre><pre class="rust">
<span class="doccomment">//! Waking mechanism for threads blocked on channel operations.</span>
<span class="kw">use</span> <span class="ident">std::sync::atomic</span>::{<span class="ident">AtomicBool</span>, <span class="ident">Ordering</span>};
<span class="kw">use</span> <span class="ident">std::thread</span>::{<span class="self">self</span>, <span class="ident">ThreadId</span>};
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::context::Context</span>;
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::select</span>::{<span class="ident">Operation</span>, <span class="ident">Selected</span>};
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::utils::Spinlock</span>;
<span class="doccomment">/// Represents a thread blocked on a specific channel operation.</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct</span> <span class="ident">Entry</span> {
<span class="doccomment">/// The operation.</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="ident">oper</span>: <span class="ident">Operation</span>,
<span class="doccomment">/// Optional packet.</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="ident">packet</span>: <span class="ident">usize</span>,
<span class="doccomment">/// Context associated with the thread owning this operation.</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="ident">cx</span>: <span class="ident">Context</span>,
}
<span class="doccomment">/// A queue of threads blocked on channel operations.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This data structure is used by threads to register blocking operations and get woken up once</span>
<span class="doccomment">/// an operation becomes ready.</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct</span> <span class="ident">Waker</span> {
<span class="doccomment">/// A list of select operations.</span>
<span class="ident">selectors</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">Entry</span><span class="op">></span>,
<span class="doccomment">/// A list of operations waiting to be ready.</span>
<span class="ident">observers</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">Entry</span><span class="op">></span>,
}
<span class="kw">impl</span> <span class="ident">Waker</span> {
<span class="doccomment">/// Creates a new `Waker`.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">new</span>() <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="ident">Waker</span> {
<span class="ident">selectors</span>: <span class="ident">Vec::new</span>(),
<span class="ident">observers</span>: <span class="ident">Vec::new</span>(),
}
}
<span class="doccomment">/// Registers a select operation.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">register</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">oper</span>: <span class="ident">Operation</span>, <span class="ident">cx</span>: <span class="kw-2">&</span><span class="ident">Context</span>) {
<span class="self">self</span>.<span class="ident">register_with_packet</span>(<span class="ident">oper</span>, <span class="number">0</span>, <span class="ident">cx</span>);
}
<span class="doccomment">/// Registers a select operation and a packet.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">register_with_packet</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">oper</span>: <span class="ident">Operation</span>, <span class="ident">packet</span>: <span class="ident">usize</span>, <span class="ident">cx</span>: <span class="kw-2">&</span><span class="ident">Context</span>) {
<span class="self">self</span>.<span class="ident">selectors</span>.<span class="ident">push</span>(<span class="ident">Entry</span> {
<span class="ident">oper</span>,
<span class="ident">packet</span>,
<span class="ident">cx</span>: <span class="ident">cx</span>.<span class="ident">clone</span>(),
});
}
<span class="doccomment">/// Unregisters a select operation.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">unregister</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">oper</span>: <span class="ident">Operation</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">Entry</span><span class="op">></span> {
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>((<span class="ident">i</span>, <span class="kw">_</span>)) <span class="op">=</span> <span class="self">self</span>
.<span class="ident">selectors</span>
.<span class="ident">iter</span>()
.<span class="ident">enumerate</span>()
.<span class="ident">find</span>(<span class="op">|</span><span class="kw-2">&</span>(<span class="kw">_</span>, <span class="ident">entry</span>)<span class="op">|</span> <span class="ident">entry</span>.<span class="ident">oper</span> <span class="op">=</span><span class="op">=</span> <span class="ident">oper</span>)
{
<span class="kw">let</span> <span class="ident">entry</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">selectors</span>.<span class="ident">remove</span>(<span class="ident">i</span>);
<span class="prelude-val">Some</span>(<span class="ident">entry</span>)
} <span class="kw">else</span> {
<span class="prelude-val">None</span>
}
}
<span class="doccomment">/// Attempts to find another thread's entry, select the operation, and wake it up.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">try_select</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="prelude-ty">Option</span><span class="op"><</span><span class="ident">Entry</span><span class="op">></span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">entry</span> <span class="op">=</span> <span class="prelude-val">None</span>;
