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</pre><pre class="rust">
<span class="comment">// Necessary for implementing atomic methods for `AtomicUnit`</span>
<span class="attribute">#![<span class="ident">allow</span>(<span class="ident">clippy::unit_arg</span>)]</span>
<span class="attribute">#![<span class="ident">allow</span>(<span class="ident">clippy::let_unit_value</span>)]</span>
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::primitive::sync::atomic</span>::{<span class="self">self</span>, <span class="ident">AtomicBool</span>};
<span class="kw">use</span> <span class="ident">core::cell::UnsafeCell</span>;
<span class="kw">use</span> <span class="ident">core::fmt</span>;
<span class="kw">use</span> <span class="ident">core::mem</span>;
<span class="kw">use</span> <span class="ident">core::sync::atomic::Ordering</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">crossbeam_loom</span>))]</span>
<span class="kw">use</span> <span class="ident">core::ptr</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span>
<span class="kw">use</span> <span class="ident">std::panic</span>::{<span class="ident">RefUnwindSafe</span>, <span class="ident">UnwindSafe</span>};
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">crossbeam_loom</span>))]</span>
<span class="kw">use</span> <span class="kw">super</span><span class="ident">::seq_lock::SeqLock</span>;
<span class="doccomment">/// A thread-safe mutable memory location.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This type is equivalent to [`Cell`], except it can also be shared among multiple threads.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Operations on `AtomicCell`s use atomic instructions whenever possible, and synchronize using</span>
<span class="doccomment">/// global locks otherwise. You can call [`AtomicCell::<T>::is_lock_free()`] to check whether</span>
<span class="doccomment">/// atomic instructions or locks will be used.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Atomic loads use the [`Acquire`] ordering and atomic stores use the [`Release`] ordering.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`Cell`]: std::cell::Cell</span>
<span class="doccomment">/// [`AtomicCell::<T>::is_lock_free()`]: AtomicCell::is_lock_free</span>
<span class="doccomment">/// [`Acquire`]: std::sync::atomic::Ordering::Acquire</span>
<span class="doccomment">/// [`Release`]: std::sync::atomic::Ordering::Release</span>
<span class="attribute">#[<span class="ident">repr</span>(<span class="ident">transparent</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> {
<span class="doccomment">/// The inner value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If this value can be transmuted into a primitive atomic type, it will be treated as such.</span>
<span class="doccomment">/// Otherwise, all potentially concurrent operations on this data will be protected by a global</span>
<span class="doccomment">/// lock.</span>
<span class="ident">value</span>: <span class="ident">UnsafeCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>,
}
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">Send</span> <span class="kw">for</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">Sync</span> <span class="kw">for</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span>
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">UnwindSafe</span> <span class="kw">for</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span>
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">RefUnwindSafe</span> <span class="kw">for</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Creates a new atomic cell initialized with `val`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(7);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">const</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">val</span>: <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">AtomicCell</span> {
<span class="ident">value</span>: <span class="ident">UnsafeCell::new</span>(<span class="ident">val</span>),
}
}
<span class="doccomment">/// Consumes the atomic and returns the contained value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(7);</span>
<span class="doccomment">/// let v = a.into_inner();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(v, 7);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_inner</span>(<span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">T</span> {
<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">into_inner</span>()
}
<span class="doccomment">/// Returns `true` if operations on values of this type are lock-free.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the compiler or the platform doesn't support the necessary atomic instructions,</span>
<span class="doccomment">/// `AtomicCell<T>` will use global locks for every potentially concurrent atomic operation.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // This type is internally represented as `AtomicUsize` so we can just use atomic</span>
<span class="doccomment">/// // operations provided by it.</span>
<span class="doccomment">/// assert_eq!(AtomicCell::<usize>::is_lock_free(), true);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // A wrapper struct around `isize`.</span>
<span class="doccomment">/// struct Foo {</span>
<span class="doccomment">/// bar: isize,</span>
<span class="doccomment">/// }</span>
<span class="doccomment">/// // `AtomicCell<Foo>` will be internally represented as `AtomicIsize`.</span>
<span class="doccomment">/// assert_eq!(AtomicCell::<Foo>::is_lock_free(), true);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // Operations on zero-sized types are always lock-free.</span>
<span class="doccomment">/// assert_eq!(AtomicCell::<()>::is_lock_free(), true);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // Very large types cannot be represented as any of the standard atomic types, so atomic</span>
<span class="doccomment">/// // operations on them will have to use global locks for synchronization.</span>
<span class="doccomment">/// assert_eq!(AtomicCell::<[u8; 1000]>::is_lock_free(), false);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">const</span> <span class="kw">fn</span> <span class="ident">is_lock_free</span>() <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="ident">atomic_is_lock_free</span>::<span class="op"><</span><span class="ident">T</span><span class="op">></span>()
}
<span class="doccomment">/// Stores `val` into the atomic cell.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(7);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.load(), 7);</span>
<span class="doccomment">/// a.store(8);</span>
<span class="doccomment">/// assert_eq!(a.load(), 8);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">store</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="ident">T</span>) {
