| <!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/arc-swap-1.6.0/src/access.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>access.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="../../arc_swap/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="../../arc_swap/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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| <span id="523">523</span> |
| <span id="524">524</span> |
| <span id="525">525</span> |
| <span id="526">526</span> |
| <span id="527">527</span> |
| <span id="528">528</span> |
| <span id="529">529</span> |
| <span id="530">530</span> |
| <span id="531">531</span> |
| <span id="532">532</span> |
| <span id="533">533</span> |
| <span id="534">534</span> |
| <span id="535">535</span> |
| <span id="536">536</span> |
| <span id="537">537</span> |
| <span id="538">538</span> |
| <span id="539">539</span> |
| <span id="540">540</span> |
| <span id="541">541</span> |
| <span id="542">542</span> |
| <span id="543">543</span> |
| <span id="544">544</span> |
| </pre><pre class="rust"><code><span class="attribute">#![deny(unsafe_code)] |
| |
| </span><span class="doccomment">//! Abstracting over accessing parts of stored value. |
| //! |
| //! Sometimes, there's a big globalish data structure (like a configuration for the whole program). |
| //! Then there are parts of the program that need access to up-to-date version of their *part* of |
| //! the configuration, but for reasons of code separation and reusability, it is not desirable to |
| //! pass the whole configuration to each of the parts. |
| //! |
| //! This module provides means to grant the parts access to the relevant subsets of such global |
| //! data structure while masking the fact it is part of the bigger whole from the component. |
| //! |
| //! Note that the [`cache`][crate::cache] module has its own [`Access`][crate::cache::Access] trait |
| //! that serves a similar purpose, but with cached access. The signatures are different, therefore |
| //! an incompatible trait. |
| //! |
| //! # The general idea |
| //! |
| //! Each part of the code accepts generic [`Access<T>`][Access] for the `T` of its interest. This |
| //! provides means to load current version of the structure behind the scenes and get only the |
| //! relevant part, without knowing what the big structure is. |
| //! |
| //! For technical reasons, the [`Access`] trait is not object safe. If type erasure is desired, it |
| //! is possible use the [`DynAccess`][crate::access::DynAccess] instead, which is object safe, but |
| //! slightly slower. |
| //! |
| //! For some cases, it is possible to use [`ArcSwapAny::map`]. If that is not flexible enough, the |
| //! [`Map`] type can be created directly. |
| //! |
| //! Note that the [`Access`] trait is also implemented for [`ArcSwapAny`] itself. Additionally, |
| //! there's the [`Constant`][crate::access::Constant] helper type, which is useful mostly for |
| //! testing (it doesn't allow reloading). |
| //! |
| //! # Performance |
| //! |
| //! In general, these utilities use [`ArcSwapAny::load`] internally and then apply the provided |
| //! transformation. This has several consequences: |
| //! |
| //! * Limitations of the [`load`][ArcSwapAny::load] apply ‒ including the recommendation to not |
| //! hold the returned guard object for too long, but long enough to get consistency. |
| //! * The transformation should be cheap ‒ optimally just borrowing into the structure. |
| //! |
| //! # Examples |
| //! |
| //! ```rust |
| //! use std::sync::Arc; |
| //! use std::thread::{self, JoinHandle}; |
| //! use std::time::Duration; |
| //! |
| //! use arc_swap::ArcSwap; |
| //! use arc_swap::access::{Access, Constant, Map}; |
| //! |
| //! fn work_with_usize<A: Access<usize> + Send + 'static>(a: A) -> JoinHandle<()> { |
| //! thread::spawn(move || { |
| //! let mut value = 0; |
| //! while value != 42 { |
| //! let guard = a.load(); |
| //! value = *guard; |
| //! println!("{}", value); |
| //! // Not strictly necessary, but dropping the guard can free some resources, like |
| //! // slots for tracking what values are still in use. We do it before the sleeping, |