<span class="kw">if</span> <span class="op">!</span><span class="self">self</span>.<span class="ident">selectors</span>.<span class="ident">is_empty</span>() {
<span class="kw">let</span> <span class="ident">thread_id</span> <span class="op">=</span> <span class="ident">current_thread_id</span>();
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="self">self</span>.<span class="ident">selectors</span>.<span class="ident">len</span>() {
<span class="comment">// Does the entry belong to a different thread?</span>
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">selectors</span>[<span class="ident">i</span>].<span class="ident">cx</span>.<span class="ident">thread_id</span>() <span class="op">!</span><span class="op">=</span> <span class="ident">thread_id</span> {
<span class="comment">// Try selecting this operation.</span>
<span class="kw">let</span> <span class="ident">sel</span> <span class="op">=</span> <span class="ident">Selected::Operation</span>(<span class="self">self</span>.<span class="ident">selectors</span>[<span class="ident">i</span>].<span class="ident">oper</span>);
<span class="kw">let</span> <span class="ident">res</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">selectors</span>[<span class="ident">i</span>].<span class="ident">cx</span>.<span class="ident">try_select</span>(<span class="ident">sel</span>);
<span class="kw">if</span> <span class="ident">res</span>.<span class="ident">is_ok</span>() {
<span class="comment">// Provide the packet.</span>
<span class="self">self</span>.<span class="ident">selectors</span>[<span class="ident">i</span>].<span class="ident">cx</span>.<span class="ident">store_packet</span>(<span class="self">self</span>.<span class="ident">selectors</span>[<span class="ident">i</span>].<span class="ident">packet</span>);
<span class="comment">// Wake the thread up.</span>
<span class="self">self</span>.<span class="ident">selectors</span>[<span class="ident">i</span>].<span class="ident">cx</span>.<span class="ident">unpark</span>();
<span class="comment">// Remove the entry from the queue to keep it clean and improve</span>
<span class="comment">// performance.</span>
<span class="ident">entry</span> <span class="op">=</span> <span class="prelude-val">Some</span>(<span class="self">self</span>.<span class="ident">selectors</span>.<span class="ident">remove</span>(<span class="ident">i</span>));
<span class="kw">break</span>;
}
}
}
}
<span class="ident">entry</span>
}
<span class="doccomment">/// Returns `true` if there is an entry which can be selected by the current thread.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">can_select</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">if</span> <span class="self">self</span>.<span class="ident">selectors</span>.<span class="ident">is_empty</span>() {
<span class="bool-val">false</span>
} <span class="kw">else</span> {
<span class="kw">let</span> <span class="ident">thread_id</span> <span class="op">=</span> <span class="ident">current_thread_id</span>();
<span class="self">self</span>.<span class="ident">selectors</span>.<span class="ident">iter</span>().<span class="ident">any</span>(<span class="op">|</span><span class="ident">entry</span><span class="op">|</span> {
<span class="ident">entry</span>.<span class="ident">cx</span>.<span class="ident">thread_id</span>() <span class="op">!</span><span class="op">=</span> <span class="ident">thread_id</span> <span class="op">&&</span> <span class="ident">entry</span>.<span class="ident">cx</span>.<span class="ident">selected</span>() <span class="op">=</span><span class="op">=</span> <span class="ident">Selected::Waiting</span>
})
}
}
<span class="doccomment">/// Registers an operation waiting to be ready.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">watch</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">oper</span>: <span class="ident">Operation</span>, <span class="ident">cx</span>: <span class="kw-2">&</span><span class="ident">Context</span>) {
<span class="self">self</span>.<span class="ident">observers</span>.<span class="ident">push</span>(<span class="ident">Entry</span> {
<span class="ident">oper</span>,
<span class="ident">packet</span>: <span class="number">0</span>,
<span class="ident">cx</span>: <span class="ident">cx</span>.<span class="ident">clone</span>(),
});
}
<span class="doccomment">/// Unregisters an operation waiting to be ready.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">unwatch</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">oper</span>: <span class="ident">Operation</span>) {
<span class="self">self</span>.<span class="ident">observers</span>.<span class="ident">retain</span>(<span class="op">|</span><span class="ident">e</span><span class="op">|</span> <span class="ident">e</span>.<span class="ident">oper</span> <span class="op">!</span><span class="op">=</span> <span class="ident">oper</span>);
}
<span class="doccomment">/// Notifies all operations waiting to be ready.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">notify</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="kw">for</span> <span class="ident">entry</span> <span class="kw">in</span> <span class="self">self</span>.<span class="ident">observers</span>.<span class="ident">drain</span>(..) {