<span class="kw">if</span> <span class="ident">mem::needs_drop</span>::<span class="op"><</span><span class="ident">T</span><span class="op">></span>() {
<span class="ident">drop</span>(<span class="self">self</span>.<span class="ident">swap</span>(<span class="ident">val</span>));
} <span class="kw">else</span> {
<span class="kw">unsafe</span> {
<span class="ident">atomic_store</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>(), <span class="ident">val</span>);
}
}
}
<span class="doccomment">/// Stores `val` into the atomic cell and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(7);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.load(), 7);</span>
<span class="doccomment">/// assert_eq!(a.swap(8), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 8);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">swap</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="ident">T</span> {
<span class="kw">unsafe</span> { <span class="ident">atomic_swap</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>(), <span class="ident">val</span>) }
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Returns a raw pointer to the underlying data in this atomic cell.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(5);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let ptr = a.as_ptr();</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">as_ptr</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">T</span> {
<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>()
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Default</span><span class="op">></span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Takes the value of the atomic cell, leaving `Default::default()` in its place.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(5);</span>
<span class="doccomment">/// let five = a.take();</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(five, 5);</span>
<span class="doccomment">/// assert_eq!(a.into_inner(), 0);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">take</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">T</span> {
<span class="self">self</span>.<span class="ident">swap</span>(<span class="ident">Default::default</span>())
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Copy</span><span class="op">></span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Loads a value from the atomic cell.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(7);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.load(), 7);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">load</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">T</span> {
<span class="kw">unsafe</span> { <span class="ident">atomic_load</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>()) }
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Copy</span> <span class="op">+</span> <span class="ident">Eq</span><span class="op">></span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// If the current value equals `current`, stores `new` into the atomic cell.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The return value is always the previous value. If it is equal to `current`, then the value</span>
<span class="doccomment">/// was updated.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// # #![allow(deprecated)]</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(1);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.compare_and_swap(2, 3), 1);</span>
<span class="doccomment">/// assert_eq!(a.load(), 1);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.compare_and_swap(1, 2), 1);</span>
<span class="doccomment">/// assert_eq!(a.load(), 2);</span>
<span class="doccomment">/// ```</span>
<span class="comment">// TODO: remove in the next major version.</span>
<span class="attribute">#[<span class="ident">deprecated</span>(<span class="ident">note</span> <span class="op">=</span> <span class="string">"Use `compare_exchange` instead"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">compare_and_swap</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">current</span>: <span class="ident">T</span>, <span class="ident">new</span>: <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="ident">T</span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">compare_exchange</span>(<span class="ident">current</span>, <span class="ident">new</span>) {
<span class="prelude-val">Ok</span>(<span class="ident">v</span>) <span class="op">=</span><span class="op">></span> <span class="ident">v</span>,
<span class="prelude-val">Err</span>(<span class="ident">v</span>) <span class="op">=</span><span class="op">></span> <span class="ident">v</span>,
}
}
<span class="doccomment">/// If the current value equals `current`, stores `new` into the atomic cell.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The return value is a result indicating whether the new value was written and containing</span>
<span class="doccomment">/// the previous value. On success this value is guaranteed to be equal to `current`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(1);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.compare_exchange(2, 3), Err(1));</span>
<span class="doccomment">/// assert_eq!(a.load(), 1);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.compare_exchange(1, 2), Ok(1));</span>
<span class="doccomment">/// assert_eq!(a.load(), 2);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">compare_exchange</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">current</span>: <span class="ident">T</span>, <span class="ident">new</span>: <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span>, <span class="ident">T</span><span class="op">></span> {
<span class="kw">unsafe</span> { <span class="ident">atomic_compare_exchange_weak</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>(), <span class="ident">current</span>, <span class="ident">new</span>) }
}
<span class="doccomment">/// Fetches the value, and applies a function to it that returns an optional</span>
<span class="doccomment">/// new value. Returns a `Result` of `Ok(previous_value)` if the function returned `Some(_)`, else</span>
<span class="doccomment">/// `Err(previous_value)`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note: This may call the function multiple times if the value has been changed from other threads in</span>
<span class="doccomment">/// the meantime, as long as the function returns `Some(_)`, but the function will have been applied</span>
<span class="doccomment">/// only once to the stored value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(7);</span>
<span class="doccomment">/// assert_eq!(a.fetch_update(|_| None), Err(7));</span>
<span class="doccomment">/// assert_eq!(a.fetch_update(|a| Some(a + 1)), Ok(7));</span>
<span class="doccomment">/// assert_eq!(a.fetch_update(|a| Some(a + 1)), Ok(8));</span>