| //! // not at the end of the scope. |
| //! drop(guard); |
| //! thread::sleep(Duration::from_millis(50)); |
| //! } |
| //! }) |
| //! } |
| //! |
| //! // Passing the whole thing directly |
| //! // (If we kept another Arc to it, we could change the value behind the scenes) |
| //! work_with_usize(Arc::new(ArcSwap::from_pointee(42))).join().unwrap(); |
| //! |
| //! // Passing a subset of a structure |
| //! struct Cfg { |
| //! value: usize, |
| //! } |
| //! |
| //! let cfg = Arc::new(ArcSwap::from_pointee(Cfg { value: 0 })); |
| //! let thread = work_with_usize(Map::new(Arc::clone(&cfg), |cfg: &Cfg| &cfg.value)); |
| //! cfg.store(Arc::new(Cfg { value: 42 })); |
| //! thread.join().unwrap(); |
| //! |
| //! // Passing a constant that can't change. Useful mostly for testing purposes. |
| //! work_with_usize(Constant(42)).join().unwrap(); |
| //! ``` |
| |
| </span><span class="kw">use </span>std::marker::PhantomData; |
| <span class="kw">use </span>std::ops::Deref; |
| <span class="kw">use </span>std::rc::Rc; |
| <span class="kw">use </span>std::sync::Arc; |
| |
| <span class="kw">use </span><span class="kw">super</span>::ref_cnt::RefCnt; |
| <span class="kw">use </span><span class="kw">super</span>::strategy::Strategy; |
| <span class="kw">use super</span>::{ArcSwapAny, Guard}; |
| |
| <span class="doccomment">/// Abstracts over ways code can get access to a value of type `T`. |
| /// |
| /// This is the trait that parts of code will use when accessing a subpart of the big data |
| /// structure. See the [module documentation](index.html) for details. |
| </span><span class="kw">pub trait </span>Access<T> { |
| <span class="doccomment">/// A guard object containing the value and keeping it alive. |
| /// |
| /// For technical reasons, the library doesn't allow direct access into the stored value. A |
| /// temporary guard object must be loaded, that keeps the actual value alive for the time of |
| /// use. |
| </span><span class="kw">type </span>Guard: Deref<Target = T>; |
| |
| <span class="doccomment">/// The loading method. |
| /// |
| /// This returns the guard that holds the actual value. Should be called anew each time a fresh |
| /// value is needed. |
| </span><span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard; |
| } |
| |
| <span class="kw">impl</span><T, A: Access<T> + <span class="question-mark">?</span>Sized, P: Deref<Target = A>> Access<T> <span class="kw">for </span>P { |
| <span class="kw">type </span>Guard = A::Guard; |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| <span class="self">self</span>.deref().load() |
| } |
| } |
| |
| <span class="kw">impl</span><T> Access<T> <span class="kw">for dyn </span>DynAccess<T> + <span class="lifetime">'_ </span>{ |
| <span class="kw">type </span>Guard = DynGuard<T>; |
| |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| <span class="self">self</span>.load() |
| } |
| } |
| |
| <span class="kw">impl</span><T> Access<T> <span class="kw">for dyn </span>DynAccess<T> + <span class="lifetime">'_ </span>+ Send { |
| <span class="kw">type </span>Guard = DynGuard<T>; |
| |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| <span class="self">self</span>.load() |
| } |
| } |
| |
| <span class="kw">impl</span><T> Access<T> <span class="kw">for dyn </span>DynAccess<T> + <span class="lifetime">'_ </span>+ Sync + Send { |
| <span class="kw">type </span>Guard = DynGuard<T>; |
| |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| <span class="self">self</span>.load() |
| } |
| } |
| |
| <span class="kw">impl</span><T: RefCnt, S: Strategy<T>> Access<T> <span class="kw">for </span>ArcSwapAny<T, S> { |
| <span class="kw">type </span>Guard = Guard<T, S>; |
| |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| <span class="self">self</span>.load() |
| } |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| #[doc(hidden)] |
| </span><span class="kw">pub struct </span>DirectDeref<T: RefCnt, S: Strategy<T>>(Guard<T, S>); |
| |
| <span class="kw">impl</span><T, S: Strategy<Arc<T>>> Deref <span class="kw">for </span>DirectDeref<Arc<T>, S> { |
