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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
| commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
| tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/futures-util | |
| parent | Initial commit. (diff) | |
| download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip | |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/futures-util')
187 files changed, 25561 insertions, 0 deletions
diff --git a/third_party/rust/futures-util/.cargo-checksum.json b/third_party/rust/futures-util/.cargo-checksum.json new file mode 100644 index 0000000000..93b61c8fc0 --- /dev/null +++ b/third_party/rust/futures-util/.cargo-checksum.json @@ -0,0 +1 @@ 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\ No newline at end of file diff --git a/third_party/rust/futures-util/Cargo.toml b/third_party/rust/futures-util/Cargo.toml new file mode 100644 index 0000000000..47e9f55125 --- /dev/null +++ b/third_party/rust/futures-util/Cargo.toml @@ -0,0 +1,135 @@ +# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO +# +# When uploading crates to the registry Cargo will automatically +# "normalize" Cargo.toml files for maximal compatibility +# with all versions of Cargo and also rewrite `path` dependencies +# to registry (e.g., crates.io) dependencies. +# +# If you are reading this file be aware that the original Cargo.toml +# will likely look very different (and much more reasonable). +# See Cargo.toml.orig for the original contents. + +[package] +edition = "2018" +rust-version = "1.45" +name = "futures-util" +version = "0.3.26" +description = """ +Common utilities and extension traits for the futures-rs library. +""" +homepage = "https://rust-lang.github.io/futures-rs" +readme = "README.md" +license = "MIT OR Apache-2.0" +repository = "https://github.com/rust-lang/futures-rs" + +[package.metadata.docs.rs] +all-features = true +rustdoc-args = [ + "--cfg", + "docsrs", +] + +[dependencies.futures-channel] +version = "0.3.26" +features = ["std"] +optional = true +default-features = false + +[dependencies.futures-core] +version = "0.3.26" +default-features = false + +[dependencies.futures-io] +version = "0.3.26" +features = ["std"] +optional = true +default-features = false + +[dependencies.futures-macro] +version = "=0.3.26" +optional = true +default-features = false + +[dependencies.futures-sink] +version = "0.3.26" +optional = true +default-features = false + +[dependencies.futures-task] +version = "0.3.26" +default-features = false + +[dependencies.futures_01] +version = "0.1.25" +optional = true +package = "futures" + +[dependencies.memchr] +version = "2.2" +optional = true + +[dependencies.pin-project-lite] +version = "0.2.6" + +[dependencies.pin-utils] +version = "0.1.0" + +[dependencies.slab] +version = "0.4.2" +optional = true + +[dependencies.tokio-io] +version = "0.1.9" +optional = true + +[dev-dependencies.tokio] +version = "0.1.11" + +[features] +alloc = [ + "futures-core/alloc", + "futures-task/alloc", +] +async-await = [] +async-await-macro = [ + "async-await", + "futures-macro", +] +bilock = [] +cfg-target-has-atomic = [] +channel = [ + "std", + "futures-channel", +] +compat = [ + "std", + "futures_01", +] +default = [ + "std", + "async-await", + "async-await-macro", +] +io = [ + "std", + "futures-io", + "memchr", +] +io-compat = [ + "io", + "compat", + "tokio-io", +] +portable-atomic = ["futures-core/portable-atomic"] +sink = ["futures-sink"] +std = [ + "alloc", + "futures-core/std", + "futures-task/std", + "slab", +] +unstable = [ + "futures-core/unstable", + "futures-task/unstable", +] +write-all-vectored = ["io"] diff --git a/third_party/rust/futures-util/LICENSE-APACHE b/third_party/rust/futures-util/LICENSE-APACHE new file mode 100644 index 0000000000..9eb0b097f5 --- /dev/null +++ b/third_party/rust/futures-util/LICENSE-APACHE @@ -0,0 +1,202 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + +TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + +1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + +Copyright (c) 2016 Alex Crichton +Copyright (c) 2017 The Tokio Authors + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. diff --git a/third_party/rust/futures-util/LICENSE-MIT b/third_party/rust/futures-util/LICENSE-MIT new file mode 100644 index 0000000000..8ad082ec4f --- /dev/null +++ b/third_party/rust/futures-util/LICENSE-MIT @@ -0,0 +1,26 @@ +Copyright (c) 2016 Alex Crichton +Copyright (c) 2017 The Tokio Authors + +Permission is hereby granted, free of charge, to any +person obtaining a copy of this software and associated +documentation files (the "Software"), to deal in the +Software without restriction, including without +limitation the rights to use, copy, modify, merge, +publish, distribute, sublicense, and/or sell copies of +the Software, and to permit persons to whom the Software +is furnished to do so, subject to the following +conditions: + +The above copyright notice and this permission notice +shall be included in all copies or substantial portions +of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF +ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED +TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A +PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT +SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR +IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. diff --git a/third_party/rust/futures-util/README.md b/third_party/rust/futures-util/README.md new file mode 100644 index 0000000000..6e0aaed847 --- /dev/null +++ b/third_party/rust/futures-util/README.md @@ -0,0 +1,23 @@ +# futures-util + +Common utilities and extension traits for the futures-rs library. + +## Usage + +Add this to your `Cargo.toml`: + +```toml +[dependencies] +futures-util = "0.3" +``` + +The current `futures-util` requires Rust 1.45 or later. + +## License + +Licensed under either of [Apache License, Version 2.0](LICENSE-APACHE) or +[MIT license](LICENSE-MIT) at your option. + +Unless you explicitly state otherwise, any contribution intentionally submitted +for inclusion in the work by you, as defined in the Apache-2.0 license, shall +be dual licensed as above, without any additional terms or conditions. diff --git a/third_party/rust/futures-util/benches/flatten_unordered.rs b/third_party/rust/futures-util/benches/flatten_unordered.rs new file mode 100644 index 0000000000..64d5f9a4e3 --- /dev/null +++ b/third_party/rust/futures-util/benches/flatten_unordered.rs @@ -0,0 +1,66 @@ +#![feature(test)] + +extern crate test; +use crate::test::Bencher; + +use futures::channel::oneshot; +use futures::executor::block_on; +use futures::future::{self, FutureExt}; +use futures::stream::{self, StreamExt}; +use futures::task::Poll; +use std::collections::VecDeque; +use std::thread; + +#[bench] +fn oneshot_streams(b: &mut Bencher) { + const STREAM_COUNT: usize = 10_000; + const STREAM_ITEM_COUNT: usize = 1; + + b.iter(|| { + let mut txs = VecDeque::with_capacity(STREAM_COUNT); + let mut rxs = Vec::new(); + + for _ in 0..STREAM_COUNT { + let (tx, rx) = oneshot::channel(); + txs.push_back(tx); + rxs.push(rx); + } + + thread::spawn(move || { + let mut last = 1; + while let Some(tx) = txs.pop_front() { + let _ = tx.send(stream::iter(last..last + STREAM_ITEM_COUNT)); + last += STREAM_ITEM_COUNT; + } + }); + + let mut flatten = stream::unfold(rxs.into_iter(), |mut vals| { + async { + if let Some(next) = vals.next() { + let val = next.await.unwrap(); + Some((val, vals)) + } else { + None + } + } + .boxed() + }) + .flatten_unordered(None); + + block_on(future::poll_fn(move |cx| { + let mut count = 0; + loop { + match flatten.poll_next_unpin(cx) { + Poll::Ready(None) => break, + Poll::Ready(Some(_)) => { + count += 1; + } + _ => {} + } + } + assert_eq!(count, STREAM_COUNT * STREAM_ITEM_COUNT); + + Poll::Ready(()) + })) + }); +} diff --git a/third_party/rust/futures-util/benches/futures_unordered.rs b/third_party/rust/futures-util/benches/futures_unordered.rs new file mode 100644 index 0000000000..d5fe7a59de --- /dev/null +++ b/third_party/rust/futures-util/benches/futures_unordered.rs @@ -0,0 +1,43 @@ +#![feature(test)] + +extern crate test; +use crate::test::Bencher; + +use futures::channel::oneshot; +use futures::executor::block_on; +use futures::future; +use futures::stream::{FuturesUnordered, StreamExt}; +use futures::task::Poll; +use std::collections::VecDeque; +use std::thread; + +#[bench] +fn oneshots(b: &mut Bencher) { + const NUM: usize = 10_000; + + b.iter(|| { + let mut txs = VecDeque::with_capacity(NUM); + let mut rxs = FuturesUnordered::new(); + + for _ in 0..NUM { + let (tx, rx) = oneshot::channel(); + txs.push_back(tx); + rxs.push(rx); + } + + thread::spawn(move || { + while let Some(tx) = txs.pop_front() { + let _ = tx.send("hello"); + } + }); + + block_on(future::poll_fn(move |cx| { + loop { + if let Poll::Ready(None) = rxs.poll_next_unpin(cx) { + break; + } + } + Poll::Ready(()) + })) + }); +} diff --git a/third_party/rust/futures-util/benches/select.rs b/third_party/rust/futures-util/benches/select.rs new file mode 100644 index 0000000000..5410a95299 --- /dev/null +++ b/third_party/rust/futures-util/benches/select.rs @@ -0,0 +1,35 @@ +#![feature(test)] + +extern crate test; +use crate::test::Bencher; + +use futures::executor::block_on; +use futures::stream::{repeat, select, StreamExt}; + +#[bench] +fn select_streams(b: &mut Bencher) { + const STREAM_COUNT: usize = 10_000; + + b.iter(|| { + let stream1 = repeat(1).take(STREAM_COUNT); + let stream2 = repeat(2).take(STREAM_COUNT); + let stream3 = repeat(3).take(STREAM_COUNT); + let stream4 = repeat(4).take(STREAM_COUNT); + let stream5 = repeat(5).take(STREAM_COUNT); + let stream6 = repeat(6).take(STREAM_COUNT); + let stream7 = repeat(7).take(STREAM_COUNT); + let count = block_on(async { + let count = select( + stream1, + select( + stream2, + select(stream3, select(stream4, select(stream5, select(stream6, stream7)))), + ), + ) + .count() + .await; + count + }); + assert_eq!(count, STREAM_COUNT * 7); + }); +} diff --git a/third_party/rust/futures-util/benches_disabled/bilock.rs b/third_party/rust/futures-util/benches_disabled/bilock.rs new file mode 100644 index 0000000000..417f75d31e --- /dev/null +++ b/third_party/rust/futures-util/benches_disabled/bilock.rs @@ -0,0 +1,122 @@ +#![feature(test)] + +#[cfg(feature = "bilock")] +mod bench { + use futures::executor::LocalPool; + use futures::task::{Context, Waker}; + use futures_util::lock::BiLock; + use futures_util::lock::BiLockAcquire; + use futures_util::lock::BiLockAcquired; + use futures_util::task::ArcWake; + + use std::sync::Arc; + use test::Bencher; + + fn notify_noop() -> Waker { + struct Noop; + + impl ArcWake for Noop { + fn wake(_: &Arc<Self>) {} + } + + ArcWake::into_waker(Arc::new(Noop)) + } + + /// Pseudo-stream which simply calls `lock.poll()` on `poll` + struct LockStream { + lock: BiLockAcquire<u32>, + } + + impl LockStream { + fn new(lock: BiLock<u32>) -> Self { + Self { lock: lock.lock() } + } + + /// Release a lock after it was acquired in `poll`, + /// so `poll` could be called again. + fn release_lock(&mut self, guard: BiLockAcquired<u32>) { + self.lock = guard.unlock().lock() + } + } + + impl Stream for LockStream { + type Item = BiLockAcquired<u32>; + type Error = (); + + fn poll_next(&mut self, cx: &mut Context<'_>) -> Poll<Option<Self::Item>, Self::Error> { + self.lock.poll(cx).map(|a| a.map(Some)) + } + } + + #[bench] + fn contended(b: &mut Bencher) { + let pool = LocalPool::new(); + let mut exec = pool.executor(); + let waker = notify_noop(); + let mut map = task::LocalMap::new(); + let mut waker = task::Context::new(&mut map, &waker, &mut exec); + + b.iter(|| { + let (x, y) = BiLock::new(1); + + let mut x = LockStream::new(x); + let mut y = LockStream::new(y); + + for _ in 0..1000 { + let x_guard = match x.poll_next(&mut waker) { + Ok(Poll::Ready(Some(guard))) => guard, + _ => panic!(), + }; + + // Try poll second lock while first lock still holds the lock + match y.poll_next(&mut waker) { + Ok(Poll::Pending) => (), + _ => panic!(), + }; + + x.release_lock(x_guard); + + let y_guard = match y.poll_next(&mut waker) { + Ok(Poll::Ready(Some(guard))) => guard, + _ => panic!(), + }; + + y.release_lock(y_guard); + } + (x, y) + }); + } + + #[bench] + fn lock_unlock(b: &mut Bencher) { + let pool = LocalPool::new(); + let mut exec = pool.executor(); + let waker = notify_noop(); + let mut map = task::LocalMap::new(); + let mut waker = task::Context::new(&mut map, &waker, &mut exec); + + b.iter(|| { + let (x, y) = BiLock::new(1); + + let mut x = LockStream::new(x); + let mut y = LockStream::new(y); + + for _ in 0..1000 { + let x_guard = match x.poll_next(&mut waker) { + Ok(Poll::Ready(Some(guard))) => guard, + _ => panic!(), + }; + + x.release_lock(x_guard); + + let y_guard = match y.poll_next(&mut waker) { + Ok(Poll::Ready(Some(guard))) => guard, + _ => panic!(), + }; + + y.release_lock(y_guard); + } + (x, y) + }) + } +} diff --git a/third_party/rust/futures-util/build.rs b/third_party/rust/futures-util/build.rs new file mode 100644 index 0000000000..05e0496d94 --- /dev/null +++ b/third_party/rust/futures-util/build.rs @@ -0,0 +1,41 @@ +// The rustc-cfg listed below are considered public API, but it is *unstable* +// and outside of the normal semver guarantees: +// +// - `futures_no_atomic_cas` +// Assume the target does *not* support atomic CAS operations. +// This is usually detected automatically by the build script, but you may +// need to enable it manually when building for custom targets or using +// non-cargo build systems that don't run the build script. +// +// With the exceptions mentioned above, the rustc-cfg emitted by the build +// script are *not* public API. + +#![warn(rust_2018_idioms, single_use_lifetimes)] + +use std::env; + +include!("no_atomic_cas.rs"); + +fn main() { + let target = match env::var("TARGET") { + Ok(target) => target, + Err(e) => { + println!( + "cargo:warning={}: unable to get TARGET environment variable: {}", + env!("CARGO_PKG_NAME"), + e + ); + return; + } + }; + + // Note that this is `no_*`, not `has_*`. This allows treating + // `cfg(target_has_atomic = "ptr")` as true when the build script doesn't + // run. This is needed for compatibility with non-cargo build systems that + // don't run the build script. + if NO_ATOMIC_CAS.contains(&&*target) { + println!("cargo:rustc-cfg=futures_no_atomic_cas"); + } + + println!("cargo:rerun-if-changed=no_atomic_cas.rs"); +} diff --git a/third_party/rust/futures-util/no_atomic_cas.rs b/third_party/rust/futures-util/no_atomic_cas.rs new file mode 100644 index 0000000000..16ec628cdf --- /dev/null +++ b/third_party/rust/futures-util/no_atomic_cas.rs @@ -0,0 +1,17 @@ +// This file is @generated by no_atomic_cas.sh. +// It is not intended for manual editing. + +const NO_ATOMIC_CAS: &[&str] = &[ + "armv4t-none-eabi", + "armv5te-none-eabi", + "avr-unknown-gnu-atmega328", + "bpfeb-unknown-none", + "bpfel-unknown-none", + "msp430-none-elf", + "riscv32i-unknown-none-elf", + "riscv32im-unknown-none-elf", + "riscv32imc-unknown-none-elf", + "thumbv4t-none-eabi", + "thumbv5te-none-eabi", + "thumbv6m-none-eabi", +]; diff --git a/third_party/rust/futures-util/src/abortable.rs b/third_party/rust/futures-util/src/abortable.rs new file mode 100644 index 0000000000..e0afd47218 --- /dev/null +++ b/third_party/rust/futures-util/src/abortable.rs @@ -0,0 +1,185 @@ +use crate::task::AtomicWaker; +use alloc::sync::Arc; +use core::fmt; +use core::pin::Pin; +use core::sync::atomic::{AtomicBool, Ordering}; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use futures_core::Stream; +use pin_project_lite::pin_project; + +pin_project! { + /// A future/stream which can be remotely short-circuited using an `AbortHandle`. + #[derive(Debug, Clone)] + #[must_use = "futures/streams do nothing unless you poll them"] + pub struct Abortable<T> { + #[pin] + task: T, + inner: Arc<AbortInner>, + } +} + +impl<T> Abortable<T> { + /// Creates a new `Abortable` future/stream using an existing `AbortRegistration`. + /// `AbortRegistration`s can be acquired through `AbortHandle::new`. + /// + /// When `abort` is called on the handle tied to `reg` or if `abort` has + /// already been called, the future/stream will complete immediately without making + /// any further progress. + /// + /// # Examples: + /// + /// Usage with futures: + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::{Abortable, AbortHandle, Aborted}; + /// + /// let (abort_handle, abort_registration) = AbortHandle::new_pair(); + /// let future = Abortable::new(async { 2 }, abort_registration); + /// abort_handle.abort(); + /// assert_eq!(future.await, Err(Aborted)); + /// # }); + /// ``` + /// + /// Usage with streams: + /// + /// ``` + /// # futures::executor::block_on(async { + /// # use futures::future::{Abortable, AbortHandle}; + /// # use futures::stream::{self, StreamExt}; + /// + /// let (abort_handle, abort_registration) = AbortHandle::new_pair(); + /// let mut stream = Abortable::new(stream::iter(vec![1, 2, 3]), abort_registration); + /// abort_handle.abort(); + /// assert_eq!(stream.next().await, None); + /// # }); + /// ``` + pub fn new(task: T, reg: AbortRegistration) -> Self { + Self { task, inner: reg.inner } + } + + /// Checks whether the task has been aborted. Note that all this + /// method indicates is whether [`AbortHandle::abort`] was *called*. + /// This means that it will return `true` even if: + /// * `abort` was called after the task had completed. + /// * `abort` was called while the task was being polled - the task may still be running and + /// will not be stopped until `poll` returns. + pub fn is_aborted(&self) -> bool { + self.inner.aborted.load(Ordering::Relaxed) + } +} + +/// A registration handle for an `Abortable` task. +/// Values of this type can be acquired from `AbortHandle::new` and are used +/// in calls to `Abortable::new`. +#[derive(Debug)] +pub struct AbortRegistration { + pub(crate) inner: Arc<AbortInner>, +} + +/// A handle to an `Abortable` task. +#[derive(Debug, Clone)] +pub struct AbortHandle { + inner: Arc<AbortInner>, +} + +impl AbortHandle { + /// Creates an (`AbortHandle`, `AbortRegistration`) pair which can be used + /// to abort a running future or stream. + /// + /// This function is usually paired with a call to [`Abortable::new`]. + pub fn new_pair() -> (Self, AbortRegistration) { + let inner = + Arc::new(AbortInner { waker: AtomicWaker::new(), aborted: AtomicBool::new(false) }); + + (Self { inner: inner.clone() }, AbortRegistration { inner }) + } +} + +// Inner type storing the waker to awaken and a bool indicating that it +// should be aborted. +#[derive(Debug)] +pub(crate) struct AbortInner { + pub(crate) waker: AtomicWaker, + pub(crate) aborted: AtomicBool, +} + +/// Indicator that the `Abortable` task was aborted. +#[derive(Copy, Clone, Debug, Eq, PartialEq)] +pub struct Aborted; + +impl fmt::Display for Aborted { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "`Abortable` future has been aborted") + } +} + +#[cfg(feature = "std")] +impl std::error::Error for Aborted {} + +impl<T> Abortable<T> { + fn try_poll<I>( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + poll: impl Fn(Pin<&mut T>, &mut Context<'_>) -> Poll<I>, + ) -> Poll<Result<I, Aborted>> { + // Check if the task has been aborted + if self.is_aborted() { + return Poll::Ready(Err(Aborted)); + } + + // attempt to complete the task + if let Poll::Ready(x) = poll(self.as_mut().project().task, cx) { + return Poll::Ready(Ok(x)); + } + + // Register to receive a wakeup if the task is aborted in the future + self.inner.waker.register(cx.waker()); + + // Check to see if the task was aborted between the first check and + // registration. + // Checking with `is_aborted` which uses `Relaxed` is sufficient because + // `register` introduces an `AcqRel` barrier. + if self.is_aborted() { + return Poll::Ready(Err(Aborted)); + } + + Poll::Pending + } +} + +impl<Fut> Future for Abortable<Fut> +where + Fut: Future, +{ + type Output = Result<Fut::Output, Aborted>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + self.try_poll(cx, |fut, cx| fut.poll(cx)) + } +} + +impl<St> Stream for Abortable<St> +where + St: Stream, +{ + type Item = St::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + self.try_poll(cx, |stream, cx| stream.poll_next(cx)).map(Result::ok).map(Option::flatten) + } +} + +impl AbortHandle { + /// Abort the `Abortable` stream/future associated with this handle. + /// + /// Notifies the Abortable task associated with this handle that it + /// should abort. Note that if the task is currently being polled on + /// another thread, it will not immediately stop running. Instead, it will + /// continue to run until its poll method returns. + pub fn abort(&self) { + self.inner.aborted.store(true, Ordering::Relaxed); + self.inner.waker.wake(); + } +} diff --git a/third_party/rust/futures-util/src/async_await/join_mod.rs b/third_party/rust/futures-util/src/async_await/join_mod.rs new file mode 100644 index 0000000000..28f3b232e7 --- /dev/null +++ b/third_party/rust/futures-util/src/async_await/join_mod.rs @@ -0,0 +1,110 @@ +//! The `join` macro. + +macro_rules! document_join_macro { + ($join:item $try_join:item) => { + /// Polls multiple futures simultaneously, returning a tuple + /// of all results once complete. + /// + /// While `join!(a, b)` is similar to `(a.await, b.await)`, + /// `join!` polls both futures concurrently and therefore is more efficient. + /// + /// This macro is only usable inside of async functions, closures, and blocks. + /// It is also gated behind the `async-await` feature of this library, which is + /// activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::join; + /// + /// let a = async { 1 }; + /// let b = async { 2 }; + /// assert_eq!(join!(a, b), (1, 2)); + /// + /// // `join!` is variadic, so you can pass any number of futures + /// let c = async { 3 }; + /// let d = async { 4 }; + /// let e = async { 5 }; + /// assert_eq!(join!(c, d, e), (3, 4, 5)); + /// # }); + /// ``` + $join + + /// Polls multiple futures simultaneously, resolving to a [`Result`] containing + /// either a tuple of the successful outputs or an error. + /// + /// `try_join!` is similar to [`join!`], but completes immediately if any of + /// the futures return an error. + /// + /// This macro is only usable inside of async functions, closures, and blocks. + /// It is also gated behind the `async-await` feature of this library, which is + /// activated by default. + /// + /// # Examples + /// + /// When used on multiple futures that return `Ok`, `try_join!` will return + /// `Ok` of a tuple of the values: + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::try_join; + /// + /// let a = async { Ok::<i32, i32>(1) }; + /// let b = async { Ok::<i32, i32>(2) }; + /// assert_eq!(try_join!(a, b), Ok((1, 2))); + /// + /// // `try_join!` is variadic, so you can pass any number of futures + /// let c = async { Ok::<i32, i32>(3) }; + /// let d = async { Ok::<i32, i32>(4) }; + /// let e = async { Ok::<i32, i32>(5) }; + /// assert_eq!(try_join!(c, d, e), Ok((3, 4, 5))); + /// # }); + /// ``` + /// + /// If one of the futures resolves to an error, `try_join!` will return + /// that error: + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::try_join; + /// + /// let a = async { Ok::<i32, i32>(1) }; + /// let b = async { Err::<u64, i32>(2) }; + /// + /// assert_eq!(try_join!(a, b), Err(2)); + /// # }); + /// ``` + $try_join + } +} + +#[allow(unreachable_pub)] +#[doc(hidden)] +pub use futures_macro::join_internal; + +#[allow(unreachable_pub)] +#[doc(hidden)] +pub use futures_macro::try_join_internal; + +document_join_macro! { + #[macro_export] + macro_rules! join { + ($($tokens:tt)*) => {{ + use $crate::__private as __futures_crate; + $crate::join_internal! { + $( $tokens )* + } + }} + } + + #[macro_export] + macro_rules! try_join { + ($($tokens:tt)*) => {{ + use $crate::__private as __futures_crate; + $crate::try_join_internal! { + $( $tokens )* + } + }} + } +} diff --git a/third_party/rust/futures-util/src/async_await/mod.rs b/third_party/rust/futures-util/src/async_await/mod.rs new file mode 100644 index 0000000000..7276da227a --- /dev/null +++ b/third_party/rust/futures-util/src/async_await/mod.rs @@ -0,0 +1,58 @@ +//! Await +//! +//! This module contains a number of functions and combinators for working +//! with `async`/`await` code. + +use futures_core::future::{FusedFuture, Future}; +use futures_core::stream::{FusedStream, Stream}; + +#[macro_use] +mod poll; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/64762 +pub use self::poll::*; + +#[macro_use] +mod pending; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/64762 +pub use self::pending::*; + +// Primary export is a macro +#[cfg(feature = "async-await-macro")] +mod join_mod; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/64762 +#[cfg(feature = "async-await-macro")] +pub use self::join_mod::*; + +// Primary export is a macro +#[cfg(feature = "async-await-macro")] +mod select_mod; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/64762 +#[cfg(feature = "async-await-macro")] +pub use self::select_mod::*; + +// Primary export is a macro +#[cfg(feature = "async-await-macro")] +mod stream_select_mod; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/64762 +#[cfg(feature = "async-await-macro")] +pub use self::stream_select_mod::*; + +#[cfg(feature = "std")] +#[cfg(feature = "async-await-macro")] +mod random; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/64762 +#[cfg(feature = "std")] +#[cfg(feature = "async-await-macro")] +pub use self::random::*; + +#[doc(hidden)] +#[inline(always)] +pub fn assert_unpin<T: Unpin>(_: &T) {} + +#[doc(hidden)] +#[inline(always)] +pub fn assert_fused_future<T: Future + FusedFuture>(_: &T) {} + +#[doc(hidden)] +#[inline(always)] +pub fn assert_fused_stream<T: Stream + FusedStream>(_: &T) {} diff --git a/third_party/rust/futures-util/src/async_await/pending.rs b/third_party/rust/futures-util/src/async_await/pending.rs new file mode 100644 index 0000000000..5d7a431811 --- /dev/null +++ b/third_party/rust/futures-util/src/async_await/pending.rs @@ -0,0 +1,43 @@ +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; + +/// A macro which yields to the event loop once. +/// +/// This is equivalent to returning [`Poll::Pending`](futures_core::task::Poll) +/// from a [`Future::poll`](futures_core::future::Future::poll) implementation. +/// Similarly, when using this macro, it must be ensured that [`wake`](std::task::Waker::wake) +/// is called somewhere when further progress can be made. +/// +/// This macro is only usable inside of async functions, closures, and blocks. +/// It is also gated behind the `async-await` feature of this library, which is +/// activated by default. +#[macro_export] +macro_rules! pending { + () => { + $crate::__private::async_await::pending_once().await + }; +} + +#[doc(hidden)] +pub fn pending_once() -> PendingOnce { + PendingOnce { is_ready: false } +} + +#[allow(missing_debug_implementations)] +#[doc(hidden)] +pub struct PendingOnce { + is_ready: bool, +} + +impl Future for PendingOnce { + type Output = (); + fn poll(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Self::Output> { + if self.is_ready { + Poll::Ready(()) + } else { + self.is_ready = true; + Poll::Pending + } + } +} diff --git a/third_party/rust/futures-util/src/async_await/poll.rs b/third_party/rust/futures-util/src/async_await/poll.rs new file mode 100644 index 0000000000..b62f45a943 --- /dev/null +++ b/third_party/rust/futures-util/src/async_await/poll.rs @@ -0,0 +1,39 @@ +use crate::future::FutureExt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; + +/// A macro which returns the result of polling a future once within the +/// current `async` context. +/// +/// This macro is only usable inside of `async` functions, closures, and blocks. +/// It is also gated behind the `async-await` feature of this library, which is +/// activated by default. +/// +/// If you need the result of polling a [`Stream`](crate::stream::Stream), +/// you can use this macro with the [`next`](crate::stream::StreamExt::next) method: +/// `poll!(stream.next())`. +#[macro_export] +macro_rules! poll { + ($x:expr $(,)?) => { + $crate::__private::async_await::poll($x).await + }; +} + +#[doc(hidden)] +pub fn poll<F: Future + Unpin>(future: F) -> PollOnce<F> { + PollOnce { future } +} + +#[allow(missing_debug_implementations)] +#[doc(hidden)] +pub struct PollOnce<F: Future + Unpin> { + future: F, +} + +impl<F: Future + Unpin> Future for PollOnce<F> { + type Output = Poll<F::Output>; + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + Poll::Ready(self.future.poll_unpin(cx)) + } +} diff --git a/third_party/rust/futures-util/src/async_await/random.rs b/third_party/rust/futures-util/src/async_await/random.rs new file mode 100644 index 0000000000..4f8c7254b4 --- /dev/null +++ b/third_party/rust/futures-util/src/async_await/random.rs @@ -0,0 +1,54 @@ +use std::{ + cell::Cell, + collections::hash_map::DefaultHasher, + hash::Hasher, + num::Wrapping, + sync::atomic::{AtomicUsize, Ordering}, +}; + +// Based on [Fisher–Yates shuffle]. +// +// [Fisher–Yates shuffle]: https://en.wikipedia.org/wiki/Fisher–Yates_shuffle +#[doc(hidden)] +pub fn shuffle<T>(slice: &mut [T]) { + for i in (1..slice.len()).rev() { + slice.swap(i, gen_index(i + 1)); + } +} + +/// Return a value from `0..n`. +fn gen_index(n: usize) -> usize { + (random() % n as u64) as usize +} + +/// Pseudorandom number generator based on [xorshift*]. +/// +/// [xorshift*]: https://en.wikipedia.org/wiki/Xorshift#xorshift* +fn random() -> u64 { + thread_local! { + static RNG: Cell<Wrapping<u64>> = Cell::new(Wrapping(prng_seed())); + } + + fn prng_seed() -> u64 { + static COUNTER: AtomicUsize = AtomicUsize::new(0); + + // Any non-zero seed will do + let mut seed = 0; + while seed == 0 { + let mut hasher = DefaultHasher::new(); + hasher.write_usize(COUNTER.fetch_add(1, Ordering::Relaxed)); + seed = hasher.finish(); + } + seed + } + + RNG.with(|rng| { + let mut x = rng.get(); + debug_assert_ne!(x.0, 0); + x ^= x >> 12; + x ^= x << 25; + x ^= x >> 27; + rng.set(x); + x.0.wrapping_mul(0x2545_f491_4f6c_dd1d) + }) +} diff --git a/third_party/rust/futures-util/src/async_await/select_mod.rs b/third_party/rust/futures-util/src/async_await/select_mod.rs new file mode 100644 index 0000000000..1d13067d38 --- /dev/null +++ b/third_party/rust/futures-util/src/async_await/select_mod.rs @@ -0,0 +1,336 @@ +//! The `select` macro. + +macro_rules! document_select_macro { + // This branch is required for `futures 0.3.1`, from before select_biased was introduced + ($select:item) => { + /// Polls multiple futures and streams simultaneously, executing the branch + /// for the future that finishes first. If multiple futures are ready, + /// one will be pseudo-randomly selected at runtime. Futures directly + /// passed to `select!` must be `Unpin` and implement `FusedFuture`. + /// + /// If an expression which yields a `Future` is passed to `select!` + /// (e.g. an `async fn` call) instead of a `Future` by name the `Unpin` + /// requirement is relaxed, since the macro will pin the resulting `Future` + /// on the stack. However the `Future` returned by the expression must + /// still implement `FusedFuture`. + /// + /// Futures and streams which are not already fused can be fused using the + /// `.fuse()` method. Note, though, that fusing a future or stream directly + /// in the call to `select!` will not be enough to prevent it from being + /// polled after completion if the `select!` call is in a loop, so when + /// `select!`ing in a loop, users should take care to `fuse()` outside of + /// the loop. + /// + /// `select!` can be used as an expression and will return the return + /// value of the selected branch. For this reason the return type of every + /// branch in a `select!` must be the same. + /// + /// This macro is only usable inside of async functions, closures, and blocks. + /// It is also gated behind the `async-await` feature of this library, which is + /// activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::select; + /// let mut a = future::ready(4); + /// let mut b = future::pending::<()>(); + /// + /// let res = select! { + /// a_res = a => a_res + 1, + /// _ = b => 0, + /// }; + /// assert_eq!(res, 5); + /// # }); + /// ``` + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt}; + /// use futures::select; + /// let mut st = stream::iter(vec![2]).fuse(); + /// let mut fut = future::pending::<()>(); + /// + /// select! { + /// x = st.next() => assert_eq!(Some(2), x), + /// _ = fut => panic!(), + /// }; + /// # }); + /// ``` + /// + /// As described earlier, `select` can directly select on expressions + /// which return `Future`s - even if those do not implement `Unpin`: + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// use futures::select; + /// + /// // Calling the following async fn returns a Future which does not + /// // implement Unpin + /// async fn async_identity_fn(arg: usize) -> usize { + /// arg + /// } + /// + /// let res = select! { + /// a_res = async_identity_fn(62).fuse() => a_res + 1, + /// b_res = async_identity_fn(13).fuse() => b_res, + /// }; + /// assert!(res == 63 || res == 13); + /// # }); + /// ``` + /// + /// If a similar async function is called outside of `select` to produce + /// a `Future`, the `Future` must be pinned in order to be able to pass + /// it to `select`. This can be achieved via `Box::pin` for pinning a + /// `Future` on the heap or the `pin_mut!` macro for pinning a `Future` + /// on the stack. + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// use futures::select; + /// use futures::pin_mut; + /// + /// // Calling the following async fn returns a Future which does not + /// // implement Unpin + /// async fn async_identity_fn(arg: usize) -> usize { + /// arg + /// } + /// + /// let fut_1 = async_identity_fn(1).fuse(); + /// let fut_2 = async_identity_fn(2).fuse(); + /// let mut fut_1 = Box::pin(fut_1); // Pins the Future on the heap + /// pin_mut!(fut_2); // Pins the Future on the stack + /// + /// let res = select! { + /// a_res = fut_1 => a_res, + /// b_res = fut_2 => b_res, + /// }; + /// assert!(res == 1 || res == 2); + /// # }); + /// ``` + /// + /// `select` also accepts a `complete` branch and a `default` branch. + /// `complete` will run if all futures and streams have already been + /// exhausted. `default` will run if no futures or streams are + /// immediately ready. `complete` takes priority over `default` in + /// the case where all futures have completed. + /// A motivating use-case for passing `Future`s by name as well as for + /// `complete` blocks is to call `select!` in a loop, which is + /// demonstrated in the following example: + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::select; + /// let mut a_fut = future::ready(4); + /// let mut b_fut = future::ready(6); + /// let mut total = 0; + /// + /// loop { + /// select! { + /// a = a_fut => total += a, + /// b = b_fut => total += b, + /// complete => break, + /// default => panic!(), // never runs (futures run first, then complete) + /// }; + /// } + /// assert_eq!(total, 10); + /// # }); + /// ``` + /// + /// Note that the futures that have been matched over can still be mutated + /// from inside the `select!` block's branches. This can be used to implement + /// more complex behavior such as timer resets or writing into the head of + /// a stream. + $select + }; + + ($select:item $select_biased:item) => { + document_select_macro!($select); + + /// Polls multiple futures and streams simultaneously, executing the branch + /// for the future that finishes first. Unlike [`select!`], if multiple futures are ready, + /// one will be selected in order of declaration. Futures directly + /// passed to `select_biased!` must be `Unpin` and implement `FusedFuture`. + /// + /// If an expression which yields a `Future` is passed to `select_biased!` + /// (e.g. an `async fn` call) instead of a `Future` by name the `Unpin` + /// requirement is relaxed, since the macro will pin the resulting `Future` + /// on the stack. However the `Future` returned by the expression must + /// still implement `FusedFuture`. + /// + /// Futures and streams which are not already fused can be fused using the + /// `.fuse()` method. Note, though, that fusing a future or stream directly + /// in the call to `select_biased!` will not be enough to prevent it from being + /// polled after completion if the `select_biased!` call is in a loop, so when + /// `select_biased!`ing in a loop, users should take care to `fuse()` outside of + /// the loop. + /// + /// `select_biased!` can be used as an expression and will return the return + /// value of the selected branch. For this reason the return type of every + /// branch in a `select_biased!` must be the same. + /// + /// This macro is only usable inside of async functions, closures, and blocks. + /// It is also gated behind the `async-await` feature of this library, which is + /// activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::select_biased; + /// let mut a = future::ready(4); + /// let mut b = future::pending::<()>(); + /// + /// let res = select_biased! { + /// a_res = a => a_res + 1, + /// _ = b => 0, + /// }; + /// assert_eq!(res, 5); + /// # }); + /// ``` + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt}; + /// use futures::select_biased; + /// let mut st = stream::iter(vec![2]).fuse(); + /// let mut fut = future::pending::<()>(); + /// + /// select_biased! { + /// x = st.next() => assert_eq!(Some(2), x), + /// _ = fut => panic!(), + /// }; + /// # }); + /// ``` + /// + /// As described earlier, `select_biased` can directly select on expressions + /// which return `Future`s - even if those do not implement `Unpin`: + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// use futures::select_biased; + /// + /// // Calling the following async fn returns a Future which does not + /// // implement Unpin + /// async fn async_identity_fn(arg: usize) -> usize { + /// arg + /// } + /// + /// let res = select_biased! { + /// a_res = async_identity_fn(62).fuse() => a_res + 1, + /// b_res = async_identity_fn(13).fuse() => b_res, + /// }; + /// assert!(res == 63 || res == 12); + /// # }); + /// ``` + /// + /// If a similar async function is called outside of `select_biased` to produce + /// a `Future`, the `Future` must be pinned in order to be able to pass + /// it to `select_biased`. This can be achieved via `Box::pin` for pinning a + /// `Future` on the heap or the `pin_mut!` macro for pinning a `Future` + /// on the stack. + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// use futures::select_biased; + /// use futures::pin_mut; + /// + /// // Calling the following async fn returns a Future which does not + /// // implement Unpin + /// async fn async_identity_fn(arg: usize) -> usize { + /// arg + /// } + /// + /// let fut_1 = async_identity_fn(1).fuse(); + /// let fut_2 = async_identity_fn(2).fuse(); + /// let mut fut_1 = Box::pin(fut_1); // Pins the Future on the heap + /// pin_mut!(fut_2); // Pins the Future on the stack + /// + /// let res = select_biased! { + /// a_res = fut_1 => a_res, + /// b_res = fut_2 => b_res, + /// }; + /// assert!(res == 1 || res == 2); + /// # }); + /// ``` + /// + /// `select_biased` also accepts a `complete` branch and a `default` branch. + /// `complete` will run if all futures and streams have already been + /// exhausted. `default` will run if no futures or streams are + /// immediately ready. `complete` takes priority over `default` in + /// the case where all futures have completed. + /// A motivating use-case for passing `Future`s by name as well as for + /// `complete` blocks is to call `select_biased!` in a loop, which is + /// demonstrated in the following example: + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::select_biased; + /// let mut a_fut = future::ready(4); + /// let mut b_fut = future::ready(6); + /// let mut total = 0; + /// + /// loop { + /// select_biased! { + /// a = a_fut => total += a, + /// b = b_fut => total += b, + /// complete => break, + /// default => panic!(), // never runs (futures run first, then complete) + /// }; + /// } + /// assert_eq!(total, 10); + /// # }); + /// ``` + /// + /// Note that the futures that have been matched over can still be mutated + /// from inside the `select_biased!` block's branches. This can be used to implement + /// more complex behavior such as timer resets or writing into the head of + /// a stream. + /// + /// [`select!`]: macro.select.html + $select_biased + }; +} + +#[cfg(feature = "std")] +#[allow(unreachable_pub)] +#[doc(hidden)] +pub use futures_macro::select_internal; + +#[allow(unreachable_pub)] +#[doc(hidden)] +pub use futures_macro::select_biased_internal; + +document_select_macro! { + #[cfg(feature = "std")] + #[macro_export] + macro_rules! select { + ($($tokens:tt)*) => {{ + use $crate::__private as __futures_crate; + $crate::select_internal! { + $( $tokens )* + } + }} + } + + #[macro_export] + macro_rules! select_biased { + ($($tokens:tt)*) => {{ + use $crate::__private as __futures_crate; + $crate::select_biased_internal! { + $( $tokens )* + } + }} + } +} diff --git a/third_party/rust/futures-util/src/async_await/stream_select_mod.rs b/third_party/rust/futures-util/src/async_await/stream_select_mod.rs new file mode 100644 index 0000000000..1c8002fff3 --- /dev/null +++ b/third_party/rust/futures-util/src/async_await/stream_select_mod.rs @@ -0,0 +1,40 @@ +//! The `stream_select` macro. + +#[cfg(feature = "std")] +#[allow(unreachable_pub)] +#[doc(hidden)] +pub use futures_macro::stream_select_internal; + +/// Combines several streams, all producing the same `Item` type, into one stream. +/// This is similar to `select_all` but does not require the streams to all be the same type. +/// It also keeps the streams inline, and does not require `Box<dyn Stream>`s to be allocated. +/// Streams passed to this macro must be `Unpin`. +/// +/// If multiple streams are ready, one will be pseudo randomly selected at runtime. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::{stream, StreamExt, stream_select}; +/// let endless_ints = |i| stream::iter(vec![i].into_iter().cycle()).fuse(); +/// +/// let mut endless_numbers = stream_select!(endless_ints(1i32), endless_ints(2), endless_ints(3)); +/// match endless_numbers.next().await { +/// Some(1) => println!("Got a 1"), +/// Some(2) => println!("Got a 2"), +/// Some(3) => println!("Got a 3"), +/// _ => unreachable!(), +/// } +/// # }); +/// ``` +#[cfg(feature = "std")] +#[macro_export] +macro_rules! stream_select { + ($($tokens:tt)*) => {{ + use $crate::__private as __futures_crate; + $crate::stream_select_internal! { + $( $tokens )* + } + }} +} diff --git a/third_party/rust/futures-util/src/compat/compat01as03.rs b/third_party/rust/futures-util/src/compat/compat01as03.rs new file mode 100644 index 0000000000..36de1da98d --- /dev/null +++ b/third_party/rust/futures-util/src/compat/compat01as03.rs @@ -0,0 +1,454 @@ +use futures_01::executor::{ + spawn as spawn01, Notify as Notify01, NotifyHandle as NotifyHandle01, Spawn as Spawn01, + UnsafeNotify as UnsafeNotify01, +}; +use futures_01::{Async as Async01, Future as Future01, Stream as Stream01}; +#[cfg(feature = "sink")] +use futures_01::{AsyncSink as AsyncSink01, Sink as Sink01}; +use futures_core::{future::Future as Future03, stream::Stream as Stream03, task as task03}; +#[cfg(feature = "sink")] +use futures_sink::Sink as Sink03; +use std::pin::Pin; +use std::task::Context; + +#[cfg(feature = "io-compat")] +#[cfg_attr(docsrs, doc(cfg(feature = "io-compat")))] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use io::{AsyncRead01CompatExt, AsyncWrite01CompatExt}; + +/// Converts a futures 0.1 Future, Stream, AsyncRead, or AsyncWrite +/// object to a futures 0.3-compatible version, +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Compat01As03<T> { + pub(crate) inner: Spawn01<T>, +} + +impl<T> Unpin for Compat01As03<T> {} + +impl<T> Compat01As03<T> { + /// Wraps a futures 0.1 Future, Stream, AsyncRead, or AsyncWrite + /// object in a futures 0.3-compatible wrapper. + pub fn new(object: T) -> Self { + Self { inner: spawn01(object) } + } + + fn in_notify<R>(&mut self, cx: &mut Context<'_>, f: impl FnOnce(&mut T) -> R) -> R { + let notify = &WakerToHandle(cx.waker()); + self.inner.poll_fn_notify(notify, 0, f) + } + + /// Get a reference to 0.1 Future, Stream, AsyncRead, or AsyncWrite object contained within. + pub fn get_ref(&self) -> &T { + self.inner.get_ref() + } + + /// Get a mutable reference to 0.1 Future, Stream, AsyncRead or AsyncWrite object contained + /// within. + pub fn get_mut(&mut self) -> &mut T { + self.inner.get_mut() + } + + /// Consume this wrapper to return the underlying 0.1 Future, Stream, AsyncRead, or + /// AsyncWrite object. + pub fn into_inner(self) -> T { + self.inner.into_inner() + } +} + +/// Extension trait for futures 0.1 [`Future`](futures_01::future::Future) +pub trait Future01CompatExt: Future01 { + /// Converts a futures 0.1 + /// [`Future<Item = T, Error = E>`](futures_01::future::Future) + /// into a futures 0.3 + /// [`Future<Output = Result<T, E>>`](futures_core::future::Future). + /// + /// ``` + /// # if cfg!(miri) { return; } // https://github.com/rust-lang/futures-rs/issues/2514 + /// # futures::executor::block_on(async { + /// # // TODO: These should be all using `futures::compat`, but that runs up against Cargo + /// # // feature issues + /// use futures_util::compat::Future01CompatExt; + /// + /// let future = futures_01::future::ok::<u32, ()>(1); + /// assert_eq!(future.compat().await, Ok(1)); + /// # }); + /// ``` + fn compat(self) -> Compat01As03<Self> + where + Self: Sized, + { + Compat01As03::new(self) + } +} +impl<Fut: Future01> Future01CompatExt for Fut {} + +/// Extension trait for futures 0.1 [`Stream`](futures_01::stream::Stream) +pub trait Stream01CompatExt: Stream01 { + /// Converts a futures 0.1 + /// [`Stream<Item = T, Error = E>`](futures_01::stream::Stream) + /// into a futures 0.3 + /// [`Stream<Item = Result<T, E>>`](futures_core::stream::Stream). + /// + /// ``` + /// # if cfg!(miri) { return; } // https://github.com/rust-lang/futures-rs/issues/2514 + /// # futures::executor::block_on(async { + /// use futures::stream::StreamExt; + /// use futures_util::compat::Stream01CompatExt; + /// + /// let stream = futures_01::stream::once::<u32, ()>(Ok(1)); + /// let mut stream = stream.compat(); + /// assert_eq!(stream.next().await, Some(Ok(1))); + /// assert_eq!(stream.next().await, None); + /// # }); + /// ``` + fn compat(self) -> Compat01As03<Self> + where + Self: Sized, + { + Compat01As03::new(self) + } +} +impl<St: Stream01> Stream01CompatExt for St {} + +/// Extension trait for futures 0.1 [`Sink`](futures_01::sink::Sink) +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub trait Sink01CompatExt: Sink01 { + /// Converts a futures 0.1 + /// [`Sink<SinkItem = T, SinkError = E>`](futures_01::sink::Sink) + /// into a futures 0.3 + /// [`Sink<T, Error = E>`](futures_sink::Sink). + /// + /// ``` + /// # if cfg!(miri) { return; } // https://github.com/rust-lang/futures-rs/issues/2514 + /// # futures::executor::block_on(async { + /// use futures::{sink::SinkExt, stream::StreamExt}; + /// use futures_util::compat::{Stream01CompatExt, Sink01CompatExt}; + /// + /// let (tx, rx) = futures_01::unsync::mpsc::channel(1); + /// let (mut tx, mut rx) = (tx.sink_compat(), rx.compat()); + /// + /// tx.send(1).await.unwrap(); + /// drop(tx); + /// assert_eq!(rx.next().await, Some(Ok(1))); + /// assert_eq!(rx.next().await, None); + /// # }); + /// ``` + fn sink_compat(self) -> Compat01As03Sink<Self, Self::SinkItem> + where + Self: Sized, + { + Compat01As03Sink::new(self) + } +} +#[cfg(feature = "sink")] +impl<Si: Sink01> Sink01CompatExt for Si {} + +fn poll_01_to_03<T, E>(x: Result<Async01<T>, E>) -> task03::Poll<Result<T, E>> { + match x? { + Async01::Ready(t) => task03::Poll::Ready(Ok(t)), + Async01::NotReady => task03::Poll::Pending, + } +} + +impl<Fut: Future01> Future03 for Compat01As03<Fut> { + type Output = Result<Fut::Item, Fut::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> task03::Poll<Self::Output> { + poll_01_to_03(self.in_notify(cx, Future01::poll)) + } +} + +impl<St: Stream01> Stream03 for Compat01As03<St> { + type Item = Result<St::Item, St::Error>; + + fn poll_next( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> task03::Poll<Option<Self::Item>> { + match self.in_notify(cx, Stream01::poll)? { + Async01::Ready(Some(t)) => task03::Poll::Ready(Some(Ok(t))), + Async01::Ready(None) => task03::Poll::Ready(None), + Async01::NotReady => task03::Poll::Pending, + } + } +} + +/// Converts a futures 0.1 Sink object to a futures 0.3-compatible version +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +#[derive(Debug)] +#[must_use = "sinks do nothing unless polled"] +pub struct Compat01As03Sink<S, SinkItem> { + pub(crate) inner: Spawn01<S>, + pub(crate) buffer: Option<SinkItem>, + pub(crate) close_started: bool, +} + +#[cfg(feature = "sink")] +impl<S, SinkItem> Unpin for Compat01As03Sink<S, SinkItem> {} + +#[cfg(feature = "sink")] +impl<S, SinkItem> Compat01As03Sink<S, SinkItem> { + /// Wraps a futures 0.1 Sink object in a futures 0.3-compatible wrapper. + pub fn new(inner: S) -> Self { + Self { inner: spawn01(inner), buffer: None, close_started: false } + } + + fn in_notify<R>(&mut self, cx: &mut Context<'_>, f: impl FnOnce(&mut S) -> R) -> R { + let notify = &WakerToHandle(cx.waker()); + self.inner.poll_fn_notify(notify, 0, f) + } + + /// Get a reference to 0.1 Sink object contained within. + pub fn get_ref(&self) -> &S { + self.inner.get_ref() + } + + /// Get a mutable reference to 0.1 Sink contained within. + pub fn get_mut(&mut self) -> &mut S { + self.inner.get_mut() + } + + /// Consume this wrapper to return the underlying 0.1 Sink. + pub fn into_inner(self) -> S { + self.inner.into_inner() + } +} + +#[cfg(feature = "sink")] +impl<S, SinkItem> Stream03 for Compat01As03Sink<S, SinkItem> +where + S: Stream01, +{ + type Item = Result<S::Item, S::Error>; + + fn poll_next( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> task03::Poll<Option<Self::Item>> { + match self.in_notify(cx, Stream01::poll)? { + Async01::Ready(Some(t)) => task03::Poll::Ready(Some(Ok(t))), + Async01::Ready(None) => task03::Poll::Ready(None), + Async01::NotReady => task03::Poll::Pending, + } + } +} + +#[cfg(feature = "sink")] +impl<S, SinkItem> Sink03<SinkItem> for Compat01As03Sink<S, SinkItem> +where + S: Sink01<SinkItem = SinkItem>, +{ + type Error = S::SinkError; + + fn start_send(mut self: Pin<&mut Self>, item: SinkItem) -> Result<(), Self::Error> { + debug_assert!(self.buffer.is_none()); + self.buffer = Some(item); + Ok(()) + } + + fn poll_ready( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> task03::Poll<Result<(), Self::Error>> { + match self.buffer.take() { + Some(item) => match self.in_notify(cx, |f| f.start_send(item))? { + AsyncSink01::Ready => task03::Poll::Ready(Ok(())), + AsyncSink01::NotReady(i) => { + self.buffer = Some(i); + task03::Poll::Pending + } + }, + None => task03::Poll::Ready(Ok(())), + } + } + + fn poll_flush( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> task03::Poll<Result<(), Self::Error>> { + let item = self.buffer.take(); + match self.in_notify(cx, |f| match item { + Some(i) => match f.start_send(i)? { + AsyncSink01::Ready => f.poll_complete().map(|i| (i, None)), + AsyncSink01::NotReady(t) => Ok((Async01::NotReady, Some(t))), + }, + None => f.poll_complete().map(|i| (i, None)), + })? { + (Async01::Ready(_), _) => task03::Poll::Ready(Ok(())), + (Async01::NotReady, item) => { + self.buffer = item; + task03::Poll::Pending + } + } + } + + fn poll_close( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> task03::Poll<Result<(), Self::Error>> { + let item = self.buffer.take(); + let close_started = self.close_started; + + let result = self.in_notify(cx, |f| { + if !close_started { + if let Some(item) = item { + if let AsyncSink01::NotReady(item) = f.start_send(item)? { + return Ok((Async01::NotReady, Some(item), false)); + } + } + + if let Async01::NotReady = f.poll_complete()? { + return Ok((Async01::NotReady, None, false)); + } + } + + Ok((<S as Sink01>::close(f)?, None, true)) + }); + + match result? { + (Async01::Ready(_), _, _) => task03::Poll::Ready(Ok(())), + (Async01::NotReady, item, close_started) => { + self.buffer = item; + self.close_started = close_started; + task03::Poll::Pending + } + } + } +} + +struct NotifyWaker(task03::Waker); + +#[allow(missing_debug_implementations)] // false positive: this is private type +#[derive(Clone)] +struct WakerToHandle<'a>(&'a task03::Waker); + +impl From<WakerToHandle<'_>> for NotifyHandle01 { + fn from(handle: WakerToHandle<'_>) -> Self { + let ptr = Box::new(NotifyWaker(handle.0.clone())); + + unsafe { Self::new(Box::into_raw(ptr)) } + } +} + +impl Notify01 for NotifyWaker { + fn notify(&self, _: usize) { + self.0.wake_by_ref(); + } +} + +unsafe impl UnsafeNotify01 for NotifyWaker { + unsafe fn clone_raw(&self) -> NotifyHandle01 { + WakerToHandle(&self.0).into() + } + + unsafe fn drop_raw(&self) { + let ptr: *const dyn UnsafeNotify01 = self; + drop(Box::from_raw(ptr as *mut dyn UnsafeNotify01)); + } +} + +#[cfg(feature = "io-compat")] +#[cfg_attr(docsrs, doc(cfg(feature = "io-compat")))] +mod io { + use super::*; + use futures_io::{AsyncRead as AsyncRead03, AsyncWrite as AsyncWrite03}; + use std::io::Error; + use tokio_io::{AsyncRead as AsyncRead01, AsyncWrite as AsyncWrite01}; + + /// Extension trait for tokio-io [`AsyncRead`](tokio_io::AsyncRead) + #[cfg_attr(docsrs, doc(cfg(feature = "io-compat")))] + pub trait AsyncRead01CompatExt: AsyncRead01 { + /// Converts a tokio-io [`AsyncRead`](tokio_io::AsyncRead) into a futures-io 0.3 + /// [`AsyncRead`](futures_io::AsyncRead). + /// + /// ``` + /// # if cfg!(miri) { return; } // https://github.com/rust-lang/futures-rs/issues/2514 + /// # futures::executor::block_on(async { + /// use futures::io::AsyncReadExt; + /// use futures_util::compat::AsyncRead01CompatExt; + /// + /// let input = b"Hello World!"; + /// let reader /* : impl tokio_io::AsyncRead */ = std::io::Cursor::new(input); + /// let mut reader /* : impl futures::io::AsyncRead + Unpin */ = reader.compat(); + /// + /// let mut output = Vec::with_capacity(12); + /// reader.read_to_end(&mut output).await.unwrap(); + /// assert_eq!(output, input); + /// # }); + /// ``` + fn compat(self) -> Compat01As03<Self> + where + Self: Sized, + { + Compat01As03::new(self) + } + } + impl<R: AsyncRead01> AsyncRead01CompatExt for R {} + + /// Extension trait for tokio-io [`AsyncWrite`](tokio_io::AsyncWrite) + #[cfg_attr(docsrs, doc(cfg(feature = "io-compat")))] + pub trait AsyncWrite01CompatExt: AsyncWrite01 { + /// Converts a tokio-io [`AsyncWrite`](tokio_io::AsyncWrite) into a futures-io 0.3 + /// [`AsyncWrite`](futures_io::AsyncWrite). + /// + /// ``` + /// # if cfg!(miri) { return; } // https://github.com/rust-lang/futures-rs/issues/2514 + /// # futures::executor::block_on(async { + /// use futures::io::AsyncWriteExt; + /// use futures_util::compat::AsyncWrite01CompatExt; + /// + /// let input = b"Hello World!"; + /// let mut cursor = std::io::Cursor::new(Vec::with_capacity(12)); + /// + /// let mut writer = (&mut cursor).compat(); + /// writer.write_all(input).await.unwrap(); + /// + /// assert_eq!(cursor.into_inner(), input); + /// # }); + /// ``` + fn compat(self) -> Compat01As03<Self> + where + Self: Sized, + { + Compat01As03::new(self) + } + } + impl<W: AsyncWrite01> AsyncWrite01CompatExt for W {} + + impl<R: AsyncRead01> AsyncRead03 for Compat01As03<R> { + fn poll_read( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &mut [u8], + ) -> task03::Poll<Result<usize, Error>> { + poll_01_to_03(self.in_notify(cx, |x| x.poll_read(buf))) + } + } + + impl<W: AsyncWrite01> AsyncWrite03 for Compat01As03<W> { + fn poll_write( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &[u8], + ) -> task03::Poll<Result<usize, Error>> { + poll_01_to_03(self.in_notify(cx, |x| x.poll_write(buf))) + } + + fn poll_flush( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> task03::Poll<Result<(), Error>> { + poll_01_to_03(self.in_notify(cx, AsyncWrite01::poll_flush)) + } + + fn poll_close( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> task03::Poll<Result<(), Error>> { + poll_01_to_03(self.in_notify(cx, AsyncWrite01::shutdown)) + } + } +} diff --git a/third_party/rust/futures-util/src/compat/compat03as01.rs b/third_party/rust/futures-util/src/compat/compat03as01.rs new file mode 100644 index 0000000000..5d3a6e920b --- /dev/null +++ b/third_party/rust/futures-util/src/compat/compat03as01.rs @@ -0,0 +1,265 @@ +use crate::task::{self as task03, ArcWake as ArcWake03, WakerRef}; +use futures_01::{ + task as task01, Async as Async01, Future as Future01, Poll as Poll01, Stream as Stream01, +}; +#[cfg(feature = "sink")] +use futures_01::{AsyncSink as AsyncSink01, Sink as Sink01, StartSend as StartSend01}; +use futures_core::{ + future::TryFuture as TryFuture03, + stream::TryStream as TryStream03, + task::{RawWaker, RawWakerVTable}, +}; +#[cfg(feature = "sink")] +use futures_sink::Sink as Sink03; +#[cfg(feature = "sink")] +use std::marker::PhantomData; +use std::{mem, pin::Pin, sync::Arc, task::Context}; + +/// Converts a futures 0.3 [`TryFuture`](futures_core::future::TryFuture) or +/// [`TryStream`](futures_core::stream::TryStream) into a futures 0.1 +/// [`Future`](futures_01::future::Future) or +/// [`Stream`](futures_01::stream::Stream). +#[derive(Debug, Clone, Copy)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Compat<T> { + pub(crate) inner: T, +} + +/// Converts a futures 0.3 [`Sink`](futures_sink::Sink) into a futures 0.1 +/// [`Sink`](futures_01::sink::Sink). +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +#[derive(Debug)] +#[must_use = "sinks do nothing unless polled"] +pub struct CompatSink<T, Item> { + inner: T, + _phantom: PhantomData<fn(Item)>, +} + +impl<T> Compat<T> { + /// Creates a new [`Compat`]. + /// + /// For types which implement appropriate futures `0.3` + /// traits, the result will be a type which implements + /// the corresponding futures 0.1 type. + pub fn new(inner: T) -> Self { + Self { inner } + } + + /// Get a reference to 0.3 Future, Stream, AsyncRead, or AsyncWrite object + /// contained within. + pub fn get_ref(&self) -> &T { + &self.inner + } + + /// Get a mutable reference to 0.3 Future, Stream, AsyncRead, or AsyncWrite object + /// contained within. + pub fn get_mut(&mut self) -> &mut T { + &mut self.inner + } + + /// Returns the inner item. + pub fn into_inner(self) -> T { + self.inner + } +} + +#[cfg(feature = "sink")] +impl<T, Item> CompatSink<T, Item> { + /// Creates a new [`CompatSink`]. + pub fn new(inner: T) -> Self { + Self { inner, _phantom: PhantomData } + } + + /// Get a reference to 0.3 Sink contained within. + pub fn get_ref(&self) -> &T { + &self.inner + } + + /// Get a mutable reference to 0.3 Sink contained within. + pub fn get_mut(&mut self) -> &mut T { + &mut self.inner + } + + /// Returns the inner item. + pub fn into_inner(self) -> T { + self.inner + } +} + +fn poll_03_to_01<T, E>(x: task03::Poll<Result<T, E>>) -> Result<Async01<T>, E> { + match x? { + task03::Poll::Ready(t) => Ok(Async01::Ready(t)), + task03::Poll::Pending => Ok(Async01::NotReady), + } +} + +impl<Fut> Future01 for Compat<Fut> +where + Fut: TryFuture03 + Unpin, +{ + type Item = Fut::Ok; + type Error = Fut::Error; + + fn poll(&mut self) -> Poll01<Self::Item, Self::Error> { + with_context(self, |inner, cx| poll_03_to_01(inner.try_poll(cx))) + } +} + +impl<St> Stream01 for Compat<St> +where + St: TryStream03 + Unpin, +{ + type Item = St::Ok; + type Error = St::Error; + + fn poll(&mut self) -> Poll01<Option<Self::Item>, Self::Error> { + with_context(self, |inner, cx| match inner.try_poll_next(cx)? { + task03::Poll::Ready(None) => Ok(Async01::Ready(None)), + task03::Poll::Ready(Some(t)) => Ok(Async01::Ready(Some(t))), + task03::Poll::Pending => Ok(Async01::NotReady), + }) + } +} + +#[cfg(feature = "sink")] +impl<T, Item> Sink01 for CompatSink<T, Item> +where + T: Sink03<Item> + Unpin, +{ + type SinkItem = Item; + type SinkError = T::Error; + + fn start_send(&mut self, item: Self::SinkItem) -> StartSend01<Self::SinkItem, Self::SinkError> { + with_sink_context(self, |mut inner, cx| match inner.as_mut().poll_ready(cx)? { + task03::Poll::Ready(()) => inner.start_send(item).map(|()| AsyncSink01::Ready), + task03::Poll::Pending => Ok(AsyncSink01::NotReady(item)), + }) + } + + fn poll_complete(&mut self) -> Poll01<(), Self::SinkError> { + with_sink_context(self, |inner, cx| poll_03_to_01(inner.poll_flush(cx))) + } + + fn close(&mut self) -> Poll01<(), Self::SinkError> { + with_sink_context(self, |inner, cx| poll_03_to_01(inner.poll_close(cx))) + } +} + +#[derive(Clone)] +struct Current(task01::Task); + +impl Current { + fn new() -> Self { + Self(task01::current()) + } + + fn as_waker(&self) -> WakerRef<'_> { + unsafe fn ptr_to_current<'a>(ptr: *const ()) -> &'a Current { + &*(ptr as *const Current) + } + fn current_to_ptr(current: &Current) -> *const () { + current as *const Current as *const () + } + + unsafe fn clone(ptr: *const ()) -> RawWaker { + // Lazily create the `Arc` only when the waker is actually cloned. + // FIXME: remove `transmute` when a `Waker` -> `RawWaker` conversion + // function is landed in `core`. + mem::transmute::<task03::Waker, RawWaker>(task03::waker(Arc::new( + ptr_to_current(ptr).clone(), + ))) + } + unsafe fn drop(_: *const ()) {} + unsafe fn wake(ptr: *const ()) { + ptr_to_current(ptr).0.notify() + } + + let ptr = current_to_ptr(self); + let vtable = &RawWakerVTable::new(clone, wake, wake, drop); + WakerRef::new_unowned(std::mem::ManuallyDrop::new(unsafe { + task03::Waker::from_raw(RawWaker::new(ptr, vtable)) + })) + } +} + +impl ArcWake03 for Current { + fn wake_by_ref(arc_self: &Arc<Self>) { + arc_self.0.notify(); + } +} + +fn with_context<T, R, F>(compat: &mut Compat<T>, f: F) -> R +where + T: Unpin, + F: FnOnce(Pin<&mut T>, &mut Context<'_>) -> R, +{ + let current = Current::new(); + let waker = current.as_waker(); + let mut cx = Context::from_waker(&waker); + f(Pin::new(&mut compat.inner), &mut cx) +} + +#[cfg(feature = "sink")] +fn with_sink_context<T, Item, R, F>(compat: &mut CompatSink<T, Item>, f: F) -> R +where + T: Unpin, + F: FnOnce(Pin<&mut T>, &mut Context<'_>) -> R, +{ + let current = Current::new(); + let waker = current.as_waker(); + let mut cx = Context::from_waker(&waker); + f(Pin::new(&mut compat.inner), &mut cx) +} + +#[cfg(feature = "io-compat")] +#[cfg_attr(docsrs, doc(cfg(feature = "io-compat")))] +mod io { + use super::*; + use futures_io::{AsyncRead as AsyncRead03, AsyncWrite as AsyncWrite03}; + use tokio_io::{AsyncRead as AsyncRead01, AsyncWrite as AsyncWrite01}; + + fn poll_03_to_io<T>(x: task03::Poll<Result<T, std::io::Error>>) -> Result<T, std::io::Error> { + match x { + task03::Poll::Ready(Ok(t)) => Ok(t), + task03::Poll::Pending => Err(std::io::ErrorKind::WouldBlock.into()), + task03::Poll::Ready(Err(e)) => Err(e), + } + } + + impl<R: AsyncRead03 + Unpin> std::io::Read for Compat<R> { + fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> { + let current = Current::new(); + let waker = current.as_waker(); + let mut cx = Context::from_waker(&waker); + poll_03_to_io(Pin::new(&mut self.inner).poll_read(&mut cx, buf)) + } + } + + impl<R: AsyncRead03 + Unpin> AsyncRead01 for Compat<R> {} + + impl<W: AsyncWrite03 + Unpin> std::io::Write for Compat<W> { + fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> { + let current = Current::new(); + let waker = current.as_waker(); + let mut cx = Context::from_waker(&waker); + poll_03_to_io(Pin::new(&mut self.inner).poll_write(&mut cx, buf)) + } + + fn flush(&mut self) -> std::io::Result<()> { + let current = Current::new(); + let waker = current.as_waker(); + let mut cx = Context::from_waker(&waker); + poll_03_to_io(Pin::new(&mut self.inner).poll_flush(&mut cx)) + } + } + + impl<W: AsyncWrite03 + Unpin> AsyncWrite01 for Compat<W> { + fn shutdown(&mut self) -> std::io::Result<Async01<()>> { + let current = Current::new(); + let waker = current.as_waker(); + let mut cx = Context::from_waker(&waker); + poll_03_to_01(Pin::new(&mut self.inner).poll_close(&mut cx)) + } + } +} diff --git a/third_party/rust/futures-util/src/compat/executor.rs b/third_party/rust/futures-util/src/compat/executor.rs new file mode 100644 index 0000000000..ea0c67a0ae --- /dev/null +++ b/third_party/rust/futures-util/src/compat/executor.rs @@ -0,0 +1,86 @@ +use super::{Compat, Future01CompatExt}; +use crate::{ + future::{FutureExt, TryFutureExt, UnitError}, + task::SpawnExt, +}; +use futures_01::future::{ExecuteError as ExecuteError01, Executor as Executor01}; +use futures_01::Future as Future01; +use futures_task::{FutureObj, Spawn as Spawn03, SpawnError as SpawnError03}; + +/// A future that can run on a futures 0.1 +/// [`Executor`](futures_01::future::Executor). +pub type Executor01Future = Compat<UnitError<FutureObj<'static, ()>>>; + +/// Extension trait for futures 0.1 [`Executor`](futures_01::future::Executor). +pub trait Executor01CompatExt: Executor01<Executor01Future> + Clone + Send + 'static { + /// Converts a futures 0.1 [`Executor`](futures_01::future::Executor) into a + /// futures 0.3 [`Spawn`](futures_task::Spawn). + /// + /// ``` + /// # if cfg!(miri) { return; } // Miri does not support epoll + /// use futures::task::SpawnExt; + /// use futures::future::{FutureExt, TryFutureExt}; + /// use futures_util::compat::Executor01CompatExt; + /// use tokio::executor::DefaultExecutor; + /// + /// # let (tx, rx) = futures::channel::oneshot::channel(); + /// + /// let spawner = DefaultExecutor::current().compat(); + /// let future03 = async move { + /// println!("Running on the pool"); + /// spawner.spawn(async { + /// println!("Spawned!"); + /// # tx.send(42).unwrap(); + /// }).unwrap(); + /// }; + /// + /// let future01 = future03.unit_error().boxed().compat(); + /// + /// tokio::run(future01); + /// # futures::executor::block_on(rx).unwrap(); + /// ``` + fn compat(self) -> Executor01As03<Self> + where + Self: Sized; +} + +impl<Ex> Executor01CompatExt for Ex +where + Ex: Executor01<Executor01Future> + Clone + Send + 'static, +{ + fn compat(self) -> Executor01As03<Self> { + Executor01As03 { executor01: self } + } +} + +/// Converts a futures 0.1 [`Executor`](futures_01::future::Executor) into a +/// futures 0.3 [`Spawn`](futures_task::Spawn). +#[derive(Debug, Clone)] +pub struct Executor01As03<Ex> { + executor01: Ex, +} + +impl<Ex> Spawn03 for Executor01As03<Ex> +where + Ex: Executor01<Executor01Future> + Clone + Send + 'static, +{ + fn spawn_obj(&self, future: FutureObj<'static, ()>) -> Result<(), SpawnError03> { + let future = future.unit_error().compat(); + + self.executor01.execute(future).map_err(|_| SpawnError03::shutdown()) + } +} + +#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 +impl<Sp, Fut> Executor01<Fut> for Compat<Sp> +where + for<'a> &'a Sp: Spawn03, + Fut: Future01<Item = (), Error = ()> + Send + 'static, +{ + fn execute(&self, future: Fut) -> Result<(), ExecuteError01<Fut>> { + (&self.inner) + .spawn(future.compat().map(|_| ())) + .expect("unable to spawn future from Compat executor"); + Ok(()) + } +} diff --git a/third_party/rust/futures-util/src/compat/mod.rs b/third_party/rust/futures-util/src/compat/mod.rs new file mode 100644 index 0000000000..4812803eb6 --- /dev/null +++ b/third_party/rust/futures-util/src/compat/mod.rs @@ -0,0 +1,22 @@ +//! Interop between `futures` 0.1 and 0.3. +//! +//! This module is only available when the `compat` feature of this +//! library is activated. + +mod executor; +pub use self::executor::{Executor01As03, Executor01CompatExt, Executor01Future}; + +mod compat01as03; +#[cfg(feature = "io-compat")] +#[cfg_attr(docsrs, doc(cfg(feature = "io-compat")))] +pub use self::compat01as03::{AsyncRead01CompatExt, AsyncWrite01CompatExt}; +pub use self::compat01as03::{Compat01As03, Future01CompatExt, Stream01CompatExt}; +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub use self::compat01as03::{Compat01As03Sink, Sink01CompatExt}; + +mod compat03as01; +pub use self::compat03as01::Compat; +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub use self::compat03as01::CompatSink; diff --git a/third_party/rust/futures-util/src/fns.rs b/third_party/rust/futures-util/src/fns.rs new file mode 100644 index 0000000000..37ee03e6df --- /dev/null +++ b/third_party/rust/futures-util/src/fns.rs @@ -0,0 +1,372 @@ +use core::fmt::{self, Debug}; +use core::marker::PhantomData; + +pub trait FnOnce1<A> { + type Output; + fn call_once(self, arg: A) -> Self::Output; +} + +impl<T, A, R> FnOnce1<A> for T +where + T: FnOnce(A) -> R, +{ + type Output = R; + fn call_once(self, arg: A) -> R { + self(arg) + } +} + +pub trait FnMut1<A>: FnOnce1<A> { + fn call_mut(&mut self, arg: A) -> Self::Output; +} + +impl<T, A, R> FnMut1<A> for T +where + T: FnMut(A) -> R, +{ + fn call_mut(&mut self, arg: A) -> R { + self(arg) + } +} + +// Not used, but present for completeness +#[allow(unreachable_pub)] +pub trait Fn1<A>: FnMut1<A> { + fn call(&self, arg: A) -> Self::Output; +} + +impl<T, A, R> Fn1<A> for T +where + T: Fn(A) -> R, +{ + fn call(&self, arg: A) -> R { + self(arg) + } +} + +macro_rules! trivial_fn_impls { + ($name:ident <$($arg:ident),*> $t:ty = $debug:literal) => { + impl<$($arg),*> Copy for $t {} + impl<$($arg),*> Clone for $t { + fn clone(&self) -> Self { *self } + } + impl<$($arg),*> Debug for $t { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str($debug) + } + } + impl<$($arg,)* A> FnMut1<A> for $t where Self: FnOnce1<A> { + fn call_mut(&mut self, arg: A) -> Self::Output { + self.call_once(arg) + } + } + impl<$($arg,)* A> Fn1<A> for $t where Self: FnOnce1<A> { + fn call(&self, arg: A) -> Self::Output { + self.call_once(arg) + } + } + pub(crate) fn $name<$($arg),*>() -> $t { + Default::default() + } + } +} + +pub struct OkFn<E>(PhantomData<fn(E)>); + +impl<E> Default for OkFn<E> { + fn default() -> Self { + Self(PhantomData) + } +} + +impl<A, E> FnOnce1<A> for OkFn<E> { + type Output = Result<A, E>; + fn call_once(self, arg: A) -> Self::Output { + Ok(arg) + } +} + +trivial_fn_impls!(ok_fn <T> OkFn<T> = "Ok"); + +#[derive(Debug, Copy, Clone, Default)] +pub struct ChainFn<F, G>(F, G); + +impl<F, G, A> FnOnce1<A> for ChainFn<F, G> +where + F: FnOnce1<A>, + G: FnOnce1<F::Output>, +{ + type Output = G::Output; + fn call_once(self, arg: A) -> Self::Output { + self.1.call_once(self.0.call_once(arg)) + } +} +impl<F, G, A> FnMut1<A> for ChainFn<F, G> +where + F: FnMut1<A>, + G: FnMut1<F::Output>, +{ + fn call_mut(&mut self, arg: A) -> Self::Output { + self.1.call_mut(self.0.call_mut(arg)) + } +} +impl<F, G, A> Fn1<A> for ChainFn<F, G> +where + F: Fn1<A>, + G: Fn1<F::Output>, +{ + fn call(&self, arg: A) -> Self::Output { + self.1.call(self.0.call(arg)) + } +} +pub(crate) fn chain_fn<F, G>(f: F, g: G) -> ChainFn<F, G> { + ChainFn(f, g) +} + +#[derive(Default)] +pub struct MergeResultFn; + +impl<T> FnOnce1<Result<T, T>> for MergeResultFn { + type Output = T; + fn call_once(self, arg: Result<T, T>) -> Self::Output { + match arg { + Ok(x) => x, + Err(x) => x, + } + } +} +trivial_fn_impls!