<span class="doccomment">/// assert_eq!(a.load(), 9);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_update</span><span class="op"><</span><span class="ident">F</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="kw-2">mut</span> <span class="ident">f</span>: <span class="ident">F</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span>, <span class="ident">T</span><span class="op">></span>
<span class="kw">where</span>
<span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>,
{
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">prev</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">load</span>();
<span class="kw">while</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">next</span>) <span class="op">=</span> <span class="ident">f</span>(<span class="ident">prev</span>) {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">compare_exchange</span>(<span class="ident">prev</span>, <span class="ident">next</span>) {
<span class="ident">x</span> @ <span class="prelude-val">Ok</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="kw">return</span> <span class="ident">x</span>,
<span class="prelude-val">Err</span>(<span class="ident">next_prev</span>) <span class="op">=</span><span class="op">></span> <span class="ident">prev</span> <span class="op">=</span> <span class="ident">next_prev</span>,
}
}
<span class="prelude-val">Err</span>(<span class="ident">prev</span>)
}
}
<span class="macro">macro_rules!</span> <span class="ident">impl_arithmetic</span> {
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">ty</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>:<span class="ident">tt</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">impl</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span><span class="op">></span> {
<span class="doccomment">/// Increments the current value by `val` and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The addition wraps on overflow.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_add(3), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 10);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_add</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">if</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicUsize</span><span class="op">></span>() {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">atomic::AtomicUsize</span>) };
<span class="ident">a</span>.<span class="ident">fetch_add</span>(<span class="ident">val</span> <span class="kw">as</span> <span class="ident">usize</span>, <span class="ident">Ordering::AcqRel</span>) <span class="kw">as</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>
} <span class="kw">else</span> {
<span class="kw">let</span> <span class="ident">_guard</span> <span class="op">=</span> <span class="ident">lock</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="ident">usize</span>).<span class="ident">write</span>();
<span class="kw">let</span> <span class="ident">value</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>()) };
<span class="kw">let</span> <span class="ident">old</span> <span class="op">=</span> <span class="kw-2">*</span><span class="ident">value</span>;
<span class="kw-2">*</span><span class="ident">value</span> <span class="op">=</span> <span class="ident">value</span>.<span class="ident">wrapping_add</span>(<span class="ident">val</span>);
<span class="ident">old</span>
}
}
<span class="doccomment">/// Decrements the current value by `val` and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The subtraction wraps on overflow.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_sub(3), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 4);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_sub</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">if</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicUsize</span><span class="op">></span>() {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">atomic::AtomicUsize</span>) };
<span class="ident">a</span>.<span class="ident">fetch_sub</span>(<span class="ident">val</span> <span class="kw">as</span> <span class="ident">usize</span>, <span class="ident">Ordering::AcqRel</span>) <span class="kw">as</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>
} <span class="kw">else</span> {
<span class="kw">let</span> <span class="ident">_guard</span> <span class="op">=</span> <span class="ident">lock</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="ident">usize</span>).<span class="ident">write</span>();
<span class="kw">let</span> <span class="ident">value</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>()) };
<span class="kw">let</span> <span class="ident">old</span> <span class="op">=</span> <span class="kw-2">*</span><span class="ident">value</span>;
<span class="kw-2">*</span><span class="ident">value</span> <span class="op">=</span> <span class="ident">value</span>.<span class="ident">wrapping_sub</span>(<span class="ident">val</span>);
<span class="ident">old</span>
}
}
<span class="doccomment">/// Applies bitwise "and" to the current value and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_and(3), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 3);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_and</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">if</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicUsize</span><span class="op">></span>() {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">atomic::AtomicUsize</span>) };
<span class="ident">a</span>.<span class="ident">fetch_and</span>(<span class="ident">val</span> <span class="kw">as</span> <span class="ident">usize</span>, <span class="ident">Ordering::AcqRel</span>) <span class="kw">as</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>
} <span class="kw">else</span> {
<span class="kw">let</span> <span class="ident">_guard</span> <span class="op">=</span> <span class="ident">lock</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="ident">usize</span>).<span class="ident">write</span>();
<span class="kw">let</span> <span class="ident">value</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>()) };
<span class="kw">let</span> <span class="ident">old</span> <span class="op">=</span> <span class="kw-2">*</span><span class="ident">value</span>;
<span class="kw-2">*</span><span class="ident">value</span> <span class="op">&=</span> <span class="ident">val</span>;
<span class="ident">old</span>
}
}
<span class="doccomment">/// Applies bitwise "or" to the current value and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_or(16), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 23);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_or</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">if</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicUsize</span><span class="op">></span>() {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">atomic::AtomicUsize</span>) };