<span class="kw">if</span> <span class="ident">entry</span>.<span class="ident">cx</span>.<span class="ident">try_select</span>(<span class="ident">Selected::Operation</span>(<span class="ident">entry</span>.<span class="ident">oper</span>)).<span class="ident">is_ok</span>() {
<span class="ident">entry</span>.<span class="ident">cx</span>.<span class="ident">unpark</span>();
}
}
}
<span class="doccomment">/// Notifies all registered operations that the channel is disconnected.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">disconnect</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="kw">for</span> <span class="ident">entry</span> <span class="kw">in</span> <span class="self">self</span>.<span class="ident">selectors</span>.<span class="ident">iter</span>() {
<span class="kw">if</span> <span class="ident">entry</span>.<span class="ident">cx</span>.<span class="ident">try_select</span>(<span class="ident">Selected::Disconnected</span>).<span class="ident">is_ok</span>() {
<span class="comment">// Wake the thread up.</span>
<span class="comment">//</span>
<span class="comment">// Here we don't remove the entry from the queue. Registered threads must</span>
<span class="comment">// unregister from the waker by themselves. They might also want to recover the</span>
<span class="comment">// packet value and destroy it, if necessary.</span>
<span class="ident">entry</span>.<span class="ident">cx</span>.<span class="ident">unpark</span>();
}
}
<span class="self">self</span>.<span class="ident">notify</span>();
}
}
<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">Waker</span> {
<span class="attribute">#[<span class="ident">inline</span>]</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="macro">debug_assert_eq!</span>(<span class="self">self</span>.<span class="ident">selectors</span>.<span class="ident">len</span>(), <span class="number">0</span>);
<span class="macro">debug_assert_eq!</span>(<span class="self">self</span>.<span class="ident">observers</span>.<span class="ident">len</span>(), <span class="number">0</span>);
}
}
<span class="doccomment">/// A waker that can be shared among threads without locking.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is a simple wrapper around `Waker` that internally uses a mutex for synchronization.</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct</span> <span class="ident">SyncWaker</span> {
<span class="doccomment">/// The inner `Waker`.</span>
<span class="ident">inner</span>: <span class="ident">Spinlock</span><span class="op"><</span><span class="ident">Waker</span><span class="op">></span>,
<span class="doccomment">/// `true` if the waker is empty.</span>
<span class="ident">is_empty</span>: <span class="ident">AtomicBool</span>,
}
<span class="kw">impl</span> <span class="ident">SyncWaker</span> {
<span class="doccomment">/// Creates a new `SyncWaker`.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">new</span>() <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="ident">SyncWaker</span> {
<span class="ident">inner</span>: <span class="ident">Spinlock::new</span>(<span class="ident">Waker::new</span>()),
<span class="ident">is_empty</span>: <span class="ident">AtomicBool::new</span>(<span class="bool-val">true</span>),
}
}
<span class="doccomment">/// Registers the current thread with an operation.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">register</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">oper</span>: <span class="ident">Operation</span>, <span class="ident">cx</span>: <span class="kw-2">&</span><span class="ident">Context</span>) {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">inner</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">lock</span>();
<span class="ident">inner</span>.<span class="ident">register</span>(<span class="ident">oper</span>, <span class="ident">cx</span>);
<span class="self">self</span>.<span class="ident">is_empty</span>.<span class="ident">store</span>(
<span class="ident">inner</span>.<span class="ident">selectors</span>.<span class="ident">is_empty</span>() <span class="op">&&</span> <span class="ident">inner</span>.<span class="ident">observers</span>.<span class="ident">is_empty</span>(),
<span class="ident">Ordering::SeqCst</span>,
);
}
<span class="doccomment">/// Unregisters an operation previously registered by the current thread.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">unregister</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">oper</span>: <span class="ident">Operation</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">Entry</span><span class="op">></span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">inner</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">lock</span>();
<span class="kw">let</span> <span class="ident">entry</span> <span class="op">=</span> <span class="ident">inner</span>.<span class="ident">unregister</span>(<span class="ident">oper</span>);
<span class="self">self</span>.<span class="ident">is_empty</span>.<span class="ident">store</span>(
<span class="ident">inner</span>.<span class="ident">selectors</span>.<span class="ident">is_empty</span>() <span class="op">&&</span> <span class="ident">inner</span>.<span class="ident">observers</span>.<span class="ident">is_empty</span>(),
