| <!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/task/task_local.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>task_local.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="kw">use </span>std::cell::RefCell; |
| <span class="kw">use </span>std::error::Error; |
| <span class="kw">use </span>std::future::Future; |
| <span class="kw">use </span>std::marker::PhantomPinned; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| <span class="kw">use </span>std::{fmt, mem, thread}; |
| |
| <span class="doccomment">/// Declares a new task-local key of type [`tokio::task::LocalKey`]. |
| /// |
| /// # Syntax |
| /// |
| /// The macro wraps any number of static declarations and makes them local to the current task. |
| /// Publicity and attributes for each static is preserved. For example: |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # use tokio::task_local; |
| /// task_local! { |
| /// pub static ONE: u32; |
| /// |
| /// #[allow(unused)] |
| /// static TWO: f32; |
| /// } |
| /// # fn main() {} |
| /// ``` |
| /// |
| /// See [LocalKey documentation][`tokio::task::LocalKey`] for more |
| /// information. |
| /// |
| /// [`tokio::task::LocalKey`]: struct@crate::task::LocalKey |
| </span><span class="attribute">#[macro_export] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"rt"</span>)))] |
| </span><span class="macro">macro_rules! </span>task_local { |
| <span class="comment">// empty (base case for the recursion) |
| </span>() => {}; |
| |
| ($(<span class="attribute">#[<span class="macro-nonterminal">$attr</span>:meta]</span>)* <span class="macro-nonterminal">$vis</span>:vis <span class="kw">static </span><span class="macro-nonterminal">$name</span>:ident: <span class="macro-nonterminal">$t</span>:ty; $(<span class="macro-nonterminal">$rest</span>:tt)<span class="kw-2">*</span>) => { |
| <span class="macro-nonterminal">$</span><span class="macro">crate::__task_local_inner!</span>($(<span class="attribute">#[<span class="macro-nonterminal">$attr</span>]</span>)* <span class="macro-nonterminal">$vis $name</span>, <span class="macro-nonterminal">$t</span>); |
| <span class="macro-nonterminal">$</span><span class="macro">crate::task_local!</span>($(<span class="macro-nonterminal">$rest</span>)<span class="kw-2">*</span>); |
| }; |
| |
| ($(<span class="attribute">#[<span class="macro-nonterminal">$attr</span>:meta]</span>)* <span class="macro-nonterminal">$vis</span>:vis <span class="kw">static </span><span class="macro-nonterminal">$name</span>:ident: <span class="macro-nonterminal">$t</span>:ty) => { |
| <span class="macro-nonterminal">$</span><span class="macro">crate::__task_local_inner!</span>($(<span class="attribute">#[<span class="macro-nonterminal">$attr</span>]</span>)* <span class="macro-nonterminal">$vis $name</span>, <span class="macro-nonterminal">$t</span>); |
| } |
| } |
| |
| <span class="attribute">#[doc(hidden)] |
| #[cfg(not(tokio_no_const_thread_local))] |
| #[macro_export] |
| </span><span class="macro">macro_rules! </span>__task_local_inner { |
| ($(<span class="attribute">#[<span class="macro-nonterminal">$attr</span>:meta]</span>)* <span class="macro-nonterminal">$vis</span>:vis <span class="macro-nonterminal">$name</span>:ident, <span class="macro-nonterminal">$t</span>:ty) => { |
| $(<span class="attribute">#[<span class="macro-nonterminal">$attr</span>]</span>)* |
| <span class="macro-nonterminal">$vis </span><span class="kw">static </span><span class="macro-nonterminal">$name</span>: <span class="macro-nonterminal">$crate::task::LocalKey</span><<span class="macro-nonterminal">$t</span>> = { |
| <span class="macro">std::thread_local! </span>{ |
| <span class="kw">static </span>__KEY: std::cell::RefCell<<span class="prelude-ty">Option</span><<span class="macro-nonterminal">$t</span>>> = <span class="kw">const </span>{ std::cell::RefCell::new(<span class="prelude-val">None</span>) }; |
| } |
| |
| <span class="macro-nonterminal">$crate::task::LocalKey </span>{ inner: __KEY } |
| }; |
| }; |
| } |
| |
| <span class="attribute">#[doc(hidden)] |
| #[cfg(tokio_no_const_thread_local)] |
| #[macro_export] |
| </span><span class="macro">macro_rules! </span>__task_local_inner { |
| ($(<span class="attribute">#[<span class="macro-nonterminal">$attr</span>:meta]</span>)* <span class="macro-nonterminal">$vis</span>:vis <span class="macro-nonterminal">$name</span>:ident, <span class="macro-nonterminal">$t</span>:ty) => { |