(merge_result_fn <> MergeResultFn = "merge_result"); + +#[derive(Debug, Copy, Clone, Default)] +pub struct InspectFn<F>(F); + +#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 +impl<F, A> FnOnce1<A> for InspectFn<F> +where + F: for<'a> FnOnce1<&'a A, Output = ()>, +{ + type Output = A; + fn call_once(self, arg: A) -> Self::Output { + self.0.call_once(&arg); + arg + } +} +#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 +impl<F, A> FnMut1<A> for InspectFn<F> +where + F: for<'a> FnMut1<&'a A, Output = ()>, +{ + fn call_mut(&mut self, arg: A) -> Self::Output { + self.0.call_mut(&arg); + arg + } +} +#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 +impl<F, A> Fn1<A> for InspectFn<F> +where + F: for<'a> Fn1<&'a A, Output = ()>, +{ + fn call(&self, arg: A) -> Self::Output { + self.0.call(&arg); + arg + } +} +pub(crate) fn inspect_fn<F>(f: F) -> InspectFn<F> { + InspectFn(f) +} + +#[derive(Debug, Copy, Clone, Default)] +pub struct MapOkFn<F>(F); + +impl<F, T, E> FnOnce1<Result<T, E>> for MapOkFn<F> +where + F: FnOnce1<T>, +{ + type Output = Result<F::Output, E>; + fn call_once(self, arg: Result<T, E>) -> Self::Output { + arg.map(|x| self.0.call_once(x)) + } +} +impl<F, T, E> FnMut1<Result<T, E>> for MapOkFn<F> +where + F: FnMut1<T>, +{ + fn call_mut(&mut self, arg: Result<T, E>) -> Self::Output { + arg.map(|x| self.0.call_mut(x)) + } +} +impl<F, T, E> Fn1<Result<T, E>> for MapOkFn<F> +where + F: Fn1<T>, +{ + fn call(&self, arg: Result<T, E>) -> Self::Output { + arg.map(|x| self.0.call(x)) + } +} +pub(crate) fn map_ok_fn<F>(f: F) -> MapOkFn<F> { + MapOkFn(f) +} + +#[derive(Debug, Copy, Clone, Default)] +pub struct MapErrFn<F>(F); + +impl<F, T, E> FnOnce1<Result<T, E>> for MapErrFn<F> +where + F: FnOnce1<E>, +{ + type Output = Result<T, F::Output>; + fn call_once(self, arg: Result<T, E>) -> Self::Output { + arg.map_err(|x| self.0.call_once(x)) + } +} +impl<F, T, E> FnMut1<Result<T, E>> for MapErrFn<F> +where + F: FnMut1<E>, +{ + fn call_mut(&mut self, arg: Result<T, E>) -> Self::Output { + arg.map_err(|x| self.0.call_mut(x)) + } +} +impl<F, T, E> Fn1<Result<T, E>> for MapErrFn<F> +where + F: Fn1<E>, +{ + fn call(&self, arg: Result<T, E>) -> Self::Output { + arg.map_err(|x| self.0.call(x)) + } +} +pub(crate) fn map_err_fn<F>(f: F) -> MapErrFn<F> { + MapErrFn(f) +} + +#[derive(Debug, Copy, Clone)] +pub struct InspectOkFn<F>(F); + +impl<'a, F, T, E> FnOnce1<&'a Result<T, E>> for InspectOkFn<F> +where + F: FnOnce1<&'a T, Output = ()>, +{ + type Output = (); + fn call_once(self, arg: &'a Result<T, E>) -> Self::Output { + if let Ok(x) = arg { + self.0.call_once(x) + } + } +} +impl<'a, F, T, E> FnMut1<&'a Result<T, E>> for InspectOkFn<F> +where + F: FnMut1<&'a T, Output = ()>, +{ + fn call_mut(&mut self, arg: &'a Result<T, E>) -> Self::Output { + if let Ok(x) = arg { + self.0.call_mut(x) + } + } +} +impl<'a, F, T, E> Fn1<&'a Result<T, E>> for InspectOkFn<F> +where + F: Fn1<&'a T, Output = ()>, +{ + fn call(&self, arg: &'a Result<T, E>) -> Self::Output { + if let Ok(x) = arg { + self.0.call(x) + } + } +} +pub(crate) fn inspect_ok_fn<F>(f: F) -> InspectOkFn<F> { + InspectOkFn(f) +} + +#[derive(Debug, Copy, Clone)] +pub struct InspectErrFn<F>(F); + +impl<'a, F, T, E> FnOnce1<&'a Result<T, E>> for InspectErrFn<F> +where + F: FnOnce1<&'a E, Output = ()>, +{ + type Output = (); + fn call_once(self, arg: &'a Result<T, E>) -> Self::Output { + if let Err(x) = arg { + self.0.call_once(x) + } + } +} +impl<'a, F, T, E> FnMut1<&'a Result<T, E>> for InspectErrFn<F> +where + F: FnMut1<&'a E, Output = ()>, +{ + fn call_mut(&mut self, arg: &'a Result<T, E>) -> Self::Output { + if let Err(x) = arg { + self.0.call_mut(x) + } + } +} +impl<'a, F, T, E> Fn1<&'a Result<T, E>> for InspectErrFn<F> +where + F: Fn1<&'a E, Output = ()>, +{ + fn call(&self, arg: &'a Result<T, E>) -> Self::Output { + if let Err(x) = arg { + self.0.call(x) + } + } +} +pub(crate) fn inspect_err_fn<F>(f: F) -> InspectErrFn<F> { + InspectErrFn(f) +} + +pub(crate) type MapOkOrElseFn<F, G> = ChainFn<MapOkFn<F>, ChainFn<MapErrFn<G>, MergeResultFn>>; +pub(crate) fn map_ok_or_else_fn<F, G>(f: F, g: G) -> MapOkOrElseFn<F, G> { + chain_fn(map_ok_fn(f), chain_fn(map_err_fn(g), merge_result_fn())) +} + +#[derive(Debug, Copy, Clone, Default)] +pub struct UnwrapOrElseFn<F>(F); + +impl<F, T, E> FnOnce1<Result<T, E>> for UnwrapOrElseFn<F> +where + F: FnOnce1<E, Output = T>, +{ + type Output = T; + fn call_once(self, arg: Result<T, E>) -> Self::Output { + arg.unwrap_or_else(|x| self.0.call_once(x)) + } +} +impl<F, T, E> FnMut1<Result<T, E>> for UnwrapOrElseFn<F> +where + F: FnMut1<E, Output = T>, +{ + fn call_mut(&mut self, arg: Result<T, E>) -> Self::Output { + arg.unwrap_or_else(|x| self.0.call_mut(x)) + } +} +impl<F, T, E> Fn1<Result<T, E>> for UnwrapOrElseFn<F> +where + F: Fn1<E, Output = T>, +{ + fn call(&self, arg: Result<T, E>) -> Self::Output { + arg.unwrap_or_else(|x| self.0.call(x)) + } +} +pub(crate) fn unwrap_or_else_fn<F>(f: F) -> UnwrapOrElseFn<F> { + UnwrapOrElseFn(f) +} + +pub struct IntoFn<T>(PhantomData<fn() -> T>); + +impl<T> Default for IntoFn<T> { + fn default() -> Self { + Self(PhantomData) + } +} +impl<A, T> FnOnce1<A> for IntoFn<T> +where + A: Into<T>, +{ + type Output = T; + fn call_once(self, arg: A) -> Self::Output { + arg.into() + } +} + +trivial_fn_impls!(into_fn <T> IntoFn<T> = "Into::into"); diff --git a/third_party/rust/futures-util/src/future/abortable.rs b/third_party/rust/futures-util/src/future/abortable.rs new file mode 100644 index 0000000000..d017ab7340 --- /dev/null +++ b/third_party/rust/futures-util/src/future/abortable.rs @@ -0,0 +1,19 @@ +use super::assert_future; +use crate::future::{AbortHandle, Abortable, Aborted}; +use futures_core::future::Future; + +/// Creates a new `Abortable` future and an `AbortHandle` which can be used to stop it. +/// +/// This function is a convenient (but less flexible) alternative to calling +/// `AbortHandle::new` and `Abortable::new` manually. +/// +/// This function is only available when the `std` or `alloc` feature of this +/// library is activated, and it is activated by default. +pub fn abortable<Fut>(future: Fut) -> (Abortable<Fut>, AbortHandle) +where + Fut: Future, +{ + let (handle, reg) = AbortHandle::new_pair(); + let abortable = assert_future::<Result<Fut::Output, Aborted>, _>(Abortable::new(future, reg)); + (abortable, handle) +} diff --git a/third_party/rust/futures-util/src/future/either.rs b/third_party/rust/futures-util/src/future/either.rs new file mode 100644 index 0000000000..27e5064dfb --- /dev/null +++ b/third_party/rust/futures-util/src/future/either.rs @@ -0,0 +1,317 @@ +use core::pin::Pin; +use core::task::{Context, Poll}; +use futures_core::future::{FusedFuture, Future}; +use futures_core::stream::{FusedStream, Stream}; +#[cfg(feature = "sink")] +use futures_sink::Sink; + +/// Combines two different futures, streams, or sinks having the same associated types into a single type. +/// +/// This is useful when conditionally choosing between two distinct future types: +/// +/// ```rust +/// use futures::future::Either; +/// +/// # futures::executor::block_on(async { +/// let cond = true; +/// +/// let fut = if cond { +/// Either::Left(async move { 12 }) +/// } else { +/// Either::Right(async move { 44 }) +/// }; +/// +/// assert_eq!(fut.await, 12); +/// # }) +/// ``` +#[derive(Debug, Clone)] +pub enum Either<A, B> { + /// First branch of the type + Left(/* #[pin] */ A), + /// Second branch of the type + Right(/* #[pin] */ B), +} + +impl<A, B> Either<A, B> { + /// Convert `Pin<&Either<A, B>>` to `Either<Pin<&A>, Pin<&B>>`, + /// pinned projections of the inner variants. + pub fn as_pin_ref(self: Pin<&Self>) -> Either<Pin<&A>, Pin<&B>> { + // SAFETY: We can use `new_unchecked` because the `inner` parts are + // guaranteed to be pinned, as they come from `self` which is pinned. + unsafe { + match *Pin::get_ref(self) { + Either::Left(ref inner) => Either::Left(Pin::new_unchecked(inner)), + Either::Right(ref inner) => Either::Right(Pin::new_unchecked(inner)), + } + } + } + + /// Convert `Pin<&mut Either<A, B>>` to `Either<Pin<&mut A>, Pin<&mut B>>`, + /// pinned projections of the inner variants. + pub fn as_pin_mut(self: Pin<&mut Self>) -> Either<Pin<&mut A>, Pin<&mut B>> { + // SAFETY: `get_unchecked_mut` is fine because we don't move anything. + // We can use `new_unchecked` because the `inner` parts are guaranteed + // to be pinned, as they come from `self` which is pinned, and we never + // offer an unpinned `&mut A` or `&mut B` through `Pin<&mut Self>`. We + // also don't have an implementation of `Drop`, nor manual `Unpin`. + unsafe { + match *Pin::get_unchecked_mut(self) { + Either::Left(ref mut inner) => Either::Left(Pin::new_unchecked(inner)), + Either::Right(ref mut inner) => Either::Right(Pin::new_unchecked(inner)), + } + } + } +} + +impl<A, B, T> Either<(T, A), (T, B)> { + /// Factor out a homogeneous type from an either of pairs. + /// + /// Here, the homogeneous type is the first element of the pairs. + pub fn factor_first(self) -> (T, Either<A, B>) { + match self { + Either::Left((x, a)) => (x, Either::Left(a)), + Either::Right((x, b)) => (x, Either::Right(b)), + } + } +} + +impl<A, B, T> Either<(A, T), (B, T)> { + /// Factor out a homogeneous type from an either of pairs. + /// + /// Here, the homogeneous type is the second element of the pairs. + pub fn factor_second(self) -> (Either<A, B>, T) { + match self { + Either::Left((a, x)) => (Either::Left(a), x), + Either::Right((b, x)) => (Either::Right(b), x), + } + } +} + +impl<T> Either<T, T> { + /// Extract the value of an either over two equivalent types. + pub fn into_inner(self) -> T { + match self { + Either::Left(x) => x, + Either::Right(x) => x, + } + } +} + +impl<A, B> Future for Either<A, B> +where + A: Future, + B: Future<Output = A::Output>, +{ + type Output = A::Output; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + match self.as_pin_mut() { + Either::Left(x) => x.poll(cx), + Either::Right(x) => x.poll(cx), + } + } +} + +impl<A, B> FusedFuture for Either<A, B> +where + A: FusedFuture, + B: FusedFuture<Output = A::Output>, +{ + fn is_terminated(&self) -> bool { + match self { + Either::Left(x) => x.is_terminated(), + Either::Right(x) => x.is_terminated(), + } + } +} + +impl<A, B> Stream for Either<A, B> +where + A: Stream, + B: Stream<Item = A::Item>, +{ + type Item = A::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_next(cx), + Either::Right(x) => x.poll_next(cx), + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + match self { + Either::Left(x) => x.size_hint(), + Either::Right(x) => x.size_hint(), + } + } +} + +impl<A, B> FusedStream for Either<A, B> +where + A: FusedStream, + B: FusedStream<Item = A::Item>, +{ + fn is_terminated(&self) -> bool { + match self { + Either::Left(x) => x.is_terminated(), + Either::Right(x) => x.is_terminated(), + } + } +} + +#[cfg(feature = "sink")] +impl<A, B, Item> Sink<Item> for Either<A, B> +where + A: Sink<Item>, + B: Sink<Item, Error = A::Error>, +{ + type Error = A::Error; + + fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_ready(cx), + Either::Right(x) => x.poll_ready(cx), + } + } + + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + match self.as_pin_mut() { + Either::Left(x) => x.start_send(item), + Either::Right(x) => x.start_send(item), + } + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_flush(cx), + Either::Right(x) => x.poll_flush(cx), + } + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_close(cx), + Either::Right(x) => x.poll_close(cx), + } + } +} + +#[cfg(feature = "io")] +#[cfg(feature = "std")] +mod if_std { + use super::*; + + use core::pin::Pin; + use core::task::{Context, Poll}; + use futures_io::{ + AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, IoSlice, IoSliceMut, Result, SeekFrom, + }; + + impl<A, B> AsyncRead for Either<A, B> + where + A: AsyncRead, + B: AsyncRead, + { + fn poll_read( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &mut [u8], + ) -> Poll<Result<usize>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_read(cx, buf), + Either::Right(x) => x.poll_read(cx, buf), + } + } + + fn poll_read_vectored( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &mut [IoSliceMut<'_>], + ) -> Poll<Result<usize>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_read_vectored(cx, bufs), + Either::Right(x) => x.poll_read_vectored(cx, bufs), + } + } + } + + impl<A, B> AsyncWrite for Either<A, B> + where + A: AsyncWrite, + B: AsyncWrite, + { + fn poll_write( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &[u8], + ) -> Poll<Result<usize>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_write(cx, buf), + Either::Right(x) => x.poll_write(cx, buf), + } + } + + fn poll_write_vectored( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<Result<usize>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_write_vectored(cx, bufs), + Either::Right(x) => x.poll_write_vectored(cx, bufs), + } + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_flush(cx), + Either::Right(x) => x.poll_flush(cx), + } + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_close(cx), + Either::Right(x) => x.poll_close(cx), + } + } + } + + impl<A, B> AsyncSeek for Either<A, B> + where + A: AsyncSeek, + B: AsyncSeek, + { + fn poll_seek( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + pos: SeekFrom, + ) -> Poll<Result<u64>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_seek(cx, pos), + Either::Right(x) => x.poll_seek(cx, pos), + } + } + } + + impl<A, B> AsyncBufRead for Either<A, B> + where + A: AsyncBufRead, + B: AsyncBufRead, + { + fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<&[u8]>> { + match self.as_pin_mut() { + Either::Left(x) => x.poll_fill_buf(cx), + Either::Right(x) => x.poll_fill_buf(cx), + } + } + + fn consume(self: Pin<&mut Self>, amt: usize) { + match self.as_pin_mut() { + Either::Left(x) => x.consume(amt), + Either::Right(x) => x.consume(amt), + } + } + } +} diff --git a/third_party/rust/futures-util/src/future/future/catch_unwind.rs b/third_party/rust/futures-util/src/future/future/catch_unwind.rs new file mode 100644 index 0000000000..0e09d6eeb0 --- /dev/null +++ b/third_party/rust/futures-util/src/future/future/catch_unwind.rs @@ -0,0 +1,38 @@ +use core::any::Any; +use core::pin::Pin; +use std::panic::{catch_unwind, AssertUnwindSafe, UnwindSafe}; + +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`catch_unwind`](super::FutureExt::catch_unwind) method. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct CatchUnwind<Fut> { + #[pin] + future: Fut, + } +} + +impl<Fut> CatchUnwind<Fut> +where + Fut: Future + UnwindSafe, +{ + pub(super) fn new(future: Fut) -> Self { + Self { future } + } +} + +impl<Fut> Future for CatchUnwind<Fut> +where + Fut: Future + UnwindSafe, +{ + type Output = Result<Fut::Output, Box<dyn Any + Send>>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let f = self.project().future; + catch_unwind(AssertUnwindSafe(|| f.poll(cx)))?.map(Ok) + } +} diff --git a/third_party/rust/futures-util/src/future/future/flatten.rs b/third_party/rust/futures-util/src/future/future/flatten.rs new file mode 100644 index 0000000000..bd767af344 --- /dev/null +++ b/third_party/rust/futures-util/src/future/future/flatten.rs @@ -0,0 +1,153 @@ +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + #[project = FlattenProj] + #[derive(Debug)] + pub enum Flatten<Fut1, Fut2> { + First { #[pin] f: Fut1 }, + Second { #[pin] f: Fut2 }, + Empty, + } +} + +impl<Fut1, Fut2> Flatten<Fut1, Fut2> { + pub(crate) fn new(future: Fut1) -> Self { + Self::First { f: future } + } +} + +impl<Fut> FusedFuture for Flatten<Fut, Fut::Output> +where + Fut: Future, + Fut::Output: Future, +{ + fn is_terminated(&self) -> bool { + match self { + Self::Empty => true, + _ => false, + } + } +} + +impl<Fut> Future for Flatten<Fut, Fut::Output> +where + Fut: Future, + Fut::Output: Future, +{ + type Output = <Fut::Output as Future>::Output; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + Poll::Ready(loop { + match self.as_mut().project() { + FlattenProj::First { f } => { + let f = ready!(f.poll(cx)); + self.set(Self::Second { f }); + } + FlattenProj::Second { f } => { + let output = ready!(f.poll(cx)); + self.set(Self::Empty); + break output; + } + FlattenProj::Empty => panic!("Flatten polled after completion"), + } + }) + } +} + +impl<Fut> FusedStream for Flatten<Fut, Fut::Output> +where + Fut: Future, + Fut::Output: Stream, +{ + fn is_terminated(&self) -> bool { + match self { + Self::Empty => true, + _ => false, + } + } +} + +impl<Fut> Stream for Flatten<Fut, Fut::Output> +where + Fut: Future, + Fut::Output: Stream, +{ + type Item = <Fut::Output as Stream>::Item; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + Poll::Ready(loop { + match self.as_mut().project() { + FlattenProj::First { f } => { + let f = ready!(f.poll(cx)); + self.set(Self::Second { f }); + } + FlattenProj::Second { f } => { + let output = ready!(f.poll_next(cx)); + if output.is_none() { + self.set(Self::Empty); + } + break output; + } + FlattenProj::Empty => break None, + } + }) + } +} + +#[cfg(feature = "sink")] +impl<Fut, Item> Sink<Item> for Flatten<Fut, Fut::Output> +where + Fut: Future, + Fut::Output: Sink<Item>, +{ + type Error = <Fut::Output as Sink<Item>>::Error; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + Poll::Ready(loop { + match self.as_mut().project() { + FlattenProj::First { f } => { + let f = ready!(f.poll(cx)); + self.set(Self::Second { f }); + } + FlattenProj::Second { f } => { + break ready!(f.poll_ready(cx)); + } + FlattenProj::Empty => panic!("poll_ready called after eof"), + } + }) + } + + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + match self.project() { + FlattenProj::First { .. } => panic!("poll_ready not called first"), + FlattenProj::Second { f } => f.start_send(item), + FlattenProj::Empty => panic!("start_send called after eof"), + } + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + match self.project() { + FlattenProj::First { .. } => Poll::Ready(Ok(())), + FlattenProj::Second { f } => f.poll_flush(cx), + FlattenProj::Empty => panic!("poll_flush called after eof"), + } + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + let res = match self.as_mut().project() { + FlattenProj::Second { f } => f.poll_close(cx), + _ => Poll::Ready(Ok(())), + }; + if res.is_ready() { + self.set(Self::Empty); + } + res + } +} diff --git a/third_party/rust/futures-util/src/future/future/fuse.rs b/third_party/rust/futures-util/src/future/future/fuse.rs new file mode 100644 index 0000000000..597aec1a40 --- /dev/null +++ b/third_party/rust/futures-util/src/future/future/fuse.rs @@ -0,0 +1,93 @@ +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`fuse`](super::FutureExt::fuse) method. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Fuse<Fut> { + #[pin] + inner: Option<Fut>, + } +} + +impl<Fut> Fuse<Fut> { + pub(super) fn new(f: Fut) -> Self { + Self { inner: Some(f) } + } +} + +impl<Fut: Future> Fuse<Fut> { + /// Creates a new `Fuse`-wrapped future which is already terminated. + /// + /// This can be useful in combination with looping and the `select!` + /// macro, which bypasses terminated futures. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::future::{Fuse, FusedFuture, FutureExt}; + /// use futures::select; + /// use futures::stream::StreamExt; + /// use futures::pin_mut; + /// + /// let (sender, mut stream) = mpsc::unbounded(); + /// + /// // Send a few messages into the stream + /// sender.unbounded_send(()).unwrap(); + /// sender.unbounded_send(()).unwrap(); + /// drop(sender); + /// + /// // Use `Fuse::terminated()` to create an already-terminated future + /// // which may be instantiated later. + /// let foo_printer = Fuse::terminated(); + /// pin_mut!(foo_printer); + /// + /// loop { + /// select! { + /// _ = foo_printer => {}, + /// () = stream.select_next_some() => { + /// if !foo_printer.is_terminated() { + /// println!("Foo is already being printed!"); + /// } else { + /// foo_printer.set(async { + /// // do some other async operations + /// println!("Printing foo from `foo_printer` future"); + /// }.fuse()); + /// } + /// }, + /// complete => break, // `foo_printer` is terminated and the stream is done + /// } + /// } + /// # }); + /// ``` + pub fn terminated() -> Self { + Self { inner: None } + } +} + +impl<Fut: Future> FusedFuture for Fuse<Fut> { + fn is_terminated(&self) -> bool { + self.inner.is_none() + } +} + +impl<Fut: Future> Future for Fuse<Fut> { + type Output = Fut::Output; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Fut::Output> { + Poll::Ready(match self.as_mut().project().inner.as_pin_mut() { + Some(fut) => { + let output = ready!(fut.poll(cx)); + self.project().inner.set(None); + output + } + None => return Poll::Pending, + }) + } +} diff --git a/third_party/rust/futures-util/src/future/future/map.rs b/third_party/rust/futures-util/src/future/future/map.rs new file mode 100644 index 0000000000..7471aba000 --- /dev/null +++ b/third_party/rust/futures-util/src/future/future/map.rs @@ -0,0 +1,66 @@ +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +use crate::fns::FnOnce1; + +pin_project! { + /// Internal Map future + #[project = MapProj] + #[project_replace = MapProjReplace] + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub enum Map<Fut, F> { + Incomplete { + #[pin] + future: Fut, + f: F, + }, + Complete, + } +} + +impl<Fut, F> Map<Fut, F> { + /// Creates a new Map. + pub(crate) fn new(future: Fut, f: F) -> Self { + Self::Incomplete { future, f } + } +} + +impl<Fut, F, T> FusedFuture for Map<Fut, F> +where + Fut: Future, + F: FnOnce1<Fut::Output, Output = T>, +{ + fn is_terminated(&self) -> bool { + match self { + Self::Incomplete { .. } => false, + Self::Complete => true, + } + } +} + +impl<Fut, F, T> Future for Map<Fut, F> +where + Fut: Future, + F: FnOnce1<Fut::Output, Output = T>, +{ + type Output = T; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<T> { + match self.as_mut().project() { + MapProj::Incomplete { future, .. } => { + let output = ready!(future.poll(cx)); + match self.project_replace(Map::Complete) { + MapProjReplace::Incomplete { f, .. } => Poll::Ready(f.call_once(output)), + MapProjReplace::Complete => unreachable!(), + } + } + MapProj::Complete => { + panic!("Map must not be polled after it returned `Poll::Ready`") + } + } + } +} diff --git a/third_party/rust/futures-util/src/future/future/mod.rs b/third_party/rust/futures-util/src/future/future/mod.rs new file mode 100644 index 0000000000..c11d108207 --- /dev/null +++ b/third_party/rust/futures-util/src/future/future/mod.rs @@ -0,0 +1,610 @@ +//! Futures +//! +//! This module contains a number of functions for working with `Future`s, +//! including the `FutureExt` trait which adds methods to `Future` types. + +#[cfg(feature = "alloc")] +use alloc::boxed::Box; +use core::pin::Pin; + +use crate::fns::{inspect_fn, into_fn, ok_fn, InspectFn, IntoFn, OkFn}; +use crate::future::{assert_future, Either}; +use crate::never::Never; +use crate::stream::assert_stream; +#[cfg(feature = "alloc")] +use futures_core::future::{BoxFuture, LocalBoxFuture}; +use futures_core::{ + future::Future, + stream::Stream, + task::{Context, Poll}, +}; +use pin_utils::pin_mut; + +// Combinators + +mod flatten; +mod fuse; +mod map; + +delegate_all!( + /// Future for the [`flatten`](super::FutureExt::flatten) method. + Flatten<F>( + flatten::Flatten<F, <F as Future>::Output> + ): Debug + Future + FusedFuture + New[|x: F| flatten::Flatten::new(x)] + where F: Future +); + +delegate_all!( + /// Stream for the [`flatten_stream`](FutureExt::flatten_stream) method. + FlattenStream<F>( + flatten::Flatten<F, <F as Future>::Output> + ): Debug + Sink + Stream + FusedStream + New[|x: F| flatten::Flatten::new(x)] + where F: Future +); + +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use fuse::Fuse; + +delegate_all!( + /// Future for the [`map`](super::FutureExt::map) method. + Map<Fut, F>( + map::Map<Fut, F> + ): Debug + Future + FusedFuture + New[|x: Fut, f: F| map::Map::new(x, f)] +); + +delegate_all!( + /// Stream for the [`into_stream`](FutureExt::into_stream) method. + IntoStream<F>( + crate::stream::Once<F> + ): Debug + Stream + FusedStream + New[|x: F| crate::stream::Once::new(x)] +); + +delegate_all!( + /// Future for the [`map_into`](FutureExt::map_into) combinator. + MapInto<Fut, T>( + Map<Fut, IntoFn<T>> + ): Debug + Future + FusedFuture + New[|x: Fut| Map::new(x, into_fn())] +); + +delegate_all!( + /// Future for the [`then`](FutureExt::then) method. + Then<Fut1, Fut2, F>( + flatten::Flatten<Map<Fut1, F>, Fut2> + ): Debug + Future + FusedFuture + New[|x: Fut1, y: F| flatten::Flatten::new(Map::new(x, y))] +); + +delegate_all!( + /// Future for the [`inspect`](FutureExt::inspect) method. + Inspect<Fut, F>( + map::Map<Fut, InspectFn<F>> + ): Debug + Future + FusedFuture + New[|x: Fut, f: F| map::Map::new(x, inspect_fn(f))] +); + +delegate_all!( + /// Future for the [`never_error`](super::FutureExt::never_error) combinator. + NeverError<Fut>( + Map<Fut, OkFn<Never>> + ): Debug + Future + FusedFuture + New[|x: Fut| Map::new(x, ok_fn())] +); + +delegate_all!( + /// Future for the [`unit_error`](super::FutureExt::unit_error) combinator. + UnitError<Fut>( + Map<Fut, OkFn<()>> + ): Debug + Future + FusedFuture + New[|x: Fut| Map::new(x, ok_fn())] +); + +#[cfg(feature = "std")] +mod catch_unwind; +#[cfg(feature = "std")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::catch_unwind::CatchUnwind; + +#[cfg(feature = "channel")] +#[cfg_attr(docsrs, doc(cfg(feature = "channel")))] +#[cfg(feature = "std")] +mod remote_handle; +#[cfg(feature = "channel")] +#[cfg_attr(docsrs, doc(cfg(feature = "channel")))] +#[cfg(feature = "std")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::remote_handle::{Remote, RemoteHandle}; + +#[cfg(feature = "std")] +mod shared; +#[cfg(feature = "std")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::shared::{Shared, WeakShared}; + +impl<T: ?Sized> FutureExt for T where T: Future {} + +/// An extension trait for `Future`s that provides a variety of convenient +/// adapters. +pub trait FutureExt: Future { + /// Map this future's output to a different type, returning a new future of + /// the resulting type. + /// + /// This function is similar to the `Option::map` or `Iterator::map` where + /// it will change the type of the underlying future. This is useful to + /// chain along a computation once a future has been resolved. + /// + /// Note that this function consumes the receiving future and returns a + /// wrapped version of it, similar to the existing `map` methods in the + /// standard library. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// + /// let future = async { 1 }; + /// let new_future = future.map(|x| x + 3); + /// assert_eq!(new_future.await, 4); + /// # }); + /// ``` + fn map<U, F>(self, f: F) -> Map<Self, F> + where + F: FnOnce(Self::Output) -> U, + Self: Sized, + { + assert_future::<U, _>(Map::new(self, f)) + } + + /// Map this future's output to a different type, returning a new future of + /// the resulting type. + /// + /// This function is equivalent to calling `map(Into::into)` but allows naming + /// the return type. + fn map_into<U>(self) -> MapInto<Self, U> + where + Self::Output: Into<U>, + Self: Sized, + { + assert_future::<U, _>(MapInto::new(self)) + } + + /// Chain on a computation for when a future finished, passing the result of + /// the future to the provided closure `f`. + /// + /// The returned value of the closure must implement the `Future` trait + /// and can represent some more work to be done before the composed future + /// is finished. + /// + /// The closure `f` is only run *after* successful completion of the `self` + /// future. + /// + /// Note that this function consumes the receiving future and returns a + /// wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// + /// let future_of_1 = async { 1 }; + /// let future_of_4 = future_of_1.then(|x| async move { x + 3 }); + /// assert_eq!(future_of_4.await, 4); + /// # }); + /// ``` + fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F> + where + F: FnOnce(Self::Output) -> Fut, + Fut: Future, + Self: Sized, + { + assert_future::<Fut::Output, _>(Then::new(self, f)) + } + + /// Wrap this future in an `Either` future, making it the left-hand variant + /// of that `Either`. + /// + /// This can be used in combination with the `right_future` method to write `if` + /// statements that evaluate to different futures in different branches. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// + /// let x = 6; + /// let future = if x < 10 { + /// async { true }.left_future() + /// } else { + /// async { false }.right_future() + /// }; + /// + /// assert_eq!(future.await, true); + /// # }); + /// ``` + fn left_future<B>(self) -> Either<Self, B> + where + B: Future<Output = Self::Output>, + Self: Sized, + { + assert_future::<Self::Output, _>(Either::Left(self)) + } + + /// Wrap this future in an `Either` future, making it the right-hand variant + /// of that `Either`. + /// + /// This can be used in combination with the `left_future` method to write `if` + /// statements that evaluate to different futures in different branches. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// + /// let x = 6; + /// let future = if x > 10 { + /// async { true }.left_future() + /// } else { + /// async { false }.right_future() + /// }; + /// + /// assert_eq!(future.await, false); + /// # }); + /// ``` + fn right_future<A>(self) -> Either<A, Self> + where + A: Future<Output = Self::Output>, + Self: Sized, + { + assert_future::<Self::Output, _>(Either::Right(self)) + } + + /// Convert this future into a single element stream. + /// + /// The returned stream contains single success if this future resolves to + /// success or single error if this future resolves into error. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// use futures::stream::StreamExt; + /// + /// let future = async { 17 }; + /// let stream = future.into_stream(); + /// let collected: Vec<_> = stream.collect().await; + /// assert_eq!(collected, vec![17]); + /// # }); + /// ``` + fn into_stream(self) -> IntoStream<Self> + where + Self: Sized, + { + assert_stream::<Self::Output, _>(IntoStream::new(self)) + } + + /// Flatten the execution of this future when the output of this + /// future is itself another future. + /// + /// This can be useful when combining futures together to flatten the + /// computation out the final result. + /// + /// This method is roughly equivalent to `self.then(|x| x)`. + /// + /// Note that this function consumes the receiving future and returns a + /// wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// + /// let nested_future = async { async { 1 } }; + /// let future = nested_future.flatten(); + /// assert_eq!(future.await, 1); + /// # }); + /// ``` + fn flatten(self) -> Flatten<Self> + where + Self::Output: Future, + Self: Sized, + { + let f = Flatten::new(self); + assert_future::<<<Self as Future>::Output as Future>::Output, _>(f) + } + + /// Flatten the execution of this future when the successful result of this + /// future is a stream. + /// + /// This can be useful when stream initialization is deferred, and it is + /// convenient to work with that stream as if stream was available at the + /// call site. + /// + /// Note that this function consumes this future and returns a wrapped + /// version of it. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// use futures::stream::{self, StreamExt}; + /// + /// let stream_items = vec![17, 18, 19]; + /// let future_of_a_stream = async { stream::iter(stream_items) }; + /// + /// let stream = future_of_a_stream.flatten_stream(); + /// let list: Vec<_> = stream.collect().await; + /// assert_eq!(list, vec![17, 18, 19]); + /// # }); + /// ``` + fn flatten_stream(self) -> FlattenStream<Self> + where + Self::Output: Stream, + Self: Sized, + { + assert_stream::<<Self::Output as Stream>::Item, _>(FlattenStream::new(self)) + } + + /// Fuse a future such that `poll` will never again be called once it has + /// completed. This method can be used to turn any `Future` into a + /// `FusedFuture`. + /// + /// Normally, once a future has returned `Poll::Ready` from `poll`, + /// any further calls could exhibit bad behavior such as blocking + /// forever, panicking, never returning, etc. If it is known that `poll` + /// may be called too often then this method can be used to ensure that it + /// has defined semantics. + /// + /// If a `fuse`d future is `poll`ed after having returned `Poll::Ready` + /// previously, it will return `Poll::Pending`, from `poll` again (and will + /// continue to do so for all future calls to `poll`). + /// + /// This combinator will drop the underlying future as soon as it has been + /// completed to ensure resources are reclaimed as soon as possible. + fn fuse(self) -> Fuse<Self> + where + Self: Sized, + { + let f = Fuse::new(self); + assert_future::<Self::Output, _>(f) + } + + /// Do something with the output of a future before passing it on. + /// + /// When using futures, you'll often chain several of them together. While + /// working on such code, you might want to check out what's happening at + /// various parts in the pipeline, without consuming the intermediate + /// value. To do that, insert a call to `inspect`. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// + /// let future = async { 1 }; + /// let new_future = future.inspect(|&x| println!("about to resolve: {}", x)); + /// assert_eq!(new_future.await, 1); + /// # }); + /// ``` + fn inspect<F>(self, f: F) -> Inspect<Self, F> + where + F: FnOnce(&Self::Output), + Self: Sized, + { + assert_future::<Self::Output, _>(Inspect::new(self, f)) + } + + /// Catches unwinding panics while polling the future. + /// + /// In general, panics within a future can propagate all the way out to the + /// task level. This combinator makes it possible to halt unwinding within + /// the future itself. It's most commonly used within task executors. It's + /// not recommended to use this for error handling. + /// + /// Note that this method requires the `UnwindSafe` bound from the standard + /// library. This isn't always applied automatically, and the standard + /// library provides an `AssertUnwindSafe` wrapper type to apply it + /// after-the fact. To assist using this method, the `Future` trait is also + /// implemented for `AssertUnwindSafe<F>` where `F` implements `Future`. + /// + /// This method is only available when the `std` feature of this + /// library is activated, and it is activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::{self, FutureExt, Ready}; + /// + /// let future = future::ready(2); + /// assert!(future.catch_unwind().await.is_ok()); + /// + /// let future = future::lazy(|_| -> Ready<i32> { + /// unimplemented!() + /// }); + /// assert!(future.catch_unwind().await.is_err()); + /// # }); + /// ``` + #[cfg(feature = "std")] + fn catch_unwind(self) -> CatchUnwind<Self> + where + Self: Sized + ::std::panic::UnwindSafe, + { + assert_future::<Result<Self::Output, Box<dyn std::any::Any + Send>>, _>(CatchUnwind::new( + self, + )) + } + + /// Create a cloneable handle to this future where all handles will resolve + /// to the same result. + /// + /// The `shared` combinator method provides a method to convert any future + /// into a cloneable future. It enables a future to be polled by multiple + /// threads. + /// + /// This method is only available when the `std` feature of this + /// library is activated, and it is activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// + /// let future = async { 6 }; + /// let shared1 = future.shared(); + /// let shared2 = shared1.clone(); + /// + /// assert_eq!(6, shared1.await); + /// assert_eq!(6, shared2.await); + /// # }); + /// ``` + /// + /// ``` + /// // Note, unlike most examples this is written in the context of a + /// // synchronous function to better illustrate the cross-thread aspect of + /// // the `shared` combinator. + /// + /// # futures::executor::block_on(async { + /// use futures::future::FutureExt; + /// use futures::executor::block_on; + /// use std::thread; + /// + /// let future = async { 6 }; + /// let shared1 = future.shared(); + /// let shared2 = shared1.clone(); + /// let join_handle = thread::spawn(move || { + /// assert_eq!(6, block_on(shared2)); + /// }); + /// assert_eq!(6, shared1.await); + /// join_handle.join().unwrap(); + /// # }); + /// ``` + #[cfg(feature = "std")] + fn shared(self) -> Shared<Self> + where + Self: Sized, + Self::Output: Clone, + { + assert_future::<Self::Output, _>(Shared::new(self)) + } + + /// Turn this future into a future that yields `()` on completion and sends + /// its output to another future on a separate task. + /// + /// This can be used with spawning executors to easily retrieve the result + /// of a future executing on a separate task or thread. + /// + /// This method is only available when the `std` feature of this + /// library is activated, and it is activated by default. + #[cfg(feature = "channel")] + #[cfg_attr(docsrs, doc(cfg(feature = "channel")))] + #[cfg(feature = "std")] + fn remote_handle(self) -> (Remote<Self>, RemoteHandle<Self::Output>) + where + Self: Sized, + { + let (wrapped, handle) = remote_handle::remote_handle(self); + (assert_future::<(), _>(wrapped), handle) + } + + /// Wrap the future in a Box, pinning it. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + #[cfg(feature = "alloc")] + fn boxed<'a>(self) -> BoxFuture<'a, Self::Output> + where + Self: Sized + Send + 'a, + { + assert_future::<Self::Output, _>(Box::pin(self)) + } + + /// Wrap the future in a Box, pinning it. + /// + /// Similar to `boxed`, but without the `Send` requirement. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + #[cfg(feature = "alloc")] + fn boxed_local<'a>(self) -> LocalBoxFuture<'a, Self::Output> + where + Self: Sized + 'a, + { + assert_future::<Self::Output, _>(Box::pin(self)) + } + + /// Turns a [`Future<Output = T>`](Future) into a + /// [`TryFuture<Ok = T, Error = ()`>](futures_core::future::TryFuture). + fn unit_error(self) -> UnitError<Self> + where + Self: Sized, + { + assert_future::<Result<Self::Output, ()>, _>(UnitError::new(self)) + } + + /// Turns a [`Future<Output = T>`](Future) into a + /// [`TryFuture<Ok = T, Error = Never`>](futures_core::future::TryFuture). + fn never_error(self) -> NeverError<Self> + where + Self: Sized, + { + assert_future::<Result<Self::Output, Never>, _>(NeverError::new(self)) + } + + /// A convenience for calling `Future::poll` on `Unpin` future types. + fn poll_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Self::Output> + where + Self: Unpin, + { + Pin::new(self).poll(cx) + } + + /// Evaluates and consumes the future, returning the resulting output if + /// the future is ready after the first call to `Future::poll`. + /// + /// If `poll` instead returns `Poll::Pending`, `None` is returned. + /// + /// This method is useful in cases where immediacy is more important than + /// waiting for a result. It is also convenient for quickly obtaining + /// the value of a future that is known to always resolve immediately. + /// + /// # Examples + /// + /// ``` + /// # use futures::prelude::*; + /// use futures::{future::ready, future::pending}; + /// let future_ready = ready("foobar"); + /// let future_pending = pending::<&'static str>(); + /// + /// assert_eq!(future_ready.now_or_never(), Some("foobar")); + /// assert_eq!(future_pending.now_or_never(), None); + /// ``` + /// + /// In cases where it is absolutely known that a future should always + /// resolve immediately and never return `Poll::Pending`, this method can + /// be combined with `expect()`: + /// + /// ``` + /// # use futures::{prelude::*, future::ready}; + /// let future_ready = ready("foobar"); + /// + /// assert_eq!(future_ready.now_or_never().expect("Future not ready"), "foobar"); + /// ``` + fn now_or_never(self) -> Option<Self::Output> + where + Self: Sized, + { + let noop_waker = crate::task::noop_waker(); + let mut cx = Context::from_waker(&noop_waker); + + let this = self; + pin_mut!(this); + match this.poll(&mut cx) { + Poll::Ready(x) => Some(x), + _ => None, + } + } +} diff --git a/third_party/rust/futures-util/src/future/future/remote_handle.rs b/third_party/rust/futures-util/src/future/future/remote_handle.rs new file mode 100644 index 0000000000..1358902cab --- /dev/null +++ b/third_party/rust/futures-util/src/future/future/remote_handle.rs @@ -0,0 +1,126 @@ +use { + crate::future::{CatchUnwind, FutureExt}, + futures_channel::oneshot::{self, Receiver, Sender}, + futures_core::{ + future::Future, + ready, + task::{Context, Poll}, + }, + pin_project_lite::pin_project, + std::{ + any::Any, + fmt, + panic::{self, AssertUnwindSafe}, + pin::Pin, + sync::{ + atomic::{AtomicBool, Ordering}, + Arc, + }, + thread, + }, +}; + +/// The handle to a remote future returned by +/// [`remote_handle`](crate::future::FutureExt::remote_handle). When you drop this, +/// the remote future will be woken up to be dropped by the executor. +/// +/// ## Unwind safety +/// +/// When the remote future panics, [Remote] will catch the unwind and transfer it to +/// the thread where `RemoteHandle` is being awaited. This is good for the common +/// case where [Remote] is spawned on a threadpool. It is unlikely that other code +/// in the executor working thread shares mutable data with the spawned future and we +/// preserve the executor from losing its working threads. +/// +/// If you run the future locally and send the handle of to be awaited elsewhere, you +/// must be careful with regard to unwind safety because the thread in which the future +/// is polled will keep running after the panic and the thread running the [RemoteHandle] +/// will unwind. +#[must_use = "dropping a remote handle cancels the underlying future"] +#[derive(Debug)] +#[cfg_attr(docsrs, doc(cfg(feature = "channel")))] +pub struct RemoteHandle<T> { + rx: Receiver<thread::Result<T>>, + keep_running: Arc<AtomicBool>, +} + +impl<T> RemoteHandle<T> { + /// Drops this handle *without* canceling the underlying future. + /// + /// This method can be used if you want to drop the handle, but let the + /// execution continue. + pub fn forget(self) { + self.keep_running.store(true, Ordering::SeqCst); + } +} + +impl<T: 'static> Future for RemoteHandle<T> { + type Output = T; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<T> { + match ready!(self.rx.poll_unpin(cx)) { + Ok(Ok(output)) => Poll::Ready(output), + // the remote future panicked. + Ok(Err(e)) => panic::resume_unwind(e), + // The oneshot sender was dropped. + Err(e) => panic::resume_unwind(Box::new(e)), + } + } +} + +type SendMsg<Fut> = Result<<Fut as Future>::Output, Box<(dyn Any + Send + 'static)>>; + +pin_project! { + /// A future which sends its output to the corresponding `RemoteHandle`. + /// Created by [`remote_handle`](crate::future::FutureExt::remote_handle). + #[must_use = "futures do nothing unless you `.await` or poll them"] + #[cfg_attr(docsrs, doc(cfg(feature = "channel")))] + pub struct Remote<Fut: Future> { + tx: Option<Sender<SendMsg<Fut>>>, + keep_running: Arc<AtomicBool>, + #[pin] + future: CatchUnwind<AssertUnwindSafe<Fut>>, + } +} + +impl<Fut: Future + fmt::Debug> fmt::Debug for Remote<Fut> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple("Remote").field(&self.future).finish() + } +} + +impl<Fut: Future> Future for Remote<Fut> { + type Output = (); + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> { + let this = self.project(); + + if this.tx.as_mut().unwrap().poll_canceled(cx).is_ready() + && !this.keep_running.load(Ordering::SeqCst) + { + // Cancelled, bail out + return Poll::Ready(()); + } + + let output = ready!(this.future.poll(cx)); + + // if the receiving end has gone away then that's ok, we just ignore the + // send error here. + drop(this.tx.take().unwrap().send(output)); + Poll::Ready(()) + } +} + +pub(super) fn remote_handle<Fut: Future>(future: Fut) -> (Remote<Fut>, RemoteHandle<Fut::Output>) { + let (tx, rx) = oneshot::channel(); + let keep_running = Arc::new(AtomicBool::new(false)); + + // Unwind Safety: See the docs for RemoteHandle. + let wrapped = Remote { + future: AssertUnwindSafe(future).catch_unwind(), + tx: Some(tx), + keep_running: keep_running.clone(), + }; + + (wrapped, RemoteHandle { rx, keep_running }) +} diff --git a/third_party/rust/futures-util/src/future/future/shared.rs b/third_party/rust/futures-util/src/future/future/shared.rs new file mode 100644 index 0000000000..ecd1b426db --- /dev/null +++ b/third_party/rust/futures-util/src/future/future/shared.rs @@ -0,0 +1,413 @@ +use crate::task::{waker_ref, ArcWake}; +use futures_core::future::{FusedFuture, Future}; +use futures_core::task::{Context, Poll, Waker}; +use slab::Slab; +use std::cell::UnsafeCell; +use std::fmt; +use std::hash::Hasher; +use std::pin::Pin; +use std::ptr; +use std::sync::atomic::AtomicUsize; +use std::sync::atomic::Ordering::{Acquire, SeqCst}; +use std::sync::{Arc, Mutex, Weak}; + +/// Future for the [`shared`](super::FutureExt::shared) method. +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Shared<Fut: Future> { + inner: Option<Arc<Inner<Fut>>>, + waker_key: usize, +} + +struct Inner<Fut: Future> { + future_or_output: UnsafeCell<FutureOrOutput<Fut>>, + notifier: Arc<Notifier>, +} + +struct Notifier { + state: AtomicUsize, + wakers: Mutex<Option<Slab<Option<Waker>>>>, +} + +/// A weak reference to a [`Shared`] that can be upgraded much like an `Arc`. +pub struct WeakShared<Fut: Future>(Weak<Inner<Fut>>); + +impl<Fut: Future> Clone for WeakShared<Fut> { + fn clone(&self) -> Self { + Self(self.0.clone()) + } +} + +// The future itself is polled behind the `Arc`, so it won't be moved +// when `Shared` is moved. +impl<Fut: Future> Unpin for Shared<Fut> {} + +impl<Fut: Future> fmt::Debug for Shared<Fut> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Shared") + .field("inner", &self.inner) + .field("waker_key", &self.waker_key) + .finish() + } +} + +impl<Fut: Future> fmt::Debug for Inner<Fut> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Inner").finish() + } +} + +impl<Fut: Future> fmt::Debug for WeakShared<Fut> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("WeakShared").finish() + } +} + +enum FutureOrOutput<Fut: Future> { + Future(Fut), + Output(Fut::Output), +} + +unsafe impl<Fut> Send for Inner<Fut> +where + Fut: Future + Send, + Fut::Output: Send + Sync, +{ +} + +unsafe impl<Fut> Sync for Inner<Fut> +where + Fut: Future + Send, + Fut::Output: Send + Sync, +{ +} + +const IDLE: usize = 0; +const POLLING: usize = 1; +const COMPLETE: usize = 2; +const POISONED: usize = 3; + +const NULL_WAKER_KEY: usize = usize::max_value(); + +impl<Fut: Future> Shared<Fut> { + pub(super) fn new(future: Fut) -> Self { + let inner = Inner { + future_or_output: UnsafeCell::new(FutureOrOutput::Future(future)), + notifier: Arc::new(Notifier { + state: AtomicUsize::new(IDLE), + wakers: Mutex::new(Some(Slab::new())), + }), + }; + + Self { inner: Some(Arc::new(inner)), waker_key: NULL_WAKER_KEY } + } +} + +impl<Fut> Shared<Fut> +where + Fut: Future, +{ + /// Returns [`Some`] containing a reference to this [`Shared`]'s output if + /// it has already been computed by a clone or [`None`] if it hasn't been + /// computed yet or this [`Shared`] already returned its output from + /// [`poll`](Future::poll). + pub fn peek(&self) -> Option<&Fut::Output> { + if let Some(inner) = self.inner.as_ref() { + match inner.notifier.state.load(SeqCst) { + COMPLETE => unsafe { return Some(inner.output()) }, + POISONED => panic!("inner future panicked during poll"), + _ => {} + } + } + None + } + + /// Creates a new [`WeakShared`] for this [`Shared`]. + /// + /// Returns [`None`] if it has already been polled to completion. + pub fn downgrade(&self) -> Option<WeakShared<Fut>> { + if let Some(inner) = self.inner.as_ref() { + return Some(WeakShared(Arc::downgrade(inner))); + } + None + } + + /// Gets the number of strong pointers to this allocation. + /// + /// Returns [`None`] if it has already been polled to completion. + /// + /// # Safety + /// + /// This method by itself is safe, but using it correctly requires extra care. Another thread + /// can change the strong count at any time, including potentially between calling this method + /// and acting on the result. + #[allow(clippy::unnecessary_safety_doc)] + pub fn strong_count(&self) -> Option<usize> { + self.inner.as_ref().map(|arc| Arc::strong_count(arc)) + } + + /// Gets the number of weak pointers to this allocation. + /// + /// Returns [`None`] if it has already been polled to completion. + /// + /// # Safety + /// + /// This method by itself is safe, but using it correctly requires extra care. Another thread + /// can change the weak count at any time, including potentially between calling this method + /// and acting on the result. + #[allow(clippy::unnecessary_safety_doc)] + pub fn weak_count(&self) -> Option<usize> { + self.inner.as_ref().map(|arc| Arc::weak_count(arc)) + } + + /// Hashes the internal state of this `Shared` in a way that's compatible with `ptr_eq`. + pub fn ptr_hash<H: Hasher>(&self, state: &mut H) { + match self.inner.as_ref() { + Some(arc) => { + state.write_u8(1); + ptr::hash(Arc::as_ptr(arc), state); + } + None => { + state.write_u8(0); + } + } + } + + /// Returns `true` if the two `Shared`s point to the same future (in a vein similar to + /// `Arc::ptr_eq`). + /// + /// Returns `false` if either `Shared` has terminated. + pub fn ptr_eq(&self, rhs: &Self) -> bool { + let lhs = match self.inner.as_ref() { + Some(lhs) => lhs, + None => return false, + }; + let rhs = match rhs.inner.as_ref() { + Some(rhs) => rhs, + None => return false, + }; + Arc::ptr_eq(lhs, rhs) + } +} + +impl<Fut> Inner<Fut> +where + Fut: Future, +{ + /// Safety: callers must first ensure that `self.inner.state` + /// is `COMPLETE` + unsafe fn output(&self) -> &Fut::Output { + match &*self.future_or_output.get() { + FutureOrOutput::Output(ref item) => item, + FutureOrOutput::Future(_) => unreachable!(), + } + } +} + +impl<Fut> Inner<Fut> +where + Fut: Future, + Fut::Output: Clone, +{ + /// Registers the current task to receive a wakeup when we are awoken. + fn record_waker(&self, waker_key: &mut usize, cx: &mut Context<'_>) { + let mut wakers_guard = self.notifier.wakers.lock().unwrap(); + + let wakers = match wakers_guard.as_mut() { + Some(wakers) => wakers, + None => return, + }; + + let new_waker = cx.waker(); + + if *waker_key == NULL_WAKER_KEY { + *waker_key = wakers.insert(Some(new_waker.clone())); + } else { + match wakers[*waker_key] { + Some(ref old_waker) if new_waker.will_wake(old_waker) => {} + // Could use clone_from here, but Waker doesn't specialize it. + ref mut slot => *slot = Some(new_waker.clone()), + } + } + debug_assert!(*waker_key != NULL_WAKER_KEY); + } + + /// Safety: callers must first ensure that `inner.state` + /// is `COMPLETE` + unsafe fn take_or_clone_output(self: Arc<Self>) -> Fut::Output { + match Arc::try_unwrap(self) { + Ok(inner) => match inner.future_or_output.into_inner() { + FutureOrOutput::Output(item) => item, + FutureOrOutput::Future(_) => unreachable!(), + }, + Err(inner) => inner.output().clone(), + } + } +} + +impl<Fut> FusedFuture for Shared<Fut> +where + Fut: Future, + Fut::Output: Clone, +{ + fn is_terminated(&self) -> bool { + self.inner.is_none() + } +} + +impl<Fut> Future for Shared<Fut> +where + Fut: Future, + Fut::Output: Clone, +{ + type Output = Fut::Output; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + + let inner = this.inner.take().expect("Shared future polled again after completion"); + + // Fast path for when the wrapped future has already completed + if inner.notifier.state.load(Acquire) == COMPLETE { + // Safety: We're in the COMPLETE state + return unsafe { Poll::Ready(inner.take_or_clone_output()) }; + } + + inner.record_waker(&mut this.waker_key, cx); + + match inner + .notifier + .state + .compare_exchange(IDLE, POLLING, SeqCst, SeqCst) + .unwrap_or_else(|x| x) + { + IDLE => { + // Lock acquired, fall through + } + POLLING => { + // Another task is currently polling, at this point we just want + // to ensure that the waker for this task is registered + this.inner = Some(inner); + return Poll::Pending; + } + COMPLETE => { + // Safety: We're in the COMPLETE state + return unsafe { Poll::Ready(inner.take_or_clone_output()) }; + } + POISONED => panic!("inner future panicked during poll"), + _ => unreachable!(), + } + + let waker = waker_ref(&inner.notifier); + let mut cx = Context::from_waker(&waker); + + struct Reset<'a> { + state: &'a AtomicUsize, + did_not_panic: bool, + } + + impl Drop for Reset<'_> { + fn drop(&mut self) { + if !self.did_not_panic { + self.state.store(POISONED, SeqCst); + } + } + } + + let mut reset = Reset { state: &inner.notifier.state, did_not_panic: false }; + + let output = { + let future = unsafe { + match &mut *inner.future_or_output.get() { + FutureOrOutput::Future(fut) => Pin::new_unchecked(fut), + _ => unreachable!(), + } + }; + + let poll_result = future.poll(&mut cx); + reset.did_not_panic = true; + + match poll_result { + Poll::Pending => { + if inner.notifier.state.compare_exchange(POLLING, IDLE, SeqCst, SeqCst).is_ok() + { + // Success + drop(reset); + this.inner = Some(inner); + return Poll::Pending; + } else { + unreachable!() + } + } + Poll::Ready(output) => output, + } + }; + + unsafe { + *inner.future_or_output.get() = FutureOrOutput::Output(output); + } + + inner.notifier.state.store(COMPLETE, SeqCst); + + // Wake all tasks and drop the slab + let mut wakers_guard = inner.notifier.wakers.lock().unwrap(); + let mut wakers = wakers_guard.take().unwrap(); + for waker in wakers.drain().flatten() { + waker.wake(); + } + + drop(reset); // Make borrow checker happy + drop(wakers_guard); + + // Safety: We're in the COMPLETE state + unsafe { Poll::Ready(inner.take_or_clone_output()) } + } +} + +impl<Fut> Clone for Shared<Fut> +where + Fut: Future, +{ + fn clone(&self) -> Self { + Self { inner: self.inner.clone(), waker_key: NULL_WAKER_KEY } + } +} + +impl<Fut> Drop for Shared<Fut> +where + Fut: Future, +{ + fn drop(&mut self) { + if self.waker_key != NULL_WAKER_KEY { + if let Some(ref inner) = self.inner { + if let Ok(mut wakers) = inner.notifier.wakers.lock() { + if let Some(wakers) = wakers.as_mut() { + wakers.remove(self.waker_key); + } + } + } + } + } +} + +impl ArcWake for Notifier { + fn wake_by_ref(arc_self: &Arc<Self>) { + let wakers = &mut *arc_self.wakers.lock().unwrap(); + if let Some(wakers) = wakers.as_mut() { + for (_key, opt_waker) in wakers { + if let Some(waker) = opt_waker.take() { + waker.wake(); + } + } + } + } +} + +impl<Fut: Future> WeakShared<Fut> { + /// Attempts to upgrade this [`WeakShared`] into a [`Shared`]. + /// + /// Returns [`None`] if all clones of the [`Shared`] have been dropped or polled + /// to completion. + pub fn upgrade(&self) -> Option<Shared<Fut>> { + Some(Shared { inner: Some(self.0.upgrade()?), waker_key: NULL_WAKER_KEY }) + } +} diff --git a/third_party/rust/futures-util/src/future/join.rs b/third_party/rust/futures-util/src/future/join.rs new file mode 100644 index 0000000000..740ffbc988 --- /dev/null +++ b/third_party/rust/futures-util/src/future/join.rs @@ -0,0 +1,217 @@ +#![allow(non_snake_case)] + +use super::assert_future; +use crate::future::{maybe_done, MaybeDone}; +use core::fmt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +macro_rules! generate { + ($( + $(#[$doc:meta])* + ($Join:ident, <$($Fut:ident),*>), + )*) => ($( + pin_project! { + $(#[$doc])* + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct $Join<$($Fut: Future),*> { + $(#[pin] $Fut: MaybeDone<$Fut>,)* + } + } + + impl<$($Fut),*> fmt::Debug for $Join<$($Fut),*> + where + $( + $Fut: Future + fmt::Debug, + $Fut::Output: fmt::Debug, + )* + { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct(stringify!($Join)) + $(.field(stringify!($Fut), &self.$Fut))* + .finish() + } + } + + impl<$($Fut: Future),*> $Join<$($Fut),*> { + fn new($($Fut: $Fut),*) -> Self { + Self { + $($Fut: maybe_done($Fut)),* + } + } + } + + impl<$($Fut: Future),*> Future for $Join<$($Fut),*> { + type Output = ($($Fut::Output),*); + + fn poll( + self: Pin<&mut Self>, cx: &mut Context<'_> + ) -> Poll<Self::Output> { + let mut all_done = true; + let mut futures = self.project(); + $( + all_done &= futures.$Fut.as_mut().poll(cx).is_ready(); + )* + + if all_done { + Poll::Ready(($(futures.$Fut.take_output().unwrap()), *)) + } else { + Poll::Pending + } + } + } + + impl<$($Fut: FusedFuture),*> FusedFuture for $Join<$($Fut),*> { + fn is_terminated(&self) -> bool { + $( + self.$Fut.is_terminated() + ) && * + } + } + )*) +} + +generate! { + /// Future for the [`join`](join()) function. + (Join, <Fut1, Fut2>), + + /// Future for the [`join3`] function. + (Join3, <Fut1, Fut2, Fut3>), + + /// Future for the [`join4`] function. + (Join4, <Fut1, Fut2, Fut3, Fut4>), + + /// Future for the [`join5`] function. + (Join5, <Fut1, Fut2, Fut3, Fut4, Fut5>), +} + +/// Joins the result of two futures, waiting for them both to complete. +/// +/// This function will return a new future which awaits both futures to +/// complete. The returned future will finish with a tuple of both results. +/// +/// Note that this function consumes the passed futures and returns a +/// wrapped version of it. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = async { 1 }; +/// let b = async { 2 }; +/// let pair = future::join(a, b); +/// +/// assert_eq!(pair.await, (1, 2)); +/// # }); +/// ``` +pub fn join<Fut1, Fut2>(future1: Fut1, future2: Fut2) -> Join<Fut1, Fut2> +where + Fut1: Future, + Fut2: Future, +{ + let f = Join::new(future1, future2); + assert_future::<(Fut1::Output, Fut2::Output), _>(f) +} + +/// Same as [`join`](join()), but with more futures. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = async { 1 }; +/// let b = async { 2 }; +/// let c = async { 3 }; +/// let tuple = future::join3(a, b, c); +/// +/// assert_eq!(tuple.await, (1, 2, 3)); +/// # }); +/// ``` +pub fn join3<Fut1, Fut2, Fut3>( + future1: Fut1, + future2: Fut2, + future3: Fut3, +) -> Join3<Fut1, Fut2, Fut3> +where + Fut1: Future, + Fut2: Future, + Fut3: Future, +{ + let f = Join3::new(future1, future2, future3); + assert_future::<(Fut1::Output, Fut2::Output, Fut3::Output), _>(f) +} + +/// Same as [`join`](join()), but with more futures. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = async { 1 }; +/// let b = async { 2 }; +/// let c = async { 3 }; +/// let d = async { 4 }; +/// let tuple = future::join4(a, b, c, d); +/// +/// assert_eq!(tuple.await, (1, 2, 3, 4)); +/// # }); +/// ``` +pub fn join4<Fut1, Fut2, Fut3, Fut4>( + future1: Fut1, + future2: Fut2, + future3: Fut3, + future4: Fut4, +) -> Join4<Fut1, Fut2, Fut3, Fut4> +where + Fut1: Future, + Fut2: Future, + Fut3: Future, + Fut4: Future, +{ + let f = Join4::new(future1, future2, future3, future4); + assert_future::<(Fut1::Output, Fut2::Output, Fut3::Output, Fut4::Output), _>(f) +} + +/// Same as [`join`](join()), but with more futures. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = async { 1 }; +/// let b = async { 2 }; +/// let c = async { 3 }; +/// let d = async { 4 }; +/// let e = async { 5 }; +/// let tuple = future::join5(a, b, c, d, e); +/// +/// assert_eq!(tuple.await, (1, 2, 3, 4, 5)); +/// # }); +/// ``` +pub fn join5<Fut1, Fut2, Fut3, Fut4, Fut5>( + future1: Fut1, + future2: Fut2, + future3: Fut3, + future4: Fut4, + future5: Fut5, +) -> Join5<Fut1, Fut2, Fut3, Fut4, Fut5> +where + Fut1: Future, + Fut2: Future, + Fut3: Future, + Fut4: Future, + Fut5: Future, +{ + let f = Join5::new(future1, future2, future3, future4, future5); + assert_future::<(Fut1::Output, Fut2::Output, Fut3::Output, Fut4::Output, Fut5::Output), _>(f) +} diff --git a/third_party/rust/futures-util/src/future/join_all.rs b/third_party/rust/futures-util/src/future/join_all.rs new file mode 100644 index 0000000000..7dc159ba07 --- /dev/null +++ b/third_party/rust/futures-util/src/future/join_all.rs @@ -0,0 +1,166 @@ +//! Definition of the `JoinAll` combinator, waiting for all of a list of futures +//! to finish. + +use alloc::boxed::Box; +use alloc::vec::Vec; +use core::fmt; +use core::future::Future; +use core::iter::FromIterator; +use core::mem; +use core::pin::Pin; +use core::task::{Context, Poll}; + +use super::{assert_future, MaybeDone}; + +#[cfg(not(futures_no_atomic_cas))] +use crate::stream::{Collect, FuturesOrdered, StreamExt}; + +pub(crate) fn iter_pin_mut<T>(slice: Pin<&mut [T]>) -> impl Iterator<Item = Pin<&mut T>> { + // Safety: `std` _could_ make this unsound if it were to decide Pin's + // invariants aren't required to transmit through slices. Otherwise this has + // the same safety as a normal field pin projection. + unsafe { slice.get_unchecked_mut() }.iter_mut().map(|t| unsafe { Pin::new_unchecked(t) }) +} + +#[must_use = "futures do nothing unless you `.await` or poll them"] +/// Future for the [`join_all`] function. +pub struct JoinAll<F> +where + F: Future, +{ + kind: JoinAllKind<F>, +} + +#[cfg(not(futures_no_atomic_cas))] +pub(crate) const SMALL: usize = 30; + +enum JoinAllKind<F> +where + F: Future, +{ + Small { + elems: Pin<Box<[MaybeDone<F>]>>, + }, + #[cfg(not(futures_no_atomic_cas))] + Big { + fut: Collect<FuturesOrdered<F>, Vec<F::Output>>, + }, +} + +impl<F> fmt::Debug for JoinAll<F> +where + F: Future + fmt::Debug, + F::Output: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self.kind { + JoinAllKind::Small { ref elems } => { + f.debug_struct("JoinAll").field("elems", elems).finish() + } + #[cfg(not(futures_no_atomic_cas))] + JoinAllKind::Big { ref fut, .. } => fmt::Debug::fmt(fut, f), + } + } +} + +/// Creates a future which represents a collection of the outputs of the futures +/// given. +/// +/// The returned future will drive execution for all of its underlying futures, +/// collecting the results into a destination `Vec<T>` in the same order as they +/// were provided. +/// +/// This function is only available when the `std` or `alloc` feature of this +/// library is activated, and it is activated by default. +/// +/// # See Also +/// +/// `join_all` will switch to the more powerful [`FuturesOrdered`] for performance +/// reasons if the number of futures is large. You may want to look into using it or +/// it's counterpart [`FuturesUnordered`][crate::stream::FuturesUnordered] directly. +/// +/// Some examples for additional functionality provided by these are: +/// +/// * Adding new futures to the set even after it has been started. +/// +/// * Only polling the specific futures that have been woken. In cases where +/// you have a lot of futures this will result in much more efficient polling. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future::join_all; +/// +/// async fn foo(i: u32) -> u32 { i } +/// +/// let futures = vec![foo(1), foo(2), foo(3)]; +/// +/// assert_eq!(join_all(futures).await, [1, 2, 3]); +/// # }); +/// ``` +pub fn join_all<I>(iter: I) -> JoinAll<I::Item> +where + I: IntoIterator, + I::Item: Future, +{ + let iter = iter.into_iter(); + + #[cfg(futures_no_atomic_cas)] + { + let kind = + JoinAllKind::Small { elems: iter.map(MaybeDone::Future).collect::<Box<[_]>>().into() }; + + assert_future::<Vec<<I::Item as Future>::Output>, _>(JoinAll { kind }) + } + + #[cfg(not(futures_no_atomic_cas))] + { + let kind = match iter.size_hint().1 { + Some(max) if max <= SMALL => JoinAllKind::Small { + elems: iter.map(MaybeDone::Future).collect::<Box<[_]>>().into(), + }, + _ => JoinAllKind::Big { fut: iter.collect::<FuturesOrdered<_>>().collect() }, + }; + + assert_future::<Vec<<I::Item as Future>::Output>, _>(JoinAll { kind }) + } +} + +impl<F> Future for JoinAll<F> +where + F: Future, +{ + type Output = Vec<F::Output>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + match &mut self.kind { + JoinAllKind::Small { elems } => { + let mut all_done = true; + + for elem in iter_pin_mut(elems.as_mut()) { + if elem.poll(cx).is_pending() { + all_done = false; + } + } + + if all_done { + let mut elems = mem::replace(elems, Box::pin([])); + let result = + iter_pin_mut(elems.as_mut()).map(|e| e.take_output().unwrap()).collect(); + Poll::Ready(result) + } else { + Poll::Pending + } + } + #[cfg(not(futures_no_atomic_cas))] + JoinAllKind::Big { fut } => Pin::new(fut).poll(cx), + } + } +} + +impl<F: Future> FromIterator<F> for JoinAll<F> { + fn from_iter<T: IntoIterator<Item = F>>(iter: T) -> Self { + join_all(iter) + } +} diff --git a/third_party/rust/futures-util/src/future/lazy.rs b/third_party/rust/futures-util/src/future/lazy.rs new file mode 100644 index 0000000000..e9a8cf2fa9 --- /dev/null +++ b/third_party/rust/futures-util/src/future/lazy.rs @@ -0,0 +1,60 @@ +use super::assert_future; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::task::{Context, Poll}; + +/// Future for the [`lazy`] function. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Lazy<F> { + f: Option<F>, +} + +// safe because we never generate `Pin<&mut F>` +impl<F> Unpin for Lazy<F> {} + +/// Creates a new future that allows delayed execution of a closure. +/// +/// The provided closure is only run once the future is polled. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::lazy(|_| 1); +/// assert_eq!(a.await, 1); +/// +/// let b = future::lazy(|_| -> i32 { +/// panic!("oh no!") +/// }); +/// drop(b); // closure is never run +/// # }); +/// ``` +pub fn lazy<F, R>(f: F) -> Lazy<F> +where + F: FnOnce(&mut Context<'_>) -> R, +{ + assert_future::<R, _>(Lazy { f: Some(f) }) +} + +impl<F, R> FusedFuture for Lazy<F> +where + F: FnOnce(&mut Context<'_>) -> R, +{ + fn is_terminated(&self) -> bool { + self.f.is_none() + } +} + +impl<F, R> Future for Lazy<F> +where + F: FnOnce(&mut Context<'_>) -> R, +{ + type Output = R; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<R> { + Poll::Ready((self.f.take().expect("Lazy polled after completion"))(cx)) + } +} diff --git a/third_party/rust/futures-util/src/future/maybe_done.rs b/third_party/rust/futures-util/src/future/maybe_done.rs new file mode 100644 index 0000000000..26e6c27588 --- /dev/null +++ b/third_party/rust/futures-util/src/future/maybe_done.rs @@ -0,0 +1,104 @@ +//! Definition of the MaybeDone combinator + +use super::assert_future; +use core::mem; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::task::{Context, Poll}; + +/// A future that may have completed. +/// +/// This is created by the [`maybe_done()`] function. +#[derive(Debug)] +pub enum MaybeDone<Fut: Future> { + /// A not-yet-completed future + Future(/* #[pin] */ Fut), + /// The output of the completed future + Done(Fut::Output), + /// The empty variant after the result of a [`MaybeDone`] has been + /// taken using the [`take_output`](MaybeDone::take_output) method. + Gone, +} + +impl<Fut: Future + Unpin> Unpin for MaybeDone<Fut> {} + +/// Wraps a future into a `MaybeDone` +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// use futures::pin_mut; +/// +/// let future = future::maybe_done(async { 5 }); +/// pin_mut!(future); +/// assert_eq!(future.as_mut().take_output(), None); +/// let () = future.as_mut().await; +/// assert_eq!(future.as_mut().take_output(), Some(5)); +/// assert_eq!(future.as_mut().take_output(), None); +/// # }); +/// ``` +pub fn maybe_done<Fut: Future>(future: Fut) -> MaybeDone<Fut> { + assert_future::<(), _>(MaybeDone::Future(future)) +} + +impl<Fut: Future> MaybeDone<Fut> { + /// Returns an [`Option`] containing a mutable reference to the output of the future. + /// The output of this method will be [`Some`] if and only if the inner + /// future has been completed and [`take_output`](MaybeDone::take_output) + /// has not yet been called. + #[inline] + pub fn output_mut(self: Pin<&mut Self>) -> Option<&mut Fut::Output> { + unsafe { + match self.get_unchecked_mut() { + MaybeDone::Done(res) => Some(res), + _ => None, + } + } + } + + /// Attempt to take the output of a `MaybeDone` without driving it + /// towards completion. + #[inline] + pub fn take_output(self: Pin<&mut Self>) -> Option<Fut::Output> { + match &*self { + Self::Done(_) => {} + Self::Future(_) | Self::Gone => return None, + } + unsafe { + match mem::replace(self.get_unchecked_mut(), Self::Gone) { + MaybeDone::Done(output) => Some(output), + _ => unreachable!(), + } + } + } +} + +impl<Fut: Future> FusedFuture for MaybeDone<Fut> { + fn is_terminated(&self) -> bool { + match self { + Self::Future(_) => false, + Self::Done(_) | Self::Gone => true, + } + } +} + +impl<Fut: Future> Future for MaybeDone<Fut> { + type Output = (); + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + unsafe { + match self.as_mut().get_unchecked_mut() { + MaybeDone::Future(f) => { + let res = ready!(Pin::new_unchecked(f).poll(cx)); + self.set(Self::Done(res)); + } + MaybeDone::Done(_) => {} + MaybeDone::Gone => panic!("MaybeDone polled after value taken"), + } + } + Poll::Ready(()) + } +} diff --git a/third_party/rust/futures-util/src/future/mod.rs b/third_party/rust/futures-util/src/future/mod.rs new file mode 100644 index 0000000000..374e36512f --- /dev/null +++ b/third_party/rust/futures-util/src/future/mod.rs @@ -0,0 +1,131 @@ +//! Asynchronous values. +//! +//! This module contains: +//! +//! - The [`Future`] trait. +//! - The [`FutureExt`] and [`TryFutureExt`] trait, which provides adapters for +//! chaining and composing futures. +//! - Top-level future combinators like [`lazy`](lazy()) which creates a future +//! from a closure that defines its return value, and [`ready`](ready()), +//! which constructs a future with an immediate defined value. + +#[doc(no_inline)] +pub use core::future::Future; + +#[cfg(feature = "alloc")] +pub use futures_core::future::{BoxFuture, LocalBoxFuture}; +pub use futures_core::future::{FusedFuture, TryFuture}; +pub use futures_task::{FutureObj, LocalFutureObj, UnsafeFutureObj}; + +// Extension traits and combinators +#[allow(clippy::module_inception)] +mod future; +pub use self::future::{ + Flatten, Fuse, FutureExt, Inspect, IntoStream, Map, MapInto, NeverError, Then, UnitError, +}; + +#[deprecated(note = "This is now an alias for [Flatten](Flatten)")] +pub use self::future::FlattenStream; + +#[cfg(feature = "std")] +pub use self::future::CatchUnwind; + +#[cfg(feature = "channel")] +#[cfg_attr(docsrs, doc(cfg(feature = "channel")))] +#[cfg(feature = "std")] +pub use self::future::{Remote, RemoteHandle}; + +#[cfg(feature = "std")] +pub use self::future::{Shared, WeakShared}; + +mod try_future; +pub use self::try_future::{ + AndThen, ErrInto, InspectErr, InspectOk, IntoFuture, MapErr, MapOk, MapOkOrElse, OkInto, + OrElse, TryFlatten, TryFlattenStream, TryFutureExt, UnwrapOrElse, +}; + +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub use self::try_future::FlattenSink; + +// Primitive futures + +mod lazy; +pub use self::lazy::{lazy, Lazy}; + +mod pending; +pub use self::pending::{pending, Pending}; + +mod maybe_done; +pub use self::maybe_done::{maybe_done, MaybeDone}; + +mod try_maybe_done; +pub use self::try_maybe_done::{try_maybe_done, TryMaybeDone}; + +mod option; +pub use self::option::OptionFuture; + +mod poll_fn; +pub use self::poll_fn::{poll_fn, PollFn}; + +mod poll_immediate; +pub use self::poll_immediate::{poll_immediate, PollImmediate}; + +mod ready; +pub use self::ready::{err, ok, ready, Ready}; + +mod join; +pub use self::join::{join, join3, join4, join5, Join, Join3, Join4, Join5}; + +#[cfg(feature = "alloc")] +mod join_all; +#[cfg(feature = "alloc")] +pub use self::join_all::{join_all, JoinAll}; + +mod select; +pub use self::select::{select, Select}; + +#[cfg(feature = "alloc")] +mod select_all; +#[cfg(feature = "alloc")] +pub use self::select_all::{select_all, SelectAll}; + +mod try_join; +pub use self::try_join::{ + try_join, try_join3, try_join4, try_join5, TryJoin, TryJoin3, TryJoin4, TryJoin5, +}; + +#[cfg(feature = "alloc")] +mod try_join_all; +#[cfg(feature = "alloc")] +pub use self::try_join_all::{try_join_all, TryJoinAll}; + +mod try_select; +pub use self::try_select::{try_select, TrySelect}; + +#[cfg(feature = "alloc")] +mod select_ok; +#[cfg(feature = "alloc")] +pub use self::select_ok::{select_ok, SelectOk}; + +mod either; +pub use self::either::Either; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod abortable; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use crate::abortable::{AbortHandle, AbortRegistration, Abortable, Aborted}; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use abortable::abortable; + +// Just a helper function to ensure the futures we're returning all have the +// right implementations. +pub(crate) fn assert_future<T, F>(future: F) -> F +where + F: Future<Output = T>, +{ + future +} diff --git a/third_party/rust/futures-util/src/future/option.rs b/third_party/rust/futures-util/src/future/option.rs new file mode 100644 index 0000000000..0bc377758a --- /dev/null +++ b/third_party/rust/futures-util/src/future/option.rs @@ -0,0 +1,64 @@ +//! Definition of the `Option` (optional step) combinator + +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// A future representing a value which may or may not be present. + /// + /// Created by the [`From`] implementation for [`Option`](std::option::Option). + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::OptionFuture; + /// + /// let mut a: OptionFuture<_> = Some(async { 123 }).into(); + /// assert_eq!