| <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="self">self</span>.<span class="number">0</span>.deref().deref() |
| } |
| } |
| |
| <span class="kw">impl</span><T, S: Strategy<Arc<T>>> Access<T> <span class="kw">for </span>ArcSwapAny<Arc<T>, S> { |
| <span class="kw">type </span>Guard = DirectDeref<Arc<T>, S>; |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| DirectDeref(<span class="self">self</span>.load()) |
| } |
| } |
| |
| <span class="kw">impl</span><T, S: Strategy<Rc<T>>> Deref <span class="kw">for </span>DirectDeref<Rc<T>, S> { |
| <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="self">self</span>.<span class="number">0</span>.deref().deref() |
| } |
| } |
| |
| <span class="kw">impl</span><T, S: Strategy<Rc<T>>> Access<T> <span class="kw">for </span>ArcSwapAny<Rc<T>, S> { |
| <span class="kw">type </span>Guard = DirectDeref<Rc<T>, S>; |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| DirectDeref(<span class="self">self</span>.load()) |
| } |
| } |
| |
| <span class="attribute">#[doc(hidden)] |
| </span><span class="kw">pub struct </span>DynGuard<T: <span class="question-mark">?</span>Sized>(Box<<span class="kw">dyn </span>Deref<Target = T>>); |
| |
| <span class="kw">impl</span><T: <span class="question-mark">?</span>Sized> Deref <span class="kw">for </span>DynGuard<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-2">&</span><span class="self">self</span>.<span class="number">0 |
| </span>} |
| } |
| |
| <span class="doccomment">/// An object-safe version of the [`Access`] trait. |
| /// |
| /// This can be used instead of the [`Access`] trait in case a type erasure is desired. This has |
| /// the effect of performance hit (due to boxing of the result and due to dynamic dispatch), but |
| /// makes certain code simpler and possibly makes the executable smaller. |
| /// |
| /// This is automatically implemented for everything that implements [`Access`]. |
| /// |
| /// # Examples |
| /// |
| /// ```rust |
| /// use arc_swap::access::{Constant, DynAccess}; |
| /// |
| /// fn do_something(value: Box<dyn DynAccess<usize> + Send>) { |
| /// let v = value.load(); |
| /// println!("{}", *v); |
| /// } |
| /// |
| /// do_something(Box::new(Constant(42))); |
| /// ``` |
| </span><span class="kw">pub trait </span>DynAccess<T> { |
| <span class="doccomment">/// The equivalent of [`Access::load`]. |
| </span><span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> DynGuard<T>; |
| } |
| |
| <span class="kw">impl</span><T, A> DynAccess<T> <span class="kw">for </span>A |
| <span class="kw">where |
| </span>A: Access<T>, |
| A::Guard: <span class="lifetime">'static</span>, |
| { |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> DynGuard<T> { |
| DynGuard(Box::new(Access::load(<span class="self">self</span>))) |
| } |
| } |
| |
| <span class="doccomment">/// [DynAccess] to [Access] wrapper. |
| /// |
| /// In previous versions, `Box<dyn DynAccess>` didn't implement [Access], to use inside [Map] one |
| /// could use this wrapper. Since then, a way was found to solve it. In most cases, this wrapper is |
| /// no longer necessary. |
| /// |
| /// This is left in place for two reasons: |
| /// * Backwards compatibility. |
| /// * Corner-cases not covered by the found solution. For example, trait inheritance in the form of |
| /// `Box<dyn SomeTrait>` where `SomeTrait: Access` doesn't work out of the box and still needs |
| /// this wrapper. |
| /// |
| /// # Examples |
| /// |
| /// The example is for the simple case (which is no longer needed, but may help as an inspiration). |
| /// |
| /// ```rust |
| /// use std::sync::Arc; |
| /// |
| /// use arc_swap::ArcSwap; |
| /// use arc_swap::access::{AccessConvert, DynAccess, Map}; |
| /// |
| /// struct Inner { |
| /// val: usize, |
| /// } |
| /// |
| /// struct Middle { |
| /// inner: Inner, |
| /// } |
| /// |
| /// struct Outer { |
| /// middle: Middle, |
| /// } |
| /// |
| /// let outer = Arc::new(ArcSwap::from_pointee(Outer { |
| /// middle: Middle { |
| /// inner: Inner { |
| /// val: 42, |
| /// } |
| /// } |
| /// })); |
| /// |
| /// let middle: Arc<dyn DynAccess<Middle>> = |
