Google Git
Sign in
apache / incubator-teaclave-website / refs/heads/asf-site / . / api-docs / crates-enclave / src / tokio / runtime / time / mod.rs.html
blob: b3546fe2a6e0c4f180aae22146342da72b94d339 [file] [log] [blame]
<!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/git/checkouts/tokio-377c595163f99a10/dfe252d/tokio/src/runtime/time/mod.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>mod.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="../../../../tokio/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="../../../../tokio/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>
<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>
</pre><pre class="rust"><code><span class="comment">// Currently, rust warns when an unsafe fn contains an unsafe {} block. However,
// in the future, this will change to the reverse. For now, suppress this
// warning and generally stick with being explicit about unsafety.
</span><span class="attribute">#![allow(unused_unsafe)]
#![cfg_attr(not(feature = <span class="string">&quot;rt&quot;</span>), allow(dead_code))]
</span><span class="doccomment">//! Time driver.
</span><span class="kw">mod </span>entry;
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>entry::TimerEntry;
<span class="kw">use </span>entry::{EntryList, TimerHandle, TimerShared};
<span class="kw">mod </span>handle;
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span><span class="self">self</span>::handle::Handle;
<span class="kw">mod </span>source;
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">use </span>source::TimeSource;
<span class="kw">mod </span>wheel;
<span class="kw">use </span><span class="kw">crate</span>::loom::sync::atomic::{AtomicBool, Ordering};
<span class="kw">use </span><span class="kw">crate</span>::loom::sync::Mutex;
<span class="kw">use </span><span class="kw">crate</span>::runtime::driver::{<span class="self">self</span>, IoHandle, IoStack};
<span class="kw">use </span><span class="kw">crate</span>::time::error::Error;
<span class="kw">use </span><span class="kw">crate</span>::time::{Clock, Duration};
<span class="kw">use </span>std::fmt;
<span class="kw">use </span>std::{num::NonZeroU64, ptr::NonNull, task::Waker};
<span class="doccomment">/// Time implementation that drives [`Sleep`][sleep], [`Interval`][interval], and [`Timeout`][timeout].
///
/// A `Driver` instance tracks the state necessary for managing time and
/// notifying the [`Sleep`][sleep] instances once their deadlines are reached.
///
/// It is expected that a single instance manages many individual [`Sleep`][sleep]
/// instances. The `Driver` implementation is thread-safe and, as such, is able
/// to handle callers from across threads.
///
/// After creating the `Driver` instance, the caller must repeatedly call `park`
/// or `park_timeout`. The time driver will perform no work unless `park` or
/// `park_timeout` is called repeatedly.
///
/// The driver has a resolution of one millisecond. Any unit of time that falls
/// between milliseconds are rounded up to the next millisecond.
///
/// When an instance is dropped, any outstanding [`Sleep`][sleep] instance that has not
/// elapsed will be notified with an error. At this point, calling `poll` on the
/// [`Sleep`][sleep] instance will result in panic.
///
/// # Implementation
///
/// The time driver is based on the [paper by Varghese and Lauck][paper].
///
/// A hashed timing wheel is a vector of slots, where each slot handles a time
/// slice. As time progresses, the timer walks over the slot for the current
/// instant, and processes each entry for that slot. When the timer reaches the
/// end of the wheel, it starts again at the beginning.
///
/// The implementation maintains six wheels arranged in a set of levels. As the
/// levels go up, the slots of the associated wheel represent larger intervals
/// of time. At each level, the wheel has 64 slots. Each slot covers a range of
/// time equal to the wheel at the lower level. At level zero, each slot
/// represents one millisecond of time.
///
/// The wheels are:
///
/// * Level 0: 64 x 1 millisecond slots.
/// * Level 1: 64 x 64 millisecond slots.
/// * Level 2: 64 x ~4 second slots.
/// * Level 3: 64 x ~4 minute slots.
/// * Level 4: 64 x ~4 hour slots.
/// * Level 5: 64 x ~12 day slots.
