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</pre><pre class="rust">
<span class="doccomment">//! Methods for custom fork-join scopes, created by the [`scope()`]</span>
<span class="doccomment">//! and [`in_place_scope()`] functions. These are a more flexible alternative to [`join()`].</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! [`scope()`]: fn.scope.html</span>
<span class="doccomment">//! [`in_place_scope()`]: fn.in_place_scope.html</span>
<span class="doccomment">//! [`join()`]: ../join/join.fn.html</span>
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::job</span>::{<span class="ident">HeapJob</span>, <span class="ident">JobFifo</span>};
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::latch</span>::{<span class="ident">CountLatch</span>, <span class="ident">CountLockLatch</span>, <span class="ident">Latch</span>};
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::registry</span>::{<span class="ident">global_registry</span>, <span class="ident">in_worker</span>, <span class="ident">Registry</span>, <span class="ident">WorkerThread</span>};
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::unwind</span>;
<span class="kw">use</span> <span class="ident">std::any::Any</span>;
<span class="kw">use</span> <span class="ident">std::fmt</span>;
<span class="kw">use</span> <span class="ident">std::marker::PhantomData</span>;
<span class="kw">use</span> <span class="ident">std::mem</span>;
<span class="kw">use</span> <span class="ident">std::ptr</span>;
<span class="kw">use</span> <span class="ident">std::sync::atomic</span>::{<span class="ident">AtomicPtr</span>, <span class="ident">Ordering</span>};
<span class="kw">use</span> <span class="ident">std::sync::Arc</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span>
<span class="kw">mod</span> <span class="ident">test</span>;
<span class="doccomment">/// Represents a fork-join scope which can be used to spawn any number of tasks.</span>
<span class="doccomment">/// See [`scope()`] for more information.</span>
<span class="doccomment">///</span>
<span class="doccomment">///[`scope()`]: fn.scope.html</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Scope</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> {
<span class="ident">base</span>: <span class="ident">ScopeBase</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>,
}
<span class="doccomment">/// Represents a fork-join scope which can be used to spawn any number of tasks.</span>
<span class="doccomment">/// Those spawned from the same thread are prioritized in relative FIFO order.</span>
<span class="doccomment">/// See [`scope_fifo()`] for more information.</span>
<span class="doccomment">///</span>
<span class="doccomment">///[`scope_fifo()`]: fn.scope_fifo.html</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ScopeFifo</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> {
<span class="ident">base</span>: <span class="ident">ScopeBase</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>,
<span class="ident">fifos</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">JobFifo</span><span class="op">></span>,
}
<span class="kw">enum</span> <span class="ident">ScopeLatch</span> {
<span class="doccomment">/// A latch for scopes created on a rayon thread which will participate in work-</span>
<span class="doccomment">/// stealing while it waits for completion. This thread is not necessarily part</span>
<span class="doccomment">/// of the same registry as the scope itself!</span>
<span class="ident">Stealing</span> {
<span class="ident">latch</span>: <span class="ident">CountLatch</span>,
<span class="doccomment">/// If a worker thread in registry A calls `in_place_scope` on a ThreadPool</span>
<span class="doccomment">/// with registry B, when a job completes in a thread of registry B, we may</span>
<span class="doccomment">/// need to call `latch.set_and_tickle_one()` to wake the thread in registry A.</span>
<span class="doccomment">/// That means we need a reference to registry A (since at that point we will</span>
<span class="doccomment">/// only have a reference to registry B), so we stash it here.</span>
<span class="ident">registry</span>: <span class="ident">Arc</span><span class="op"><</span><span class="ident">Registry</span><span class="op">></span>,
<span class="doccomment">/// The index of the worker to wake in `registry`</span>
<span class="ident">worker_index</span>: <span class="ident">usize</span>,
},
<span class="doccomment">/// A latch for scopes created on a non-rayon thread which will block to wait.</span>
<span class="ident">Blocking</span> { <span class="ident">latch</span>: <span class="ident">CountLockLatch</span> },
}
<span class="kw">struct</span> <span class="ident">ScopeBase</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> {
<span class="doccomment">/// thread registry where `scope()` was executed or where `in_place_scope()`</span>
<span class="doccomment">/// should spawn jobs.</span>
<span class="ident">registry</span>: <span class="ident">Arc</span><span class="op"><</span><span class="ident">Registry</span><span class="op">></span>,
<span class="doccomment">/// if some job panicked, the error is stored here; it will be</span>
<span class="doccomment">/// propagated to the one who created the scope</span>
<span class="ident">panic</span>: <span class="ident">AtomicPtr</span><span class="op"><</span><span class="ident">Box</span><span class="op"><</span><span class="kw">dyn</span> <span class="ident">Any</span> <span class="op">+</span> <span class="ident">Send</span> <span class="op">+</span> <span class="lifetime">'static</span><span class="op">></span><span class="op">></span>,
<span class="doccomment">/// latch to track job counts</span>
<span class="ident">job_completed_latch</span>: <span class="ident">ScopeLatch</span>,
<span class="doccomment">/// You can think of a scope as containing a list of closures to execute,</span>
<span class="doccomment">/// all of which outlive `'scope`. They're not actually required to be</span>
<span class="doccomment">/// `Sync`, but it's still safe to let the `Scope` implement `Sync` because</span>
<span class="doccomment">/// the closures are only *moved* across threads to be executed.</span>
<span class="ident">marker</span>: <span class="ident">PhantomData</span><span class="op"><</span><span class="ident">Box</span><span class="op"><</span><span class="kw">dyn</span> <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">Scope</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>) <span class="op">+</span> <span class="ident">Send</span> <span class="op">+</span> <span class="ident">Sync</span> <span class="op">+</span> <span class="lifetime">'scope</span><span class="op">></span><span class="op">></span>,
}
<span class="doccomment">/// Creates a "fork-join" scope `s` and invokes the closure with a</span>
<span class="doccomment">/// reference to `s`. This closure can then spawn asynchronous tasks</span>
<span class="doccomment">/// into `s`. Those tasks may run asynchronously with respect to the</span>
<span class="doccomment">/// closure; they may themselves spawn additional tasks into `s`. When</span>
<span class="doccomment">/// the closure returns, it will block until all tasks that have been</span>
<span class="doccomment">/// spawned into `s` complete.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// `scope()` is a more flexible building block compared to `join()`,</span>
<span class="doccomment">/// since a loop can be used to spawn any number of tasks without</span>
