| <!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 `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-util-0.3.28/src/lock/bilock.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>bilock.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../futures_util/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../futures_util/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-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> |
| </pre><pre class="rust"><code><span class="doccomment">//! Futures-powered synchronization primitives. |
| |
| </span><span class="kw">use </span>alloc::boxed::Box; |
| <span class="kw">use </span>alloc::sync::Arc; |
| <span class="kw">use </span>core::cell::UnsafeCell; |
| <span class="kw">use </span>core::ops::{Deref, DerefMut}; |
| <span class="kw">use </span>core::pin::Pin; |
| <span class="kw">use </span>core::sync::atomic::AtomicPtr; |
| <span class="kw">use </span>core::sync::atomic::Ordering::SeqCst; |
| <span class="kw">use </span>core::{fmt, ptr}; |
| <span class="attribute">#[cfg(feature = <span class="string">"bilock"</span>)] |
| </span><span class="kw">use </span>futures_core::future::Future; |
| <span class="kw">use </span>futures_core::task::{Context, Poll, Waker}; |
| |
| <span class="doccomment">/// A type of futures-powered synchronization primitive which is a mutex between |
| /// two possible owners. |
| /// |
| /// This primitive is not as generic as a full-blown mutex but is sufficient for |
| /// many use cases where there are only two possible owners of a resource. The |
| /// implementation of `BiLock` can be more optimized for just the two possible |
| /// owners. |
| /// |
| /// Note that it's possible to use this lock through a poll-style interface with |
| /// the `poll_lock` method but you can also use it as a future with the `lock` |
| /// method that consumes a `BiLock` and returns a future that will resolve when |
| /// it's locked. |
| /// |
| /// A `BiLock` is typically used for "split" operations where data which serves |
| /// two purposes wants to be split into two to be worked with separately. For |
| /// example a TCP stream could be both a reader and a writer or a framing layer |
| /// could be both a stream and a sink for messages. A `BiLock` enables splitting |
| /// these two and then using each independently in a futures-powered fashion. |
| /// |
| /// This type is only available when the `bilock` feature of this |
| /// library is activated. |
| </span><span class="attribute">#[derive(Debug)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"bilock"</span>)))] |
| </span><span class="kw">pub struct </span>BiLock<T> { |
| arc: Arc<Inner<T>>, |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">struct </span>Inner<T> { |
| state: AtomicPtr<Waker>, |
| value: <span class="prelude-ty">Option</span><UnsafeCell<T>>, |
| } |
| |
| <span class="kw">unsafe impl</span><T: Send> Send <span class="kw">for </span>Inner<T> {} |
| <span class="kw">unsafe impl</span><T: Send> Sync <span class="kw">for </span>Inner<T> {} |
| |
| <span class="kw">impl</span><T> BiLock<T> { |
| <span class="doccomment">/// Creates a new `BiLock` protecting the provided data. |
| /// |
| /// Two handles to the lock are returned, and these are the only two handles |
| /// that will ever be available to the lock. These can then be sent to separate |
| /// tasks to be managed there. |
| /// |
| /// The data behind the bilock is considered to be pinned, which allows `Pin` |
| /// references to locked data. However, this means that the locked value |
| /// will only be available through `Pin<&mut T>` (not `&mut T`) unless `T` is `Unpin`. |
| /// Similarly, reuniting the lock and extracting the inner value is only |
| /// possible when `T` is `Unpin`. |
| </span><span class="kw">pub fn </span>new(t: T) -> (<span class="self">Self</span>, <span class="self">Self</span>) { |
| <span class="kw">let </span>arc = Arc::new(Inner { |
| state: AtomicPtr::new(ptr::null_mut()), |
| value: <span class="prelude-val">Some</span>(UnsafeCell::new(t)), |
| }); |
| |
| (<span class="self">Self </span>{ arc: arc.clone() }, <span class="self">Self </span>{ arc }) |
| } |
| |
| <span class="doccomment">/// Attempt to acquire this lock, returning `Pending` if it can't be |