///
/// When the timer processes entries at level zero, it will notify all the
/// `Sleep` instances as their deadlines have been reached. For all higher
/// levels, all entries will be redistributed across the wheel at the next level
/// down. Eventually, as time progresses, entries with [`Sleep`][sleep] instances will
/// either be canceled (dropped) or their associated entries will reach level
/// zero and be notified.
///
/// [paper]: http://www.cs.columbia.edu/~nahum/w6998/papers/ton97-timing-wheels.pdf
/// [sleep]: crate::time::Sleep
/// [timeout]: crate::time::Timeout
/// [interval]: crate::time::Interval
</span><span class="attribute">#[derive(Debug)]
</span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>Driver {
<span class="doccomment">/// Parker to delegate to.
</span>park: IoStack,
}
<span class="doccomment">/// Timer state shared between `Driver`, `Handle`, and `Registration`.
</span><span class="kw">struct </span>Inner {
<span class="comment">// The state is split like this so `Handle` can access `is_shutdown` without locking the mutex
</span><span class="kw">pub</span>(<span class="kw">super</span>) state: Mutex&lt;InnerState&gt;,
<span class="doccomment">/// True if the driver is being shutdown.
</span><span class="kw">pub</span>(<span class="kw">super</span>) is_shutdown: AtomicBool,
<span class="comment">// When `true`, a call to `park_timeout` should immediately return and time
// should not advance. One reason for this to be `true` is if the task
// passed to `Runtime::block_on` called `task::yield_now()`.
//
// While it may look racy, it only has any effect when the clock is paused
// and pausing the clock is restricted to a single-threaded runtime.
</span><span class="attribute">#[cfg(feature = <span class="string">&quot;test-util&quot;</span>)]
</span>did_wake: AtomicBool,
}
<span class="doccomment">/// Time state shared which must be protected by a `Mutex`
</span><span class="kw">struct </span>InnerState {
<span class="doccomment">/// The last published timer `elapsed` value.
</span>elapsed: u64,
<span class="doccomment">/// The earliest time at which we promise to wake up without unparking.
</span>next_wake: <span class="prelude-ty">Option</span>&lt;NonZeroU64&gt;,
<span class="doccomment">/// Timer wheel.
</span>wheel: wheel::Wheel,
}
<span class="comment">// ===== impl Driver =====
</span><span class="kw">impl </span>Driver {
<span class="doccomment">/// Creates a new `Driver` instance that uses `park` to block the current
/// thread and `time_source` to get the current time and convert to ticks.
///
/// Specifying the source of time is useful when testing.
</span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new(park: IoStack, clock: Clock) -&gt; (Driver, Handle) {
<span class="kw">let </span>time_source = TimeSource::new(clock);
<span class="kw">let </span>handle = Handle {
time_source,
inner: Inner {
state: Mutex::new(InnerState {
elapsed: <span class="number">0</span>,
next_wake: <span class="prelude-val">None</span>,
wheel: wheel::Wheel::new(),
}),
is_shutdown: AtomicBool::new(<span class="bool-val">false</span>),
<span class="attribute">#[cfg(feature = <span class="string">&quot;test-util&quot;</span>)]
</span>did_wake: AtomicBool::new(<span class="bool-val">false</span>),
},
};
<span class="kw">let </span>driver = Driver { park };
(driver, handle)
}
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>park(<span class="kw-2">&amp;mut </span><span class="self">self</span>, handle: <span class="kw-2">&amp;</span>driver::Handle) {
<span class="self">self</span>.park_internal(handle, <span class="prelude-val">None</span>)
}
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>park_timeout(<span class="kw-2">&amp;mut </span><span class="self">self</span>, handle: <span class="kw-2">&amp;</span>driver::Handle, duration: Duration) {
<span class="self">self</span>.park_internal(handle, <span class="prelude-val">Some</span>(duration))
}
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>shutdown(<span class="kw-2">&amp;mut </span><span class="self">self</span>, rt_handle: <span class="kw-2">&amp;</span>driver::Handle) {
<span class="kw">let </span>handle = rt_handle.time();
<span class="kw">if </span>handle.is_shutdown() {
<span class="kw">return</span>;
}
handle.inner.is_shutdown.store(<span class="bool-val">true</span>, Ordering::SeqCst);
<span class="comment">// Advance time forward to the end of time.