<span class="doccomment">/// recursing. However, that flexibility comes at a performance price:</span>
<span class="doccomment">/// tasks spawned using `scope()` must be allocated onto the heap,</span>
<span class="doccomment">/// whereas `join()` can make exclusive use of the stack. **Prefer</span>
<span class="doccomment">/// `join()` (or, even better, parallel iterators) where possible.**</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Example</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The Rayon `join()` function launches two closures and waits for them</span>
<span class="doccomment">/// to stop. One could implement `join()` using a scope like so, although</span>
<span class="doccomment">/// it would be less efficient than the real implementation:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// # use rayon_core as rayon;</span>
<span class="doccomment">/// pub fn join<A,B,RA,RB>(oper_a: A, oper_b: B) -> (RA, RB)</span>
<span class="doccomment">/// where A: FnOnce() -> RA + Send,</span>
<span class="doccomment">/// B: FnOnce() -> RB + Send,</span>
<span class="doccomment">/// RA: Send,</span>
<span class="doccomment">/// RB: Send,</span>
<span class="doccomment">/// {</span>
<span class="doccomment">/// let mut result_a: Option<RA> = None;</span>
<span class="doccomment">/// let mut result_b: Option<RB> = None;</span>
<span class="doccomment">/// rayon::scope(|s| {</span>
<span class="doccomment">/// s.spawn(|_| result_a = Some(oper_a()));</span>
<span class="doccomment">/// s.spawn(|_| result_b = Some(oper_b()));</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// (result_a.unwrap(), result_b.unwrap())</span>
<span class="doccomment">/// }</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # A note on threading</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The closure given to `scope()` executes in the Rayon thread-pool,</span>
<span class="doccomment">/// as do those given to `spawn()`. This means that you can't access</span>
<span class="doccomment">/// thread-local variables (well, you can, but they may have</span>
<span class="doccomment">/// unexpected values).</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Task execution</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Task execution potentially starts as soon as `spawn()` is called.</span>
<span class="doccomment">/// The task will end sometime before `scope()` returns. Note that the</span>
<span class="doccomment">/// *closure* given to scope may return much earlier. In general</span>
<span class="doccomment">/// the lifetime of a scope created like `scope(body) goes something like this:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// - Scope begins when `scope(body)` is called</span>
<span class="doccomment">/// - Scope body `body()` is invoked</span>
<span class="doccomment">/// - Scope tasks may be spawned</span>
<span class="doccomment">/// - Scope body returns</span>
<span class="doccomment">/// - Scope tasks execute, possibly spawning more tasks</span>
<span class="doccomment">/// - Once all tasks are done, scope ends and `scope()` returns</span>
<span class="doccomment">///</span>
<span class="doccomment">/// To see how and when tasks are joined, consider this example:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// # use rayon_core as rayon;</span>
<span class="doccomment">/// // point start</span>
<span class="doccomment">/// rayon::scope(|s| {</span>
<span class="doccomment">/// s.spawn(|s| { // task s.1</span>
<span class="doccomment">/// s.spawn(|s| { // task s.1.1</span>
<span class="doccomment">/// rayon::scope(|t| {</span>
<span class="doccomment">/// t.spawn(|_| ()); // task t.1</span>
<span class="doccomment">/// t.spawn(|_| ()); // task t.2</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// s.spawn(|s| { // task s.2</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// // point mid</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// // point end</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The various tasks that are run will execute roughly like so:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```notrust</span>
<span class="doccomment">/// | (start)</span>
<span class="doccomment">/// |</span>
<span class="doccomment">/// | (scope `s` created)</span>
<span class="doccomment">/// +-----------------------------------------------+ (task s.2)</span>
<span class="doccomment">/// +-------+ (task s.1) |</span>
<span class="doccomment">/// | | |</span>
<span class="doccomment">/// | +---+ (task s.1.1) |</span>
<span class="doccomment">/// | | | |</span>
<span class="doccomment">/// | | | (scope `t` created) |</span>
<span class="doccomment">/// | | +----------------+ (task t.2) |</span>
<span class="doccomment">/// | | +---+ (task t.1) | |</span>
<span class="doccomment">/// | (mid) | | | | |</span>
<span class="doccomment">/// : | + <-+------------+ (scope `t` ends) |</span>
<span class="doccomment">/// : | | |</span>
<span class="doccomment">/// |<------+---+-----------------------------------+ (scope `s` ends)</span>
<span class="doccomment">/// |</span>
<span class="doccomment">/// | (end)</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The point here is that everything spawned into scope `s` will</span>
<span class="doccomment">/// terminate (at latest) at the same point -- right before the</span>
<span class="doccomment">/// original call to `rayon::scope` returns. This includes new</span>
<span class="doccomment">/// subtasks created by other subtasks (e.g., task `s.1.1`). If a new</span>
<span class="doccomment">/// scope is created (such as `t`), the things spawned into that scope</span>
<span class="doccomment">/// will be joined before that scope returns, which in turn occurs</span>
<span class="doccomment">/// before the creating task (task `s.1.1` in this case) finishes.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// There is no guaranteed order of execution for spawns in a scope,</span>
<span class="doccomment">/// given that other threads may steal tasks at any time. However, they</span>
<span class="doccomment">/// are generally prioritized in a LIFO order on the thread from which</span>
<span class="doccomment">/// they were spawned. So in this example, absent any stealing, we can</span>
<span class="doccomment">/// expect `s.2` to execute before `s.1`, and `t.2` before `t.1`. Other</span>
<span class="doccomment">/// threads always steal from the other end of the deque, like FIFO</span>
<span class="doccomment">/// order. The idea is that "recent" tasks are most likely to be fresh</span>
<span class="doccomment">/// in the local CPU's cache, while other threads can steal older</span>
<span class="doccomment">/// "stale" tasks. For an alternate approach, consider</span>
<span class="doccomment">/// [`scope_fifo()`] instead.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`scope_fifo()`]: fn.scope_fifo.html</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Accessing stack data</span>
<span class="doccomment">///</span>
<span class="doccomment">/// In general, spawned tasks may access stack data in place that</span>
<span class="doccomment">/// outlives the scope itself. Other data must be fully owned by the</span>
<span class="doccomment">/// spawned task.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// # use rayon_core as rayon;</span>
<span class="doccomment">/// let ok: Vec<i32> = vec![1, 2, 3];</span>
<span class="doccomment">/// rayon::scope(|s| {</span>
<span class="doccomment">/// let bad: Vec<i32> = vec![4, 5, 6];</span>
<span class="doccomment">/// s.spawn(|_| {</span>