<span class="ident">a</span>.<span class="ident">fetch_or</span>(<span class="ident">val</span> <span class="kw">as</span> <span class="ident">usize</span>, <span class="ident">Ordering::AcqRel</span>) <span class="kw">as</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>
} <span class="kw">else</span> {
<span class="kw">let</span> <span class="ident">_guard</span> <span class="op">=</span> <span class="ident">lock</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="ident">usize</span>).<span class="ident">write</span>();
<span class="kw">let</span> <span class="ident">value</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>()) };
<span class="kw">let</span> <span class="ident">old</span> <span class="op">=</span> <span class="kw-2">*</span><span class="ident">value</span>;
<span class="kw-2">*</span><span class="ident">value</span> <span class="op">|</span><span class="op">=</span> <span class="ident">val</span>;
<span class="ident">old</span>
}
}
<span class="doccomment">/// Applies bitwise "xor" to the current value and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_xor(2), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 5);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_xor</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">if</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicUsize</span><span class="op">></span>() {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">atomic::AtomicUsize</span>) };
<span class="ident">a</span>.<span class="ident">fetch_xor</span>(<span class="ident">val</span> <span class="kw">as</span> <span class="ident">usize</span>, <span class="ident">Ordering::AcqRel</span>) <span class="kw">as</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>
} <span class="kw">else</span> {
<span class="kw">let</span> <span class="ident">_guard</span> <span class="op">=</span> <span class="ident">lock</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="ident">usize</span>).<span class="ident">write</span>();
<span class="kw">let</span> <span class="ident">value</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>()) };
<span class="kw">let</span> <span class="ident">old</span> <span class="op">=</span> <span class="kw-2">*</span><span class="ident">value</span>;
<span class="kw-2">*</span><span class="ident">value</span> <span class="op">^</span><span class="op">=</span> <span class="ident">val</span>;
<span class="ident">old</span>
}
}
}
};
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">ty</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic</span>:<span class="ident">ty</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>:<span class="ident">tt</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">impl</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span><span class="op">></span> {
<span class="doccomment">/// Increments the current value by `val` and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The addition wraps on overflow.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_add(3), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 10);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_add</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic</span>) };
<span class="ident">a</span>.<span class="ident">fetch_add</span>(<span class="ident">val</span>, <span class="ident">Ordering::AcqRel</span>)
}
<span class="doccomment">/// Decrements the current value by `val` and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The subtraction wraps on overflow.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_sub(3), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 4);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_sub</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic</span>) };
<span class="ident">a</span>.<span class="ident">fetch_sub</span>(<span class="ident">val</span>, <span class="ident">Ordering::AcqRel</span>)
}
<span class="doccomment">/// Applies bitwise "and" to the current value and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_and(3), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 3);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_and</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic</span>) };
<span class="ident">a</span>.<span class="ident">fetch_and</span>(<span class="ident">val</span>, <span class="ident">Ordering::AcqRel</span>)
}
<span class="doccomment">/// Applies bitwise "or" to the current value and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_or(16), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 23);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_or</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic</span>) };
<span class="ident">a</span>.<span class="ident">fetch_or</span>(<span class="ident">val</span>, <span class="ident">Ordering::AcqRel</span>)
}
<span class="doccomment">/// Applies bitwise "xor" to the current value and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">doc</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">example</span>]</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_xor(2), 7);</span>
<span class="doccomment">/// assert_eq!(a.load(), 5);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_xor</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>) <span class="op">-</span><span class="op">></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic</span>) };
<span class="ident">a</span>.<span class="ident">fetch_xor</span>(<span class="ident">val</span>, <span class="ident">Ordering::AcqRel</span>)
}
}
};
}
<span class="macro">impl_arithmetic!</span>(<span class="ident">u8</span>, <span class="ident">atomic::AtomicU8</span>, <span class="string">"let a = AtomicCell::new(7u8);"</span>);
<span class="macro">impl_arithmetic!</span>(<span class="ident">i8</span>, <span class="ident">atomic::AtomicI8</span>, <span class="string">"let a = AtomicCell::new(7i8);"</span>);
<span class="macro">impl_arithmetic!</span>(<span class="ident">u16</span>, <span class="ident">atomic::AtomicU16</span>, <span class="string">"let a = AtomicCell::new(7u16);"</span>);
<span class="macro">impl_arithmetic!</span>(<span class="ident">i16</span>, <span class="ident">atomic::AtomicI16</span>, <span class="string">"let a = AtomicCell::new(7i16);"</span>);
<span class="macro">impl_arithmetic!</span>(<span class="ident">u32</span>, <span class="ident">atomic::AtomicU32</span>, <span class="string">"let a = AtomicCell::new(7u32);"</span>);
<span class="macro">impl_arithmetic!</span>(<span class="ident">i32</span>, <span class="ident">atomic::AtomicI32</span>, <span class="string">"let a = AtomicCell::new(7i32);"</span>);
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">crossbeam_no_atomic_64</span>))]</span>
<span class="macro">impl_arithmetic!</span>(<span class="ident">u64</span>, <span class="ident">atomic::AtomicU64</span>, <span class="string">"let a = AtomicCell::new(7u64);"</span>);