| /// acquired. |
| /// |
| /// This function will acquire the lock in a nonblocking fashion, returning |
| /// immediately if the lock is already held. If the lock is successfully |
| /// acquired then `Poll::Ready` is returned with a value that represents |
| /// the locked value (and can be used to access the protected data). The |
| /// lock is unlocked when the returned `BiLockGuard` is dropped. |
| /// |
| /// If the lock is already held then this function will return |
| /// `Poll::Pending`. In this case the current task will also be scheduled |
| /// to receive a notification when the lock would otherwise become |
| /// available. |
| /// |
| /// # Panics |
| /// |
| /// This function will panic if called outside the context of a future's |
| /// task. |
| </span><span class="kw">pub fn </span>poll_lock(<span class="kw-2">&</span><span class="self">self</span>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<BiLockGuard<<span class="lifetime">'_</span>, T>> { |
| <span class="kw">let </span><span class="kw-2">mut </span>waker = <span class="prelude-val">None</span>; |
| <span class="kw">loop </span>{ |
| <span class="kw">let </span>n = <span class="self">self</span>.arc.state.swap(invalid_ptr(<span class="number">1</span>), SeqCst); |
| <span class="kw">match </span>n <span class="kw">as </span>usize { |
| <span class="comment">// Woohoo, we grabbed the lock! |
| </span><span class="number">0 </span>=> <span class="kw">return </span>Poll::Ready(BiLockGuard { bilock: <span class="self">self </span>}), |
| |
| <span class="comment">// Oops, someone else has locked the lock |
| </span><span class="number">1 </span>=> {} |
| |
| <span class="comment">// A task was previously blocked on this lock, likely our task, |
| // so we need to update that task. |
| </span><span class="kw">_ </span>=> <span class="kw">unsafe </span>{ |
| <span class="kw">let </span><span class="kw-2">mut </span>prev = Box::from_raw(n); |
| <span class="kw-2">*</span>prev = cx.waker().clone(); |
| waker = <span class="prelude-val">Some</span>(prev); |
| }, |
| } |
| |
| <span class="comment">// type ascription for safety's sake! |
| </span><span class="kw">let </span>me: Box<Waker> = waker.take().unwrap_or_else(|| Box::new(cx.waker().clone())); |
| <span class="kw">let </span>me = Box::into_raw(me); |
| |
| <span class="kw">match </span><span class="self">self</span>.arc.state.compare_exchange(invalid_ptr(<span class="number">1</span>), me, SeqCst, SeqCst) { |
| <span class="comment">// The lock is still locked, but we've now parked ourselves, so |
| // just report that we're scheduled to receive a notification. |
| </span><span class="prelude-val">Ok</span>(<span class="kw">_</span>) => <span class="kw">return </span>Poll::Pending, |
| |
| <span class="comment">// Oops, looks like the lock was unlocked after our swap above |
| // and before the compare_exchange. Deallocate what we just |
| // allocated and go through the loop again. |
| </span><span class="prelude-val">Err</span>(n) <span class="kw">if </span>n.is_null() => <span class="kw">unsafe </span>{ |
| waker = <span class="prelude-val">Some</span>(Box::from_raw(me)); |
| }, |
| |
| <span class="comment">// The top of this loop set the previous state to 1, so if we |
| // failed the CAS above then it's because the previous value was |
| // *not* zero or one. This indicates that a task was blocked, |
| // but we're trying to acquire the lock and there's only one |
| // other reference of the lock, so it should be impossible for |
| // that task to ever block itself. |
| </span><span class="prelude-val">Err</span>(n) => <span class="macro">panic!</span>(<span class="string">"invalid state: {}"</span>, n <span class="kw">as </span>usize), |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Perform a "blocking lock" of this lock, consuming this lock handle and |
| /// returning a future to the acquired lock. |
| /// |
| /// This function consumes the `BiLock<T>` and returns a sentinel future, |
| /// `BiLockAcquire<T>`. The returned future will resolve to |
| /// `BiLockAcquired<T>` which represents a locked lock similarly to |
| /// `BiLockGuard<T>`. |
| /// |
| /// Note that the returned future will never resolve to an error. |