| /// Arc::new(Map::new(outer, |outer: &Outer| &outer.middle)); |
| /// let inner: Arc<dyn DynAccess<Inner>> = |
| /// Arc::new(Map::new(AccessConvert(middle), |middle: &Middle| &middle.inner)); |
| /// let guard = inner.load(); |
| /// assert_eq!(42, guard.val); |
| /// ``` |
| </span><span class="kw">pub struct </span>AccessConvert<D>(<span class="kw">pub </span>D); |
| |
| <span class="kw">impl</span><T, D> Access<T> <span class="kw">for </span>AccessConvert<D> |
| <span class="kw">where |
| </span>D: Deref, |
| D::Target: DynAccess<T>, |
| { |
| <span class="kw">type </span>Guard = DynGuard<T>; |
| |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| <span class="self">self</span>.<span class="number">0</span>.load() |
| } |
| } |
| |
| <span class="attribute">#[doc(hidden)] |
| #[derive(Copy, Clone, Debug)] |
| </span><span class="kw">pub struct </span>MapGuard<G, F, T, R> { |
| guard: G, |
| projection: F, |
| _t: PhantomData<<span class="kw">fn</span>(<span class="kw-2">&</span>T) -> <span class="kw-2">&</span>R>, |
| } |
| |
| <span class="kw">impl</span><G, F, T, R> Deref <span class="kw">for </span>MapGuard<G, F, T, R> |
| <span class="kw">where |
| </span>G: Deref<Target = T>, |
| F: Fn(<span class="kw-2">&</span>T) -> <span class="kw-2">&</span>R, |
| { |
| <span class="kw">type </span>Target = R; |
| <span class="kw">fn </span>deref(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>R { |
| (<span class="self">self</span>.projection)(<span class="kw-2">&</span><span class="self">self</span>.guard) |
| } |
| } |
| |
| <span class="doccomment">/// An adaptor to provide access to a part of larger structure. |
| /// |
| /// This is the *active* part of this module. Use the [module documentation](index.html) for the |
| /// details. |
| </span><span class="attribute">#[derive(Copy, Clone, Debug)] |
| </span><span class="kw">pub struct </span>Map<A, T, F> { |
| access: A, |
| projection: F, |
| _t: PhantomData<<span class="kw">fn</span>() -> T>, |
| } |
| |
| <span class="kw">impl</span><A, T, F> Map<A, T, F> { |
| <span class="doccomment">/// Creates a new instance. |
| /// |
| /// # Parameters |
| /// |
| /// * `access`: Access to the bigger structure. This is usually something like `Arc<ArcSwap>` |
| /// or `&ArcSwap`. It is technically possible to use any other [`Access`] here, though, for |
| /// example to sub-delegate into even smaller structure from a [`Map`] (or generic |
| /// [`Access`]). |
| /// * `projection`: A function (or closure) responsible to providing a reference into the |
| /// bigger bigger structure, selecting just subset of it. In general, it is expected to be |
| /// *cheap* (like only taking reference). |
| </span><span class="kw">pub fn </span>new<R>(access: A, projection: F) -> <span class="self">Self |
| </span><span class="kw">where |
| </span>F: Fn(<span class="kw-2">&</span>T) -> <span class="kw-2">&</span>R + Clone, |
| { |
| Map { |
| access, |
| projection, |
| _t: PhantomData, |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><A, F, T, R> Access<R> <span class="kw">for </span>Map<A, T, F> |
| <span class="kw">where |
| </span>A: Access<T>, |
| F: Fn(<span class="kw-2">&</span>T) -> <span class="kw-2">&</span>R + Clone, |
| { |
| <span class="kw">type </span>Guard = MapGuard<A::Guard, F, T, R>; |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| <span class="kw">let </span>guard = <span class="self">self</span>.access.load(); |
| MapGuard { |
| guard, |
| projection: <span class="self">self</span>.projection.clone(), |
| _t: PhantomData, |
| } |
| } |
| } |
| |
| <span class="attribute">#[doc(hidden)] |
| #[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)] |
| </span><span class="kw">pub struct </span>ConstantDeref<T>(T); |
| |
| <span class="kw">impl</span><T> Deref <span class="kw">for </span>ConstantDeref<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-2">&</span><span class="self">self</span>.<span class="number">0 |
| </span>} |
| } |
| |
| <span class="doccomment">/// Access to an constant. |
| /// |
| /// This wraps a constant value to provide [`Access`] to it. It is constant in the sense that, |