(a.await, Some(123)); + /// + /// a = None.into(); + /// assert_eq!(a.await, None); + /// # }); + /// ``` + #[derive(Debug, Clone)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct OptionFuture<F> { + #[pin] + inner: Option<F>, + } +} + +impl<F> Default for OptionFuture<F> { + fn default() -> Self { + Self { inner: None } + } +} + +impl<F: Future> Future for OptionFuture<F> { + type Output = Option<F::Output>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + match self.project().inner.as_pin_mut() { + Some(x) => x.poll(cx).map(Some), + None => Poll::Ready(None), + } + } +} + +impl<F: FusedFuture> FusedFuture for OptionFuture<F> { + fn is_terminated(&self) -> bool { + match &self.inner { + Some(x) => x.is_terminated(), + None => true, + } + } +} + +impl<T> From<Option<T>> for OptionFuture<T> { + fn from(option: Option<T>) -> Self { + Self { inner: option } + } +} diff --git a/third_party/rust/futures-util/src/future/pending.rs b/third_party/rust/futures-util/src/future/pending.rs new file mode 100644 index 0000000000..b8e28686e1 --- /dev/null +++ b/third_party/rust/futures-util/src/future/pending.rs @@ -0,0 +1,55 @@ +use super::assert_future; +use core::marker; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::task::{Context, Poll}; + +/// Future for the [`pending()`] function. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Pending<T> { + _data: marker::PhantomData<T>, +} + +impl<T> FusedFuture for Pending<T> { + fn is_terminated(&self) -> bool { + true + } +} + +/// Creates a future which never resolves, representing a computation that never +/// finishes. +/// +/// The returned future will forever return [`Poll::Pending`]. +/// +/// # Examples +/// +/// ```ignore +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let future = future::pending(); +/// let () = future.await; +/// unreachable!(); +/// # }); +/// ``` +#[cfg_attr(docsrs, doc(alias = "never"))] +pub fn pending<T>() -> Pending<T> { + assert_future::<T, _>(Pending { _data: marker::PhantomData }) +} + +impl<T> Future for Pending<T> { + type Output = T; + + fn poll(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<T> { + Poll::Pending + } +} + +impl<T> Unpin for Pending<T> {} + +impl<T> Clone for Pending<T> { + fn clone(&self) -> Self { + pending() + } +} diff --git a/third_party/rust/futures-util/src/future/poll_fn.rs b/third_party/rust/futures-util/src/future/poll_fn.rs new file mode 100644 index 0000000000..19311570b5 --- /dev/null +++ b/third_party/rust/futures-util/src/future/poll_fn.rs @@ -0,0 +1,58 @@ +//! Definition of the `PollFn` adapter combinator + +use super::assert_future; +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; + +/// Future for the [`poll_fn`] function. +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct PollFn<F> { + f: F, +} + +impl<F> Unpin for PollFn<F> {} + +/// Creates a new future wrapping around a function returning [`Poll`]. +/// +/// Polling the returned future delegates to the wrapped function. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future::poll_fn; +/// use futures::task::{Context, Poll}; +/// +/// fn read_line(_cx: &mut Context<'_>) -> Poll<String> { +/// Poll::Ready("Hello, World!".into()) +/// } +/// +/// let read_future = poll_fn(read_line); +/// assert_eq!(read_future.await, "Hello, World!".to_owned()); +/// # }); +/// ``` +pub fn poll_fn<T, F>(f: F) -> PollFn<F> +where + F: FnMut(&mut Context<'_>) -> Poll<T>, +{ + assert_future::<T, _>(PollFn { f }) +} + +impl<F> fmt::Debug for PollFn<F> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("PollFn").finish() + } +} + +impl<T, F> Future for PollFn<F> +where + F: FnMut(&mut Context<'_>) -> Poll<T>, +{ + type Output = T; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<T> { + (&mut self.f)(cx) + } +} diff --git a/third_party/rust/futures-util/src/future/poll_immediate.rs b/third_party/rust/futures-util/src/future/poll_immediate.rs new file mode 100644 index 0000000000..5ae555c73e --- /dev/null +++ b/third_party/rust/futures-util/src/future/poll_immediate.rs @@ -0,0 +1,126 @@ +use super::assert_future; +use core::pin::Pin; +use futures_core::task::{Context, Poll}; +use futures_core::{FusedFuture, Future, Stream}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`poll_immediate`](poll_immediate()) function. + /// + /// It will never return [Poll::Pending](core::task::Poll::Pending) + #[derive(Debug, Clone)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct PollImmediate<T> { + #[pin] + future: Option<T> + } +} + +impl<T, F> Future for PollImmediate<F> +where + F: Future<Output = T>, +{ + type Output = Option<T>; + + #[inline] + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T>> { + let mut this = self.project(); + let inner = + this.future.as_mut().as_pin_mut().expect("PollImmediate polled after completion"); + match inner.poll(cx) { + Poll::Ready(t) => { + this.future.set(None); + Poll::Ready(Some(t)) + } + Poll::Pending => Poll::Ready(None), + } + } +} + +impl<T: Future> FusedFuture for PollImmediate<T> { + fn is_terminated(&self) -> bool { + self.future.is_none() + } +} + +/// A [Stream](crate::stream::Stream) implementation that can be polled repeatedly until the future is done. +/// The stream will never return [Poll::Pending](core::task::Poll::Pending) +/// so polling it in a tight loop is worse than using a blocking synchronous function. +/// ``` +/// # futures::executor::block_on(async { +/// use futures::task::Poll; +/// use futures::{StreamExt, future, pin_mut}; +/// use future::FusedFuture; +/// +/// let f = async { 1_u32 }; +/// pin_mut!(f); +/// let mut r = future::poll_immediate(f); +/// assert_eq!(r.next().await, Some(Poll::Ready(1))); +/// +/// let f = async {futures::pending!(); 42_u8}; +/// pin_mut!(f); +/// let mut p = future::poll_immediate(f); +/// assert_eq!(p.next().await, Some(Poll::Pending)); +/// assert!(!p.is_terminated()); +/// assert_eq!(p.next().await, Some(Poll::Ready(42))); +/// assert!(p.is_terminated()); +/// assert_eq!(p.next().await, None); +/// # }); +/// ``` +impl<T, F> Stream for PollImmediate<F> +where + F: Future<Output = T>, +{ + type Item = Poll<T>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + match this.future.as_mut().as_pin_mut() { + // inner is gone, so we can signal that the stream is closed. + None => Poll::Ready(None), + Some(fut) => Poll::Ready(Some(fut.poll(cx).map(|t| { + this.future.set(None); + t + }))), + } + } +} + +/// Creates a future that is immediately ready with an Option of a value. +/// Specifically this means that [poll](core::future::Future::poll()) always returns [Poll::Ready](core::task::Poll::Ready). +/// +/// # Caution +/// +/// When consuming the future by this function, note the following: +/// +/// - This function does not guarantee that the future will run to completion, so it is generally incompatible with passing the non-cancellation-safe future by value. +/// - Even if the future is cancellation-safe, creating and dropping new futures frequently may lead to performance problems. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let r = future::poll_immediate(async { 1_u32 }); +/// assert_eq!(r.await, Some(1)); +/// +/// let p = future::poll_immediate(future::pending::<i32>()); +/// assert_eq!(p.await, None); +/// # }); +/// ``` +/// +/// ### Reusing a future +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::{future, pin_mut}; +/// let f = async {futures::pending!(); 42_u8}; +/// pin_mut!(f); +/// assert_eq!(None, future::poll_immediate(&mut f).await); +/// assert_eq!(42, f.await); +/// # }); +/// ``` +pub fn poll_immediate<F: Future>(f: F) -> PollImmediate<F> { + assert_future::<Option<F::Output>, PollImmediate<F>>(PollImmediate { future: Some(f) }) +} diff --git a/third_party/rust/futures-util/src/future/ready.rs b/third_party/rust/futures-util/src/future/ready.rs new file mode 100644 index 0000000000..e3d791b3cf --- /dev/null +++ b/third_party/rust/futures-util/src/future/ready.rs @@ -0,0 +1,82 @@ +use super::assert_future; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::task::{Context, Poll}; + +/// Future for the [`ready`](ready()) function. +#[derive(Debug, Clone)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Ready<T>(Option<T>); + +impl<T> Ready<T> { + /// Unwraps the value from this immediately ready future. + #[inline] + pub fn into_inner(mut self) -> T { + self.0.take().unwrap() + } +} + +impl<T> Unpin for Ready<T> {} + +impl<T> FusedFuture for Ready<T> { + fn is_terminated(&self) -> bool { + self.0.is_none() + } +} + +impl<T> Future for Ready<T> { + type Output = T; + + #[inline] + fn poll(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<T> { + Poll::Ready(self.0.take().expect("Ready polled after completion")) + } +} + +/// Creates a future that is immediately ready with a value. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(1); +/// assert_eq!(a.await, 1); +/// # }); +/// ``` +pub fn ready<T>(t: T) -> Ready<T> { + assert_future::<T, _>(Ready(Some(t))) +} + +/// Create a future that is immediately ready with a success value. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ok::<i32, i32>(1); +/// assert_eq!(a.await, Ok(1)); +/// # }); +/// ``` +pub fn ok<T, E>(t: T) -> Ready<Result<T, E>> { + Ready(Some(Ok(t))) +} + +/// Create a future that is immediately ready with an error value. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::err::<i32, i32>(1); +/// assert_eq!(a.await, Err(1)); +/// # }); +/// ``` +pub fn err<T, E>(err: E) -> Ready<Result<T, E>> { + Ready(Some(Err(err))) +} diff --git a/third_party/rust/futures-util/src/future/select.rs b/third_party/rust/futures-util/src/future/select.rs new file mode 100644 index 0000000000..e693a30b00 --- /dev/null +++ b/third_party/rust/futures-util/src/future/select.rs @@ -0,0 +1,125 @@ +use super::assert_future; +use crate::future::{Either, FutureExt}; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::task::{Context, Poll}; + +/// Future for the [`select()`] function. +#[must_use = "futures do nothing unless you `.await` or poll them"] +#[derive(Debug)] +pub struct Select<A, B> { + inner: Option<(A, B)>, +} + +impl<A: Unpin, B: Unpin> Unpin for Select<A, B> {} + +/// Waits for either one of two differently-typed futures to complete. +/// +/// This function will return a new future which awaits for either one of both +/// futures to complete. The returned future will finish with both the value +/// resolved and a future representing the completion of the other work. +/// +/// Note that this function consumes the receiving futures and returns a +/// wrapped version of them. +/// +/// Also note that if both this and the second future have the same +/// output type you can use the `Either::factor_first` method to +/// conveniently extract out the value at the end. +/// +/// # Examples +/// +/// A simple example +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::{ +/// pin_mut, +/// future::Either, +/// future::self, +/// }; +/// +/// // These two futures have different types even though their outputs have the same type. +/// let future1 = async { +/// future::pending::<()>().await; // will never finish +/// 1 +/// }; +/// let future2 = async { +/// future::ready(2).await +/// }; +/// +/// // 'select' requires Future + Unpin bounds +/// pin_mut!(future1); +/// pin_mut!(future2); +/// +/// let value = match future::select(future1, future2).await { +/// Either::Left((value1, _)) => value1, // `value1` is resolved from `future1` +/// // `_` represents `future2` +/// Either::Right((value2, _)) => value2, // `value2` is resolved from `future2` +/// // `_` represents `future1` +/// }; +/// +/// assert!(value == 2); +/// # }); +/// ``` +/// +/// A more complex example +/// +/// ``` +/// use futures::future::{self, Either, Future, FutureExt}; +/// +/// // A poor-man's join implemented on top of select +/// +/// fn join<A, B>(a: A, b: B) -> impl Future<Output=(A::Output, B::Output)> +/// where A: Future + Unpin, +/// B: Future + Unpin, +/// { +/// future::select(a, b).then(|either| { +/// match either { +/// Either::Left((x, b)) => b.map(move |y| (x, y)).left_future(), +/// Either::Right((y, a)) => a.map(move |x| (x, y)).right_future(), +/// } +/// }) +/// } +/// ``` +pub fn select<A, B>(future1: A, future2: B) -> Select<A, B> +where + A: Future + Unpin, + B: Future + Unpin, +{ + assert_future::<Either<(A::Output, B), (B::Output, A)>, _>(Select { + inner: Some((future1, future2)), + }) +} + +impl<A, B> Future for Select<A, B> +where + A: Future + Unpin, + B: Future + Unpin, +{ + type Output = Either<(A::Output, B), (B::Output, A)>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let (mut a, mut b) = self.inner.take().expect("cannot poll Select twice"); + + if let Poll::Ready(val) = a.poll_unpin(cx) { + return Poll::Ready(Either::Left((val, b))); + } + + if let Poll::Ready(val) = b.poll_unpin(cx) { + return Poll::Ready(Either::Right((val, a))); + } + + self.inner = Some((a, b)); + Poll::Pending + } +} + +impl<A, B> FusedFuture for Select<A, B> +where + A: Future + Unpin, + B: Future + Unpin, +{ + fn is_terminated(&self) -> bool { + self.inner.is_none() + } +} diff --git a/third_party/rust/futures-util/src/future/select_all.rs b/third_party/rust/futures-util/src/future/select_all.rs new file mode 100644 index 0000000000..0a51d0da6c --- /dev/null +++ b/third_party/rust/futures-util/src/future/select_all.rs @@ -0,0 +1,75 @@ +use super::assert_future; +use crate::future::FutureExt; +use alloc::vec::Vec; +use core::iter::FromIterator; +use core::mem; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; + +/// Future for the [`select_all`] function. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct SelectAll<Fut> { + inner: Vec<Fut>, +} + +impl<Fut: Unpin> Unpin for SelectAll<Fut> {} + +/// Creates a new future which will select over a list of futures. +/// +/// The returned future will wait for any future within `iter` to be ready. Upon +/// completion the item resolved will be returned, along with the index of the +/// future that was ready and the list of all the remaining futures. +/// +/// There are no guarantees provided on the order of the list with the remaining +/// futures. They might be swapped around, reversed, or completely random. +/// +/// This function is only available when the `std` or `alloc` feature of this +/// library is activated, and it is activated by default. +/// +/// # Panics +/// +/// This function will panic if the iterator specified contains no items. +pub fn select_all<I>(iter: I) -> SelectAll<I::Item> +where + I: IntoIterator, + I::Item: Future + Unpin, +{ + let ret = SelectAll { inner: iter.into_iter().collect() }; + assert!(!ret.inner.is_empty()); + assert_future::<(<I::Item as Future>::Output, usize, Vec<I::Item>), _>(ret) +} + +impl<Fut> SelectAll<Fut> { + /// Consumes this combinator, returning the underlying futures. + pub fn into_inner(self) -> Vec<Fut> { + self.inner + } +} + +impl<Fut: Future + Unpin> Future for SelectAll<Fut> { + type Output = (Fut::Output, usize, Vec<Fut>); + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let item = self.inner.iter_mut().enumerate().find_map(|(i, f)| match f.poll_unpin(cx) { + Poll::Pending => None, + Poll::Ready(e) => Some((i, e)), + }); + match item { + Some((idx, res)) => { + #[allow(clippy::let_underscore_future)] + let _ = self.inner.swap_remove(idx); + let rest = mem::take(&mut self.inner); + Poll::Ready((res, idx, rest)) + } + None => Poll::Pending, + } + } +} + +impl<Fut: Future + Unpin> FromIterator<Fut> for SelectAll<Fut> { + fn from_iter<T: IntoIterator<Item = Fut>>(iter: T) -> Self { + select_all(iter) + } +} diff --git a/third_party/rust/futures-util/src/future/select_ok.rs b/third_party/rust/futures-util/src/future/select_ok.rs new file mode 100644 index 0000000000..5d5579930b --- /dev/null +++ b/third_party/rust/futures-util/src/future/select_ok.rs @@ -0,0 +1,85 @@ +use super::assert_future; +use crate::future::TryFutureExt; +use alloc::vec::Vec; +use core::iter::FromIterator; +use core::mem; +use core::pin::Pin; +use futures_core::future::{Future, TryFuture}; +use futures_core::task::{Context, Poll}; + +/// Future for the [`select_ok`] function. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct SelectOk<Fut> { + inner: Vec<Fut>, +} + +impl<Fut: Unpin> Unpin for SelectOk<Fut> {} + +/// Creates a new future which will select the first successful future over a list of futures. +/// +/// The returned future will wait for any future within `iter` to be ready and Ok. Unlike +/// `select_all`, this will only return the first successful completion, or the last +/// failure. This is useful in contexts where any success is desired and failures +/// are ignored, unless all the futures fail. +/// +/// This function is only available when the `std` or `alloc` feature of this +/// library is activated, and it is activated by default. +/// +/// # Panics +/// +/// This function will panic if the iterator specified contains no items. +pub fn select_ok<I>(iter: I) -> SelectOk<I::Item> +where + I: IntoIterator, + I::Item: TryFuture + Unpin, +{ + let ret = SelectOk { inner: iter.into_iter().collect() }; + assert!(!ret.inner.is_empty(), "iterator provided to select_ok was empty"); + assert_future::< + Result<(<I::Item as TryFuture>::Ok, Vec<I::Item>), <I::Item as TryFuture>::Error>, + _, + >(ret) +} + +impl<Fut: TryFuture + Unpin> Future for SelectOk<Fut> { + type Output = Result<(Fut::Ok, Vec<Fut>), Fut::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + // loop until we've either exhausted all errors, a success was hit, or nothing is ready + loop { + let item = + self.inner.iter_mut().enumerate().find_map(|(i, f)| match f.try_poll_unpin(cx) { + Poll::Pending => None, + Poll::Ready(e) => Some((i, e)), + }); + match item { + Some((idx, res)) => { + // always remove Ok or Err, if it's not the last Err continue looping + drop(self.inner.remove(idx)); + match res { + Ok(e) => { + let rest = mem::take(&mut self.inner); + return Poll::Ready(Ok((e, rest))); + } + Err(e) => { + if self.inner.is_empty() { + return Poll::Ready(Err(e)); + } + } + } + } + None => { + // based on the filter above, nothing is ready, return + return Poll::Pending; + } + } + } + } +} + +impl<Fut: TryFuture + Unpin> FromIterator<Fut> for SelectOk<Fut> { + fn from_iter<T: IntoIterator<Item = Fut>>(iter: T) -> Self { + select_ok(iter) + } +} diff --git a/third_party/rust/futures-util/src/future/try_future/into_future.rs b/third_party/rust/futures-util/src/future/try_future/into_future.rs new file mode 100644 index 0000000000..9f093d0e2e --- /dev/null +++ b/third_party/rust/futures-util/src/future/try_future/into_future.rs @@ -0,0 +1,36 @@ +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future, TryFuture}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`into_future`](super::TryFutureExt::into_future) method. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct IntoFuture<Fut> { + #[pin] + future: Fut, + } +} + +impl<Fut> IntoFuture<Fut> { + #[inline] + pub(crate) fn new(future: Fut) -> Self { + Self { future } + } +} + +impl<Fut: TryFuture + FusedFuture> FusedFuture for IntoFuture<Fut> { + fn is_terminated(&self) -> bool { + self.future.is_terminated() + } +} + +impl<Fut: TryFuture> Future for IntoFuture<Fut> { + type Output = Result<Fut::Ok, Fut::Error>; + + #[inline] + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + self.project().future.try_poll(cx) + } +} diff --git a/third_party/rust/futures-util/src/future/try_future/mod.rs b/third_party/rust/futures-util/src/future/try_future/mod.rs new file mode 100644 index 0000000000..e5bc700714 --- /dev/null +++ b/third_party/rust/futures-util/src/future/try_future/mod.rs @@ -0,0 +1,625 @@ +//! Futures +//! +//! This module contains a number of functions for working with `Future`s, +//! including the `FutureExt` trait which adds methods to `Future` types. + +#[cfg(feature = "compat")] +use crate::compat::Compat; +use core::pin::Pin; +use futures_core::{ + future::TryFuture, + stream::TryStream, + task::{Context, Poll}, +}; +#[cfg(feature = "sink")] +use futures_sink::Sink; + +use crate::fns::{ + inspect_err_fn, inspect_ok_fn, into_fn, map_err_fn, map_ok_fn, map_ok_or_else_fn, + unwrap_or_else_fn, InspectErrFn, InspectOkFn, IntoFn, MapErrFn, MapOkFn, MapOkOrElseFn, + UnwrapOrElseFn, +}; +use crate::future::{assert_future, Inspect, Map}; +use crate::stream::assert_stream; + +// Combinators +mod into_future; +mod try_flatten; +mod try_flatten_err; + +delegate_all!( + /// Future for the [`try_flatten`](TryFutureExt::try_flatten) method. + TryFlatten<Fut1, Fut2>( + try_flatten::TryFlatten<Fut1, Fut2> + ): Debug + Future + FusedFuture + New[|x: Fut1| try_flatten::TryFlatten::new(x)] +); + +delegate_all!( + /// Future for the [`try_flatten_err`](TryFutureExt::try_flatten_err) method. + TryFlattenErr<Fut1, Fut2>( + try_flatten_err::TryFlattenErr<Fut1, Fut2> + ): Debug + Future + FusedFuture + New[|x: Fut1| try_flatten_err::TryFlattenErr::new(x)] +); + +delegate_all!( + /// Future for the [`try_flatten_stream`](TryFutureExt::try_flatten_stream) method. + TryFlattenStream<Fut>( + try_flatten::TryFlatten<Fut, Fut::Ok> + ): Debug + Sink + Stream + FusedStream + New[|x: Fut| try_flatten::TryFlatten::new(x)] + where Fut: TryFuture +); + +#[cfg(feature = "sink")] +delegate_all!( + /// Sink for the [`flatten_sink`](TryFutureExt::flatten_sink) method. + #[cfg_attr(docsrs, doc(cfg(feature = "sink")))] + FlattenSink<Fut, Si>( + try_flatten::TryFlatten<Fut, Si> + ): Debug + Sink + Stream + FusedStream + New[|x: Fut| try_flatten::TryFlatten::new(x)] +); + +delegate_all!( + /// Future for the [`and_then`](TryFutureExt::and_then) method. + AndThen<Fut1, Fut2, F>( + TryFlatten<MapOk<Fut1, F>, Fut2> + ): Debug + Future + FusedFuture + New[|x: Fut1, f: F| TryFlatten::new(MapOk::new(x, f))] +); + +delegate_all!( + /// Future for the [`or_else`](TryFutureExt::or_else) method. + OrElse<Fut1, Fut2, F>( + TryFlattenErr<MapErr<Fut1, F>, Fut2> + ): Debug + Future + FusedFuture + New[|x: Fut1, f: F| TryFlattenErr::new(MapErr::new(x, f))] +); + +delegate_all!( + /// Future for the [`err_into`](TryFutureExt::err_into) method. + ErrInto<Fut, E>( + MapErr<Fut, IntoFn<E>> + ): Debug + Future + FusedFuture + New[|x: Fut| MapErr::new(x, into_fn())] +); + +delegate_all!( + /// Future for the [`ok_into`](TryFutureExt::ok_into) method. + OkInto<Fut, E>( + MapOk<Fut, IntoFn<E>> + ): Debug + Future + FusedFuture + New[|x: Fut| MapOk::new(x, into_fn())] +); + +delegate_all!( + /// Future for the [`inspect_ok`](super::TryFutureExt::inspect_ok) method. + InspectOk<Fut, F>( + Inspect<IntoFuture<Fut>, InspectOkFn<F>> + ): Debug + Future + FusedFuture + New[|x: Fut, f: F| Inspect::new(IntoFuture::new(x), inspect_ok_fn(f))] +); + +delegate_all!( + /// Future for the [`inspect_err`](super::TryFutureExt::inspect_err) method. + InspectErr<Fut, F>( + Inspect<IntoFuture<Fut>, InspectErrFn<F>> + ): Debug + Future + FusedFuture + New[|x: Fut, f: F| Inspect::new(IntoFuture::new(x), inspect_err_fn(f))] +); + +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::into_future::IntoFuture; + +delegate_all!( + /// Future for the [`map_ok`](TryFutureExt::map_ok) method. + MapOk<Fut, F>( + Map<IntoFuture<Fut>, MapOkFn<F>> + ): Debug + Future + FusedFuture + New[|x: Fut, f: F| Map::new(IntoFuture::new(x), map_ok_fn(f))] +); + +delegate_all!( + /// Future for the [`map_err`](TryFutureExt::map_err) method. + MapErr<Fut, F>( + Map<IntoFuture<Fut>, MapErrFn<F>> + ): Debug + Future + FusedFuture + New[|x: Fut, f: F| Map::new(IntoFuture::new(x), map_err_fn(f))] +); + +delegate_all!( + /// Future for the [`map_ok_or_else`](TryFutureExt::map_ok_or_else) method. + MapOkOrElse<Fut, F, G>( + Map<IntoFuture<Fut>, MapOkOrElseFn<F, G>> + ): Debug + Future + FusedFuture + New[|x: Fut, f: F, g: G| Map::new(IntoFuture::new(x), map_ok_or_else_fn(f, g))] +); + +delegate_all!( + /// Future for the [`unwrap_or_else`](TryFutureExt::unwrap_or_else) method. + UnwrapOrElse<Fut, F>( + Map<IntoFuture<Fut>, UnwrapOrElseFn<F>> + ): Debug + Future + FusedFuture + New[|x: Fut, f: F| Map::new(IntoFuture::new(x), unwrap_or_else_fn(f))] +); + +impl<Fut: ?Sized + TryFuture> TryFutureExt for Fut {} + +/// Adapters specific to [`Result`]-returning futures +pub trait TryFutureExt: TryFuture { + /// Flattens the execution of this future when the successful result of this + /// future is a [`Sink`]. + /// + /// This can be useful when sink initialization is deferred, and it is + /// convenient to work with that sink as if the sink was available at the + /// call site. + /// + /// Note that this function consumes this future and returns a wrapped + /// version of it. + /// + /// # Examples + /// + /// ``` + /// use futures::future::{Future, TryFutureExt}; + /// use futures::sink::Sink; + /// # use futures::channel::mpsc::{self, SendError}; + /// # type T = i32; + /// # type E = SendError; + /// + /// fn make_sink_async() -> impl Future<Output = Result< + /// impl Sink<T, Error = E>, + /// E, + /// >> { // ... } + /// # let (tx, _rx) = mpsc::unbounded::<i32>(); + /// # futures::future::ready(Ok(tx)) + /// # } + /// fn take_sink(sink: impl Sink<T, Error = E>) { /* ... */ } + /// + /// let fut = make_sink_async(); + /// take_sink(fut.flatten_sink()) + /// ``` + #[cfg(feature = "sink")] + #[cfg_attr(docsrs, doc(cfg(feature = "sink")))] + fn flatten_sink<Item>(self) -> FlattenSink<Self, Self::Ok> + where + Self::Ok: Sink<Item, Error = Self::Error>, + Self: Sized, + { + crate::sink::assert_sink::<Item, Self::Error, _>(FlattenSink::new(self)) + } + + /// Maps this future's success value to a different value. + /// + /// This method can be used to change the [`Ok`](TryFuture::Ok) type of the + /// future into a different type. It is similar to the [`Result::map`] + /// method. You can use this method to chain along a computation once the + /// future has been resolved. + /// + /// The provided closure `f` will only be called if this future is resolved + /// to an [`Ok`]. If it resolves to an [`Err`], panics, or is dropped, then + /// the provided closure will never be invoked. + /// + /// Note that this method consumes the future it is called on and returns a + /// wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Ok::<i32, i32>(1) }; + /// let future = future.map_ok(|x| x + 3); + /// assert_eq!(future.await, Ok(4)); + /// # }); + /// ``` + /// + /// Calling [`map_ok`](TryFutureExt::map_ok) on an errored future has no + /// effect: + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Err::<i32, i32>(1) }; + /// let future = future.map_ok(|x| x + 3); + /// assert_eq!(future.await, Err(1)); + /// # }); + /// ``` + fn map_ok<T, F>(self, f: F) -> MapOk<Self, F> + where + F: FnOnce(Self::Ok) -> T, + Self: Sized, + { + assert_future::<Result<T, Self::Error>, _>(MapOk::new(self, f)) + } + + /// Maps this future's success value to a different value, and permits for error handling resulting in the same type. + /// + /// This method can be used to coalesce your [`Ok`](TryFuture::Ok) type and [`Error`](TryFuture::Error) into another type, + /// where that type is the same for both outcomes. + /// + /// The provided closure `f` will only be called if this future is resolved + /// to an [`Ok`]. If it resolves to an [`Err`], panics, or is dropped, then + /// the provided closure will never be invoked. + /// + /// The provided closure `e` will only be called if this future is resolved + /// to an [`Err`]. If it resolves to an [`Ok`], panics, or is dropped, then + /// the provided closure will never be invoked. + /// + /// Note that this method consumes the future it is called on and returns a + /// wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Ok::<i32, i32>(5) }; + /// let future = future.map_ok_or_else(|x| x * 2, |x| x + 3); + /// assert_eq!(future.await, 8); + /// + /// let future = async { Err::<i32, i32>(5) }; + /// let future = future.map_ok_or_else(|x| x * 2, |x| x + 3); + /// assert_eq!(future.await, 10); + /// # }); + /// ``` + /// + fn map_ok_or_else<T, E, F>(self, e: E, f: F) -> MapOkOrElse<Self, F, E> + where + F: FnOnce(Self::Ok) -> T, + E: FnOnce(Self::Error) -> T, + Self: Sized, + { + assert_future::<T, _>(MapOkOrElse::new(self, f, e)) + } + + /// Maps this future's error value to a different value. + /// + /// This method can be used to change the [`Error`](TryFuture::Error) type + /// of the future into a different type. It is similar to the + /// [`Result::map_err`] method. You can use this method for example to + /// ensure that futures have the same [`Error`](TryFuture::Error) type when + /// using [`select!`] or [`join!`]. + /// + /// The provided closure `f` will only be called if this future is resolved + /// to an [`Err`]. If it resolves to an [`Ok`], panics, or is dropped, then + /// the provided closure will never be invoked. + /// + /// Note that this method consumes the future it is called on and returns a + /// wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Err::<i32, i32>(1) }; + /// let future = future.map_err(|x| x + 3); + /// assert_eq!(future.await, Err(4)); + /// # }); + /// ``` + /// + /// Calling [`map_err`](TryFutureExt::map_err) on a successful future has + /// no effect: + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Ok::<i32, i32>(1) }; + /// let future = future.map_err(|x| x + 3); + /// assert_eq!(future.await, Ok(1)); + /// # }); + /// ``` + /// + /// [`join!`]: crate::join + /// [`select!`]: crate::select + fn map_err<E, F>(self, f: F) -> MapErr<Self, F> + where + F: FnOnce(Self::Error) -> E, + Self: Sized, + { + assert_future::<Result<Self::Ok, E>, _>(MapErr::new(self, f)) + } + + /// Maps this future's [`Error`](TryFuture::Error) to a new error type + /// using the [`Into`](std::convert::Into) trait. + /// + /// This method does for futures what the `?`-operator does for + /// [`Result`]: It lets the compiler infer the type of the resulting + /// error. Just as [`map_err`](TryFutureExt::map_err), this is useful for + /// example to ensure that futures have the same [`Error`](TryFuture::Error) + /// type when using [`select!`] or [`join!`]. + /// + /// Note that this method consumes the future it is called on and returns a + /// wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future_err_u8 = async { Err::<(), u8>(1) }; + /// let future_err_i32 = future_err_u8.err_into::<i32>(); + /// # }); + /// ``` + /// + /// [`join!`]: crate::join + /// [`select!`]: crate::select + fn err_into<E>(self) -> ErrInto<Self, E> + where + Self: Sized, + Self::Error: Into<E>, + { + assert_future::<Result<Self::Ok, E>, _>(ErrInto::new(self)) + } + + /// Maps this future's [`Ok`](TryFuture::Ok) to a new type + /// using the [`Into`](std::convert::Into) trait. + fn ok_into<U>(self) -> OkInto<Self, U> + where + Self: Sized, + Self::Ok: Into<U>, + { + assert_future::<Result<U, Self::Error>, _>(OkInto::new(self)) + } + + /// Executes another future after this one resolves successfully. The + /// success value is passed to a closure to create this subsequent future. + /// + /// The provided closure `f` will only be called if this future is resolved + /// to an [`Ok`]. If this future resolves to an [`Err`], panics, or is + /// dropped, then the provided closure will never be invoked. The + /// [`Error`](TryFuture::Error) type of this future and the future + /// returned by `f` have to match. + /// + /// Note that this method consumes the future it is called on and returns a + /// wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Ok::<i32, i32>(1) }; + /// let future = future.and_then(|x| async move { Ok::<i32, i32>(x + 3) }); + /// assert_eq!(future.await, Ok(4)); + /// # }); + /// ``` + /// + /// Calling [`and_then`](TryFutureExt::and_then) on an errored future has no + /// effect: + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Err::<i32, i32>(1) }; + /// let future = future.and_then(|x| async move { Err::<i32, i32>(x + 3) }); + /// assert_eq!(future.await, Err(1)); + /// # }); + /// ``` + fn and_then<Fut, F>(self, f: F) -> AndThen<Self, Fut, F> + where + F: FnOnce(Self::Ok) -> Fut, + Fut: TryFuture<Error = Self::Error>, + Self: Sized, + { + assert_future::<Result<Fut::Ok, Fut::Error>, _>(AndThen::new(self, f)) + } + + /// Executes another future if this one resolves to an error. The + /// error value is passed to a closure to create this subsequent future. + /// + /// The provided closure `f` will only be called if this future is resolved + /// to an [`Err`]. If this future resolves to an [`Ok`], panics, or is + /// dropped, then the provided closure will never be invoked. The + /// [`Ok`](TryFuture::Ok) type of this future and the future returned by `f` + /// have to match. + /// + /// Note that this method consumes the future it is called on and returns a + /// wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Err::<i32, i32>(1) }; + /// let future = future.or_else(|x| async move { Err::<i32, i32>(x + 3) }); + /// assert_eq!(future.await, Err(4)); + /// # }); + /// ``` + /// + /// Calling [`or_else`](TryFutureExt::or_else) on a successful future has + /// no effect: + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Ok::<i32, i32>(1) }; + /// let future = future.or_else(|x| async move { Ok::<i32, i32>(x + 3) }); + /// assert_eq!(future.await, Ok(1)); + /// # }); + /// ``` + fn or_else<Fut, F>(self, f: F) -> OrElse<Self, Fut, F> + where + F: FnOnce(Self::Error) -> Fut, + Fut: TryFuture<Ok = Self::Ok>, + Self: Sized, + { + assert_future::<Result<Fut::Ok, Fut::Error>, _>(OrElse::new(self, f)) + } + + /// Do something with the success value of a future before passing it on. + /// + /// When using futures, you'll often chain several of them together. While + /// working on such code, you might want to check out what's happening at + /// various parts in the pipeline, without consuming the intermediate + /// value. To do that, insert a call to `inspect_ok`. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::TryFutureExt; + /// + /// let future = async { Ok::<_, ()>(1) }; + /// let new_future = future.inspect_ok(|&x| println!("about to resolve: {}", x)); + /// assert_eq!(new_future.await, Ok(1)); + /// # }); + /// ``` + fn inspect_ok<F>(self, f: F) -> InspectOk<Self, F> + where + F: FnOnce(&Self::Ok), + Self: Sized, + { + assert_future::<Result<Self::Ok, Self::Error>, _>(InspectOk::new(self, f)) + } + + /// Do something with the error value of a future before passing it on. + /// + /// When using futures, you'll often chain several of them together. While + /// working on such code, you might want to check out what's happening at + /// various parts in the pipeline, without consuming the intermediate + /// value. To do that, insert a call to `inspect_err`. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::TryFutureExt; + /// + /// let future = async { Err::<(), _>(1) }; + /// let new_future = future.inspect_err(|&x| println!("about to error: {}", x)); + /// assert_eq!(new_future.await, Err(1)); + /// # }); + /// ``` + fn inspect_err<F>(self, f: F) -> InspectErr<Self, F> + where + F: FnOnce(&Self::Error), + Self: Sized, + { + assert_future::<Result<Self::Ok, Self::Error>, _>(InspectErr::new(self, f)) + } + + /// Flatten the execution of this future when the successful result of this + /// future is another future. + /// + /// This is equivalent to `future.and_then(|x| x)`. + fn try_flatten(self) -> TryFlatten<Self, Self::Ok> + where + Self::Ok: TryFuture<Error = Self::Error>, + Self: Sized, + { + assert_future::<Result<<Self::Ok as TryFuture>::Ok, Self::Error>, _>(TryFlatten::new(self)) + } + + /// Flatten the execution of this future when the successful result of this + /// future is a stream. + /// + /// This can be useful when stream initialization is deferred, and it is + /// convenient to work with that stream as if stream was available at the + /// call site. + /// + /// Note that this function consumes this future and returns a wrapped + /// version of it. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future::TryFutureExt; + /// use futures::stream::{self, TryStreamExt}; + /// + /// let stream_items = vec![17, 18, 19].into_iter().map(Ok); + /// let future_of_a_stream = async { Ok::<_, ()>(stream::iter(stream_items)) }; + /// + /// let stream = future_of_a_stream.try_flatten_stream(); + /// let list = stream.try_collect::<Vec<_>>().await; + /// assert_eq!(list, Ok(vec![17, 18, 19])); + /// # }); + /// ``` + fn try_flatten_stream(self) -> TryFlattenStream<Self> + where + Self::Ok: TryStream<Error = Self::Error>, + Self: Sized, + { + assert_stream::<Result<<Self::Ok as TryStream>::Ok, Self::Error>, _>(TryFlattenStream::new( + self, + )) + } + + /// Unwraps this future's output, producing a future with this future's + /// [`Ok`](TryFuture::Ok) type as its + /// [`Output`](std::future::Future::Output) type. + /// + /// If this future is resolved successfully, the returned future will + /// contain the original future's success value as output. Otherwise, the + /// closure `f` is called with the error value to produce an alternate + /// success value. + /// + /// This method is similar to the [`Result::unwrap_or_else`] method. + /// + /// # Examples + /// + /// ``` + /// use futures::future::TryFutureExt; + /// + /// # futures::executor::block_on(async { + /// let future = async { Err::<(), &str>("Boom!") }; + /// let future = future.unwrap_or_else(|_| ()); + /// assert_eq!(future.await, ()); + /// # }); + /// ``` + fn unwrap_or_else<F>(self, f: F) -> UnwrapOrElse<Self, F> + where + Self: Sized, + F: FnOnce(Self::Error) -> Self::Ok, + { + assert_future::<Self::Ok, _>(UnwrapOrElse::new(self, f)) + } + + /// Wraps a [`TryFuture`] into a future compatible with libraries using + /// futures 0.1 future definitions. Requires the `compat` feature to enable. + #[cfg(feature = "compat")] + #[cfg_attr(docsrs, doc(cfg(feature = "compat")))] + fn compat(self) -> Compat<Self> + where + Self: Sized + Unpin, + { + Compat::new(self) + } + + /// Wraps a [`TryFuture`] into a type that implements + /// [`Future`](std::future::Future). + /// + /// [`TryFuture`]s currently do not implement the + /// [`Future`](std::future::Future) trait due to limitations of the + /// compiler. + /// + /// # Examples + /// + /// ``` + /// use futures::future::{Future, TryFuture, TryFutureExt}; + /// + /// # type T = i32; + /// # type E = (); + /// fn make_try_future() -> impl TryFuture<Ok = T, Error = E> { // ... } + /// # async { Ok::<i32, ()>(1) } + /// # } + /// fn take_future(future: impl Future<Output = Result<T, E>>) { /* ... */ } + /// + /// take_future(make_try_future().into_future()); + /// ``` + fn into_future(self) -> IntoFuture<Self> + where + Self: Sized, + { + assert_future::<Result<Self::Ok, Self::Error>, _>(IntoFuture::new(self)) + } + + /// A convenience method for calling [`TryFuture::try_poll`] on [`Unpin`] + /// future types. + fn try_poll_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Result<Self::Ok, Self::Error>> + where + Self: Unpin, + { + Pin::new(self).try_poll(cx) + } +} diff --git a/third_party/rust/futures-util/src/future/try_future/try_flatten.rs b/third_party/rust/futures-util/src/future/try_future/try_flatten.rs new file mode 100644 index 0000000000..1ce4559ac2 --- /dev/null +++ b/third_party/rust/futures-util/src/future/try_future/try_flatten.rs @@ -0,0 +1,162 @@ +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future, TryFuture}; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + #[project = TryFlattenProj] + #[derive(Debug)] + pub enum TryFlatten<Fut1, Fut2> { + First { #[pin] f: Fut1 }, + Second { #[pin] f: Fut2 }, + Empty, + } +} + +impl<Fut1, Fut2> TryFlatten<Fut1, Fut2> { + pub(crate) fn new(future: Fut1) -> Self { + Self::First { f: future } + } +} + +impl<Fut> FusedFuture for TryFlatten<Fut, Fut::Ok> +where + Fut: TryFuture, + Fut::Ok: TryFuture<Error = Fut::Error>, +{ + fn is_terminated(&self) -> bool { + match self { + Self::Empty => true, + _ => false, + } + } +} + +impl<Fut> Future for TryFlatten<Fut, Fut::Ok> +where + Fut: TryFuture, + Fut::Ok: TryFuture<Error = Fut::Error>, +{ + type Output = Result<<Fut::Ok as TryFuture>::Ok, Fut::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + Poll::Ready(loop { + match self.as_mut().project() { + TryFlattenProj::First { f } => match ready!(f.try_poll(cx)) { + Ok(f) => self.set(Self::Second { f }), + Err(e) => { + self.set(Self::Empty); + break Err(e); + } + }, + TryFlattenProj::Second { f } => { + let output = ready!(f.try_poll(cx)); + self.set(Self::Empty); + break output; + } + TryFlattenProj::Empty => panic!("TryFlatten polled after completion"), + } + }) + } +} + +impl<Fut> FusedStream for TryFlatten<Fut, Fut::Ok> +where + Fut: TryFuture, + Fut::Ok: TryStream<Error = Fut::Error>, +{ + fn is_terminated(&self) -> bool { + match self { + Self::Empty => true, + _ => false, + } + } +} + +impl<Fut> Stream for TryFlatten<Fut, Fut::Ok> +where + Fut: TryFuture, + Fut::Ok: TryStream<Error = Fut::Error>, +{ + type Item = Result<<Fut::Ok as TryStream>::Ok, Fut::Error>; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + Poll::Ready(loop { + match self.as_mut().project() { + TryFlattenProj::First { f } => match ready!(f.try_poll(cx)) { + Ok(f) => self.set(Self::Second { f }), + Err(e) => { + self.set(Self::Empty); + break Some(Err(e)); + } + }, + TryFlattenProj::Second { f } => { + let output = ready!(f.try_poll_next(cx)); + if output.is_none() { + self.set(Self::Empty); + } + break output; + } + TryFlattenProj::Empty => break None, + } + }) + } +} + +#[cfg(feature = "sink")] +impl<Fut, Item> Sink<Item> for TryFlatten<Fut, Fut::Ok> +where + Fut: TryFuture, + Fut::Ok: Sink<Item, Error = Fut::Error>, +{ + type Error = Fut::Error; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + Poll::Ready(loop { + match self.as_mut().project() { + TryFlattenProj::First { f } => match ready!(f.try_poll(cx)) { + Ok(f) => self.set(Self::Second { f }), + Err(e) => { + self.set(Self::Empty); + break Err(e); + } + }, + TryFlattenProj::Second { f } => { + break ready!(f.poll_ready(cx)); + } + TryFlattenProj::Empty => panic!("poll_ready called after eof"), + } + }) + } + + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + match self.project() { + TryFlattenProj::First { .. } => panic!("poll_ready not called first"), + TryFlattenProj::Second { f } => f.start_send(item), + TryFlattenProj::Empty => panic!("start_send called after eof"), + } + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + match self.project() { + TryFlattenProj::First { .. } => Poll::Ready(Ok(())), + TryFlattenProj::Second { f } => f.poll_flush(cx), + TryFlattenProj::Empty => panic!("poll_flush called after eof"), + } + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + let res = match self.as_mut().project() { + TryFlattenProj::Second { f } => f.poll_close(cx), + _ => Poll::Ready(Ok(())), + }; + if res.is_ready() { + self.set(Self::Empty); + } + res + } +} diff --git a/third_party/rust/futures-util/src/future/try_future/try_flatten_err.rs b/third_party/rust/futures-util/src/future/try_future/try_flatten_err.rs new file mode 100644 index 0000000000..39b7d9f5f6 --- /dev/null +++ b/third_party/rust/futures-util/src/future/try_future/try_flatten_err.rs @@ -0,0 +1,62 @@ +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future, TryFuture}; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + #[project = TryFlattenErrProj] + #[derive(Debug)] + pub enum TryFlattenErr<Fut1, Fut2> { + First { #[pin] f: Fut1 }, + Second { #[pin] f: Fut2 }, + Empty, + } +} + +impl<Fut1, Fut2> TryFlattenErr<Fut1, Fut2> { + pub(crate) fn new(future: Fut1) -> Self { + Self::First { f: future } + } +} + +impl<Fut> FusedFuture for TryFlattenErr<Fut, Fut::Error> +where + Fut: TryFuture, + Fut::Error: TryFuture<Ok = Fut::Ok>, +{ + fn is_terminated(&self) -> bool { + match self { + Self::Empty => true, + _ => false, + } + } +} + +impl<Fut> Future for TryFlattenErr<Fut, Fut::Error> +where + Fut: TryFuture, + Fut::Error: TryFuture<Ok = Fut::Ok>, +{ + type Output = Result<Fut::Ok, <Fut::Error as TryFuture>::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + Poll::Ready(loop { + match self.as_mut().project() { + TryFlattenErrProj::First { f } => match ready!(f.try_poll(cx)) { + Err(f) => self.set(Self::Second { f }), + Ok(e) => { + self.set(Self::Empty); + break Ok(e); + } + }, + TryFlattenErrProj::Second { f } => { + let output = ready!(f.try_poll(cx)); + self.set(Self::Empty); + break output; + } + TryFlattenErrProj::Empty => panic!("TryFlattenErr polled after completion"), + } + }) + } +} diff --git a/third_party/rust/futures-util/src/future/try_join.rs b/third_party/rust/futures-util/src/future/try_join.rs new file mode 100644 index 0000000000..6af1f0ccbf --- /dev/null +++ b/third_party/rust/futures-util/src/future/try_join.rs @@ -0,0 +1,256 @@ +#![allow(non_snake_case)] + +use crate::future::{assert_future, try_maybe_done, TryMaybeDone}; +use core::fmt; +use core::pin::Pin; +use futures_core::future::{Future, TryFuture}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +macro_rules! generate { + ($( + $(#[$doc:meta])* + ($Join:ident, <Fut1, $($Fut:ident),*>), + )*) => ($( + pin_project! { + $(#[$doc])* + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct $Join<Fut1: TryFuture, $($Fut: TryFuture),*> { + #[pin] Fut1: TryMaybeDone<Fut1>, + $(#[pin] $Fut: TryMaybeDone<$Fut>,)* + } + } + + impl<Fut1, $($Fut),*> fmt::Debug for $Join<Fut1, $($Fut),*> + where + Fut1: TryFuture + fmt::Debug, + Fut1::Ok: fmt::Debug, + Fut1::Error: fmt::Debug, + $( + $Fut: TryFuture + fmt::Debug, + $Fut::Ok: fmt::Debug, + $Fut::Error: fmt::Debug, + )* + { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct(stringify!($Join)) + .field("Fut1", &self.Fut1) + $(.field(stringify!($Fut), &self.$Fut))* + .finish() + } + } + + impl<Fut1, $($Fut),*> $Join<Fut1, $($Fut),*> + where + Fut1: TryFuture, + $( + $Fut: TryFuture<Error=Fut1::Error> + ),* + { + fn new(Fut1: Fut1, $($Fut: $Fut),*) -> Self { + Self { + Fut1: try_maybe_done(Fut1), + $($Fut: try_maybe_done($Fut)),* + } + } + } + + impl<Fut1, $($Fut),*> Future for $Join<Fut1, $($Fut),*> + where + Fut1: TryFuture, + $( + $Fut: TryFuture<Error=Fut1::Error> + ),* + { + type Output = Result<(Fut1::Ok, $($Fut::Ok),*), Fut1::Error>; + + fn poll( + self: Pin<&mut Self>, cx: &mut Context<'_> + ) -> Poll<Self::Output> { + let mut all_done = true; + let mut futures = self.project(); + all_done &= futures.Fut1.as_mut().poll(cx)?.is_ready(); + $( + all_done &= futures.$Fut.as_mut().poll(cx)?.is_ready(); + )* + + if all_done { + Poll::Ready(Ok(( + futures.Fut1.take_output().unwrap(), + $( + futures.$Fut.take_output().unwrap() + ),* + ))) + } else { + Poll::Pending + } + } + } + )*) +} + +generate! { + /// Future for the [`try_join`](try_join()) function. + (TryJoin, <Fut1, Fut2>), + + /// Future for the [`try_join3`] function. + (TryJoin3, <Fut1, Fut2, Fut3>), + + /// Future for the [`try_join4`] function. + (TryJoin4, <Fut1, Fut2, Fut3, Fut4>), + + /// Future for the [`try_join5`] function. + (TryJoin5, <Fut1, Fut2, Fut3, Fut4, Fut5>), +} + +/// Joins the result of two futures, waiting for them both to complete or +/// for one to produce an error. +/// +/// This function will return a new future which awaits both futures to +/// complete. If successful, the returned future will finish with a tuple of +/// both results. If unsuccessful, it will complete with the first error +/// encountered. +/// +/// Note that this function consumes the passed futures and returns a +/// wrapped version of it. +/// +/// # Examples +/// +/// When used on multiple futures that return [`Ok`], `try_join` will return +/// [`Ok`] of a tuple of the values: +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Ok::<i32, i32>(2)); +/// let pair = future::try_join(a, b); +/// +/// assert_eq!(pair.await, Ok((1, 2))); +/// # }); +/// ``` +/// +/// If one of the futures resolves to an error, `try_join` will return +/// that error: +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Err::<i32, i32>(2)); +/// let pair = future::try_join(a, b); +/// +/// assert_eq!(pair.await, Err(2)); +/// # }); +/// ``` +pub fn try_join<Fut1, Fut2>(future1: Fut1, future2: Fut2) -> TryJoin<Fut1, Fut2> +where + Fut1: TryFuture, + Fut2: TryFuture<Error = Fut1::Error>, +{ + assert_future::<Result<(Fut1::Ok, Fut2::Ok), Fut1::Error>, _>(TryJoin::new(future1, future2)) +} + +/// Same as [`try_join`](try_join()), but with more futures. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Ok::<i32, i32>(2)); +/// let c = future::ready(Ok::<i32, i32>(3)); +/// let tuple = future::try_join3(a, b, c); +/// +/// assert_eq!(tuple.await, Ok((1, 2, 3))); +/// # }); +/// ``` +pub fn try_join3<Fut1, Fut2, Fut3>( + future1: Fut1, + future2: Fut2, + future3: Fut3, +) -> TryJoin3<Fut1, Fut2, Fut3> +where + Fut1: TryFuture, + Fut2: TryFuture<Error = Fut1::Error>, + Fut3: TryFuture<Error = Fut1::Error>, +{ + assert_future::<Result<(Fut1::Ok, Fut2::Ok, Fut3::Ok), Fut1::Error>, _>(TryJoin3::new( + future1, future2, future3, + )) +} + +/// Same as [`try_join`](try_join()), but with more futures. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Ok::<i32, i32>(2)); +/// let c = future::ready(Ok::<i32, i32>(3)); +/// let d = future::ready(Ok::<i32, i32>(4)); +/// let tuple = future::try_join4(a, b, c, d); +/// +/// assert_eq!(tuple.await, Ok((1, 2, 3, 4))); +/// # }); +/// ``` +pub fn try_join4<Fut1, Fut2, Fut3, Fut4>( + future1: Fut1, + future2: Fut2, + future3: Fut3, + future4: Fut4, +) -> TryJoin4<Fut1, Fut2, Fut3, Fut4> +where + Fut1: TryFuture, + Fut2: TryFuture<Error = Fut1::Error>, + Fut3: TryFuture<Error = Fut1::Error>, + Fut4: TryFuture<Error = Fut1::Error>, +{ + assert_future::<Result<(Fut1::Ok, Fut2::Ok, Fut3::Ok, Fut4::Ok), Fut1::Error>, _>( + TryJoin4::new(future1, future2, future3, future4), + ) +} + +/// Same as [`try_join`](try_join()), but with more futures. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future; +/// +/// let a = future::ready(Ok::<i32, i32>(1)); +/// let b = future::ready(Ok::<i32, i32>(2)); +/// let c = future::ready(Ok::<i32, i32>(3)); +/// let d = future::ready(Ok::<i32, i32>(4)); +/// let e = future::ready(Ok::<i32, i32>(5)); +/// let tuple = future::try_join5(a, b, c, d, e); +/// +/// assert_eq!(tuple.await, Ok((1, 2, 3, 4, 5))); +/// # }); +/// ``` +pub fn try_join5<Fut1, Fut2, Fut3, Fut4, Fut5>( + future1: Fut1, + future2: Fut2, + future3: Fut3, + future4: Fut4, + future5: Fut5, +) -> TryJoin5<Fut1, Fut2, Fut3, Fut4, Fut5> +where + Fut1: TryFuture, + Fut2: TryFuture<Error = Fut1::Error>, + Fut3: TryFuture<Error = Fut1::Error>, + Fut4: TryFuture<Error = Fut1::Error>, + Fut5: TryFuture<Error = Fut1::Error>, +{ + assert_future::<Result<(Fut1::Ok, Fut2::Ok, Fut3::Ok, Fut4::Ok, Fut5::Ok), Fut1::Error>, _>( + TryJoin5::new(future1, future2, future3, future4, future5), + ) +} diff --git a/third_party/rust/futures-util/src/future/try_join_all.rs b/third_party/rust/futures-util/src/future/try_join_all.rs new file mode 100644 index 0000000000..506f450657 --- /dev/null +++ b/third_party/rust/futures-util/src/future/try_join_all.rs @@ -0,0 +1,200 @@ +//! Definition of the `TryJoinAll` combinator, waiting for all of a list of +//! futures to finish with either success or error. + +use alloc::boxed::Box; +use alloc::vec::Vec; +use core::fmt; +use core::future::Future; +use core::iter::FromIterator; +use core::mem; +use core::pin::Pin; +use core::task::{Context, Poll}; + +use super::{assert_future, join_all, IntoFuture, TryFuture, TryMaybeDone}; + +#[cfg(not(futures_no_atomic_cas))] +use crate::stream::{FuturesOrdered, TryCollect, TryStreamExt}; +use crate::TryFutureExt; + +enum FinalState<E = ()> { + Pending, + AllDone, + Error(E), +} + +/// Future for the [`try_join_all`] function. +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct TryJoinAll<F> +where + F: TryFuture, +{ + kind: TryJoinAllKind<F>, +} + +enum TryJoinAllKind<F> +where + F: TryFuture, +{ + Small { + elems: Pin<Box<[TryMaybeDone<IntoFuture<F>>]>>, + }, + #[cfg(not(futures_no_atomic_cas))] + Big { + fut: TryCollect<FuturesOrdered<IntoFuture<F>>, Vec<F::Ok>>, + }, +} + +impl<F> fmt::Debug for TryJoinAll<F> +where + F: TryFuture + fmt::Debug, + F::Ok: fmt::Debug, + F::Error: fmt::Debug, + F::Output: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self.kind { + TryJoinAllKind::Small { ref elems } => { + f.debug_struct("TryJoinAll").field("elems", elems).finish() + } + #[cfg(not(futures_no_atomic_cas))] + TryJoinAllKind::Big { ref fut, .. } => fmt::Debug::fmt(fut, f), + } + } +} + +/// Creates a future which represents either a collection of the results of the +/// futures given or an error. +/// +/// The returned future will drive execution for all of its underlying futures, +/// collecting the results into a destination `Vec<T>` in the same order as they +/// were provided. +/// +/// If any future returns an error then all other futures will be canceled and +/// an error will be returned immediately. If all futures complete successfully, +/// however, then the returned future will succeed with a `Vec` of all the +/// successful results. +/// +/// This function is only available when the `std` or `alloc` feature of this +/// library is activated, and it is activated by default. +/// +/// # See Also +/// +/// `try_join_all` will switch to the more powerful [`FuturesOrdered`] for performance +/// reasons if the number of futures is large. You may want to look into using it or +/// it's counterpart [`FuturesUnordered`][crate::stream::FuturesUnordered] directly. +/// +/// Some examples for additional functionality provided by these are: +/// +/// * Adding new futures to the set even after it has been started. +/// +/// * Only polling the specific futures that have been woken. In cases where +/// you have a lot of futures this will result in much more efficient polling. +/// +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::future::{self, try_join_all}; +/// +/// let futures = vec![ +/// future::ok::<u32, u32>(1), +/// future::ok::<u32, u32>(2), +/// future::ok::<u32, u32>(3), +/// ]; +/// +/// assert_eq!(try_join_all(futures).await, Ok(vec![1, 2, 3])); +/// +/// let futures = vec![ +/// future::ok::<u32, u32>(1), +/// future::err::<u32, u32>(2), +/// future::ok::<u32, u32>(3), +/// ]; +/// +/// assert_eq!(try_join_all(futures).await, Err(2)); +/// # }); +/// ``` +pub fn try_join_all<I>(iter: I) -> TryJoinAll<I::Item> +where + I: IntoIterator, + I::Item: TryFuture, +{ + let iter = iter.into_iter().map(TryFutureExt::into_future); + + #[cfg(futures_no_atomic_cas)] + { + let kind = TryJoinAllKind::Small { + elems: iter.map(TryMaybeDone::Future).collect::<Box<[_]>>().into(), + }; + + assert_future::<Result<Vec<<I::Item as TryFuture>::Ok>, <I::Item as TryFuture>::Error>, _>( + TryJoinAll { kind }, + ) + } + + #[cfg(not(futures_no_atomic_cas))] + { + let kind = match iter.size_hint().1 { + Some(max) if max <= join_all::SMALL => TryJoinAllKind::Small { + elems: iter.map(TryMaybeDone::Future).collect::<Box<[_]>>().into(), + }, + _ => TryJoinAllKind::Big { fut: iter.collect::<FuturesOrdered<_>>().try_collect() }, + }; + + assert_future::<Result<Vec<<I::Item as TryFuture>::Ok>, <I::Item as TryFuture>::Error>, _>( + TryJoinAll { kind }, + ) + } +} + +impl<F> Future for TryJoinAll<F> +where + F: TryFuture, +{ + type Output = Result<Vec<F::Ok>, F::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + match &mut self.kind { + TryJoinAllKind::Small { elems } => { + let mut state = FinalState::AllDone; + + for elem in join_all::iter_pin_mut(elems.as_mut()) { + match elem.try_poll(cx) { + Poll::Pending => state = FinalState::Pending, + Poll::Ready(Ok(())) => {} + Poll::Ready(Err(e)) => { + state = FinalState::Error(e); + break; + } + } + } + + match state { + FinalState::Pending => Poll::Pending, + FinalState::AllDone => { + let mut elems = mem::replace(elems, Box::pin([])); + let results = join_all::iter_pin_mut(elems.as_mut()) + .map(|e| e.take_output().unwrap()) + .collect(); + Poll::Ready(Ok(results)) + } + FinalState::Error(e) => { + let _ = mem::replace(elems, Box::pin([])); + Poll::Ready(Err(e)) + } + } + } + #[cfg(not(futures_no_atomic_cas))] + TryJoinAllKind::Big { fut } => Pin::new(fut).poll(cx), + } + } +} + +impl<F> FromIterator<F> for TryJoinAll<F> +where + F: TryFuture, +{ + fn from_iter<T: IntoIterator<Item = F>>(iter: T) -> Self { + try_join_all(iter) + } +} diff --git a/third_party/rust/futures-util/src/future/try_maybe_done.rs b/third_party/rust/futures-util/src/future/try_maybe_done.rs new file mode 100644 index 0000000000..24044d2c27 --- /dev/null +++ b/third_party/rust/futures-util/src/future/try_maybe_done.rs @@ -0,0 +1,92 @@ +//! Definition of the TryMaybeDone combinator + +use super::assert_future; +use core::mem; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future, TryFuture}; +use futures_core::ready; +use futures_core::task::{Context, Poll}; + +/// A future that may have completed with an error. +/// +/// This is created by the [`try_maybe_done()`] function. +#[derive(Debug)] +pub enum TryMaybeDone<Fut: TryFuture> { + /// A not-yet-completed future + Future(/* #[pin] */ Fut), + /// The output of the completed future + Done(Fut::Ok), + /// The empty variant after the result of a [`TryMaybeDone`] has been + /// taken using the [`take_output`](TryMaybeDone::take_output) method, + /// or if the future returned an error. + Gone, +} + +impl<Fut: TryFuture + Unpin> Unpin for TryMaybeDone<Fut> {} + +/// Wraps a future into a `TryMaybeDone` +pub fn try_maybe_done<Fut: TryFuture>(future: Fut) -> TryMaybeDone<Fut> { + assert_future::<Result<(), Fut::Error>, _>(TryMaybeDone::Future(future)) +} + +impl<Fut: TryFuture> TryMaybeDone<Fut> { + /// Returns an [`Option`] containing a mutable reference to the output of the future. + /// The output of this method will be [`Some`] if and only if the inner + /// future has completed successfully and [`take_output`](TryMaybeDone::take_output) + /// has not yet been called. + #[inline] + pub fn output_mut(self: Pin<&mut Self>) -> Option<&mut Fut::Ok> { + unsafe { + match self.get_unchecked_mut() { + TryMaybeDone::Done(res) => Some(res), + _ => None, + } + } + } + + /// Attempt to take the output of a `TryMaybeDone` without driving it + /// towards completion. + #[inline] + pub fn take_output(self: Pin<&mut Self>) -> Option<Fut::Ok> { + match &*self { + Self::Done(_) => {} + Self::Future(_) | Self::Gone => return None, + } + unsafe { + match mem::replace(self.get_unchecked_mut(), Self::Gone) { + TryMaybeDone::Done(output) => Some(output), + _ => unreachable!(), + } + } + } +} + +impl<Fut: TryFuture> FusedFuture for TryMaybeDone<Fut> { + fn is_terminated(&self) -> bool { + match self { + Self::Future(_) => false, + Self::Done(_) | Self::Gone => true, + } + } +} + +impl<Fut: TryFuture> Future for TryMaybeDone<Fut> { + type Output = Result<(), Fut::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + unsafe { + match self.as_mut().get_unchecked_mut() { + TryMaybeDone::Future(f) => match ready!(Pin::new_unchecked(f).try_poll(cx)) { + Ok(res) => self.set(Self::Done(res)), + Err(e) => { + self.set(Self::Gone); + return Poll::Ready(Err(e)); + } + }, + TryMaybeDone::Done(_) => {} + TryMaybeDone::Gone => panic!("TryMaybeDone polled after value taken"), + } + } + Poll::Ready(Ok(())) + } +} diff --git a/third_party/rust/futures-util/src/future/try_select.rs b/third_party/rust/futures-util/src/future/try_select.rs new file mode 100644 index 0000000000..4d0b7ff135 --- /dev/null +++ b/third_party/rust/futures-util/src/future/try_select.rs @@ -0,0 +1,84 @@ +use crate::future::{Either, TryFutureExt}; +use core::pin::Pin; +use futures_core::future::{Future, TryFuture}; +use futures_core::task::{Context, Poll}; + +/// Future for the [`try_select()`] function. +#[must_use = "futures do nothing unless you `.await` or poll them"] +#[derive(Debug)] +pub struct TrySelect<A, B> { + inner: Option<(A, B)>, +} + +impl<A: Unpin, B: Unpin> Unpin for TrySelect<A, B> {} + +/// Waits for either one of two differently-typed futures to complete. +/// +/// This function will return a new future which awaits for either one of both +/// futures to complete. The returned future will finish with both the value +/// resolved and a future representing the completion of the other work. +/// +/// Note that this function consumes the receiving futures and returns a +/// wrapped version of them. +/// +/// Also note that if both this and the second future have the same +/// success/error type you can use the `Either::factor_first` method to +/// conveniently extract out the value at the end. +/// +/// # Examples +/// +/// ``` +/// use futures::future::{self, Either, Future, FutureExt, TryFuture, TryFutureExt}; +/// +/// // A poor-man's try_join implemented on top of select +/// +/// fn try_join<A, B, E>(a: A, b: B) -> impl TryFuture<Ok=(A::Ok, B::Ok), Error=E> +/// where A: TryFuture<Error = E> + Unpin + 'static, +/// B: TryFuture<Error = E> + Unpin + 'static, +/// E: 'static, +/// { +/// future::try_select(a, b).then(|res| -> Box<dyn Future<Output = Result<_, _>> + Unpin> { +/// match res { +/// Ok(Either::Left((x, b))) => Box::new(b.map_ok(move |y| (x, y))), +/// Ok(Either::Right((y, a))) => Box::new(a.map_ok(move |x| (x, y))), +/// Err(Either::Left((e, _))) => Box::new(future::err(e)), +/// Err(Either::Right((e, _))) => Box::new(future::err(e)), +/// } +/// }) +/// } +/// ``` +pub fn try_select<A, B>(future1: A, future2: B) -> TrySelect<A, B> +where + A: TryFuture + Unpin, + B: TryFuture + Unpin, +{ + super::assert_future::< + Result<Either<(A::Ok, B), (B::Ok, A)>, Either<(A::Error, B), (B::Error, A)>>, + _, + >(TrySelect { inner: Some((future1, future2)) }) +} + +impl<A: Unpin, B: Unpin> Future for TrySelect<A, B> +where + A: TryFuture, + B: TryFuture, +{ + #[allow(clippy::type_complexity)] + type Output = Result<Either<(A::Ok, B), (B::Ok, A)>, Either<(A::Error, B), (B::Error, A)>>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let (mut a, mut b) = self.inner.take().expect("cannot poll Select twice"); + match a.try_poll_unpin(cx) { + Poll::Ready(Err(x)) => Poll::Ready(Err(Either::Left((x, b)))), + Poll::Ready(Ok(x)) => Poll::Ready(Ok(Either::Left((x, b)))), + Poll::Pending => match b.try_poll_unpin(cx) { + Poll::Ready(Err(x)) => Poll::Ready(Err(Either::Right((x, a)))), + Poll::Ready(Ok(x)) => Poll::Ready(Ok(Either::Right((x, a)))), + Poll::Pending => { + self.inner = Some((a, b)); + Poll::Pending + } + }, + } + } +} diff --git a/third_party/rust/futures-util/src/io/allow_std.rs b/third_party/rust/futures-util/src/io/allow_std.rs new file mode 100644 index 0000000000..ec30ee31e5 --- /dev/null +++ b/third_party/rust/futures-util/src/io/allow_std.rs @@ -0,0 +1,200 @@ +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, IoSlice, IoSliceMut, SeekFrom}; +use std::pin::Pin; +use std::{fmt, io}; + +/// A simple wrapper type which allows types which implement only +/// implement `std::io::Read` or `std::io::Write` +/// to be used in contexts which expect an `AsyncRead` or `AsyncWrite`. +/// +/// If these types issue an error with the kind `io::ErrorKind::WouldBlock`, +/// it is expected that they will notify the current task on readiness. +/// Synchronous `std` types should not issue errors of this kind and +/// are safe to use in this context. However, using these types with +/// `AllowStdIo` will cause the event loop to block, so they should be used +/// with care. +#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)] +pub struct AllowStdIo<T>(T); + +impl<T> Unpin for AllowStdIo<T> {} + +macro_rules! try_with_interrupt { + ($e:expr) => { + loop { + match $e { + Ok(e) => { + break e; + } + Err(ref e) if e.kind() == ::std::io::ErrorKind::Interrupted => { + continue; + } + Err(e) => { + return Poll::Ready(Err(e)); + } + } + } + }; +} + +impl<T> AllowStdIo<T> { + /// Creates a new `AllowStdIo` from an existing IO object. + pub fn new(io: T) -> Self { + Self(io) + } + + /// Returns a reference to the contained IO object. + pub fn get_ref(&self) -> &T { + &self.0 + } + + /// Returns a mutable reference to the contained IO object. + pub fn get_mut(&mut self) -> &mut T { + &mut self.0 + } + + /// Consumes self and returns the contained IO object. + pub fn into_inner(self) -> T { + self.0 + } +} + +impl<T> io::Write for AllowStdIo<T> +where + T: io::Write, +{ + fn write(&mut self, buf: &[u8]) -> io::Result<usize> { + self.0.write(buf) + } + fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { + self.0.write_vectored(bufs) + } + fn flush(&mut self) -> io::Result<()> { + self.0.flush() + } + fn write_all(&mut self, buf: &[u8]) -> io::Result<()> { + self.0.write_all(buf) + } + fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> io::Result<()> { + self.0.write_fmt(fmt) + } +} + +impl<T> AsyncWrite for AllowStdIo<T> +where + T: io::Write, +{ + fn poll_write( + mut self: Pin<&mut Self>, + _: &mut Context<'_>, + buf: &[u8], + ) -> Poll<io::Result<usize>> { + Poll::Ready(Ok(try_with_interrupt!(self.0.write(buf)))) + } + + fn poll_write_vectored( + mut self: Pin<&mut Self>, + _: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<io::Result<usize>> { + Poll::Ready(Ok(try_with_interrupt!(self.0.write_vectored(bufs)))) + } + + fn poll_flush(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> { + try_with_interrupt!(self.0.flush()); + Poll::Ready(Ok(())) + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + self.poll_flush(cx) + } +} + +impl<T> io::Read for AllowStdIo<T> +where + T: io::Read, +{ + fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { + self.0.read(buf) + } + fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> { + self.0.read_vectored(bufs) + } + fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> { + self.0.read_to_end(buf) + } + fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> { + self.0.read_to_string(buf) + } + fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> { + self.0.read_exact(buf) + } +} + +impl<T> AsyncRead for AllowStdIo<T> +where + T: io::Read, +{ + fn poll_read( + mut self: Pin<&mut Self>, + _: &mut Context<'_>, + buf: &mut [u8], + ) -> Poll<io::Result<usize>> { + Poll::Ready(Ok(try_with_interrupt!(self.0.read(buf)))) + } + + fn poll_read_vectored( + mut self: Pin<&mut Self>, + _: &mut Context<'_>, + bufs: &mut [IoSliceMut<'_>], + ) -> Poll<io::Result<usize>> { + Poll::Ready(Ok(try_with_interrupt!(self.0.read_vectored(bufs)))) + } +} + +impl<T> io::Seek for AllowStdIo<T> +where + T: io::Seek, +{ + fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { + self.0.seek(pos) + } +} + +impl<T> AsyncSeek for AllowStdIo<T> +where + T: io::Seek, +{ + fn poll_seek( + mut self: Pin<&mut Self>, + _: &mut Context<'_>, + pos: SeekFrom, + ) -> Poll<io::Result<u64>> { + Poll::Ready(Ok(try_with_interrupt!(self.0.seek(pos)))) + } +} + +impl<T> io::BufRead for AllowStdIo<T> +where + T: io::BufRead, +{ + fn fill_buf(&mut self) -> io::Result<&[u8]> { + self.0.fill_buf() + } + fn consume(&mut self, amt: usize) { + self.0.consume(amt) + } +} + +impl<T> AsyncBufRead for AllowStdIo<T> +where + T: io::BufRead, +{ + fn poll_fill_buf(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<&[u8]>> { + let this: *mut Self = &mut *self as *mut _; + Poll::Ready(Ok(try_with_interrupt!(unsafe { &mut *this }.0.fill_buf()))) + } + + fn consume(mut self: Pin<&mut Self>, amt: usize) { + self.0.consume(amt) + } +} diff --git a/third_party/rust/futures-util/src/io/buf_reader.rs b/third_party/rust/futures-util/src/io/buf_reader.rs new file mode 100644 index 0000000000..0334a9f081 --- /dev/null +++ b/third_party/rust/futures-util/src/io/buf_reader.rs @@ -0,0 +1,263 @@ +use super::DEFAULT_BUF_SIZE; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, IoSliceMut, SeekFrom}; +use pin_project_lite::pin_project; +use std::io::{self, Read}; +use std::pin::Pin; +use std::{cmp, fmt}; + +pin_project! { + /// The `BufReader` struct adds buffering to any reader. + /// + /// It can be excessively inefficient to work directly with a [`AsyncRead`] + /// instance. A `BufReader` performs large, infrequent reads on the underlying + /// [`AsyncRead`] and maintains an in-memory buffer of the results. + /// + /// `BufReader` can improve the speed of programs that make *small* and + /// *repeated* read calls to the same file or network socket. It does not + /// help when reading very large amounts at once, or reading just one or a few + /// times. It also provides no advantage when reading from a source that is + /// already in memory, like a `Vec<u8>`. + /// + /// When the `BufReader` is dropped, the contents of its buffer will be + /// discarded. Creating multiple instances of a `BufReader` on the same + /// stream can cause data loss. + /// + /// [`AsyncRead`]: futures_io::AsyncRead + /// + // TODO: Examples + pub struct BufReader<R> { + #[pin] + inner: R, + buffer: Box<[u8]>, + pos: usize, + cap: usize, + } +} + +impl<R: AsyncRead> BufReader<R> { + /// Creates a new `BufReader` with a default buffer capacity. The default is currently 8 KB, + /// but may change in the future. + pub fn new(inner: R) -> Self { + Self::with_capacity(DEFAULT_BUF_SIZE, inner) + } + + /// Creates a new `BufReader` with the specified buffer capacity. + pub fn with_capacity(capacity: usize, inner: R) -> Self { + unsafe { + let mut buffer = Vec::with_capacity(capacity); + buffer.set_len(capacity); + super::initialize(&inner, &mut buffer); + Self { inner, buffer: buffer.into_boxed_slice(), pos: 0, cap: 0 } + } + } + + delegate_access_inner!