| <!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/time/clock.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>clock.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> |
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| </pre><pre class="rust"><code><span class="attribute">#![cfg_attr(not(feature = <span class="string">"rt"</span>), allow(dead_code))] |
| |
| </span><span class="doccomment">//! Source of time abstraction. |
| //! |
| //! By default, `std::time::Instant::now()` is used. However, when the |
| //! `test-util` feature flag is enabled, the values returned for `now()` are |
| //! configurable. |
| |
| </span><span class="macro">cfg_not_test_util! </span>{ |
| <span class="kw">use </span><span class="kw">crate</span>::time::{Instant}; |
| |
| <span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>Clock {} |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>now() -> Instant { |
| Instant::from_std(std::time::Instant::now()) |
| } |
| |
| <span class="kw">impl </span>Clock { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new(_enable_pausing: bool, _start_paused: bool) -> Clock { |
| Clock {} |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>now(<span class="kw-2">&</span><span class="self">self</span>) -> Instant { |
| now() |
| } |
| } |
| } |
| |
| <span class="macro">cfg_test_util! </span>{ |
| <span class="kw">use </span><span class="kw">crate</span>::time::{Duration, Instant}; |
| <span class="kw">use </span><span class="kw">crate</span>::loom::sync::{Arc, Mutex}; |
| |
| <span class="macro">cfg_rt! </span>{ |
| <span class="kw">fn </span>clock() -> <span class="prelude-ty">Option</span><Clock> { |
| <span class="kw">use </span><span class="kw">crate</span>::runtime::Handle; |
| |
| <span class="kw">match </span>Handle::try_current() { |
| <span class="prelude-val">Ok</span>(handle) => <span class="prelude-val">Some</span>(handle.inner.driver().clock().clone()), |
| <span class="prelude-val">Err</span>(<span class="kw-2">ref </span>e) <span class="kw">if </span>e.is_missing_context() => <span class="prelude-val">None</span>, |
| <span class="prelude-val">Err</span>(<span class="kw">_</span>) => <span class="macro">panic!</span>(<span class="string">"{}"</span>, <span class="kw">crate</span>::util::error::THREAD_LOCAL_DESTROYED_ERROR), |
| } |
| } |
| } |
| |
| <span class="macro">cfg_not_rt! </span>{ |
| <span class="kw">fn </span>clock() -> <span class="prelude-ty">Option</span><Clock> { |
| <span class="prelude-val">None |
| </span>} |
| } |
| |
| <span class="doccomment">/// A handle to a source of time. |
| </span><span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>Clock { |
| inner: Arc<Mutex<Inner>>, |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">struct </span>Inner { |
| <span class="doccomment">/// True if the ability to pause time is enabled. |
| </span>enable_pausing: bool, |
| |
| <span class="doccomment">/// Instant to use as the clock's base instant. |
| </span>base: std::time::Instant, |
| |
| <span class="doccomment">/// Instant at which the clock was last unfrozen. |
| </span>unfrozen: <span class="prelude-ty">Option</span><std::time::Instant>, |
| |
| <span class="doccomment">/// Number of `inhibit_auto_advance` calls still in effect. |
| </span>auto_advance_inhibit_count: usize, |
| } |
| |
| <span class="doccomment">/// Pauses time. |
| /// |
| /// The current value of `Instant::now()` is saved and all subsequent calls |
| /// to `Instant::now()` will return the saved value. The saved value can be |
| /// changed by [`advance`] or by the time auto-advancing once the runtime |
| /// has no work to do. This only affects the `Instant` type in Tokio, and |
| /// the `Instant` in std continues to work as normal. |
| /// |
| /// Pausing time requires the `current_thread` Tokio runtime. This is the |
| /// default runtime used by `#[tokio::test]`. The runtime can be initialized |
| /// with time in a paused state using the `Builder::start_paused` method. |
| /// |
| /// For cases where time is immediately paused, it is better to pause |
| /// the time using the `main` or `test` macro: |
| /// ``` |
| /// #[tokio::main(flavor = "current_thread", start_paused = true)] |
| /// async fn main() { |
| /// println!("Hello world"); |
| /// } |
| /// ``` |
| /// |
| /// # Panics |
| /// |
| /// Panics if time is already frozen or if called from outside of a |
| /// `current_thread` Tokio runtime. |
| /// |
| /// # Auto-advance |
| /// |
| /// If time is paused and the runtime has no work to do, the clock is |
| /// auto-advanced to the next pending timer. This means that [`Sleep`] or |
| /// other timer-backed primitives can cause the runtime to advance the |
| /// current time when awaited. |
| /// |
| /// [`Sleep`]: crate::time::Sleep |
| /// [`advance`]: crate::time::advance |
| </span><span class="attribute">#[track_caller] |
| </span><span class="kw">pub fn </span>pause() { |
| <span class="kw">let </span>clock = clock().expect(<span class="string">"time cannot be frozen from outside the Tokio runtime"</span>); |
| clock.pause(); |
| } |
| |
| <span class="doccomment">/// Resumes time. |
| /// |
| /// Clears the saved `Instant::now()` value. Subsequent calls to |
| /// `Instant::now()` will return the value returned by the system call. |
| /// |
| /// # Panics |
| /// |
| /// Panics if time is not frozen or if called from outside of the Tokio |
| /// runtime. |
| </span><span class="attribute">#[track_caller] |
| </span><span class="kw">pub fn </span>resume() { |
| <span class="kw">let </span>clock = clock().expect(<span class="string">"time cannot be frozen from outside the Tokio runtime"</span>); |
| <span class="kw">let </span><span class="kw-2">mut </span>inner = clock.inner.lock(); |
| |
| <span class="kw">if </span>inner.unfrozen.is_some() { |
| <span class="macro">panic!</span>(<span class="string">"time is not frozen"</span>); |