<span class="doccomment">/// // We can access `ok` because outlives the scope `s`.</span>
<span class="doccomment">/// println!("ok: {:?}", ok);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // If we just try to use `bad` here, the closure will borrow `bad`</span>
<span class="doccomment">/// // (because we are just printing it out, and that only requires a</span>
<span class="doccomment">/// // borrow), which will result in a compilation error. Read on</span>
<span class="doccomment">/// // for options.</span>
<span class="doccomment">/// // println!("bad: {:?}", bad);</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// As the comments example above suggest, to reference `bad` we must</span>
<span class="doccomment">/// take ownership of it. One way to do this is to detach the closure</span>
<span class="doccomment">/// from the surrounding stack frame, using the `move` keyword. This</span>
<span class="doccomment">/// will cause it to take ownership of *all* the variables it touches,</span>
<span class="doccomment">/// in this case including both `ok` *and* `bad`:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// # use rayon_core as rayon;</span>
<span class="doccomment">/// let ok: Vec<i32> = vec![1, 2, 3];</span>
<span class="doccomment">/// rayon::scope(|s| {</span>
<span class="doccomment">/// let bad: Vec<i32> = vec![4, 5, 6];</span>
<span class="doccomment">/// s.spawn(move |_| {</span>
<span class="doccomment">/// println!("ok: {:?}", ok);</span>
<span class="doccomment">/// println!("bad: {:?}", bad);</span>
<span class="doccomment">/// });</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // That closure is fine, but now we can't use `ok` anywhere else,</span>
<span class="doccomment">/// // since it is owend by the previous task:</span>
<span class="doccomment">/// // s.spawn(|_| println!("ok: {:?}", ok));</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// While this works, it could be a problem if we want to use `ok` elsewhere.</span>
<span class="doccomment">/// There are two choices. We can keep the closure as a `move` closure, but</span>
<span class="doccomment">/// instead of referencing the variable `ok`, we create a shadowed variable that</span>
<span class="doccomment">/// is a borrow of `ok` and capture *that*:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// # use rayon_core as rayon;</span>
<span class="doccomment">/// let ok: Vec<i32> = vec![1, 2, 3];</span>
<span class="doccomment">/// rayon::scope(|s| {</span>
<span class="doccomment">/// let bad: Vec<i32> = vec![4, 5, 6];</span>
<span class="doccomment">/// let ok: &Vec<i32> = &ok; // shadow the original `ok`</span>
<span class="doccomment">/// s.spawn(move |_| {</span>
<span class="doccomment">/// println!("ok: {:?}", ok); // captures the shadowed version</span>
<span class="doccomment">/// println!("bad: {:?}", bad);</span>
<span class="doccomment">/// });</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // Now we too can use the shadowed `ok`, since `&Vec<i32>` references</span>
<span class="doccomment">/// // can be shared freely. Note that we need a `move` closure here though,</span>
<span class="doccomment">/// // because otherwise we'd be trying to borrow the shadowed `ok`,</span>
<span class="doccomment">/// // and that doesn't outlive `scope`.</span>
<span class="doccomment">/// s.spawn(move |_| println!("ok: {:?}", ok));</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Another option is not to use the `move` keyword but instead to take ownership</span>
<span class="doccomment">/// of individual variables:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// # use rayon_core as rayon;</span>
<span class="doccomment">/// let ok: Vec<i32> = vec![1, 2, 3];</span>
<span class="doccomment">/// rayon::scope(|s| {</span>
<span class="doccomment">/// let bad: Vec<i32> = vec![4, 5, 6];</span>
<span class="doccomment">/// s.spawn(|_| {</span>
<span class="doccomment">/// // Transfer ownership of `bad` into a local variable (also named `bad`).</span>
<span class="doccomment">/// // This will force the closure to take ownership of `bad` from the environment.</span>
<span class="doccomment">/// let bad = bad;</span>
<span class="doccomment">/// println!("ok: {:?}", ok); // `ok` is only borrowed.</span>
<span class="doccomment">/// println!("bad: {:?}", bad); // refers to our local variable, above.</span>
<span class="doccomment">/// });</span>
<span class="doccomment">///</span>
<span class="doccomment">/// s.spawn(|_| println!("ok: {:?}", ok)); // we too can borrow `ok`</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Panics</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If a panic occurs, either in the closure given to `scope()` or in</span>
<span class="doccomment">/// any of the spawned jobs, that panic will be propagated and the</span>
<span class="doccomment">/// call to `scope()` will panic. If multiple panics occurs, it is</span>
<span class="doccomment">/// non-deterministic which of their panic values will propagate.</span>
<span class="doccomment">/// Regardless, once a task is spawned using `scope.spawn()`, it will</span>
<span class="doccomment">/// execute, even if the spawning task should later panic. `scope()`</span>
<span class="doccomment">/// returns once all spawned jobs have completed, and any panics are</span>
<span class="doccomment">/// propagated at that point.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">scope</span><span class="op"><</span><span class="lifetime">'scope</span>, <span class="ident">OP</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">op</span>: <span class="ident">OP</span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>
<span class="kw">where</span>
<span class="ident">OP</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">Scope</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span> <span class="op">+</span> <span class="ident">Send</span>,
<span class="ident">R</span>: <span class="ident">Send</span>,
{
<span class="ident">in_worker</span>(<span class="op">|</span><span class="ident">owner_thread</span>, <span class="kw">_</span><span class="op">|</span> {
<span class="kw">let</span> <span class="ident">scope</span> <span class="op">=</span> <span class="ident">Scope</span>::<span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span><span class="ident">::new</span>(<span class="prelude-val">Some</span>(<span class="ident">owner_thread</span>), <span class="prelude-val">None</span>);
<span class="ident">scope</span>.<span class="ident">base</span>.<span class="ident">complete</span>(<span class="prelude-val">Some</span>(<span class="ident">owner_thread</span>), <span class="op">|</span><span class="op">|</span> <span class="ident">op</span>(<span class="kw-2">&</span><span class="ident">scope</span>))
})
}
<span class="doccomment">/// Creates a "fork-join" scope `s` with FIFO order, and invokes the</span>
<span class="doccomment">/// closure with a reference to `s`. This closure can then spawn</span>
<span class="doccomment">/// asynchronous tasks into `s`. Those tasks may run asynchronously with</span>
<span class="doccomment">/// respect to the closure; they may themselves spawn additional tasks</span>
<span class="doccomment">/// into `s`. When the closure returns, it will block until all tasks</span>
<span class="doccomment">/// that have been spawned into `s` complete.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Task execution</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Tasks in a `scope_fifo()` run similarly to [`scope()`], but there's a</span>