(inner, R, ()); + + /// Returns a reference to the internally buffered data. + /// + /// Unlike `fill_buf`, this will not attempt to fill the buffer if it is empty. + pub fn buffer(&self) -> &[u8] { + &self.buffer[self.pos..self.cap] + } + + /// Invalidates all data in the internal buffer. + #[inline] + fn discard_buffer(self: Pin<&mut Self>) { + let this = self.project(); + *this.pos = 0; + *this.cap = 0; + } +} + +impl<R: AsyncRead + AsyncSeek> BufReader<R> { + /// Seeks relative to the current position. If the new position lies within the buffer, + /// the buffer will not be flushed, allowing for more efficient seeks. + /// This method does not return the location of the underlying reader, so the caller + /// must track this information themselves if it is required. + pub fn seek_relative(self: Pin<&mut Self>, offset: i64) -> SeeKRelative<'_, R> { + SeeKRelative { inner: self, offset, first: true } + } + + /// Attempts to seek relative to the current position. If the new position lies within the buffer, + /// the buffer will not be flushed, allowing for more efficient seeks. + /// This method does not return the location of the underlying reader, so the caller + /// must track this information themselves if it is required. + pub fn poll_seek_relative( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + offset: i64, + ) -> Poll<io::Result<()>> { + let pos = self.pos as u64; + if offset < 0 { + if let Some(new_pos) = pos.checked_sub((-offset) as u64) { + *self.project().pos = new_pos as usize; + return Poll::Ready(Ok(())); + } + } else if let Some(new_pos) = pos.checked_add(offset as u64) { + if new_pos <= self.cap as u64 { + *self.project().pos = new_pos as usize; + return Poll::Ready(Ok(())); + } + } + self.poll_seek(cx, SeekFrom::Current(offset)).map(|res| res.map(|_| ())) + } +} + +impl<R: AsyncRead> AsyncRead for BufReader<R> { + fn poll_read( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &mut [u8], + ) -> Poll<io::Result<usize>> { + // If we don't have any buffered data and we're doing a massive read + // (larger than our internal buffer), bypass our internal buffer + // entirely. + if self.pos == self.cap && buf.len() >= self.buffer.len() { + let res = ready!(self.as_mut().project().inner.poll_read(cx, buf)); + self.discard_buffer(); + return Poll::Ready(res); + } + let mut rem = ready!(self.as_mut().poll_fill_buf(cx))?; + let nread = rem.read(buf)?; + self.consume(nread); + Poll::Ready(Ok(nread)) + } + + fn poll_read_vectored( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &mut [IoSliceMut<'_>], + ) -> Poll<io::Result<usize>> { + let total_len = bufs.iter().map(|b| b.len()).sum::<usize>(); + if self.pos == self.cap && total_len >= self.buffer.len() { + let res = ready!(self.as_mut().project().inner.poll_read_vectored(cx, bufs)); + self.discard_buffer(); + return Poll::Ready(res); + } + let mut rem = ready!(self.as_mut().poll_fill_buf(cx))?; + let nread = rem.read_vectored(bufs)?; + self.consume(nread); + Poll::Ready(Ok(nread)) + } +} + +impl<R: AsyncRead> AsyncBufRead for BufReader<R> { + fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> { + let this = self.project(); + + // If we've reached the end of our internal buffer then we need to fetch + // some more data from the underlying reader. + // Branch using `>=` instead of the more correct `==` + // to tell the compiler that the pos..cap slice is always valid. + if *this.pos >= *this.cap { + debug_assert!(*this.pos == *this.cap); + *this.cap = ready!(this.inner.poll_read(cx, this.buffer))?; + *this.pos = 0; + } + Poll::Ready(Ok(&this.buffer[*this.pos..*this.cap])) + } + + fn consume(self: Pin<&mut Self>, amt: usize) { + *self.project().pos = cmp::min(self.pos + amt, self.cap); + } +} + +impl<R: AsyncWrite> AsyncWrite for BufReader<R> { + delegate_async_write!(inner); +} + +impl<R: fmt::Debug> fmt::Debug for BufReader<R> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("BufReader") + .field("reader", &self.inner) + .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buffer.len())) + .finish() + } +} + +impl<R: AsyncRead + AsyncSeek> AsyncSeek for BufReader<R> { + /// Seek to an offset, in bytes, in the underlying reader. + /// + /// The position used for seeking with `SeekFrom::Current(_)` is the + /// position the underlying reader would be at if the `BufReader` had no + /// internal buffer. + /// + /// Seeking always discards the internal buffer, even if the seek position + /// would otherwise fall within it. This guarantees that calling + /// `.into_inner()` immediately after a seek yields the underlying reader + /// at the same position. + /// + /// To seek without discarding the internal buffer, use + /// [`BufReader::seek_relative`](BufReader::seek_relative) or + /// [`BufReader::poll_seek_relative`](BufReader::poll_seek_relative). + /// + /// See [`AsyncSeek`](futures_io::AsyncSeek) for more details. + /// + /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)` + /// where `n` minus the internal buffer length overflows an `i64`, two + /// seeks will be performed instead of one. If the second seek returns + /// `Err`, the underlying reader will be left at the same position it would + /// have if you called `seek` with `SeekFrom::Current(0)`. + fn poll_seek( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + pos: SeekFrom, + ) -> Poll<io::Result<u64>> { + let result: u64; + if let SeekFrom::Current(n) = pos { + let remainder = (self.cap - self.pos) as i64; + // it should be safe to assume that remainder fits within an i64 as the alternative + // means we managed to allocate 8 exbibytes and that's absurd. + // But it's not out of the realm of possibility for some weird underlying reader to + // support seeking by i64::min_value() so we need to handle underflow when subtracting + // remainder. + if let Some(offset) = n.checked_sub(remainder) { + result = + ready!(self.as_mut().project().inner.poll_seek(cx, SeekFrom::Current(offset)))?; + } else { + // seek backwards by our remainder, and then by the offset + ready!(self.as_mut().project().inner.poll_seek(cx, SeekFrom::Current(-remainder)))?; + self.as_mut().discard_buffer(); + result = ready!(self.as_mut().project().inner.poll_seek(cx, SeekFrom::Current(n)))?; + } + } else { + // Seeking with Start/End doesn't care about our buffer length. + result = ready!(self.as_mut().project().inner.poll_seek(cx, pos))?; + } + self.discard_buffer(); + Poll::Ready(Ok(result)) + } +} + +/// Future for the [`BufReader::seek_relative`](self::BufReader::seek_relative) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless polled"] +pub struct SeeKRelative<'a, R> { + inner: Pin<&'a mut BufReader<R>>, + offset: i64, + first: bool, +} + +impl<R> Future for SeeKRelative<'_, R> +where + R: AsyncRead + AsyncSeek, +{ + type Output = io::Result<()>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let offset = self.offset; + if self.first { + self.first = false; + self.inner.as_mut().poll_seek_relative(cx, offset) + } else { + self.inner + .as_mut() + .as_mut() + .poll_seek(cx, SeekFrom::Current(offset)) + .map(|res| res.map(|_| ())) + } + } +} diff --git a/third_party/rust/futures-util/src/io/buf_writer.rs b/third_party/rust/futures-util/src/io/buf_writer.rs new file mode 100644 index 0000000000..cb74863ad0 --- /dev/null +++ b/third_party/rust/futures-util/src/io/buf_writer.rs @@ -0,0 +1,224 @@ +use super::DEFAULT_BUF_SIZE; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, IoSlice, SeekFrom}; +use pin_project_lite::pin_project; +use std::fmt; +use std::io::{self, Write}; +use std::pin::Pin; +use std::ptr; + +pin_project! { + /// Wraps a writer and buffers its output. + /// + /// It can be excessively inefficient to work directly with something that + /// implements [`AsyncWrite`]. A `BufWriter` keeps an in-memory buffer of data and + /// writes it to an underlying writer in large, infrequent batches. + /// + /// `BufWriter` can improve the speed of programs that make *small* and + /// *repeated* write calls to the same file or network socket. It does not + /// help when writing very large amounts at once, or writing just one or a few + /// times. It also provides no advantage when writing to a destination that is + /// in memory, like a `Vec<u8>`. + /// + /// When the `BufWriter` is dropped, the contents of its buffer will be + /// discarded. Creating multiple instances of a `BufWriter` on the same + /// stream can cause data loss. If you need to write out the contents of its + /// buffer, you must manually call flush before the writer is dropped. + /// + /// [`AsyncWrite`]: futures_io::AsyncWrite + /// [`flush`]: super::AsyncWriteExt::flush + /// + // TODO: Examples + pub struct BufWriter<W> { + #[pin] + inner: W, + buf: Vec<u8>, + written: usize, + } +} + +impl<W: AsyncWrite> BufWriter<W> { + /// Creates a new `BufWriter` with a default buffer capacity. The default is currently 8 KB, + /// but may change in the future. + pub fn new(inner: W) -> Self { + Self::with_capacity(DEFAULT_BUF_SIZE, inner) + } + + /// Creates a new `BufWriter` with the specified buffer capacity. + pub fn with_capacity(cap: usize, inner: W) -> Self { + Self { inner, buf: Vec::with_capacity(cap), written: 0 } + } + + pub(super) fn flush_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + let mut this = self.project(); + + let len = this.buf.len(); + let mut ret = Ok(()); + while *this.written < len { + match ready!(this.inner.as_mut().poll_write(cx, &this.buf[*this.written..])) { + Ok(0) => { + ret = Err(io::Error::new( + io::ErrorKind::WriteZero, + "failed to write the buffered data", + )); + break; + } + Ok(n) => *this.written += n, + Err(e) => { + ret = Err(e); + break; + } + } + } + if *this.written > 0 { + this.buf.drain(..*this.written); + } + *this.written = 0; + Poll::Ready(ret) + } + + delegate_access_inner!(inner, W, ()); + + /// Returns a reference to the internally buffered data. + pub fn buffer(&self) -> &[u8] { + &self.buf + } + + /// Capacity of `buf`. how many chars can be held in buffer + pub(super) fn capacity(&self) -> usize { + self.buf.capacity() + } + + /// Remaining number of bytes to reach `buf` 's capacity + #[inline] + pub(super) fn spare_capacity(&self) -> usize { + self.buf.capacity() - self.buf.len() + } + + /// Write a byte slice directly into buffer + /// + /// Will truncate the number of bytes written to `spare_capacity()` so you want to + /// calculate the size of your slice to avoid losing bytes + /// + /// Based on `std::io::BufWriter` + pub(super) fn write_to_buf(self: Pin<&mut Self>, buf: &[u8]) -> usize { + let available = self.spare_capacity(); + let amt_to_buffer = available.min(buf.len()); + + // SAFETY: `amt_to_buffer` is <= buffer's spare capacity by construction. + unsafe { + self.write_to_buffer_unchecked(&buf[..amt_to_buffer]); + } + + amt_to_buffer + } + + /// Write byte slice directly into `self.buf` + /// + /// Based on `std::io::BufWriter` + #[inline] + unsafe fn write_to_buffer_unchecked(self: Pin<&mut Self>, buf: &[u8]) { + debug_assert!(buf.len() <= self.spare_capacity()); + let this = self.project(); + let old_len = this.buf.len(); + let buf_len = buf.len(); + let src = buf.as_ptr(); + let dst = this.buf.as_mut_ptr().add(old_len); + ptr::copy_nonoverlapping(src, dst, buf_len); + this.buf.set_len(old_len + buf_len); + } + + /// Write directly using `inner`, bypassing buffering + pub(super) fn inner_poll_write( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &[u8], + ) -> Poll<io::Result<usize>> { + self.project().inner.poll_write(cx, buf) + } + + /// Write directly using `inner`, bypassing buffering + pub(super) fn inner_poll_write_vectored( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<io::Result<usize>> { + self.project().inner.poll_write_vectored(cx, bufs) + } +} + +impl<W: AsyncWrite> AsyncWrite for BufWriter<W> { + fn poll_write( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &[u8], + ) -> Poll<io::Result<usize>> { + if self.buf.len() + buf.len() > self.buf.capacity() { + ready!(self.as_mut().flush_buf(cx))?; + } + if buf.len() >= self.buf.capacity() { + self.project().inner.poll_write(cx, buf) + } else { + Poll::Ready(self.project().buf.write(buf)) + } + } + + fn poll_write_vectored( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<io::Result<usize>> { + let total_len = bufs.iter().map(|b| b.len()).sum::<usize>(); + if self.buf.len() + total_len > self.buf.capacity() { + ready!(self.as_mut().flush_buf(cx))?; + } + if total_len >= self.buf.capacity() { + self.project().inner.poll_write_vectored(cx, bufs) + } else { + Poll::Ready(self.project().buf.write_vectored(bufs)) + } + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + ready!(self.as_mut().flush_buf(cx))?; + self.project().inner.poll_flush(cx) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + ready!(self.as_mut().flush_buf(cx))?; + self.project().inner.poll_close(cx) + } +} + +impl<W: AsyncRead> AsyncRead for BufWriter<W> { + delegate_async_read!(inner); +} + +impl<W: AsyncBufRead> AsyncBufRead for BufWriter<W> { + delegate_async_buf_read!(inner); +} + +impl<W: fmt::Debug> fmt::Debug for BufWriter<W> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("BufWriter") + .field("writer", &self.inner) + .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity())) + .field("written", &self.written) + .finish() + } +} + +impl<W: AsyncWrite + AsyncSeek> AsyncSeek for BufWriter<W> { + /// Seek to the offset, in bytes, in the underlying writer. + /// + /// Seeking always writes out the internal buffer before seeking. + fn poll_seek( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + pos: SeekFrom, + ) -> Poll<io::Result<u64>> { + ready!(self.as_mut().flush_buf(cx))?; + self.project().inner.poll_seek(cx, pos) + } +} diff --git a/third_party/rust/futures-util/src/io/chain.rs b/third_party/rust/futures-util/src/io/chain.rs new file mode 100644 index 0000000000..728a3d2dc0 --- /dev/null +++ b/third_party/rust/futures-util/src/io/chain.rs @@ -0,0 +1,142 @@ +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncBufRead, AsyncRead, IoSliceMut}; +use pin_project_lite::pin_project; +use std::fmt; +use std::io; +use std::pin::Pin; + +pin_project! { + /// Reader for the [`chain`](super::AsyncReadExt::chain) method. + #[must_use = "readers do nothing unless polled"] + pub struct Chain<T, U> { + #[pin] + first: T, + #[pin] + second: U, + done_first: bool, + } +} + +impl<T, U> Chain<T, U> +where + T: AsyncRead, + U: AsyncRead, +{ + pub(super) fn new(first: T, second: U) -> Self { + Self { first, second, done_first: false } + } + + /// Gets references to the underlying readers in this `Chain`. + pub fn get_ref(&self) -> (&T, &U) { + (&self.first, &self.second) + } + + /// Gets mutable references to the underlying readers in this `Chain`. + /// + /// Care should be taken to avoid modifying the internal I/O state of the + /// underlying readers as doing so may corrupt the internal state of this + /// `Chain`. + pub fn get_mut(&mut self) -> (&mut T, &mut U) { + (&mut self.first, &mut self.second) + } + + /// Gets pinned mutable references to the underlying readers in this `Chain`. + /// + /// Care should be taken to avoid modifying the internal I/O state of the + /// underlying readers as doing so may corrupt the internal state of this + /// `Chain`. + pub fn get_pin_mut(self: Pin<&mut Self>) -> (Pin<&mut T>, Pin<&mut U>) { + let this = self.project(); + (this.first, this.second) + } + + /// Consumes the `Chain`, returning the wrapped readers. + pub fn into_inner(self) -> (T, U) { + (self.first, self.second) + } +} + +impl<T, U> fmt::Debug for Chain<T, U> +where + T: fmt::Debug, + U: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Chain") + .field("t", &self.first) + .field("u", &self.second) + .field("done_first", &self.done_first) + .finish() + } +} + +impl<T, U> AsyncRead for Chain<T, U> +where + T: AsyncRead, + U: AsyncRead, +{ + fn poll_read( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &mut [u8], + ) -> Poll<io::Result<usize>> { + let this = self.project(); + + if !*this.done_first { + match ready!(this.first.poll_read(cx, buf)?) { + 0 if !buf.is_empty() => *this.done_first = true, + n => return Poll::Ready(Ok(n)), + } + } + this.second.poll_read(cx, buf) + } + + fn poll_read_vectored( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &mut [IoSliceMut<'_>], + ) -> Poll<io::Result<usize>> { + let this = self.project(); + + if !*this.done_first { + let n = ready!(this.first.poll_read_vectored(cx, bufs)?); + if n == 0 && bufs.iter().any(|b| !b.is_empty()) { + *this.done_first = true + } else { + return Poll::Ready(Ok(n)); + } + } + this.second.poll_read_vectored(cx, bufs) + } +} + +impl<T, U> AsyncBufRead for Chain<T, U> +where + T: AsyncBufRead, + U: AsyncBufRead, +{ + fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> { + let this = self.project(); + + if !*this.done_first { + match ready!(this.first.poll_fill_buf(cx)?) { + buf if buf.is_empty() => { + *this.done_first = true; + } + buf => return Poll::Ready(Ok(buf)), + } + } + this.second.poll_fill_buf(cx) + } + + fn consume(self: Pin<&mut Self>, amt: usize) { + let this = self.project(); + + if !*this.done_first { + this.first.consume(amt) + } else { + this.second.consume(amt) + } + } +} diff --git a/third_party/rust/futures-util/src/io/close.rs b/third_party/rust/futures-util/src/io/close.rs new file mode 100644 index 0000000000..b94459279a --- /dev/null +++ b/third_party/rust/futures-util/src/io/close.rs @@ -0,0 +1,28 @@ +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncWrite; +use std::io; +use std::pin::Pin; + +/// Future for the [`close`](super::AsyncWriteExt::close) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Close<'a, W: ?Sized> { + writer: &'a mut W, +} + +impl<W: ?Sized + Unpin> Unpin for Close<'_, W> {} + +impl<'a, W: AsyncWrite + ?Sized + Unpin> Close<'a, W> { + pub(super) fn new(writer: &'a mut W) -> Self { + Self { writer } + } +} + +impl<W: AsyncWrite + ?Sized + Unpin> Future for Close<'_, W> { + type Output = io::Result<()>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + Pin::new(&mut *self.writer).poll_close(cx) + } +} diff --git a/third_party/rust/futures-util/src/io/copy.rs b/third_party/rust/futures-util/src/io/copy.rs new file mode 100644 index 0000000000..c80add271b --- /dev/null +++ b/third_party/rust/futures-util/src/io/copy.rs @@ -0,0 +1,58 @@ +use super::{copy_buf, BufReader, CopyBuf}; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncRead, AsyncWrite}; +use pin_project_lite::pin_project; +use std::io; +use std::pin::Pin; + +/// Creates a future which copies all the bytes from one object to another. +/// +/// The returned future will copy all the bytes read from this `AsyncRead` into the +/// `writer` specified. This future will only complete once the `reader` has hit +/// EOF and all bytes have been written to and flushed from the `writer` +/// provided. +/// +/// On success the number of bytes is returned. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::io::{self, AsyncWriteExt, Cursor}; +/// +/// let reader = Cursor::new([1, 2, 3, 4]); +/// let mut writer = Cursor::new(vec![0u8; 5]); +/// +/// let bytes = io::copy(reader, &mut writer).await?; +/// writer.close().await?; +/// +/// assert_eq!(bytes, 4); +/// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]); +/// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); +/// ``` +pub fn copy<R, W>(reader: R, writer: &mut W) -> Copy<'_, R, W> +where + R: AsyncRead, + W: AsyncWrite + Unpin + ?Sized, +{ + Copy { inner: copy_buf(BufReader::new(reader), writer) } +} + +pin_project! { + /// Future for the [`copy()`] function. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Copy<'a, R, W: ?Sized> { + #[pin] + inner: CopyBuf<'a, BufReader<R>, W>, + } +} + +impl<R: AsyncRead, W: AsyncWrite + Unpin + ?Sized> Future for Copy<'_, R, W> { + type Output = io::Result<u64>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + self.project().inner.poll(cx) + } +} diff --git a/third_party/rust/futures-util/src/io/copy_buf.rs b/third_party/rust/futures-util/src/io/copy_buf.rs new file mode 100644 index 0000000000..50f7abdca9 --- /dev/null +++ b/third_party/rust/futures-util/src/io/copy_buf.rs @@ -0,0 +1,78 @@ +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncBufRead, AsyncWrite}; +use pin_project_lite::pin_project; +use std::io; +use std::pin::Pin; + +/// Creates a future which copies all the bytes from one object to another. +/// +/// The returned future will copy all the bytes read from this `AsyncBufRead` into the +/// `writer` specified. This future will only complete once the `reader` has hit +/// EOF and all bytes have been written to and flushed from the `writer` +/// provided. +/// +/// On success the number of bytes is returned. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::io::{self, AsyncWriteExt, Cursor}; +/// +/// let reader = Cursor::new([1, 2, 3, 4]); +/// let mut writer = Cursor::new(vec![0u8; 5]); +/// +/// let bytes = io::copy_buf(reader, &mut writer).await?; +/// writer.close().await?; +/// +/// assert_eq!(bytes, 4); +/// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]); +/// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); +/// ``` +pub fn copy_buf<R, W>(reader: R, writer: &mut W) -> CopyBuf<'_, R, W> +where + R: AsyncBufRead, + W: AsyncWrite + Unpin + ?Sized, +{ + CopyBuf { reader, writer, amt: 0 } +} + +pin_project! { + /// Future for the [`copy_buf()`] function. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct CopyBuf<'a, R, W: ?Sized> { + #[pin] + reader: R, + writer: &'a mut W, + amt: u64, + } +} + +impl<R, W> Future for CopyBuf<'_, R, W> +where + R: AsyncBufRead, + W: AsyncWrite + Unpin + ?Sized, +{ + type Output = io::Result<u64>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut this = self.project(); + loop { + let buffer = ready!(this.reader.as_mut().poll_fill_buf(cx))?; + if buffer.is_empty() { + ready!(Pin::new(&mut this.writer).poll_flush(cx))?; + return Poll::Ready(Ok(*this.amt)); + } + + let i = ready!(Pin::new(&mut this.writer).poll_write(cx, buffer))?; + if i == 0 { + return Poll::Ready(Err(io::ErrorKind::WriteZero.into())); + } + *this.amt += i as u64; + this.reader.as_mut().consume(i); + } + } +} diff --git a/third_party/rust/futures-util/src/io/copy_buf_abortable.rs b/third_party/rust/futures-util/src/io/copy_buf_abortable.rs new file mode 100644 index 0000000000..fdbc4a5f00 --- /dev/null +++ b/third_party/rust/futures-util/src/io/copy_buf_abortable.rs @@ -0,0 +1,124 @@ +use crate::abortable::{AbortHandle, AbortInner, Aborted}; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncBufRead, AsyncWrite}; +use pin_project_lite::pin_project; +use std::io; +use std::pin::Pin; +use std::sync::atomic::Ordering; +use std::sync::Arc; + +/// Creates a future which copies all the bytes from one object to another, with its `AbortHandle`. +/// +/// The returned future will copy all the bytes read from this `AsyncBufRead` into the +/// `writer` specified. This future will only complete once abort has been requested or the `reader` has hit +/// EOF and all bytes have been written to and flushed from the `writer` +/// provided. +/// +/// On success the number of bytes is returned. If aborted, `Aborted` is returned. Otherwise, the underlying error is returned. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::io::{self, AsyncWriteExt, Cursor}; +/// use futures::future::Aborted; +/// +/// let reader = Cursor::new([1, 2, 3, 4]); +/// let mut writer = Cursor::new(vec![0u8; 5]); +/// +/// let (fut, abort_handle) = io::copy_buf_abortable(reader, &mut writer); +/// let bytes = fut.await; +/// abort_handle.abort(); +/// writer.close().await.unwrap(); +/// match bytes { +/// Ok(Ok(n)) => { +/// assert_eq!(n, 4); +/// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]); +/// Ok(n) +/// }, +/// Ok(Err(a)) => { +/// Err::<u64, Aborted>(a) +/// } +/// Err(e) => panic!("{}", e) +/// } +/// # }).unwrap(); +/// ``` +pub fn copy_buf_abortable<R, W>( + reader: R, + writer: &mut W, +) -> (CopyBufAbortable<'_, R, W>, AbortHandle) +where + R: AsyncBufRead, + W: AsyncWrite + Unpin + ?Sized, +{ + let (handle, reg) = AbortHandle::new_pair(); + (CopyBufAbortable { reader, writer, amt: 0, inner: reg.inner }, handle) +} + +pin_project! { + /// Future for the [`copy_buf()`] function. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct CopyBufAbortable<'a, R, W: ?Sized> { + #[pin] + reader: R, + writer: &'a mut W, + amt: u64, + inner: Arc<AbortInner> + } +} + +macro_rules! ready_or_break { + ($e:expr $(,)?) => { + match $e { + $crate::task::Poll::Ready(t) => t, + $crate::task::Poll::Pending => break, + } + }; +} + +impl<R, W> Future for CopyBufAbortable<'_, R, W> +where + R: AsyncBufRead, + W: AsyncWrite + Unpin + Sized, +{ + type Output = Result<Result<u64, Aborted>, io::Error>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut this = self.project(); + loop { + // Check if the task has been aborted + if this.inner.aborted.load(Ordering::Relaxed) { + return Poll::Ready(Ok(Err(Aborted))); + } + + // Read some bytes from the reader, and if we have reached EOF, return total bytes read + let buffer = ready_or_break!(this.reader.as_mut().poll_fill_buf(cx))?; + if buffer.is_empty() { + ready_or_break!(Pin::new(&mut this.writer).poll_flush(cx))?; + return Poll::Ready(Ok(Ok(*this.amt))); + } + + // Pass the buffer to the writer, and update the amount written + let i = ready_or_break!(Pin::new(&mut this.writer).poll_write(cx, buffer))?; + if i == 0 { + return Poll::Ready(Err(io::ErrorKind::WriteZero.into())); + } + *this.amt += i as u64; + this.reader.as_mut().consume(i); + } + // Schedule the task to be woken up again. + // Never called unless Poll::Pending is returned from io objects. + this.inner.waker.register(cx.waker()); + + // Check to see if the task was aborted between the first check and + // registration. + // Checking with `Relaxed` is sufficient because + // `register` introduces an `AcqRel` barrier. + if this.inner.aborted.load(Ordering::Relaxed) { + return Poll::Ready(Ok(Err(Aborted))); + } + Poll::Pending + } +} diff --git a/third_party/rust/futures-util/src/io/cursor.rs b/third_party/rust/futures-util/src/io/cursor.rs new file mode 100644 index 0000000000..b6fb3724c7 --- /dev/null +++ b/third_party/rust/futures-util/src/io/cursor.rs @@ -0,0 +1,240 @@ +use futures_core::task::{Context, Poll}; +#[cfg(feature = "read_initializer")] +use futures_io::Initializer; +use futures_io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, IoSlice, IoSliceMut, SeekFrom}; +use std::io; +use std::pin::Pin; + +/// A `Cursor` wraps an in-memory buffer and provides it with a +/// [`AsyncSeek`] implementation. +/// +/// `Cursor`s are used with in-memory buffers, anything implementing +/// `AsRef<[u8]>`, to allow them to implement [`AsyncRead`] and/or [`AsyncWrite`], +/// allowing these buffers to be used anywhere you might use a reader or writer +/// that does actual I/O. +/// +/// This library implements some I/O traits on various types which +/// are commonly used as a buffer, like `Cursor<`[`Vec`]`<u8>>` and +/// `Cursor<`[`&[u8]`][bytes]`>`. +/// +/// [`AsyncSeek`]: trait.AsyncSeek.html +/// [`AsyncRead`]: trait.AsyncRead.html +/// [`AsyncWrite`]: trait.AsyncWrite.html +/// [bytes]: https://doc.rust-lang.org/std/primitive.slice.html +#[derive(Clone, Debug, Default)] +pub struct Cursor<T> { + inner: io::Cursor<T>, +} + +impl<T> Cursor<T> { + /// Creates a new cursor wrapping the provided underlying in-memory buffer. + /// + /// Cursor initial position is `0` even if underlying buffer (e.g., `Vec`) + /// is not empty. So writing to cursor starts with overwriting `Vec` + /// content, not with appending to it. + /// + /// # Examples + /// + /// ``` + /// use futures::io::Cursor; + /// + /// let buff = Cursor::new(Vec::new()); + /// # fn force_inference(_: &Cursor<Vec<u8>>) {} + /// # force_inference(&buff); + /// ``` + pub fn new(inner: T) -> Self { + Self { inner: io::Cursor::new(inner) } + } + + /// Consumes this cursor, returning the underlying value. + /// + /// # Examples + /// + /// ``` + /// use futures::io::Cursor; + /// + /// let buff = Cursor::new(Vec::new()); + /// # fn force_inference(_: &Cursor<Vec<u8>>) {} + /// # force_inference(&buff); + /// + /// let vec = buff.into_inner(); + /// ``` + pub fn into_inner(self) -> T { + self.inner.into_inner() + } + + /// Gets a reference to the underlying value in this cursor. + /// + /// # Examples + /// + /// ``` + /// use futures::io::Cursor; + /// + /// let buff = Cursor::new(Vec::new()); + /// # fn force_inference(_: &Cursor<Vec<u8>>) {} + /// # force_inference(&buff); + /// + /// let reference = buff.get_ref(); + /// ``` + pub fn get_ref(&self) -> &T { + self.inner.get_ref() + } + + /// Gets a mutable reference to the underlying value in this cursor. + /// + /// Care should be taken to avoid modifying the internal I/O state of the + /// underlying value as it may corrupt this cursor's position. + /// + /// # Examples + /// + /// ``` + /// use futures::io::Cursor; + /// + /// let mut buff = Cursor::new(Vec::new()); + /// # fn force_inference(_: &Cursor<Vec<u8>>) {} + /// # force_inference(&buff); + /// + /// let reference = buff.get_mut(); + /// ``` + pub fn get_mut(&mut self) -> &mut T { + self.inner.get_mut() + } + + /// Returns the current position of this cursor. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncSeekExt, Cursor, SeekFrom}; + /// + /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]); + /// + /// assert_eq!(buff.position(), 0); + /// + /// buff.seek(SeekFrom::Current(2)).await?; + /// assert_eq!(buff.position(), 2); + /// + /// buff.seek(SeekFrom::Current(-1)).await?; + /// assert_eq!(buff.position(), 1); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + pub fn position(&self) -> u64 { + self.inner.position() + } + + /// Sets the position of this cursor. + /// + /// # Examples + /// + /// ``` + /// use futures::io::Cursor; + /// + /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]); + /// + /// assert_eq!(buff.position(), 0); + /// + /// buff.set_position(2); + /// assert_eq!(buff.position(), 2); + /// + /// buff.set_position(4); + /// assert_eq!(buff.position(), 4); + /// ``` + pub fn set_position(&mut self, pos: u64) { + self.inner.set_position(pos) + } +} + +impl<T> AsyncSeek for Cursor<T> +where + T: AsRef<[u8]> + Unpin, +{ + fn poll_seek( + mut self: Pin<&mut Self>, + _: &mut Context<'_>, + pos: SeekFrom, + ) -> Poll<io::Result<u64>> { + Poll::Ready(io::Seek::seek(&mut self.inner, pos)) + } +} + +impl<T: AsRef<[u8]> + Unpin> AsyncRead for Cursor<T> { + #[cfg(feature = "read_initializer")] + #[inline] + unsafe fn initializer(&self) -> Initializer { + io::Read::initializer(&self.inner) + } + + fn poll_read( + mut self: Pin<&mut Self>, + _cx: &mut Context<'_>, + buf: &mut [u8], + ) -> Poll<io::Result<usize>> { + Poll::Ready(io::Read::read(&mut self.inner, buf)) + } + + fn poll_read_vectored( + mut self: Pin<&mut Self>, + _: &mut Context<'_>, + bufs: &mut [IoSliceMut<'_>], + ) -> Poll<io::Result<usize>> { + Poll::Ready(io::Read::read_vectored(&mut self.inner, bufs)) + } +} + +impl<T> AsyncBufRead for Cursor<T> +where + T: AsRef<[u8]> + Unpin, +{ + fn poll_fill_buf(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<&[u8]>> { + Poll::Ready(io::BufRead::fill_buf(&mut self.get_mut().inner)) + } + + fn consume(mut self: Pin<&mut Self>, amt: usize) { + io::BufRead::consume(&mut self.inner, amt) + } +} + +macro_rules! delegate_async_write_to_stdio { + () => { + fn poll_write( + mut self: Pin<&mut Self>, + _: &mut Context<'_>, + buf: &[u8], + ) -> Poll<io::Result<usize>> { + Poll::Ready(io::Write::write(&mut self.inner, buf)) + } + + fn poll_write_vectored( + mut self: Pin<&mut Self>, + _: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<io::Result<usize>> { + Poll::Ready(io::Write::write_vectored(&mut self.inner, bufs)) + } + + fn poll_flush(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> { + Poll::Ready(io::Write::flush(&mut self.inner)) + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + self.poll_flush(cx) + } + }; +} + +impl AsyncWrite for Cursor<&mut [u8]> { + delegate_async_write_to_stdio!(); +} + +impl AsyncWrite for Cursor<&mut Vec<u8>> { + delegate_async_write_to_stdio!(); +} + +impl AsyncWrite for Cursor<Vec<u8>> { + delegate_async_write_to_stdio!(); +} + +impl AsyncWrite for Cursor<Box<[u8]>> { + delegate_async_write_to_stdio!(); +} diff --git a/third_party/rust/futures-util/src/io/empty.rs b/third_party/rust/futures-util/src/io/empty.rs new file mode 100644 index 0000000000..02f6103f54 --- /dev/null +++ b/third_party/rust/futures-util/src/io/empty.rs @@ -0,0 +1,59 @@ +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncBufRead, AsyncRead}; +use std::fmt; +use std::io; +use std::pin::Pin; + +/// Reader for the [`empty()`] function. +#[must_use = "readers do nothing unless polled"] +pub struct Empty { + _priv: (), +} + +/// Constructs a new handle to an empty reader. +/// +/// All reads from the returned reader will return `Poll::Ready(Ok(0))`. +/// +/// # Examples +/// +/// A slightly sad example of not reading anything into a buffer: +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::io::{self, AsyncReadExt}; +/// +/// let mut buffer = String::new(); +/// let mut reader = io::empty(); +/// reader.read_to_string(&mut buffer).await?; +/// assert!(buffer.is_empty()); +/// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); +/// ``` +pub fn empty() -> Empty { + Empty { _priv: () } +} + +impl AsyncRead for Empty { + #[inline] + fn poll_read( + self: Pin<&mut Self>, + _: &mut Context<'_>, + _: &mut [u8], + ) -> Poll<io::Result<usize>> { + Poll::Ready(Ok(0)) + } +} + +impl AsyncBufRead for Empty { + #[inline] + fn poll_fill_buf(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<&[u8]>> { + Poll::Ready(Ok(&[])) + } + #[inline] + fn consume(self: Pin<&mut Self>, _: usize) {} +} + +impl fmt::Debug for Empty { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.pad("Empty { .. }") + } +} diff --git a/third_party/rust/futures-util/src/io/fill_buf.rs b/third_party/rust/futures-util/src/io/fill_buf.rs new file mode 100644 index 0000000000..a1484c0322 --- /dev/null +++ b/third_party/rust/futures-util/src/io/fill_buf.rs @@ -0,0 +1,51 @@ +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncBufRead; +use std::io; +use std::pin::Pin; + +/// Future for the [`fill_buf`](super::AsyncBufReadExt::fill_buf) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct FillBuf<'a, R: ?Sized> { + reader: Option<&'a mut R>, +} + +impl<R: ?Sized> Unpin for FillBuf<'_, R> {} + +impl<'a, R: AsyncBufRead + ?Sized + Unpin> FillBuf<'a, R> { + pub(super) fn new(reader: &'a mut R) -> Self { + Self { reader: Some(reader) } + } +} + +impl<'a, R> Future for FillBuf<'a, R> +where + R: AsyncBufRead + ?Sized + Unpin, +{ + type Output = io::Result<&'a [u8]>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + let reader = this.reader.take().expect("Polled FillBuf after completion"); + + match Pin::new(&mut *reader).poll_fill_buf(cx) { + // With polonius it is possible to remove this inner match and just have the correct + // lifetime of the reference inferred based on which branch is taken + Poll::Ready(Ok(_)) => match Pin::new(reader).poll_fill_buf(cx) { + Poll::Ready(Ok(slice)) => Poll::Ready(Ok(slice)), + Poll::Ready(Err(err)) => { + unreachable!("reader indicated readiness but then returned an error: {:?}", err) + } + Poll::Pending => { + unreachable!("reader indicated readiness but then returned pending") + } + }, + Poll::Ready(Err(err)) => Poll::Ready(Err(err)), + Poll::Pending => { + this.reader = Some(reader); + Poll::Pending + } + } + } +} diff --git a/third_party/rust/futures-util/src/io/flush.rs b/third_party/rust/futures-util/src/io/flush.rs new file mode 100644 index 0000000000..b75d14c5d3 --- /dev/null +++ b/third_party/rust/futures-util/src/io/flush.rs @@ -0,0 +1,31 @@ +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncWrite; +use std::io; +use std::pin::Pin; + +/// Future for the [`flush`](super::AsyncWriteExt::flush) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Flush<'a, W: ?Sized> { + writer: &'a mut W, +} + +impl<W: ?Sized + Unpin> Unpin for Flush<'_, W> {} + +impl<'a, W: AsyncWrite + ?Sized + Unpin> Flush<'a, W> { + pub(super) fn new(writer: &'a mut W) -> Self { + Self { writer } + } +} + +impl<W> Future for Flush<'_, W> +where + W: AsyncWrite + ?Sized + Unpin, +{ + type Output = io::Result<()>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + Pin::new(&mut *self.writer).poll_flush(cx) + } +} diff --git a/third_party/rust/futures-util/src/io/into_sink.rs b/third_party/rust/futures-util/src/io/into_sink.rs new file mode 100644 index 0000000000..6a41ee2269 --- /dev/null +++ b/third_party/rust/futures-util/src/io/into_sink.rs @@ -0,0 +1,82 @@ +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncWrite; +use futures_sink::Sink; +use pin_project_lite::pin_project; +use std::io; +use std::pin::Pin; + +#[derive(Debug)] +struct Block<Item> { + offset: usize, + bytes: Item, +} + +pin_project! { + /// Sink for the [`into_sink`](super::AsyncWriteExt::into_sink) method. + #[must_use = "sinks do nothing unless polled"] + #[derive(Debug)] + #[cfg_attr(docsrs, doc(cfg(feature = "sink")))] + pub struct IntoSink<W, Item> { + #[pin] + writer: W, + // An outstanding block for us to push into the underlying writer, along with an offset of how + // far into this block we have written already. + buffer: Option<Block<Item>>, + } +} + +impl<W: AsyncWrite, Item: AsRef<[u8]>> IntoSink<W, Item> { + pub(super) fn new(writer: W) -> Self { + Self { writer, buffer: None } + } + + /// If we have an outstanding block in `buffer` attempt to push it into the writer, does _not_ + /// flush the writer after it succeeds in pushing the block into it. + fn poll_flush_buffer( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> Poll<Result<(), io::Error>> { + let mut this = self.project(); + + if let Some(buffer) = this.buffer { + loop { + let bytes = buffer.bytes.as_ref(); + let written = ready!(this.writer.as_mut().poll_write(cx, &bytes[buffer.offset..]))?; + buffer.offset += written; + if buffer.offset == bytes.len() { + break; + } + } + } + *this.buffer = None; + Poll::Ready(Ok(())) + } +} + +impl<W: AsyncWrite, Item: AsRef<[u8]>> Sink<Item> for IntoSink<W, Item> { + type Error = io::Error; + + fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.poll_flush_buffer(cx))?; + Poll::Ready(Ok(())) + } + + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + debug_assert!(self.buffer.is_none()); + *self.project().buffer = Some(Block { offset: 0, bytes: item }); + Ok(()) + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.as_mut().poll_flush_buffer(cx))?; + ready!(self.project().writer.poll_flush(cx))?; + Poll::Ready(Ok(())) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.as_mut().poll_flush_buffer(cx))?; + ready!(self.project().writer.poll_close(cx))?; + Poll::Ready(Ok(())) + } +} diff --git a/third_party/rust/futures-util/src/io/line_writer.rs b/third_party/rust/futures-util/src/io/line_writer.rs new file mode 100644 index 0000000000..71cd668325 --- /dev/null +++ b/third_party/rust/futures-util/src/io/line_writer.rs @@ -0,0 +1,155 @@ +use super::buf_writer::BufWriter; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncWrite; +use futures_io::IoSlice; +use pin_project_lite::pin_project; +use std::io; +use std::pin::Pin; + +pin_project! { +/// Wrap a writer, like [`BufWriter`] does, but prioritizes buffering lines +/// +/// This was written based on `std::io::LineWriter` which goes into further details +/// explaining the code. +/// +/// Buffering is actually done using `BufWriter`. This class will leverage `BufWriter` +/// to write on-each-line. +#[derive(Debug)] +pub struct LineWriter<W: AsyncWrite> { + #[pin] + buf_writer: BufWriter<W>, +} +} + +impl<W: AsyncWrite> LineWriter<W> { + /// Create a new `LineWriter` with default buffer capacity. The default is currently 1KB + /// which was taken from `std::io::LineWriter` + pub fn new(inner: W) -> LineWriter<W> { + LineWriter::with_capacity(1024, inner) + } + + /// Creates a new `LineWriter` with the specified buffer capacity. + pub fn with_capacity(capacity: usize, inner: W) -> LineWriter<W> { + LineWriter { buf_writer: BufWriter::with_capacity(capacity, inner) } + } + + /// Flush `buf_writer` if last char is "new line" + fn flush_if_completed_line(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + let this = self.project(); + match this.buf_writer.buffer().last().copied() { + Some(b'\n') => this.buf_writer.flush_buf(cx), + _ => Poll::Ready(Ok(())), + } + } + + /// Returns a reference to `buf_writer`'s internally buffered data. + pub fn buffer(&self) -> &[u8] { + self.buf_writer.buffer() + } + + /// Acquires a reference to the underlying sink or stream that this combinator is + /// pulling from. + pub fn get_ref(&self) -> &W { + self.buf_writer.get_ref() + } +} + +impl<W: AsyncWrite> AsyncWrite for LineWriter<W> { + fn poll_write( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &[u8], + ) -> Poll<io::Result<usize>> { + let mut this = self.as_mut().project(); + let newline_index = match memchr::memrchr(b'\n', buf) { + None => { + ready!(self.as_mut().flush_if_completed_line(cx)?); + return self.project().buf_writer.poll_write(cx, buf); + } + Some(newline_index) => newline_index + 1, + }; + + ready!(this.buf_writer.as_mut().poll_flush(cx)?); + + let lines = &buf[..newline_index]; + + let flushed = { ready!(this.buf_writer.as_mut().inner_poll_write(cx, lines))? }; + + if flushed == 0 { + return Poll::Ready(Ok(0)); + } + + let tail = if flushed >= newline_index { + &buf[flushed..] + } else if newline_index - flushed <= this.buf_writer.capacity() { + &buf[flushed..newline_index] + } else { + let scan_area = &buf[flushed..]; + let scan_area = &scan_area[..this.buf_writer.capacity()]; + match memchr::memrchr(b'\n', scan_area) { + Some(newline_index) => &scan_area[..newline_index + 1], + None => scan_area, + } + }; + + let buffered = this.buf_writer.as_mut().write_to_buf(tail); + Poll::Ready(Ok(flushed + buffered)) + } + + fn poll_write_vectored( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<io::Result<usize>> { + let mut this = self.as_mut().project(); + // `is_write_vectored()` is handled in original code, but not in this crate + // see https://github.com/rust-lang/rust/issues/70436 + + let last_newline_buf_idx = bufs + .iter() + .enumerate() + .rev() + .find_map(|(i, buf)| memchr::memchr(b'\n', buf).map(|_| i)); + let last_newline_buf_idx = match last_newline_buf_idx { + None => { + ready!(self.as_mut().flush_if_completed_line(cx)?); + return self.project().buf_writer.poll_write_vectored(cx, bufs); + } + Some(i) => i, + }; + + ready!(this.buf_writer.as_mut().poll_flush(cx)?); + + let (lines, tail) = bufs.split_at(last_newline_buf_idx + 1); + + let flushed = { ready!(this.buf_writer.as_mut().inner_poll_write_vectored(cx, lines))? }; + if flushed == 0 { + return Poll::Ready(Ok(0)); + } + + let lines_len = lines.iter().map(|buf| buf.len()).sum(); + if flushed < lines_len { + return Poll::Ready(Ok(flushed)); + } + + let buffered: usize = tail + .iter() + .filter(|buf| !buf.is_empty()) + .map(|buf| this.buf_writer.as_mut().write_to_buf(buf)) + .take_while(|&n| n > 0) + .sum(); + + Poll::Ready(Ok(flushed + buffered)) + } + + /// Forward to `buf_writer` 's `BufWriter::poll_flush()` + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + self.as_mut().project().buf_writer.poll_flush(cx) + } + + /// Forward to `buf_writer` 's `BufWriter::poll_close()` + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + self.as_mut().project().buf_writer.poll_close(cx) + } +} diff --git a/third_party/rust/futures-util/src/io/lines.rs b/third_party/rust/futures-util/src/io/lines.rs new file mode 100644 index 0000000000..b5561bfa7d --- /dev/null +++ b/third_party/rust/futures-util/src/io/lines.rs @@ -0,0 +1,47 @@ +use super::read_line::read_line_internal; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncBufRead; +use pin_project_lite::pin_project; +use std::io; +use std::mem; +use std::pin::Pin; + +pin_project! { + /// Stream for the [`lines`](super::AsyncBufReadExt::lines) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Lines<R> { + #[pin] + reader: R, + buf: String, + bytes: Vec<u8>, + read: usize, + } +} + +impl<R: AsyncBufRead> Lines<R> { + pub(super) fn new(reader: R) -> Self { + Self { reader, buf: String::new(), bytes: Vec::new(), read: 0 } + } +} + +impl<R: AsyncBufRead> Stream for Lines<R> { + type Item = io::Result<String>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let this = self.project(); + let n = ready!(read_line_internal(this.reader, cx, this.buf, this.bytes, this.read))?; + if n == 0 && this.buf.is_empty() { + return Poll::Ready(None); + } + if this.buf.ends_with('\n') { + this.buf.pop(); + if this.buf.ends_with('\r') { + this.buf.pop(); + } + } + Poll::Ready(Some(Ok(mem::take(this.buf)))) + } +} diff --git a/third_party/rust/futures-util/src/io/mod.rs b/third_party/rust/futures-util/src/io/mod.rs new file mode 100644 index 0000000000..8ce3ad644b --- /dev/null +++ b/third_party/rust/futures-util/src/io/mod.rs @@ -0,0 +1,841 @@ +//! Asynchronous I/O. +//! +//! This module is the asynchronous version of `std::io`. It defines four +//! traits, [`AsyncRead`], [`AsyncWrite`], [`AsyncSeek`], and [`AsyncBufRead`], +//! which mirror the `Read`, `Write`, `Seek`, and `BufRead` traits of the +//! standard library. However, these traits integrate with the asynchronous +//! task system, so that if an I/O object isn't ready for reading (or writing), +//! the thread is not blocked, and instead the current task is queued to be +//! woken when I/O is ready. +//! +//! In addition, the [`AsyncReadExt`], [`AsyncWriteExt`], [`AsyncSeekExt`], and +//! [`AsyncBufReadExt`] extension traits offer a variety of useful combinators +//! for operating with asynchronous I/O objects, including ways to work with +//! them using futures, streams and sinks. +//! +//! This module is only available when the `std` feature of this +//! library is activated, and it is activated by default. + +#[cfg(feature = "io-compat")] +#[cfg_attr(docsrs, doc(cfg(feature = "io-compat")))] +use crate::compat::Compat; +use crate::future::assert_future; +use crate::stream::assert_stream; +use std::{pin::Pin, ptr}; + +// Re-export some types from `std::io` so that users don't have to deal +// with conflicts when `use`ing `futures::io` and `std::io`. +#[doc(no_inline)] +pub use std::io::{Error, ErrorKind, IoSlice, IoSliceMut, Result, SeekFrom}; + +pub use futures_io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite}; + +// used by `BufReader` and `BufWriter` +// https://github.com/rust-lang/rust/blob/master/src/libstd/sys_common/io.rs#L1 +const DEFAULT_BUF_SIZE: usize = 8 * 1024; + +/// Initializes a buffer if necessary. +/// +/// A buffer is currently always initialized. +#[inline] +unsafe fn initialize<R: AsyncRead>(_reader: &R, buf: &mut [u8]) { + ptr::write_bytes(buf.as_mut_ptr(), 0, buf.len()) +} + +mod allow_std; +pub use self::allow_std::AllowStdIo; + +mod buf_reader; +pub use self::buf_reader::{BufReader, SeeKRelative}; + +mod buf_writer; +pub use self::buf_writer::BufWriter; + +mod line_writer; +pub use self::line_writer::LineWriter; + +mod chain; +pub use self::chain::Chain; + +mod close; +pub use self::close::Close; + +mod copy; +pub use self::copy::{copy, Copy}; + +mod copy_buf; +pub use self::copy_buf::{copy_buf, CopyBuf}; + +mod copy_buf_abortable; +pub use self::copy_buf_abortable::{copy_buf_abortable, CopyBufAbortable}; + +mod cursor; +pub use self::cursor::Cursor; + +mod empty; +pub use self::empty::{empty, Empty}; + +mod fill_buf; +pub use self::fill_buf::FillBuf; + +mod flush; +pub use self::flush::Flush; + +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +mod into_sink; +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub use self::into_sink::IntoSink; + +mod lines; +pub use self::lines::Lines; + +mod read; +pub use self::read::Read; + +mod read_vectored; +pub use self::read_vectored::ReadVectored; + +mod read_exact; +pub use self::read_exact::ReadExact; + +mod read_line; +pub use self::read_line::ReadLine; + +mod read_to_end; +pub use self::read_to_end::ReadToEnd; + +mod read_to_string; +pub use self::read_to_string::ReadToString; + +mod read_until; +pub use self::read_until::ReadUntil; + +mod repeat; +pub use self::repeat::{repeat, Repeat}; + +mod seek; +pub use self::seek::Seek; + +mod sink; +pub use self::sink::{sink, Sink}; + +mod split; +pub use self::split::{ReadHalf, ReuniteError, WriteHalf}; + +mod take; +pub use self::take::Take; + +mod window; +pub use self::window::Window; + +mod write; +pub use self::write::Write; + +mod write_vectored; +pub use self::write_vectored::WriteVectored; + +mod write_all; +pub use self::write_all::WriteAll; + +#[cfg(feature = "write-all-vectored")] +mod write_all_vectored; +#[cfg(feature = "write-all-vectored")] +pub use self::write_all_vectored::WriteAllVectored; + +/// An extension trait which adds utility methods to `AsyncRead` types. +pub trait AsyncReadExt: AsyncRead { + /// Creates an adaptor which will chain this stream with another. + /// + /// The returned `AsyncRead` instance will first read all bytes from this object + /// until EOF is encountered. Afterwards the output is equivalent to the + /// output of `next`. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncReadExt, Cursor}; + /// + /// let reader1 = Cursor::new([1, 2, 3, 4]); + /// let reader2 = Cursor::new([5, 6, 7, 8]); + /// + /// let mut reader = reader1.chain(reader2); + /// let mut buffer = Vec::new(); + /// + /// // read the value into a Vec. + /// reader.read_to_end(&mut buffer).await?; + /// assert_eq!(buffer, [1, 2, 3, 4, 5, 6, 7, 8]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn chain<R>(self, next: R) -> Chain<Self, R> + where + Self: Sized, + R: AsyncRead, + { + assert_read(Chain::new(self, next)) + } + + /// Tries to read some bytes directly into the given `buf` in asynchronous + /// manner, returning a future type. + /// + /// The returned future will resolve to the number of bytes read once the read + /// operation is completed. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncReadExt, Cursor}; + /// + /// let mut reader = Cursor::new([1, 2, 3, 4]); + /// let mut output = [0u8; 5]; + /// + /// let bytes = reader.read(&mut output[..]).await?; + /// + /// // This is only guaranteed to be 4 because `&[u8]` is a synchronous + /// // reader. In a real system you could get anywhere from 1 to + /// // `output.len()` bytes in a single read. + /// assert_eq!(bytes, 4); + /// assert_eq!(output, [1, 2, 3, 4, 0]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Read<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<usize>, _>(Read::new(self, buf)) + } + + /// Creates a future which will read from the `AsyncRead` into `bufs` using vectored + /// IO operations. + /// + /// The returned future will resolve to the number of bytes read once the read + /// operation is completed. + fn read_vectored<'a>(&'a mut self, bufs: &'a mut [IoSliceMut<'a>]) -> ReadVectored<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<usize>, _>(ReadVectored::new(self, bufs)) + } + + /// Creates a future which will read exactly enough bytes to fill `buf`, + /// returning an error if end of file (EOF) is hit sooner. + /// + /// The returned future will resolve once the read operation is completed. + /// + /// In the case of an error the buffer and the object will be discarded, with + /// the error yielded. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncReadExt, Cursor}; + /// + /// let mut reader = Cursor::new([1, 2, 3, 4]); + /// let mut output = [0u8; 4]; + /// + /// reader.read_exact(&mut output).await?; + /// + /// assert_eq!(output, [1, 2, 3, 4]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + /// + /// ## EOF is hit before `buf` is filled + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{self, AsyncReadExt, Cursor}; + /// + /// let mut reader = Cursor::new([1, 2, 3, 4]); + /// let mut output = [0u8; 5]; + /// + /// let result = reader.read_exact(&mut output).await; + /// + /// assert_eq!(result.unwrap_err().kind(), io::ErrorKind::UnexpectedEof); + /// # }); + /// ``` + fn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExact<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<()>, _>(ReadExact::new(self, buf)) + } + + /// Creates a future which will read all the bytes from this `AsyncRead`. + /// + /// On success the total number of bytes read is returned. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncReadExt, Cursor}; + /// + /// let mut reader = Cursor::new([1, 2, 3, 4]); + /// let mut output = Vec::with_capacity(4); + /// + /// let bytes = reader.read_to_end(&mut output).await?; + /// + /// assert_eq!(bytes, 4); + /// assert_eq!(output, vec![1, 2, 3, 4]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn read_to_end<'a>(&'a mut self, buf: &'a mut Vec<u8>) -> ReadToEnd<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<usize>, _>(ReadToEnd::new(self, buf)) + } + + /// Creates a future which will read all the bytes from this `AsyncRead`. + /// + /// On success the total number of bytes read is returned. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncReadExt, Cursor}; + /// + /// let mut reader = Cursor::new(&b"1234"[..]); + /// let mut buffer = String::with_capacity(4); + /// + /// let bytes = reader.read_to_string(&mut buffer).await?; + /// + /// assert_eq!(bytes, 4); + /// assert_eq!(buffer, String::from("1234")); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn read_to_string<'a>(&'a mut self, buf: &'a mut String) -> ReadToString<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<usize>, _>(ReadToString::new(self, buf)) + } + + /// Helper method for splitting this read/write object into two halves. + /// + /// The two halves returned implement the `AsyncRead` and `AsyncWrite` + /// traits, respectively. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{self, AsyncReadExt, Cursor}; + /// + /// // Note that for `Cursor` the read and write halves share a single + /// // seek position. This may or may not be true for other types that + /// // implement both `AsyncRead` and `AsyncWrite`. + /// + /// let reader = Cursor::new([1, 2, 3, 4]); + /// let mut buffer = Cursor::new(vec![0, 0, 0, 0, 5, 6, 7, 8]); + /// let mut writer = Cursor::new(vec![0u8; 5]); + /// + /// { + /// let (buffer_reader, mut buffer_writer) = (&mut buffer).split(); + /// io::copy(reader, &mut buffer_writer).await?; + /// io::copy(buffer_reader, &mut writer).await?; + /// } + /// + /// assert_eq!(buffer.into_inner(), [1, 2, 3, 4, 5, 6, 7, 8]); + /// assert_eq!(writer.into_inner(), [5, 6, 7, 8, 0]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn split(self) -> (ReadHalf<Self>, WriteHalf<Self>) + where + Self: AsyncWrite + Sized, + { + let (r, w) = split::split(self); + (assert_read(r), assert_write(w)) + } + + /// Creates an AsyncRead adapter which will read at most `limit` bytes + /// from the underlying reader. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncReadExt, Cursor}; + /// + /// let reader = Cursor::new(&b"12345678"[..]); + /// let mut buffer = [0; 5]; + /// + /// let mut take = reader.take(4); + /// let n = take.read(&mut buffer).await?; + /// + /// assert_eq!(n, 4); + /// assert_eq!(&buffer, b"1234\0"); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn take(self, limit: u64) -> Take<Self> + where + Self: Sized, + { + assert_read(Take::new(self, limit)) + } + + /// Wraps an [`AsyncRead`] in a compatibility wrapper that allows it to be + /// used as a futures 0.1 / tokio-io 0.1 `AsyncRead`. If the wrapped type + /// implements [`AsyncWrite`] as well, the result will also implement the + /// futures 0.1 / tokio 0.1 `AsyncWrite` trait. + /// + /// Requires the `io-compat` feature to enable. + #[cfg(feature = "io-compat")] + #[cfg_attr(docsrs, doc(cfg(feature = "io-compat")))] + fn compat(self) -> Compat<Self> + where + Self: Sized + Unpin, + { + Compat::new(self) + } +} + +impl<R: AsyncRead + ?Sized> AsyncReadExt for R {} + +/// An extension trait which adds utility methods to `AsyncWrite` types. +pub trait AsyncWriteExt: AsyncWrite { + /// Creates a future which will entirely flush this `AsyncWrite`. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AllowStdIo, AsyncWriteExt}; + /// use std::io::{BufWriter, Cursor}; + /// + /// let mut output = vec![0u8; 5]; + /// + /// { + /// let writer = Cursor::new(&mut output); + /// let mut buffered = AllowStdIo::new(BufWriter::new(writer)); + /// buffered.write_all(&[1, 2]).await?; + /// buffered.write_all(&[3, 4]).await?; + /// buffered.flush().await?; + /// } + /// + /// assert_eq!(output, [1, 2, 3, 4, 0]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn flush(&mut self) -> Flush<'_, Self> + where + Self: Unpin, + { + assert_future::<Result<()>, _>(Flush::new(self)) + } + + /// Creates a future which will entirely close this `AsyncWrite`. + fn close(&mut self) -> Close<'_, Self> + where + Self: Unpin, + { + assert_future::<Result<()>, _>(Close::new(self)) + } + + /// Creates a future which will write bytes from `buf` into the object. + /// + /// The returned future will resolve to the number of bytes written once the write + /// operation is completed. + fn write<'a>(&'a mut self, buf: &'a [u8]) -> Write<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<usize>, _>(Write::new(self, buf)) + } + + /// Creates a future which will write bytes from `bufs` into the object using vectored + /// IO operations. + /// + /// The returned future will resolve to the number of bytes written once the write + /// operation is completed. + fn write_vectored<'a>(&'a mut self, bufs: &'a [IoSlice<'a>]) -> WriteVectored<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<usize>, _>(WriteVectored::new(self, bufs)) + } + + /// Write data into this object. + /// + /// Creates a future that will write the entire contents of the buffer `buf` into + /// this `AsyncWrite`. + /// + /// The returned future will not complete until all the data has been written. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncWriteExt, Cursor}; + /// + /// let mut writer = Cursor::new(vec![0u8; 5]); + /// + /// writer.write_all(&[1, 2, 3, 4]).await?; + /// + /// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn write_all<'a>(&'a mut self, buf: &'a [u8]) -> WriteAll<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<()>, _>(WriteAll::new(self, buf)) + } + + /// Attempts to write multiple buffers into this writer. + /// + /// Creates a future that will write the entire contents of `bufs` into this + /// `AsyncWrite` using [vectored writes]. + /// + /// The returned future will not complete until all the data has been + /// written. + /// + /// [vectored writes]: std::io::Write::write_vectored + /// + /// # Notes + /// + /// Unlike `io::Write::write_vectored`, this takes a *mutable* reference to + /// a slice of `IoSlice`s, not an immutable one. That's because we need to + /// modify the slice to keep track of the bytes already written. + /// + /// Once this futures returns, the contents of `bufs` are unspecified, as + /// this depends on how many calls to `write_vectored` were necessary. It is + /// best to understand this function as taking ownership of `bufs` and to + /// not use `bufs` afterwards. The underlying buffers, to which the + /// `IoSlice`s point (but not the `IoSlice`s themselves), are unchanged and + /// can be reused. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::AsyncWriteExt; + /// use futures_util::io::Cursor; + /// use std::io::IoSlice; + /// + /// let mut writer = Cursor::new(Vec::new()); + /// let bufs = &mut [ + /// IoSlice::new(&[1]), + /// IoSlice::new(&[2, 3]), + /// IoSlice::new(&[4, 5, 6]), + /// ]; + /// + /// writer.write_all_vectored(bufs).await?; + /// // Note: the contents of `bufs` is now unspecified, see the Notes section. + /// + /// assert_eq!(writer.into_inner(), &[1, 2, 3, 4, 5, 6]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + #[cfg(feature = "write-all-vectored")] + fn write_all_vectored<'a>( + &'a mut self, + bufs: &'a mut [IoSlice<'a>], + ) -> WriteAllVectored<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<()>, _>(WriteAllVectored::new(self, bufs)) + } + + /// Wraps an [`AsyncWrite`] in a compatibility wrapper that allows it to be + /// used as a futures 0.1 / tokio-io 0.1 `AsyncWrite`. + /// Requires the `io-compat` feature to enable. + #[cfg(feature = "io-compat")] + #[cfg_attr(docsrs, doc(cfg(feature = "io-compat")))] + fn compat_write(self) -> Compat<Self> + where + Self: Sized + Unpin, + { + Compat::new(self) + } + + /// Allow using an [`AsyncWrite`] as a [`Sink`](futures_sink::Sink)`<Item: AsRef<[u8]>>`. + /// + /// This adapter produces a sink that will write each value passed to it + /// into the underlying writer. + /// + /// Note that this function consumes the given writer, returning a wrapped + /// version. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::AsyncWriteExt; + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(vec![Ok([1, 2, 3]), Ok([4, 5, 6])]); + /// + /// let mut writer = vec![]; + /// + /// stream.forward((&mut writer).into_sink()).await?; + /// + /// assert_eq!(writer, vec![1, 2, 3, 4, 5, 6]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) + /// # })?; + /// # Ok::<(), Box<dyn std::error::Error>>(()) + /// ``` + #[cfg(feature = "sink")] + #[cfg_attr(docsrs, doc(cfg(feature = "sink")))] + fn into_sink<Item: AsRef<[u8]>>(self) -> IntoSink<Self, Item> + where + Self: Sized, + { + crate::sink::assert_sink::<Item, Error, _>(IntoSink::new(self)) + } +} + +impl<W: AsyncWrite + ?Sized> AsyncWriteExt for W {} + +/// An extension trait which adds utility methods to `AsyncSeek` types. +pub trait AsyncSeekExt: AsyncSeek { + /// Creates a future which will seek an IO object, and then yield the + /// new position in the object and the object itself. + /// + /// In the case of an error the buffer and the object will be discarded, with + /// the error yielded. + fn seek(&mut self, pos: SeekFrom) -> Seek<'_, Self> + where + Self: Unpin, + { + assert_future::<Result<u64>, _>(Seek::new(self, pos)) + } + + /// Creates a future which will return the current seek position from the + /// start of the stream. + /// + /// This is equivalent to `self.seek(SeekFrom::Current(0))`. + fn stream_position(&mut self) -> Seek<'_, Self> + where + Self: Unpin, + { + self.seek(SeekFrom::Current(0)) + } +} + +impl<S: AsyncSeek + ?Sized> AsyncSeekExt for S {} + +/// An extension trait which adds utility methods to `AsyncBufRead` types. +pub trait AsyncBufReadExt: AsyncBufRead { + /// Creates a future which will wait for a non-empty buffer to be available from this I/O + /// object or EOF to be reached. + /// + /// This method is the async equivalent to [`BufRead::fill_buf`](std::io::BufRead::fill_buf). + /// + /// ```rust + /// # futures::executor::block_on(async { + /// use futures::{io::AsyncBufReadExt as _, stream::{iter, TryStreamExt as _}}; + /// + /// let mut stream = iter(vec![Ok(vec![1, 2, 3]), Ok(vec![4, 5, 6])]).into_async_read(); + /// + /// assert_eq!(stream.fill_buf().await?, vec![1, 2, 3]); + /// stream.consume_unpin(2); + /// + /// assert_eq!(stream.fill_buf().await?, vec![3]); + /// stream.consume_unpin(1); + /// + /// assert_eq!(stream.fill_buf().await?, vec![4, 5, 6]); + /// stream.consume_unpin(3); + /// + /// assert_eq!(stream.fill_buf().await?, vec![]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn fill_buf(&mut self) -> FillBuf<'_, Self> + where + Self: Unpin, + { + assert_future::<Result<&[u8]>, _>(FillBuf::new(self)) + } + + /// A convenience for calling [`AsyncBufRead::consume`] on [`Unpin`] IO types. + /// + /// ```rust + /// # futures::executor::block_on(async { + /// use futures::{io::AsyncBufReadExt as _, stream::{iter, TryStreamExt as _}}; + /// + /// let mut stream = iter(vec![Ok(vec![1, 2, 3])]).into_async_read(); + /// + /// assert_eq!(stream.fill_buf().await?, vec![1, 2, 3]); + /// stream.consume_unpin(2); + /// + /// assert_eq!(stream.fill_buf().await?, vec![3]); + /// stream.consume_unpin(1); + /// + /// assert_eq!(stream.fill_buf().await?, vec![]); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn consume_unpin(&mut self, amt: usize) + where + Self: Unpin, + { + Pin::new(self).consume(amt) + } + + /// Creates a future which will read all the bytes associated with this I/O + /// object into `buf` until the delimiter `byte` or EOF is reached. + /// This method is the async equivalent to [`BufRead::read_until`](std::io::BufRead::read_until). + /// + /// This function will read bytes from the underlying stream until the + /// delimiter or EOF is found. Once found, all bytes up to, and including, + /// the delimiter (if found) will be appended to `buf`. + /// + /// The returned future will resolve to the number of bytes read once the read + /// operation is completed. + /// + /// In the case of an error the buffer and the object will be discarded, with + /// the error yielded. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncBufReadExt, Cursor}; + /// + /// let mut cursor = Cursor::new(b"lorem-ipsum"); + /// let mut buf = vec![]; + /// + /// // cursor is at 'l' + /// let num_bytes = cursor.read_until(b'-', &mut buf).await?; + /// assert_eq!(num_bytes, 6); + /// assert_eq!(buf, b"lorem-"); + /// buf.clear(); + /// + /// // cursor is at 'i' + /// let num_bytes = cursor.read_until(b'-', &mut buf).await?; + /// assert_eq!(num_bytes, 5); + /// assert_eq!(buf, b"ipsum"); + /// buf.clear(); + /// + /// // cursor is at EOF + /// let num_bytes = cursor.read_until(b'-', &mut buf).await?; + /// assert_eq!(num_bytes, 0); + /// assert_eq!(buf, b""); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn read_until<'a>(&'a mut self, byte: u8, buf: &'a mut Vec<u8>) -> ReadUntil<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<usize>, _>(ReadUntil::new(self, byte, buf)) + } + + /// Creates a future which will read all the bytes associated with this I/O + /// object into `buf` until a newline (the 0xA byte) or EOF is reached, + /// This method is the async equivalent to [`BufRead::read_line`](std::io::BufRead::read_line). + /// + /// This function will read bytes from the underlying stream until the + /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes + /// up to, and including, the delimiter (if found) will be appended to + /// `buf`. + /// + /// The returned future will resolve to the number of bytes read once the read + /// operation is completed. + /// + /// In the case of an error the buffer and the object will be discarded, with + /// the error yielded. + /// + /// # Errors + /// + /// This function has the same error semantics as [`read_until`] and will + /// also return an error if the read bytes are not valid UTF-8. If an I/O + /// error is encountered then `buf` may contain some bytes already read in + /// the event that all data read so far was valid UTF-8. + /// + /// [`read_until`]: AsyncBufReadExt::read_until + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncBufReadExt, Cursor}; + /// + /// let mut cursor = Cursor::new(b"foo\nbar"); + /// let mut buf = String::new(); + /// + /// // cursor is at 'f' + /// let num_bytes = cursor.read_line(&mut buf).await?; + /// assert_eq!(num_bytes, 4); + /// assert_eq!(buf, "foo\n"); + /// buf.clear(); + /// + /// // cursor is at 'b' + /// let num_bytes = cursor.read_line(&mut buf).await?; + /// assert_eq!(num_bytes, 3); + /// assert_eq!(buf, "bar"); + /// buf.clear(); + /// + /// // cursor is at EOF + /// let num_bytes = cursor.read_line(&mut buf).await?; + /// assert_eq!(num_bytes, 0); + /// assert_eq!(buf, ""); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self> + where + Self: Unpin, + { + assert_future::<Result<usize>, _>(ReadLine::new(self, buf)) + } + + /// Returns a stream over the lines of this reader. + /// This method is the async equivalent to [`BufRead::lines`](std::io::BufRead::lines). + /// + /// The stream returned from this function will yield instances of + /// [`io::Result`]`<`[`String`]`>`. Each string returned will *not* have a newline + /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end. + /// + /// [`io::Result`]: std::io::Result + /// [`String`]: String + /// + /// # Errors + /// + /// Each line of the stream has the same error semantics as [`AsyncBufReadExt::read_line`]. + /// + /// [`AsyncBufReadExt::read_line`]: AsyncBufReadExt::read_line + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncBufReadExt, Cursor}; + /// use futures::stream::StreamExt; + /// + /// let cursor = Cursor::new(b"lorem\nipsum\r\ndolor"); + /// + /// let mut lines_stream = cursor.lines().map(|l| l.unwrap()); + /// assert_eq!(lines_stream.next().await, Some(String::from("lorem"))); + /// assert_eq!(lines_stream.next().await, Some(String::from("ipsum"))); + /// assert_eq!(lines_stream.next().await, Some(String::from("dolor"))); + /// assert_eq!(lines_stream.next().await, None); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + fn lines(self) -> Lines<Self> + where + Self: Sized, + { + assert_stream::<Result<String>, _>(Lines::new(self)) + } +} + +impl<R: AsyncBufRead + ?Sized> AsyncBufReadExt for R {} + +// Just a helper function to ensure the reader we're returning all have the +// right implementations. +pub(crate) fn assert_read<R>(reader: R) -> R +where + R: AsyncRead, +{ + reader +} +// Just a helper function to ensure the writer we're returning all have the +// right implementations. +pub(crate) fn assert_write<W>(writer: W) -> W +where + W: AsyncWrite, +{ + writer +} diff --git a/third_party/rust/futures-util/src/io/read.rs b/third_party/rust/futures-util/src/io/read.rs new file mode 100644 index 0000000000..677ba818d9 --- /dev/null +++ b/third_party/rust/futures-util/src/io/read.rs @@ -0,0 +1,30 @@ +use crate::io::AsyncRead; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use std::io; +use std::pin::Pin; + +/// Future for the [`read`](super::AsyncReadExt::read) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Read<'a, R: ?Sized> { + reader: &'a mut R, + buf: &'a mut [u8], +} + +impl<R: ?Sized + Unpin> Unpin for Read<'_, R> {} + +impl<'a, R: AsyncRead + ?Sized + Unpin> Read<'a, R> { + pub(super) fn new(reader: &'a mut R, buf: &'a mut [u8]) -> Self { + Self { reader, buf } + } +} + +impl<R: AsyncRead + ?Sized + Unpin> Future for Read<'_, R> { + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + Pin::new(&mut this.reader).poll_read(cx, this.buf) + } +} diff --git a/third_party/rust/futures-util/src/io/read_exact.rs b/third_party/rust/futures-util/src/io/read_exact.rs new file mode 100644 index 0000000000..cd0b20e597 --- /dev/null +++ b/third_party/rust/futures-util/src/io/read_exact.rs @@ -0,0 +1,42 @@ +use crate::io::AsyncRead; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use std::io; +use std::mem; +use std::pin::Pin; + +/// Future for the [`read_exact`](super::AsyncReadExt::read_exact) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ReadExact<'a, R: ?Sized> { + reader: &'a mut R, + buf: &'a mut [u8], +} + +impl<R: ?Sized + Unpin> Unpin for ReadExact<'_, R> {} + +impl<'a, R: AsyncRead + ?Sized + Unpin> ReadExact<'a, R> { + pub(super) fn new(reader: &'a mut R, buf: &'a mut [u8]) -> Self { + Self { reader, buf } + } +} + +impl<R: AsyncRead + ?Sized + Unpin> Future for ReadExact<'_, R> { + type Output = io::Result<()>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + while !this.buf.is_empty() { + let n = ready!