| $(<span class="attribute">#[<span class="macro-nonterminal">$attr</span>]</span>)* |
| <span class="macro-nonterminal">$vis </span><span class="kw">static </span><span class="macro-nonterminal">$name</span>: <span class="macro-nonterminal">$crate::task::LocalKey</span><<span class="macro-nonterminal">$t</span>> = { |
| <span class="macro">std::thread_local! </span>{ |
| <span class="kw">static </span>__KEY: std::cell::RefCell<<span class="prelude-ty">Option</span><<span class="macro-nonterminal">$t</span>>> = std::cell::RefCell::new(<span class="prelude-val">None</span>); |
| } |
| |
| <span class="macro-nonterminal">$crate::task::LocalKey </span>{ inner: __KEY } |
| }; |
| }; |
| } |
| |
| <span class="doccomment">/// A key for task-local data. |
| /// |
| /// This type is generated by the [`task_local!`] macro. |
| /// |
| /// Unlike [`std::thread::LocalKey`], `tokio::task::LocalKey` will |
| /// _not_ lazily initialize the value on first access. Instead, the |
| /// value is first initialized when the future containing |
| /// the task-local is first polled by a futures executor, like Tokio. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # async fn dox() { |
| /// tokio::task_local! { |
| /// static NUMBER: u32; |
| /// } |
| /// |
| /// NUMBER.scope(1, async move { |
| /// assert_eq!(NUMBER.get(), 1); |
| /// }).await; |
| /// |
| /// NUMBER.scope(2, async move { |
| /// assert_eq!(NUMBER.get(), 2); |
| /// |
| /// NUMBER.scope(3, async move { |
| /// assert_eq!(NUMBER.get(), 3); |
| /// }).await; |
| /// }).await; |
| /// # } |
| /// ``` |
| /// |
| /// [`std::thread::LocalKey`]: struct@std::thread::LocalKey |
| /// [`task_local!`]: ../macro.task_local.html |
| </span><span class="attribute">#[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"rt"</span>)))] |
| </span><span class="kw">pub struct </span>LocalKey<T: <span class="lifetime">'static</span>> { |
| <span class="attribute">#[doc(hidden)] |
| </span><span class="kw">pub </span>inner: thread::LocalKey<RefCell<<span class="prelude-ty">Option</span><T>>>, |
| } |
| |
| <span class="kw">impl</span><T: <span class="lifetime">'static</span>> LocalKey<T> { |
| <span class="doccomment">/// Sets a value `T` as the task-local value for the future `F`. |
| /// |
| /// On completion of `scope`, the task-local will be dropped. |
| /// |
| /// ### Panics |
| /// |
| /// If you poll the returned future inside a call to [`with`] or |
| /// [`try_with`] on the same `LocalKey`, then the call to `poll` will panic. |
| /// |
| /// ### Examples |
| /// |
| /// ``` |
| /// # async fn dox() { |
| /// tokio::task_local! { |
| /// static NUMBER: u32; |
| /// } |
| /// |
| /// NUMBER.scope(1, async move { |
| /// println!("task local value: {}", NUMBER.get()); |
| /// }).await; |
| /// # } |
| /// ``` |
| /// |
| /// [`with`]: fn@Self::with |
| /// [`try_with`]: fn@Self::try_with |
| </span><span class="kw">pub fn </span>scope<F>(<span class="kw-2">&</span><span class="lifetime">'static </span><span class="self">self</span>, value: T, f: F) -> TaskLocalFuture<T, F> |
| <span class="kw">where |
| </span>F: Future, |
| { |
| TaskLocalFuture { |
| local: <span class="self">self</span>, |
| slot: <span class="prelude-val">Some</span>(value), |
| future: <span class="prelude-val">Some</span>(f), |
| _pinned: PhantomPinned, |
| } |
| } |
| |
| <span class="doccomment">/// Sets a value `T` as the task-local value for the closure `F`. |
| /// |
| /// On completion of `sync_scope`, the task-local will be dropped. |
| /// |
| /// ### Panics |
| /// |
| /// This method panics if called inside a call to [`with`] or [`try_with`] |
| /// on the same `LocalKey`. |
| /// |
| /// ### Examples |
| /// |
| /// ``` |
| /// # async fn dox() { |
| /// tokio::task_local! { |
| /// static NUMBER: u32; |
| /// } |
| /// |
| /// NUMBER.sync_scope(1, || { |
| /// println!("task local value: {}", NUMBER.get()); |
| /// }); |
| /// # } |
| /// ``` |
| /// |
| /// [`with`]: fn@Self::with |
| /// [`try_with`]: fn@Self::try_with |
| </span><span class="attribute">#[track_caller] |
| </span><span class="kw">pub fn </span>sync_scope<F, R>(<span class="kw-2">&</span><span class="lifetime">'static </span><span class="self">self</span>, value: T, f: F) -> R |
| <span class="kw">where |