<span class="ident">Ordering::SeqCst</span>,
);
<span class="ident">entry</span>
}
<span class="doccomment">/// Attempts to find one thread (not the current one), select its operation, and wake it up.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">notify</span>(<span class="kw-2">&</span><span class="self">self</span>) {
<span class="kw">if</span> <span class="op">!</span><span class="self">self</span>.<span class="ident">is_empty</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">inner</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">lock</span>();
<span class="kw">if</span> <span class="op">!</span><span class="self">self</span>.<span class="ident">is_empty</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>) {
<span class="ident">inner</span>.<span class="ident">try_select</span>();
<span class="ident">inner</span>.<span class="ident">notify</span>();
<span class="self">self</span>.<span class="ident">is_empty</span>.<span class="ident">store</span>(
<span class="ident">inner</span>.<span class="ident">selectors</span>.<span class="ident">is_empty</span>() <span class="op">&&</span> <span class="ident">inner</span>.<span class="ident">observers</span>.<span class="ident">is_empty</span>(),
<span class="ident">Ordering::SeqCst</span>,
);
}
}
}
<span class="doccomment">/// Registers an operation waiting to be ready.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">watch</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">oper</span>: <span class="ident">Operation</span>, <span class="ident">cx</span>: <span class="kw-2">&</span><span class="ident">Context</span>) {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">inner</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">lock</span>();
<span class="ident">inner</span>.<span class="ident">watch</span>(<span class="ident">oper</span>, <span class="ident">cx</span>);
<span class="self">self</span>.<span class="ident">is_empty</span>.<span class="ident">store</span>(
<span class="ident">inner</span>.<span class="ident">selectors</span>.<span class="ident">is_empty</span>() <span class="op">&&</span> <span class="ident">inner</span>.<span class="ident">observers</span>.<span class="ident">is_empty</span>(),
<span class="ident">Ordering::SeqCst</span>,
);
}
<span class="doccomment">/// Unregisters an operation waiting to be ready.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">unwatch</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">oper</span>: <span class="ident">Operation</span>) {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">inner</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">lock</span>();
<span class="ident">inner</span>.<span class="ident">unwatch</span>(<span class="ident">oper</span>);
<span class="self">self</span>.<span class="ident">is_empty</span>.<span class="ident">store</span>(
<span class="ident">inner</span>.<span class="ident">selectors</span>.<span class="ident">is_empty</span>() <span class="op">&&</span> <span class="ident">inner</span>.<span class="ident">observers</span>.<span class="ident">is_empty</span>(),
<span class="ident">Ordering::SeqCst</span>,
);
}
<span class="doccomment">/// Notifies all threads that the channel is disconnected.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">disconnect</span>(<span class="kw-2">&</span><span class="self">self</span>) {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">inner</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">lock</span>();
<span class="ident">inner</span>.<span class="ident">disconnect</span>();
<span class="self">self</span>.<span class="ident">is_empty</span>.<span class="ident">store</span>(
<span class="ident">inner</span>.<span class="ident">selectors</span>.<span class="ident">is_empty</span>() <span class="op">&&</span> <span class="ident">inner</span>.<span class="ident">observers</span>.<span class="ident">is_empty</span>(),
<span class="ident">Ordering::SeqCst</span>,
);
}
}
<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">SyncWaker</span> {
<span class="attribute">#[<span class="ident">inline</span>]</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="macro">debug_assert_eq!</span>(<span class="self">self</span>.<span class="ident">is_empty</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>), <span class="bool-val">true</span>);
}
}
<span class="doccomment">/// Returns the id of the current thread.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">current_thread_id</span>() <span class="op">-</span><span class="op">></span> <span class="ident">ThreadId</span> {
<span class="macro">thread_local!</span> {
<span class="doccomment">/// Cached thread-local id.</span>
<span class="kw">static</span> <span class="ident">THREAD_ID</span>: <span class="ident">ThreadId</span> <span class="op">=</span> <span class="ident">thread::current</span>().<span class="ident">id</span>();
}
<span class="ident">THREAD_ID</span>
.<span class="ident">try_with</span>(<span class="op">|</span><span class="ident">id</span><span class="op">|</span> <span class="kw-2">*</span><span class="ident">id</span>)
.<span class="ident">unwrap_or_else</span>(<span class="op">|</span><span class="kw">_</span><span class="op">|</span> <span class="ident">thread::current</span>().<span class="ident">id</span>())
}
</pre></div>
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