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">crossbeam_no_atomic_64</span>))]</span>
<span class="macro">impl_arithmetic!</span>(<span class="ident">i64</span>, <span class="ident">atomic::AtomicI64</span>, <span class="string">"let a = AtomicCell::new(7i64);"</span>);
<span class="comment">// TODO: AtomicU128 is unstable</span>
<span class="comment">// impl_arithmetic!(u128, atomic::AtomicU128, "let a = AtomicCell::new(7u128);");</span>
<span class="comment">// impl_arithmetic!(i128, atomic::AtomicI128, "let a = AtomicCell::new(7i128);");</span>
<span class="macro">impl_arithmetic!</span>(
<span class="ident">usize</span>,
<span class="ident">atomic::AtomicUsize</span>,
<span class="string">"let a = AtomicCell::new(7usize);"</span>
);
<span class="macro">impl_arithmetic!</span>(
<span class="ident">isize</span>,
<span class="ident">atomic::AtomicIsize</span>,
<span class="string">"let a = AtomicCell::new(7isize);"</span>
);
<span class="kw">impl</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">bool</span><span class="op">></span> {
<span class="doccomment">/// Applies logical "and" to the current value and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(true);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_and(true), true);</span>
<span class="doccomment">/// assert_eq!(a.load(), true);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_and(false), true);</span>
<span class="doccomment">/// assert_eq!(a.load(), false);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_and</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="ident">bool</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">AtomicBool</span>) };
<span class="ident">a</span>.<span class="ident">fetch_and</span>(<span class="ident">val</span>, <span class="ident">Ordering::AcqRel</span>)
}
<span class="doccomment">/// Applies logical "or" to the current value and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(false);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_or(false), false);</span>
<span class="doccomment">/// assert_eq!(a.load(), false);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_or(true), false);</span>
<span class="doccomment">/// assert_eq!(a.load(), true);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_or</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="ident">bool</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">AtomicBool</span>) };
<span class="ident">a</span>.<span class="ident">fetch_or</span>(<span class="ident">val</span>, <span class="ident">Ordering::AcqRel</span>)
}
<span class="doccomment">/// Applies logical "xor" to the current value and returns the previous value.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use crossbeam_utils::atomic::AtomicCell;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let a = AtomicCell::new(true);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_xor(false), true);</span>
<span class="doccomment">/// assert_eq!(a.load(), true);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(a.fetch_xor(true), true);</span>
<span class="doccomment">/// assert_eq!(a.load(), false);</span>
<span class="doccomment">/// ```</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fetch_xor</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">val</span>: <span class="ident">bool</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span>.<span class="ident">value</span>.<span class="ident">get</span>() <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">AtomicBool</span>) };
<span class="ident">a</span>.<span class="ident">fetch_xor</span>(<span class="ident">val</span>, <span class="ident">Ordering::AcqRel</span>)
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Default</span><span class="op">></span> <span class="ident">Default</span> <span class="kw">for</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">default</span>() <span class="op">-</span><span class="op">></span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">AtomicCell::new</span>(<span class="ident">T::default</span>())
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">From</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="kw">for</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">val</span>: <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">AtomicCell::new</span>(<span class="ident">val</span>)
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Copy</span> <span class="op">+</span> <span class="ident">fmt::Debug</span><span class="op">></span> <span class="ident">fmt::Debug</span> <span class="kw">for</span> <span class="ident">AtomicCell</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt::Formatter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt::Result</span> {
<span class="ident">f</span>.<span class="ident">debug_struct</span>(<span class="string">"AtomicCell"</span>)
.<span class="ident">field</span>(<span class="string">"value"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">load</span>())
.<span class="ident">finish</span>()
}
}
<span class="doccomment">/// Returns `true` if values of type `A` can be transmuted into values of type `B`.</span>
<span class="kw">const</span> <span class="kw">fn</span> <span class="ident">can_transmute</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span>() <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="comment">// Sizes must be equal, but alignment of `A` must be greater or equal than that of `B`.</span>
(<span class="ident">mem::size_of</span>::<span class="op"><</span><span class="ident">A</span><span class="op">></span>() <span class="op">=</span><span class="op">=</span> <span class="ident">mem::size_of</span>::<span class="op"><</span><span class="ident">B</span><span class="op">></span>()) <span class="op">&</span> (<span class="ident">mem::align_of</span>::<span class="op"><</span><span class="ident">A</span><span class="op">></span>() <span class="op">></span><span class="op">=</span> <span class="ident">mem::align_of</span>::<span class="op"><</span><span class="ident">B</span><span class="op">></span>())
}
<span class="doccomment">/// Returns a reference to the global lock associated with the `AtomicCell` at address `addr`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function is used to protect atomic data which doesn't fit into any of the primitive atomic</span>
<span class="doccomment">/// types in `std::sync::atomic`. Operations on such atomics must therefore use a global lock.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// However, there is not only one global lock but an array of many locks, and one of them is</span>
<span class="doccomment">/// picked based on the given address. Having many locks reduces contention and improves</span>
<span class="doccomment">/// scalability.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="attribute">#[<span class="ident">must_use</span>]</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">crossbeam_loom</span>))]</span>