| </span>F: FnOnce() -> R, |
| { |
| <span class="kw">let </span><span class="kw-2">mut </span>value = <span class="prelude-val">Some</span>(value); |
| <span class="kw">match </span><span class="self">self</span>.scope_inner(<span class="kw-2">&mut </span>value, f) { |
| <span class="prelude-val">Ok</span>(res) => res, |
| <span class="prelude-val">Err</span>(err) => err.panic(), |
| } |
| } |
| |
| <span class="kw">fn </span>scope_inner<F, R>(<span class="kw-2">&</span><span class="lifetime">'static </span><span class="self">self</span>, slot: <span class="kw-2">&mut </span><span class="prelude-ty">Option</span><T>, f: F) -> <span class="prelude-ty">Result</span><R, ScopeInnerErr> |
| <span class="kw">where |
| </span>F: FnOnce() -> R, |
| { |
| <span class="kw">struct </span>Guard<<span class="lifetime">'a</span>, T: <span class="lifetime">'static</span>> { |
| local: <span class="kw-2">&</span><span class="lifetime">'static </span>LocalKey<T>, |
| slot: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span><span class="prelude-ty">Option</span><T>, |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, T: <span class="lifetime">'static</span>> Drop <span class="kw">for </span>Guard<<span class="lifetime">'a</span>, T> { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="comment">// This should not panic. |
| // |
| // We know that the RefCell was not borrowed before the call to |
| // `scope_inner`, so the only way for this to panic is if the |
| // closure has created but not destroyed a RefCell guard. |
| // However, we never give user-code access to the guards, so |
| // there's no way for user-code to forget to destroy a guard. |
| // |
| // The call to `with` also should not panic, since the |
| // thread-local wasn't destroyed when we first called |
| // `scope_inner`, and it shouldn't have gotten destroyed since |
| // then. |
| </span><span class="self">self</span>.local.inner.with(|inner| { |
| <span class="kw">let </span><span class="kw-2">mut </span>ref_mut = inner.borrow_mut(); |
| mem::swap(<span class="self">self</span>.slot, <span class="kw-2">&mut *</span>ref_mut); |
| }); |
| } |
| } |
| |
| <span class="self">self</span>.inner.try_with(|inner| { |
| inner |
| .try_borrow_mut() |
| .map(|<span class="kw-2">mut </span>ref_mut| mem::swap(slot, <span class="kw-2">&mut *</span>ref_mut)) |
| })<span class="question-mark">??</span>; |
| |
| <span class="kw">let </span>guard = Guard { local: <span class="self">self</span>, slot }; |
| |
| <span class="kw">let </span>res = f(); |
| |
| drop(guard); |
| |
| <span class="prelude-val">Ok</span>(res) |
| } |
| |
| <span class="doccomment">/// Accesses the current task-local and runs the provided closure. |
| /// |
| /// # Panics |
| /// |
| /// This function will panic if the task local doesn't have a value set. |
| </span><span class="attribute">#[track_caller] |
| </span><span class="kw">pub fn </span>with<F, R>(<span class="kw-2">&</span><span class="lifetime">'static </span><span class="self">self</span>, f: F) -> R |
| <span class="kw">where |
| </span>F: FnOnce(<span class="kw-2">&</span>T) -> R, |
| { |
| <span class="kw">match </span><span class="self">self</span>.try_with(f) { |
| <span class="prelude-val">Ok</span>(res) => res, |
| <span class="prelude-val">Err</span>(<span class="kw">_</span>) => <span class="macro">panic!</span>(<span class="string">"cannot access a task-local storage value without setting it first"</span>), |
| } |
| } |
| |
| <span class="doccomment">/// Accesses the current task-local and runs the provided closure. |
| /// |
| /// If the task-local with the associated key is not present, this |
| /// method will return an `AccessError`. For a panicking variant, |
| /// see `with`. |
| </span><span class="kw">pub fn </span>try_with<F, R>(<span class="kw-2">&</span><span class="lifetime">'static </span><span class="self">self</span>, f: F) -> <span class="prelude-ty">Result</span><R, AccessError> |
| <span class="kw">where |
| </span>F: FnOnce(<span class="kw-2">&</span>T) -> R, |
| { |
| <span class="comment">// If called after the thread-local storing the task-local is destroyed, |
| // then we are outside of a closure where the task-local is set. |
| // |
| // Therefore, it is correct to return an AccessError if `try_with` |
| // returns an error. |