<span class="doccomment">/// difference in the order of execution. Consider a similar example:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`scope()`]: fn.scope.html</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// # use rayon_core as rayon;</span>
<span class="doccomment">/// // point start</span>
<span class="doccomment">/// rayon::scope_fifo(|s| {</span>
<span class="doccomment">/// s.spawn_fifo(|s| { // task s.1</span>
<span class="doccomment">/// s.spawn_fifo(|s| { // task s.1.1</span>
<span class="doccomment">/// rayon::scope_fifo(|t| {</span>
<span class="doccomment">/// t.spawn_fifo(|_| ()); // task t.1</span>
<span class="doccomment">/// t.spawn_fifo(|_| ()); // task t.2</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// s.spawn_fifo(|s| { // task s.2</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// // point mid</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// // point end</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The various tasks that are run will execute roughly like so:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```notrust</span>
<span class="doccomment">/// | (start)</span>
<span class="doccomment">/// |</span>
<span class="doccomment">/// | (FIFO scope `s` created)</span>
<span class="doccomment">/// +--------------------+ (task s.1)</span>
<span class="doccomment">/// +-------+ (task s.2) |</span>
<span class="doccomment">/// | | +---+ (task s.1.1)</span>
<span class="doccomment">/// | | | |</span>
<span class="doccomment">/// | | | | (FIFO scope `t` created)</span>
<span class="doccomment">/// | | | +----------------+ (task t.1)</span>
<span class="doccomment">/// | | | +---+ (task t.2) |</span>
<span class="doccomment">/// | (mid) | | | | |</span>
<span class="doccomment">/// : | | + <-+------------+ (scope `t` ends)</span>
<span class="doccomment">/// : | | |</span>
<span class="doccomment">/// |<------+------------+---+ (scope `s` ends)</span>
<span class="doccomment">/// |</span>
<span class="doccomment">/// | (end)</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Under `scope_fifo()`, the spawns are prioritized in a FIFO order on</span>
<span class="doccomment">/// the thread from which they were spawned, as opposed to `scope()`'s</span>
<span class="doccomment">/// LIFO. So in this example, we can expect `s.1` to execute before</span>
<span class="doccomment">/// `s.2`, and `t.1` before `t.2`. Other threads also steal tasks in</span>
<span class="doccomment">/// FIFO order, as usual. Overall, this has roughly the same order as</span>
<span class="doccomment">/// the now-deprecated [`breadth_first`] option, except the effect is</span>
<span class="doccomment">/// isolated to a particular scope. If spawns are intermingled from any</span>
<span class="doccomment">/// combination of `scope()` and `scope_fifo()`, or from different</span>
<span class="doccomment">/// threads, their order is only specified with respect to spawns in the</span>
<span class="doccomment">/// same scope and thread.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// For more details on this design, see Rayon [RFC #1].</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`breadth_first`]: struct.ThreadPoolBuilder.html#method.breadth_first</span>
<span class="doccomment">/// [RFC #1]: https://github.com/rayon-rs/rfcs/blob/master/accepted/rfc0001-scope-scheduling.md</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Panics</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If a panic occurs, either in the closure given to `scope_fifo()` or</span>
<span class="doccomment">/// in any of the spawned jobs, that panic will be propagated and the</span>
<span class="doccomment">/// call to `scope_fifo()` will panic. If multiple panics occurs, it is</span>
<span class="doccomment">/// non-deterministic which of their panic values will propagate.</span>
<span class="doccomment">/// Regardless, once a task is spawned using `scope.spawn_fifo()`, it</span>
<span class="doccomment">/// will execute, even if the spawning task should later panic.</span>
<span class="doccomment">/// `scope_fifo()` returns once all spawned jobs have completed, and any</span>
<span class="doccomment">/// panics are propagated at that point.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">scope_fifo</span><span class="op"><</span><span class="lifetime">'scope</span>, <span class="ident">OP</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">op</span>: <span class="ident">OP</span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>
<span class="kw">where</span>
<span class="ident">OP</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">ScopeFifo</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span> <span class="op">+</span> <span class="ident">Send</span>,
<span class="ident">R</span>: <span class="ident">Send</span>,
{
<span class="ident">in_worker</span>(<span class="op">|</span><span class="ident">owner_thread</span>, <span class="kw">_</span><span class="op">|</span> {
<span class="kw">let</span> <span class="ident">scope</span> <span class="op">=</span> <span class="ident">ScopeFifo</span>::<span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span><span class="ident">::new</span>(<span class="prelude-val">Some</span>(<span class="ident">owner_thread</span>), <span class="prelude-val">None</span>);
<span class="ident">scope</span>.<span class="ident">base</span>.<span class="ident">complete</span>(<span class="prelude-val">Some</span>(<span class="ident">owner_thread</span>), <span class="op">|</span><span class="op">|</span> <span class="ident">op</span>(<span class="kw-2">&</span><span class="ident">scope</span>))
})
}
<span class="doccomment">/// Creates a "fork-join" scope `s` and invokes the closure with a</span>
<span class="doccomment">/// reference to `s`. This closure can then spawn asynchronous tasks</span>
<span class="doccomment">/// into `s`. Those tasks may run asynchronously with respect to the</span>
<span class="doccomment">/// closure; they may themselves spawn additional tasks into `s`. When</span>
<span class="doccomment">/// the closure returns, it will block until all tasks that have been</span>
<span class="doccomment">/// spawned into `s` complete.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is just like `scope()` except the closure runs on the same thread</span>
<span class="doccomment">/// that calls `in_place_scope()`. Only work that it spawns runs in the</span>
<span class="doccomment">/// thread pool.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Panics</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If a panic occurs, either in the closure given to `in_place_scope()` or in</span>
<span class="doccomment">/// any of the spawned jobs, that panic will be propagated and the</span>
<span class="doccomment">/// call to `in_place_scope()` will panic. If multiple panics occurs, it is</span>
<span class="doccomment">/// non-deterministic which of their panic values will propagate.</span>
<span class="doccomment">/// Regardless, once a task is spawned using `scope.spawn()`, it will</span>
<span class="doccomment">/// execute, even if the spawning task should later panic. `in_place_scope()`</span>
<span class="doccomment">/// returns once all spawned jobs have completed, and any panics are</span>
<span class="doccomment">/// propagated at that point.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">in_place_scope</span><span class="op"><</span><span class="lifetime">'scope</span>, <span class="ident">OP</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">op</span>: <span class="ident">OP</span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>