(Pin::new(&mut this.reader).poll_read(cx, this.buf))?; + { + let (_, rest) = mem::take(&mut this.buf).split_at_mut(n); + this.buf = rest; + } + if n == 0 { + return Poll::Ready(Err(io::ErrorKind::UnexpectedEof.into())); + } + } + Poll::Ready(Ok(())) + } +} diff --git a/third_party/rust/futures-util/src/io/read_line.rs b/third_party/rust/futures-util/src/io/read_line.rs new file mode 100644 index 0000000000..e1b8fc9455 --- /dev/null +++ b/third_party/rust/futures-util/src/io/read_line.rs @@ -0,0 +1,57 @@ +use super::read_until::read_until_internal; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncBufRead; +use std::io; +use std::mem; +use std::pin::Pin; +use std::str; + +/// Future for the [`read_line`](super::AsyncBufReadExt::read_line) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ReadLine<'a, R: ?Sized> { + reader: &'a mut R, + buf: &'a mut String, + bytes: Vec<u8>, + read: usize, +} + +impl<R: ?Sized + Unpin> Unpin for ReadLine<'_, R> {} + +impl<'a, R: AsyncBufRead + ?Sized + Unpin> ReadLine<'a, R> { + pub(super) fn new(reader: &'a mut R, buf: &'a mut String) -> Self { + Self { reader, bytes: mem::take(buf).into_bytes(), buf, read: 0 } + } +} + +pub(super) fn read_line_internal<R: AsyncBufRead + ?Sized>( + reader: Pin<&mut R>, + cx: &mut Context<'_>, + buf: &mut String, + bytes: &mut Vec<u8>, + read: &mut usize, +) -> Poll<io::Result<usize>> { + let ret = ready!(read_until_internal(reader, cx, b'\n', bytes, read)); + if str::from_utf8(bytes).is_err() { + Poll::Ready(ret.and_then(|_| { + Err(io::Error::new(io::ErrorKind::InvalidData, "stream did not contain valid UTF-8")) + })) + } else { + debug_assert!(buf.is_empty()); + debug_assert_eq!(*read, 0); + // Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`. + mem::swap(unsafe { buf.as_mut_vec() }, bytes); + Poll::Ready(ret) + } +} + +impl<R: AsyncBufRead + ?Sized + Unpin> Future for ReadLine<'_, R> { + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let Self { reader, buf, bytes, read } = &mut *self; + read_line_internal(Pin::new(reader), cx, buf, bytes, read) + } +} diff --git a/third_party/rust/futures-util/src/io/read_to_end.rs b/third_party/rust/futures-util/src/io/read_to_end.rs new file mode 100644 index 0000000000..919d7d13c7 --- /dev/null +++ b/third_party/rust/futures-util/src/io/read_to_end.rs @@ -0,0 +1,91 @@ +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncRead; +use std::io; +use std::pin::Pin; +use std::vec::Vec; + +/// Future for the [`read_to_end`](super::AsyncReadExt::read_to_end) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ReadToEnd<'a, R: ?Sized> { + reader: &'a mut R, + buf: &'a mut Vec<u8>, + start_len: usize, +} + +impl<R: ?Sized + Unpin> Unpin for ReadToEnd<'_, R> {} + +impl<'a, R: AsyncRead + ?Sized + Unpin> ReadToEnd<'a, R> { + pub(super) fn new(reader: &'a mut R, buf: &'a mut Vec<u8>) -> Self { + let start_len = buf.len(); + Self { reader, buf, start_len } + } +} + +struct Guard<'a> { + buf: &'a mut Vec<u8>, + len: usize, +} + +impl Drop for Guard<'_> { + fn drop(&mut self) { + unsafe { + self.buf.set_len(self.len); + } + } +} + +// This uses an adaptive system to extend the vector when it fills. We want to +// avoid paying to allocate and zero a huge chunk of memory if the reader only +// has 4 bytes while still making large reads if the reader does have a ton +// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every +// time is 4,500 times (!) slower than this if the reader has a very small +// amount of data to return. +// +// Because we're extending the buffer with uninitialized data for trusted +// readers, we need to make sure to truncate that if any of this panics. +pub(super) fn read_to_end_internal<R: AsyncRead + ?Sized>( + mut rd: Pin<&mut R>, + cx: &mut Context<'_>, + buf: &mut Vec<u8>, + start_len: usize, +) -> Poll<io::Result<usize>> { + let mut g = Guard { len: buf.len(), buf }; + loop { + if g.len == g.buf.len() { + unsafe { + g.buf.reserve(32); + let capacity = g.buf.capacity(); + g.buf.set_len(capacity); + super::initialize(&rd, &mut g.buf[g.len..]); + } + } + + let buf = &mut g.buf[g.len..]; + match ready!(rd.as_mut().poll_read(cx, buf)) { + Ok(0) => return Poll::Ready(Ok(g.len - start_len)), + Ok(n) => { + // We can't allow bogus values from read. If it is too large, the returned vec could have its length + // set past its capacity, or if it overflows the vec could be shortened which could create an invalid + // string if this is called via read_to_string. + assert!(n <= buf.len()); + g.len += n; + } + Err(e) => return Poll::Ready(Err(e)), + } + } +} + +impl<A> Future for ReadToEnd<'_, A> +where + A: AsyncRead + ?Sized + Unpin, +{ + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + read_to_end_internal(Pin::new(&mut this.reader), cx, this.buf, this.start_len) + } +} diff --git a/third_party/rust/futures-util/src/io/read_to_string.rs b/third_party/rust/futures-util/src/io/read_to_string.rs new file mode 100644 index 0000000000..c175396d81 --- /dev/null +++ b/third_party/rust/futures-util/src/io/read_to_string.rs @@ -0,0 +1,59 @@ +use super::read_to_end::read_to_end_internal; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncRead; +use std::pin::Pin; +use std::vec::Vec; +use std::{io, mem, str}; + +/// Future for the [`read_to_string`](super::AsyncReadExt::read_to_string) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ReadToString<'a, R: ?Sized> { + reader: &'a mut R, + buf: &'a mut String, + bytes: Vec<u8>, + start_len: usize, +} + +impl<R: ?Sized + Unpin> Unpin for ReadToString<'_, R> {} + +impl<'a, R: AsyncRead + ?Sized + Unpin> ReadToString<'a, R> { + pub(super) fn new(reader: &'a mut R, buf: &'a mut String) -> Self { + let start_len = buf.len(); + Self { reader, bytes: mem::take(buf).into_bytes(), buf, start_len } + } +} + +fn read_to_string_internal<R: AsyncRead + ?Sized>( + reader: Pin<&mut R>, + cx: &mut Context<'_>, + buf: &mut String, + bytes: &mut Vec<u8>, + start_len: usize, +) -> Poll<io::Result<usize>> { + let ret = ready!(read_to_end_internal(reader, cx, bytes, start_len)); + if str::from_utf8(bytes).is_err() { + Poll::Ready(ret.and_then(|_| { + Err(io::Error::new(io::ErrorKind::InvalidData, "stream did not contain valid UTF-8")) + })) + } else { + debug_assert!(buf.is_empty()); + // Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`. + mem::swap(unsafe { buf.as_mut_vec() }, bytes); + Poll::Ready(ret) + } +} + +impl<A> Future for ReadToString<'_, A> +where + A: AsyncRead + ?Sized + Unpin, +{ + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let Self { reader, buf, bytes, start_len } = &mut *self; + read_to_string_internal(Pin::new(reader), cx, buf, bytes, *start_len) + } +} diff --git a/third_party/rust/futures-util/src/io/read_until.rs b/third_party/rust/futures-util/src/io/read_until.rs new file mode 100644 index 0000000000..72b59eab13 --- /dev/null +++ b/third_party/rust/futures-util/src/io/read_until.rs @@ -0,0 +1,60 @@ +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncBufRead; +use std::io; +use std::mem; +use std::pin::Pin; + +/// Future for the [`read_until`](super::AsyncBufReadExt::read_until) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ReadUntil<'a, R: ?Sized> { + reader: &'a mut R, + byte: u8, + buf: &'a mut Vec<u8>, + read: usize, +} + +impl<R: ?Sized + Unpin> Unpin for ReadUntil<'_, R> {} + +impl<'a, R: AsyncBufRead + ?Sized + Unpin> ReadUntil<'a, R> { + pub(super) fn new(reader: &'a mut R, byte: u8, buf: &'a mut Vec<u8>) -> Self { + Self { reader, byte, buf, read: 0 } + } +} + +pub(super) fn read_until_internal<R: AsyncBufRead + ?Sized>( + mut reader: Pin<&mut R>, + cx: &mut Context<'_>, + byte: u8, + buf: &mut Vec<u8>, + read: &mut usize, +) -> Poll<io::Result<usize>> { + loop { + let (done, used) = { + let available = ready!(reader.as_mut().poll_fill_buf(cx))?; + if let Some(i) = memchr::memchr(byte, available) { + buf.extend_from_slice(&available[..=i]); + (true, i + 1) + } else { + buf.extend_from_slice(available); + (false, available.len()) + } + }; + reader.as_mut().consume(used); + *read += used; + if done || used == 0 { + return Poll::Ready(Ok(mem::replace(read, 0))); + } + } +} + +impl<R: AsyncBufRead + ?Sized + Unpin> Future for ReadUntil<'_, R> { + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let Self { reader, byte, buf, read } = &mut *self; + read_until_internal(Pin::new(reader), cx, *byte, buf, read) + } +} diff --git a/third_party/rust/futures-util/src/io/read_vectored.rs b/third_party/rust/futures-util/src/io/read_vectored.rs new file mode 100644 index 0000000000..4e22df57e9 --- /dev/null +++ b/third_party/rust/futures-util/src/io/read_vectored.rs @@ -0,0 +1,30 @@ +use crate::io::AsyncRead; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use std::io::{self, IoSliceMut}; +use std::pin::Pin; + +/// Future for the [`read_vectored`](super::AsyncReadExt::read_vectored) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ReadVectored<'a, R: ?Sized> { + reader: &'a mut R, + bufs: &'a mut [IoSliceMut<'a>], +} + +impl<R: ?Sized + Unpin> Unpin for ReadVectored<'_, R> {} + +impl<'a, R: AsyncRead + ?Sized + Unpin> ReadVectored<'a, R> { + pub(super) fn new(reader: &'a mut R, bufs: &'a mut [IoSliceMut<'a>]) -> Self { + Self { reader, bufs } + } +} + +impl<R: AsyncRead + ?Sized + Unpin> Future for ReadVectored<'_, R> { + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + Pin::new(&mut this.reader).poll_read_vectored(cx, this.bufs) + } +} diff --git a/third_party/rust/futures-util/src/io/repeat.rs b/third_party/rust/futures-util/src/io/repeat.rs new file mode 100644 index 0000000000..2828bf0114 --- /dev/null +++ b/third_party/rust/futures-util/src/io/repeat.rs @@ -0,0 +1,66 @@ +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncRead, IoSliceMut}; +use std::fmt; +use std::io; +use std::pin::Pin; + +/// Reader for the [`repeat()`] function. +#[must_use = "readers do nothing unless polled"] +pub struct Repeat { + byte: u8, +} + +/// Creates an instance of a reader that infinitely repeats one byte. +/// +/// All reads from this reader will succeed by filling the specified buffer with +/// the given byte. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::io::{self, AsyncReadExt}; +/// +/// let mut buffer = [0; 3]; +/// let mut reader = io::repeat(0b101); +/// reader.read_exact(&mut buffer).await.unwrap(); +/// assert_eq!(buffer, [0b101, 0b101, 0b101]); +/// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); +/// ``` +pub fn repeat(byte: u8) -> Repeat { + Repeat { byte } +} + +impl AsyncRead for Repeat { + #[inline] + fn poll_read( + self: Pin<&mut Self>, + _: &mut Context<'_>, + buf: &mut [u8], + ) -> Poll<io::Result<usize>> { + for slot in &mut *buf { + *slot = self.byte; + } + Poll::Ready(Ok(buf.len())) + } + + #[inline] + fn poll_read_vectored( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &mut [IoSliceMut<'_>], + ) -> Poll<io::Result<usize>> { + let mut nwritten = 0; + for buf in bufs { + nwritten += ready!(self.as_mut().poll_read(cx, buf))?; + } + Poll::Ready(Ok(nwritten)) + } +} + +impl fmt::Debug for Repeat { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.pad("Repeat { .. }") + } +} diff --git a/third_party/rust/futures-util/src/io/seek.rs b/third_party/rust/futures-util/src/io/seek.rs new file mode 100644 index 0000000000..0aa2371393 --- /dev/null +++ b/third_party/rust/futures-util/src/io/seek.rs @@ -0,0 +1,30 @@ +use crate::io::{AsyncSeek, SeekFrom}; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use std::io; +use std::pin::Pin; + +/// Future for the [`seek`](crate::io::AsyncSeekExt::seek) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Seek<'a, S: ?Sized> { + seek: &'a mut S, + pos: SeekFrom, +} + +impl<S: ?Sized + Unpin> Unpin for Seek<'_, S> {} + +impl<'a, S: AsyncSeek + ?Sized + Unpin> Seek<'a, S> { + pub(super) fn new(seek: &'a mut S, pos: SeekFrom) -> Self { + Self { seek, pos } + } +} + +impl<S: AsyncSeek + ?Sized + Unpin> Future for Seek<'_, S> { + type Output = io::Result<u64>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + Pin::new(&mut this.seek).poll_seek(cx, this.pos) + } +} diff --git a/third_party/rust/futures-util/src/io/sink.rs b/third_party/rust/futures-util/src/io/sink.rs new file mode 100644 index 0000000000..4a32ca7041 --- /dev/null +++ b/third_party/rust/futures-util/src/io/sink.rs @@ -0,0 +1,67 @@ +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncWrite, IoSlice}; +use std::fmt; +use std::io; +use std::pin::Pin; + +/// Writer for the [`sink()`] function. +#[must_use = "writers do nothing unless polled"] +pub struct Sink { + _priv: (), +} + +/// Creates an instance of a writer which will successfully consume all data. +/// +/// All calls to `poll_write` on the returned instance will return `Poll::Ready(Ok(buf.len()))` +/// and the contents of the buffer will not be inspected. +/// +/// # Examples +/// +/// ```rust +/// # futures::executor::block_on(async { +/// use futures::io::{self, AsyncWriteExt}; +/// +/// let buffer = vec![1, 2, 3, 5, 8]; +/// let mut writer = io::sink(); +/// let num_bytes = writer.write(&buffer).await?; +/// assert_eq!(num_bytes, 5); +/// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); +/// ``` +pub fn sink() -> Sink { + Sink { _priv: () } +} + +impl AsyncWrite for Sink { + #[inline] + fn poll_write( + self: Pin<&mut Self>, + _: &mut Context<'_>, + buf: &[u8], + ) -> Poll<io::Result<usize>> { + Poll::Ready(Ok(buf.len())) + } + + #[inline] + fn poll_write_vectored( + self: Pin<&mut Self>, + _: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<io::Result<usize>> { + Poll::Ready(Ok(bufs.iter().map(|b| b.len()).sum())) + } + + #[inline] + fn poll_flush(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> { + Poll::Ready(Ok(())) + } + #[inline] + fn poll_close(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> { + Poll::Ready(Ok(())) + } +} + +impl fmt::Debug for Sink { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.pad("Sink { .. }") + } +} diff --git a/third_party/rust/futures-util/src/io/split.rs b/third_party/rust/futures-util/src/io/split.rs new file mode 100644 index 0000000000..3f1b9af456 --- /dev/null +++ b/third_party/rust/futures-util/src/io/split.rs @@ -0,0 +1,115 @@ +use crate::lock::BiLock; +use core::fmt; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncRead, AsyncWrite, IoSlice, IoSliceMut}; +use std::io; +use std::pin::Pin; + +/// The readable half of an object returned from `AsyncRead::split`. +#[derive(Debug)] +pub struct ReadHalf<T> { + handle: BiLock<T>, +} + +/// The writable half of an object returned from `AsyncRead::split`. +#[derive(Debug)] +pub struct WriteHalf<T> { + handle: BiLock<T>, +} + +fn lock_and_then<T, U, E, F>(lock: &BiLock<T>, cx: &mut Context<'_>, f: F) -> Poll<Result<U, E>> +where + F: FnOnce(Pin<&mut T>, &mut Context<'_>) -> Poll<Result<U, E>>, +{ + let mut l = ready!(lock.poll_lock(cx)); + f(l.as_pin_mut(), cx) +} + +pub(super) fn split<T: AsyncRead + AsyncWrite>(t: T) -> (ReadHalf<T>, WriteHalf<T>) { + let (a, b) = BiLock::new(t); + (ReadHalf { handle: a }, WriteHalf { handle: b }) +} + +impl<T: Unpin> ReadHalf<T> { + /// Attempts to put the two "halves" of a split `AsyncRead + AsyncWrite` back + /// together. Succeeds only if the `ReadHalf<T>` and `WriteHalf<T>` are + /// a matching pair originating from the same call to `AsyncReadExt::split`. + pub fn reunite(self, other: WriteHalf<T>) -> Result<T, ReuniteError<T>> { + self.handle + .reunite(other.handle) + .map_err(|err| ReuniteError(ReadHalf { handle: err.0 }, WriteHalf { handle: err.1 })) + } +} + +impl<T: Unpin> WriteHalf<T> { + /// Attempts to put the two "halves" of a split `AsyncRead + AsyncWrite` back + /// together. Succeeds only if the `ReadHalf<T>` and `WriteHalf<T>` are + /// a matching pair originating from the same call to `AsyncReadExt::split`. + pub fn reunite(self, other: ReadHalf<T>) -> Result<T, ReuniteError<T>> { + other.reunite(self) + } +} + +impl<R: AsyncRead> AsyncRead for ReadHalf<R> { + fn poll_read( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &mut [u8], + ) -> Poll<io::Result<usize>> { + lock_and_then(&self.handle, cx, |l, cx| l.poll_read(cx, buf)) + } + + fn poll_read_vectored( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &mut [IoSliceMut<'_>], + ) -> Poll<io::Result<usize>> { + lock_and_then(&self.handle, cx, |l, cx| l.poll_read_vectored(cx, bufs)) + } +} + +impl<W: AsyncWrite> AsyncWrite for WriteHalf<W> { + fn poll_write( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &[u8], + ) -> Poll<io::Result<usize>> { + lock_and_then(&self.handle, cx, |l, cx| l.poll_write(cx, buf)) + } + + fn poll_write_vectored( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<io::Result<usize>> { + lock_and_then(&self.handle, cx, |l, cx| l.poll_write_vectored(cx, bufs)) + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + lock_and_then(&self.handle, cx, |l, cx| l.poll_flush(cx)) + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + lock_and_then(&self.handle, cx, |l, cx| l.poll_close(cx)) + } +} + +/// Error indicating a `ReadHalf<T>` and `WriteHalf<T>` were not two halves +/// of a `AsyncRead + AsyncWrite`, and thus could not be `reunite`d. +pub struct ReuniteError<T>(pub ReadHalf<T>, pub WriteHalf<T>); + +impl<T> fmt::Debug for ReuniteError<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple("ReuniteError").field(&"...").finish() + } +} + +impl<T> fmt::Display for ReuniteError<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "tried to reunite a ReadHalf and WriteHalf that don't form a pair") + } +} + +#[cfg(feature = "std")] +impl<T: core::any::Any> std::error::Error for ReuniteError<T> {} diff --git a/third_party/rust/futures-util/src/io/take.rs b/third_party/rust/futures-util/src/io/take.rs new file mode 100644 index 0000000000..2c494804d9 --- /dev/null +++ b/third_party/rust/futures-util/src/io/take.rs @@ -0,0 +1,125 @@ +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncBufRead, AsyncRead}; +use pin_project_lite::pin_project; +use std::pin::Pin; +use std::{cmp, io}; + +pin_project! { + /// Reader for the [`take`](super::AsyncReadExt::take) method. + #[derive(Debug)] + #[must_use = "readers do nothing unless you `.await` or poll them"] + pub struct Take<R> { + #[pin] + inner: R, + limit: u64, + } +} + +impl<R: AsyncRead> Take<R> { + pub(super) fn new(inner: R, limit: u64) -> Self { + Self { inner, limit } + } + + /// Returns the remaining number of bytes that can be + /// read before this instance will return EOF. + /// + /// # Note + /// + /// This instance may reach `EOF` after reading fewer bytes than indicated by + /// this method if the underlying [`AsyncRead`] instance reaches EOF. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncReadExt, Cursor}; + /// + /// let reader = Cursor::new(&b"12345678"[..]); + /// let mut buffer = [0; 2]; + /// + /// let mut take = reader.take(4); + /// let n = take.read(&mut buffer).await?; + /// + /// assert_eq!(take.limit(), 2); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + pub fn limit(&self) -> u64 { + self.limit + } + + /// Sets the number of bytes that can be read before this instance will + /// return EOF. This is the same as constructing a new `Take` instance, so + /// the amount of bytes read and the previous limit value don't matter when + /// calling this method. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::io::{AsyncReadExt, Cursor}; + /// + /// let reader = Cursor::new(&b"12345678"[..]); + /// let mut buffer = [0; 4]; + /// + /// let mut take = reader.take(4); + /// let n = take.read(&mut buffer).await?; + /// + /// assert_eq!(n, 4); + /// assert_eq!(take.limit(), 0); + /// + /// take.set_limit(10); + /// let n = take.read(&mut buffer).await?; + /// assert_eq!(n, 4); + /// + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + pub fn set_limit(&mut self, limit: u64) { + self.limit = limit + } + + delegate_access_inner!(inner, R, ()); +} + +impl<R: AsyncRead> AsyncRead for Take<R> { + fn poll_read( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &mut [u8], + ) -> Poll<Result<usize, io::Error>> { + let this = self.project(); + + if *this.limit == 0 { + return Poll::Ready(Ok(0)); + } + + let max = cmp::min(buf.len() as u64, *this.limit) as usize; + let n = ready!(this.inner.poll_read(cx, &mut buf[..max]))?; + *this.limit -= n as u64; + Poll::Ready(Ok(n)) + } +} + +impl<R: AsyncBufRead> AsyncBufRead for Take<R> { + fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> { + let this = self.project(); + + // Don't call into inner reader at all at EOF because it may still block + if *this.limit == 0 { + return Poll::Ready(Ok(&[])); + } + + let buf = ready!(this.inner.poll_fill_buf(cx)?); + let cap = cmp::min(buf.len() as u64, *this.limit) as usize; + Poll::Ready(Ok(&buf[..cap])) + } + + fn consume(self: Pin<&mut Self>, amt: usize) { + let this = self.project(); + + // Don't let callers reset the limit by passing an overlarge value + let amt = cmp::min(amt as u64, *this.limit) as usize; + *this.limit -= amt as u64; + this.inner.consume(amt); + } +} diff --git a/third_party/rust/futures-util/src/io/window.rs b/third_party/rust/futures-util/src/io/window.rs new file mode 100644 index 0000000000..77b7267c69 --- /dev/null +++ b/third_party/rust/futures-util/src/io/window.rs @@ -0,0 +1,104 @@ +use std::ops::{Bound, Range, RangeBounds}; + +/// A owned window around an underlying buffer. +/// +/// Normally slices work great for considering sub-portions of a buffer, but +/// unfortunately a slice is a *borrowed* type in Rust which has an associated +/// lifetime. When working with future and async I/O these lifetimes are not +/// always appropriate, and are sometimes difficult to store in tasks. This +/// type strives to fill this gap by providing an "owned slice" around an +/// underlying buffer of bytes. +/// +/// A `Window<T>` wraps an underlying buffer, `T`, and has configurable +/// start/end indexes to alter the behavior of the `AsRef<[u8]>` implementation +/// that this type carries. +/// +/// This type can be particularly useful when working with the `write_all` +/// combinator in this crate. Data can be sliced via `Window`, consumed by +/// `write_all`, and then earned back once the write operation finishes through +/// the `into_inner` method on this type. +#[derive(Debug)] +pub struct Window<T> { + inner: T, + range: Range<usize>, +} + +impl<T: AsRef<[u8]>> Window<T> { + /// Creates a new window around the buffer `t` defaulting to the entire + /// slice. + /// + /// Further methods can be called on the returned `Window<T>` to alter the + /// window into the data provided. + pub fn new(t: T) -> Self { + Self { range: 0..t.as_ref().len(), inner: t } + } + + /// Gets a shared reference to the underlying buffer inside of this + /// `Window`. + pub fn get_ref(&self) -> &T { + &self.inner + } + + /// Gets a mutable reference to the underlying buffer inside of this + /// `Window`. + pub fn get_mut(&mut self) -> &mut T { + &mut self.inner + } + + /// Consumes this `Window`, returning the underlying buffer. + pub fn into_inner(self) -> T { + self.inner + } + + /// Returns the starting index of this window into the underlying buffer + /// `T`. + pub fn start(&self) -> usize { + self.range.start + } + + /// Returns the end index of this window into the underlying buffer + /// `T`. + pub fn end(&self) -> usize { + self.range.end + } + + /// Changes the range of this window to the range specified. + /// + /// # Panics + /// + /// This method will panic if `range` is out of bounds for the underlying + /// slice or if [`start_bound()`] of `range` comes after the [`end_bound()`]. + /// + /// [`start_bound()`]: std::ops::RangeBounds::start_bound + /// [`end_bound()`]: std::ops::RangeBounds::end_bound + pub fn set<R: RangeBounds<usize>>(&mut self, range: R) { + let start = match range.start_bound() { + Bound::Included(n) => *n, + Bound::Excluded(n) => *n + 1, + Bound::Unbounded => 0, + }; + let end = match range.end_bound() { + Bound::Included(n) => *n + 1, + Bound::Excluded(n) => *n, + Bound::Unbounded => self.inner.as_ref().len(), + }; + + assert!(end <= self.inner.as_ref().len()); + assert!(start <= end); + + self.range.start = start; + self.range.end = end; + } +} + +impl<T: AsRef<[u8]>> AsRef<[u8]> for Window<T> { + fn as_ref(&self) -> &[u8] { + &self.inner.as_ref()[self.range.start..self.range.end] + } +} + +impl<T: AsMut<[u8]>> AsMut<[u8]> for Window<T> { + fn as_mut(&mut self) -> &mut [u8] { + &mut self.inner.as_mut()[self.range.start..self.range.end] + } +} diff --git a/third_party/rust/futures-util/src/io/write.rs b/third_party/rust/futures-util/src/io/write.rs new file mode 100644 index 0000000000..c47ef9e2eb --- /dev/null +++ b/third_party/rust/futures-util/src/io/write.rs @@ -0,0 +1,30 @@ +use crate::io::AsyncWrite; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use std::io; +use std::pin::Pin; + +/// Future for the [`write`](super::AsyncWriteExt::write) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Write<'a, W: ?Sized> { + writer: &'a mut W, + buf: &'a [u8], +} + +impl<W: ?Sized + Unpin> Unpin for Write<'_, W> {} + +impl<'a, W: AsyncWrite + ?Sized + Unpin> Write<'a, W> { + pub(super) fn new(writer: &'a mut W, buf: &'a [u8]) -> Self { + Self { writer, buf } + } +} + +impl<W: AsyncWrite + ?Sized + Unpin> Future for Write<'_, W> { + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + Pin::new(&mut this.writer).poll_write(cx, this.buf) + } +} diff --git a/third_party/rust/futures-util/src/io/write_all.rs b/third_party/rust/futures-util/src/io/write_all.rs new file mode 100644 index 0000000000..08c025f94d --- /dev/null +++ b/third_party/rust/futures-util/src/io/write_all.rs @@ -0,0 +1,43 @@ +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncWrite; +use std::io; +use std::mem; +use std::pin::Pin; + +/// Future for the [`write_all`](super::AsyncWriteExt::write_all) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct WriteAll<'a, W: ?Sized> { + writer: &'a mut W, + buf: &'a [u8], +} + +impl<W: ?Sized + Unpin> Unpin for WriteAll<'_, W> {} + +impl<'a, W: AsyncWrite + ?Sized + Unpin> WriteAll<'a, W> { + pub(super) fn new(writer: &'a mut W, buf: &'a [u8]) -> Self { + Self { writer, buf } + } +} + +impl<W: AsyncWrite + ?Sized + Unpin> Future for WriteAll<'_, W> { + type Output = io::Result<()>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + let this = &mut *self; + while !this.buf.is_empty() { + let n = ready!(Pin::new(&mut this.writer).poll_write(cx, this.buf))?; + { + let (_, rest) = mem::take(&mut this.buf).split_at(n); + this.buf = rest; + } + if n == 0 { + return Poll::Ready(Err(io::ErrorKind::WriteZero.into())); + } + } + + Poll::Ready(Ok(())) + } +} diff --git a/third_party/rust/futures-util/src/io/write_all_vectored.rs b/third_party/rust/futures-util/src/io/write_all_vectored.rs new file mode 100644 index 0000000000..a8fc4c641c --- /dev/null +++ b/third_party/rust/futures-util/src/io/write_all_vectored.rs @@ -0,0 +1,193 @@ +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncWrite; +use futures_io::IoSlice; +use std::io; +use std::pin::Pin; + +/// Future for the +/// [`write_all_vectored`](super::AsyncWriteExt::write_all_vectored) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct WriteAllVectored<'a, W: ?Sized + Unpin> { + writer: &'a mut W, + bufs: &'a mut [IoSlice<'a>], +} + +impl<W: ?Sized + Unpin> Unpin for WriteAllVectored<'_, W> {} + +impl<'a, W: AsyncWrite + ?Sized + Unpin> WriteAllVectored<'a, W> { + pub(super) fn new(writer: &'a mut W, mut bufs: &'a mut [IoSlice<'a>]) -> Self { + IoSlice::advance_slices(&mut bufs, 0); + Self { writer, bufs } + } +} + +impl<W: AsyncWrite + ?Sized + Unpin> Future for WriteAllVectored<'_, W> { + type Output = io::Result<()>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> { + let this = &mut *self; + while !this.bufs.is_empty() { + let n = ready!(Pin::new(&mut this.writer).poll_write_vectored(cx, this.bufs))?; + if n == 0 { + return Poll::Ready(Err(io::ErrorKind::WriteZero.into())); + } else { + IoSlice::advance_slices(&mut this.bufs, n); + } + } + + Poll::Ready(Ok(())) + } +} + +#[cfg(test)] +mod tests { + use std::cmp::min; + use std::future::Future; + use std::io; + use std::pin::Pin; + use std::task::{Context, Poll}; + + use crate::io::{AsyncWrite, AsyncWriteExt, IoSlice}; + use crate::task::noop_waker; + + /// Create a new writer that reads from at most `n_bufs` and reads + /// `per_call` bytes (in total) per call to write. + fn test_writer(n_bufs: usize, per_call: usize) -> TestWriter { + TestWriter { n_bufs, per_call, written: Vec::new() } + } + + // TODO: maybe move this the future-test crate? + struct TestWriter { + n_bufs: usize, + per_call: usize, + written: Vec<u8>, + } + + impl AsyncWrite for TestWriter { + fn poll_write( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &[u8], + ) -> Poll<io::Result<usize>> { + self.poll_write_vectored(cx, &[IoSlice::new(buf)]) + } + + fn poll_write_vectored( + mut self: Pin<&mut Self>, + _cx: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<io::Result<usize>> { + let mut left = self.per_call; + let mut written = 0; + for buf in bufs.iter().take(self.n_bufs) { + let n = min(left, buf.len()); + self.written.extend_from_slice(&buf[0..n]); + left -= n; + written += n; + } + Poll::Ready(Ok(written)) + } + + fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> { + Poll::Ready(Ok(())) + } + + fn poll_close(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> { + Poll::Ready(Ok(())) + } + } + + // TODO: maybe move this the future-test crate? + macro_rules! assert_poll_ok { + ($e:expr, $expected:expr) => { + let expected = $expected; + match $e { + Poll::Ready(Ok(ok)) if ok == expected => {} + got => { + panic!("unexpected result, got: {:?}, wanted: Ready(Ok({:?}))", got, expected) + } + } + }; + } + + #[test] + fn test_writer_read_from_one_buf() { + let waker = noop_waker(); + let mut cx = Context::from_waker(&waker); + + let mut dst = test_writer(1, 2); + let mut dst = Pin::new(&mut dst); + + assert_poll_ok!(dst.as_mut().poll_write(&mut cx, &[]), 0); + assert_poll_ok!(dst.as_mut().poll_write_vectored(&mut cx, &[]), 0); + + // Read at most 2 bytes. + assert_poll_ok!(dst.as_mut().poll_write(&mut cx, &[1, 1, 1]), 2); + let bufs = &[IoSlice::new(&[2, 2, 2])]; + assert_poll_ok!(dst.as_mut().poll_write_vectored(&mut cx, bufs), 2); + + // Only read from first buf. + let bufs = &[IoSlice::new(&[3]), IoSlice::new(&[4, 4])]; + assert_poll_ok!(dst.as_mut().poll_write_vectored(&mut cx, bufs), 1); + + assert_eq!(dst.written, &[1, 1, 2, 2, 3]); + } + + #[test] + fn test_writer_read_from_multiple_bufs() { + let waker = noop_waker(); + let mut cx = Context::from_waker(&waker); + + let mut dst = test_writer(3, 3); + let mut dst = Pin::new(&mut dst); + + // Read at most 3 bytes from two buffers. + let bufs = &[IoSlice::new(&[1]), IoSlice::new(&[2, 2, 2])]; + assert_poll_ok!(dst.as_mut().poll_write_vectored(&mut cx, bufs), 3); + + // Read at most 3 bytes from three buffers. + let bufs = &[IoSlice::new(&[3]), IoSlice::new(&[4]), IoSlice::new(&[5, 5])]; + assert_poll_ok!(dst.as_mut().poll_write_vectored(&mut cx, bufs), 3); + + assert_eq!(dst.written, &[1, 2, 2, 3, 4, 5]); + } + + #[test] + fn test_write_all_vectored() { + let waker = noop_waker(); + let mut cx = Context::from_waker(&waker); + + #[rustfmt::skip] // Becomes unreadable otherwise. + let tests: Vec<(_, &'static [u8])> = vec![ + (vec![], &[]), + (vec![IoSlice::new(&[]), IoSlice::new(&[])], &[]), + (vec![IoSlice::new(&[1])], &[1]), + (vec![IoSlice::new(&[1, 2])], &[1, 2]), + (vec![IoSlice::new(&[1, 2, 3])], &[1, 2, 3]), + (vec![IoSlice::new(&[1, 2, 3, 4])], &[1, 2, 3, 4]), + (vec![IoSlice::new(&[1, 2, 3, 4, 5])], &[1, 2, 3, 4, 5]), + (vec![IoSlice::new(&[1]), IoSlice::new(&[2])], &[1, 2]), + (vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2])], &[1, 1, 2, 2]), + (vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 1, 2, 2, 2]), + (vec![IoSlice::new(&[1, 1, 1, 1]), IoSlice::new(&[2, 2, 2, 2])], &[1, 1, 1, 1, 2, 2, 2, 2]), + (vec![IoSlice::new(&[1]), IoSlice::new(&[2]), IoSlice::new(&[3])], &[1, 2, 3]), + (vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2]), IoSlice::new(&[3, 3])], &[1, 1, 2, 2, 3, 3]), + (vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2]), IoSlice::new(&[3, 3, 3])], &[1, 1, 1, 2, 2, 2, 3, 3, 3]), + ]; + + for (mut input, wanted) in tests { + let mut dst = test_writer(2, 2); + { + let mut future = dst.write_all_vectored(&mut *input); + match Pin::new(&mut future).poll(&mut cx) { + Poll::Ready(Ok(())) => {} + other => panic!("unexpected result polling future: {:?}", other), + } + } + assert_eq!(&*dst.written, &*wanted); + } + } +} diff --git a/third_party/rust/futures-util/src/io/write_vectored.rs b/third_party/rust/futures-util/src/io/write_vectored.rs new file mode 100644 index 0000000000..14a01d7302 --- /dev/null +++ b/third_party/rust/futures-util/src/io/write_vectored.rs @@ -0,0 +1,30 @@ +use crate::io::AsyncWrite; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use std::io::{self, IoSlice}; +use std::pin::Pin; + +/// Future for the [`write_vectored`](super::AsyncWriteExt::write_vectored) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct WriteVectored<'a, W: ?Sized> { + writer: &'a mut W, + bufs: &'a [IoSlice<'a>], +} + +impl<W: ?Sized + Unpin> Unpin for WriteVectored<'_, W> {} + +impl<'a, W: AsyncWrite + ?Sized + Unpin> WriteVectored<'a, W> { + pub(super) fn new(writer: &'a mut W, bufs: &'a [IoSlice<'a>]) -> Self { + Self { writer, bufs } + } +} + +impl<W: AsyncWrite + ?Sized + Unpin> Future for WriteVectored<'_, W> { + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + Pin::new(&mut this.writer).poll_write_vectored(cx, this.bufs) + } +} diff --git a/third_party/rust/futures-util/src/lib.rs b/third_party/rust/futures-util/src/lib.rs new file mode 100644 index 0000000000..9a10c93c9a --- /dev/null +++ b/third_party/rust/futures-util/src/lib.rs @@ -0,0 +1,337 @@ +//! Combinators and utilities for working with `Future`s, `Stream`s, `Sink`s, +//! and the `AsyncRead` and `AsyncWrite` traits. + +#![cfg_attr(feature = "write-all-vectored", feature(io_slice_advance))] +#![cfg_attr(not(feature = "std"), no_std)] +#![warn( + missing_debug_implementations, + missing_docs, + rust_2018_idioms, + single_use_lifetimes, + unreachable_pub +)] +#![doc(test( + no_crate_inject, + attr( + deny(warnings, rust_2018_idioms, single_use_lifetimes), + allow(dead_code, unused_assignments, unused_variables) + ) +))] +#![cfg_attr(docsrs, feature(doc_cfg))] + +#[cfg(all(feature = "bilock", not(feature = "unstable")))] +compile_error!("The `bilock` feature requires the `unstable` feature as an explicit opt-in to unstable features"); + +#[cfg(feature = "alloc")] +extern crate alloc; + +// Macro re-exports +pub use futures_core::ready; +pub use pin_utils::pin_mut; + +#[cfg(feature = "async-await")] +#[macro_use] +mod async_await; +#[cfg(feature = "async-await")] +#[doc(hidden)] +pub use self::async_await::*; + +// Not public API. +#[cfg(feature = "async-await")] +#[doc(hidden)] +pub mod __private { + pub use crate::*; + pub use core::{ + option::Option::{self, None, Some}, + pin::Pin, + result::Result::{Err, Ok}, + }; + + pub mod async_await { + pub use crate::async_await::*; + } +} + +#[cfg(feature = "sink")] +macro_rules! delegate_sink { + ($field:ident, $item:ty) => { + fn poll_ready( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + ) -> core::task::Poll<Result<(), Self::Error>> { + self.project().$field.poll_ready(cx) + } + + fn start_send(self: core::pin::Pin<&mut Self>, item: $item) -> Result<(), Self::Error> { + self.project().$field.start_send(item) + } + + fn poll_flush( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + ) -> core::task::Poll<Result<(), Self::Error>> { + self.project().$field.poll_flush(cx) + } + + fn poll_close( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + ) -> core::task::Poll<Result<(), Self::Error>> { + self.project().$field.poll_close(cx) + } + }; +} + +macro_rules! delegate_future { + ($field:ident) => { + fn poll( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + ) -> core::task::Poll<Self::Output> { + self.project().$field.poll(cx) + } + }; +} + +macro_rules! delegate_stream { + ($field:ident) => { + fn poll_next( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + ) -> core::task::Poll<Option<Self::Item>> { + self.project().$field.poll_next(cx) + } + fn size_hint(&self) -> (usize, Option<usize>) { + self.$field.size_hint() + } + }; +} + +#[cfg(feature = "io")] +#[cfg(feature = "std")] +macro_rules! delegate_async_write { + ($field:ident) => { + fn poll_write( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + buf: &[u8], + ) -> core::task::Poll<std::io::Result<usize>> { + self.project().$field.poll_write(cx, buf) + } + fn poll_write_vectored( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + bufs: &[std::io::IoSlice<'_>], + ) -> core::task::Poll<std::io::Result<usize>> { + self.project().$field.poll_write_vectored(cx, bufs) + } + fn poll_flush( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + ) -> core::task::Poll<std::io::Result<()>> { + self.project().$field.poll_flush(cx) + } + fn poll_close( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + ) -> core::task::Poll<std::io::Result<()>> { + self.project().$field.poll_close(cx) + } + }; +} + +#[cfg(feature = "io")] +#[cfg(feature = "std")] +macro_rules! delegate_async_read { + ($field:ident) => { + fn poll_read( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + buf: &mut [u8], + ) -> core::task::Poll<std::io::Result<usize>> { + self.project().$field.poll_read(cx, buf) + } + + fn poll_read_vectored( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + bufs: &mut [std::io::IoSliceMut<'_>], + ) -> core::task::Poll<std::io::Result<usize>> { + self.project().$field.poll_read_vectored(cx, bufs) + } + }; +} + +#[cfg(feature = "io")] +#[cfg(feature = "std")] +macro_rules! delegate_async_buf_read { + ($field:ident) => { + fn poll_fill_buf( + self: core::pin::Pin<&mut Self>, + cx: &mut core::task::Context<'_>, + ) -> core::task::Poll<std::io::Result<&[u8]>> { + self.project().$field.poll_fill_buf(cx) + } + + fn consume(self: core::pin::Pin<&mut Self>, amt: usize) { + self.project().$field.consume(amt) + } + }; +} + +macro_rules! delegate_access_inner { + ($field:ident, $inner:ty, ($($ind:tt)*)) => { + /// Acquires a reference to the underlying sink or stream that this combinator is + /// pulling from. + pub fn get_ref(&self) -> &$inner { + (&self.$field) $($ind get_ref())* + } + + /// Acquires a mutable reference to the underlying sink or stream that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// sink or stream which may otherwise confuse this combinator. + pub fn get_mut(&mut self) -> &mut $inner { + (&mut self.$field) $($ind get_mut())* + } + + /// Acquires a pinned mutable reference to the underlying sink or stream that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// sink or stream which may otherwise confuse this combinator. + pub fn get_pin_mut(self: core::pin::Pin<&mut Self>) -> core::pin::Pin<&mut $inner> { + self.project().$field $($ind get_pin_mut())* + } + + /// Consumes this combinator, returning the underlying sink or stream. + /// + /// Note that this may discard intermediate state of this combinator, so + /// care should be taken to avoid losing resources when this is called. + pub fn into_inner(self) -> $inner { + self.$field $($ind into_inner())* + } + } +} + +macro_rules! delegate_all { + (@trait Future $name:ident < $($arg:ident),* > ($t:ty) $(where $($bound:tt)*)*) => { + impl<$($arg),*> futures_core::future::Future for $name<$($arg),*> where $t: futures_core::future::Future $(, $($bound)*)* { + type Output = <$t as futures_core::future::Future>::Output; + + delegate_future!(inner); + } + }; + (@trait FusedFuture $name:ident < $($arg:ident),* > ($t:ty) $(where $($bound:tt)*)*) => { + impl<$($arg),*> futures_core::future::FusedFuture for $name<$($arg),*> where $t: futures_core::future::FusedFuture $(, $($bound)*)* { + fn is_terminated(&self) -> bool { + self.inner.is_terminated() + } + } + }; + (@trait Stream $name:ident < $($arg:ident),* > ($t:ty) $(where $($bound:tt)*)*) => { + impl<$($arg),*> futures_core::stream::Stream for $name<$($arg),*> where $t: futures_core::stream::Stream $(, $($bound)*)* { + type Item = <$t as futures_core::stream::Stream>::Item; + + delegate_stream!(inner); + } + }; + (@trait FusedStream $name:ident < $($arg:ident),* > ($t:ty) $(where $($bound:tt)*)*) => { + impl<$($arg),*> futures_core::stream::FusedStream for $name<$($arg),*> where $t: futures_core::stream::FusedStream $(, $($bound)*)* { + fn is_terminated(&self) -> bool { + self.inner.is_terminated() + } + } + }; + (@trait Sink $name:ident < $($arg:ident),* > ($t:ty) $(where $($bound:tt)*)*) => { + #[cfg(feature = "sink")] + impl<_Item, $($arg),*> futures_sink::Sink<_Item> for $name<$($arg),*> where $t: futures_sink::Sink<_Item> $(, $($bound)*)* { + type Error = <$t as futures_sink::Sink<_Item>>::Error; + + delegate_sink!(inner, _Item); + } + }; + (@trait Debug $name:ident < $($arg:ident),* > ($t:ty) $(where $($bound:tt)*)*) => { + impl<$($arg),*> core::fmt::Debug for $name<$($arg),*> where $t: core::fmt::Debug $(, $($bound)*)* { + fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result { + core::fmt::Debug::fmt(&self.inner, f) + } + } + }; + (@trait AccessInner[$inner:ty, ($($ind:tt)*)] $name:ident < $($arg:ident),* > ($t:ty) $(where $($bound:tt)*)*) => { + impl<$($arg),*> $name<$($arg),*> $(where $($bound)*)* { + delegate_access_inner!(inner, $inner, ($($ind)*)); + } + }; + (@trait New[|$($param:ident: $paramt:ty),*| $cons:expr] $name:ident < $($arg:ident),* > ($t:ty) $(where $($bound:tt)*)*) => { + impl<$($arg),*> $name<$($arg),*> $(where $($bound)*)* { + pub(crate) fn new($($param: $paramt),*) -> Self { + Self { inner: $cons } + } + } + }; + ($(#[$attr:meta])* $name:ident<$($arg:ident),*>($t:ty) : $ftrait:ident $([$($targs:tt)*])* $({$($item:tt)*})* $(where $($bound:tt)*)*) => { + pin_project_lite::pin_project! { + #[must_use = "futures/streams/sinks do nothing unless you `.await` or poll them"] + $(#[$attr])* + pub struct $name< $($arg),* > $(where $($bound)*)* { #[pin] inner: $t } + } + + impl<$($arg),*> $name< $($arg),* > $(where $($bound)*)* { + $($($item)*)* + } + + delegate_all!(@trait $ftrait $([$($targs)*])* $name<$($arg),*>($t) $(where $($bound)*)*); + }; + ($(#[$attr:meta])* $name:ident<$($arg:ident),*>($t:ty) : $ftrait:ident $([$($ftargs:tt)*])* + $strait:ident $([$($stargs:tt)*])* $(+ $trait:ident $([$($targs:tt)*])*)* $({$($item:tt)*})* $(where $($bound:tt)*)*) => { + delegate_all!($(#[$attr])* $name<$($arg),*>($t) : $strait $([$($stargs)*])* $(+ $trait $([$($targs)*])*)* $({$($item)*})* $(where $($bound)*)*); + + delegate_all!(@trait $ftrait $([$($ftargs)*])* $name<$($arg),*>($t) $(where $($bound)*)*); + }; +} + +pub mod future; +#[doc(no_inline)] +pub use crate::future::{Future, FutureExt, TryFuture, TryFutureExt}; + +pub mod stream; +#[doc(no_inline)] +pub use crate::stream::{Stream, StreamExt, TryStream, TryStreamExt}; + +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub mod sink; +#[cfg(feature = "sink")] +#[doc(no_inline)] +pub use crate::sink::{Sink, SinkExt}; + +pub mod task; + +pub mod never; + +#[cfg(feature = "compat")] +#[cfg_attr(docsrs, doc(cfg(feature = "compat")))] +pub mod compat; + +#[cfg(feature = "io")] +#[cfg_attr(docsrs, doc(cfg(feature = "io")))] +#[cfg(feature = "std")] +pub mod io; +#[cfg(feature = "io")] +#[cfg(feature = "std")] +#[doc(no_inline)] +pub use crate::io::{ + AsyncBufRead, AsyncBufReadExt, AsyncRead, AsyncReadExt, AsyncSeek, AsyncSeekExt, AsyncWrite, + AsyncWriteExt, +}; + +#[cfg(feature = "alloc")] +pub mod lock; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod abortable; + +mod fns; +mod unfold_state; diff --git a/third_party/rust/futures-util/src/lock/bilock.rs b/third_party/rust/futures-util/src/lock/bilock.rs new file mode 100644 index 0000000000..2174079c83 --- /dev/null +++ b/third_party/rust/futures-util/src/lock/bilock.rs @@ -0,0 +1,279 @@ +//! Futures-powered synchronization primitives. + +use alloc::boxed::Box; +use alloc::sync::Arc; +use core::cell::UnsafeCell; +use core::fmt; +use core::ops::{Deref, DerefMut}; +use core::pin::Pin; +use core::sync::atomic::AtomicUsize; +use core::sync::atomic::Ordering::SeqCst; +#[cfg(feature = "bilock")] +use futures_core::future::Future; +use futures_core::task::{Context, Poll, Waker}; + +/// A type of futures-powered synchronization primitive which is a mutex between +/// two possible owners. +/// +/// This primitive is not as generic as a full-blown mutex but is sufficient for +/// many use cases where there are only two possible owners of a resource. The +/// implementation of `BiLock` can be more optimized for just the two possible +/// owners. +/// +/// Note that it's possible to use this lock through a poll-style interface with +/// the `poll_lock` method but you can also use it as a future with the `lock` +/// method that consumes a `BiLock` and returns a future that will resolve when +/// it's locked. +/// +/// A `BiLock` is typically used for "split" operations where data which serves +/// two purposes wants to be split into two to be worked with separately. For +/// example a TCP stream could be both a reader and a writer or a framing layer +/// could be both a stream and a sink for messages. A `BiLock` enables splitting +/// these two and then using each independently in a futures-powered fashion. +/// +/// This type is only available when the `bilock` feature of this +/// library is activated. +#[derive(Debug)] +#[cfg_attr(docsrs, doc(cfg(feature = "bilock")))] +pub struct BiLock<T> { + arc: Arc<Inner<T>>, +} + +#[derive(Debug)] +struct Inner<T> { + state: AtomicUsize, + value: Option<UnsafeCell<T>>, +} + +unsafe impl<T: Send> Send for Inner<T> {} +unsafe impl<T: Send> Sync for Inner<T> {} + +impl<T> BiLock<T> { + /// Creates a new `BiLock` protecting the provided data. + /// + /// Two handles to the lock are returned, and these are the only two handles + /// that will ever be available to the lock. These can then be sent to separate + /// tasks to be managed there. + /// + /// The data behind the bilock is considered to be pinned, which allows `Pin` + /// references to locked data. However, this means that the locked value + /// will only be available through `Pin<&mut T>` (not `&mut T`) unless `T` is `Unpin`. + /// Similarly, reuniting the lock and extracting the inner value is only + /// possible when `T` is `Unpin`. + pub fn new(t: T) -> (Self, Self) { + let arc = Arc::new(Inner { state: AtomicUsize::new(0), value: Some(UnsafeCell::new(t)) }); + + (Self { arc: arc.clone() }, Self { arc }) + } + + /// Attempt to acquire this lock, returning `Pending` if it can't be + /// acquired. + /// + /// This function will acquire the lock in a nonblocking fashion, returning + /// immediately if the lock is already held. If the lock is successfully + /// acquired then `Poll::Ready` is returned with a value that represents + /// the locked value (and can be used to access the protected data). The + /// lock is unlocked when the returned `BiLockGuard` is dropped. + /// + /// If the lock is already held then this function will return + /// `Poll::Pending`. In this case the current task will also be scheduled + /// to receive a notification when the lock would otherwise become + /// available. + /// + /// # Panics + /// + /// This function will panic if called outside the context of a future's + /// task. + pub fn poll_lock(&self, cx: &mut Context<'_>) -> Poll<BiLockGuard<'_, T>> { + let mut waker = None; + loop { + match self.arc.state.swap(1, SeqCst) { + // Woohoo, we grabbed the lock! + 0 => return Poll::Ready(BiLockGuard { bilock: self }), + + // Oops, someone else has locked the lock + 1 => {} + + // A task was previously blocked on this lock, likely our task, + // so we need to update that task. + n => unsafe { + let mut prev = Box::from_raw(n as *mut Waker); + *prev = cx.waker().clone(); + waker = Some(prev); + }, + } + + // type ascription for safety's sake! + let me: Box<Waker> = waker.take().unwrap_or_else(|| Box::new(cx.waker().clone())); + let me = Box::into_raw(me) as usize; + + match self.arc.state.compare_exchange(1, me, SeqCst, SeqCst) { + // The lock is still locked, but we've now parked ourselves, so + // just report that we're scheduled to receive a notification. + Ok(_) => return Poll::Pending, + + // Oops, looks like the lock was unlocked after our swap above + // and before the compare_exchange. Deallocate what we just + // allocated and go through the loop again. + Err(0) => unsafe { + waker = Some(Box::from_raw(me as *mut Waker)); + }, + + // The top of this loop set the previous state to 1, so if we + // failed the CAS above then it's because the previous value was + // *not* zero or one. This indicates that a task was blocked, + // but we're trying to acquire the lock and there's only one + // other reference of the lock, so it should be impossible for + // that task to ever block itself. + Err(n) => panic!("invalid state: {}", n), + } + } + } + + /// Perform a "blocking lock" of this lock, consuming this lock handle and + /// returning a future to the acquired lock. + /// + /// This function consumes the `BiLock<T>` and returns a sentinel future, + /// `BiLockAcquire<T>`. The returned future will resolve to + /// `BiLockAcquired<T>` which represents a locked lock similarly to + /// `BiLockGuard<T>`. + /// + /// Note that the returned future will never resolve to an error. + #[cfg(feature = "bilock")] + #[cfg_attr(docsrs, doc(cfg(feature = "bilock")))] + pub fn lock(&self) -> BiLockAcquire<'_, T> { + BiLockAcquire { bilock: self } + } + + /// Attempts to put the two "halves" of a `BiLock<T>` back together and + /// recover the original value. Succeeds only if the two `BiLock<T>`s + /// originated from the same call to `BiLock::new`. + pub fn reunite(self, other: Self) -> Result<T, ReuniteError<T>> + where + T: Unpin, + { + if Arc::ptr_eq(&self.arc, &other.arc) { + drop(other); + let inner = Arc::try_unwrap(self.arc) + .ok() + .expect("futures: try_unwrap failed in BiLock<T>::reunite"); + Ok(unsafe { inner.into_value() }) + } else { + Err(ReuniteError(self, other)) + } + } + + fn unlock(&self) { + match self.arc.state.swap(0, SeqCst) { + // we've locked the lock, shouldn't be possible for us to see an + // unlocked lock. + 0 => panic!("invalid unlocked state"), + + // Ok, no one else tried to get the lock, we're done. + 1 => {} + + // Another task has parked themselves on this lock, let's wake them + // up as its now their turn. + n => unsafe { + Box::from_raw(n as *mut Waker).wake(); + }, + } + } +} + +impl<T: Unpin> Inner<T> { + unsafe fn into_value(mut self) -> T { + self.value.take().unwrap().into_inner() + } +} + +impl<T> Drop for Inner<T> { + fn drop(&mut self) { + assert_eq!(self.state.load(SeqCst), 0); + } +} + +/// Error indicating two `BiLock<T>`s were not two halves of a whole, and +/// thus could not be `reunite`d. +#[cfg_attr(docsrs, doc(cfg(feature = "bilock")))] +pub struct ReuniteError<T>(pub BiLock<T>, pub BiLock<T>); + +impl<T> fmt::Debug for ReuniteError<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple("ReuniteError").field(&"...").finish() + } +} + +impl<T> fmt::Display for ReuniteError<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "tried to reunite two BiLocks that don't form a pair") + } +} + +#[cfg(feature = "std")] +impl<T: core::any::Any> std::error::Error for ReuniteError<T> {} + +/// Returned RAII guard from the `poll_lock` method. +/// +/// This structure acts as a sentinel to the data in the `BiLock<T>` itself, +/// implementing `Deref` and `DerefMut` to `T`. When dropped, the lock will be +/// unlocked. +#[derive(Debug)] +#[cfg_attr(docsrs, doc(cfg(feature = "bilock")))] +pub struct BiLockGuard<'a, T> { + bilock: &'a BiLock<T>, +} + +// We allow parallel access to T via Deref, so Sync bound is also needed here. +unsafe impl<T: Send + Sync> Sync for BiLockGuard<'_, T> {} + +impl<T> Deref for BiLockGuard<'_, T> { + type Target = T; + fn deref(&self) -> &T { + unsafe { &*self.bilock.arc.value.as_ref().unwrap().get() } + } +} + +impl<T: Unpin> DerefMut for BiLockGuard<'_, T> { + fn deref_mut(&mut self) -> &mut T { + unsafe { &mut *self.bilock.arc.value.as_ref().unwrap().get() } + } +} + +impl<T> BiLockGuard<'_, T> { + /// Get a mutable pinned reference to the locked value. + pub fn as_pin_mut(&mut self) -> Pin<&mut T> { + // Safety: we never allow moving a !Unpin value out of a bilock, nor + // allow mutable access to it + unsafe { Pin::new_unchecked(&mut *self.bilock.arc.value.as_ref().unwrap().get()) } + } +} + +impl<T> Drop for BiLockGuard<'_, T> { + fn drop(&mut self) { + self.bilock.unlock(); + } +} + +/// Future returned by `BiLock::lock` which will resolve when the lock is +/// acquired. +#[cfg(feature = "bilock")] +#[cfg_attr(docsrs, doc(cfg(feature = "bilock")))] +#[must_use = "futures do nothing unless you `.await` or poll them"] +#[derive(Debug)] +pub struct BiLockAcquire<'a, T> { + bilock: &'a BiLock<T>, +} + +// Pinning is never projected to fields +#[cfg(feature = "bilock")] +impl<T> Unpin for BiLockAcquire<'_, T> {} + +#[cfg(feature = "bilock")] +impl<'a, T> Future for BiLockAcquire<'a, T> { + type Output = BiLockGuard<'a, T>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + self.bilock.poll_lock(cx) + } +} diff --git a/third_party/rust/futures-util/src/lock/mod.rs b/third_party/rust/futures-util/src/lock/mod.rs new file mode 100644 index 0000000000..0be72717c8 --- /dev/null +++ b/third_party/rust/futures-util/src/lock/mod.rs @@ -0,0 +1,27 @@ +//! Futures-powered synchronization primitives. +//! +//! This module is only available when the `std` or `alloc` feature of this +//! library is activated, and it is activated by default. + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(any(feature = "sink", feature = "io"))] +#[cfg(not(feature = "bilock"))] +pub(crate) use self::bilock::BiLock; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "bilock")] +#[cfg_attr(docsrs, doc(cfg(feature = "bilock")))] +pub use self::bilock::{BiLock, BiLockAcquire, BiLockGuard, ReuniteError}; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "std")] +pub use self::mutex::{ + MappedMutexGuard, Mutex, MutexGuard, MutexLockFuture, OwnedMutexGuard, OwnedMutexLockFuture, +}; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(any(feature = "bilock", feature = "sink", feature = "io"))] +#[cfg_attr(docsrs, doc(cfg(feature = "bilock")))] +#[cfg_attr(not(feature = "bilock"), allow(unreachable_pub))] +mod bilock; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "std")] +mod mutex; diff --git a/third_party/rust/futures-util/src/lock/mutex.rs b/third_party/rust/futures-util/src/lock/mutex.rs new file mode 100644 index 0000000000..335ad14273 --- /dev/null +++ b/third_party/rust/futures-util/src/lock/mutex.rs @@ -0,0 +1,551 @@ +use std::cell::UnsafeCell; +use std::marker::PhantomData; +use std::ops::{Deref, DerefMut}; +use std::pin::Pin; +use std::sync::atomic::{AtomicUsize, Ordering}; +use std::sync::{Arc, Mutex as StdMutex}; +use std::{fmt, mem}; + +use slab::Slab; + +use futures_core::future::{FusedFuture, Future}; +use futures_core::task::{Context, Poll, Waker}; + +/// A futures-aware mutex. +/// +/// # Fairness +/// +/// This mutex provides no fairness guarantees. Tasks may not acquire the mutex +/// in the order that they requested the lock, and it's possible for a single task +/// which repeatedly takes the lock to starve other tasks, which may be left waiting +/// indefinitely. +pub struct Mutex<T: ?Sized> { + state: AtomicUsize, + waiters: StdMutex<Slab<Waiter>>, + value: UnsafeCell<T>, +} + +impl<T: ?Sized> fmt::Debug for Mutex<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let state = self.state.load(Ordering::SeqCst); + f.debug_struct("Mutex") + .field("is_locked", &((state & IS_LOCKED) != 0)) + .field("has_waiters", &((state & HAS_WAITERS) != 0)) + .finish() + } +} + +impl<T> From<T> for Mutex<T> { + fn from(t: T) -> Self { + Self::new(t) + } +} + +impl<T: Default> Default for Mutex<T> { + fn default() -> Self { + Self::new(Default::default()) + } +} + +enum Waiter { + Waiting(Waker), + Woken, +} + +impl Waiter { + fn register(&mut self, waker: &Waker) { + match self { + Self::Waiting(w) if waker.will_wake(w) => {} + _ => *self = Self::Waiting(waker.clone()), + } + } + + fn wake(&mut self) { + match mem::replace(self, Self::Woken) { + Self::Waiting(waker) => waker.wake(), + Self::Woken => {} + } + } +} + +const IS_LOCKED: usize = 1 << 0; +const HAS_WAITERS: usize = 1 << 1; + +impl<T> Mutex<T> { + /// Creates a new futures-aware mutex. + pub fn new(t: T) -> Self { + Self { + state: AtomicUsize::new(0), + waiters: StdMutex::new(Slab::new()), + value: UnsafeCell::new(t), + } + } + + /// Consumes this mutex, returning the underlying data. + /// + /// # Examples + /// + /// ``` + /// use futures::lock::Mutex; + /// + /// let mutex = Mutex::new(0); + /// assert_eq!(mutex.into_inner(), 0); + /// ``` + pub fn into_inner(self) -> T { + self.value.into_inner() + } +} + +impl<T: ?Sized> Mutex<T> { + /// Attempt to acquire the lock immediately. + /// + /// If the lock is currently held, this will return `None`. + pub fn try_lock(&self) -> Option<MutexGuard<'_, T>> { + let old_state = self.state.fetch_or(IS_LOCKED, Ordering::Acquire); + if (old_state & IS_LOCKED) == 0 { + Some(MutexGuard { mutex: self }) + } else { + None + } + } + + /// Attempt to acquire the lock immediately. + /// + /// If the lock is currently held, this will return `None`. + pub fn try_lock_owned(self: &Arc<Self>) -> Option<OwnedMutexGuard<T>> { + let old_state = self.state.fetch_or(IS_LOCKED, Ordering::Acquire); + if (old_state & IS_LOCKED) == 0 { + Some(OwnedMutexGuard { mutex: self.clone() }) + } else { + None + } + } + + /// Acquire the lock asynchronously. + /// + /// This method returns a future that will resolve once the lock has been + /// successfully acquired. + pub fn lock(&self) -> MutexLockFuture<'_, T> { + MutexLockFuture { mutex: Some(self), wait_key: WAIT_KEY_NONE } + } + + /// Acquire the lock asynchronously. + /// + /// This method returns a future that will resolve once the lock has been + /// successfully acquired. + pub fn lock_owned(self: Arc<Self>) -> OwnedMutexLockFuture<T> { + OwnedMutexLockFuture { mutex: Some(self), wait_key: WAIT_KEY_NONE } + } + + /// Returns a mutable reference to the underlying data. + /// + /// Since this call borrows the `Mutex` mutably, no actual locking needs to + /// take place -- the mutable borrow statically guarantees no locks exist. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::lock::Mutex; + /// + /// let mut mutex = Mutex::new(0); + /// *mutex.get_mut() = 10; + /// assert_eq!(*mutex.lock().await, 10); + /// # }); + /// ``` + pub fn get_mut(&mut self) -> &mut T { + // We know statically that there are no other references to `self`, so + // there's no need to lock the inner mutex. + unsafe { &mut *self.value.get() } + } + + fn remove_waker(&self, wait_key: usize, wake_another: bool) { + if wait_key != WAIT_KEY_NONE { + let mut waiters = self.waiters.lock().unwrap(); + match waiters.remove(wait_key) { + Waiter::Waiting(_) => {} + Waiter::Woken => { + // We were awoken, but then dropped before we could + // wake up to acquire the lock. Wake up another + // waiter. + if wake_another { + if let Some((_i, waiter)) = waiters.iter_mut().next() { + waiter.wake(); + } + } + } + } + if waiters.is_empty() { + self.state.fetch_and(!HAS_WAITERS, Ordering::Relaxed); // released by mutex unlock + } + } + } + + // Unlocks the mutex. Called by MutexGuard and MappedMutexGuard when they are + // dropped. + fn unlock(&self) { + let old_state = self.state.fetch_and(!IS_LOCKED, Ordering::AcqRel); + if (old_state & HAS_WAITERS) != 0 { + let mut waiters = self.waiters.lock().unwrap(); + if let Some((_i, waiter)) = waiters.iter_mut().next() { + waiter.wake(); + } + } + } +} + +// Sentinel for when no slot in the `Slab` has been dedicated to this object. +const WAIT_KEY_NONE: usize = usize::MAX; + +/// A future which resolves when the target mutex has been successfully acquired, owned version. +pub struct OwnedMutexLockFuture<T: ?Sized> { + // `None` indicates that the mutex was successfully acquired. + mutex: Option<Arc<Mutex<T>>>, + wait_key: usize, +} + +impl<T: ?Sized> fmt::Debug for OwnedMutexLockFuture<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("OwnedMutexLockFuture") + .field("was_acquired", &self.mutex.is_none()) + .field("mutex", &self.mutex) + .field( + "wait_key", + &(if self.wait_key == WAIT_KEY_NONE { None } else { Some(self.wait_key) }), + ) + .finish() + } +} + +impl<T: ?Sized> FusedFuture for OwnedMutexLockFuture<T> { + fn is_terminated(&self) -> bool { + self.mutex.is_none() + } +} + +impl<T: ?Sized> Future for OwnedMutexLockFuture<T> { + type Output = OwnedMutexGuard<T>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = self.get_mut(); + + let mutex = this.mutex.as_ref().expect("polled OwnedMutexLockFuture after completion"); + + if let Some(lock) = mutex.try_lock_owned() { + mutex.remove_waker(this.wait_key, false); + this.mutex = None; + return Poll::Ready(lock); + } + + { + let mut waiters = mutex.waiters.lock().unwrap(); + if this.wait_key == WAIT_KEY_NONE { + this.wait_key = waiters.insert(Waiter::Waiting(cx.waker().clone())); + if waiters.len() == 1 { + mutex.state.fetch_or(HAS_WAITERS, Ordering::Relaxed); // released by mutex unlock + } + } else { + waiters[this.wait_key].register(cx.waker()); + } + } + + // Ensure that we haven't raced `MutexGuard::drop`'s unlock path by + // attempting to acquire the lock again. + if let Some(lock) = mutex.try_lock_owned() { + mutex.remove_waker(this.wait_key, false); + this.mutex = None; + return Poll::Ready(lock); + } + + Poll::Pending + } +} + +impl<T: ?Sized> Drop for OwnedMutexLockFuture<T> { + fn drop(&mut self) { + if let Some(mutex) = self.mutex.as_ref() { + // This future was dropped before it acquired the mutex. + // + // Remove ourselves from the map, waking up another waiter if we + // had been awoken to acquire the lock. + mutex.remove_waker(self.wait_key, true); + } + } +} + +/// An RAII guard returned by the `lock_owned` and `try_lock_owned` methods. +/// When this structure is dropped (falls out of scope), the lock will be +/// unlocked. +pub struct OwnedMutexGuard<T: ?Sized> { + mutex: Arc<Mutex<T>>, +} + +impl<T: ?Sized + fmt::Debug> fmt::Debug for OwnedMutexGuard<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("OwnedMutexGuard") + .field("value", &&**self) + .field("mutex", &self.mutex) + .finish() + } +} + +impl<T: ?Sized> Drop for OwnedMutexGuard<T> { + fn drop(&mut self) { + self.mutex.unlock() + } +} + +impl<T: ?Sized> Deref for OwnedMutexGuard<T> { + type Target = T; + fn deref(&self) -> &T { + unsafe { &*self.mutex.value.get() } + } +} + +impl<T: ?Sized> DerefMut for OwnedMutexGuard<T> { + fn deref_mut(&mut self) -> &mut T { + unsafe { &mut *self.mutex.value.get() } + } +} + +/// A future which resolves when the target mutex has been successfully acquired. +pub struct MutexLockFuture<'a, T: ?Sized> { + // `None` indicates that the mutex was successfully acquired. + mutex: Option<&'a Mutex<T>>, + wait_key: usize, +} + +impl<T: ?Sized> fmt::Debug for MutexLockFuture<'_, T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("MutexLockFuture") + .field("was_acquired", &self.mutex.is_none()) + .field("mutex", &self.mutex) + .field( + "wait_key", + &(if self.wait_key == WAIT_KEY_NONE { None } else { Some(self.wait_key) }), + ) + .finish() + } +} + +impl<T: ?Sized> FusedFuture for MutexLockFuture<'_, T> { + fn is_terminated(&self) -> bool { + self.mutex.is_none() + } +} + +impl<'a, T: ?Sized> Future for MutexLockFuture<'a, T> { + type Output = MutexGuard<'a, T>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mutex = self.mutex.expect("polled MutexLockFuture after completion"); + + if let Some(lock) = mutex.try_lock() { + mutex.remove_waker(self.wait_key, false); + self.mutex = None; + return Poll::Ready(lock); + } + + { + let mut waiters = mutex.waiters.lock().unwrap(); + if self.wait_key == WAIT_KEY_NONE { + self.wait_key = waiters.insert(Waiter::Waiting(cx.waker().clone())); + if waiters.len() == 1 { + mutex.state.fetch_or(HAS_WAITERS, Ordering::Relaxed); // released by mutex unlock + } + } else { + waiters[self.wait_key].register(cx.waker()); + } + } + + // Ensure that we haven't raced `MutexGuard::drop`'s unlock path by + // attempting to acquire the lock again. + if let Some(lock) = mutex.try_lock() { + mutex.remove_waker(self.wait_key, false); + self.mutex = None; + return Poll::Ready(lock); + } + + Poll::Pending + } +} + +impl<T: ?Sized> Drop for MutexLockFuture<'_, T> { + fn drop(&mut self) { + if let Some(mutex) = self.mutex { + // This future was dropped before it acquired the mutex. + // + // Remove ourselves from the map, waking up another waiter if we + // had been awoken to acquire the lock. + mutex.remove_waker(self.wait_key, true); + } + } +} + +/// An RAII guard returned by the `lock` and `try_lock` methods. +/// When this structure is dropped (falls out of scope), the lock will be +/// unlocked. +pub struct MutexGuard<'a, T: ?Sized> { + mutex: &'a Mutex<T>, +} + +impl<'a, T: ?Sized> MutexGuard<'a, T> { + /// Returns a locked view over a portion of the locked data. + /// + /// # Example + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::lock::{Mutex, MutexGuard}; + /// + /// let data = Mutex::new(Some("value".to_string())); + /// { + /// let locked_str = MutexGuard::map(data.lock().await, |opt| opt.as_mut().unwrap()); + /// assert_eq!(&*locked_str, "value"); + /// } + /// # }); + /// ``` + #[inline] + pub fn map<U: ?Sized, F>(this: Self, f: F) -> MappedMutexGuard<'a, T, U> + where + F: FnOnce(&mut T) -> &mut U, + { + let mutex = this.mutex; + let value = f(unsafe { &mut *this.mutex.value.get() }); + // Don't run the `drop` method for MutexGuard. The ownership of the underlying + // locked state is being moved to the returned MappedMutexGuard. + mem::forget(this); + MappedMutexGuard { mutex, value, _marker: PhantomData } + } +} + +impl<T: ?Sized + fmt::Debug> fmt::Debug for MutexGuard<'_, T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("MutexGuard").field("value", &&**self).field("mutex", &self.mutex).finish() + } +} + +impl<T: ?Sized> Drop for MutexGuard<'_, T> { + fn drop(&mut self) { + self.mutex.unlock() + } +} + +impl<T: ?Sized> Deref for MutexGuard<'_, T> { + type Target = T; + fn deref(&self) -> &T { + unsafe { &*self.mutex.value.get() } + } +} + +impl<T: ?Sized> DerefMut for MutexGuard<'_, T> { + fn deref_mut(&mut self) -> &mut T { + unsafe { &mut *self.mutex.value.get() } + } +} + +/// An RAII guard returned by the `MutexGuard::map` and `MappedMutexGuard::map` methods. +/// When this structure is dropped (falls out of scope), the lock will be unlocked. +pub struct MappedMutexGuard<'a, T: ?Sized, U: ?Sized> { + mutex: &'a Mutex<T>, + value: *mut U, + _marker: PhantomData<&'a mut U>, +} + +impl<'a, T: ?Sized, U: ?Sized> MappedMutexGuard<'a, T, U> { + /// Returns a locked view over a portion of the locked data. + /// + /// # Example + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::lock::{MappedMutexGuard, Mutex, MutexGuard}; + /// + /// let data = Mutex::new(Some("value".to_string())); + /// { + /// let locked_str = MutexGuard::map(data.lock().await, |opt| opt.as_mut().unwrap()); + /// let locked_char = MappedMutexGuard::map(locked_str, |s| s.get_mut(0..1).unwrap()); + /// assert_eq!(&*locked_char, "v"); + /// } + /// # }); + /// ``` + #[inline] + pub fn map<V: ?Sized, F>(this: Self, f: F) -> MappedMutexGuard<'a, T, V> + where + F: FnOnce(&mut U) -> &mut V, + { + let mutex = this.mutex; + let value = f(unsafe { &mut *this.value }); + // Don't run the `drop` method for MappedMutexGuard. The ownership of the underlying + // locked state is being moved to the returned MappedMutexGuard. + mem::forget(this); + MappedMutexGuard { mutex, value, _marker: PhantomData } + } +} + +impl<T: ?Sized, U: ?Sized + fmt::Debug> fmt::Debug for MappedMutexGuard<'_, T, U> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("MappedMutexGuard") + .field("value", &&**self) + .field("mutex", &self.mutex) + .finish() + } +} + +impl<T: ?Sized, U: ?Sized> Drop for MappedMutexGuard<'_, T, U> { + fn drop(&mut self) { + self.mutex.unlock() + } +} + +impl<T: ?Sized, U: ?Sized> Deref for MappedMutexGuard<'_, T, U> { + type Target = U; + fn deref(&self) -> &U { + unsafe { &*self.value } + } +} + +impl<T: ?Sized, U: ?Sized> DerefMut for MappedMutexGuard<'_, T, U> { + fn deref_mut(&mut self) -> &mut U { + unsafe { &mut *self.value } + } +} + +// Mutexes can be moved freely between threads and acquired on any thread so long +// as the inner value can be safely sent between threads. +unsafe impl<T: ?Sized + Send> Send for Mutex<T> {} +unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {} + +// It's safe to switch which thread the acquire is being attempted on so long as +// `T` can be accessed on that thread. +unsafe impl<T: ?Sized + Send> Send for MutexLockFuture<'_, T> {} + +// doesn't have any interesting `&self` methods (only Debug) +unsafe impl<T: ?Sized> Sync for MutexLockFuture<'_, T> {} + +// It's safe to switch which thread the acquire is being attempted on so long as +// `T` can be accessed on that thread. +unsafe impl<T: ?Sized + Send> Send for OwnedMutexLockFuture<T> {} + +// doesn't have any interesting `&self` methods (only Debug) +unsafe impl<T: ?Sized> Sync for OwnedMutexLockFuture<T> {} + +// Safe to send since we don't track any thread-specific details-- the inner +// lock is essentially spinlock-equivalent (attempt to flip an atomic bool) +unsafe impl<T: ?Sized + Send> Send for MutexGuard<'_, T> {} +unsafe impl<T: ?Sized + Sync> Sync for MutexGuard<'_, T> {} + +unsafe impl<T: ?Sized + Send> Send for OwnedMutexGuard<T> {} +unsafe impl<T: ?Sized + Sync> Sync for OwnedMutexGuard<T> {} + +unsafe impl<T: ?Sized + Send, U: ?Sized + Send> Send for MappedMutexGuard<'_, T, U> {} +unsafe impl<T: ?Sized + Sync, U: ?Sized + Sync> Sync for MappedMutexGuard<'_, T, U> {} + +#[test] +fn test_mutex_guard_debug_not_recurse() { + let mutex = Mutex::new(42); + let guard = mutex.try_lock().unwrap(); + let _ = format!("{:?}", guard); + let guard = MutexGuard::map(guard, |n| n); + let _ = format!("{:?}", guard); +} diff --git a/third_party/rust/futures-util/src/never.rs b/third_party/rust/futures-util/src/never.rs new file mode 100644 index 0000000000..e811f97df7 --- /dev/null +++ b/third_party/rust/futures-util/src/never.rs @@ -0,0 +1,18 @@ +//! This module contains the `Never` type. +//! +//! Values of this type can never be created and will never exist. + +/// A type with no possible values. +/// +/// This is used to indicate values which can never be created, such as the +/// error type of infallible futures. +/// +/// This type is a stable equivalent to the `!` type from `std`. +/// +/// This is currently an alias for [`std::convert::Infallible`], but in +/// the future it may be an alias for [`!