| </span><span class="kw">let </span>try_with_res = <span class="self">self</span>.inner.try_with(|v| { |
| <span class="comment">// This call to `borrow` cannot panic because no user-defined code |
| // runs while a `borrow_mut` call is active. |
| </span>v.borrow().as_ref().map(f) |
| }); |
| |
| <span class="kw">match </span>try_with_res { |
| <span class="prelude-val">Ok</span>(<span class="prelude-val">Some</span>(res)) => <span class="prelude-val">Ok</span>(res), |
| <span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>) | <span class="prelude-val">Err</span>(<span class="kw">_</span>) => <span class="prelude-val">Err</span>(AccessError { _private: () }), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><T: Copy + <span class="lifetime">'static</span>> LocalKey<T> { |
| <span class="doccomment">/// Returns a copy of the task-local value |
| /// if the task-local value implements `Copy`. |
| /// |
| /// # Panics |
| /// |
| /// This function will panic if the task local doesn't have a value set. |
| </span><span class="attribute">#[track_caller] |
| </span><span class="kw">pub fn </span>get(<span class="kw-2">&</span><span class="lifetime">'static </span><span class="self">self</span>) -> T { |
| <span class="self">self</span>.with(|v| <span class="kw-2">*</span>v) |
| } |
| } |
| |
| <span class="kw">impl</span><T: <span class="lifetime">'static</span>> fmt::Debug <span class="kw">for </span>LocalKey<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.pad(<span class="string">"LocalKey { .. }"</span>) |
| } |
| } |
| |
| <span class="doccomment">/// A future that sets a value `T` of a task local for the future `F` during |
| /// its execution. |
| /// |
| /// The value of the task-local must be `'static` and will be dropped on the |
| /// completion of the future. |
| /// |
| /// Created by the function [`LocalKey::scope`](self::LocalKey::scope). |
| /// |
| /// ### Examples |
| /// |
| /// ``` |
| /// # async fn dox() { |
| /// tokio::task_local! { |
| /// static NUMBER: u32; |
| /// } |
| /// |
| /// NUMBER.scope(1, async move { |
| /// println!("task local value: {}", NUMBER.get()); |
| /// }).await; |
| /// # } |
| /// ``` |
| </span><span class="comment">// Doesn't use pin_project due to custom Drop. |
| </span><span class="kw">pub struct </span>TaskLocalFuture<T, F> |
| <span class="kw">where |
| </span>T: <span class="lifetime">'static</span>, |
| { |
| local: <span class="kw-2">&</span><span class="lifetime">'static </span>LocalKey<T>, |
| slot: <span class="prelude-ty">Option</span><T>, |
| future: <span class="prelude-ty">Option</span><F>, |
| _pinned: PhantomPinned, |
| } |
| |
| <span class="kw">impl</span><T: <span class="lifetime">'static</span>, F: Future> Future <span class="kw">for </span>TaskLocalFuture<T, F> { |
| <span class="kw">type </span>Output = F::Output; |
| |
| <span class="attribute">#[track_caller] |
| </span><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="comment">// safety: The TaskLocalFuture struct is `!Unpin` so there is no way to |
| // move `self.future` from now on. |
| </span><span class="kw">let </span>this = <span class="kw">unsafe </span>{ Pin::into_inner_unchecked(<span class="self">self</span>) }; |
| <span class="kw">let </span><span class="kw-2">mut </span>future_opt = <span class="kw">unsafe </span>{ Pin::new_unchecked(<span class="kw-2">&mut </span>this.future) }; |
| |
| <span class="kw">let </span>res = |
| this.local |
| .scope_inner(<span class="kw-2">&mut </span>this.slot, || <span class="kw">match </span>future_opt.as_mut().as_pin_mut() { |
| <span class="prelude-val">Some</span>(fut) => { |
| <span class="kw">let </span>res = fut.poll(cx); |
| <span class="kw">if </span>res.is_ready() { |
| future_opt.set(<span class="prelude-val">None</span>); |
| } |
| <span class="prelude-val">Some</span>(res) |
| } |
| <span class="prelude-val">None </span>=> <span class="prelude-val">None</span>, |
| }); |
| |
| <span class="kw">match </span>res { |
| <span class="prelude-val">Ok</span>(<span class="prelude-val">Some</span>(res)) => res, |
| <span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>) => <span class="macro">panic!</span>(<span class="string">"`TaskLocalFuture` polled after completion"</span>), |