<span class="kw">fn</span> <span class="ident">lock</span>(<span class="ident">addr</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">SeqLock</span> {
<span class="comment">// The number of locks is a prime number because we want to make sure `addr % LEN` gets</span>
<span class="comment">// dispersed across all locks.</span>
<span class="comment">//</span>
<span class="comment">// Note that addresses are always aligned to some power of 2, depending on type `T` in</span>
<span class="comment">// `AtomicCell<T>`. If `LEN` was an even number, then `addr % LEN` would be an even number,</span>
<span class="comment">// too, which means only half of the locks would get utilized!</span>
<span class="comment">//</span>
<span class="comment">// It is also possible for addresses to accidentally get aligned to a number that is not a</span>
<span class="comment">// power of 2. Consider this example:</span>
<span class="comment">//</span>
<span class="comment">// ```</span>
<span class="comment">// #[repr(C)]</span>
<span class="comment">// struct Foo {</span>
<span class="comment">// a: AtomicCell<u8>,</span>
<span class="comment">// b: u8,</span>
<span class="comment">// c: u8,</span>
<span class="comment">// }</span>
<span class="comment">// ```</span>
<span class="comment">//</span>
<span class="comment">// Now, if we have a slice of type `&[Foo]`, it is possible that field `a` in all items gets</span>
<span class="comment">// stored at addresses that are multiples of 3. It'd be too bad if `LEN` was divisible by 3.</span>
<span class="comment">// In order to protect from such cases, we simply choose a large prime number for `LEN`.</span>
<span class="kw">const</span> <span class="ident">LEN</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">97</span>;
<span class="kw">static</span> <span class="ident">LOCKS</span>: [<span class="ident">SeqLock</span>; <span class="ident">LEN</span>] <span class="op">=</span> [
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
<span class="ident">SeqLock::new</span>(),
];
<span class="comment">// If the modulus is a constant number, the compiler will use crazy math to transform this into</span>
<span class="comment">// a sequence of cheap arithmetic operations rather than using the slow modulo instruction.</span>
<span class="kw-2">&</span><span class="ident">LOCKS</span>[<span class="ident">addr</span> <span class="op">%</span> <span class="ident">LEN</span>]
}
<span class="doccomment">/// An atomic `()`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// All operations are noops.</span>
<span class="kw">struct</span> <span class="ident">AtomicUnit</span>;
<span class="kw">impl</span> <span class="ident">AtomicUnit</span> {
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">load</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">_order</span>: <span class="ident">Ordering</span>) {}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">store</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">_val</span>: (), <span class="ident">_order</span>: <span class="ident">Ordering</span>) {}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">swap</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">_val</span>: (), <span class="ident">_order</span>: <span class="ident">Ordering</span>) {}
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">clippy::unnecessary_wraps</span>)]</span> <span class="comment">// This is intentional.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">compare_exchange_weak</span>(
<span class="kw-2">&</span><span class="self">self</span>,
<span class="ident">_current</span>: (),
<span class="ident">_new</span>: (),
<span class="ident">_success</span>: <span class="ident">Ordering</span>,
<span class="ident">_failure</span>: <span class="ident">Ordering</span>,
) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span>(), ()<span class="op">></span> {
<span class="prelude-val">Ok</span>(())
}
}
<span class="macro">macro_rules!</span> <span class="ident">atomic</span> {
<span class="comment">// If values of type `$t` can be transmuted into values of the primitive atomic type `$atomic`,</span>
<span class="comment">// declares variable `$a` of type `$atomic` and executes `$atomic_op`, breaking out of the loop.</span>
(@<span class="ident">check</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">ty</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic</span>:<span class="ident">ty</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>:<span class="ident">ident</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic_op</span>:<span class="ident">expr</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">if</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic</span><span class="op">></span>() {
<span class="kw">let</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>: <span class="kw-2">&</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic</span>;
<span class="kw">break</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic_op</span>;
}
};
<span class="comment">// If values of type `$t` can be transmuted into values of a primitive atomic type, declares</span>
<span class="comment">// variable `$a` of that type and executes `$atomic_op`. Otherwise, just executes</span>
<span class="comment">// `$fallback_op`.</span>
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">ty</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>:<span class="ident">ident</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic_op</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">fallback_op</span>:<span class="ident">expr</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">loop</span> {
<span class="macro">atomic!</span>(@<span class="ident">check</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">AtomicUnit</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic_op</span>);
<span class="macro">atomic!</span>(@<span class="ident">check</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicUsize</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic_op</span>);
<span class="macro">atomic!</span>(@<span class="ident">check</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicU8</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic_op</span>);
<span class="macro">atomic!</span>(@<span class="ident">check</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicU16</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic_op</span>);
<span class="macro">atomic!</span>(@<span class="ident">check</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicU32</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic_op</span>);
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">crossbeam_no_atomic_64</span>))]</span>