<span class="kw">where</span>
<span class="ident">OP</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">Scope</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>,
{
<span class="ident">do_in_place_scope</span>(<span class="prelude-val">None</span>, <span class="ident">op</span>)
}
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">do_in_place_scope</span><span class="op"><</span><span class="lifetime">'scope</span>, <span class="ident">OP</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">registry</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">Arc</span><span class="op"><</span><span class="ident">Registry</span><span class="op">></span><span class="op">></span>, <span class="ident">op</span>: <span class="ident">OP</span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>
<span class="kw">where</span>
<span class="ident">OP</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">Scope</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>,
{
<span class="kw">let</span> <span class="ident">thread</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">WorkerThread::current</span>().<span class="ident">as_ref</span>() };
<span class="kw">let</span> <span class="ident">scope</span> <span class="op">=</span> <span class="ident">Scope</span>::<span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span><span class="ident">::new</span>(<span class="ident">thread</span>, <span class="ident">registry</span>);
<span class="ident">scope</span>.<span class="ident">base</span>.<span class="ident">complete</span>(<span class="ident">thread</span>, <span class="op">|</span><span class="op">|</span> <span class="ident">op</span>(<span class="kw-2">&</span><span class="ident">scope</span>))
}
<span class="doccomment">/// Creates a "fork-join" scope `s` with FIFO order, and invokes the</span>
<span class="doccomment">/// closure with a reference to `s`. This closure can then spawn</span>
<span class="doccomment">/// asynchronous tasks into `s`. Those tasks may run asynchronously with</span>
<span class="doccomment">/// respect to the closure; they may themselves spawn additional tasks</span>
<span class="doccomment">/// into `s`. When the closure returns, it will block until all tasks</span>
<span class="doccomment">/// that have been spawned into `s` complete.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is just like `scope_fifo()` except the closure runs on the same thread</span>
<span class="doccomment">/// that calls `in_place_scope_fifo()`. Only work that it spawns runs in the</span>
<span class="doccomment">/// thread pool.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Panics</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If a panic occurs, either in the closure given to `in_place_scope_fifo()` or in</span>
<span class="doccomment">/// any of the spawned jobs, that panic will be propagated and the</span>
<span class="doccomment">/// call to `in_place_scope_fifo()` will panic. If multiple panics occurs, it is</span>
<span class="doccomment">/// non-deterministic which of their panic values will propagate.</span>
<span class="doccomment">/// Regardless, once a task is spawned using `scope.spawn_fifo()`, it will</span>
<span class="doccomment">/// execute, even if the spawning task should later panic. `in_place_scope_fifo()`</span>
<span class="doccomment">/// returns once all spawned jobs have completed, and any panics are</span>
<span class="doccomment">/// propagated at that point.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">in_place_scope_fifo</span><span class="op"><</span><span class="lifetime">'scope</span>, <span class="ident">OP</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">op</span>: <span class="ident">OP</span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>
<span class="kw">where</span>
<span class="ident">OP</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">ScopeFifo</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>,
{
<span class="ident">do_in_place_scope_fifo</span>(<span class="prelude-val">None</span>, <span class="ident">op</span>)
}
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">do_in_place_scope_fifo</span><span class="op"><</span><span class="lifetime">'scope</span>, <span class="ident">OP</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">registry</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">Arc</span><span class="op"><</span><span class="ident">Registry</span><span class="op">></span><span class="op">></span>, <span class="ident">op</span>: <span class="ident">OP</span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>
<span class="kw">where</span>
<span class="ident">OP</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">ScopeFifo</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>,
{
<span class="kw">let</span> <span class="ident">thread</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">WorkerThread::current</span>().<span class="ident">as_ref</span>() };
<span class="kw">let</span> <span class="ident">scope</span> <span class="op">=</span> <span class="ident">ScopeFifo</span>::<span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span><span class="ident">::new</span>(<span class="ident">thread</span>, <span class="ident">registry</span>);
<span class="ident">scope</span>.<span class="ident">base</span>.<span class="ident">complete</span>(<span class="ident">thread</span>, <span class="op">|</span><span class="op">|</span> <span class="ident">op</span>(<span class="kw-2">&</span><span class="ident">scope</span>))
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> <span class="ident">Scope</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">owner</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">WorkerThread</span><span class="op">></span>, <span class="ident">registry</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">Arc</span><span class="op"><</span><span class="ident">Registry</span><span class="op">></span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="kw">let</span> <span class="ident">base</span> <span class="op">=</span> <span class="ident">ScopeBase::new</span>(<span class="ident">owner</span>, <span class="ident">registry</span>);
<span class="ident">Scope</span> { <span class="ident">base</span> }
}
<span class="doccomment">/// Spawns a job into the fork-join scope `self`. This job will</span>
<span class="doccomment">/// execute sometime before the fork-join scope completes. The</span>
<span class="doccomment">/// job is specified as a closure, and this closure receives its</span>
<span class="doccomment">/// own reference to the scope `self` as argument. This can be</span>
<span class="doccomment">/// used to inject new jobs into `self`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Returns</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Nothing. The spawned closures cannot pass back values to the</span>
<span class="doccomment">/// caller directly, though they can write to local variables on</span>
<span class="doccomment">/// the stack (if those variables outlive the scope) or</span>
<span class="doccomment">/// communicate through shared channels.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// (The intention is to eventualy integrate with Rust futures to</span>
<span class="doccomment">/// support spawns of functions that compute a value.)</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```rust</span>
<span class="doccomment">/// # use rayon_core as rayon;</span>