| /// unlike [`ArcSwapAny`] and [`Map`], the loaded value will always stay the same (there's no |
| /// remote `store`). |
| /// |
| /// The purpose is mostly testing and plugging a parameter that works generically from code that |
| /// doesn't need the updating functionality. |
| </span><span class="attribute">#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)] |
| </span><span class="kw">pub struct </span>Constant<T>(<span class="kw">pub </span>T); |
| |
| <span class="kw">impl</span><T: Clone> Access<T> <span class="kw">for </span>Constant<T> { |
| <span class="kw">type </span>Guard = ConstantDeref<T>; |
| <span class="kw">fn </span>load(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Guard { |
| ConstantDeref(<span class="self">self</span>.<span class="number">0</span>.clone()) |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| <span class="kw">use </span><span class="kw">super</span>::<span class="kw">super</span>::{ArcSwap, ArcSwapOption}; |
| |
| <span class="kw">use super</span>::<span class="kw-2">*</span>; |
| |
| <span class="kw">fn </span>check_static_dispatch_direct<A: Access<usize>>(a: A) { |
| <span class="macro">assert_eq!</span>(<span class="number">42</span>, <span class="kw-2">*</span>a.load()); |
| } |
| |
| <span class="kw">fn </span>check_static_dispatch<A: Access<Arc<usize>>>(a: A) { |
| <span class="macro">assert_eq!</span>(<span class="number">42</span>, <span class="kw-2">**</span>a.load()); |
| } |
| |
| <span class="doccomment">/// Tests dispatching statically from arc-swap works |
| </span><span class="attribute">#[test] |
| </span><span class="kw">fn </span>static_dispatch() { |
| <span class="kw">let </span>a = ArcSwap::from_pointee(<span class="number">42</span>); |
| check_static_dispatch_direct(<span class="kw-2">&</span>a); |
| check_static_dispatch(<span class="kw-2">&</span>a); |
| check_static_dispatch(a); |
| } |
| |
| <span class="kw">fn </span>check_dyn_dispatch_direct(a: <span class="kw-2">&</span><span class="kw">dyn </span>DynAccess<usize>) { |
| <span class="macro">assert_eq!</span>(<span class="number">42</span>, <span class="kw-2">*</span>a.load()); |
| } |
| |
| <span class="kw">fn </span>check_dyn_dispatch(a: <span class="kw-2">&</span><span class="kw">dyn </span>DynAccess<Arc<usize>>) { |
| <span class="macro">assert_eq!</span>(<span class="number">42</span>, <span class="kw-2">**</span>a.load()); |
| } |
| |
| <span class="doccomment">/// Tests we can also do a dynamic dispatch of the companion trait |
| </span><span class="attribute">#[test] |
| </span><span class="kw">fn </span>dyn_dispatch() { |
| <span class="kw">let </span>a = ArcSwap::from_pointee(<span class="number">42</span>); |
| check_dyn_dispatch_direct(<span class="kw-2">&</span>a); |
| check_dyn_dispatch(<span class="kw-2">&</span>a); |
| } |
| |
| <span class="kw">fn </span>check_transition<A>(a: A) |
| <span class="kw">where |
| </span>A: Access<usize>, |
| A::Guard: <span class="lifetime">'static</span>, |
| { |
| check_dyn_dispatch_direct(<span class="kw-2">&</span>a) |
| } |
| |
| <span class="doccomment">/// Tests we can easily transition from the static dispatch trait to the dynamic one |
| </span><span class="attribute">#[test] |
| </span><span class="kw">fn </span>transition() { |
| <span class="kw">let </span>a = ArcSwap::from_pointee(<span class="number">42</span>); |
| check_transition(<span class="kw-2">&</span>a); |
| check_transition(a); |
| } |
| |
| <span class="doccomment">/// Test we can dispatch from Arc<ArcSwap<_>> or similar. |
| </span><span class="attribute">#[test] |
| </span><span class="kw">fn </span>indirect() { |
| <span class="kw">let </span>a = Arc::new(ArcSwap::from_pointee(<span class="number">42</span>)); |
| check_static_dispatch(<span class="kw-2">&</span>a); |
| check_dyn_dispatch(<span class="kw-2">&</span>a); |
| } |
| |
| <span class="kw">struct </span>Cfg { |
| value: usize, |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>map() { |
| <span class="kw">let </span>a = ArcSwap::from_pointee(Cfg { value: <span class="number">42 </span>}); |
| <span class="kw">let </span>map = a.map(|a: <span class="kw-2">&</span>Cfg| <span class="kw-2">&</span>a.value); |