</span>handle.process_at_time(u64::MAX);
<span class="self">self</span>.park.shutdown(rt_handle);
}
<span class="kw">fn </span>park_internal(<span class="kw-2">&amp;mut </span><span class="self">self</span>, rt_handle: <span class="kw-2">&amp;</span>driver::Handle, limit: <span class="prelude-ty">Option</span>&lt;Duration&gt;) {
<span class="kw">let </span>handle = rt_handle.time();
<span class="kw">let </span><span class="kw-2">mut </span>lock = handle.inner.state.lock();
<span class="macro">assert!</span>(!handle.is_shutdown());
<span class="kw">let </span>next_wake = lock.wheel.next_expiration_time();
lock.next_wake =
next_wake.map(|t| NonZeroU64::new(t).unwrap_or_else(|| NonZeroU64::new(<span class="number">1</span>).unwrap()));
drop(lock);
<span class="kw">match </span>next_wake {
<span class="prelude-val">Some</span>(when) =&gt; {
<span class="kw">let </span>now = handle.time_source.now();
<span class="comment">// Note that we effectively round up to 1ms here - this avoids
// very short-duration microsecond-resolution sleeps that the OS
// might treat as zero-length.
</span><span class="kw">let </span><span class="kw-2">mut </span>duration = handle
.time_source
.tick_to_duration(when.saturating_sub(now));
<span class="kw">if </span>duration &gt; Duration::from_millis(<span class="number">0</span>) {
<span class="kw">if let </span><span class="prelude-val">Some</span>(limit) = limit {
duration = std::cmp::min(limit, duration);
}
<span class="self">self</span>.park_thread_timeout(rt_handle, duration);
} <span class="kw">else </span>{
<span class="self">self</span>.park.park_timeout(rt_handle, Duration::from_secs(<span class="number">0</span>));
}
}
<span class="prelude-val">None </span>=&gt; {
<span class="kw">if let </span><span class="prelude-val">Some</span>(duration) = limit {
<span class="self">self</span>.park_thread_timeout(rt_handle, duration);
} <span class="kw">else </span>{
<span class="self">self</span>.park.park(rt_handle);
}
}
}
<span class="comment">// Process pending timers after waking up
</span>handle.process();
}
<span class="macro">cfg_test_util! </span>{
<span class="kw">fn </span>park_thread_timeout(<span class="kw-2">&amp;mut </span><span class="self">self</span>, rt_handle: <span class="kw-2">&amp;</span>driver::Handle, duration: Duration) {
<span class="kw">let </span>handle = rt_handle.time();
<span class="kw">let </span>clock = <span class="kw-2">&amp;</span>handle.time_source.clock;
<span class="kw">if </span>clock.can_auto_advance() {
<span class="self">self</span>.park.park_timeout(rt_handle, Duration::from_secs(<span class="number">0</span>));
<span class="comment">// If the time driver was woken, then the park completed
// before the &quot;duration&quot; elapsed (usually caused by a
// yield in `Runtime::block_on`). In this case, we don&#39;t
// advance the clock.