<span class="macro">atomic!</span>(@<span class="ident">check</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>, <span class="ident">atomic::AtomicU64</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">a</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">atomic_op</span>);
<span class="comment">// TODO: AtomicU128 is unstable</span>
<span class="comment">// atomic!(@check, $t, atomic::AtomicU128, $a, $atomic_op);</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">crossbeam_loom</span>)]</span>
<span class="macro">unimplemented!</span>(<span class="string">"loom does not support non-atomic atomic ops"</span>);
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">crossbeam_loom</span>))]</span>
<span class="kw">break</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">fallback_op</span>;
}
};
}
<span class="doccomment">/// Returns `true` if operations on `AtomicCell<T>` are lock-free.</span>
<span class="kw">const</span> <span class="kw">fn</span> <span class="ident">atomic_is_lock_free</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>() <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="comment">// HACK(taiki-e): This is equivalent to `atomic! { T, _a, true, false }`, but can be used in const fn even in Rust 1.36.</span>
<span class="kw">let</span> <span class="ident">is_lock_free</span> <span class="op">=</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="ident">T</span>, <span class="ident">AtomicUnit</span><span class="op">></span>()
<span class="op">|</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="ident">T</span>, <span class="ident">atomic::AtomicUsize</span><span class="op">></span>()
<span class="op">|</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="ident">T</span>, <span class="ident">atomic::AtomicU8</span><span class="op">></span>()
<span class="op">|</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="ident">T</span>, <span class="ident">atomic::AtomicU16</span><span class="op">></span>()
<span class="op">|</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="ident">T</span>, <span class="ident">atomic::AtomicU32</span><span class="op">></span>();
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">crossbeam_no_atomic_64</span>))]</span>
<span class="kw">let</span> <span class="ident">is_lock_free</span> <span class="op">=</span> <span class="ident">is_lock_free</span> <span class="op">|</span> <span class="ident">can_transmute</span>::<span class="op"><</span><span class="ident">T</span>, <span class="ident">atomic::AtomicU64</span><span class="op">></span>();
<span class="comment">// TODO: AtomicU128 is unstable</span>
<span class="comment">// let is_lock_free = is_lock_free | can_transmute::<T, atomic::AtomicU128>();</span>
<span class="ident">is_lock_free</span>
}
<span class="doccomment">/// Atomically reads data from `src`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This operation uses the `Acquire` ordering. If possible, an atomic instructions is used, and a</span>
<span class="doccomment">/// global lock otherwise.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">atomic_load</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="ident">src</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="ident">T</span>
<span class="kw">where</span>
<span class="ident">T</span>: <span class="ident">Copy</span>,
{
<span class="macro">atomic!</span> {
<span class="ident">T</span>, <span class="ident">a</span>,
{
<span class="ident">a</span> <span class="op">=</span> <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="ident">src</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="kw">_</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="kw">_</span>);
<span class="ident">mem::transmute_copy</span>(<span class="kw-2">&</span><span class="ident">a</span>.<span class="ident">load</span>(<span class="ident">Ordering::Acquire</span>))
},
{
<span class="kw">let</span> <span class="ident">lock</span> <span class="op">=</span> <span class="ident">lock</span>(<span class="ident">src</span> <span class="kw">as</span> <span class="ident">usize</span>);
<span class="comment">// Try doing an optimistic read first.</span>
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">stamp</span>) <span class="op">=</span> <span class="ident">lock</span>.<span class="ident">optimistic_read</span>() {
<span class="comment">// We need a volatile read here because other threads might concurrently modify the</span>
<span class="comment">// value. In theory, data races are *always* UB, even if we use volatile reads and</span>
<span class="comment">// discard the data when a data race is detected. The proper solution would be to</span>
<span class="comment">// do atomic reads and atomic writes, but we can't atomically read and write all</span>
<span class="comment">// kinds of data since `AtomicU8` is not available on stable Rust yet.</span>
<span class="kw">let</span> <span class="ident">val</span> <span class="op">=</span> <span class="ident">ptr::read_volatile</span>(<span class="ident">src</span>);
<span class="kw">if</span> <span class="ident">lock</span>.<span class="ident">validate_read</span>(<span class="ident">stamp</span>) {
<span class="kw">return</span> <span class="ident">val</span>;
}
}
<span class="comment">// Grab a regular write lock so that writers don't starve this load.</span>
<span class="kw">let</span> <span class="ident">guard</span> <span class="op">=</span> <span class="ident">lock</span>.<span class="ident">write</span>();
<span class="kw">let</span> <span class="ident">val</span> <span class="op">=</span> <span class="ident">ptr::read</span>(<span class="ident">src</span>);
<span class="comment">// The value hasn't been changed. Drop the guard without incrementing the stamp.</span>
<span class="ident">guard</span>.<span class="ident">abort</span>();
<span class="ident">val</span>
}
}
}
<span class="doccomment">/// Atomically writes `val` to `dst`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This operation uses the `Release` ordering. If possible, an atomic instructions is used, and a</span>
<span class="doccomment">/// global lock otherwise.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">atomic_store</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="ident">dst</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">T</span>, <span class="ident">val</span>: <span class="ident">T</span>) {
<span class="macro">atomic!</span> {
<span class="ident">T</span>, <span class="ident">a</span>,
{
<span class="ident">a</span> <span class="op">=</span> <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="ident">dst</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="kw">_</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="kw">_</span>);
<span class="ident">a</span>.<span class="ident">store</span>(<span class="ident">mem::transmute_copy</span>(<span class="kw-2">&</span><span class="ident">val</span>), <span class="ident">Ordering::Release</span>);