| <span class="prelude-val">Err</span>(err) => err.panic(), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><T: <span class="lifetime">'static</span>, F> Drop <span class="kw">for </span>TaskLocalFuture<T, F> { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="kw">if </span>mem::needs_drop::<F>() && <span class="self">self</span>.future.is_some() { |
| <span class="comment">// Drop the future while the task-local is set, if possible. Otherwise |
| // the future is dropped normally when the `Option<F>` field drops. |
| </span><span class="kw">let </span>future = <span class="kw-2">&mut </span><span class="self">self</span>.future; |
| <span class="kw">let _ </span>= <span class="self">self</span>.local.scope_inner(<span class="kw-2">&mut </span><span class="self">self</span>.slot, || { |
| <span class="kw-2">*</span>future = <span class="prelude-val">None</span>; |
| }); |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><T: <span class="lifetime">'static</span>, F> fmt::Debug <span class="kw">for </span>TaskLocalFuture<T, F> |
| <span class="kw">where |
| </span>T: fmt::Debug, |
| { |
| <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="doccomment">/// Format the Option without Some. |
| </span><span class="kw">struct </span>TransparentOption<<span class="lifetime">'a</span>, T> { |
| value: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="prelude-ty">Option</span><T>, |
| } |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, T: fmt::Debug> fmt::Debug <span class="kw">for </span>TransparentOption<<span class="lifetime">'a</span>, 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="kw">match </span><span class="self">self</span>.value.as_ref() { |
| <span class="prelude-val">Some</span>(value) => value.fmt(f), |
| <span class="comment">// Hitting the None branch should not be possible. |
| </span><span class="prelude-val">None </span>=> f.pad(<span class="string">"<missing>"</span>), |
| } |
| } |
| } |
| |
| f.debug_struct(<span class="string">"TaskLocalFuture"</span>) |
| .field(<span class="string">"value"</span>, <span class="kw-2">&</span>TransparentOption { value: <span class="kw-2">&</span><span class="self">self</span>.slot }) |
| .finish() |
| } |
| } |
| |
| <span class="doccomment">/// An error returned by [`LocalKey::try_with`](method@LocalKey::try_with). |
| </span><span class="attribute">#[derive(Clone, Copy, Eq, PartialEq)] |
| </span><span class="kw">pub struct </span>AccessError { |
| _private: (), |
| } |
| |
| <span class="kw">impl </span>fmt::Debug <span class="kw">for </span>AccessError { |
| <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_struct(<span class="string">"AccessError"</span>).finish() |
| } |
| } |
| |
| <span class="kw">impl </span>fmt::Display <span class="kw">for </span>AccessError { |
| <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 { |
| fmt::Display::fmt(<span class="string">"task-local value not set"</span>, f) |
| } |
| } |
| |
| <span class="kw">impl </span>Error <span class="kw">for </span>AccessError {} |
| |
| <span class="kw">enum </span>ScopeInnerErr { |
| BorrowError, |
| AccessError, |
| } |
| |
| <span class="kw">impl </span>ScopeInnerErr { |
| <span class="attribute">#[track_caller] |
| </span><span class="kw">fn </span>panic(<span class="kw-2">&</span><span class="self">self</span>) -> ! { |
| <span class="kw">match </span><span class="self">self </span>{ |
| <span class="self">Self</span>::BorrowError => <span class="macro">panic!</span>(<span class="string">"cannot enter a task-local scope while the task-local storage is borrowed"</span>), |
| <span class="self">Self</span>::AccessError => <span class="macro">panic!</span>(<span class="string">"cannot enter a task-local scope during or after destruction of the underlying thread-local"</span>), |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>From<std::cell::BorrowMutError> <span class="kw">for </span>ScopeInnerErr { |
| <span class="kw">fn </span>from(<span class="kw">_</span>: std::cell::BorrowMutError) -> <span class="self">Self </span>{ |
| <span class="self">Self</span>::BorrowError |
| } |
| } |
| |
| <span class="kw">impl </span>From<std::thread::AccessError> <span class="kw">for </span>ScopeInnerErr { |
| <span class="kw">fn </span>from(<span class="kw">_</span>: std::thread::AccessError) -> <span class="self">Self </span>{ |
| <span class="self">Self</span>::AccessError |
| } |
| } |
| </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> |