<span class="doccomment">/// let mut value_a = None;</span>
<span class="doccomment">/// let mut value_b = None;</span>
<span class="doccomment">/// let mut value_c = None;</span>
<span class="doccomment">/// rayon::scope(|s| {</span>
<span class="doccomment">/// s.spawn(|s1| {</span>
<span class="doccomment">/// // ^ this is the same scope as `s`; this handle `s1`</span>
<span class="doccomment">/// // is intended for use by the spawned task,</span>
<span class="doccomment">/// // since scope handles cannot cross thread boundaries.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// value_a = Some(22);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // the scope `s` will not end until all these tasks are done</span>
<span class="doccomment">/// s1.spawn(|_| {</span>
<span class="doccomment">/// value_b = Some(44);</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// });</span>
<span class="doccomment">///</span>
<span class="doccomment">/// s.spawn(|_| {</span>
<span class="doccomment">/// value_c = Some(66);</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// });</span>
<span class="doccomment">/// assert_eq!(value_a, Some(22));</span>
<span class="doccomment">/// assert_eq!(value_b, Some(44));</span>
<span class="doccomment">/// assert_eq!(value_c, Some(66));</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # See also</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The [`scope` function] has more extensive documentation about</span>
<span class="doccomment">/// task spawning.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`scope` function]: fn.scope.html</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">spawn</span><span class="op"><</span><span class="ident">BODY</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">body</span>: <span class="ident">BODY</span>)
<span class="kw">where</span>
<span class="ident">BODY</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">Scope</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>) <span class="op">+</span> <span class="ident">Send</span> <span class="op">+</span> <span class="lifetime">'scope</span>,
{
<span class="self">self</span>.<span class="ident">base</span>.<span class="ident">increment</span>();
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">job_ref</span> <span class="op">=</span> <span class="ident">Box::new</span>(<span class="ident">HeapJob::new</span>(<span class="kw">move</span> <span class="op">|</span><span class="op">|</span> {
<span class="self">self</span>.<span class="ident">base</span>.<span class="ident">execute_job</span>(<span class="kw">move</span> <span class="op">|</span><span class="op">|</span> <span class="ident">body</span>(<span class="self">self</span>))
}))
.<span class="ident">as_job_ref</span>();
<span class="comment">// Since `Scope` implements `Sync`, we can't be sure that we're still in a</span>
<span class="comment">// thread of this pool, so we can't just push to the local worker thread.</span>
<span class="comment">// Also, this might be an in-place scope.</span>
<span class="self">self</span>.<span class="ident">base</span>.<span class="ident">registry</span>.<span class="ident">inject_or_push</span>(<span class="ident">job_ref</span>);
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> <span class="ident">ScopeFifo</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">owner</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">WorkerThread</span><span class="op">></span>, <span class="ident">registry</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">Arc</span><span class="op"><</span><span class="ident">Registry</span><span class="op">></span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="kw">let</span> <span class="ident">base</span> <span class="op">=</span> <span class="ident">ScopeBase::new</span>(<span class="ident">owner</span>, <span class="ident">registry</span>);
<span class="kw">let</span> <span class="ident">num_threads</span> <span class="op">=</span> <span class="ident">base</span>.<span class="ident">registry</span>.<span class="ident">num_threads</span>();
<span class="kw">let</span> <span class="ident">fifos</span> <span class="op">=</span> (<span class="number">0</span>..<span class="ident">num_threads</span>).<span class="ident">map</span>(<span class="op">|</span><span class="kw">_</span><span class="op">|</span> <span class="ident">JobFifo::new</span>()).<span class="ident">collect</span>();
<span class="ident">ScopeFifo</span> { <span class="ident">base</span>, <span class="ident">fifos</span> }
}
<span class="doccomment">/// Spawns a job into the fork-join scope `self`. This job will</span>
<span class="doccomment">/// execute sometime before the fork-join scope completes. The</span>
<span class="doccomment">/// job is specified as a closure, and this closure receives its</span>
<span class="doccomment">/// own reference to the scope `self` as argument. This can be</span>
<span class="doccomment">/// used to inject new jobs into `self`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # See also</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This method is akin to [`Scope::spawn()`], but with a FIFO</span>
<span class="doccomment">/// priority. The [`scope_fifo` function] has more details about</span>
<span class="doccomment">/// this distinction.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`Scope::spawn()`]: struct.Scope.html#method.spawn</span>
<span class="doccomment">/// [`scope_fifo` function]: fn.scope_fifo.html</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">spawn_fifo</span><span class="op"><</span><span class="ident">BODY</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">body</span>: <span class="ident">BODY</span>)
<span class="kw">where</span>
<span class="ident">BODY</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">ScopeFifo</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span>) <span class="op">+</span> <span class="ident">Send</span> <span class="op">+</span> <span class="lifetime">'scope</span>,
{
<span class="self">self</span>.<span class="ident">base</span>.<span class="ident">increment</span>();
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">job_ref</span> <span class="op">=</span> <span class="ident">Box::new</span>(<span class="ident">HeapJob::new</span>(<span class="kw">move</span> <span class="op">|</span><span class="op">|</span> {
<span class="self">self</span>.<span class="ident">base</span>.<span class="ident">execute_job</span>(<span class="kw">move</span> <span class="op">|</span><span class="op">|</span> <span class="ident">body</span>(<span class="self">self</span>))
}))
.<span class="ident">as_job_ref</span>();
<span class="comment">// If we're in the pool, use our scope's private fifo for this thread to execute</span>
<span class="comment">// in a locally-FIFO order. Otherwise, just use the pool's global injector.</span>
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">base</span>.<span class="ident">registry</span>.<span class="ident">current_thread</span>() {
<span class="prelude-val">Some</span>(<span class="ident">worker</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">fifo</span> <span class="op">=</span> <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">fifos</span>[<span class="ident">worker</span>.<span class="ident">index</span>()];
<span class="ident">worker</span>.<span class="ident">push</span>(<span class="ident">fifo</span>.<span class="ident">push</span>(<span class="ident">job_ref</span>));
}