| </span><span class="attribute">#[cfg(feature = <span class="string">"bilock"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"bilock"</span>)))] |
| </span><span class="kw">pub fn </span>lock(<span class="kw-2">&</span><span class="self">self</span>) -> BiLockAcquire<<span class="lifetime">'_</span>, T> { |
| BiLockAcquire { bilock: <span class="self">self </span>} |
| } |
| |
| <span class="doccomment">/// Attempts to put the two "halves" of a `BiLock<T>` back together and |
| /// recover the original value. Succeeds only if the two `BiLock<T>`s |
| /// originated from the same call to `BiLock::new`. |
| </span><span class="kw">pub fn </span>reunite(<span class="self">self</span>, other: <span class="self">Self</span>) -> <span class="prelude-ty">Result</span><T, ReuniteError<T>> |
| <span class="kw">where |
| </span>T: Unpin, |
| { |
| <span class="kw">if </span>Arc::ptr_eq(<span class="kw-2">&</span><span class="self">self</span>.arc, <span class="kw-2">&</span>other.arc) { |
| drop(other); |
| <span class="kw">let </span>inner = Arc::try_unwrap(<span class="self">self</span>.arc) |
| .ok() |
| .expect(<span class="string">"futures: try_unwrap failed in BiLock<T>::reunite"</span>); |
| <span class="prelude-val">Ok</span>(<span class="kw">unsafe </span>{ inner.into_value() }) |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">Err</span>(ReuniteError(<span class="self">self</span>, other)) |
| } |
| } |
| |
| <span class="kw">fn </span>unlock(<span class="kw-2">&</span><span class="self">self</span>) { |
| <span class="kw">let </span>n = <span class="self">self</span>.arc.state.swap(ptr::null_mut(), SeqCst); |
| <span class="kw">match </span>n <span class="kw">as </span>usize { |
| <span class="comment">// we've locked the lock, shouldn't be possible for us to see an |
| // unlocked lock. |
| </span><span class="number">0 </span>=> <span class="macro">panic!</span>(<span class="string">"invalid unlocked state"</span>), |
| |
| <span class="comment">// Ok, no one else tried to get the lock, we're done. |
| </span><span class="number">1 </span>=> {} |
| |
| <span class="comment">// Another task has parked themselves on this lock, let's wake them |
| // up as its now their turn. |
| </span><span class="kw">_ </span>=> <span class="kw">unsafe </span>{ |
| Box::from_raw(n).wake(); |
| }, |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><T: Unpin> Inner<T> { |
| <span class="kw">unsafe fn </span>into_value(<span class="kw-2">mut </span><span class="self">self</span>) -> T { |
| <span class="self">self</span>.value.take().unwrap().into_inner() |
| } |
| } |
| |
| <span class="kw">impl</span><T> Drop <span class="kw">for </span>Inner<T> { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="macro">assert!</span>(<span class="self">self</span>.state.load(SeqCst).is_null()); |
| } |
| } |
| |
| <span class="doccomment">/// Error indicating two `BiLock<T>`s were not two halves of a whole, and |
| /// thus could not be `reunite`d. |
| </span><span class="attribute">#[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"bilock"</span>)))] |
| </span><span class="kw">pub struct </span>ReuniteError<T>(<span class="kw">pub </span>BiLock<T>, <span class="kw">pub </span>BiLock<T>); |
| |
| <span class="kw">impl</span><T> fmt::Debug <span class="kw">for </span>ReuniteError<T> { |
| <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| f.debug_tuple(<span class="string">"ReuniteError"</span>).field(<span class="kw-2">&</span><span class="string">"..."</span>).finish() |
| } |
| } |
| |
| <span class="kw">impl</span><T> fmt::Display <span class="kw">for </span>ReuniteError<T> { |
| <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| <span class="macro">write!</span>(f, <span class="string">"tried to reunite two BiLocks that don't form a pair"</span>) |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"std"</span>)] |
| </span><span class="kw">impl</span><T: core::any::Any> std::error::Error <span class="kw">for </span>ReuniteError<T> {} |
| |
| <span class="doccomment">/// Returned RAII guard from the `poll_lock` method. |
| /// |
| /// This structure acts as a sentinel to the data in the `BiLock<T>` itself, |
| /// implementing `Deref` and `DerefMut` to `T`. When dropped, the lock will be |
| /// unlocked. |