`][never]. +/// See ["Future compatibility" section of `std::convert::Infallible`][infallible] for more. +/// +/// [never]: https://doc.rust-lang.org/nightly/std/primitive.never.html +/// [infallible]: https://doc.rust-lang.org/nightly/std/convert/enum.Infallible.html#future-compatibility +pub type Never = core::convert::Infallible; diff --git a/third_party/rust/futures-util/src/sink/buffer.rs b/third_party/rust/futures-util/src/sink/buffer.rs new file mode 100644 index 0000000000..4aa6c36033 --- /dev/null +++ b/third_party/rust/futures-util/src/sink/buffer.rs @@ -0,0 +1,105 @@ +use alloc::collections::VecDeque; +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Sink for the [`buffer`](super::SinkExt::buffer) method. + #[derive(Debug)] + #[must_use = "sinks do nothing unless polled"] + pub struct Buffer<Si, Item> { + #[pin] + sink: Si, + buf: VecDeque<Item>, + + // Track capacity separately from the `VecDeque`, which may be rounded up + capacity: usize, + } +} + +impl<Si: Sink<Item>, Item> Buffer<Si, Item> { + pub(super) fn new(sink: Si, capacity: usize) -> Self { + Self { sink, buf: VecDeque::with_capacity(capacity), capacity } + } + + delegate_access_inner!(sink, Si, ()); + + fn try_empty_buffer(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Si::Error>> { + let mut this = self.project(); + ready!(this.sink.as_mut().poll_ready(cx))?; + while let Some(item) = this.buf.pop_front() { + this.sink.as_mut().start_send(item)?; + if !this.buf.is_empty() { + ready!(this.sink.as_mut().poll_ready(cx))?; + } + } + Poll::Ready(Ok(())) + } +} + +// Forwarding impl of Stream from the underlying sink +impl<S, Item> Stream for Buffer<S, Item> +where + S: Sink<Item> + Stream, +{ + type Item = S::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<S::Item>> { + self.project().sink.poll_next(cx) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.sink.size_hint() + } +} + +impl<S, Item> FusedStream for Buffer<S, Item> +where + S: Sink<Item> + FusedStream, +{ + fn is_terminated(&self) -> bool { + self.sink.is_terminated() + } +} + +impl<Si: Sink<Item>, Item> Sink<Item> for Buffer<Si, Item> { + type Error = Si::Error; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + if self.capacity == 0 { + return self.project().sink.poll_ready(cx); + } + + let _ = self.as_mut().try_empty_buffer(cx)?; + + if self.buf.len() >= self.capacity { + Poll::Pending + } else { + Poll::Ready(Ok(())) + } + } + + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + if self.capacity == 0 { + self.project().sink.start_send(item) + } else { + self.project().buf.push_back(item); + Ok(()) + } + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.as_mut().try_empty_buffer(cx))?; + debug_assert!(self.buf.is_empty()); + self.project().sink.poll_flush(cx) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.as_mut().try_empty_buffer(cx))?; + debug_assert!(self.buf.is_empty()); + self.project().sink.poll_close(cx) + } +} diff --git a/third_party/rust/futures-util/src/sink/close.rs b/third_party/rust/futures-util/src/sink/close.rs new file mode 100644 index 0000000000..43eea74b0f --- /dev/null +++ b/third_party/rust/futures-util/src/sink/close.rs @@ -0,0 +1,32 @@ +use core::marker::PhantomData; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; + +/// Future for the [`close`](super::SinkExt::close) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Close<'a, Si: ?Sized, Item> { + sink: &'a mut Si, + _phantom: PhantomData<fn(Item)>, +} + +impl<Si: Unpin + ?Sized, Item> Unpin for Close<'_, Si, Item> {} + +/// A future that completes when the sink has finished closing. +/// +/// The sink itself is returned after closing is complete. +impl<'a, Si: Sink<Item> + Unpin + ?Sized, Item> Close<'a, Si, Item> { + pub(super) fn new(sink: &'a mut Si) -> Self { + Self { sink, _phantom: PhantomData } + } +} + +impl<Si: Sink<Item> + Unpin + ?Sized, Item> Future for Close<'_, Si, Item> { + type Output = Result<(), Si::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + Pin::new(&mut self.sink).poll_close(cx) + } +} diff --git a/third_party/rust/futures-util/src/sink/drain.rs b/third_party/rust/futures-util/src/sink/drain.rs new file mode 100644 index 0000000000..1a5480c0d6 --- /dev/null +++ b/third_party/rust/futures-util/src/sink/drain.rs @@ -0,0 +1,59 @@ +use super::assert_sink; +use crate::never::Never; +use core::marker::PhantomData; +use core::pin::Pin; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; + +/// Sink for the [`drain`] function. +#[derive(Debug)] +#[must_use = "sinks do nothing unless polled"] +pub struct Drain<T> { + marker: PhantomData<T>, +} + +/// Create a sink that will just discard all items given to it. +/// +/// Similar to [`io::Sink`](::std::io::Sink). +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::sink::{self, SinkExt}; +/// +/// let mut drain = sink::drain(); +/// drain.send(5).await?; +/// # Ok::<(), futures::never::Never>(()) }).unwrap(); +/// ``` +pub fn drain<T>() -> Drain<T> { + assert_sink::<T, Never, _>(Drain { marker: PhantomData }) +} + +impl<T> Unpin for Drain<T> {} + +impl<T> Clone for Drain<T> { + fn clone(&self) -> Self { + drain() + } +} + +impl<T> Sink<T> for Drain<T> { + type Error = Never; + + fn poll_ready(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + Poll::Ready(Ok(())) + } + + fn start_send(self: Pin<&mut Self>, _item: T) -> Result<(), Self::Error> { + Ok(()) + } + + fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + Poll::Ready(Ok(())) + } + + fn poll_close(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + Poll::Ready(Ok(())) + } +} diff --git a/third_party/rust/futures-util/src/sink/err_into.rs b/third_party/rust/futures-util/src/sink/err_into.rs new file mode 100644 index 0000000000..a64d1337ba --- /dev/null +++ b/third_party/rust/futures-util/src/sink/err_into.rs @@ -0,0 +1,57 @@ +use crate::sink::{SinkExt, SinkMapErr}; +use futures_core::stream::{FusedStream, Stream}; +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Sink for the [`sink_err_into`](super::SinkExt::sink_err_into) method. + #[derive(Debug)] + #[must_use = "sinks do nothing unless polled"] + pub struct SinkErrInto<Si: Sink<Item>, Item, E> { + #[pin] + sink: SinkMapErr<Si, fn(Si::Error) -> E>, + } +} + +impl<Si, E, Item> SinkErrInto<Si, Item, E> +where + Si: Sink<Item>, + Si::Error: Into<E>, +{ + pub(super) fn new(sink: Si) -> Self { + Self { sink: SinkExt::sink_map_err(sink, Into::into) } + } + + delegate_access_inner!(sink, Si, (.)); +} + +impl<Si, Item, E> Sink<Item> for SinkErrInto<Si, Item, E> +where + Si: Sink<Item>, + Si::Error: Into<E>, +{ + type Error = E; + + delegate_sink!(sink, Item); +} + +// Forwarding impl of Stream from the underlying sink +impl<S, Item, E> Stream for SinkErrInto<S, Item, E> +where + S: Sink<Item> + Stream, + S::Error: Into<E>, +{ + type Item = S::Item; + + delegate_stream!(sink); +} + +impl<S, Item, E> FusedStream for SinkErrInto<S, Item, E> +where + S: Sink<Item> + FusedStream, + S::Error: Into<E>, +{ + fn is_terminated(&self) -> bool { + self.sink.is_terminated() + } +} diff --git a/third_party/rust/futures-util/src/sink/fanout.rs b/third_party/rust/futures-util/src/sink/fanout.rs new file mode 100644 index 0000000000..fe2038f27f --- /dev/null +++ b/third_party/rust/futures-util/src/sink/fanout.rs @@ -0,0 +1,111 @@ +use core::fmt::{Debug, Formatter, Result as FmtResult}; +use core::pin::Pin; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Sink that clones incoming items and forwards them to two sinks at the same time. + /// + /// Backpressure from any downstream sink propagates up, which means that this sink + /// can only process items as fast as its _slowest_ downstream sink. + #[must_use = "sinks do nothing unless polled"] + pub struct Fanout<Si1, Si2> { + #[pin] + sink1: Si1, + #[pin] + sink2: Si2 + } +} + +impl<Si1, Si2> Fanout<Si1, Si2> { + pub(super) fn new(sink1: Si1, sink2: Si2) -> Self { + Self { sink1, sink2 } + } + + /// Get a shared reference to the inner sinks. + pub fn get_ref(&self) -> (&Si1, &Si2) { + (&self.sink1, &self.sink2) + } + + /// Get a mutable reference to the inner sinks. + pub fn get_mut(&mut self) -> (&mut Si1, &mut Si2) { + (&mut self.sink1, &mut self.sink2) + } + + /// Get a pinned mutable reference to the inner sinks. + pub fn get_pin_mut(self: Pin<&mut Self>) -> (Pin<&mut Si1>, Pin<&mut Si2>) { + let this = self.project(); + (this.sink1, this.sink2) + } + + /// Consumes this combinator, returning the underlying sinks. + /// + /// Note that this may discard intermediate state of this combinator, + /// so care should be taken to avoid losing resources when this is called. + pub fn into_inner(self) -> (Si1, Si2) { + (self.sink1, self.sink2) + } +} + +impl<Si1: Debug, Si2: Debug> Debug for Fanout<Si1, Si2> { + fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult { + f.debug_struct("Fanout").field("sink1", &self.sink1).field("sink2", &self.sink2).finish() + } +} + +impl<Si1, Si2, Item> Sink<Item> for Fanout<Si1, Si2> +where + Si1: Sink<Item>, + Item: Clone, + Si2: Sink<Item, Error = Si1::Error>, +{ + type Error = Si1::Error; + + fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + let this = self.project(); + + let sink1_ready = this.sink1.poll_ready(cx)?.is_ready(); + let sink2_ready = this.sink2.poll_ready(cx)?.is_ready(); + let ready = sink1_ready && sink2_ready; + if ready { + Poll::Ready(Ok(())) + } else { + Poll::Pending + } + } + + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + let this = self.project(); + + this.sink1.start_send(item.clone())?; + this.sink2.start_send(item)?; + Ok(()) + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + let this = self.project(); + + let sink1_ready = this.sink1.poll_flush(cx)?.is_ready(); + let sink2_ready = this.sink2.poll_flush(cx)?.is_ready(); + let ready = sink1_ready && sink2_ready; + if ready { + Poll::Ready(Ok(())) + } else { + Poll::Pending + } + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + let this = self.project(); + + let sink1_ready = this.sink1.poll_close(cx)?.is_ready(); + let sink2_ready = this.sink2.poll_close(cx)?.is_ready(); + let ready = sink1_ready && sink2_ready; + if ready { + Poll::Ready(Ok(())) + } else { + Poll::Pending + } + } +} diff --git a/third_party/rust/futures-util/src/sink/feed.rs b/third_party/rust/futures-util/src/sink/feed.rs new file mode 100644 index 0000000000..6701f7a1b4 --- /dev/null +++ b/third_party/rust/futures-util/src/sink/feed.rs @@ -0,0 +1,43 @@ +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; + +/// Future for the [`feed`](super::SinkExt::feed) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Feed<'a, Si: ?Sized, Item> { + sink: &'a mut Si, + item: Option<Item>, +} + +// Pinning is never projected to children +impl<Si: Unpin + ?Sized, Item> Unpin for Feed<'_, Si, Item> {} + +impl<'a, Si: Sink<Item> + Unpin + ?Sized, Item> Feed<'a, Si, Item> { + pub(super) fn new(sink: &'a mut Si, item: Item) -> Self { + Feed { sink, item: Some(item) } + } + + pub(super) fn sink_pin_mut(&mut self) -> Pin<&mut Si> { + Pin::new(self.sink) + } + + pub(super) fn is_item_pending(&self) -> bool { + self.item.is_some() + } +} + +impl<Si: Sink<Item> + Unpin + ?Sized, Item> Future for Feed<'_, Si, Item> { + type Output = Result<(), Si::Error>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = self.get_mut(); + let mut sink = Pin::new(&mut this.sink); + ready!(sink.as_mut().poll_ready(cx))?; + let item = this.item.take().expect("polled Feed after completion"); + sink.as_mut().start_send(item)?; + Poll::Ready(Ok(())) + } +} diff --git a/third_party/rust/futures-util/src/sink/flush.rs b/third_party/rust/futures-util/src/sink/flush.rs new file mode 100644 index 0000000000..35a8372de7 --- /dev/null +++ b/third_party/rust/futures-util/src/sink/flush.rs @@ -0,0 +1,36 @@ +use core::marker::PhantomData; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; + +/// Future for the [`flush`](super::SinkExt::flush) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Flush<'a, Si: ?Sized, Item> { + sink: &'a mut Si, + _phantom: PhantomData<fn(Item)>, +} + +// Pin is never projected to a field. +impl<Si: Unpin + ?Sized, Item> Unpin for Flush<'_, Si, Item> {} + +/// A future that completes when the sink has finished processing all +/// pending requests. +/// +/// The sink itself is returned after flushing is complete; this adapter is +/// intended to be used when you want to stop sending to the sink until +/// all current requests are processed. +impl<'a, Si: Sink<Item> + Unpin + ?Sized, Item> Flush<'a, Si, Item> { + pub(super) fn new(sink: &'a mut Si) -> Self { + Self { sink, _phantom: PhantomData } + } +} + +impl<Si: Sink<Item> + Unpin + ?Sized, Item> Future for Flush<'_, Si, Item> { + type Output = Result<(), Si::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + Pin::new(&mut self.sink).poll_flush(cx) + } +} diff --git a/third_party/rust/futures-util/src/sink/map_err.rs b/third_party/rust/futures-util/src/sink/map_err.rs new file mode 100644 index 0000000000..9d2ab7b24b --- /dev/null +++ b/third_party/rust/futures-util/src/sink/map_err.rs @@ -0,0 +1,65 @@ +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Sink for the [`sink_map_err`](super::SinkExt::sink_map_err) method. + #[derive(Debug, Clone)] + #[must_use = "sinks do nothing unless polled"] + pub struct SinkMapErr<Si, F> { + #[pin] + sink: Si, + f: Option<F>, + } +} + +impl<Si, F> SinkMapErr<Si, F> { + pub(super) fn new(sink: Si, f: F) -> Self { + Self { sink, f: Some(f) } + } + + delegate_access_inner!(sink, Si, ()); + + fn take_f(self: Pin<&mut Self>) -> F { + self.project().f.take().expect("polled MapErr after completion") + } +} + +impl<Si, F, E, Item> Sink<Item> for SinkMapErr<Si, F> +where + Si: Sink<Item>, + F: FnOnce(Si::Error) -> E, +{ + type Error = E; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + self.as_mut().project().sink.poll_ready(cx).map_err(|e| self.as_mut().take_f()(e)) + } + + fn start_send(mut self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + self.as_mut().project().sink.start_send(item).map_err(|e| self.as_mut().take_f()(e)) + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + self.as_mut().project().sink.poll_flush(cx).map_err(|e| self.as_mut().take_f()(e)) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + self.as_mut().project().sink.poll_close(cx).map_err(|e| self.as_mut().take_f()(e)) + } +} + +// Forwarding impl of Stream from the underlying sink +impl<S: Stream, F> Stream for SinkMapErr<S, F> { + type Item = S::Item; + + delegate_stream!(sink); +} + +impl<S: FusedStream, F> FusedStream for SinkMapErr<S, F> { + fn is_terminated(&self) -> bool { + self.sink.is_terminated() + } +} diff --git a/third_party/rust/futures-util/src/sink/mod.rs b/third_party/rust/futures-util/src/sink/mod.rs new file mode 100644 index 0000000000..147e9adc93 --- /dev/null +++ b/third_party/rust/futures-util/src/sink/mod.rs @@ -0,0 +1,344 @@ +//! Asynchronous sinks. +//! +//! This module contains: +//! +//! - The [`Sink`] trait, which allows you to asynchronously write data. +//! - The [`SinkExt`] trait, which provides adapters for chaining and composing +//! sinks. + +use crate::future::{assert_future, Either}; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::stream::{Stream, TryStream}; +use futures_core::task::{Context, Poll}; + +#[cfg(feature = "compat")] +use crate::compat::CompatSink; + +pub use futures_sink::Sink; + +mod close; +pub use self::close::Close; + +mod drain; +pub use self::drain::{drain, Drain}; + +mod fanout; +pub use self::fanout::Fanout; + +mod feed; +pub use self::feed::Feed; + +mod flush; +pub use self::flush::Flush; + +mod err_into; +pub use self::err_into::SinkErrInto; + +mod map_err; +pub use self::map_err::SinkMapErr; + +mod send; +pub use self::send::Send; + +mod send_all; +pub use self::send_all::SendAll; + +mod unfold; +pub use self::unfold::{unfold, Unfold}; + +mod with; +pub use self::with::With; + +mod with_flat_map; +pub use self::with_flat_map::WithFlatMap; + +#[cfg(feature = "alloc")] +mod buffer; +#[cfg(feature = "alloc")] +pub use self::buffer::Buffer; + +impl<T: ?Sized, Item> SinkExt<Item> for T where T: Sink<Item> {} + +/// An extension trait for `Sink`s that provides a variety of convenient +/// combinator functions. +pub trait SinkExt<Item>: Sink<Item> { + /// Composes a function *in front of* the sink. + /// + /// This adapter produces a new sink that passes each value through the + /// given function `f` before sending it to `self`. + /// + /// To process each value, `f` produces a *future*, which is then polled to + /// completion before passing its result down to the underlying sink. If the + /// future produces an error, that error is returned by the new sink. + /// + /// Note that this function consumes the given sink, returning a wrapped + /// version, much like `Iterator::map`. + fn with<U, Fut, F, E>(self, f: F) -> With<Self, Item, U, Fut, F> + where + F: FnMut(U) -> Fut, + Fut: Future<Output = Result<Item, E>>, + E: From<Self::Error>, + Self: Sized, + { + assert_sink::<U, E, _>(With::new(self, f)) + } + + /// Composes a function *in front of* the sink. + /// + /// This adapter produces a new sink that passes each value through the + /// given function `f` before sending it to `self`. + /// + /// To process each value, `f` produces a *stream*, of which each value + /// is passed to the underlying sink. A new value will not be accepted until + /// the stream has been drained + /// + /// Note that this function consumes the given sink, returning a wrapped + /// version, much like `Iterator::flat_map`. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::sink::SinkExt; + /// use futures::stream::{self, StreamExt}; + /// + /// let (tx, rx) = mpsc::channel(5); + /// + /// let mut tx = tx.with_flat_map(|x| { + /// stream::iter(vec![Ok(42); x]) + /// }); + /// + /// tx.send(5).await.unwrap(); + /// drop(tx); + /// let received: Vec<i32> = rx.collect().await; + /// assert_eq!(received, vec![42, 42, 42, 42, 42]); + /// # }); + /// ``` + fn with_flat_map<U, St, F>(self, f: F) -> WithFlatMap<Self, Item, U, St, F> + where + F: FnMut(U) -> St, + St: Stream<Item = Result<Item, Self::Error>>, + Self: Sized, + { + assert_sink::<U, Self::Error, _>(WithFlatMap::new(self, f)) + } + + /* + fn with_map<U, F>(self, f: F) -> WithMap<Self, U, F> + where F: FnMut(U) -> Self::SinkItem, + Self: Sized; + + fn with_filter<F>(self, f: F) -> WithFilter<Self, F> + where F: FnMut(Self::SinkItem) -> bool, + Self: Sized; + + fn with_filter_map<U, F>(self, f: F) -> WithFilterMap<Self, U, F> + where F: FnMut(U) -> Option<Self::SinkItem>, + Self: Sized; + */ + + /// Transforms the error returned by the sink. + fn sink_map_err<E, F>(self, f: F) -> SinkMapErr<Self, F> + where + F: FnOnce(Self::Error) -> E, + Self: Sized, + { + assert_sink::<Item, E, _>(SinkMapErr::new(self, f)) + } + + /// Map this sink's error to a different error type using the `Into` trait. + /// + /// If wanting to map errors of a `Sink + Stream`, use `.sink_err_into().err_into()`. + fn sink_err_into<E>(self) -> err_into::SinkErrInto<Self, Item, E> + where + Self: Sized, + Self::Error: Into<E>, + { + assert_sink::<Item, E, _>(SinkErrInto::new(self)) + } + + /// Adds a fixed-size buffer to the current sink. + /// + /// The resulting sink will buffer up to `capacity` items when the + /// underlying sink is unwilling to accept additional items. Calling `flush` + /// on the buffered sink will attempt to both empty the buffer and complete + /// processing on the underlying sink. + /// + /// Note that this function consumes the given sink, returning a wrapped + /// version, much like `Iterator::map`. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + #[cfg(feature = "alloc")] + fn buffer(self, capacity: usize) -> Buffer<Self, Item> + where + Self: Sized, + { + assert_sink::<Item, Self::Error, _>(Buffer::new(self, capacity)) + } + + /// Close the sink. + fn close(&mut self) -> Close<'_, Self, Item> + where + Self: Unpin, + { + assert_future::<Result<(), Self::Error>, _>(Close::new(self)) + } + + /// Fanout items to multiple sinks. + /// + /// This adapter clones each incoming item and forwards it to both this as well as + /// the other sink at the same time. + fn fanout<Si>(self, other: Si) -> Fanout<Self, Si> + where + Self: Sized, + Item: Clone, + Si: Sink<Item, Error = Self::Error>, + { + assert_sink::<Item, Self::Error, _>(Fanout::new(self, other)) + } + + /// Flush the sink, processing all pending items. + /// + /// This adapter is intended to be used when you want to stop sending to the sink + /// until all current requests are processed. + fn flush(&mut self) -> Flush<'_, Self, Item> + where + Self: Unpin, + { + assert_future::<Result<(), Self::Error>, _>(Flush::new(self)) + } + + /// A future that completes after the given item has been fully processed + /// into the sink, including flushing. + /// + /// Note that, **because of the flushing requirement, it is usually better + /// to batch together items to send via `feed` or `send_all`, + /// rather than flushing between each item.** + fn send(&mut self, item: Item) -> Send<'_, Self, Item> + where + Self: Unpin, + { + assert_future::<Result<(), Self::Error>, _>(Send::new(self, item)) + } + + /// A future that completes after the given item has been received + /// by the sink. + /// + /// Unlike `send`, the returned future does not flush the sink. + /// It is the caller's responsibility to ensure all pending items + /// are processed, which can be done via `flush` or `close`. + fn feed(&mut self, item: Item) -> Feed<'_, Self, Item> + where + Self: Unpin, + { + assert_future::<Result<(), Self::Error>, _>(Feed::new(self, item)) + } + + /// A future that completes after the given stream has been fully processed + /// into the sink, including flushing. + /// + /// This future will drive the stream to keep producing items until it is + /// exhausted, sending each item to the sink. It will complete once both the + /// stream is exhausted, the sink has received all items, and the sink has + /// been flushed. Note that the sink is **not** closed. If the stream produces + /// an error, that error will be returned by this future without flushing the sink. + /// + /// Doing `sink.send_all(stream)` is roughly equivalent to + /// `stream.forward(sink)`. The returned future will exhaust all items from + /// `stream` and send them to `self`. + fn send_all<'a, St>(&'a mut self, stream: &'a mut St) -> SendAll<'a, Self, St> + where + St: TryStream<Ok = Item, Error = Self::Error> + Stream + Unpin + ?Sized, + // St: Stream<Item = Result<Item, Self::Error>> + Unpin + ?Sized, + Self: Unpin, + { + // TODO: type mismatch resolving `<St as Stream>::Item == std::result::Result<Item, <Self as futures_sink::Sink<Item>>::Error>` + // assert_future::<Result<(), Self::Error>, _>(SendAll::new(self, stream)) + SendAll::new(self, stream) + } + + /// Wrap this sink in an `Either` sink, making it the left-hand variant + /// of that `Either`. + /// + /// This can be used in combination with the `right_sink` method to write `if` + /// statements that evaluate to different streams in different branches. + fn left_sink<Si2>(self) -> Either<Self, Si2> + where + Si2: Sink<Item, Error = Self::Error>, + Self: Sized, + { + assert_sink::<Item, Self::Error, _>(Either::Left(self)) + } + + /// Wrap this stream in an `Either` stream, making it the right-hand variant + /// of that `Either`. + /// + /// This can be used in combination with the `left_sink` method to write `if` + /// statements that evaluate to different streams in different branches. + fn right_sink<Si1>(self) -> Either<Si1, Self> + where + Si1: Sink<Item, Error = Self::Error>, + Self: Sized, + { + assert_sink::<Item, Self::Error, _>(Either::Right(self)) + } + + /// Wraps a [`Sink`] into a sink compatible with libraries using + /// futures 0.1 `Sink`. Requires the `compat` feature to be enabled. + #[cfg(feature = "compat")] + #[cfg_attr(docsrs, doc(cfg(feature = "compat")))] + fn compat(self) -> CompatSink<Self, Item> + where + Self: Sized + Unpin, + { + CompatSink::new(self) + } + + /// A convenience method for calling [`Sink::poll_ready`] on [`Unpin`] + /// sink types. + fn poll_ready_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> + where + Self: Unpin, + { + Pin::new(self).poll_ready(cx) + } + + /// A convenience method for calling [`Sink::start_send`] on [`Unpin`] + /// sink types. + fn start_send_unpin(&mut self, item: Item) -> Result<(), Self::Error> + where + Self: Unpin, + { + Pin::new(self).start_send(item) + } + + /// A convenience method for calling [`Sink::poll_flush`] on [`Unpin`] + /// sink types. + fn poll_flush_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> + where + Self: Unpin, + { + Pin::new(self).poll_flush(cx) + } + + /// A convenience method for calling [`Sink::poll_close`] on [`Unpin`] + /// sink types. + fn poll_close_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> + where + Self: Unpin, + { + Pin::new(self).poll_close(cx) + } +} + +// Just a helper function to ensure the sinks we're returning all have the +// right implementations. +pub(crate) fn assert_sink<T, E, S>(sink: S) -> S +where + S: Sink<T, Error = E>, +{ + sink +} diff --git a/third_party/rust/futures-util/src/sink/send.rs b/third_party/rust/futures-util/src/sink/send.rs new file mode 100644 index 0000000000..6d21f33fe4 --- /dev/null +++ b/third_party/rust/futures-util/src/sink/send.rs @@ -0,0 +1,41 @@ +use super::Feed; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; + +/// Future for the [`send`](super::SinkExt::send) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Send<'a, Si: ?Sized, Item> { + feed: Feed<'a, Si, Item>, +} + +// Pinning is never projected to children +impl<Si: Unpin + ?Sized, Item> Unpin for Send<'_, Si, Item> {} + +impl<'a, Si: Sink<Item> + Unpin + ?Sized, Item> Send<'a, Si, Item> { + pub(super) fn new(sink: &'a mut Si, item: Item) -> Self { + Self { feed: Feed::new(sink, item) } + } +} + +impl<Si: Sink<Item> + Unpin + ?Sized, Item> Future for Send<'_, Si, Item> { + type Output = Result<(), Si::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + + if this.feed.is_item_pending() { + ready!(Pin::new(&mut this.feed).poll(cx))?; + debug_assert!(!this.feed.is_item_pending()); + } + + // we're done sending the item, but want to block on flushing the + // sink + ready!(this.feed.sink_pin_mut().poll_flush(cx))?; + + Poll::Ready(Ok(())) + } +} diff --git a/third_party/rust/futures-util/src/sink/send_all.rs b/third_party/rust/futures-util/src/sink/send_all.rs new file mode 100644 index 0000000000..1302dd2148 --- /dev/null +++ b/third_party/rust/futures-util/src/sink/send_all.rs @@ -0,0 +1,100 @@ +use crate::stream::{Fuse, StreamExt, TryStreamExt}; +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{Stream, TryStream}; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; + +/// Future for the [`send_all`](super::SinkExt::send_all) method. +#[allow(explicit_outlives_requirements)] // https://github.com/rust-lang/rust/issues/60993 +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct SendAll<'a, Si, St> +where + Si: ?Sized, + St: ?Sized + TryStream, +{ + sink: &'a mut Si, + stream: Fuse<&'a mut St>, + buffered: Option<St::Ok>, +} + +impl<Si, St> fmt::Debug for SendAll<'_, Si, St> +where + Si: fmt::Debug + ?Sized, + St: fmt::Debug + ?Sized + TryStream, + St::Ok: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("SendAll") + .field("sink", &self.sink) + .field("stream", &self.stream) + .field("buffered", &self.buffered) + .finish() + } +} + +// Pinning is never projected to any fields +impl<Si, St> Unpin for SendAll<'_, Si, St> +where + Si: Unpin + ?Sized, + St: TryStream + Unpin + ?Sized, +{ +} + +impl<'a, Si, St, Ok, Error> SendAll<'a, Si, St> +where + Si: Sink<Ok, Error = Error> + Unpin + ?Sized, + St: TryStream<Ok = Ok, Error = Error> + Stream + Unpin + ?Sized, +{ + pub(super) fn new(sink: &'a mut Si, stream: &'a mut St) -> Self { + Self { sink, stream: stream.fuse(), buffered: None } + } + + fn try_start_send( + &mut self, + cx: &mut Context<'_>, + item: St::Ok, + ) -> Poll<Result<(), Si::Error>> { + debug_assert!(self.buffered.is_none()); + match Pin::new(&mut self.sink).poll_ready(cx)? { + Poll::Ready(()) => Poll::Ready(Pin::new(&mut self.sink).start_send(item)), + Poll::Pending => { + self.buffered = Some(item); + Poll::Pending + } + } + } +} + +impl<Si, St, Ok, Error> Future for SendAll<'_, Si, St> +where + Si: Sink<Ok, Error = Error> + Unpin + ?Sized, + St: Stream<Item = Result<Ok, Error>> + Unpin + ?Sized, +{ + type Output = Result<(), Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + // If we've got an item buffered already, we need to write it to the + // sink before we can do anything else + if let Some(item) = this.buffered.take() { + ready!(this.try_start_send(cx, item))? + } + + loop { + match this.stream.try_poll_next_unpin(cx)? { + Poll::Ready(Some(item)) => ready!(this.try_start_send(cx, item))?, + Poll::Ready(None) => { + ready!(Pin::new(&mut this.sink).poll_flush(cx))?; + return Poll::Ready(Ok(())); + } + Poll::Pending => { + ready!(Pin::new(&mut this.sink).poll_flush(cx))?; + return Poll::Pending; + } + } + } + } +} diff --git a/third_party/rust/futures-util/src/sink/unfold.rs b/third_party/rust/futures-util/src/sink/unfold.rs new file mode 100644 index 0000000000..dea1307b66 --- /dev/null +++ b/third_party/rust/futures-util/src/sink/unfold.rs @@ -0,0 +1,89 @@ +use super::assert_sink; +use crate::unfold_state::UnfoldState; +use core::{future::Future, pin::Pin}; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Sink for the [`unfold`] function. + #[derive(Debug)] + #[must_use = "sinks do nothing unless polled"] + pub struct Unfold<T, F, R> { + function: F, + #[pin] + state: UnfoldState<T, R>, + } +} + +/// Create a sink from a function which processes one item at a time. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::sink::{self, SinkExt}; +/// +/// let unfold = sink::unfold(0, |mut sum, i: i32| { +/// async move { +/// sum += i; +/// eprintln!("{}", i); +/// Ok::<_, futures::never::Never>(sum) +/// } +/// }); +/// futures::pin_mut!(unfold); +/// unfold.send(5).await?; +/// # Ok::<(), futures::never::Never>(()) }).unwrap(); +/// ``` +pub fn unfold<T, F, R, Item, E>(init: T, function: F) -> Unfold<T, F, R> +where + F: FnMut(T, Item) -> R, + R: Future<Output = Result<T, E>>, +{ + assert_sink::<Item, E, _>(Unfold { function, state: UnfoldState::Value { value: init } }) +} + +impl<T, F, R, Item, E> Sink<Item> for Unfold<T, F, R> +where + F: FnMut(T, Item) -> R, + R: Future<Output = Result<T, E>>, +{ + type Error = E; + + fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + self.poll_flush(cx) + } + + fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { + let mut this = self.project(); + let future = match this.state.as_mut().take_value() { + Some(value) => (this.function)(value, item), + None => panic!("start_send called without poll_ready being called first"), + }; + this.state.set(UnfoldState::Future { future }); + Ok(()) + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + let mut this = self.project(); + Poll::Ready(if let Some(future) = this.state.as_mut().project_future() { + match ready!(future.poll(cx)) { + Ok(state) => { + this.state.set(UnfoldState::Value { value: state }); + Ok(()) + } + Err(err) => { + this.state.set(UnfoldState::Empty); + Err(err) + } + } + } else { + Ok(()) + }) + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + self.poll_flush(cx) + } +} diff --git a/third_party/rust/futures-util/src/sink/with.rs b/third_party/rust/futures-util/src/sink/with.rs new file mode 100644 index 0000000000..86d3dcc7b8 --- /dev/null +++ b/third_party/rust/futures-util/src/sink/with.rs @@ -0,0 +1,134 @@ +use core::fmt; +use core::marker::PhantomData; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Sink for the [`with`](super::SinkExt::with) method. + #[must_use = "sinks do nothing unless polled"] + pub struct With<Si, Item, U, Fut, F> { + #[pin] + sink: Si, + f: F, + #[pin] + state: Option<Fut>, + _phantom: PhantomData<fn(U) -> Item>, + } +} + +impl<Si, Item, U, Fut, F> fmt::Debug for With<Si, Item, U, Fut, F> +where + Si: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("With").field("sink", &self.sink).field("state", &self.state).finish() + } +} + +impl<Si, Item, U, Fut, F> With<Si, Item, U, Fut, F> +where + Si: Sink<Item>, + F: FnMut(U) -> Fut, + Fut: Future, +{ + pub(super) fn new<E>(sink: Si, f: F) -> Self + where + Fut: Future<Output = Result<Item, E>>, + E: From<Si::Error>, + { + Self { state: None, sink, f, _phantom: PhantomData } + } +} + +impl<Si, Item, U, Fut, F> Clone for With<Si, Item, U, Fut, F> +where + Si: Clone, + F: Clone, + Fut: Clone, +{ + fn clone(&self) -> Self { + Self { + state: self.state.clone(), + sink: self.sink.clone(), + f: self.f.clone(), + _phantom: PhantomData, + } + } +} + +// Forwarding impl of Stream from the underlying sink +impl<S, Item, U, Fut, F> Stream for With<S, Item, U, Fut, F> +where + S: Stream + Sink<Item>, + F: FnMut(U) -> Fut, + Fut: Future, +{ + type Item = S::Item; + + delegate_stream!(sink); +} + +impl<Si, Item, U, Fut, F, E> With<Si, Item, U, Fut, F> +where + Si: Sink<Item>, + F: FnMut(U) -> Fut, + Fut: Future<Output = Result<Item, E>>, + E: From<Si::Error>, +{ + delegate_access_inner!(sink, Si, ()); + + /// Completes the processing of previous item if any. + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), E>> { + let mut this = self.project(); + + let item = match this.state.as_mut().as_pin_mut() { + None => return Poll::Ready(Ok(())), + Some(fut) => ready!(fut.poll(cx))?, + }; + this.state.set(None); + this.sink.start_send(item)?; + Poll::Ready(Ok(())) + } +} + +impl<Si, Item, U, Fut, F, E> Sink<U> for With<Si, Item, U, Fut, F> +where + Si: Sink<Item>, + F: FnMut(U) -> Fut, + Fut: Future<Output = Result<Item, E>>, + E: From<Si::Error>, +{ + type Error = E; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.as_mut().poll(cx))?; + ready!(self.project().sink.poll_ready(cx)?); + Poll::Ready(Ok(())) + } + + fn start_send(self: Pin<&mut Self>, item: U) -> Result<(), Self::Error> { + let mut this = self.project(); + + assert!(this.state.is_none()); + this.state.set(Some((this.f)(item))); + Ok(()) + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.as_mut().poll(cx))?; + ready!(self.project().sink.poll_flush(cx)?); + Poll::Ready(Ok(())) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.as_mut().poll(cx))?; + ready!(self.project().sink.poll_close(cx)?); + Poll::Ready(Ok(())) + } +} diff --git a/third_party/rust/futures-util/src/sink/with_flat_map.rs b/third_party/rust/futures-util/src/sink/with_flat_map.rs new file mode 100644 index 0000000000..2ae877a24b --- /dev/null +++ b/third_party/rust/futures-util/src/sink/with_flat_map.rs @@ -0,0 +1,127 @@ +use core::fmt; +use core::marker::PhantomData; +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Sink for the [`with_flat_map`](super::SinkExt::with_flat_map) method. + #[must_use = "sinks do nothing unless polled"] + pub struct WithFlatMap<Si, Item, U, St, F> { + #[pin] + sink: Si, + f: F, + #[pin] + stream: Option<St>, + buffer: Option<Item>, + _marker: PhantomData<fn(U)>, + } +} + +impl<Si, Item, U, St, F> fmt::Debug for WithFlatMap<Si, Item, U, St, F> +where + Si: fmt::Debug, + St: fmt::Debug, + Item: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("WithFlatMap") + .field("sink", &self.sink) + .field("stream", &self.stream) + .field("buffer", &self.buffer) + .finish() + } +} + +impl<Si, Item, U, St, F> WithFlatMap<Si, Item, U, St, F> +where + Si: Sink<Item>, + F: FnMut(U) -> St, + St: Stream<Item = Result<Item, Si::Error>>, +{ + pub(super) fn new(sink: Si, f: F) -> Self { + Self { sink, f, stream: None, buffer: None, _marker: PhantomData } + } + + delegate_access_inner!(sink, Si, ()); + + fn try_empty_stream(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Si::Error>> { + let mut this = self.project(); + + if this.buffer.is_some() { + ready!(this.sink.as_mut().poll_ready(cx))?; + let item = this.buffer.take().unwrap(); + this.sink.as_mut().start_send(item)?; + } + if let Some(mut some_stream) = this.stream.as_mut().as_pin_mut() { + while let Some(item) = ready!(some_stream.as_mut().poll_next(cx)?) { + match this.sink.as_mut().poll_ready(cx)? { + Poll::Ready(()) => this.sink.as_mut().start_send(item)?, + Poll::Pending => { + *this.buffer = Some(item); + return Poll::Pending; + } + }; + } + } + this.stream.set(None); + Poll::Ready(Ok(())) + } +} + +// Forwarding impl of Stream from the underlying sink +impl<S, Item, U, St, F> Stream for WithFlatMap<S, Item, U, St, F> +where + S: Stream + Sink<Item>, + F: FnMut(U) -> St, + St: Stream<Item = Result<Item, S::Error>>, +{ + type Item = S::Item; + + delegate_stream!(sink); +} + +impl<S, Item, U, St, F> FusedStream for WithFlatMap<S, Item, U, St, F> +where + S: FusedStream + Sink<Item>, + F: FnMut(U) -> St, + St: Stream<Item = Result<Item, S::Error>>, +{ + fn is_terminated(&self) -> bool { + self.sink.is_terminated() + } +} + +impl<Si, Item, U, St, F> Sink<U> for WithFlatMap<Si, Item, U, St, F> +where + Si: Sink<Item>, + F: FnMut(U) -> St, + St: Stream<Item = Result<Item, Si::Error>>, +{ + type Error = Si::Error; + + fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + self.try_empty_stream(cx) + } + + fn start_send(self: Pin<&mut Self>, item: U) -> Result<(), Self::Error> { + let mut this = self.project(); + + assert!(this.stream.is_none()); + this.stream.set(Some((this.f)(item))); + Ok(()) + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.as_mut().try_empty_stream(cx)?); + self.project().sink.poll_flush(cx) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { + ready!(self.as_mut().try_empty_stream(cx)?); + self.project().sink.poll_close(cx) + } +} diff --git a/third_party/rust/futures-util/src/stream/abortable.rs b/third_party/rust/futures-util/src/stream/abortable.rs new file mode 100644 index 0000000000..1fea895822 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/abortable.rs @@ -0,0 +1,19 @@ +use super::assert_stream; +use crate::stream::{AbortHandle, Abortable}; +use crate::Stream; + +/// Creates a new `Abortable` stream and an `AbortHandle` which can be used to stop it. +/// +/// This function is a convenient (but less flexible) alternative to calling +/// `AbortHandle::new` and `Abortable::new` manually. +/// +/// This function is only available when the `std` or `alloc` feature of this +/// library is activated, and it is activated by default. +pub fn abortable<St>(stream: St) -> (Abortable<St>, AbortHandle) +where + St: Stream, +{ + let (handle, reg) = AbortHandle::new_pair(); + let abortable = assert_stream::<St::Item, _>(Abortable::new(stream, reg)); + (abortable, handle) +} diff --git a/third_party/rust/futures-util/src/stream/empty.rs b/third_party/rust/futures-util/src/stream/empty.rs new file mode 100644 index 0000000000..e4fd87326b --- /dev/null +++ b/third_party/rust/futures-util/src/stream/empty.rs @@ -0,0 +1,45 @@ +use super::assert_stream; +use core::marker::PhantomData; +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; + +/// Stream for the [`empty`] function. +#[derive(Debug)] +#[must_use = "streams do nothing unless polled"] +pub struct Empty<T> { + _phantom: PhantomData<T>, +} + +/// Creates a stream which contains no elements. +/// +/// The returned stream will always return `Ready(None)` when polled. +pub fn empty<T>() -> Empty<T> { + assert_stream::<T, _>(Empty { _phantom: PhantomData }) +} + +impl<T> Unpin for Empty<T> {} + +impl<T> FusedStream for Empty<T> { + fn is_terminated(&self) -> bool { + true + } +} + +impl<T> Stream for Empty<T> { + type Item = T; + + fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<Self::Item>> { + Poll::Ready(None) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + (0, Some(0)) + } +} + +impl<T> Clone for Empty<T> { + fn clone(&self) -> Self { + empty() + } +} diff --git a/third_party/rust/futures-util/src/stream/futures_ordered.rs b/third_party/rust/futures-util/src/stream/futures_ordered.rs new file mode 100644 index 0000000000..618bf1b7bd --- /dev/null +++ b/third_party/rust/futures-util/src/stream/futures_ordered.rs @@ -0,0 +1,244 @@ +use crate::stream::{FuturesUnordered, StreamExt}; +use alloc::collections::binary_heap::{BinaryHeap, PeekMut}; +use core::cmp::Ordering; +use core::fmt::{self, Debug}; +use core::iter::FromIterator; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::{ + task::{Context, Poll}, + FusedStream, +}; +use pin_project_lite::pin_project; + +pin_project! { + #[must_use = "futures do nothing unless you `.await` or poll them"] + #[derive(Debug)] + struct OrderWrapper<T> { + #[pin] + data: T, // A future or a future's output + index: isize, + } +} + +impl<T> PartialEq for OrderWrapper<T> { + fn eq(&self, other: &Self) -> bool { + self.index == other.index + } +} + +impl<T> Eq for OrderWrapper<T> {} + +impl<T> PartialOrd for OrderWrapper<T> { + fn partial_cmp(&self, other: &Self) -> Option<Ordering> { + Some(self.cmp(other)) + } +} + +impl<T> Ord for OrderWrapper<T> { + fn cmp(&self, other: &Self) -> Ordering { + // BinaryHeap is a max heap, so compare backwards here. + other.index.cmp(&self.index) + } +} + +impl<T> Future for OrderWrapper<T> +where + T: Future, +{ + type Output = OrderWrapper<T::Output>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let index = self.index; + self.project().data.poll(cx).map(|output| OrderWrapper { data: output, index }) + } +} + +/// An unbounded queue of futures. +/// +/// This "combinator" is similar to [`FuturesUnordered`], but it imposes a FIFO order +/// on top of the set of futures. While futures in the set will race to +/// completion in parallel, results will only be returned in the order their +/// originating futures were added to the queue. +/// +/// Futures are pushed into this queue and their realized values are yielded in +/// order. This structure is optimized to manage a large number of futures. +/// Futures managed by `FuturesOrdered` will only be polled when they generate +/// notifications. This reduces the required amount of work needed to coordinate +/// large numbers of futures. +/// +/// When a `FuturesOrdered` is first created, it does not contain any futures. +/// Calling `poll` in this state will result in `Poll::Ready(None))` to be +/// returned. Futures are submitted to the queue using `push`; however, the +/// future will **not** be polled at this point. `FuturesOrdered` will only +/// poll managed futures when `FuturesOrdered::poll` is called. As such, it +/// is important to call `poll` after pushing new futures. +/// +/// If `FuturesOrdered::poll` returns `Poll::Ready(None)` this means that +/// the queue is currently not managing any futures. A future may be submitted +/// to the queue at a later time. At that point, a call to +/// `FuturesOrdered::poll` will either return the future's resolved value +/// **or** `Poll::Pending` if the future has not yet completed. When +/// multiple futures are submitted to the queue, `FuturesOrdered::poll` will +/// return `Poll::Pending` until the first future completes, even if +/// some of the later futures have already completed. +/// +/// Note that you can create a ready-made `FuturesOrdered` via the +/// [`collect`](Iterator::collect) method, or you can start with an empty queue +/// with the `FuturesOrdered::new` constructor. +/// +/// This type is only available when the `std` or `alloc` feature of this +/// library is activated, and it is activated by default. +#[must_use = "streams do nothing unless polled"] +pub struct FuturesOrdered<T: Future> { + in_progress_queue: FuturesUnordered<OrderWrapper<T>>, + queued_outputs: BinaryHeap<OrderWrapper<T::Output>>, + next_incoming_index: isize, + next_outgoing_index: isize, +} + +impl<T: Future> Unpin for FuturesOrdered<T> {} + +impl<Fut: Future> FuturesOrdered<Fut> { + /// Constructs a new, empty `FuturesOrdered` + /// + /// The returned `FuturesOrdered` does not contain any futures and, in this + /// state, `FuturesOrdered::poll_next` will return `Poll::Ready(None)`. + pub fn new() -> Self { + Self { + in_progress_queue: FuturesUnordered::new(), + queued_outputs: BinaryHeap::new(), + next_incoming_index: 0, + next_outgoing_index: 0, + } + } + + /// Returns the number of futures contained in the queue. + /// + /// This represents the total number of in-flight futures, both + /// those currently processing and those that have completed but + /// which are waiting for earlier futures to complete. + pub fn len(&self) -> usize { + self.in_progress_queue.len() + self.queued_outputs.len() + } + + /// Returns `true` if the queue contains no futures + pub fn is_empty(&self) -> bool { + self.in_progress_queue.is_empty() && self.queued_outputs.is_empty() + } + + /// Push a future into the queue. + /// + /// This function submits the given future to the internal set for managing. + /// This function will not call `poll` on the submitted future. The caller + /// must ensure that `FuturesOrdered::poll` is called in order to receive + /// task notifications. + #[deprecated(note = "use `push_back` instead")] + pub fn push(&mut self, future: Fut) { + self.push_back(future); + } + + /// Pushes a future to the back of the queue. + /// + /// This function submits the given future to the internal set for managing. + /// This function will not call `poll` on the submitted future. The caller + /// must ensure that `FuturesOrdered::poll` is called in order to receive + /// task notifications. + pub fn push_back(&mut self, future: Fut) { + let wrapped = OrderWrapper { data: future, index: self.next_incoming_index }; + self.next_incoming_index += 1; + self.in_progress_queue.push(wrapped); + } + + /// Pushes a future to the front of the queue. + /// + /// This function submits the given future to the internal set for managing. + /// This function will not call `poll` on the submitted future. The caller + /// must ensure that `FuturesOrdered::poll` is called in order to receive + /// task notifications. This future will be the next future to be returned + /// complete. + pub fn push_front(&mut self, future: Fut) { + let wrapped = OrderWrapper { data: future, index: self.next_outgoing_index - 1 }; + self.next_outgoing_index -= 1; + self.in_progress_queue.push(wrapped); + } +} + +impl<Fut: Future> Default for FuturesOrdered<Fut> { + fn default() -> Self { + Self::new() + } +} + +impl<Fut: Future> Stream for FuturesOrdered<Fut> { + type Item = Fut::Output; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let this = &mut *self; + + // Check to see if we've already received the next value + if let Some(next_output) = this.queued_outputs.peek_mut() { + if next_output.index == this.next_outgoing_index { + this.next_outgoing_index += 1; + return Poll::Ready(Some(PeekMut::pop(next_output).data)); + } + } + + loop { + match ready!(this.in_progress_queue.poll_next_unpin(cx)) { + Some(output) => { + if output.index == this.next_outgoing_index { + this.next_outgoing_index += 1; + return Poll::Ready(Some(output.data)); + } else { + this.queued_outputs.push(output) + } + } + None => return Poll::Ready(None), + } + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let len = self.len(); + (len, Some(len)) + } +} + +impl<Fut: Future> Debug for FuturesOrdered<Fut> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "FuturesOrdered {{ ... }}") + } +} + +impl<Fut: Future> FromIterator<Fut> for FuturesOrdered<Fut> { + fn from_iter<T>(iter: T) -> Self + where + T: IntoIterator<Item = Fut>, + { + let acc = Self::new(); + iter.into_iter().fold(acc, |mut acc, item| { + acc.push_back(item); + acc + }) + } +} + +impl<Fut: Future> FusedStream for FuturesOrdered<Fut> { + fn is_terminated(&self) -> bool { + self.in_progress_queue.is_terminated() && self.queued_outputs.is_empty() + } +} + +impl<Fut: Future> Extend<Fut> for FuturesOrdered<Fut> { + fn extend<I>(&mut self, iter: I) + where + I: IntoIterator<Item = Fut>, + { + for item in iter { + self.push_back(item); + } + } +} diff --git a/third_party/rust/futures-util/src/stream/futures_unordered/abort.rs b/third_party/rust/futures-util/src/stream/futures_unordered/abort.rs new file mode 100644 index 0000000000..1a42d24369 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/futures_unordered/abort.rs @@ -0,0 +1,12 @@ +pub(super) fn abort(s: &str) -> ! { + struct DoublePanic; + + impl Drop for DoublePanic { + fn drop(&mut self) { + panic!("panicking twice to abort the program"); + } + } + + let _bomb = DoublePanic; + panic!("{}", s); +} diff --git a/third_party/rust/futures-util/src/stream/futures_unordered/iter.rs b/third_party/rust/futures-util/src/stream/futures_unordered/iter.rs new file mode 100644 index 0000000000..20248c70fe --- /dev/null +++ b/third_party/rust/futures-util/src/stream/futures_unordered/iter.rs @@ -0,0 +1,172 @@ +use super::task::Task; +use super::FuturesUnordered; +use core::marker::PhantomData; +use core::pin::Pin; +use core::ptr; +use core::sync::atomic::Ordering::Relaxed; + +/// Mutable iterator over all futures in the unordered set. +#[derive(Debug)] +pub struct IterPinMut<'a, Fut> { + pub(super) task: *const Task<Fut>, + pub(super) len: usize, + pub(super) _marker: PhantomData<&'a mut FuturesUnordered<Fut>>, +} + +/// Mutable iterator over all futures in the unordered set. +#[derive(Debug)] +pub struct IterMut<'a, Fut: Unpin>(pub(super) IterPinMut<'a, Fut>); + +/// Immutable iterator over all futures in the unordered set. +#[derive(Debug)] +pub struct IterPinRef<'a, Fut> { + pub(super) task: *const Task<Fut>, + pub(super) len: usize, + pub(super) pending_next_all: *mut Task<Fut>, + pub(super) _marker: PhantomData<&'a FuturesUnordered<Fut>>, +} + +/// Immutable iterator over all the futures in the unordered set. +#[derive(Debug)] +pub struct Iter<'a, Fut: Unpin>(pub(super) IterPinRef<'a, Fut>); + +/// Owned iterator over all futures in the unordered set. +#[derive(Debug)] +pub struct IntoIter<Fut: Unpin> { + pub(super) len: usize, + pub(super) inner: FuturesUnordered<Fut>, +} + +impl<Fut: Unpin> Iterator for IntoIter<Fut> { + type Item = Fut; + + fn next(&mut self) -> Option<Self::Item> { + // `head_all` can be accessed directly and we don't need to spin on + // `Task::next_all` since we have exclusive access to the set. + let task = self.inner.head_all.get_mut(); + + if (*task).is_null() { + return None; + } + + unsafe { + // Moving out of the future is safe because it is `Unpin` + let future = (*(**task).future.get()).take().unwrap(); + + // Mutable access to a previously shared `FuturesUnordered` implies + // that the other threads already released the object before the + // current thread acquired it, so relaxed ordering can be used and + // valid `next_all` checks can be skipped. + let next = (**task).next_all.load(Relaxed); + *task = next; + if !task.is_null() { + *(**task).prev_all.get() = ptr::null_mut(); + } + self.len -= 1; + Some(future) + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + (self.len, Some(self.len)) + } +} + +impl<Fut: Unpin> ExactSizeIterator for IntoIter<Fut> {} + +impl<'a, Fut> Iterator for IterPinMut<'a, Fut> { + type Item = Pin<&'a mut Fut>; + + fn next(&mut self) -> Option<Self::Item> { + if self.task.is_null() { + return None; + } + + unsafe { + let future = (*(*self.task).future.get()).as_mut().unwrap(); + + // Mutable access to a previously shared `FuturesUnordered` implies + // that the other threads already released the object before the + // current thread acquired it, so relaxed ordering can be used and + // valid `next_all` checks can be skipped. + let next = (*self.task).next_all.load(Relaxed); + self.task = next; + self.len -= 1; + Some(Pin::new_unchecked(future)) + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + (self.len, Some(self.len)) + } +} + +impl<Fut> ExactSizeIterator for IterPinMut<'_, Fut> {} + +impl<'a, Fut: Unpin> Iterator for IterMut<'a, Fut> { + type Item = &'a mut Fut; + + fn next(&mut self) -> Option<Self::Item> { + self.0.next().map(Pin::get_mut) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.0.size_hint() + } +} + +impl<Fut: Unpin> ExactSizeIterator for IterMut<'_, Fut> {} + +impl<'a, Fut> Iterator for IterPinRef<'a, Fut> { + type Item = Pin<&'a Fut>; + + fn next(&mut self) -> Option<Self::Item> { + if self.task.is_null() { + return None; + } + + unsafe { + let future = (*(*self.task).future.get()).as_ref().unwrap(); + + // Relaxed ordering can be used since acquire ordering when + // `head_all` was initially read for this iterator implies acquire + // ordering for all previously inserted nodes (and we don't need to + // read `len_all` again for any other nodes). + let next = (*self.task).spin_next_all(self.pending_next_all, Relaxed); + self.task = next; + self.len -= 1; + Some(Pin::new_unchecked(future)) + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + (self.len, Some(self.len)) + } +} + +impl<Fut> ExactSizeIterator for IterPinRef<'_, Fut> {} + +impl<'a, Fut: Unpin> Iterator for Iter<'a, Fut> { + type Item = &'a Fut; + + fn next(&mut self) -> Option<Self::Item> { + self.0.next().map(Pin::get_ref) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.0.size_hint() + } +} + +impl<Fut: Unpin> ExactSizeIterator for Iter<'_, Fut> {} + +// SAFETY: we do nothing thread-local and there is no interior mutability, +// so the usual structural `Send`/`Sync` apply. +unsafe impl<Fut: Send> Send for IterPinRef<'_, Fut> {} +unsafe impl<Fut: Sync> Sync for IterPinRef<'_, Fut> {} + +unsafe impl<Fut: Send> Send for IterPinMut<'_, Fut> {} +unsafe impl<Fut: Sync> Sync for IterPinMut<'_, Fut> {} + +unsafe impl<Fut: Send + Unpin> Send for IntoIter<Fut> {} +unsafe impl<Fut: Sync + Unpin> Sync for IntoIter<Fut> {} diff --git a/third_party/rust/futures-util/src/stream/futures_unordered/mod.rs b/third_party/rust/futures-util/src/stream/futures_unordered/mod.rs new file mode 100644 index 0000000000..6b5804dc41 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/futures_unordered/mod.rs @@ -0,0 +1,661 @@ +//! An unbounded set of futures. +//! +//! This module is only available when the `std` or `alloc` feature of this +//! library is activated, and it is activated by default. + +use crate::task::AtomicWaker; +use alloc::sync::{Arc, Weak}; +use core::cell::UnsafeCell; +use core::fmt::{self, Debug}; +use core::iter::FromIterator; +use core::marker::PhantomData; +use core::mem; +use core::pin::Pin; +use core::ptr; +use core::sync::atomic::Ordering::{AcqRel, Acquire, Relaxed, Release, SeqCst}; +use core::sync::atomic::{AtomicBool, AtomicPtr}; +use futures_core::future::Future; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use futures_task::{FutureObj, LocalFutureObj, LocalSpawn, Spawn, SpawnError}; + +mod abort; + +mod iter; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/102352 +pub use self::iter::{IntoIter, Iter, IterMut, IterPinMut, IterPinRef}; + +mod task; +use self::task::Task; + +mod ready_to_run_queue; +use self::ready_to_run_queue::{Dequeue, ReadyToRunQueue}; + +/// A set of futures which may complete in any order. +/// +/// See [`FuturesOrdered`](crate::stream::FuturesOrdered) for a version of this +/// type that preserves a FIFO order. +/// +/// This structure is optimized to manage a large number of futures. +/// Futures managed by [`FuturesUnordered`] will only be polled when they +/// generate wake-up notifications. This reduces the required amount of work +/// needed to poll large numbers of futures. +/// +/// [`FuturesUnordered`] can be filled by [`collect`](Iterator::collect)ing an +/// iterator of futures into a [`FuturesUnordered`], or by +/// [`push`](FuturesUnordered::push)ing futures onto an existing +/// [`FuturesUnordered`]. When new futures are added, +/// [`poll_next`](Stream::poll_next) must be called in order to begin receiving +/// wake-ups for new futures. +/// +/// Note that you can create a ready-made [`FuturesUnordered`] via the +/// [`collect`](Iterator::collect) method, or you can start with an empty set +/// with the [`FuturesUnordered::new`] constructor. +/// +/// This type is only available when the `std` or `alloc` feature of this +/// library is activated, and it is activated by default. +#[must_use = "streams do nothing unless polled"] +pub struct FuturesUnordered<Fut> { + ready_to_run_queue: Arc<ReadyToRunQueue<Fut>>, + head_all: AtomicPtr<Task<Fut>>, + is_terminated: AtomicBool, +} + +unsafe impl<Fut: Send> Send for FuturesUnordered<Fut> {} +unsafe impl<Fut: Sync> Sync for FuturesUnordered<Fut> {} +impl<Fut> Unpin for FuturesUnordered<Fut> {} + +impl Spawn for FuturesUnordered<FutureObj<'_, ()>> { + fn spawn_obj(&self, future_obj: FutureObj<'static, ()>) -> Result<(), SpawnError> { + self.push(future_obj); + Ok(()) + } +} + +impl LocalSpawn for FuturesUnordered<LocalFutureObj<'_, ()>> { + fn spawn_local_obj(&self, future_obj: LocalFutureObj<'static, ()>) -> Result<(), SpawnError> { + self.push(future_obj); + Ok(()) + } +} + +// FuturesUnordered is implemented using two linked lists. One which links all +// futures managed by a `FuturesUnordered` and one that tracks futures that have +// been scheduled for polling. The first linked list allows for thread safe +// insertion of nodes at the head as well as forward iteration, but is otherwise +// not thread safe and is only accessed by the thread that owns the +// `FuturesUnordered` value for any other operations. The second linked list is +// an implementation of the intrusive MPSC queue algorithm described by +// 1024cores.net. +// +// When a future is submitted to the set, a task is allocated and inserted in +// both linked lists. The next call to `poll_next` will (eventually) see this +// task and call `poll` on the future. +// +// Before a managed future is polled, the current context's waker is replaced +// with one that is aware of the specific future being run. This ensures that +// wake-up notifications generated by that specific future are visible to +// `FuturesUnordered`. When a wake-up notification is received, the task is +// inserted into the ready to run queue, so that its future can be polled later. +// +// Each task is wrapped in an `Arc` and thereby atomically reference counted. +// Also, each task contains an `AtomicBool` which acts as a flag that indicates +// whether the task is currently inserted in the atomic queue. When a wake-up +// notification is received, the task will only be inserted into the ready to +// run queue if it isn't inserted already. + +impl<Fut> Default for FuturesUnordered<Fut> { + fn default() -> Self { + Self::new() + } +} + +impl<Fut> FuturesUnordered<Fut> { + /// Constructs a new, empty [`FuturesUnordered`]. + /// + /// The returned [`FuturesUnordered`] does not contain any futures. + /// In this state, [`FuturesUnordered::poll_next`](Stream::poll_next) will + /// return [`Poll::Ready(None)`](Poll::Ready). + pub fn new() -> Self { + let stub = Arc::new(Task { + future: UnsafeCell::new(None), + next_all: AtomicPtr::new(ptr::null_mut()), + prev_all: UnsafeCell::new(ptr::null()), + len_all: UnsafeCell::new(0), + next_ready_to_run: AtomicPtr::new(ptr::null_mut()), + queued: AtomicBool::new(true), + ready_to_run_queue: Weak::new(), + woken: AtomicBool::new(false), + }); + let stub_ptr = Arc::as_ptr(&stub); + let ready_to_run_queue = Arc::new(ReadyToRunQueue { + waker: AtomicWaker::new(), + head: AtomicPtr::new(stub_ptr as *mut _), + tail: UnsafeCell::new(stub_ptr), + stub, + }); + + Self { + head_all: AtomicPtr::new(ptr::null_mut()), + ready_to_run_queue, + is_terminated: AtomicBool::new(false), + } + } + + /// Returns the number of futures contained in the set. + /// + /// This represents the total number of in-flight futures. + pub fn len(&self) -> usize { + let (_, len) = self.atomic_load_head_and_len_all(); + len + } + + /// Returns `true` if the set contains no futures. + pub fn is_empty(&self) -> bool { + // Relaxed ordering can be used here since we don't need to read from + // the head pointer, only check whether it is null. + self.head_all.load(Relaxed).is_null() + } + + /// Push a future into the set. + /// + /// This method adds the given future to the set. This method will not + /// call [`poll`](core::future::Future::poll) on the submitted future. The caller must + /// ensure that [`FuturesUnordered::poll_next`](Stream::poll_next) is called + /// in order to receive wake-up notifications for the given future. + pub fn push(&self, future: Fut) { + let task = Arc::new(Task { + future: UnsafeCell::new(Some(future)), + next_all: AtomicPtr::new(self.pending_next_all()), + prev_all: UnsafeCell::new(ptr::null_mut()), + len_all: UnsafeCell::new(0), + next_ready_to_run: AtomicPtr::new(ptr::null_mut()), + queued: AtomicBool::new(true), + ready_to_run_queue: Arc::downgrade(&self.ready_to_run_queue), + woken: AtomicBool::new(false), + }); + + // Reset the `is_terminated` flag if we've previously marked ourselves + // as terminated. + self.is_terminated.store(false, Relaxed); + + // Right now our task has a strong reference count of 1. We transfer + // ownership of this reference count to our internal linked list + // and we'll reclaim ownership through the `unlink` method below. + let ptr = self.link(task); + + // We'll need to get the future "into the system" to start tracking it, + // e.g. getting its wake-up notifications going to us tracking which + // futures are ready. To do that we unconditionally enqueue it for + // polling here. + self.ready_to_run_queue.enqueue(ptr); + } + + /// Returns an iterator that allows inspecting each future in the set. + pub fn iter(&self) -> Iter<'_, Fut> + where + Fut: Unpin, + { + Iter(Pin::new(self).iter_pin_ref()) + } + + /// Returns an iterator that allows inspecting each future in the set. + pub fn iter_pin_ref(self: Pin<&Self>) -> IterPinRef<'_, Fut> { + let (task, len) = self.atomic_load_head_and_len_all(); + let pending_next_all = self.pending_next_all(); + + IterPinRef { task, len, pending_next_all, _marker: PhantomData } + } + + /// Returns an iterator that allows modifying each future in the set. + pub fn iter_mut(&mut self) -> IterMut<'_, Fut> + where + Fut: Unpin, + { + IterMut(Pin::new(self).iter_pin_mut()) + } + + /// Returns an iterator that allows modifying each future in the set. + pub fn iter_pin_mut(mut self: Pin<&mut Self>) -> IterPinMut<'_, Fut> { + // `head_all` can be accessed directly and we don't need to spin on + // `Task::next_all` since we have exclusive access to the set. + let task = *self.head_all.get_mut(); + let len = if task.is_null() { 0 } else { unsafe { *(*task).len_all.get() } }; + + IterPinMut { task, len, _marker: PhantomData } + } + + /// Returns the current head node and number of futures in the list of all + /// futures within a context where access is shared with other threads + /// (mostly for use with the `len` and `iter_pin_ref` methods). + fn atomic_load_head_and_len_all(&self) -> (*const Task<Fut>, usize) { + let task = self.head_all.load(Acquire); + let len = if task.is_null() { + 0 + } else { + unsafe { + (*task).spin_next_all(self.pending_next_all(), Acquire); + *(*task).len_all.get() + } + }; + + (task, len) + } + + /// Releases the task. It destroys the future inside and either drops + /// the `Arc<Task>` or transfers ownership to the ready to run queue. + /// The task this method is called on must have been unlinked before. + fn release_task(&mut self, task: Arc<Task<Fut>>) { + // `release_task` must only be called on unlinked tasks + debug_assert_eq!(task.next_all.load(Relaxed), self.pending_next_all()); + unsafe { + debug_assert!((*task.prev_all.get()).is_null()); + } + + // The future is done, try to reset the queued flag. This will prevent + // `wake` from doing any work in the future + let prev = task.queued.swap(true, SeqCst); + + // Drop the future, even if it hasn't finished yet. This is safe + // because we're dropping the future on the thread that owns + // `FuturesUnordered`, which correctly tracks `Fut`'s lifetimes and + // such. + unsafe { + // Set to `None` rather than `take()`ing to prevent moving the + // future. + *task.future.get() = None; + } + + // If the queued flag was previously set, then it means that this task + // is still in our internal ready to run queue. We then transfer + // ownership of our reference count to the ready to run queue, and it'll + // come along and free it later, noticing that the future is `None`. + // + // If, however, the queued flag was *not* set then we're safe to + // release our reference count on the task. The queued flag was set + // above so all future `enqueue` operations will not actually + // enqueue the task, so our task will never see the ready to run queue + // again. The task itself will be deallocated once all reference counts + // have been dropped elsewhere by the various wakers that contain it. + if prev { + mem::forget(task); + } + } + + /// Insert a new task into the internal linked list. + fn link(&self, task: Arc<Task<Fut>>) -> *const Task<Fut> { + // `next_all` should already be reset to the pending state before this + // function is called. + debug_assert_eq!(task.next_all.load(Relaxed), self.pending_next_all()); + let ptr = Arc::into_raw(task); + + // Atomically swap out the old head node to get the node that should be + // assigned to `next_all`. + let next = self.head_all.swap(ptr as *mut _, AcqRel); + + unsafe { + // Store the new list length in the new node. + let new_len = if next.is_null() { + 1 + } else { + // Make sure `next_all` has been written to signal that it is + // safe to read `len_all`. + (*next).spin_next_all(self.pending_next_all(), Acquire); + *(*next).len_all.get() + 1 + }; + *(*ptr).len_all.get() = new_len; + + // Write the old head as the next node pointer, signaling to other + // threads that `len_all` and `next_all` are ready to read. + (*ptr).next_all.store(next, Release); + + // `prev_all` updates don't need to be synchronized, as the field is + // only ever used after exclusive access has been acquired. + if !next.is_null() { + *(*next).prev_all.get() = ptr; + } + } + + ptr + } + + /// Remove the task from the linked list tracking all tasks currently + /// managed by `FuturesUnordered`. + /// This method is unsafe because it has be guaranteed that `task` is a + /// valid pointer. + unsafe fn unlink(&mut self, task: *const Task<Fut>) -> Arc<Task<Fut>> { + // Compute the new list length now in case we're removing the head node + // and won't be able to retrieve the correct length later. + let head = *self.head_all.get_mut(); + debug_assert!(!head.is_null()); + let new_len = *(*head).len_all.get() - 1; + + let task = Arc::from_raw(task); + let next = task.next_all.load(Relaxed); + let prev = *task.prev_all.get(); + task.next_all.store(self.pending_next_all(), Relaxed); + *task.prev_all.get() = ptr::null_mut(); + + if !next.is_null() { + *(*next).prev_all.get() = prev; + } + + if !prev.is_null() { + (*prev).next_all.store(next, Relaxed); + } else { + *self.head_all.get_mut() = next; + } + + // Store the new list length in the head node. + let head = *self.head_all.get_mut(); + if !head.is_null() { + *(*head).len_all.get() = new_len; + } + + task + } + + /// Returns the reserved value for `Task::next_all` to indicate a pending + /// assignment from the thread that inserted the task. + /// + /// `FuturesUnordered::link` needs to update `Task` pointers in an order + /// that ensures any iterators created on other threads can correctly + /// traverse the entire `Task` list using the chain of `next_all` pointers. + /// This could be solved with a compare-exchange loop that stores the + /// current `head_all` in `next_all` and swaps out `head_all` with the new + /// `Task` pointer if the head hasn't already changed. Under heavy thread + /// contention, this compare-exchange loop could become costly. + /// + /// An alternative is to initialize `next_all` to a reserved pending state + /// first, perform an atomic swap on `head_all`, and finally update + /// `next_all` with the old head node. Iterators will then either see the + /// pending state value or the correct next node pointer, and can reload + /// `next_all` as needed until the correct value is loaded. The number of + /// retries needed (if any) would be small and will always be finite, so + /// this should generally perform better than the compare-exchange loop. + /// + /// A valid `Task` pointer in the `head_all` list is guaranteed to never be + /// this value, so it is safe to use as a reserved value until the correct + /// value can be written. + fn pending_next_all(&self) -> *mut Task<Fut> { + // The `ReadyToRunQueue` stub is never inserted into the `head_all` + // list, and its pointer value will remain valid for the lifetime of + // this `FuturesUnordered`, so we can make use of its value here. + Arc::as_ptr(&self.ready_to_run_queue.stub) as *mut _ + } +} + +impl<Fut: Future> Stream for FuturesUnordered<Fut> { + type Item = Fut::Output; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let len = self.len(); + + // Keep track of how many child futures we have polled, + // in case we want to forcibly yield. + let mut polled = 0; + let mut yielded = 0; + + // Ensure `parent` is correctly set. + self.ready_to_run_queue.waker.register(cx.waker()); + + loop { + // Safety: &mut self guarantees the mutual exclusion `dequeue` + // expects + let task = match unsafe { self.ready_to_run_queue.dequeue() } { + Dequeue::Empty => { + if self.is_empty() { + // We can only consider ourselves terminated once we + // have yielded a `None` + *self.is_terminated.get_mut() = true; + return Poll::Ready(None); + } else { + return Poll::Pending; + } + } + Dequeue::Inconsistent => { + // At this point, it may be worth yielding the thread & + // spinning a few times... but for now, just yield using the + // task system. + cx.waker().wake_by_ref(); + return Poll::Pending; + } + Dequeue::Data(task) => task, + }; + + debug_assert!(task != self.ready_to_run_queue.stub()); + + // Safety: + // - `task` is a valid pointer. + // - We are the only thread that accesses the `UnsafeCell` that + // contains the future + let future = match unsafe { &mut *(*task).future.get() } { + Some(future) => future, + + // If the future has already gone away then we're just + // cleaning out this task. See the comment in + // `release_task` for more information, but we're basically + // just taking ownership of our reference count here. + None => { + // This case only happens when `release_task` was called + // for this task before and couldn't drop the task + // because it was already enqueued in the ready to run + // queue. + + // Safety: `task` is a valid pointer + let task = unsafe { Arc::from_raw(task) }; + + // Double check that the call to `release_task` really + // happened. Calling it required the task to be unlinked. + debug_assert_eq!(task.next_all.load(Relaxed), self.pending_next_all()); + unsafe { + debug_assert!((*task.prev_all.get()).is_null()); + } + continue; + } + }; + + // Safety: `task` is a valid pointer + let task = unsafe { self.unlink(task) }; + + // Unset queued flag: This must be done before polling to ensure + // that the future's task gets rescheduled if it sends a wake-up + // notification **during** the call to `poll`. + let prev = task.queued.swap(false, SeqCst); + assert!