<span class="prelude-val">None</span> <span class="op">=</span><span class="op">></span> <span class="self">self</span>.<span class="ident">base</span>.<span class="ident">registry</span>.<span class="ident">inject</span>(<span class="kw-2">&</span>[<span class="ident">job_ref</span>]),
}
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> <span class="ident">ScopeBase</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> {
<span class="doccomment">/// Creates the base of a new scope for the given registry</span>
<span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">owner</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">WorkerThread</span><span class="op">></span>, <span class="ident">registry</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">Arc</span><span class="op"><</span><span class="ident">Registry</span><span class="op">></span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="kw">let</span> <span class="ident">registry</span> <span class="op">=</span> <span class="ident">registry</span>.<span class="ident">unwrap_or_else</span>(<span class="op">|</span><span class="op">|</span> <span class="kw">match</span> <span class="ident">owner</span> {
<span class="prelude-val">Some</span>(<span class="ident">owner</span>) <span class="op">=</span><span class="op">></span> <span class="ident">owner</span>.<span class="ident">registry</span>(),
<span class="prelude-val">None</span> <span class="op">=</span><span class="op">></span> <span class="ident">global_registry</span>(),
});
<span class="ident">ScopeBase</span> {
<span class="ident">registry</span>: <span class="ident">Arc::clone</span>(<span class="ident">registry</span>),
<span class="ident">panic</span>: <span class="ident">AtomicPtr::new</span>(<span class="ident">ptr::null_mut</span>()),
<span class="ident">job_completed_latch</span>: <span class="ident">ScopeLatch::new</span>(<span class="ident">owner</span>),
<span class="ident">marker</span>: <span class="ident">PhantomData</span>,
}
}
<span class="kw">fn</span> <span class="ident">increment</span>(<span class="kw-2">&</span><span class="self">self</span>) {
<span class="self">self</span>.<span class="ident">job_completed_latch</span>.<span class="ident">increment</span>();
}
<span class="doccomment">/// Executes `func` as a job, either aborting or executing as</span>
<span class="doccomment">/// appropriate.</span>
<span class="kw">fn</span> <span class="ident">complete</span><span class="op"><</span><span class="ident">FUNC</span>, <span class="ident">R</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">owner</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">WorkerThread</span><span class="op">></span>, <span class="ident">func</span>: <span class="ident">FUNC</span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>
<span class="kw">where</span>
<span class="ident">FUNC</span>: <span class="ident">FnOnce</span>() <span class="op">-</span><span class="op">></span> <span class="ident">R</span>,
{
<span class="kw">let</span> <span class="ident">result</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">execute_job_closure</span>(<span class="ident">func</span>);
<span class="self">self</span>.<span class="ident">job_completed_latch</span>.<span class="ident">wait</span>(<span class="ident">owner</span>);
<span class="self">self</span>.<span class="ident">maybe_propagate_panic</span>();
<span class="ident">result</span>.<span class="ident">unwrap</span>() <span class="comment">// only None if `op` panicked, and that would have been propagated</span>
}
<span class="doccomment">/// Executes `func` as a job, either aborting or executing as</span>
<span class="doccomment">/// appropriate.</span>
<span class="kw">fn</span> <span class="ident">execute_job</span><span class="op"><</span><span class="ident">FUNC</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">func</span>: <span class="ident">FUNC</span>)
<span class="kw">where</span>
<span class="ident">FUNC</span>: <span class="ident">FnOnce</span>(),
{
<span class="kw">let</span> <span class="kw">_</span>: <span class="prelude-ty">Option</span><span class="op"><</span>()<span class="op">></span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">execute_job_closure</span>(<span class="ident">func</span>);
}
<span class="doccomment">/// Executes `func` as a job in scope. Adjusts the "job completed"</span>
<span class="doccomment">/// counters and also catches any panic and stores it into</span>
<span class="doccomment">/// `scope`.</span>
<span class="kw">fn</span> <span class="ident">execute_job_closure</span><span class="op"><</span><span class="ident">FUNC</span>, <span class="ident">R</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">func</span>: <span class="ident">FUNC</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">R</span><span class="op">></span>
<span class="kw">where</span>
<span class="ident">FUNC</span>: <span class="ident">FnOnce</span>() <span class="op">-</span><span class="op">></span> <span class="ident">R</span>,
{
<span class="kw">match</span> <span class="ident">unwind::halt_unwinding</span>(<span class="ident">func</span>) {
<span class="prelude-val">Ok</span>(<span class="ident">r</span>) <span class="op">=</span><span class="op">></span> {
<span class="self">self</span>.<span class="ident">job_completed_latch</span>.<span class="ident">set</span>();
<span class="prelude-val">Some</span>(<span class="ident">r</span>)
}
<span class="prelude-val">Err</span>(<span class="ident">err</span>) <span class="op">=</span><span class="op">></span> {
<span class="self">self</span>.<span class="ident">job_panicked</span>(<span class="ident">err</span>);
<span class="self">self</span>.<span class="ident">job_completed_latch</span>.<span class="ident">set</span>();
<span class="prelude-val">None</span>
}
}
}
<span class="kw">fn</span> <span class="ident">job_panicked</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">err</span>: <span class="ident">Box</span><span class="op"><</span><span class="kw">dyn</span> <span class="ident">Any</span> <span class="op">+</span> <span class="ident">Send</span> <span class="op">+</span> <span class="lifetime">'static</span><span class="op">></span>) {
<span class="comment">// capture the first error we see, free the rest</span>
<span class="kw">let</span> <span class="ident">nil</span> <span class="op">=</span> <span class="ident">ptr::null_mut</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">err</span> <span class="op">=</span> <span class="ident">Box::new</span>(<span class="ident">err</span>); <span class="comment">// box up the fat ptr</span>
<span class="kw">if</span> <span class="self">self</span>
.<span class="ident">panic</span>
.<span class="ident">compare_exchange</span>(<span class="ident">nil</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="kw-2">*</span><span class="ident">err</span>, <span class="ident">Ordering::Release</span>, <span class="ident">Ordering::Relaxed</span>)
.<span class="ident">is_ok</span>()
{
<span class="ident">mem::forget</span>(<span class="ident">err</span>); <span class="comment">// ownership now transferred into self.panic</span>
}
}
<span class="kw">fn</span> <span class="ident">maybe_propagate_panic</span>(<span class="kw-2">&</span><span class="self">self</span>) {
<span class="comment">// propagate panic, if any occurred; at this point, all</span>
<span class="comment">// outstanding jobs have completed, so we can use a relaxed</span>
<span class="comment">// ordering:</span>
<span class="kw">let</span> <span class="ident">panic</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">panic</span>.<span class="ident">swap</span>(<span class="ident">ptr::null_mut</span>(), <span class="ident">Ordering::Relaxed</span>);