</span><span class="kw">if </span>!handle.did_wake() {
<span class="comment">// Simulate advancing time
</span>clock.advance(duration);
}
} <span class="kw">else </span>{
<span class="self">self</span>.park.park_timeout(rt_handle, duration);
}
}
}
<span class="macro">cfg_not_test_util! </span>{
<span class="kw">fn </span>park_thread_timeout(<span class="kw-2">&amp;mut </span><span class="self">self</span>, rt_handle: <span class="kw-2">&amp;</span>driver::Handle, duration: Duration) {
<span class="self">self</span>.park.park_timeout(rt_handle, duration);
}
}
}
<span class="kw">impl </span>Handle {
<span class="doccomment">/// Runs timer related logic, and returns the next wakeup time
</span><span class="kw">pub</span>(<span class="self">self</span>) <span class="kw">fn </span>process(<span class="kw-2">&amp;</span><span class="self">self</span>) {
<span class="kw">let </span>now = <span class="self">self</span>.time_source().now();
<span class="self">self</span>.process_at_time(now)
}
<span class="kw">pub</span>(<span class="self">self</span>) <span class="kw">fn </span>process_at_time(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="kw-2">mut </span>now: u64) {
<span class="kw">let </span><span class="kw-2">mut </span>waker_list: [<span class="prelude-ty">Option</span>&lt;Waker&gt;; <span class="number">32</span>] = Default::default();
<span class="kw">let </span><span class="kw-2">mut </span>waker_idx = <span class="number">0</span>;
<span class="kw">let </span><span class="kw-2">mut </span>lock = <span class="self">self</span>.inner.lock();
<span class="kw">if </span>now &lt; lock.elapsed {
<span class="comment">// Time went backwards! This normally shouldn&#39;t happen as the Rust language
// guarantees that an Instant is monotonic, but can happen when running
// Linux in a VM on a Windows host due to std incorrectly trusting the
// hardware clock to be monotonic.
//
// See &lt;https://github.com/tokio-rs/tokio/issues/3619&gt; for more information.
</span>now = lock.elapsed;
}
<span class="kw">while let </span><span class="prelude-val">Some</span>(entry) = lock.wheel.poll(now) {
<span class="macro">debug_assert!</span>(<span class="kw">unsafe </span>{ entry.is_pending() });
<span class="comment">// SAFETY: We hold the driver lock, and just removed the entry from any linked lists.
</span><span class="kw">if let </span><span class="prelude-val">Some</span>(waker) = <span class="kw">unsafe </span>{ entry.fire(<span class="prelude-val">Ok</span>(())) } {
waker_list[waker_idx] = <span class="prelude-val">Some</span>(waker);
waker_idx += <span class="number">1</span>;
<span class="kw">if </span>waker_idx == waker_list.len() {
<span class="comment">// Wake a batch of wakers. To avoid deadlock, we must do this with the lock temporarily dropped.
</span>drop(lock);
<span class="kw">for </span>waker <span class="kw">in </span>waker_list.iter_mut() {
waker.take().unwrap().wake();
}
waker_idx = <span class="number">0</span>;
lock = <span class="self">self</span>.inner.lock();
}
}
}
<span class="comment">// Update the elapsed cache
</span>lock.elapsed = lock.wheel.elapsed();
lock.next_wake = lock
.wheel
.poll_at()
.map(|t| NonZeroU64::new(t).unwrap_or_else(|| NonZeroU64::new(<span class="number">1</span>).unwrap()));
drop(lock);
<span class="kw">for </span>waker <span class="kw">in </span>waker_list[<span class="number">0</span>..waker_idx].iter_mut() {
waker.take().unwrap().wake();
}
}
<span class="doccomment">/// Removes a registered timer from the driver.
///
/// The timer will be moved to the cancelled state. Wakers will _not_ be
/// invoked. If the timer is already completed, this function is a no-op.
///
/// This function always acquires the driver lock, even if the entry does
/// not appear to be registered.
///
/// SAFETY: The timer must not be registered with some other driver, and
/// `add_entry` must not be called concurrently.
</span><span class="kw">pub</span>(<span class="self">self</span>) <span class="kw">unsafe fn </span>clear_entry(<span class="kw-2">&amp;</span><span class="self">self</span>, entry: NonNull&lt;TimerShared&gt;) {
<span class="kw">unsafe </span>{
<span class="kw">let </span><span class="kw-2">mut </span>lock = <span class="self">self</span>.inner.lock();
<span class="kw">if </span>entry.as_ref().might_be_registered() {
lock.wheel.remove(entry);
}
entry.as_ref().handle().fire(<span class="prelude-val">Ok</span>(()));
}
}
<span class="doccomment">/// Removes and re-adds an entry to the driver.