(prev); + + // We're going to need to be very careful if the `poll` + // method below panics. We need to (a) not leak memory and + // (b) ensure that we still don't have any use-after-frees. To + // manage this we do a few things: + // + // * A "bomb" is created which if dropped abnormally will call + // `release_task`. That way we'll be sure the memory management + // of the `task` is managed correctly. In particular + // `release_task` will drop the future. This ensures that it is + // dropped on this thread and not accidentally on a different + // thread (bad). + // * We unlink the task from our internal queue to preemptively + // assume it'll panic, in which case we'll want to discard it + // regardless. + struct Bomb<'a, Fut> { + queue: &'a mut FuturesUnordered<Fut>, + task: Option<Arc<Task<Fut>>>, + } + + impl<Fut> Drop for Bomb<'_, Fut> { + fn drop(&mut self) { + if let Some(task) = self.task.take() { + self.queue.release_task(task); + } + } + } + + let mut bomb = Bomb { task: Some(task), queue: &mut *self }; + + // Poll the underlying future with the appropriate waker + // implementation. This is where a large bit of the unsafety + // starts to stem from internally. The waker is basically just + // our `Arc<Task<Fut>>` and can schedule the future for polling by + // enqueuing itself in the ready to run queue. + // + // Critically though `Task<Fut>` won't actually access `Fut`, the + // future, while it's floating around inside of wakers. + // These structs will basically just use `Fut` to size + // the internal allocation, appropriately accessing fields and + // deallocating the task if need be. + let res = { + let task = bomb.task.as_ref().unwrap(); + // We are only interested in whether the future is awoken before it + // finishes polling, so reset the flag here. + task.woken.store(false, Relaxed); + let waker = Task::waker_ref(task); + let mut cx = Context::from_waker(&waker); + + // Safety: We won't move the future ever again + let future = unsafe { Pin::new_unchecked(future) }; + + future.poll(&mut cx) + }; + polled += 1; + + match res { + Poll::Pending => { + let task = bomb.task.take().unwrap(); + // If the future was awoken during polling, we assume + // the future wanted to explicitly yield. + yielded += task.woken.load(Relaxed) as usize; + bomb.queue.link(task); + + // If a future yields, we respect it and yield here. + // If all futures have been polled, we also yield here to + // avoid starving other tasks waiting on the executor. + // (polling the same future twice per iteration may cause + // the problem: https://github.com/rust-lang/futures-rs/pull/2333) + if yielded >= 2 || polled == len { + cx.waker().wake_by_ref(); + return Poll::Pending; + } + continue; + } + Poll::Ready(output) => return Poll::Ready(Some(output)), + } + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let len = self.len(); + (len, Some(len)) + } +} + +impl<Fut> Debug for FuturesUnordered<Fut> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "FuturesUnordered {{ ... }}") + } +} + +impl<Fut> FuturesUnordered<Fut> { + /// Clears the set, removing all futures. + pub fn clear(&mut self) { + self.clear_head_all(); + + // we just cleared all the tasks, and we have &mut self, so this is safe. + unsafe { self.ready_to_run_queue.clear() }; + + self.is_terminated.store(false, Relaxed); + } + + fn clear_head_all(&mut self) { + while !self.head_all.get_mut().is_null() { + let head = *self.head_all.get_mut(); + let task = unsafe { self.unlink(head) }; + self.release_task(task); + } + } +} + +impl<Fut> Drop for FuturesUnordered<Fut> { + fn drop(&mut self) { + // When a `FuturesUnordered` is dropped we want to drop all futures + // associated with it. At the same time though there may be tons of + // wakers flying around which contain `Task<Fut>` references + // inside them. We'll let those naturally get deallocated. + self.clear_head_all(); + + // Note that at this point we could still have a bunch of tasks in the + // ready to run queue. None of those tasks, however, have futures + // associated with them so they're safe to destroy on any thread. At + // this point the `FuturesUnordered` struct, the owner of the one strong + // reference to the ready to run queue will drop the strong reference. + // At that point whichever thread releases the strong refcount last (be + // it this thread or some other thread as part of an `upgrade`) will + // clear out the ready to run queue and free all remaining tasks. + // + // While that freeing operation isn't guaranteed to happen here, it's + // guaranteed to happen "promptly" as no more "blocking work" will + // happen while there's a strong refcount held. + } +} + +impl<'a, Fut: Unpin> IntoIterator for &'a FuturesUnordered<Fut> { + type Item = &'a Fut; + type IntoIter = Iter<'a, Fut>; + + fn into_iter(self) -> Self::IntoIter { + self.iter() + } +} + +impl<'a, Fut: Unpin> IntoIterator for &'a mut FuturesUnordered<Fut> { + type Item = &'a mut Fut; + type IntoIter = IterMut<'a, Fut>; + + fn into_iter(self) -> Self::IntoIter { + self.iter_mut() + } +} + +impl<Fut: Unpin> IntoIterator for FuturesUnordered<Fut> { + type Item = Fut; + type IntoIter = IntoIter<Fut>; + + fn into_iter(mut self) -> Self::IntoIter { + // `head_all` can be accessed directly and we don't need to spin on + // `Task::next_all` since we have exclusive access to the set. + let task = *self.head_all.get_mut(); + let len = if task.is_null() { 0 } else { unsafe { *(*task).len_all.get() } }; + + IntoIter { len, inner: self } + } +} + +impl<Fut> FromIterator<Fut> for FuturesUnordered<Fut> { + fn from_iter<I>(iter: I) -> Self + where + I: IntoIterator<Item = Fut>, + { + let acc = Self::new(); + iter.into_iter().fold(acc, |acc, item| { + acc.push(item); + acc + }) + } +} + +impl<Fut: Future> FusedStream for FuturesUnordered<Fut> { + fn is_terminated(&self) -> bool { + self.is_terminated.load(Relaxed) + } +} + +impl<Fut> Extend<Fut> for FuturesUnordered<Fut> { + fn extend<I>(&mut self, iter: I) + where + I: IntoIterator<Item = Fut>, + { + for item in iter { + self.push(item); + } + } +} diff --git a/third_party/rust/futures-util/src/stream/futures_unordered/ready_to_run_queue.rs b/third_party/rust/futures-util/src/stream/futures_unordered/ready_to_run_queue.rs new file mode 100644 index 0000000000..4518705320 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/futures_unordered/ready_to_run_queue.rs @@ -0,0 +1,122 @@ +use crate::task::AtomicWaker; +use alloc::sync::Arc; +use core::cell::UnsafeCell; +use core::ptr; +use core::sync::atomic::AtomicPtr; +use core::sync::atomic::Ordering::{AcqRel, Acquire, Relaxed, Release}; + +use super::abort::abort; +use super::task::Task; + +pub(super) enum Dequeue<Fut> { + Data(*const Task<Fut>), + Empty, + Inconsistent, +} + +pub(super) struct ReadyToRunQueue<Fut> { + // The waker of the task using `FuturesUnordered`. + pub(super) waker: AtomicWaker, + + // Head/tail of the readiness queue + pub(super) head: AtomicPtr<Task<Fut>>, + pub(super) tail: UnsafeCell<*const Task<Fut>>, + pub(super) stub: Arc<Task<Fut>>, +} + +/// An MPSC queue into which the tasks containing the futures are inserted +/// whenever the future inside is scheduled for polling. +impl<Fut> ReadyToRunQueue<Fut> { + /// The enqueue function from the 1024cores intrusive MPSC queue algorithm. + pub(super) fn enqueue(&self, task: *const Task<Fut>) { + unsafe { + debug_assert!((*task).queued.load(Relaxed)); + + // This action does not require any coordination + (*task).next_ready_to_run.store(ptr::null_mut(), Relaxed); + + // Note that these atomic orderings come from 1024cores + let task = task as *mut _; + let prev = self.head.swap(task, AcqRel); + (*prev).next_ready_to_run.store(task, Release); + } + } + + /// The dequeue function from the 1024cores intrusive MPSC queue algorithm + /// + /// Note that this is unsafe as it required mutual exclusion (only one + /// thread can call this) to be guaranteed elsewhere. + pub(super) unsafe fn dequeue(&self) -> Dequeue<Fut> { + let mut tail = *self.tail.get(); + let mut next = (*tail).next_ready_to_run.load(Acquire); + + if tail == self.stub() { + if next.is_null() { + return Dequeue::Empty; + } + + *self.tail.get() = next; + tail = next; + next = (*next).next_ready_to_run.load(Acquire); + } + + if !next.is_null() { + *self.tail.get() = next; + debug_assert!(tail != self.stub()); + return Dequeue::Data(tail); + } + + if self.head.load(Acquire) as *const _ != tail { + return Dequeue::Inconsistent; + } + + self.enqueue(self.stub()); + + next = (*tail).next_ready_to_run.load(Acquire); + + if !next.is_null() { + *self.tail.get() = next; + return Dequeue::Data(tail); + } + + Dequeue::Inconsistent + } + + pub(super) fn stub(&self) -> *const Task<Fut> { + Arc::as_ptr(&self.stub) + } + + // Clear the queue of tasks. + // + // Note that each task has a strong reference count associated with it + // which is owned by the ready to run queue. This method just pulls out + // tasks and drops their refcounts. + // + // # Safety + // + // - All tasks **must** have had their futures dropped already (by FuturesUnordered::clear) + // - The caller **must** guarantee unique access to `self` + pub(crate) unsafe fn clear(&self) { + loop { + // SAFETY: We have the guarantee of mutual exclusion required by `dequeue`. + match self.dequeue() { + Dequeue::Empty => break, + Dequeue::Inconsistent => abort("inconsistent in drop"), + Dequeue::Data(ptr) => drop(Arc::from_raw(ptr)), + } + } + } +} + +impl<Fut> Drop for ReadyToRunQueue<Fut> { + fn drop(&mut self) { + // Once we're in the destructor for `Inner<Fut>` we need to clear out + // the ready to run queue of tasks if there's anything left in there. + + // All tasks have had their futures dropped already by the `FuturesUnordered` + // destructor above, and we have &mut self, so this is safe. + unsafe { + self.clear(); + } + } +} diff --git a/third_party/rust/futures-util/src/stream/futures_unordered/task.rs b/third_party/rust/futures-util/src/stream/futures_unordered/task.rs new file mode 100644 index 0000000000..ec2114effa --- /dev/null +++ b/third_party/rust/futures-util/src/stream/futures_unordered/task.rs @@ -0,0 +1,125 @@ +use alloc::sync::{Arc, Weak}; +use core::cell::UnsafeCell; +use core::sync::atomic::Ordering::{self, Relaxed, SeqCst}; +use core::sync::atomic::{AtomicBool, AtomicPtr}; + +use super::abort::abort; +use super::ReadyToRunQueue; +use crate::task::{waker_ref, ArcWake, WakerRef}; + +pub(super) struct Task<Fut> { + // The future + pub(super) future: UnsafeCell<Option<Fut>>, + + // Next pointer for linked list tracking all active tasks (use + // `spin_next_all` to read when access is shared across threads) + pub(super) next_all: AtomicPtr<Task<Fut>>, + + // Previous task in linked list tracking all active tasks + pub(super) prev_all: UnsafeCell<*const Task<Fut>>, + + // Length of the linked list tracking all active tasks when this node was + // inserted (use `spin_next_all` to synchronize before reading when access + // is shared across threads) + pub(super) len_all: UnsafeCell<usize>, + + // Next pointer in ready to run queue + pub(super) next_ready_to_run: AtomicPtr<Task<Fut>>, + + // Queue that we'll be enqueued to when woken + pub(super) ready_to_run_queue: Weak<ReadyToRunQueue<Fut>>, + + // Whether or not this task is currently in the ready to run queue + pub(super) queued: AtomicBool, + + // Whether the future was awoken during polling + // It is possible for this flag to be set to true after the polling, + // but it will be ignored. + pub(super) woken: AtomicBool, +} + +// `Task` can be sent across threads safely because it ensures that +// the underlying `Fut` type isn't touched from any of its methods. +// +// The parent (`super`) module is trusted not to access `future` +// across different threads. +unsafe impl<Fut> Send for Task<Fut> {} +unsafe impl<Fut> Sync for Task<Fut> {} + +impl<Fut> ArcWake for Task<Fut> { + fn wake_by_ref(arc_self: &Arc<Self>) { + let inner = match arc_self.ready_to_run_queue.upgrade() { + Some(inner) => inner, + None => return, + }; + + arc_self.woken.store(true, Relaxed); + + // It's our job to enqueue this task it into the ready to run queue. To + // do this we set the `queued` flag, and if successful we then do the + // actual queueing operation, ensuring that we're only queued once. + // + // Once the task is inserted call `wake` to notify the parent task, + // as it'll want to come along and run our task later. + // + // Note that we don't change the reference count of the task here, + // we merely enqueue the raw pointer. The `FuturesUnordered` + // implementation guarantees that if we set the `queued` flag that + // there's a reference count held by the main `FuturesUnordered` queue + // still. + let prev = arc_self.queued.swap(true, SeqCst); + if !prev { + inner.enqueue(Arc::as_ptr(arc_self)); + inner.waker.wake(); + } + } +} + +impl<Fut> Task<Fut> { + /// Returns a waker reference for this task without cloning the Arc. + pub(super) fn waker_ref(this: &Arc<Self>) -> WakerRef<'_> { + waker_ref(this) + } + + /// Spins until `next_all` is no longer set to `pending_next_all`. + /// + /// The temporary `pending_next_all` value is typically overwritten fairly + /// quickly after a node is inserted into the list of all futures, so this + /// should rarely spin much. + /// + /// When it returns, the correct `next_all` value is returned. + /// + /// `Relaxed` or `Acquire` ordering can be used. `Acquire` ordering must be + /// used before `len_all` can be safely read. + #[inline] + pub(super) fn spin_next_all( + &self, + pending_next_all: *mut Self, + ordering: Ordering, + ) -> *const Self { + loop { + let next = self.next_all.load(ordering); + if next != pending_next_all { + return next; + } + } + } +} + +impl<Fut> Drop for Task<Fut> { + fn drop(&mut self) { + // Since `Task<Fut>` is sent across all threads for any lifetime, + // regardless of `Fut`, we, to guarantee memory safety, can't actually + // touch `Fut` at any time except when we have a reference to the + // `FuturesUnordered` itself . + // + // Consequently it *should* be the case that we always drop futures from + // the `FuturesUnordered` instance. This is a bomb, just in case there's + // a bug in that logic. + unsafe { + if (*self.future.get()).is_some() { + abort("future still here when dropping"); + } + } + } +} diff --git a/third_party/rust/futures-util/src/stream/iter.rs b/third_party/rust/futures-util/src/stream/iter.rs new file mode 100644 index 0000000000..20471c2ed0 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/iter.rs @@ -0,0 +1,49 @@ +use super::assert_stream; +use core::pin::Pin; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; + +/// Stream for the [`iter`] function. +#[derive(Debug, Clone)] +#[must_use = "streams do nothing unless polled"] +pub struct Iter<I> { + iter: I, +} + +impl<I> Unpin for Iter<I> {} + +/// Converts an `Iterator` into a `Stream` which is always ready +/// to yield the next value. +/// +/// Iterators in Rust don't express the ability to block, so this adapter +/// simply always calls `iter.next()` and returns that. +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::stream::{self, StreamExt}; +/// +/// let stream = stream::iter(vec![17, 19]); +/// assert_eq!(vec![17, 19], stream.collect::<Vec<i32>>().await); +/// # }); +/// ``` +pub fn iter<I>(i: I) -> Iter<I::IntoIter> +where + I: IntoIterator, +{ + assert_stream::<I::Item, _>(Iter { iter: i.into_iter() }) +} + +impl<I> Stream for Iter<I> +where + I: Iterator, +{ + type Item = I::Item; + + fn poll_next(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<I::Item>> { + Poll::Ready(self.iter.next()) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.iter.size_hint() + } +} diff --git a/third_party/rust/futures-util/src/stream/mod.rs b/third_party/rust/futures-util/src/stream/mod.rs new file mode 100644 index 0000000000..ec685b9848 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/mod.rs @@ -0,0 +1,143 @@ +//! Asynchronous streams. +//! +//! This module contains: +//! +//! - The [`Stream`] trait, for objects that can asynchronously produce a +//! sequence of values. +//! - The [`StreamExt`] and [`TryStreamExt`] trait, which provides adapters for +//! chaining and composing streams. +//! - Top-level stream constructors like [`iter`](iter()) which creates a +//! stream from an iterator. + +#[cfg(feature = "alloc")] +pub use futures_core::stream::{BoxStream, LocalBoxStream}; +pub use futures_core::stream::{FusedStream, Stream, TryStream}; + +// Extension traits and combinators + +#[allow(clippy::module_inception)] +mod stream; +pub use self::stream::{ + Chain, Collect, Concat, Cycle, Enumerate, Filter, FilterMap, FlatMap, Flatten, Fold, ForEach, + Fuse, Inspect, Map, Next, NextIf, NextIfEq, Peek, PeekMut, Peekable, Scan, SelectNextSome, + Skip, SkipWhile, StreamExt, StreamFuture, Take, TakeUntil, TakeWhile, Then, Unzip, Zip, +}; + +#[cfg(feature = "std")] +pub use self::stream::CatchUnwind; + +#[cfg(feature = "alloc")] +pub use self::stream::Chunks; + +#[cfg(feature = "alloc")] +pub use self::stream::ReadyChunks; + +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub use self::stream::Forward; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use self::stream::{BufferUnordered, Buffered, ForEachConcurrent}; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +#[cfg(feature = "alloc")] +pub use self::stream::{ReuniteError, SplitSink, SplitStream}; + +mod try_stream; +pub use self::try_stream::{ + try_unfold, AndThen, ErrInto, InspectErr, InspectOk, IntoStream, MapErr, MapOk, OrElse, + TryCollect, TryConcat, TryFilter, TryFilterMap, TryFlatten, TryFold, TryForEach, TryNext, + TrySkipWhile, TryStreamExt, TryTakeWhile, TryUnfold, +}; + +#[cfg(feature = "io")] +#[cfg_attr(docsrs, doc(cfg(feature = "io")))] +#[cfg(feature = "std")] +pub use self::try_stream::IntoAsyncRead; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use self::try_stream::{TryBufferUnordered, TryBuffered, TryForEachConcurrent}; + +#[cfg(feature = "alloc")] +pub use self::try_stream::{TryChunks, TryChunksError}; + +// Primitive streams + +mod iter; +pub use self::iter::{iter, Iter}; + +mod repeat; +pub use self::repeat::{repeat, Repeat}; + +mod repeat_with; +pub use self::repeat_with::{repeat_with, RepeatWith}; + +mod empty; +pub use self::empty::{empty, Empty}; + +mod once; +pub use self::once::{once, Once}; + +mod pending; +pub use self::pending::{pending, Pending}; + +mod poll_fn; +pub use self::poll_fn::{poll_fn, PollFn}; + +mod poll_immediate; +pub use self::poll_immediate::{poll_immediate, PollImmediate}; + +mod select; +pub use self::select::{select, Select}; + +mod select_with_strategy; +pub use self::select_with_strategy::{select_with_strategy, PollNext, SelectWithStrategy}; + +mod unfold; +pub use self::unfold::{unfold, Unfold}; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod futures_ordered; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use self::futures_ordered::FuturesOrdered; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub mod futures_unordered; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +#[doc(inline)] +pub use self::futures_unordered::FuturesUnordered; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub mod select_all; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +#[doc(inline)] +pub use self::select_all::{select_all, SelectAll}; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod abortable; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use crate::abortable::{AbortHandle, AbortRegistration, Abortable, Aborted}; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use abortable::abortable; + +// Just a helper function to ensure the streams we're returning all have the +// right implementations. +pub(crate) fn assert_stream<T, S>(stream: S) -> S +where + S: Stream<Item = T>, +{ + stream +} diff --git a/third_party/rust/futures-util/src/stream/once.rs b/third_party/rust/futures-util/src/stream/once.rs new file mode 100644 index 0000000000..ee21c8b594 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/once.rs @@ -0,0 +1,67 @@ +use super::assert_stream; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +/// Creates a stream of a single element. +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::stream::{self, StreamExt}; +/// +/// let stream = stream::once(async { 17 }); +/// let collected = stream.collect::<Vec<i32>>().await; +/// assert_eq!(collected, vec![17]); +/// # }); +/// ``` +pub fn once<Fut: Future>(future: Fut) -> Once<Fut> { + assert_stream::<Fut::Output, _>(Once::new(future)) +} + +pin_project! { + /// A stream which emits single element and then EOF. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Once<Fut> { + #[pin] + future: Option<Fut> + } +} + +impl<Fut> Once<Fut> { + pub(crate) fn new(future: Fut) -> Self { + Self { future: Some(future) } + } +} + +impl<Fut: Future> Stream for Once<Fut> { + type Item = Fut::Output; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + let v = match this.future.as_mut().as_pin_mut() { + Some(fut) => ready!(fut.poll(cx)), + None => return Poll::Ready(None), + }; + + this.future.set(None); + Poll::Ready(Some(v)) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.future.is_some() { + (1, Some(1)) + } else { + (0, Some(0)) + } + } +} + +impl<Fut: Future> FusedStream for Once<Fut> { + fn is_terminated(&self) -> bool { + self.future.is_none() + } +} diff --git a/third_party/rust/futures-util/src/stream/pending.rs b/third_party/rust/futures-util/src/stream/pending.rs new file mode 100644 index 0000000000..d7030ff3cc --- /dev/null +++ b/third_party/rust/futures-util/src/stream/pending.rs @@ -0,0 +1,45 @@ +use super::assert_stream; +use core::marker; +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; + +/// Stream for the [`pending()`] function. +#[derive(Debug)] +#[must_use = "streams do nothing unless polled"] +pub struct Pending<T> { + _data: marker::PhantomData<T>, +} + +/// Creates a stream which never returns any elements. +/// +/// The returned stream will always return `Pending` when polled. +pub fn pending<T>() -> Pending<T> { + assert_stream::<T, _>(Pending { _data: marker::PhantomData }) +} + +impl<T> Unpin for Pending<T> {} + +impl<T> FusedStream for Pending<T> { + fn is_terminated(&self) -> bool { + true + } +} + +impl<T> Stream for Pending<T> { + type Item = T; + + fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<Self::Item>> { + Poll::Pending + } + + fn size_hint(&self) -> (usize, Option<usize>) { + (0, Some(0)) + } +} + +impl<T> Clone for Pending<T> { + fn clone(&self) -> Self { + pending() + } +} diff --git a/third_party/rust/futures-util/src/stream/poll_fn.rs b/third_party/rust/futures-util/src/stream/poll_fn.rs new file mode 100644 index 0000000000..b9bd7d1664 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/poll_fn.rs @@ -0,0 +1,57 @@ +//! Definition of the `PollFn` combinator + +use super::assert_stream; +use core::fmt; +use core::pin::Pin; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; + +/// Stream for the [`poll_fn`] function. +#[must_use = "streams do nothing unless polled"] +pub struct PollFn<F> { + f: F, +} + +impl<F> Unpin for PollFn<F> {} + +impl<F> fmt::Debug for PollFn<F> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("PollFn").finish() + } +} + +/// Creates a new stream wrapping a function returning `Poll<Option<T>>`. +/// +/// Polling the returned stream calls the wrapped function. +/// +/// # Examples +/// +/// ``` +/// use futures::stream::poll_fn; +/// use futures::task::Poll; +/// +/// let mut counter = 1usize; +/// +/// let read_stream = poll_fn(move |_| -> Poll<Option<String>> { +/// if counter == 0 { return Poll::Ready(None); } +/// counter -= 1; +/// Poll::Ready(Some("Hello, World!".to_owned())) +/// }); +/// ``` +pub fn poll_fn<T, F>(f: F) -> PollFn<F> +where + F: FnMut(&mut Context<'_>) -> Poll<Option<T>>, +{ + assert_stream::<T, _>(PollFn { f }) +} + +impl<T, F> Stream for PollFn<F> +where + F: FnMut(&mut Context<'_>) -> Poll<Option<T>>, +{ + type Item = T; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T>> { + (&mut self.f)(cx) + } +} diff --git a/third_party/rust/futures-util/src/stream/poll_immediate.rs b/third_party/rust/futures-util/src/stream/poll_immediate.rs new file mode 100644 index 0000000000..c7e8a5b3c6 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/poll_immediate.rs @@ -0,0 +1,80 @@ +use core::pin::Pin; +use futures_core::task::{Context, Poll}; +use futures_core::Stream; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [poll_immediate](poll_immediate()) function. + /// + /// It will never return [Poll::Pending](core::task::Poll::Pending) + #[derive(Debug, Clone)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct PollImmediate<S> { + #[pin] + stream: Option<S> + } +} + +impl<T, S> Stream for PollImmediate<S> +where + S: Stream<Item = T>, +{ + type Item = Poll<T>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + let stream = match this.stream.as_mut().as_pin_mut() { + // inner is gone, so we can continue to signal that the stream is closed. + None => return Poll::Ready(None), + Some(inner) => inner, + }; + + match stream.poll_next(cx) { + Poll::Ready(Some(t)) => Poll::Ready(Some(Poll::Ready(t))), + Poll::Ready(None) => { + this.stream.set(None); + Poll::Ready(None) + } + Poll::Pending => Poll::Ready(Some(Poll::Pending)), + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.stream.as_ref().map_or((0, Some(0)), Stream::size_hint) + } +} + +impl<S: Stream> super::FusedStream for PollImmediate<S> { + fn is_terminated(&self) -> bool { + self.stream.is_none() + } +} + +/// Creates a new stream that always immediately returns [Poll::Ready](core::task::Poll::Ready) when awaiting it. +/// +/// This is useful when immediacy is more important than waiting for the next item to be ready. +/// +/// # Examples +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::stream::{self, StreamExt}; +/// use futures::task::Poll; +/// +/// let mut r = stream::poll_immediate(Box::pin(stream::iter(1_u32..3))); +/// assert_eq!(r.next().await, Some(Poll::Ready(1))); +/// assert_eq!(r.next().await, Some(Poll::Ready(2))); +/// assert_eq!(r.next().await, None); +/// +/// let mut p = stream::poll_immediate(Box::pin(stream::once(async { +/// futures::pending!(); +/// 42_u8 +/// }))); +/// assert_eq!(p.next().await, Some(Poll::Pending)); +/// assert_eq!(p.next().await, Some(Poll::Ready(42))); +/// assert_eq!(p.next().await, None); +/// # }); +/// ``` +pub fn poll_immediate<S: Stream>(s: S) -> PollImmediate<S> { + super::assert_stream::<Poll<S::Item>, PollImmediate<S>>(PollImmediate { stream: Some(s) }) +} diff --git a/third_party/rust/futures-util/src/stream/repeat.rs b/third_party/rust/futures-util/src/stream/repeat.rs new file mode 100644 index 0000000000..3f9aa87d5c --- /dev/null +++ b/third_party/rust/futures-util/src/stream/repeat.rs @@ -0,0 +1,58 @@ +use super::assert_stream; +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; + +/// Stream for the [`repeat`] function. +#[derive(Debug, Clone)] +#[must_use = "streams do nothing unless polled"] +pub struct Repeat<T> { + item: T, +} + +/// Create a stream which produces the same item repeatedly. +/// +/// The stream never terminates. Note that you likely want to avoid +/// usage of `collect` or such on the returned stream as it will exhaust +/// available memory as it tries to just fill up all RAM. +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::stream::{self, StreamExt}; +/// +/// let stream = stream::repeat(9); +/// assert_eq!(vec![9, 9, 9], stream.take(3).collect::<Vec<i32>>().await); +/// # }); +/// ``` +pub fn repeat<T>(item: T) -> Repeat<T> +where + T: Clone, +{ + assert_stream::<T, _>(Repeat { item }) +} + +impl<T> Unpin for Repeat<T> {} + +impl<T> Stream for Repeat<T> +where + T: Clone, +{ + type Item = T; + + fn poll_next(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<Self::Item>> { + Poll::Ready(Some(self.item.clone())) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + (usize::max_value(), None) + } +} + +impl<T> FusedStream for Repeat<T> +where + T: Clone, +{ + fn is_terminated(&self) -> bool { + false + } +} diff --git a/third_party/rust/futures-util/src/stream/repeat_with.rs b/third_party/rust/futures-util/src/stream/repeat_with.rs new file mode 100644 index 0000000000..f5a81b4ed4 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/repeat_with.rs @@ -0,0 +1,93 @@ +use super::assert_stream; +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; + +/// An stream that repeats elements of type `A` endlessly by +/// applying the provided closure `F: FnMut() -> A`. +/// +/// This `struct` is created by the [`repeat_with()`] function. +/// See its documentation for more. +#[derive(Debug, Clone)] +#[must_use = "streams do nothing unless polled"] +pub struct RepeatWith<F> { + repeater: F, +} + +impl<A, F: FnMut() -> A> Unpin for RepeatWith<F> {} + +impl<A, F: FnMut() -> A> Stream for RepeatWith<F> { + type Item = A; + + fn poll_next(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<Self::Item>> { + Poll::Ready(Some((&mut self.repeater)())) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + (usize::max_value(), None) + } +} + +impl<A, F: FnMut() -> A> FusedStream for RepeatWith<F> { + fn is_terminated(&self) -> bool { + false + } +} + +/// Creates a new stream that repeats elements of type `A` endlessly by +/// applying the provided closure, the repeater, `F: FnMut() -> A`. +/// +/// The `repeat_with()` function calls the repeater over and over again. +/// +/// Infinite stream like `repeat_with()` are often used with adapters like +/// [`stream.take()`], in order to make them finite. +/// +/// If the element type of the stream you need implements [`Clone`], and +/// it is OK to keep the source element in memory, you should instead use +/// the [`stream.repeat()`] function. +/// +/// # Examples +/// +/// Basic usage: +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::stream::{self, StreamExt}; +/// +/// // let's assume we have some value of a type that is not `Clone` +/// // or which don't want to have in memory just yet because it is expensive: +/// #[derive(PartialEq, Debug)] +/// struct Expensive; +/// +/// // a particular value forever: +/// let mut things = stream::repeat_with(|| Expensive); +/// +/// assert_eq!(Some(Expensive), things.next().await); +/// assert_eq!(Some(Expensive), things.next().await); +/// assert_eq!(Some(Expensive), things.next().await); +/// # }); +/// ``` +/// +/// Using mutation and going finite: +/// +/// ```rust +/// # futures::executor::block_on(async { +/// use futures::stream::{self, StreamExt}; +/// +/// // From the zeroth to the third power of two: +/// let mut curr = 1; +/// let mut pow2 = stream::repeat_with(|| { let tmp = curr; curr *= 2; tmp }) +/// .take(4); +/// +/// assert_eq!(Some(1), pow2.next().await); +/// assert_eq!(Some(2), pow2.next().await); +/// assert_eq!(Some(4), pow2.next().await); +/// assert_eq!(Some(8), pow2.next().await); +/// +/// // ... and now we're done +/// assert_eq!(None, pow2.next().await); +/// # }); +/// ``` +pub fn repeat_with<A, F: FnMut() -> A>(repeater: F) -> RepeatWith<F> { + assert_stream::<A, _>(RepeatWith { repeater }) +} diff --git a/third_party/rust/futures-util/src/stream/select.rs b/third_party/rust/futures-util/src/stream/select.rs new file mode 100644 index 0000000000..0c1e3af782 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/select.rs @@ -0,0 +1,117 @@ +use super::assert_stream; +use crate::stream::{select_with_strategy, PollNext, SelectWithStrategy}; +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`select()`] function. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Select<St1, St2> { + #[pin] + inner: SelectWithStrategy<St1, St2, fn(&mut PollNext)-> PollNext, PollNext>, + } +} + +/// This function will attempt to pull items from both streams. Each +/// stream will be polled in a round-robin fashion, and whenever a stream is +/// ready to yield an item that item is yielded. +/// +/// After one of the two input streams completes, the remaining one will be +/// polled exclusively. The returned stream completes when both input +/// streams have completed. +/// +/// Note that this function consumes both streams and returns a wrapped +/// version of them. +/// +/// ## Examples +/// +/// ```rust +/// # futures::executor::block_on(async { +/// use futures::stream::{ repeat, select, StreamExt }; +/// +/// let left = repeat(1); +/// let right = repeat(2); +/// +/// let mut out = select(left, right); +/// +/// for _ in 0..100 { +/// // We should be alternating. +/// assert_eq!(1, out.select_next_some().await); +/// assert_eq!(2, out.select_next_some().await); +/// } +/// # }); +/// ``` +pub fn select<St1, St2>(stream1: St1, stream2: St2) -> Select<St1, St2> +where + St1: Stream, + St2: Stream<Item = St1::Item>, +{ + fn round_robin(last: &mut PollNext) -> PollNext { + last.toggle() + } + + assert_stream::<St1::Item, _>(Select { + inner: select_with_strategy(stream1, stream2, round_robin), + }) +} + +impl<St1, St2> Select<St1, St2> { + /// Acquires a reference to the underlying streams that this combinator is + /// pulling from. + pub fn get_ref(&self) -> (&St1, &St2) { + self.inner.get_ref() + } + + /// Acquires a mutable reference to the underlying streams that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// stream which may otherwise confuse this combinator. + pub fn get_mut(&mut self) -> (&mut St1, &mut St2) { + self.inner.get_mut() + } + + /// Acquires a pinned mutable reference to the underlying streams that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// stream which may otherwise confuse this combinator. + pub fn get_pin_mut(self: Pin<&mut Self>) -> (Pin<&mut St1>, Pin<&mut St2>) { + let this = self.project(); + this.inner.get_pin_mut() + } + + /// Consumes this combinator, returning the underlying streams. + /// + /// Note that this may discard intermediate state of this combinator, so + /// care should be taken to avoid losing resources when this is called. + pub fn into_inner(self) -> (St1, St2) { + self.inner.into_inner() + } +} + +impl<St1, St2> FusedStream for Select<St1, St2> +where + St1: Stream, + St2: Stream<Item = St1::Item>, +{ + fn is_terminated(&self) -> bool { + self.inner.is_terminated() + } +} + +impl<St1, St2> Stream for Select<St1, St2> +where + St1: Stream, + St2: Stream<Item = St1::Item>, +{ + type Item = St1::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<St1::Item>> { + let this = self.project(); + this.inner.poll_next(cx) + } +} diff --git a/third_party/rust/futures-util/src/stream/select_all.rs b/third_party/rust/futures-util/src/stream/select_all.rs new file mode 100644 index 0000000000..3474331adc --- /dev/null +++ b/third_party/rust/futures-util/src/stream/select_all.rs @@ -0,0 +1,254 @@ +//! An unbounded set of streams + +use core::fmt::{self, Debug}; +use core::iter::FromIterator; +use core::pin::Pin; + +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; + +use pin_project_lite::pin_project; + +use super::assert_stream; +use crate::stream::{futures_unordered, FuturesUnordered, StreamExt, StreamFuture}; + +pin_project! { + /// An unbounded set of streams + /// + /// This "combinator" provides the ability to maintain a set of streams + /// and drive them all to completion. + /// + /// Streams are pushed into this set and their realized values are + /// yielded as they become ready. Streams will only be polled when they + /// generate notifications. This allows to coordinate a large number of streams. + /// + /// Note that you can create a ready-made `SelectAll` via the + /// `select_all` function in the `stream` module, or you can start with an + /// empty set with the `SelectAll::new` constructor. + #[must_use = "streams do nothing unless polled"] + pub struct SelectAll<St> { + #[pin] + inner: FuturesUnordered<StreamFuture<St>>, + } +} + +impl<St: Debug> Debug for SelectAll<St> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "SelectAll {{ ... }}") + } +} + +impl<St: Stream + Unpin> SelectAll<St> { + /// Constructs a new, empty `SelectAll` + /// + /// The returned `SelectAll` does not contain any streams and, in this + /// state, `SelectAll::poll` will return `Poll::Ready(None)`. + pub fn new() -> Self { + Self { inner: FuturesUnordered::new() } + } + + /// Returns the number of streams contained in the set. + /// + /// This represents the total number of in-flight streams. + pub fn len(&self) -> usize { + self.inner.len() + } + + /// Returns `true` if the set contains no streams + pub fn is_empty(&self) -> bool { + self.inner.is_empty() + } + + /// Push a stream into the set. + /// + /// This function submits the given stream to the set for managing. This + /// function will not call `poll` on the submitted stream. The caller must + /// ensure that `SelectAll::poll` is called in order to receive task + /// notifications. + pub fn push(&mut self, stream: St) { + self.inner.push(stream.into_future()); + } + + /// Returns an iterator that allows inspecting each stream in the set. + pub fn iter(&self) -> Iter<'_, St> { + Iter(self.inner.iter()) + } + + /// Returns an iterator that allows modifying each stream in the set. + pub fn iter_mut(&mut self) -> IterMut<'_, St> { + IterMut(self.inner.iter_mut()) + } + + /// Clears the set, removing all streams. + pub fn clear(&mut self) { + self.inner.clear() + } +} + +impl<St: Stream + Unpin> Default for SelectAll<St> { + fn default() -> Self { + Self::new() + } +} + +impl<St: Stream + Unpin> Stream for SelectAll<St> { + type Item = St::Item; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + loop { + match ready!(self.inner.poll_next_unpin(cx)) { + Some((Some(item), remaining)) => { + self.push(remaining); + return Poll::Ready(Some(item)); + } + Some((None, _)) => { + // `FuturesUnordered` thinks it isn't terminated + // because it yielded a Some. + // We do not return, but poll `FuturesUnordered` + // in the next loop iteration. + } + None => return Poll::Ready(None), + } + } + } +} + +impl<St: Stream + Unpin> FusedStream for SelectAll<St> { + fn is_terminated(&self) -> bool { + self.inner.is_terminated() + } +} + +/// Convert a list of streams into a `Stream` of results from the streams. +/// +/// This essentially takes a list of streams (e.g. a vector, an iterator, etc.) +/// and bundles them together into a single stream. +/// The stream will yield items as they become available on the underlying +/// streams internally, in the order they become available. +/// +/// Note that the returned set can also be used to dynamically push more +/// streams into the set as they become available. +/// +/// This function is only available when the `std` or `alloc` feature of this +/// library is activated, and it is activated by default. +pub fn select_all<I>(streams: I) -> SelectAll<I::Item> +where + I: IntoIterator, + I::Item: Stream + Unpin, +{ + let mut set = SelectAll::new(); + + for stream in streams { + set.push(stream); + } + + assert_stream::<<I::Item as Stream>::Item, _>(set) +} + +impl<St: Stream + Unpin> FromIterator<St> for SelectAll<St> { + fn from_iter<T: IntoIterator<Item = St>>(iter: T) -> Self { + select_all(iter) + } +} + +impl<St: Stream + Unpin> Extend<St> for SelectAll<St> { + fn extend<T: IntoIterator<Item = St>>(&mut self, iter: T) { + for st in iter { + self.push(st) + } + } +} + +impl<St: Stream + Unpin> IntoIterator for SelectAll<St> { + type Item = St; + type IntoIter = IntoIter<St>; + + fn into_iter(self) -> Self::IntoIter { + IntoIter(self.inner.into_iter()) + } +} + +impl<'a, St: Stream + Unpin> IntoIterator for &'a SelectAll<St> { + type Item = &'a St; + type IntoIter = Iter<'a, St>; + + fn into_iter(self) -> Self::IntoIter { + self.iter() + } +} + +impl<'a, St: Stream + Unpin> IntoIterator for &'a mut SelectAll<St> { + type Item = &'a mut St; + type IntoIter = IterMut<'a, St>; + + fn into_iter(self) -> Self::IntoIter { + self.iter_mut() + } +} + +/// Immutable iterator over all streams in the unordered set. +#[derive(Debug)] +pub struct Iter<'a, St: Unpin>(futures_unordered::Iter<'a, StreamFuture<St>>); + +/// Mutable iterator over all streams in the unordered set. +#[derive(Debug)] +pub struct IterMut<'a, St: Unpin>(futures_unordered::IterMut<'a, StreamFuture<St>>); + +/// Owned iterator over all streams in the unordered set. +#[derive(Debug)] +pub struct IntoIter<St: Unpin>(futures_unordered::IntoIter<StreamFuture<St>>); + +impl<'a, St: Stream + Unpin> Iterator for Iter<'a, St> { + type Item = &'a St; + + fn next(&mut self) -> Option<Self::Item> { + let st = self.0.next()?; + let next = st.get_ref(); + // This should always be true because FuturesUnordered removes completed futures. + debug_assert!(next.is_some()); + next + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.0.size_hint() + } +} + +impl<St: Stream + Unpin> ExactSizeIterator for Iter<'_, St> {} + +impl<'a, St: Stream + Unpin> Iterator for IterMut<'a, St> { + type Item = &'a mut St; + + fn next(&mut self) -> Option<Self::Item> { + let st = self.0.next()?; + let next = st.get_mut(); + // This should always be true because FuturesUnordered removes completed futures. + debug_assert!(next.is_some()); + next + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.0.size_hint() + } +} + +impl<St: Stream + Unpin> ExactSizeIterator for IterMut<'_, St> {} + +impl<St: Stream + Unpin> Iterator for IntoIter<St> { + type Item = St; + + fn next(&mut self) -> Option<Self::Item> { + let st = self.0.next()?; + let next = st.into_inner(); + // This should always be true because FuturesUnordered removes completed futures. + debug_assert!(next.is_some()); + next + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.0.size_hint() + } +} + +impl<St: Stream + Unpin> ExactSizeIterator for IntoIter<St> {} diff --git a/third_party/rust/futures-util/src/stream/select_with_strategy.rs b/third_party/rust/futures-util/src/stream/select_with_strategy.rs new file mode 100644 index 0000000000..224d5f821c --- /dev/null +++ b/third_party/rust/futures-util/src/stream/select_with_strategy.rs @@ -0,0 +1,304 @@ +use super::assert_stream; +use core::{fmt, pin::Pin}; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +/// Type to tell [`SelectWithStrategy`] which stream to poll next. +#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash)] +pub enum PollNext { + /// Poll the first stream. + Left, + /// Poll the second stream. + Right, +} + +impl PollNext { + /// Toggle the value and return the old one. + pub fn toggle(&mut self) -> Self { + let old = *self; + *self = self.other(); + old + } + + fn other(&self) -> PollNext { + match self { + PollNext::Left => PollNext::Right, + PollNext::Right => PollNext::Left, + } + } +} + +impl Default for PollNext { + fn default() -> Self { + PollNext::Left + } +} + +enum InternalState { + Start, + LeftFinished, + RightFinished, + BothFinished, +} + +impl InternalState { + fn finish(&mut self, ps: PollNext) { + match (&self, ps) { + (InternalState::Start, PollNext::Left) => { + *self = InternalState::LeftFinished; + } + (InternalState::Start, PollNext::Right) => { + *self = InternalState::RightFinished; + } + (InternalState::LeftFinished, PollNext::Right) + | (InternalState::RightFinished, PollNext::Left) => { + *self = InternalState::BothFinished; + } + _ => {} + } + } +} + +pin_project! { + /// Stream for the [`select_with_strategy()`] function. See function docs for details. + #[must_use = "streams do nothing unless polled"] + #[project = SelectWithStrategyProj] + pub struct SelectWithStrategy<St1, St2, Clos, State> { + #[pin] + stream1: St1, + #[pin] + stream2: St2, + internal_state: InternalState, + state: State, + clos: Clos, + } +} + +/// This function will attempt to pull items from both streams. You provide a +/// closure to tell [`SelectWithStrategy`] which stream to poll. The closure can +/// store state on `SelectWithStrategy` to which it will receive a `&mut` on every +/// invocation. This allows basing the strategy on prior choices. +/// +/// After one of the two input streams completes, the remaining one will be +/// polled exclusively. The returned stream completes when both input +/// streams have completed. +/// +/// Note that this function consumes both streams and returns a wrapped +/// version of them. +/// +/// ## Examples +/// +/// ### Priority +/// This example shows how to always prioritize the left stream. +/// +/// ```rust +/// # futures::executor::block_on(async { +/// use futures::stream::{ repeat, select_with_strategy, PollNext, StreamExt }; +/// +/// let left = repeat(1); +/// let right = repeat(2); +/// +/// // We don't need any state, so let's make it an empty tuple. +/// // We must provide some type here, as there is no way for the compiler +/// // to infer it. As we don't need to capture variables, we can just +/// // use a function pointer instead of a closure. +/// fn prio_left(_: &mut ()) -> PollNext { PollNext::Left } +/// +/// let mut out = select_with_strategy(left, right, prio_left); +/// +/// for _ in 0..100 { +/// // Whenever we poll out, we will alwas get `1`. +/// assert_eq!(1, out.select_next_some().await); +/// } +/// # }); +/// ``` +/// +/// ### Round Robin +/// This example shows how to select from both streams round robin. +/// Note: this special case is provided by [`futures-util::stream::select`]. +/// +/// ```rust +/// # futures::executor::block_on(async { +/// use futures::stream::{ repeat, select_with_strategy, PollNext, StreamExt }; +/// +/// let left = repeat(1); +/// let right = repeat(2); +/// +/// let rrobin = |last: &mut PollNext| last.toggle(); +/// +/// let mut out = select_with_strategy(left, right, rrobin); +/// +/// for _ in 0..100 { +/// // We should be alternating now. +/// assert_eq!(1, out.select_next_some().await); +/// assert_eq!(2, out.select_next_some().await); +/// } +/// # }); +/// ``` +pub fn select_with_strategy<St1, St2, Clos, State>( + stream1: St1, + stream2: St2, + which: Clos, +) -> SelectWithStrategy<St1, St2, Clos, State> +where + St1: Stream, + St2: Stream<Item = St1::Item>, + Clos: FnMut(&mut State) -> PollNext, + State: Default, +{ + assert_stream::<St1::Item, _>(SelectWithStrategy { + stream1, + stream2, + state: Default::default(), + internal_state: InternalState::Start, + clos: which, + }) +} + +impl<St1, St2, Clos, State> SelectWithStrategy<St1, St2, Clos, State> { + /// Acquires a reference to the underlying streams that this combinator is + /// pulling from. + pub fn get_ref(&self) -> (&St1, &St2) { + (&self.stream1, &self.stream2) + } + + /// Acquires a mutable reference to the underlying streams that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// stream which may otherwise confuse this combinator. + pub fn get_mut(&mut self) -> (&mut St1, &mut St2) { + (&mut self.stream1, &mut self.stream2) + } + + /// Acquires a pinned mutable reference to the underlying streams that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// stream which may otherwise confuse this combinator. + pub fn get_pin_mut(self: Pin<&mut Self>) -> (Pin<&mut St1>, Pin<&mut St2>) { + let this = self.project(); + (this.stream1, this.stream2) + } + + /// Consumes this combinator, returning the underlying streams. + /// + /// Note that this may discard intermediate state of this combinator, so + /// care should be taken to avoid losing resources when this is called. + pub fn into_inner(self) -> (St1, St2) { + (self.stream1, self.stream2) + } +} + +impl<St1, St2, Clos, State> FusedStream for SelectWithStrategy<St1, St2, Clos, State> +where + St1: Stream, + St2: Stream<Item = St1::Item>, + Clos: FnMut(&mut State) -> PollNext, +{ + fn is_terminated(&self) -> bool { + match self.internal_state { + InternalState::BothFinished => true, + _ => false, + } + } +} + +#[inline] +fn poll_side<St1, St2, Clos, State>( + select: &mut SelectWithStrategyProj<'_, St1, St2, Clos, State>, + side: PollNext, + cx: &mut Context<'_>, +) -> Poll<Option<St1::Item>> +where + St1: Stream, + St2: Stream<Item = St1::Item>, +{ + match side { + PollNext::Left => select.stream1.as_mut().poll_next(cx), + PollNext::Right => select.stream2.as_mut().poll_next(cx), + } +} + +#[inline] +fn poll_inner<St1, St2, Clos, State>( + select: &mut SelectWithStrategyProj<'_, St1, St2, Clos, State>, + side: PollNext, + cx: &mut Context<'_>, +) -> Poll<Option<St1::Item>> +where + St1: Stream, + St2: Stream<Item = St1::Item>, +{ + let first_done = match poll_side(select, side, cx) { + Poll::Ready(Some(item)) => return Poll::Ready(Some(item)), + Poll::Ready(None) => { + select.internal_state.finish(side); + true + } + Poll::Pending => false, + }; + let other = side.other(); + match poll_side(select, other, cx) { + Poll::Ready(None) => { + select.internal_state.finish(other); + if first_done { + Poll::Ready(None) + } else { + Poll::Pending + } + } + a => a, + } +} + +impl<St1, St2, Clos, State> Stream for SelectWithStrategy<St1, St2, Clos, State> +where + St1: Stream, + St2: Stream<Item = St1::Item>, + Clos: FnMut(&mut State) -> PollNext, +{ + type Item = St1::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<St1::Item>> { + let mut this = self.project(); + + match this.internal_state { + InternalState::Start => { + let next_side = (this.clos)(this.state); + poll_inner(&mut this, next_side, cx) + } + InternalState::LeftFinished => match this.stream2.poll_next(cx) { + Poll::Ready(None) => { + *this.internal_state = InternalState::BothFinished; + Poll::Ready(None) + } + a => a, + }, + InternalState::RightFinished => match this.stream1.poll_next(cx) { + Poll::Ready(None) => { + *this.internal_state = InternalState::BothFinished; + Poll::Ready(None) + } + a => a, + }, + InternalState::BothFinished => Poll::Ready(None), + } + } +} + +impl<St1, St2, Clos, State> fmt::Debug for SelectWithStrategy<St1, St2, Clos, State> +where + St1: fmt::Debug, + St2: fmt::Debug, + State: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("SelectWithStrategy") + .field("stream1", &self.stream1) + .field("stream2", &self.stream2) + .field("state", &self.state) + .finish() + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/all.rs b/third_party/rust/futures-util/src/stream/stream/all.rs new file mode 100644 index 0000000000..ba2baa5cf1 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/all.rs @@ -0,0 +1,92 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`all`](super::StreamExt::all) method. + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct All<St, Fut, F> { + #[pin] + stream: St, + f: F, + accum: Option<bool>, + #[pin] + future: Option<Fut>, + } +} + +impl<St, Fut, F> fmt::Debug for All<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("All") + .field("stream", &self.stream) + .field("accum", &self.accum) + .field("future", &self.future) + .finish() + } +} + +impl<St, Fut, F> All<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, accum: Some(true), future: None } + } +} + +impl<St, Fut, F> FusedFuture for All<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + fn is_terminated(&self) -> bool { + self.accum.is_none() && self.future.is_none() + } +} + +impl<St, Fut, F> Future for All<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + type Output = bool; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<bool> { + let mut this = self.project(); + Poll::Ready(loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + // we're currently processing a future to produce a new accum value + let acc = this.accum.unwrap() && ready!(fut.poll(cx)); + if !acc { + break false; + } // early exit + *this.accum = Some(acc); + this.future.set(None); + } else if this.accum.is_some() { + // we're waiting on a new item from the stream + match ready!(this.stream.as_mut().poll_next(cx)) { + Some(item) => { + this.future.set(Some((this.f)(item))); + } + None => { + break this.accum.take().unwrap(); + } + } + } else { + panic!("All polled after completion") + } + }) + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/any.rs b/third_party/rust/futures-util/src/stream/stream/any.rs new file mode 100644 index 0000000000..f023125c70 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/any.rs @@ -0,0 +1,92 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`any`](super::StreamExt::any) method. + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Any<St, Fut, F> { + #[pin] + stream: St, + f: F, + accum: Option<bool>, + #[pin] + future: Option<Fut>, + } +} + +impl<St, Fut, F> fmt::Debug for Any<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Any") + .field("stream", &self.stream) + .field("accum", &self.accum) + .field("future", &self.future) + .finish() + } +} + +impl<St, Fut, F> Any<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, accum: Some(false), future: None } + } +} + +impl<St, Fut, F> FusedFuture for Any<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + fn is_terminated(&self) -> bool { + self.accum.is_none() && self.future.is_none() + } +} + +impl<St, Fut, F> Future for Any<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + type Output = bool; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<bool> { + let mut this = self.project(); + Poll::Ready(loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + // we're currently processing a future to produce a new accum value + let acc = this.accum.unwrap() || ready!(fut.poll(cx)); + if acc { + break true; + } // early exit + *this.accum = Some(acc); + this.future.set(None); + } else if this.accum.is_some() { + // we're waiting on a new item from the stream + match ready!(this.stream.as_mut().poll_next(cx)) { + Some(item) => { + this.future.set(Some((this.f)(item))); + } + None => { + break this.accum.take().unwrap(); + } + } + } else { + panic!("Any polled after completion") + } + }) + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/buffer_unordered.rs b/third_party/rust/futures-util/src/stream/stream/buffer_unordered.rs new file mode 100644 index 0000000000..91b0f6bcce --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/buffer_unordered.rs @@ -0,0 +1,120 @@ +use crate::stream::{Fuse, FuturesUnordered, StreamExt}; +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`buffer_unordered`](super::StreamExt::buffer_unordered) + /// method. + #[must_use = "streams do nothing unless polled"] + pub struct BufferUnordered<St> + where + St: Stream, + { + #[pin] + stream: Fuse<St>, + in_progress_queue: FuturesUnordered<St::Item>, + max: usize, + } +} + +impl<St> fmt::Debug for BufferUnordered<St> +where + St: Stream + fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("BufferUnordered") + .field("stream", &self.stream) + .field("in_progress_queue", &self.in_progress_queue) + .field("max", &self.max) + .finish() + } +} + +impl<St> BufferUnordered<St> +where + St: Stream, + St::Item: Future, +{ + pub(super) fn new(stream: St, n: usize) -> Self { + Self { + stream: super::Fuse::new(stream), + in_progress_queue: FuturesUnordered::new(), + max: n, + } + } + + delegate_access_inner!(stream, St, (.)); +} + +impl<St> Stream for BufferUnordered<St> +where + St: Stream, + St::Item: Future, +{ + type Item = <St::Item as Future>::Output; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + // First up, try to spawn off as many futures as possible by filling up + // our queue of futures. + while this.in_progress_queue.len() < *this.max { + match this.stream.as_mut().poll_next(cx) { + Poll::Ready(Some(fut)) => this.in_progress_queue.push(fut), + Poll::Ready(None) | Poll::Pending => break, + } + } + + // Attempt to pull the next value from the in_progress_queue + match this.in_progress_queue.poll_next_unpin(cx) { + x @ Poll::Pending | x @ Poll::Ready(Some(_)) => return x, + Poll::Ready(None) => {} + } + + // If more values are still coming from the stream, we're not done yet + if this.stream.is_done() { + Poll::Ready(None) + } else { + Poll::Pending + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let queue_len = self.in_progress_queue.len(); + let (lower, upper) = self.stream.size_hint(); + let lower = lower.saturating_add(queue_len); + let upper = match upper { + Some(x) => x.checked_add(queue_len), + None => None, + }; + (lower, upper) + } +} + +impl<St> FusedStream for BufferUnordered<St> +where + St: Stream, + St::Item: Future, +{ + fn is_terminated(&self) -> bool { + self.in_progress_queue.is_terminated() && self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for BufferUnordered<S> +where + S: Stream + Sink<Item>, + S::Item: Future, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/buffered.rs b/third_party/rust/futures-util/src/stream/stream/buffered.rs new file mode 100644 index 0000000000..5854eb7ea5 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/buffered.rs @@ -0,0 +1,118 @@ +use crate::stream::{Fuse, FusedStream, FuturesOrdered, StreamExt}; +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`buffered`](super::StreamExt::buffered) method. + #[must_use = "streams do nothing unless polled"] + pub struct Buffered<St> + where + St: Stream, + St::Item: Future, + { + #[pin] + stream: Fuse<St>, + in_progress_queue: FuturesOrdered<St::Item>, + max: usize, + } +} + +impl<St> fmt::Debug for Buffered<St> +where + St: Stream + fmt::Debug, + St::Item: Future, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Buffered") + .field("stream", &self.stream) + .field("in_progress_queue", &self.in_progress_queue) + .field("max", &self.max) + .finish() + } +} + +impl<St> Buffered<St> +where + St: Stream, + St::Item: Future, +{ + pub(super) fn new(stream: St, n: usize) -> Self { + Self { stream: super::Fuse::new(stream), in_progress_queue: FuturesOrdered::new(), max: n } + } + + delegate_access_inner!(stream, St, (.)); +} + +impl<St> Stream for Buffered<St> +where + St: Stream, + St::Item: Future, +{ + type Item = <St::Item as Future>::Output; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + // First up, try to spawn off as many futures as possible by filling up + // our queue of futures. + while this.in_progress_queue.len() < *this.max { + match this.stream.as_mut().poll_next(cx) { + Poll::Ready(Some(fut)) => this.in_progress_queue.push_back(fut), + Poll::Ready(None) | Poll::Pending => break, + } + } + + // Attempt to pull the next value from the in_progress_queue + let res = this.in_progress_queue.poll_next_unpin(cx); + if let Some(val) = ready!(res) { + return Poll::Ready(Some(val)); + } + + // If more values are still coming from the stream, we're not done yet + if this.stream.is_done() { + Poll::Ready(None) + } else { + Poll::Pending + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let queue_len = self.in_progress_queue.len(); + let (lower, upper) = self.stream.size_hint(); + let lower = lower.saturating_add(queue_len); + let upper = match upper { + Some(x) => x.checked_add(queue_len), + None => None, + }; + (lower, upper) + } +} + +impl<St> FusedStream for Buffered<St> +where + St: Stream, + St::Item: Future, +{ + fn is_terminated(&self) -> bool { + self.stream.is_done() && self.in_progress_queue.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for Buffered<S> +where + S: Stream + Sink<Item>, + S::Item: Future, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/catch_unwind.rs b/third_party/rust/futures-util/src/stream/stream/catch_unwind.rs new file mode 100644 index 0000000000..09a6dc1b76 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/catch_unwind.rs @@ -0,0 +1,61 @@ +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; +use std::any::Any; +use std::panic::{catch_unwind, AssertUnwindSafe, UnwindSafe}; +use std::pin::Pin; + +pin_project! { + /// Stream for the [`catch_unwind`](super::StreamExt::catch_unwind) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct CatchUnwind<St> { + #[pin] + stream: St, + caught_unwind: bool, + } +} + +impl<St: Stream + UnwindSafe> CatchUnwind<St> { + pub(super) fn new(stream: St) -> Self { + Self { stream, caught_unwind: false } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St: Stream + UnwindSafe> Stream for CatchUnwind<St> { + type Item = Result<St::Item, Box<dyn Any + Send>>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + if *this.caught_unwind { + Poll::Ready(None) + } else { + let res = catch_unwind(AssertUnwindSafe(|| this.stream.as_mut().poll_next(cx))); + + match res { + Ok(poll) => poll.map(|opt| opt.map(Ok)), + Err(e) => { + *this.caught_unwind = true; + Poll::Ready(Some(Err(e))) + } + } + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.caught_unwind { + (0, Some(0)) + } else { + self.stream.size_hint() + } + } +} + +impl<St: FusedStream + UnwindSafe> FusedStream for CatchUnwind<St> { + fn is_terminated(&self) -> bool { + self.caught_unwind || self.stream.is_terminated() + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/chain.rs b/third_party/rust/futures-util/src/stream/stream/chain.rs new file mode 100644 index 0000000000..36ff1e533d --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/chain.rs @@ -0,0 +1,76 @@ +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`chain`](super::StreamExt::chain) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Chain<St1, St2> { + #[pin] + first: Option<St1>, + #[pin] + second: St2, + } +} + +// All interactions with `Pin<&mut Chain<..>>` happen through these methods +impl<St1, St2> Chain<St1, St2> +where + St1: Stream, + St2: Stream<Item = St1::Item>, +{ + pub(super) fn new(stream1: St1, stream2: St2) -> Self { + Self { first: Some(stream1), second: stream2 } + } +} + +impl<St1, St2> FusedStream for Chain<St1, St2> +where + St1: Stream, + St2: FusedStream<Item = St1::Item>, +{ + fn is_terminated(&self) -> bool { + self.first.is_none() && self.second.is_terminated() + } +} + +impl<St1, St2> Stream for Chain<St1, St2> +where + St1: Stream, + St2: Stream<Item = St1::Item>, +{ + type Item = St1::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + if let Some(first) = this.first.as_mut().as_pin_mut() { + if let Some(item) = ready!(first.poll_next(cx)) { + return Poll::Ready(Some(item)); + } + + this.first.set(None); + } + this.second.poll_next(cx) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if let Some(first) = &self.first { + let (first_lower, first_upper) = first.size_hint(); + let (second_lower, second_upper) = self.second.size_hint(); + + let lower = first_lower.saturating_add(second_lower); + + let upper = match (first_upper, second_upper) { + (Some(x), Some(y)) => x.checked_add(y), + _ => None, + }; + + (lower, upper) + } else { + self.second.size_hint() + } + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/chunks.rs b/third_party/rust/futures-util/src/stream/stream/chunks.rs new file mode 100644 index 0000000000..2a71ebc6cc --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/chunks.rs @@ -0,0 +1,103 @@ +use crate::stream::Fuse; +use alloc::vec::Vec; +use core::mem; +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`chunks`](super::StreamExt::chunks) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Chunks<St: Stream> { + #[pin] + stream: Fuse<St>, + items: Vec<St::Item>, + cap: usize, // https://github.com/rust-lang/futures-rs/issues/1475 + } +} + +impl<St: Stream> Chunks<St> { + pub(super) fn new(stream: St, capacity: usize) -> Self { + assert!(capacity > 0); + + Self { + stream: super::Fuse::new(stream), + items: Vec::with_capacity(capacity), + cap: capacity, + } + } + + fn take(self: Pin<&mut Self>) -> Vec<St::Item> { + let cap = self.cap; + mem::replace(self.project().items, Vec::with_capacity(cap)) + } + + delegate_access_inner!(stream, St, (.)); +} + +impl<St: Stream> Stream for Chunks<St> { + type Item = Vec<St::Item>; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.as_mut().project(); + loop { + match ready!(this.stream.as_mut().poll_next(cx)) { + // Push the item into the buffer and check whether it is full. + // If so, replace our buffer with a new and empty one and return + // the full one. + Some(item) => { + this.items.push(item); + if this.items.len() >= *this.cap { + return Poll::Ready(Some(self.take())); + } + } + + // Since the underlying stream ran out of values, return what we + // have buffered, if we have anything. + None => { + let last = if this.items.is_empty() { + None + } else { + let full_buf = mem::take(this.items); + Some(full_buf) + }; + + return Poll::Ready(last); + } + } + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let chunk_len = usize::from(!self.items.is_empty()); + let (lower, upper) = self.stream.size_hint(); + let lower = (lower / self.cap).saturating_add(chunk_len); + let upper = match upper { + Some(x) => x.checked_add(chunk_len), + None => None, + }; + (lower, upper) + } +} + +impl<St: FusedStream> FusedStream for Chunks<St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() && self.items.is_empty() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for Chunks<S> +where + S: Stream + Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/collect.rs b/third_party/rust/futures-util/src/stream/stream/collect.rs new file mode 100644 index 0000000000..970ac26dbf --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/collect.rs @@ -0,0 +1,56 @@ +use core::mem; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`collect`](super::StreamExt::collect) method. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Collect<St, C> { + #[pin] + stream: St, + collection: C, + } +} + +impl<St: Stream, C: Default> Collect<St, C> { + fn finish(self: Pin<&mut Self>) -> C { + mem::take(self.project().collection) + } + + pub(super) fn new(stream: St) -> Self { + Self { stream, collection: Default::default() } + } +} + +impl<St, C> FusedFuture for Collect<St, C> +where + St: FusedStream, + C: Default + Extend<St::Item>, +{ + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St, C> Future for Collect<St, C> +where + St: Stream, + C: Default + Extend<St::Item>, +{ + type Output = C; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<C> { + let mut this = self.as_mut().project(); + loop { + match ready!(this.stream.as_mut().poll_next(cx)) { + Some(e) => this.collection.extend(Some(e)), + None => return Poll::Ready(self.finish()), + } + } + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/concat.rs b/third_party/rust/futures-util/src/stream/stream/concat.rs new file mode 100644 index 0000000000..7e058b2315 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/concat.rs @@ -0,0 +1,62 @@ +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`concat`](super::StreamExt::concat) method. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Concat<St: Stream> { + #[pin] + stream: St, + accum: Option<St::Item>, + } +} + +impl<St> Concat<St> +where + St: Stream, + St::Item: Extend<<St::Item as IntoIterator>::Item> + IntoIterator + Default, +{ + pub(super) fn new(stream: St) -> Self { + Self { stream, accum: None } + } +} + +impl<St> Future for Concat<St> +where + St: Stream, + St::Item: Extend<<St::Item as IntoIterator>::Item> + IntoIterator + Default, +{ + type Output = St::Item; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut this = self.project(); + + loop { + match ready!(this.stream.as_mut().poll_next(cx)) { + None => return Poll::Ready(this.accum.take().unwrap_or_default()), + Some(e) => { + if let Some(a) = this.accum { + a.extend(e) + } else { + *this.accum = Some(e) + } + } + } + } + } +} + +impl<St> FusedFuture for Concat<St> +where + St: FusedStream, + St::Item: Extend<<St::Item as IntoIterator>::Item> + IntoIterator + Default, +{ + fn is_terminated(&self) -> bool { + self.accum.is_none() && self.stream.is_terminated() + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/count.rs b/third_party/rust/futures-util/src/stream/stream/count.rs new file mode 100644 index 0000000000..513cab7b6a --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/count.rs @@ -0,0 +1,53 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`count`](super::StreamExt::count) method. + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Count<St> { + #[pin] + stream: St, + count: usize + } +} + +impl<St> fmt::Debug for Count<St> +where + St: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Count").field("stream", &self.stream).field("count", &self.count).finish() + } +} + +impl<St: Stream> Count<St> { + pub(super) fn new(stream: St) -> Self { + Self { stream, count: 0 } + } +} + +impl<St: FusedStream> FusedFuture for Count<St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St: Stream> Future for Count<St> { + type Output = usize; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut this = self.project(); + + Poll::Ready(loop { + match ready!(this.stream.as_mut().poll_next(cx)) { + Some(_) => *this.count += 1, + None => break *this.count, + } + }) + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/cycle.rs b/third_party/rust/futures-util/src/stream/stream/cycle.rs new file mode 100644 index 0000000000..507431d24f --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/cycle.rs @@ -0,0 +1,68 @@ +use core::pin::Pin; +use core::usize; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`cycle`](super::StreamExt::cycle) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Cycle<St> { + orig: St, + #[pin] + stream: St, + } +} + +impl<St> Cycle<St> +where + St: Clone + Stream, +{ + pub(super) fn new(stream: St) -> Self { + Self { orig: stream.clone(), stream } + } +} + +impl<St> Stream for Cycle<St> +where + St: Clone + Stream, +{ + type Item = St::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + match ready!(this.stream.as_mut().poll_next(cx)) { + None => { + this.stream.set(this.orig.clone()); + this.stream.poll_next(cx) + } + item => Poll::Ready(item), + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + // the cycle stream is either empty or infinite + match self.orig.size_hint() { + size @ (0, Some(0)) => size, + (0, _) => (0, None), + _ => (usize::max_value(), None), + } + } +} + +impl<St> FusedStream for Cycle<St> +where + St: Clone + Stream, +{ + fn is_terminated(&self) -> bool { + // the cycle stream is either empty or infinite + if let (0, Some(0)) = self.size_hint() { + true + } else { + false + } + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/enumerate.rs b/third_party/rust/futures-util/src/stream/stream/enumerate.rs new file mode 100644 index 0000000000..1cf9d49aaa --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/enumerate.rs @@ -0,0 +1,64 @@ +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`enumerate`](super::StreamExt::enumerate) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Enumerate<St> { + #[pin] + stream: St, + count: usize, + } +} + +impl<St: Stream> Enumerate<St> { + pub(super) fn new(stream: St) -> Self { + Self { stream, count: 0 } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St: Stream + FusedStream> FusedStream for Enumerate<St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St: Stream> Stream for Enumerate<St> { + type Item = (usize, St::Item); + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let this = self.project(); + + match ready!(this.stream.poll_next(cx)) { + Some(item) => { + let prev_count = *this.count; + *this.count += 1; + Poll::Ready(Some((prev_count, item))) + } + None => Poll::Ready(None), + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.stream.size_hint() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for Enumerate<S> +where + S: Stream + Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/filter.rs b/third_party/rust/futures-util/src/stream/stream/filter.rs new file mode 100644 index 0000000000..997fe9977e --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/filter.rs @@ -0,0 +1,117 @@ +use crate::fns::FnMut1; +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`filter`](super::StreamExt::filter) method. + #[must_use = "streams do nothing unless polled"] + pub struct Filter<St, Fut, F> + where St: Stream, + { + #[pin] + stream: St, + f: F, + #[pin] + pending_fut: Option<Fut>, + pending_item: Option<St::Item>, + } +} + +impl<St, Fut, F> fmt::Debug for Filter<St, Fut, F> +where + St: Stream + fmt::Debug, + St::Item: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Filter") + .field("stream", &self.stream) + .field("pending_fut", &self.pending_fut) + .field("pending_item", &self.pending_item) + .finish() + } +} + +#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 +impl<St, Fut, F> Filter<St, Fut, F> +where + St: Stream, + F: for<'a> FnMut1<&'a St::Item, Output = Fut>, + Fut: Future<Output = bool>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, pending_fut: None, pending_item: None } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> FusedStream for Filter<St, Fut, F> +where + St: Stream + FusedStream, + F: FnMut(&St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + fn is_terminated(&self) -> bool { + self.pending_fut.is_none() && self.stream.is_terminated() + } +} + +#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 +impl<St, Fut, F> Stream for Filter<St, Fut, F> +where + St: Stream, + F: for<'a> FnMut1<&'a St::Item, Output = Fut>, + Fut: Future<Output = bool>, +{ + type Item = St::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<St::Item>> { + let mut this = self.project(); + Poll::Ready(loop { + if let Some(fut) = this.pending_fut.as_mut().as_pin_mut() { + let res = ready!