<span class="kw">if</span> <span class="op">!</span><span class="ident">panic</span>.<span class="ident">is_null</span>() {
<span class="kw">let</span> <span class="ident">value</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">Box::from_raw</span>(<span class="ident">panic</span>) };
<span class="ident">unwind::resume_unwinding</span>(<span class="kw-2">*</span><span class="ident">value</span>);
}
}
}
<span class="kw">impl</span> <span class="ident">ScopeLatch</span> {
<span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">owner</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">WorkerThread</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="kw">match</span> <span class="ident">owner</span> {
<span class="prelude-val">Some</span>(<span class="ident">owner</span>) <span class="op">=</span><span class="op">></span> <span class="ident">ScopeLatch::Stealing</span> {
<span class="ident">latch</span>: <span class="ident">CountLatch::new</span>(),
<span class="ident">registry</span>: <span class="ident">Arc::clone</span>(<span class="ident">owner</span>.<span class="ident">registry</span>()),
<span class="ident">worker_index</span>: <span class="ident">owner</span>.<span class="ident">index</span>(),
},
<span class="prelude-val">None</span> <span class="op">=</span><span class="op">></span> <span class="ident">ScopeLatch::Blocking</span> {
<span class="ident">latch</span>: <span class="ident">CountLockLatch::new</span>(),
},
}
}
<span class="kw">fn</span> <span class="ident">increment</span>(<span class="kw-2">&</span><span class="self">self</span>) {
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">ScopeLatch::Stealing</span> { <span class="ident">latch</span>, .. } <span class="op">=</span><span class="op">></span> <span class="ident">latch</span>.<span class="ident">increment</span>(),
<span class="ident">ScopeLatch::Blocking</span> { <span class="ident">latch</span> } <span class="op">=</span><span class="op">></span> <span class="ident">latch</span>.<span class="ident">increment</span>(),
}
}
<span class="kw">fn</span> <span class="ident">set</span>(<span class="kw-2">&</span><span class="self">self</span>) {
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">ScopeLatch::Stealing</span> {
<span class="ident">latch</span>,
<span class="ident">registry</span>,
<span class="ident">worker_index</span>,
} <span class="op">=</span><span class="op">></span> <span class="ident">latch</span>.<span class="ident">set_and_tickle_one</span>(<span class="ident">registry</span>, <span class="kw-2">*</span><span class="ident">worker_index</span>),
<span class="ident">ScopeLatch::Blocking</span> { <span class="ident">latch</span> } <span class="op">=</span><span class="op">></span> <span class="ident">latch</span>.<span class="ident">set</span>(),
}
}
<span class="kw">fn</span> <span class="ident">wait</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">owner</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">WorkerThread</span><span class="op">></span>) {
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">ScopeLatch::Stealing</span> {
<span class="ident">latch</span>,
<span class="ident">registry</span>,
<span class="ident">worker_index</span>,
} <span class="op">=</span><span class="op">></span> <span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">owner</span> <span class="op">=</span> <span class="ident">owner</span>.<span class="ident">expect</span>(<span class="string">"owner thread"</span>);
<span class="macro">debug_assert_eq!</span>(<span class="ident">registry</span>.<span class="ident">id</span>(), <span class="ident">owner</span>.<span class="ident">registry</span>().<span class="ident">id</span>());
<span class="macro">debug_assert_eq!</span>(<span class="kw-2">*</span><span class="ident">worker_index</span>, <span class="ident">owner</span>.<span class="ident">index</span>());
<span class="ident">owner</span>.<span class="ident">wait_until</span>(<span class="ident">latch</span>);
},
<span class="ident">ScopeLatch::Blocking</span> { <span class="ident">latch</span> } <span class="op">=</span><span class="op">></span> <span class="ident">latch</span>.<span class="ident">wait</span>(),
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> <span class="ident">fmt::Debug</span> <span class="kw">for</span> <span class="ident">Scope</span><span class="op"><</span><span class="lifetime">'scope</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">fmt</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">fmt</span>.<span class="ident">debug_struct</span>(<span class="string">"Scope"</span>)
.<span class="ident">field</span>(<span class="string">"pool_id"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">base</span>.<span class="ident">registry</span>.<span class="ident">id</span>())
.<span class="ident">field</span>(<span class="string">"panic"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">base</span>.<span class="ident">panic</span>)
.<span class="ident">field</span>(<span class="string">"job_completed_latch"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">base</span>.<span class="ident">job_completed_latch</span>)
.<span class="ident">finish</span>()
}
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'scope</span><span class="op">></span> <span class="ident">fmt::Debug</span> <span class="kw">for</span> <span class="ident">ScopeFifo</span><span class="op"><</span><span class="lifetime">'scope</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">fmt</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">fmt</span>.<span class="ident">debug_struct</span>(<span class="string">"ScopeFifo"</span>)
.<span class="ident">field</span>(<span class="string">"num_fifos"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">fifos</span>.<span class="ident">len</span>())
.<span class="ident">field</span>(<span class="string">"pool_id"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">base</span>.<span class="ident">registry</span>.<span class="ident">id</span>())
.<span class="ident">field</span>(<span class="string">"panic"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">base</span>.<span class="ident">panic</span>)
.<span class="ident">field</span>(<span class="string">"job_completed_latch"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">base</span>.<span class="ident">job_completed_latch</span>)
.<span class="ident">finish</span>()
}
}
<span class="kw">impl</span> <span class="ident">fmt::Debug</span> <span class="kw">for</span> <span class="ident">ScopeLatch</span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">fmt</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="kw">match</span> <span class="self">self</span> {
<span class="ident">ScopeLatch::Stealing</span> { <span class="ident">latch</span>, .. } <span class="op">=</span><span class="op">></span> <span class="ident">fmt</span>
.<span class="ident">debug_tuple</span>(<span class="string">"ScopeLatch::Stealing"</span>)
.<span class="ident">field</span>(<span class="ident">latch</span>)
.<span class="ident">finish</span>(),
<span class="ident">ScopeLatch::Blocking</span> { <span class="ident">latch</span> } <span class="op">=</span><span class="op">></span> <span class="ident">fmt</span>
.<span class="ident">debug_tuple</span>(<span class="string">"ScopeLatch::Blocking"</span>)
.<span class="ident">field</span>(<span class="ident">latch</span>)
.<span class="ident">finish</span>(),
}
}
}
</pre></div>
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