<span class="ident">mem::forget</span>(<span class="ident">val</span>);
},
{
<span class="kw">let</span> <span class="ident">_guard</span> <span class="op">=</span> <span class="ident">lock</span>(<span class="ident">dst</span> <span class="kw">as</span> <span class="ident">usize</span>).<span class="ident">write</span>();
<span class="ident">ptr::write</span>(<span class="ident">dst</span>, <span class="ident">val</span>);
}
}
}
<span class="doccomment">/// Atomically swaps data at `dst` with `val`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This operation uses the `AcqRel` ordering. If possible, an atomic instructions is used, and a</span>
<span class="doccomment">/// global lock otherwise.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">atomic_swap</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="ident">dst</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">T</span>, <span class="ident">val</span>: <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="ident">T</span> {
<span class="macro">atomic!</span> {
<span class="ident">T</span>, <span class="ident">a</span>,
{
<span class="ident">a</span> <span class="op">=</span> <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="ident">dst</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="kw">_</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="kw">_</span>);
<span class="kw">let</span> <span class="ident">res</span> <span class="op">=</span> <span class="ident">mem::transmute_copy</span>(<span class="kw-2">&</span><span class="ident">a</span>.<span class="ident">swap</span>(<span class="ident">mem::transmute_copy</span>(<span class="kw-2">&</span><span class="ident">val</span>), <span class="ident">Ordering::AcqRel</span>));
<span class="ident">mem::forget</span>(<span class="ident">val</span>);
<span class="ident">res</span>
},
{
<span class="kw">let</span> <span class="ident">_guard</span> <span class="op">=</span> <span class="ident">lock</span>(<span class="ident">dst</span> <span class="kw">as</span> <span class="ident">usize</span>).<span class="ident">write</span>();
<span class="ident">ptr::replace</span>(<span class="ident">dst</span>, <span class="ident">val</span>)
}
}
}
<span class="doccomment">/// Atomically compares data at `dst` to `current` and, if equal byte-for-byte, exchanges data at</span>
<span class="doccomment">/// `dst` with `new`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Returns the old value on success, or the current value at `dst` on failure.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This operation uses the `AcqRel` ordering. If possible, an atomic instructions is used, and a</span>
<span class="doccomment">/// global lock otherwise.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">atomic_compare_exchange_weak</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="ident">dst</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">T</span>, <span class="kw-2">mut</span> <span class="ident">current</span>: <span class="ident">T</span>, <span class="ident">new</span>: <span class="ident">T</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span>, <span class="ident">T</span><span class="op">></span>
<span class="kw">where</span>
<span class="ident">T</span>: <span class="ident">Copy</span> <span class="op">+</span> <span class="ident">Eq</span>,
{
<span class="macro">atomic!</span> {
<span class="ident">T</span>, <span class="ident">a</span>,
{
<span class="ident">a</span> <span class="op">=</span> <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="ident">dst</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="kw">_</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="kw">_</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">current_raw</span> <span class="op">=</span> <span class="ident">mem::transmute_copy</span>(<span class="kw-2">&</span><span class="ident">current</span>);
<span class="kw">let</span> <span class="ident">new_raw</span> <span class="op">=</span> <span class="ident">mem::transmute_copy</span>(<span class="kw-2">&</span><span class="ident">new</span>);
<span class="kw">loop</span> {
<span class="kw">match</span> <span class="ident">a</span>.<span class="ident">compare_exchange_weak</span>(
<span class="ident">current_raw</span>,
<span class="ident">new_raw</span>,
<span class="ident">Ordering::AcqRel</span>,
<span class="ident">Ordering::Acquire</span>,
) {
<span class="prelude-val">Ok</span>(<span class="kw">_</span>) <span class="op">=</span><span class="op">></span> <span class="kw">break</span> <span class="prelude-val">Ok</span>(<span class="ident">current</span>),
<span class="prelude-val">Err</span>(<span class="ident">previous_raw</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">previous</span> <span class="op">=</span> <span class="ident">mem::transmute_copy</span>(<span class="kw-2">&</span><span class="ident">previous_raw</span>);
<span class="kw">if</span> <span class="op">!</span><span class="ident">T::eq</span>(<span class="kw-2">&</span><span class="ident">previous</span>, <span class="kw-2">&</span><span class="ident">current</span>) {
<span class="kw">break</span> <span class="prelude-val">Err</span>(<span class="ident">previous</span>);
}
<span class="comment">// The compare-exchange operation has failed and didn't store `new`. The</span>
<span class="comment">// failure is either spurious, or `previous` was semantically equal to</span>
<span class="comment">// `current` but not byte-equal. Let's retry with `previous` as the new</span>
<span class="comment">// `current`.</span>
<span class="ident">current</span> <span class="op">=</span> <span class="ident">previous</span>;
<span class="ident">current_raw</span> <span class="op">=</span> <span class="ident">previous_raw</span>;
}
}
}
},
{
<span class="kw">let</span> <span class="ident">guard</span> <span class="op">=</span> <span class="ident">lock</span>(<span class="ident">dst</span> <span class="kw">as</span> <span class="ident">usize</span>).<span class="ident">write</span>();
<span class="kw">if</span> <span class="ident">T::eq</span>(<span class="kw-2">&</span><span class="kw-2">*</span><span class="ident">dst</span>, <span class="kw-2">&</span><span class="ident">current</span>) {
<span class="prelude-val">Ok</span>(<span class="ident">ptr::replace</span>(<span class="ident">dst</span>, <span class="ident">new</span>))
} <span class="kw">else</span> {
<span class="kw">let</span> <span class="ident">val</span> <span class="op">=</span> <span class="ident">ptr::read</span>(<span class="ident">dst</span>);
<span class="comment">// The value hasn't been changed. Drop the guard without incrementing the stamp.</span>
<span class="ident">guard</span>.<span class="ident">abort</span>();
<span class="prelude-val">Err</span>(<span class="ident">val</span>)
}
}
}
}
</pre></div>
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