| </span><span class="attribute">#[derive(Debug)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"bilock"</span>)))] |
| </span><span class="kw">pub struct </span>BiLockGuard<<span class="lifetime">'a</span>, T> { |
| bilock: <span class="kw-2">&</span><span class="lifetime">'a </span>BiLock<T>, |
| } |
| |
| <span class="comment">// We allow parallel access to T via Deref, so Sync bound is also needed here. |
| </span><span class="kw">unsafe impl</span><T: Send + Sync> Sync <span class="kw">for </span>BiLockGuard<<span class="lifetime">'_</span>, T> {} |
| |
| <span class="kw">impl</span><T> Deref <span class="kw">for </span>BiLockGuard<<span class="lifetime">'_</span>, T> { |
| <span class="kw">type </span>Target = T; |
| <span class="kw">fn </span>deref(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>T { |
| <span class="kw">unsafe </span>{ <span class="kw-2">&*</span><span class="self">self</span>.bilock.arc.value.as_ref().unwrap().get() } |
| } |
| } |
| |
| <span class="kw">impl</span><T: Unpin> DerefMut <span class="kw">for </span>BiLockGuard<<span class="lifetime">'_</span>, T> { |
| <span class="kw">fn </span>deref_mut(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&mut </span>T { |
| <span class="kw">unsafe </span>{ <span class="kw-2">&mut *</span><span class="self">self</span>.bilock.arc.value.as_ref().unwrap().get() } |
| } |
| } |
| |
| <span class="kw">impl</span><T> BiLockGuard<<span class="lifetime">'_</span>, T> { |
| <span class="doccomment">/// Get a mutable pinned reference to the locked value. |
| </span><span class="kw">pub fn </span>as_pin_mut(<span class="kw-2">&mut </span><span class="self">self</span>) -> Pin<<span class="kw-2">&mut </span>T> { |
| <span class="comment">// Safety: we never allow moving a !Unpin value out of a bilock, nor |
| // allow mutable access to it |
| </span><span class="kw">unsafe </span>{ Pin::new_unchecked(<span class="kw-2">&mut *</span><span class="self">self</span>.bilock.arc.value.as_ref().unwrap().get()) } |
| } |
| } |
| |
| <span class="kw">impl</span><T> Drop <span class="kw">for </span>BiLockGuard<<span class="lifetime">'_</span>, T> { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="self">self</span>.bilock.unlock(); |
| } |
| } |
| |
| <span class="doccomment">/// Future returned by `BiLock::lock` which will resolve when the lock is |
| /// acquired. |
| </span><span class="attribute">#[cfg(feature = <span class="string">"bilock"</span>)] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"bilock"</span>)))] |
| #[must_use = <span class="string">"futures do nothing unless you `.await` or poll them"</span>] |
| #[derive(Debug)] |
| </span><span class="kw">pub struct </span>BiLockAcquire<<span class="lifetime">'a</span>, T> { |
| bilock: <span class="kw-2">&</span><span class="lifetime">'a </span>BiLock<T>, |
| } |
| |
| <span class="comment">// Pinning is never projected to fields |
| </span><span class="attribute">#[cfg(feature = <span class="string">"bilock"</span>)] |
| </span><span class="kw">impl</span><T> Unpin <span class="kw">for </span>BiLockAcquire<<span class="lifetime">'_</span>, T> {} |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"bilock"</span>)] |
| </span><span class="kw">impl</span><<span class="lifetime">'a</span>, T> Future <span class="kw">for </span>BiLockAcquire<<span class="lifetime">'a</span>, T> { |
| <span class="kw">type </span>Output = BiLockGuard<<span class="lifetime">'a</span>, T>; |
| |
| <span class="kw">fn </span>poll(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="self">Self</span>::Output> { |
| <span class="self">self</span>.bilock.poll_lock(cx) |
| } |
| } |
| |
| <span class="comment">// Based on core::ptr::invalid_mut. Equivalent to `addr as *mut T`, but is strict-provenance compatible. |
| </span><span class="attribute">#[allow(clippy::useless_transmute)] |
| #[inline] |
| </span><span class="kw">fn </span>invalid_ptr<T>(addr: usize) -> <span class="kw-2">*mut </span>T { |
| <span class="comment">// SAFETY: every valid integer is also a valid pointer (as long as you don't dereference that |
| // pointer). |
| </span><span class="kw">unsafe </span>{ core::mem::transmute(addr) } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="futures_util" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