| check_static_dispatch_direct(<span class="kw-2">&</span>map); |
| check_dyn_dispatch_direct(<span class="kw-2">&</span>map); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>map_option_some() { |
| <span class="kw">let </span>a = ArcSwapOption::from_pointee(Cfg { value: <span class="number">42 </span>}); |
| <span class="kw">let </span>map = a.map(|a: <span class="kw-2">&</span><span class="prelude-ty">Option</span><Arc<Cfg>>| a.as_ref().map(|c| <span class="kw-2">&</span>c.value).unwrap()); |
| check_static_dispatch_direct(<span class="kw-2">&</span>map); |
| check_dyn_dispatch_direct(<span class="kw-2">&</span>map); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>map_option_none() { |
| <span class="kw">let </span>a = ArcSwapOption::empty(); |
| <span class="kw">let </span>map = a.map(|a: <span class="kw-2">&</span><span class="prelude-ty">Option</span><Arc<Cfg>>| a.as_ref().map(|c| <span class="kw-2">&</span>c.value).unwrap_or(<span class="kw-2">&</span><span class="number">42</span>)); |
| check_static_dispatch_direct(<span class="kw-2">&</span>map); |
| check_dyn_dispatch_direct(<span class="kw-2">&</span>map); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>constant() { |
| <span class="kw">let </span>c = Constant(<span class="number">42</span>); |
| check_static_dispatch_direct(c); |
| check_dyn_dispatch_direct(<span class="kw-2">&</span>c); |
| check_static_dispatch_direct(c); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>map_reload() { |
| <span class="kw">let </span>a = ArcSwap::from_pointee(Cfg { value: <span class="number">0 </span>}); |
| <span class="kw">let </span>map = a.map(|cfg: <span class="kw-2">&</span>Cfg| <span class="kw-2">&</span>cfg.value); |
| <span class="macro">assert_eq!</span>(<span class="number">0</span>, <span class="kw-2">*</span>Access::load(<span class="kw-2">&</span>map)); |
| a.store(Arc::new(Cfg { value: <span class="number">42 </span>})); |
| <span class="macro">assert_eq!</span>(<span class="number">42</span>, <span class="kw-2">*</span>Access::load(<span class="kw-2">&</span>map)); |
| } |
| |
| <span class="comment">// Compile tests for dynamic access |
| </span><span class="kw">fn </span>_expect_access<T>(<span class="kw">_</span>: <span class="kw">impl </span>Access<T>) {} |
| |
| <span class="kw">fn </span>_dyn_access<T>(x: Box<<span class="kw">dyn </span>DynAccess<T> + <span class="lifetime">'_</span>>) { |
| _expect_access(x) |
| } |
| |
| <span class="kw">fn </span>_dyn_access_send<T>(x: Box<<span class="kw">dyn </span>DynAccess<T> + <span class="lifetime">'_ </span>+ Send>) { |
| _expect_access(x) |
| } |
| |
| <span class="kw">fn </span>_dyn_access_send_sync<T>(x: Box<<span class="kw">dyn </span>DynAccess<T> + <span class="lifetime">'_ </span>+ Send + Sync>) { |
| _expect_access(x) |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>double_dyn_access_complex() { |
| <span class="kw">struct </span>Inner { |
| val: usize, |
| } |
| |
| <span class="kw">struct </span>Middle { |
| inner: Inner, |
| } |
| |
| <span class="kw">struct </span>Outer { |
| middle: Middle, |
| } |
| |
| <span class="kw">let </span>outer = Arc::new(ArcSwap::from_pointee(Outer { |
| middle: Middle { |
| inner: Inner { val: <span class="number">42 </span>}, |
| }, |
| })); |
| |
| <span class="kw">let </span>middle: Arc<<span class="kw">dyn </span>DynAccess<Middle>> = |
| Arc::new(Map::new(outer, |outer: <span class="kw-2">&</span>Outer| <span class="kw-2">&</span>outer.middle)); |
| <span class="kw">let </span>inner: Arc<<span class="kw">dyn </span>DynAccess<Inner>> = |
| Arc::new(Map::new(middle, |middle: <span class="kw-2">&</span>Middle| <span class="kw-2">&</span>middle.inner)); |
| <span class="comment">// Damn. We have the DynAccess wrapper in scope and need to disambiguate the inner.load() |
| </span><span class="kw">let </span>guard = Access::load(<span class="kw-2">&</span>inner); |
| <span class="macro">assert_eq!</span>(<span class="number">42</span>, guard.val); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="arc_swap" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