///
/// SAFETY: The timer must be either unregistered, or registered with this
/// driver. No other threads are allowed to concurrently manipulate the
/// timer at all (the current thread should hold an exclusive reference to
/// the `TimerEntry`)
</span><span class="kw">pub</span>(<span class="self">self</span>) <span class="kw">unsafe fn </span>reregister(
<span class="kw-2">&amp;</span><span class="self">self</span>,
unpark: <span class="kw-2">&amp;</span>IoHandle,
new_tick: u64,
entry: NonNull&lt;TimerShared&gt;,
) {
<span class="kw">let </span>waker = <span class="kw">unsafe </span>{
<span class="kw">let </span><span class="kw-2">mut </span>lock = <span class="self">self</span>.inner.lock();
<span class="comment">// We may have raced with a firing/deregistration, so check before
// deregistering.
</span><span class="kw">if unsafe </span>{ entry.as_ref().might_be_registered() } {
lock.wheel.remove(entry);
}
<span class="comment">// Now that we have exclusive control of this entry, mint a handle to reinsert it.
</span><span class="kw">let </span>entry = entry.as_ref().handle();
<span class="kw">if </span><span class="self">self</span>.is_shutdown() {
<span class="kw">unsafe </span>{ entry.fire(<span class="prelude-val">Err</span>(<span class="kw">crate</span>::time::error::Error::shutdown())) }
} <span class="kw">else </span>{
entry.set_expiration(new_tick);
<span class="comment">// Note: We don&#39;t have to worry about racing with some other resetting
// thread, because add_entry and reregister require exclusive control of
// the timer entry.
</span><span class="kw">match unsafe </span>{ lock.wheel.insert(entry) } {
<span class="prelude-val">Ok</span>(when) =&gt; {
<span class="kw">if </span>lock
.next_wake
.map(|next_wake| when &lt; next_wake.get())
.unwrap_or(<span class="bool-val">true</span>)
{
unpark.unpark();
}
<span class="prelude-val">None
</span>}
<span class="prelude-val">Err</span>((entry, <span class="kw">crate</span>::time::error::InsertError::Elapsed)) =&gt; <span class="kw">unsafe </span>{
entry.fire(<span class="prelude-val">Ok</span>(()))
},
}
}
<span class="comment">// Must release lock before invoking waker to avoid the risk of deadlock.
</span>};
<span class="comment">// The timer was fired synchronously as a result of the reregistration.
// Wake the waker; this is needed because we might reset _after_ a poll,
// and otherwise the task won&#39;t be awoken to poll again.
</span><span class="kw">if let </span><span class="prelude-val">Some</span>(waker) = waker {
waker.wake();
}
}
<span class="macro">cfg_test_util! </span>{
<span class="kw">fn </span>did_wake(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; bool {
<span class="self">self</span>.inner.did_wake.swap(<span class="bool-val">false</span>, Ordering::SeqCst)
}
}
}
<span class="comment">// ===== impl Inner =====
</span><span class="kw">impl </span>Inner {
<span class="doccomment">/// Locks the driver&#39;s inner structure
</span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>lock(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="kw">crate</span>::loom::sync::MutexGuard&lt;<span class="lifetime">&#39;_</span>, InnerState&gt; {
<span class="self">self</span>.state.lock()
}
<span class="comment">// Check whether the driver has been shutdown
</span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>is_shutdown(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; bool {
<span class="self">self</span>.is_shutdown.load(Ordering::SeqCst)
}
}
<span class="kw">impl </span>fmt::Debug <span class="kw">for </span>Inner {
<span class="kw">fn </span>fmt(<span class="kw-2">&amp;</span><span class="self">self</span>, fmt: <span class="kw-2">&amp;mut </span>fmt::Formatter&lt;<span class="lifetime">&#39;_</span>&gt;) -&gt; fmt::Result {
fmt.debug_struct(<span class="string">&quot;Inner&quot;</span>).finish()
}
}
<span class="attribute">#[cfg(test)]
</span><span class="kw">mod </span>tests;
</code></pre></div>
</section></div></main><div id="rustdoc-vars" data-root-path="../../../../" data-current-crate="tokio" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html>