| } |
| |
| inner.unfrozen = <span class="prelude-val">Some</span>(std::time::Instant::now()); |
| } |
| |
| <span class="doccomment">/// Advances time. |
| /// |
| /// Increments the saved `Instant::now()` value by `duration`. Subsequent |
| /// calls to `Instant::now()` will return the result of the increment. |
| /// |
| /// This function will make the current time jump forward by the given |
| /// duration in one jump. This means that all `sleep` calls with a deadline |
| /// before the new time will immediately complete "at the same time", and |
| /// the runtime is free to poll them in any order. Additionally, this |
| /// method will not wait for the `sleep` calls it advanced past to complete. |
| /// If you want to do that, you should instead call [`sleep`] and rely on |
| /// the runtime's auto-advance feature. |
| /// |
| /// Note that calls to `sleep` are not guaranteed to complete the first time |
| /// they are polled after a call to `advance`. For example, this can happen |
| /// if the runtime has not yet touched the timer driver after the call to |
| /// `advance`. However if they don't, the runtime will poll the task again |
| /// shortly. |
| /// |
| /// # Panics |
| /// |
| /// Panics if time is not frozen or if called from outside of the Tokio |
| /// runtime. |
| /// |
| /// # Auto-advance |
| /// |
| /// If the time is paused and there is no work to do, the runtime advances |
| /// time to the next timer. See [`pause`](pause#auto-advance) for more |
| /// details. |
| /// |
| /// [`sleep`]: fn@crate::time::sleep |
| </span><span class="kw">pub async fn </span>advance(duration: Duration) { |
| <span class="kw">let </span>clock = clock().expect(<span class="string">"time cannot be frozen from outside the Tokio runtime"</span>); |
| clock.advance(duration); |
| |
| <span class="kw">crate</span>::task::yield_now().<span class="kw">await</span>; |
| } |
| |
| <span class="doccomment">/// Returns the current instant, factoring in frozen time. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>now() -> Instant { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(clock) = clock() { |
| clock.now() |
| } <span class="kw">else </span>{ |
| Instant::from_std(std::time::Instant::now()) |
| } |
| } |
| |
| <span class="kw">impl </span>Clock { |
| <span class="doccomment">/// Returns a new `Clock` instance that uses the current execution context's |
| /// source of time. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new(enable_pausing: bool, start_paused: bool) -> Clock { |
| <span class="kw">let </span>now = std::time::Instant::now(); |
| |
| <span class="kw">let </span>clock = Clock { |
| inner: Arc::new(Mutex::new(Inner { |
| enable_pausing, |
| base: now, |
| unfrozen: <span class="prelude-val">Some</span>(now), |
| auto_advance_inhibit_count: <span class="number">0</span>, |
| })), |
| }; |
| |
| <span class="kw">if </span>start_paused { |
| clock.pause(); |
| } |
| |
| clock |
| } |
| |
| <span class="attribute">#[track_caller] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>pause(<span class="kw-2">&</span><span class="self">self</span>) { |
| <span class="kw">let </span><span class="kw-2">mut </span>inner = <span class="self">self</span>.inner.lock(); |
| |
| <span class="kw">if </span>!inner.enable_pausing { |
| drop(inner); <span class="comment">// avoid poisoning the lock |
| </span><span class="macro">panic!</span>(<span class="string">"`time::pause()` requires the `current_thread` Tokio runtime. \ |
| This is the default Runtime used by `#[tokio::test]."</span>); |
| } |
| |
| <span class="kw">let </span>elapsed = inner.unfrozen.as_ref().expect(<span class="string">"time is already frozen"</span>).elapsed(); |
| inner.base += elapsed; |
| inner.unfrozen = <span class="prelude-val">None</span>; |
| } |
| |
| <span class="doccomment">/// Temporarily stop auto-advancing the clock (see `tokio::time::pause`). |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>inhibit_auto_advance(<span class="kw-2">&</span><span class="self">self</span>) { |
| <span class="kw">let </span><span class="kw-2">mut </span>inner = <span class="self">self</span>.inner.lock(); |
| inner.auto_advance_inhibit_count += <span class="number">1</span>; |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>allow_auto_advance(<span class="kw-2">&</span><span class="self">self</span>) { |
| <span class="kw">let </span><span class="kw-2">mut </span>inner = <span class="self">self</span>.inner.lock(); |
| inner.auto_advance_inhibit_count -= <span class="number">1</span>; |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>can_auto_advance(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="kw">let </span>inner = <span class="self">self</span>.inner.lock(); |
| inner.unfrozen.is_none() && inner.auto_advance_inhibit_count == <span class="number">0 |
| </span>} |
| |
| <span class="attribute">#[track_caller] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>advance(<span class="kw-2">&</span><span class="self">self</span>, duration: Duration) { |
| <span class="kw">let </span><span class="kw-2">mut </span>inner = <span class="self">self</span>.inner.lock(); |
| |
| <span class="kw">if </span>inner.unfrozen.is_some() { |
| <span class="macro">panic!</span>(<span class="string">"time is not frozen"</span>); |
| } |
| |
| inner.base += duration; |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>now(<span class="kw-2">&</span><span class="self">self</span>) -> Instant { |
| <span class="kw">let </span>inner = <span class="self">self</span>.inner.lock(); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>ret = inner.base; |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(unfrozen) = inner.unfrozen { |
| ret += unfrozen.elapsed(); |
| } |
| |
| Instant::from_std(ret) |
| } |
| } |
| } |
| </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> |