(fut.poll(cx)); + this.pending_fut.set(None); + if res { + break this.pending_item.take(); + } + *this.pending_item = None; + } else if let Some(item) = ready!(this.stream.as_mut().poll_next(cx)) { + this.pending_fut.set(Some(this.f.call_mut(&item))); + *this.pending_item = Some(item); + } else { + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let pending_len = usize::from(self.pending_item.is_some()); + let (_, upper) = self.stream.size_hint(); + let upper = match upper { + Some(x) => x.checked_add(pending_len), + None => None, + }; + (0, upper) // can't know a lower bound, due to the predicate + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item> Sink<Item> for Filter<S, Fut, F> +where + S: Stream + Sink<Item>, + F: FnMut(&S::Item) -> Fut, + Fut: Future<Output = bool>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/filter_map.rs b/third_party/rust/futures-util/src/stream/stream/filter_map.rs new file mode 100644 index 0000000000..6b7d0070df --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/filter_map.rs @@ -0,0 +1,111 @@ +use crate::fns::FnMut1; +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`filter_map`](super::StreamExt::filter_map) method. + #[must_use = "streams do nothing unless polled"] + pub struct FilterMap<St, Fut, F> { + #[pin] + stream: St, + f: F, + #[pin] + pending: Option<Fut>, + } +} + +impl<St, Fut, F> fmt::Debug for FilterMap<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("FilterMap") + .field("stream", &self.stream) + .field("pending", &self.pending) + .finish() + } +} + +impl<St, Fut, F> FilterMap<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, pending: None } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F, T> FusedStream for FilterMap<St, Fut, F> +where + St: Stream + FusedStream, + F: FnMut1<St::Item, Output = Fut>, + Fut: Future<Output = Option<T>>, +{ + fn is_terminated(&self) -> bool { + self.pending.is_none() && self.stream.is_terminated() + } +} + +impl<St, Fut, F, T> Stream for FilterMap<St, Fut, F> +where + St: Stream, + F: FnMut1<St::Item, Output = Fut>, + Fut: Future<Output = Option<T>>, +{ + type Item = T; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T>> { + let mut this = self.project(); + Poll::Ready(loop { + if let Some(p) = this.pending.as_mut().as_pin_mut() { + // We have an item in progress, poll that until it's done + let item = ready!(p.poll(cx)); + this.pending.set(None); + if item.is_some() { + break item; + } + } else if let Some(item) = ready!(this.stream.as_mut().poll_next(cx)) { + // No item in progress, but the stream is still going + this.pending.set(Some(this.f.call_mut(item))); + } else { + // The stream is done + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let pending_len = usize::from(self.pending.is_some()); + let (_, upper) = self.stream.size_hint(); + let upper = match upper { + Some(x) => x.checked_add(pending_len), + None => None, + }; + (0, upper) // can't know a lower bound, due to the predicate + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item> Sink<Item> for FilterMap<S, Fut, F> +where + S: Stream + Sink<Item>, + F: FnMut1<S::Item, Output = Fut>, + Fut: Future, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/flatten.rs b/third_party/rust/futures-util/src/stream/stream/flatten.rs new file mode 100644 index 0000000000..9f6b7a472d --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/flatten.rs @@ -0,0 +1,73 @@ +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`flatten`](super::StreamExt::flatten) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Flatten<St, U> { + #[pin] + stream: St, + #[pin] + next: Option<U>, + } +} + +impl<St, U> Flatten<St, U> { + pub(super) fn new(stream: St) -> Self { + Self { stream, next: None } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St> FusedStream for Flatten<St, St::Item> +where + St: FusedStream, + St::Item: Stream, +{ + fn is_terminated(&self) -> bool { + self.next.is_none() && self.stream.is_terminated() + } +} + +impl<St> Stream for Flatten<St, St::Item> +where + St: Stream, + St::Item: Stream, +{ + type Item = <St::Item as Stream>::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + Poll::Ready(loop { + if let Some(s) = this.next.as_mut().as_pin_mut() { + if let Some(item) = ready!(s.poll_next(cx)) { + break Some(item); + } else { + this.next.set(None); + } + } else if let Some(s) = ready!(this.stream.as_mut().poll_next(cx)) { + this.next.set(Some(s)); + } else { + break None; + } + }) + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for Flatten<S, S::Item> +where + S: Stream + Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/flatten_unordered.rs b/third_party/rust/futures-util/src/stream/stream/flatten_unordered.rs new file mode 100644 index 0000000000..07f971c55a --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/flatten_unordered.rs @@ -0,0 +1,509 @@ +use alloc::sync::Arc; +use core::{ + cell::UnsafeCell, + convert::identity, + fmt, + num::NonZeroUsize, + pin::Pin, + sync::atomic::{AtomicU8, Ordering}, +}; + +use pin_project_lite::pin_project; + +use futures_core::{ + future::Future, + ready, + stream::{FusedStream, Stream}, + task::{Context, Poll, Waker}, +}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use futures_task::{waker, ArcWake}; + +use crate::stream::FuturesUnordered; + +/// There is nothing to poll and stream isn't being +/// polled or waking at the moment. +const NONE: u8 = 0; + +/// Inner streams need to be polled. +const NEED_TO_POLL_INNER_STREAMS: u8 = 1; + +/// The base stream needs to be polled. +const NEED_TO_POLL_STREAM: u8 = 0b10; + +/// It needs to poll base stream and inner streams. +const NEED_TO_POLL_ALL: u8 = NEED_TO_POLL_INNER_STREAMS | NEED_TO_POLL_STREAM; + +/// The current stream is being polled at the moment. +const POLLING: u8 = 0b100; + +/// Inner streams are being woken at the moment. +const WAKING_INNER_STREAMS: u8 = 0b1000; + +/// The base stream is being woken at the moment. +const WAKING_STREAM: u8 = 0b10000; + +/// The base stream and inner streams are being woken at the moment. +const WAKING_ALL: u8 = WAKING_STREAM | WAKING_INNER_STREAMS; + +/// The stream was waked and will be polled. +const WOKEN: u8 = 0b100000; + +/// Determines what needs to be polled, and is stream being polled at the +/// moment or not. +#[derive(Clone, Debug)] +struct SharedPollState { + state: Arc<AtomicU8>, +} + +impl SharedPollState { + /// Constructs new `SharedPollState` with the given state. + fn new(value: u8) -> SharedPollState { + SharedPollState { state: Arc::new(AtomicU8::new(value)) } + } + + /// Attempts to start polling, returning stored state in case of success. + /// Returns `None` if some waker is waking at the moment. + fn start_polling( + &self, + ) -> Option<(u8, PollStateBomb<'_, impl FnOnce(&SharedPollState) -> u8>)> { + let value = self + .state + .fetch_update(Ordering::SeqCst, Ordering::SeqCst, |value| { + if value & WAKING_ALL == NONE { + Some(POLLING) + } else { + None + } + }) + .ok()?; + let bomb = PollStateBomb::new(self, SharedPollState::reset); + + Some((value, bomb)) + } + + /// Starts the waking process and performs bitwise or with the given value. + fn start_waking( + &self, + to_poll: u8, + waking: u8, + ) -> Option<(u8, PollStateBomb<'_, impl FnOnce(&SharedPollState) -> u8>)> { + let value = self + .state + .fetch_update(Ordering::SeqCst, Ordering::SeqCst, |value| { + // Waking process for this waker already started + if value & waking != NONE { + return None; + } + let mut next_value = value | to_poll; + // Only start the waking process if we're not in the polling phase and the stream isn't woken already + if value & (WOKEN | POLLING) == NONE { + next_value |= waking; + } + + if next_value != value { + Some(next_value) + } else { + None + } + }) + .ok()?; + + if value & (WOKEN | POLLING) == NONE { + let bomb = PollStateBomb::new(self, move |state| state.stop_waking(waking)); + + Some((value, bomb)) + } else { + None + } + } + + /// Sets current state to + /// - `!POLLING` allowing to use wakers + /// - `WOKEN` if the state was changed during `POLLING` phase as waker will be called, + /// or `will_be_woken` flag supplied + /// - `!WAKING_ALL` as + /// * Wakers called during the `POLLING` phase won't propagate their calls + /// * `POLLING` phase can't start if some of the wakers are active + /// So no wrapped waker can touch the inner waker's cell, it's safe to poll again. + fn stop_polling(&self, to_poll: u8, will_be_woken: bool) -> u8 { + self.state + .fetch_update(Ordering::SeqCst, Ordering::SeqCst, |mut value| { + let mut next_value = to_poll; + + value &= NEED_TO_POLL_ALL; + if value != NONE || will_be_woken { + next_value |= WOKEN; + } + next_value |= value; + + Some(next_value & !POLLING & !WAKING_ALL) + }) + .unwrap() + } + + /// Toggles state to non-waking, allowing to start polling. + fn stop_waking(&self, waking: u8) -> u8 { + self.state + .fetch_update(Ordering::SeqCst, Ordering::SeqCst, |value| { + let mut next_value = value & !waking; + // Waker will be called only if the current waking state is the same as the specified waker state + if value & WAKING_ALL == waking { + next_value |= WOKEN; + } + + if next_value != value { + Some(next_value) + } else { + None + } + }) + .unwrap_or_else(identity) + } + + /// Resets current state allowing to poll the stream and wake up wakers. + fn reset(&self) -> u8 { + self.state.swap(NEED_TO_POLL_ALL, Ordering::AcqRel) + } +} + +/// Used to execute some function on the given state when dropped. +struct PollStateBomb<'a, F: FnOnce(&SharedPollState) -> u8> { + state: &'a SharedPollState, + drop: Option<F>, +} + +impl<'a, F: FnOnce(&SharedPollState) -> u8> PollStateBomb<'a, F> { + /// Constructs new bomb with the given state. + fn new(state: &'a SharedPollState, drop: F) -> Self { + Self { state, drop: Some(drop) } + } + + /// Deactivates bomb, forces it to not call provided function when dropped. + fn deactivate(mut self) { + self.drop.take(); + } + + /// Manually fires the bomb, returning supplied state. + fn fire(mut self) -> Option<u8> { + self.drop.take().map(|drop| (drop)(self.state)) + } +} + +impl<F: FnOnce(&SharedPollState) -> u8> Drop for PollStateBomb<'_, F> { + fn drop(&mut self) { + if let Some(drop) = self.drop.take() { + (drop)(self.state); + } + } +} + +/// Will update state with the provided value on `wake_by_ref` call +/// and then, if there is a need, call `inner_waker`. +struct InnerWaker { + inner_waker: UnsafeCell<Option<Waker>>, + poll_state: SharedPollState, + need_to_poll: u8, +} + +unsafe impl Send for InnerWaker {} +unsafe impl Sync for InnerWaker {} + +impl InnerWaker { + /// Replaces given waker's inner_waker for polling stream/futures which will + /// update poll state on `wake_by_ref` call. Use only if you need several + /// contexts. + /// + /// ## Safety + /// + /// This function will modify waker's `inner_waker` via `UnsafeCell`, so + /// it should be used only during `POLLING` phase. + unsafe fn replace_waker(self_arc: &mut Arc<Self>, cx: &Context<'_>) -> Waker { + *self_arc.inner_waker.get() = cx.waker().clone().into(); + waker(self_arc.clone()) + } + + /// Attempts to start the waking process for the waker with the given value. + /// If succeeded, then the stream isn't yet woken and not being polled at the moment. + fn start_waking(&self) -> Option<(u8, PollStateBomb<'_, impl FnOnce(&SharedPollState) -> u8>)> { + self.poll_state.start_waking(self.need_to_poll, self.waking_state()) + } + + /// Returns the corresponding waking state toggled by this waker. + fn waking_state(&self) -> u8 { + self.need_to_poll << 3 + } +} + +impl ArcWake for InnerWaker { + fn wake_by_ref(self_arc: &Arc<Self>) { + if let Some((_, state_bomb)) = self_arc.start_waking() { + // Safety: now state is not `POLLING` + let waker_opt = unsafe { self_arc.inner_waker.get().as_ref().unwrap() }; + + if let Some(inner_waker) = waker_opt.clone() { + // Stop waking to allow polling stream + let poll_state_value = state_bomb.fire().unwrap(); + + // Here we want to call waker only if stream isn't woken yet and + // also to optimize the case when two wakers are called at the same time. + // + // In this case the best strategy will be to propagate only the latest waker's awake, + // and then poll both entities in a single `poll_next` call + if poll_state_value & (WOKEN | WAKING_ALL) == self_arc.waking_state() { + // Wake up inner waker + inner_waker.wake(); + } + } + } + } +} + +pin_project! { + /// Future which contains optional stream. + /// + /// If it's `Some`, it will attempt to call `poll_next` on it, + /// returning `Some((item, next_item_fut))` in case of `Poll::Ready(Some(...))` + /// or `None` in case of `Poll::Ready(None)`. + /// + /// If `poll_next` will return `Poll::Pending`, it will be forwarded to + /// the future and current task will be notified by waker. + #[must_use = "futures do nothing unless you `.await` or poll them"] + struct PollStreamFut<St> { + #[pin] + stream: Option<St>, + } +} + +impl<St> PollStreamFut<St> { + /// Constructs new `PollStreamFut` using given `stream`. + fn new(stream: impl Into<Option<St>>) -> Self { + Self { stream: stream.into() } + } +} + +impl<St: Stream + Unpin> Future for PollStreamFut<St> { + type Output = Option<(St::Item, PollStreamFut<St>)>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut stream = self.project().stream; + + let item = if let Some(stream) = stream.as_mut().as_pin_mut() { + ready!(stream.poll_next(cx)) + } else { + None + }; + let next_item_fut = PollStreamFut::new(stream.get_mut().take()); + let out = item.map(|item| (item, next_item_fut)); + + Poll::Ready(out) + } +} + +pin_project! { + /// Stream for the [`flatten_unordered`](super::StreamExt::flatten_unordered) + /// method. + #[project = FlattenUnorderedProj] + #[must_use = "streams do nothing unless polled"] + pub struct FlattenUnordered<St> where St: Stream { + #[pin] + inner_streams: FuturesUnordered<PollStreamFut<St::Item>>, + #[pin] + stream: St, + poll_state: SharedPollState, + limit: Option<NonZeroUsize>, + is_stream_done: bool, + inner_streams_waker: Arc<InnerWaker>, + stream_waker: Arc<InnerWaker>, + } +} + +impl<St> fmt::Debug for FlattenUnordered<St> +where + St: Stream + fmt::Debug, + St::Item: Stream + fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("FlattenUnordered") + .field("poll_state", &self.poll_state) + .field("inner_streams", &self.inner_streams) + .field("limit", &self.limit) + .field("stream", &self.stream) + .field("is_stream_done", &self.is_stream_done) + .finish() + } +} + +impl<St> FlattenUnordered<St> +where + St: Stream, + St::Item: Stream + Unpin, +{ + pub(super) fn new(stream: St, limit: Option<usize>) -> FlattenUnordered<St> { + let poll_state = SharedPollState::new(NEED_TO_POLL_STREAM); + + FlattenUnordered { + inner_streams: FuturesUnordered::new(), + stream, + is_stream_done: false, + limit: limit.and_then(NonZeroUsize::new), + inner_streams_waker: Arc::new(InnerWaker { + inner_waker: UnsafeCell::new(None), + poll_state: poll_state.clone(), + need_to_poll: NEED_TO_POLL_INNER_STREAMS, + }), + stream_waker: Arc::new(InnerWaker { + inner_waker: UnsafeCell::new(None), + poll_state: poll_state.clone(), + need_to_poll: NEED_TO_POLL_STREAM, + }), + poll_state, + } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St> FlattenUnorderedProj<'_, St> +where + St: Stream, +{ + /// Checks if current `inner_streams` size is less than optional limit. + fn is_exceeded_limit(&self) -> bool { + self.limit.map_or(false, |limit| self.inner_streams.len() >= limit.get()) + } +} + +impl<St> FusedStream for FlattenUnordered<St> +where + St: FusedStream, + St::Item: FusedStream + Unpin, +{ + fn is_terminated(&self) -> bool { + self.stream.is_terminated() && self.inner_streams.is_empty() + } +} + +impl<St> Stream for FlattenUnordered<St> +where + St: Stream, + St::Item: Stream + Unpin, +{ + type Item = <St::Item as Stream>::Item; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut next_item = None; + let mut need_to_poll_next = NONE; + + let mut this = self.as_mut().project(); + + let (mut poll_state_value, state_bomb) = match this.poll_state.start_polling() { + Some(value) => value, + _ => { + // Waker was called, just wait for the next poll + return Poll::Pending; + } + }; + + if poll_state_value & NEED_TO_POLL_STREAM != NONE { + // Safety: now state is `POLLING`. + let stream_waker = unsafe { InnerWaker::replace_waker(this.stream_waker, cx) }; + + // Here we need to poll the base stream. + // + // To improve performance, we will attempt to place as many items as we can + // to the `FuturesUnordered` bucket before polling inner streams + loop { + if this.is_exceeded_limit() || *this.is_stream_done { + // We either exceeded the limit or the stream is exhausted + if !*this.is_stream_done { + // The stream needs to be polled in the next iteration + need_to_poll_next |= NEED_TO_POLL_STREAM; + } + + break; + } else { + match this.stream.as_mut().poll_next(&mut Context::from_waker(&stream_waker)) { + Poll::Ready(Some(inner_stream)) => { + // Add new stream to the inner streams bucket + this.inner_streams.as_mut().push(PollStreamFut::new(inner_stream)); + // Inner streams must be polled afterward + poll_state_value |= NEED_TO_POLL_INNER_STREAMS; + } + Poll::Ready(None) => { + // Mark the stream as done + *this.is_stream_done = true; + } + Poll::Pending => { + break; + } + } + } + } + } + + if poll_state_value & NEED_TO_POLL_INNER_STREAMS != NONE { + // Safety: now state is `POLLING`. + let inner_streams_waker = + unsafe { InnerWaker::replace_waker(this.inner_streams_waker, cx) }; + + match this + .inner_streams + .as_mut() + .poll_next(&mut Context::from_waker(&inner_streams_waker)) + { + Poll::Ready(Some(Some((item, next_item_fut)))) => { + // Push next inner stream item future to the list of inner streams futures + this.inner_streams.as_mut().push(next_item_fut); + // Take the received item + next_item = Some(item); + // On the next iteration, inner streams must be polled again + need_to_poll_next |= NEED_TO_POLL_INNER_STREAMS; + } + Poll::Ready(Some(None)) => { + // On the next iteration, inner streams must be polled again + need_to_poll_next |= NEED_TO_POLL_INNER_STREAMS; + } + _ => {} + } + } + + // We didn't have any `poll_next` panic, so it's time to deactivate the bomb + state_bomb.deactivate(); + + let mut force_wake = + // we need to poll the stream and didn't reach the limit yet + need_to_poll_next & NEED_TO_POLL_STREAM != NONE && !this.is_exceeded_limit() + // or we need to poll inner streams again + || need_to_poll_next & NEED_TO_POLL_INNER_STREAMS != NONE; + + // Stop polling and swap the latest state + poll_state_value = this.poll_state.stop_polling(need_to_poll_next, force_wake); + // If state was changed during `POLLING` phase, need to manually call a waker + force_wake |= poll_state_value & NEED_TO_POLL_ALL != NONE; + + let is_done = *this.is_stream_done && this.inner_streams.is_empty(); + + if next_item.is_some() || is_done { + Poll::Ready(next_item) + } else { + if force_wake { + cx.waker().wake_by_ref(); + } + + Poll::Pending + } + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<St, Item> Sink<Item> for FlattenUnordered<St> +where + St: Stream + Sink<Item>, +{ + type Error = St::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/fold.rs b/third_party/rust/futures-util/src/stream/stream/fold.rs new file mode 100644 index 0000000000..b8b55ecb67 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/fold.rs @@ -0,0 +1,88 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`fold`](super::StreamExt::fold) method. + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Fold<St, Fut, T, F> { + #[pin] + stream: St, + f: F, + accum: Option<T>, + #[pin] + future: Option<Fut>, + } +} + +impl<St, Fut, T, F> fmt::Debug for Fold<St, Fut, T, F> +where + St: fmt::Debug, + Fut: fmt::Debug, + T: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Fold") + .field("stream", &self.stream) + .field("accum", &self.accum) + .field("future", &self.future) + .finish() + } +} + +impl<St, Fut, T, F> Fold<St, Fut, T, F> +where + St: Stream, + F: FnMut(T, St::Item) -> Fut, + Fut: Future<Output = T>, +{ + pub(super) fn new(stream: St, f: F, t: T) -> Self { + Self { stream, f, accum: Some(t), future: None } + } +} + +impl<St, Fut, T, F> FusedFuture for Fold<St, Fut, T, F> +where + St: Stream, + F: FnMut(T, St::Item) -> Fut, + Fut: Future<Output = T>, +{ + fn is_terminated(&self) -> bool { + self.accum.is_none() && self.future.is_none() + } +} + +impl<St, Fut, T, F> Future for Fold<St, Fut, T, F> +where + St: Stream, + F: FnMut(T, St::Item) -> Fut, + Fut: Future<Output = T>, +{ + type Output = T; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<T> { + let mut this = self.project(); + Poll::Ready(loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + // we're currently processing a future to produce a new accum value + *this.accum = Some(ready!(fut.poll(cx))); + this.future.set(None); + } else if this.accum.is_some() { + // we're waiting on a new item from the stream + let res = ready!(this.stream.as_mut().poll_next(cx)); + let a = this.accum.take().unwrap(); + if let Some(item) = res { + this.future.set(Some((this.f)(a, item))); + } else { + break a; + } + } else { + panic!("Fold polled after completion") + } + }) + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/for_each.rs b/third_party/rust/futures-util/src/stream/stream/for_each.rs new file mode 100644 index 0000000000..5302b0e034 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/for_each.rs @@ -0,0 +1,78 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`for_each`](super::StreamExt::for_each) method. + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct ForEach<St, Fut, F> { + #[pin] + stream: St, + f: F, + #[pin] + future: Option<Fut>, + } +} + +impl<St, Fut, F> fmt::Debug for ForEach<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("ForEach") + .field("stream", &self.stream) + .field("future", &self.future) + .finish() + } +} + +impl<St, Fut, F> ForEach<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = ()>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, future: None } + } +} + +impl<St, Fut, F> FusedFuture for ForEach<St, Fut, F> +where + St: FusedStream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = ()>, +{ + fn is_terminated(&self) -> bool { + self.future.is_none() && self.stream.is_terminated() + } +} + +impl<St, Fut, F> Future for ForEach<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = ()>, +{ + type Output = (); + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> { + let mut this = self.project(); + loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + ready!(fut.poll(cx)); + this.future.set(None); + } else if let Some(item) = ready!(this.stream.as_mut().poll_next(cx)) { + this.future.set(Some((this.f)(item))); + } else { + break; + } + } + Poll::Ready(()) + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/for_each_concurrent.rs b/third_party/rust/futures-util/src/stream/stream/for_each_concurrent.rs new file mode 100644 index 0000000000..6c18753eb9 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/for_each_concurrent.rs @@ -0,0 +1,119 @@ +use crate::stream::{FuturesUnordered, StreamExt}; +use core::fmt; +use core::num::NonZeroUsize; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`for_each_concurrent`](super::StreamExt::for_each_concurrent) + /// method. + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct ForEachConcurrent<St, Fut, F> { + #[pin] + stream: Option<St>, + f: F, + futures: FuturesUnordered<Fut>, + limit: Option<NonZeroUsize>, + } +} + +impl<St, Fut, F> fmt::Debug for ForEachConcurrent<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("ForEachConcurrent") + .field("stream", &self.stream) + .field("futures", &self.futures) + .field("limit", &self.limit) + .finish() + } +} + +impl<St, Fut, F> ForEachConcurrent<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = ()>, +{ + pub(super) fn new(stream: St, limit: Option<usize>, f: F) -> Self { + Self { + stream: Some(stream), + // Note: `limit` = 0 gets ignored. + limit: limit.and_then(NonZeroUsize::new), + f, + futures: FuturesUnordered::new(), + } + } +} + +impl<St, Fut, F> FusedFuture for ForEachConcurrent<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = ()>, +{ + fn is_terminated(&self) -> bool { + self.stream.is_none() && self.futures.is_empty() + } +} + +impl<St, Fut, F> Future for ForEachConcurrent<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future<Output = ()>, +{ + type Output = (); + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> { + let mut this = self.project(); + loop { + let mut made_progress_this_iter = false; + + // Check if we've already created a number of futures greater than `limit` + if this.limit.map(|limit| limit.get() > this.futures.len()).unwrap_or(true) { + let mut stream_completed = false; + let elem = if let Some(stream) = this.stream.as_mut().as_pin_mut() { + match stream.poll_next(cx) { + Poll::Ready(Some(elem)) => { + made_progress_this_iter = true; + Some(elem) + } + Poll::Ready(None) => { + stream_completed = true; + None + } + Poll::Pending => None, + } + } else { + None + }; + if stream_completed { + this.stream.set(None); + } + if let Some(elem) = elem { + this.futures.push((this.f)(elem)); + } + } + + match this.futures.poll_next_unpin(cx) { + Poll::Ready(Some(())) => made_progress_this_iter = true, + Poll::Ready(None) => { + if this.stream.is_none() { + return Poll::Ready(()); + } + } + Poll::Pending => {} + } + + if !made_progress_this_iter { + return Poll::Pending; + } + } + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/forward.rs b/third_party/rust/futures-util/src/stream/stream/forward.rs new file mode 100644 index 0000000000..1fe24273aa --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/forward.rs @@ -0,0 +1,75 @@ +use crate::stream::Fuse; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`forward`](super::StreamExt::forward) method. + #[project = ForwardProj] + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Forward<St, Si, Item> { + #[pin] + sink: Option<Si>, + #[pin] + stream: Fuse<St>, + buffered_item: Option<Item>, + } +} + +impl<St, Si, Item> Forward<St, Si, Item> { + pub(crate) fn new(stream: St, sink: Si) -> Self { + Self { sink: Some(sink), stream: Fuse::new(stream), buffered_item: None } + } +} + +impl<St, Si, Item, E> FusedFuture for Forward<St, Si, Item> +where + Si: Sink<Item, Error = E>, + St: Stream<Item = Result<Item, E>>, +{ + fn is_terminated(&self) -> bool { + self.sink.is_none() + } +} + +impl<St, Si, Item, E> Future for Forward<St, Si, Item> +where + Si: Sink<Item, Error = E>, + St: Stream<Item = Result<Item, E>>, +{ + type Output = Result<(), E>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let ForwardProj { mut sink, mut stream, buffered_item } = self.project(); + let mut si = sink.as_mut().as_pin_mut().expect("polled `Forward` after completion"); + + loop { + // If we've got an item buffered already, we need to write it to the + // sink before we can do anything else + if buffered_item.is_some() { + ready!(si.as_mut().poll_ready(cx))?; + si.as_mut().start_send(buffered_item.take().unwrap())?; + } + + match stream.as_mut().poll_next(cx)? { + Poll::Ready(Some(item)) => { + *buffered_item = Some(item); + } + Poll::Ready(None) => { + ready!(si.poll_close(cx))?; + sink.set(None); + return Poll::Ready(Ok(())); + } + Poll::Pending => { + ready!(si.poll_flush(cx))?; + return Poll::Pending; + } + } + } + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/fuse.rs b/third_party/rust/futures-util/src/stream/stream/fuse.rs new file mode 100644 index 0000000000..fe67813e81 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/fuse.rs @@ -0,0 +1,75 @@ +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`fuse`](super::StreamExt::fuse) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Fuse<St> { + #[pin] + stream: St, + done: bool, + } +} + +impl<St> Fuse<St> { + pub(super) fn new(stream: St) -> Self { + Self { stream, done: false } + } + + /// Returns whether the underlying stream has finished or not. + /// + /// If this method returns `true`, then all future calls to poll are + /// guaranteed to return `None`. If this returns `false`, then the + /// underlying stream is still in use. + pub fn is_done(&self) -> bool { + self.done + } + + delegate_access_inner!(stream, St, ()); +} + +impl<S: Stream> FusedStream for Fuse<S> { + fn is_terminated(&self) -> bool { + self.done + } +} + +impl<S: Stream> Stream for Fuse<S> { + type Item = S::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<S::Item>> { + let this = self.project(); + + if *this.done { + return Poll::Ready(None); + } + + let item = ready!(this.stream.poll_next(cx)); + if item.is_none() { + *this.done = true; + } + Poll::Ready(item) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.done { + (0, Some(0)) + } else { + self.stream.size_hint() + } + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S: Stream + Sink<Item>, Item> Sink<Item> for Fuse<S> { + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/into_future.rs b/third_party/rust/futures-util/src/stream/stream/into_future.rs new file mode 100644 index 0000000000..8abfddcccd --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/into_future.rs @@ -0,0 +1,90 @@ +use crate::stream::StreamExt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; + +/// Future for the [`into_future`](super::StreamExt::into_future) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct StreamFuture<St> { + stream: Option<St>, +} + +impl<St: Stream + Unpin> StreamFuture<St> { + pub(super) fn new(stream: St) -> Self { + Self { stream: Some(stream) } + } + + /// Acquires a reference to the underlying stream that this combinator is + /// pulling from. + /// + /// This method returns an `Option` to account for the fact that `StreamFuture`'s + /// implementation of `Future::poll` consumes the underlying stream during polling + /// in order to return it to the caller of `Future::poll` if the stream yielded + /// an element. + pub fn get_ref(&self) -> Option<&St> { + self.stream.as_ref() + } + + /// Acquires a mutable reference to the underlying stream that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// stream which may otherwise confuse this combinator. + /// + /// This method returns an `Option` to account for the fact that `StreamFuture`'s + /// implementation of `Future::poll` consumes the underlying stream during polling + /// in order to return it to the caller of `Future::poll` if the stream yielded + /// an element. + pub fn get_mut(&mut self) -> Option<&mut St> { + self.stream.as_mut() + } + + /// Acquires a pinned mutable reference to the underlying stream that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// stream which may otherwise confuse this combinator. + /// + /// This method returns an `Option` to account for the fact that `StreamFuture`'s + /// implementation of `Future::poll` consumes the underlying stream during polling + /// in order to return it to the caller of `Future::poll` if the stream yielded + /// an element. + pub fn get_pin_mut(self: Pin<&mut Self>) -> Option<Pin<&mut St>> { + self.get_mut().stream.as_mut().map(Pin::new) + } + + /// Consumes this combinator, returning the underlying stream. + /// + /// Note that this may discard intermediate state of this combinator, so + /// care should be taken to avoid losing resources when this is called. + /// + /// This method returns an `Option` to account for the fact that `StreamFuture`'s + /// implementation of `Future::poll` consumes the underlying stream during polling + /// in order to return it to the caller of `Future::poll` if the stream yielded + /// an element. + pub fn into_inner(self) -> Option<St> { + self.stream + } +} + +impl<St: Stream + Unpin> FusedFuture for StreamFuture<St> { + fn is_terminated(&self) -> bool { + self.stream.is_none() + } +} + +impl<St: Stream + Unpin> Future for StreamFuture<St> { + type Output = (Option<St::Item>, St); + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let item = { + let s = self.stream.as_mut().expect("polling StreamFuture twice"); + ready!(s.poll_next_unpin(cx)) + }; + let stream = self.stream.take().unwrap(); + Poll::Ready((item, stream)) + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/map.rs b/third_party/rust/futures-util/src/stream/stream/map.rs new file mode 100644 index 0000000000..88bb6129d4 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/map.rs @@ -0,0 +1,77 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +use crate::fns::FnMut1; + +pin_project! { + /// Stream for the [`map`](super::StreamExt::map) method. + #[must_use = "streams do nothing unless polled"] + pub struct Map<St, F> { + #[pin] + stream: St, + f: F, + } +} + +impl<St, F> fmt::Debug for Map<St, F> +where + St: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Map").field("stream", &self.stream).finish() + } +} + +impl<St, F> Map<St, F> { + pub(crate) fn new(stream: St, f: F) -> Self { + Self { stream, f } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, F> FusedStream for Map<St, F> +where + St: FusedStream, + F: FnMut1<St::Item>, +{ + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St, F> Stream for Map<St, F> +where + St: Stream, + F: FnMut1<St::Item>, +{ + type Item = F::Output; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + let res = ready!(this.stream.as_mut().poll_next(cx)); + Poll::Ready(res.map(|x| this.f.call_mut(x))) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.stream.size_hint() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<St, F, Item> Sink<Item> for Map<St, F> +where + St: Stream + Sink<Item>, + F: FnMut1<St::Item>, +{ + type Error = St::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/mod.rs b/third_party/rust/futures-util/src/stream/stream/mod.rs new file mode 100644 index 0000000000..bb5e24907d --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/mod.rs @@ -0,0 +1,1684 @@ +//! Streams +//! +//! This module contains a number of functions for working with `Stream`s, +//! including the `StreamExt` trait which adds methods to `Stream` types. + +use crate::future::{assert_future, Either}; +use crate::stream::assert_stream; +#[cfg(feature = "alloc")] +use alloc::boxed::Box; +#[cfg(feature = "alloc")] +use alloc::vec::Vec; +use core::pin::Pin; +#[cfg(feature = "sink")] +use futures_core::stream::TryStream; +#[cfg(feature = "alloc")] +use futures_core::stream::{BoxStream, LocalBoxStream}; +use futures_core::{ + future::Future, + stream::{FusedStream, Stream}, + task::{Context, Poll}, +}; +#[cfg(feature = "sink")] +use futures_sink::Sink; + +use crate::fns::{inspect_fn, InspectFn}; + +mod chain; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::chain::Chain; + +mod collect; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::collect::Collect; + +mod unzip; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::unzip::Unzip; + +mod concat; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::concat::Concat; + +mod count; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::count::Count; + +mod cycle; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::cycle::Cycle; + +mod enumerate; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::enumerate::Enumerate; + +mod filter; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::filter::Filter; + +mod filter_map; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::filter_map::FilterMap; + +mod flatten; + +delegate_all!( + /// Stream for the [`flatten`](StreamExt::flatten) method. + Flatten<St>( + flatten::Flatten<St, St::Item> + ): Debug + Sink + Stream + FusedStream + AccessInner[St, (.)] + New[|x: St| flatten::Flatten::new(x)] + where St: Stream +); + +mod fold; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::fold::Fold; + +mod any; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::any::Any; + +mod all; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::all::All; + +#[cfg(feature = "sink")] +mod forward; + +#[cfg(feature = "sink")] +delegate_all!( + /// Future for the [`forward`](super::StreamExt::forward) method. + #[cfg_attr(docsrs, doc(cfg(feature = "sink")))] + Forward<St, Si>( + forward::Forward<St, Si, St::Ok> + ): Debug + Future + FusedFuture + New[|x: St, y: Si| forward::Forward::new(x, y)] + where St: TryStream +); + +mod for_each; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::for_each::ForEach; + +mod fuse; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::fuse::Fuse; + +mod into_future; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::into_future::StreamFuture; + +delegate_all!( + /// Stream for the [`inspect`](StreamExt::inspect) method. + Inspect<St, F>( + map::Map<St, InspectFn<F>> + ): Debug + Sink + Stream + FusedStream + AccessInner[St, (.)] + New[|x: St, f: F| map::Map::new(x, inspect_fn(f))] +); + +mod map; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::map::Map; + +delegate_all!( + /// Stream for the [`flat_map`](StreamExt::flat_map) method. + FlatMap<St, U, F>( + flatten::Flatten<Map<St, F>, U> + ): Debug + Sink + Stream + FusedStream + AccessInner[St, (. .)] + New[|x: St, f: F| flatten::Flatten::new(Map::new(x, f))] +); + +mod next; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::next::Next; + +mod select_next_some; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::select_next_some::SelectNextSome; + +mod peek; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::peek::{NextIf, NextIfEq, Peek, PeekMut, Peekable}; + +mod skip; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::skip::Skip; + +mod skip_while; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::skip_while::SkipWhile; + +mod take; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::take::Take; + +mod take_while; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::take_while::TakeWhile; + +mod take_until; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::take_until::TakeUntil; + +mod then; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::then::Then; + +mod zip; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::zip::Zip; + +#[cfg(feature = "alloc")] +mod chunks; +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::chunks::Chunks; + +#[cfg(feature = "alloc")] +mod ready_chunks; +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::ready_chunks::ReadyChunks; + +mod scan; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::scan::Scan; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod buffer_unordered; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::buffer_unordered::BufferUnordered; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod buffered; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::buffered::Buffered; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod flatten_unordered; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] +pub use self::flatten_unordered::FlattenUnordered; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +delegate_all!( + /// Stream for the [`flat_map_unordered`](StreamExt::flat_map_unordered) method. + FlatMapUnordered<St, U, F>( + FlattenUnordered<Map<St, F>> + ): Debug + Sink + Stream + FusedStream + AccessInner[St, (. .)] + New[|x: St, limit: Option<usize>, f: F| FlattenUnordered::new(Map::new(x, f), limit)] + where St: Stream, U: Stream, U: Unpin, F: FnMut(St::Item) -> U +); + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod for_each_concurrent; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::for_each_concurrent::ForEachConcurrent; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +#[cfg(feature = "alloc")] +mod split; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "sink")] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::split::{ReuniteError, SplitSink, SplitStream}; + +#[cfg(feature = "std")] +mod catch_unwind; +#[cfg(feature = "std")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::catch_unwind::CatchUnwind; + +impl<T: ?Sized> StreamExt for T where T: Stream {} + +/// An extension trait for `Stream`s that provides a variety of convenient +/// combinator functions. +pub trait StreamExt: Stream { + /// Creates a future that resolves to the next item in the stream. + /// + /// Note that because `next` doesn't take ownership over the stream, + /// the [`Stream`] type must be [`Unpin`]. If you want to use `next` with a + /// [`!Unpin`](Unpin) stream, you'll first have to pin the stream. This can + /// be done by boxing the stream using [`Box::pin`] or + /// pinning it to the stack using the `pin_mut!` macro from the `pin_utils` + /// crate. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let mut stream = stream::iter(1..=3); + /// + /// assert_eq!(stream.next().await, Some(1)); + /// assert_eq!(stream.next().await, Some(2)); + /// assert_eq!(stream.next().await, Some(3)); + /// assert_eq!(stream.next().await, None); + /// # }); + /// ``` + fn next(&mut self) -> Next<'_, Self> + where + Self: Unpin, + { + assert_future::<Option<Self::Item>, _>(Next::new(self)) + } + + /// Converts this stream into a future of `(next_item, tail_of_stream)`. + /// If the stream terminates, then the next item is [`None`]. + /// + /// The returned future can be used to compose streams and futures together + /// by placing everything into the "world of futures". + /// + /// Note that because `into_future` moves the stream, the [`Stream`] type + /// must be [`Unpin`]. If you want to use `into_future` with a + /// [`!Unpin`](Unpin) stream, you'll first have to pin the stream. This can + /// be done by boxing the stream using [`Box::pin`] or + /// pinning it to the stack using the `pin_mut!` macro from the `pin_utils` + /// crate. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=3); + /// + /// let (item, stream) = stream.into_future().await; + /// assert_eq!(Some(1), item); + /// + /// let (item, stream) = stream.into_future().await; + /// assert_eq!(Some(2), item); + /// # }); + /// ``` + fn into_future(self) -> StreamFuture<Self> + where + Self: Sized + Unpin, + { + assert_future::<(Option<Self::Item>, Self), _>(StreamFuture::new(self)) + } + + /// Maps this stream's items to a different type, returning a new stream of + /// the resulting type. + /// + /// The provided closure is executed over all elements of this stream as + /// they are made available. It is executed inline with calls to + /// [`poll_next`](Stream::poll_next). + /// + /// Note that this function consumes the stream passed into it and returns a + /// wrapped version of it, similar to the existing `map` methods in the + /// standard library. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=3); + /// let stream = stream.map(|x| x + 3); + /// + /// assert_eq!(vec![4, 5, 6], stream.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn map<T, F>(self, f: F) -> Map<Self, F> + where + F: FnMut(Self::Item) -> T, + Self: Sized, + { + assert_stream::<T, _>(Map::new(self, f)) + } + + /// Creates a stream which gives the current iteration count as well as + /// the next value. + /// + /// The stream returned yields pairs `(i, val)`, where `i` is the + /// current index of iteration and `val` is the value returned by the + /// stream. + /// + /// `enumerate()` keeps its count as a [`usize`]. If you want to count by a + /// different sized integer, the [`zip`](StreamExt::zip) function provides similar + /// functionality. + /// + /// # Overflow Behavior + /// + /// The method does no guarding against overflows, so enumerating more than + /// [`prim@usize::max_value()`] elements either produces the wrong result or panics. If + /// debug assertions are enabled, a panic is guaranteed. + /// + /// # Panics + /// + /// The returned stream might panic if the to-be-returned index would + /// overflow a [`usize`]. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(vec!['a', 'b', 'c']); + /// + /// let mut stream = stream.enumerate(); + /// + /// assert_eq!(stream.next().await, Some((0, 'a'))); + /// assert_eq!(stream.next().await, Some((1, 'b'))); + /// assert_eq!(stream.next().await, Some((2, 'c'))); + /// assert_eq!(stream.next().await, None); + /// # }); + /// ``` + fn enumerate(self) -> Enumerate<Self> + where + Self: Sized, + { + assert_stream::<(usize, Self::Item), _>(Enumerate::new(self)) + } + + /// Filters the values produced by this stream according to the provided + /// asynchronous predicate. + /// + /// As values of this stream are made available, the provided predicate `f` + /// will be run against them. If the predicate returns a `Future` which + /// resolves to `true`, then the stream will yield the value, but if the + /// predicate returns a `Future` which resolves to `false`, then the value + /// will be discarded and the next value will be produced. + /// + /// Note that this function consumes the stream passed into it and returns a + /// wrapped version of it, similar to the existing `filter` methods in the + /// standard library. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=10); + /// let events = stream.filter(|x| future::ready(x % 2 == 0)); + /// + /// assert_eq!(vec![2, 4, 6, 8, 10], events.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn filter<Fut, F>(self, f: F) -> Filter<Self, Fut, F> + where + F: FnMut(&Self::Item) -> Fut, + Fut: Future<Output = bool>, + Self: Sized, + { + assert_stream::<Self::Item, _>(Filter::new(self, f)) + } + + /// Filters the values produced by this stream while simultaneously mapping + /// them to a different type according to the provided asynchronous closure. + /// + /// As values of this stream are made available, the provided function will + /// be run on them. If the future returned by the predicate `f` resolves to + /// [`Some(item)`](Some) then the stream will yield the value `item`, but if + /// it resolves to [`None`] then the next value will be produced. + /// + /// Note that this function consumes the stream passed into it and returns a + /// wrapped version of it, similar to the existing `filter_map` methods in + /// the standard library. + /// + /// # Examples + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=10); + /// let events = stream.filter_map(|x| async move { + /// if x % 2 == 0 { Some(x + 1) } else { None } + /// }); + /// + /// assert_eq!(vec![3, 5, 7, 9, 11], events.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn filter_map<Fut, T, F>(self, f: F) -> FilterMap<Self, Fut, F> + where + F: FnMut(Self::Item) -> Fut, + Fut: Future<Output = Option<T>>, + Self: Sized, + { + assert_stream::<T, _>(FilterMap::new(self, f)) + } + + /// Computes from this stream's items new items of a different type using + /// an asynchronous closure. + /// + /// The provided closure `f` will be called with an `Item` once a value is + /// ready, it returns a future which will then be run to completion + /// to produce the next value on this stream. + /// + /// Note that this function consumes the stream passed into it and returns a + /// wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=3); + /// let stream = stream.then(|x| async move { x + 3 }); + /// + /// assert_eq!(vec![4, 5, 6], stream.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F> + where + F: FnMut(Self::Item) -> Fut, + Fut: Future, + Self: Sized, + { + assert_stream::<Fut::Output, _>(Then::new(self, f)) + } + + /// Transforms a stream into a collection, returning a + /// future representing the result of that computation. + /// + /// The returned future will be resolved when the stream terminates. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::StreamExt; + /// use std::thread; + /// + /// let (tx, rx) = mpsc::unbounded(); + /// + /// thread::spawn(move || { + /// for i in 1..=5 { + /// tx.unbounded_send(i).unwrap(); + /// } + /// }); + /// + /// let output = rx.collect::<Vec<i32>>().await; + /// assert_eq!(output, vec![1, 2, 3, 4, 5]); + /// # }); + /// ``` + fn collect<C: Default + Extend<Self::Item>>(self) -> Collect<Self, C> + where + Self: Sized, + { + assert_future::<C, _>(Collect::new(self)) + } + + /// Converts a stream of pairs into a future, which + /// resolves to pair of containers. + /// + /// `unzip()` produces a future, which resolves to two + /// collections: one from the left elements of the pairs, + /// and one from the right elements. + /// + /// The returned future will be resolved when the stream terminates. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::StreamExt; + /// use std::thread; + /// + /// let (tx, rx) = mpsc::unbounded(); + /// + /// thread::spawn(move || { + /// tx.unbounded_send((1, 2)).unwrap(); + /// tx.unbounded_send((3, 4)).unwrap(); + /// tx.unbounded_send((5, 6)).unwrap(); + /// }); + /// + /// let (o1, o2): (Vec<_>, Vec<_>) = rx.unzip().await; + /// assert_eq!(o1, vec![1, 3, 5]); + /// assert_eq!(o2, vec![2, 4, 6]); + /// # }); + /// ``` + fn unzip<A, B, FromA, FromB>(self) -> Unzip<Self, FromA, FromB> + where + FromA: Default + Extend<A>, + FromB: Default + Extend<B>, + Self: Sized + Stream<Item = (A, B)>, + { + assert_future::<(FromA, FromB), _>(Unzip::new(self)) + } + + /// Concatenate all items of a stream into a single extendable + /// destination, returning a future representing the end result. + /// + /// This combinator will extend the first item with the contents + /// of all the subsequent results of the stream. If the stream is + /// empty, the default value will be returned. + /// + /// Works with all collections that implement the + /// [`Extend`](std::iter::Extend) trait. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::StreamExt; + /// use std::thread; + /// + /// let (tx, rx) = mpsc::unbounded(); + /// + /// thread::spawn(move || { + /// for i in (0..3).rev() { + /// let n = i * 3; + /// tx.unbounded_send(vec![n + 1, n + 2, n + 3]).unwrap(); + /// } + /// }); + /// + /// let result = rx.concat().await; + /// + /// assert_eq!(result, vec![7, 8, 9, 4, 5, 6, 1, 2, 3]); + /// # }); + /// ``` + fn concat(self) -> Concat<Self> + where + Self: Sized, + Self::Item: Extend<<<Self as Stream>::Item as IntoIterator>::Item> + IntoIterator + Default, + { + assert_future::<Self::Item, _>(Concat::new(self)) + } + + /// Drives the stream to completion, counting the number of items. + /// + /// # Overflow Behavior + /// + /// The method does no guarding against overflows, so counting elements of a + /// stream with more than [`usize::MAX`] elements either produces the wrong + /// result or panics. If debug assertions are enabled, a panic is guaranteed. + /// + /// # Panics + /// + /// This function might panic if the iterator has more than [`usize::MAX`] + /// elements. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=10); + /// let count = stream.count().await; + /// + /// assert_eq!(count, 10); + /// # }); + /// ``` + fn count(self) -> Count<Self> + where + Self: Sized, + { + assert_future::<usize, _>(Count::new(self)) + } + + /// Repeats a stream endlessly. + /// + /// The stream never terminates. Note that you likely want to avoid + /// usage of `collect` or such on the returned stream as it will exhaust + /// available memory as it tries to just fill up all RAM. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// let a = [1, 2, 3]; + /// let mut s = stream::iter(a.iter()).cycle(); + /// + /// assert_eq!(s.next().await, Some(&1)); + /// assert_eq!(s.next().await, Some(&2)); + /// assert_eq!(s.next().await, Some(&3)); + /// assert_eq!(s.next().await, Some(&1)); + /// assert_eq!(s.next().await, Some(&2)); + /// assert_eq!(s.next().await, Some(&3)); + /// assert_eq!(s.next().await, Some(&1)); + /// # }); + /// ``` + fn cycle(self) -> Cycle<Self> + where + Self: Sized + Clone, + { + assert_stream::<Self::Item, _>(Cycle::new(self)) + } + + /// Execute an accumulating asynchronous computation over a stream, + /// collecting all the values into one final result. + /// + /// This combinator will accumulate all values returned by this stream + /// according to the closure provided. The initial state is also provided to + /// this method and then is returned again by each execution of the closure. + /// Once the entire stream has been exhausted the returned future will + /// resolve to this value. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let number_stream = stream::iter(0..6); + /// let sum = number_stream.fold(0, |acc, x| async move { acc + x }); + /// assert_eq!(sum.await, 15); + /// # }); + /// ``` + fn fold<T, Fut, F>(self, init: T, f: F) -> Fold<Self, Fut, T, F> + where + F: FnMut(T, Self::Item) -> Fut, + Fut: Future<Output = T>, + Self: Sized, + { + assert_future::<T, _>(Fold::new(self, f, init)) + } + + /// Execute predicate over asynchronous stream, and return `true` if any element in stream satisfied a predicate. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let number_stream = stream::iter(0..10); + /// let contain_three = number_stream.any(|i| async move { i == 3 }); + /// assert_eq!(contain_three.await, true); + /// # }); + /// ``` + fn any<Fut, F>(self, f: F) -> Any<Self, Fut, F> + where + F: FnMut(Self::Item) -> Fut, + Fut: Future<Output = bool>, + Self: Sized, + { + assert_future::<bool, _>(Any::new(self, f)) + } + + /// Execute predicate over asynchronous stream, and return `true` if all element in stream satisfied a predicate. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let number_stream = stream::iter(0..10); + /// let less_then_twenty = number_stream.all(|i| async move { i < 20 }); + /// assert_eq!(less_then_twenty.await, true); + /// # }); + /// ``` + fn all<Fut, F>(self, f: F) -> All<Self, Fut, F> + where + F: FnMut(Self::Item) -> Fut, + Fut: Future<Output = bool>, + Self: Sized, + { + assert_future::<bool, _>(All::new(self, f)) + } + + /// Flattens a stream of streams into just one continuous stream. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::StreamExt; + /// use std::thread; + /// + /// let (tx1, rx1) = mpsc::unbounded(); + /// let (tx2, rx2) = mpsc::unbounded(); + /// let (tx3, rx3) = mpsc::unbounded(); + /// + /// thread::spawn(move || { + /// tx1.unbounded_send(1).unwrap(); + /// tx1.unbounded_send(2).unwrap(); + /// }); + /// thread::spawn(move || { + /// tx2.unbounded_send(3).unwrap(); + /// tx2.unbounded_send(4).unwrap(); + /// }); + /// thread::spawn(move || { + /// tx3.unbounded_send(rx1).unwrap(); + /// tx3.unbounded_send(rx2).unwrap(); + /// }); + /// + /// let output = rx3.flatten().collect::<Vec<i32>>().await; + /// assert_eq!(output, vec![1, 2, 3, 4]); + /// # }); + /// ``` + fn flatten(self) -> Flatten<Self> + where + Self::Item: Stream, + Self: Sized, + { + assert_stream::<<Self::Item as Stream>::Item, _>(Flatten::new(self)) + } + + /// Flattens a stream of streams into just one continuous stream. Polls + /// inner streams concurrently. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::StreamExt; + /// use std::thread; + /// + /// let (tx1, rx1) = mpsc::unbounded(); + /// let (tx2, rx2) = mpsc::unbounded(); + /// let (tx3, rx3) = mpsc::unbounded(); + /// + /// thread::spawn(move || { + /// tx1.unbounded_send(1).unwrap(); + /// tx1.unbounded_send(2).unwrap(); + /// }); + /// thread::spawn(move || { + /// tx2.unbounded_send(3).unwrap(); + /// tx2.unbounded_send(4).unwrap(); + /// }); + /// thread::spawn(move || { + /// tx3.unbounded_send(rx1).unwrap(); + /// tx3.unbounded_send(rx2).unwrap(); + /// }); + /// + /// let mut output = rx3.flatten_unordered(None).collect::<Vec<i32>>().await; + /// output.sort(); + /// + /// assert_eq!(output, vec![1, 2, 3, 4]); + /// # }); + /// ``` + #[cfg(not(futures_no_atomic_cas))] + #[cfg(feature = "alloc")] + fn flatten_unordered(self, limit: impl Into<Option<usize>>) -> FlattenUnordered<Self> + where + Self::Item: Stream + Unpin, + Self: Sized, + { + FlattenUnordered::new(self, limit.into()) + } + + /// Maps a stream like [`StreamExt::map`] but flattens nested `Stream`s. + /// + /// [`StreamExt::map`] is very useful, but if it produces a `Stream` instead, + /// you would have to chain combinators like `.map(f).flatten()` while this + /// combinator provides ability to write `.flat_map(f)` instead of chaining. + /// + /// The provided closure which produces inner streams is executed over all elements + /// of stream as last inner stream is terminated and next stream item is available. + /// + /// Note that this function consumes the stream passed into it and returns a + /// wrapped version of it, similar to the existing `flat_map` methods in the + /// standard library. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=3); + /// let stream = stream.flat_map(|x| stream::iter(vec![x + 3; x])); + /// + /// assert_eq!(vec![4, 5, 5, 6, 6, 6], stream.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> + where + F: FnMut(Self::Item) -> U, + U: Stream, + Self: Sized, + { + assert_stream::<U::Item, _>(FlatMap::new(self, f)) + } + + /// Maps a stream like [`StreamExt::map`] but flattens nested `Stream`s + /// and polls them concurrently, yielding items in any order, as they made + /// available. + /// + /// [`StreamExt::map`] is very useful, but if it produces `Stream`s + /// instead, and you need to poll all of them concurrently, you would + /// have to use something like `for_each_concurrent` and merge values + /// by hand. This combinator provides ability to collect all values + /// from concurrently polled streams into one stream. + /// + /// The first argument is an optional limit on the number of concurrently + /// polled streams. If this limit is not `None`, no more than `limit` streams + /// will be polled concurrently. The `limit` argument is of type + /// `Into<Option<usize>>`, and so can be provided as either `None`, + /// `Some(10)`, or just `10`. Note: a limit of zero is interpreted as + /// no limit at all, and will have the same result as passing in `None`. + /// + /// The provided closure which produces inner streams is executed over + /// all elements of stream as next stream item is available and limit + /// of concurrently processed streams isn't exceeded. + /// + /// Note that this function consumes the stream passed into it and + /// returns a wrapped version of it. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..5); + /// let stream = stream.flat_map_unordered(1, |x| stream::iter(vec![x; x])); + /// let mut values = stream.collect::<Vec<_>>().await; + /// values.sort(); + /// + /// assert_eq!(vec![1usize, 2, 2, 3, 3, 3, 4, 4, 4, 4], values); + /// # }); + /// ``` + #[cfg(not(futures_no_atomic_cas))] + #[cfg(feature = "alloc")] + fn flat_map_unordered<U, F>( + self, + limit: impl Into<Option<usize>>, + f: F, + ) -> FlatMapUnordered<Self, U, F> + where + U: Stream + Unpin, + F: FnMut(Self::Item) -> U, + Self: Sized, + { + FlatMapUnordered::new(self, limit.into(), f) + } + + /// Combinator similar to [`StreamExt::fold`] that holds internal state + /// and produces a new stream. + /// + /// Accepts initial state and closure which will be applied to each element + /// of the stream until provided closure returns `None`. Once `None` is + /// returned, stream will be terminated. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=10); + /// + /// let stream = stream.scan(0, |state, x| { + /// *state += x; + /// future::ready(if *state < 10 { Some(x) } else { None }) + /// }); + /// + /// assert_eq!(vec![1, 2, 3], stream.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn scan<S, B, Fut, F>(self, initial_state: S, f: F) -> Scan<Self, S, Fut, F> + where + F: FnMut(&mut S, Self::Item) -> Fut, + Fut: Future<Output = Option<B>>, + Self: Sized, + { + assert_stream::<B, _>(Scan::new(self, initial_state, f)) + } + + /// Skip elements on this stream while the provided asynchronous predicate + /// resolves to `true`. + /// + /// This function, like `Iterator::skip_while`, will skip elements on the + /// stream until the predicate `f` resolves to `false`. Once one element + /// returns `false`, all future elements will be returned from the underlying + /// stream. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=10); + /// + /// let stream = stream.skip_while(|x| future::ready(*x <= 5)); + /// + /// assert_eq!(vec![6, 7, 8, 9, 10], stream.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn skip_while<Fut, F>(self, f: F) -> SkipWhile<Self, Fut, F> + where + F: FnMut(&Self::Item) -> Fut, + Fut: Future<Output = bool>, + Self: Sized, + { + assert_stream::<Self::Item, _>(SkipWhile::new(self, f)) + } + + /// Take elements from this stream while the provided asynchronous predicate + /// resolves to `true`. + /// + /// This function, like `Iterator::take_while`, will take elements from the + /// stream until the predicate `f` resolves to `false`. Once one element + /// returns `false`, it will always return that the stream is done. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=10); + /// + /// let stream = stream.take_while(|x| future::ready(*x <= 5)); + /// + /// assert_eq!(vec![1, 2, 3, 4, 5], stream.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn take_while<Fut, F>(self, f: F) -> TakeWhile<Self, Fut, F> + where + F: FnMut(&Self::Item) -> Fut, + Fut: Future<Output = bool>, + Self: Sized, + { + assert_stream::<Self::Item, _>(TakeWhile::new(self, f)) + } + + /// Take elements from this stream until the provided future resolves. + /// + /// This function will take elements from the stream until the provided + /// stopping future `fut` resolves. Once the `fut` future becomes ready, + /// this stream combinator will always return that the stream is done. + /// + /// The stopping future may return any type. Once the stream is stopped + /// the result of the stopping future may be accessed with `TakeUntil::take_result()`. + /// The stream may also be resumed with `TakeUntil::take_future()`. + /// See the documentation of [`TakeUntil`] for more information. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt}; + /// use futures::task::Poll; + /// + /// let stream = stream::iter(1..=10); + /// + /// let mut i = 0; + /// let stop_fut = future::poll_fn(|_cx| { + /// i += 1; + /// if i <= 5 { + /// Poll::Pending + /// } else { + /// Poll::Ready(()) + /// } + /// }); + /// + /// let stream = stream.take_until(stop_fut); + /// + /// assert_eq!(vec![1, 2, 3, 4, 5], stream.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn take_until<Fut>(self, fut: Fut) -> TakeUntil<Self, Fut> + where + Fut: Future, + Self: Sized, + { + assert_stream::<Self::Item, _>(TakeUntil::new(self, fut)) + } + + /// Runs this stream to completion, executing the provided asynchronous + /// closure for each element on the stream. + /// + /// The closure provided will be called for each item this stream produces, + /// yielding a future. That future will then be executed to completion + /// before moving on to the next item. + /// + /// The returned value is a `Future` where the `Output` type is `()`; it is + /// executed entirely for its side effects. + /// + /// To process each item in the stream and produce another stream instead + /// of a single future, use `then` instead. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt}; + /// + /// let mut x = 0; + /// + /// { + /// let fut = stream::repeat(1).take(3).for_each(|item| { + /// x += item; + /// future::ready(()) + /// }); + /// fut.await; + /// } + /// + /// assert_eq!(x, 3); + /// # }); + /// ``` + fn for_each<Fut, F>(self, f: F) -> ForEach<Self, Fut, F> + where + F: FnMut(Self::Item) -> Fut, + Fut: Future<Output = ()>, + Self: Sized, + { + assert_future::<(), _>(ForEach::new(self, f)) + } + + /// Runs this stream to completion, executing the provided asynchronous + /// closure for each element on the stream concurrently as elements become + /// available. + /// + /// This is similar to [`StreamExt::for_each`], but the futures + /// produced by the closure are run concurrently (but not in parallel-- + /// this combinator does not introduce any threads). + /// + /// The closure provided will be called for each item this stream produces, + /// yielding a future. That future will then be executed to completion + /// concurrently with the other futures produced by the closure. + /// + /// The first argument is an optional limit on the number of concurrent + /// futures. If this limit is not `None`, no more than `limit` futures + /// will be run concurrently. The `limit` argument is of type + /// `Into<Option<usize>>`, and so can be provided as either `None`, + /// `Some(10)`, or just `10`. Note: a limit of zero is interpreted as + /// no limit at all, and will have the same result as passing in `None`. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::oneshot; + /// use futures::stream::{self, StreamExt}; + /// + /// let (tx1, rx1) = oneshot::channel(); + /// let (tx2, rx2) = oneshot::channel(); + /// let (tx3, rx3) = oneshot::channel(); + /// + /// let fut = stream::iter(vec![rx1, rx2, rx3]).for_each_concurrent( + /// /* limit */ 2, + /// |rx| async move { + /// rx.await.unwrap(); + /// } + /// ); + /// tx1.send(()).unwrap(); + /// tx2.send(()).unwrap(); + /// tx3.send(()).unwrap(); + /// fut.await; + /// # }) + /// ``` + #[cfg(not(futures_no_atomic_cas))] + #[cfg(feature = "alloc")] + fn for_each_concurrent<Fut, F>( + self, + limit: impl Into<Option<usize>>, + f: F, + ) -> ForEachConcurrent<Self, Fut, F> + where + F: FnMut(Self::Item) -> Fut, + Fut: Future<Output = ()>, + Self: Sized, + { + assert_future::<(), _>(ForEachConcurrent::new(self, limit.into(), f)) + } + + /// Creates a new stream of at most `n` items of the underlying stream. + /// + /// Once `n` items have been yielded from this stream then it will always + /// return that the stream is done. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=10).take(3); + /// + /// assert_eq!(vec![1, 2, 3], stream.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn take(self, n: usize) -> Take<Self> + where + Self: Sized, + { + assert_stream::<Self::Item, _>(Take::new(self, n)) + } + + /// Creates a new stream which skips `n` items of the underlying stream. + /// + /// Once `n` items have been skipped from this stream then it will always + /// return the remaining items on this stream. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(1..=10).skip(5); + /// + /// assert_eq!(vec![6, 7, 8, 9, 10], stream.collect::<Vec<_>>().await); + /// # }); + /// ``` + fn skip(self, n: usize) -> Skip<Self> + where + Self: Sized, + { + assert_stream::<Self::Item, _>(Skip::new(self, n)) + } + + /// Fuse a stream such that [`poll_next`](Stream::poll_next) will never + /// again be called once it has finished. This method can be used to turn + /// any `Stream` into a `FusedStream`. + /// + /// Normally, once a stream has returned [`None`] from + /// [`poll_next`](Stream::poll_next) any further calls could exhibit bad + /// behavior such as block forever, panic, never return, etc. If it is known + /// that [`poll_next`](Stream::poll_next) may be called after stream + /// has already finished, then this method can be used to ensure that it has + /// defined semantics. + /// + /// The [`poll_next`](Stream::poll_next) method of a `fuse`d stream + /// is guaranteed to return [`None`] after the underlying stream has + /// finished. + /// + /// # Examples + /// + /// ``` + /// use futures::executor::block_on_stream; + /// use futures::stream::{self, StreamExt}; + /// use futures::task::Poll; + /// + /// let mut x = 0; + /// let stream = stream::poll_fn(|_| { + /// x += 1; + /// match x { + /// 0..=2 => Poll::Ready(Some(x)), + /// 3 => Poll::Ready(None), + /// _ => panic!("should not happen") + /// } + /// }).fuse(); + /// + /// let mut iter = block_on_stream(stream); + /// assert_eq!(Some(1), iter.next()); + /// assert_eq!(Some(2), iter.next()); + /// assert_eq!(None, iter.next()); + /// assert_eq!(None, iter.next()); + /// // ... + /// ``` + fn fuse(self) -> Fuse<Self> + where + Self: Sized, + { + assert_stream::<Self::Item, _>(Fuse::new(self)) + } + + /// Borrows a stream, rather than consuming it. + /// + /// This is useful to allow applying stream adaptors while still retaining + /// ownership of the original stream. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let mut stream = stream::iter(1..5); + /// + /// let sum = stream.by_ref() + /// .take(2) + /// .fold(0, |a, b| async move { a + b }) + /// .await; + /// assert_eq!(sum, 3); + /// + /// // You can use the stream again + /// let sum = stream.take(2) + /// .fold(0, |a, b| async move { a + b }) + /// .await; + /// assert_eq!(sum, 7); + /// # }); + /// ``` + fn by_ref(&mut self) -> &mut Self { + self + } + + /// Catches unwinding panics while polling the stream. + /// + /// Caught panic (if any) will be the last element of the resulting stream. + /// + /// In general, panics within a stream can propagate all the way out to the + /// task level. This combinator makes it possible to halt unwinding within + /// the stream itself. It's most commonly used within task executors. This + /// method should not be used for error handling. + /// + /// Note that this method requires the `UnwindSafe` bound from the standard + /// library. This isn't always applied automatically, and the standard + /// library provides an `AssertUnwindSafe` wrapper type to apply it + /// after-the fact. To assist using this method, the [`Stream`] trait is + /// also implemented for `AssertUnwindSafe<St>` where `St` implements + /// [`Stream`]. + /// + /// This method is only available when the `std` feature of this + /// library is activated, and it is activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream = stream::iter(vec![Some(10), None, Some(11)]); + /// // Panic on second element + /// let stream_panicking = stream.map(|o| o.unwrap()); + /// // Collect all the results + /// let stream = stream_panicking.catch_unwind(); + /// + /// let results: Vec<Result<i32, _>> = stream.collect().await; + /// match results[0] { + /// Ok(10) => {} + /// _ => panic!("unexpected result!"), + /// } + /// assert!(results[1].is_err()); + /// assert_eq!(results.len(), 2); + /// # }); + /// ``` + #[cfg(feature = "std")] + fn catch_unwind(self) -> CatchUnwind<Self> + where + Self: Sized + std::panic::UnwindSafe, + { + assert_stream(CatchUnwind::new(self)) + } + + /// Wrap the stream in a Box, pinning it. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + #[cfg(feature = "alloc")] + fn boxed<'a>(self) -> BoxStream<'a, Self::Item> + where + Self: Sized + Send + 'a, + { + assert_stream::<Self::Item, _>(Box::pin(self)) + } + + /// Wrap the stream in a Box, pinning it. + /// + /// Similar to `boxed`, but without the `Send` requirement. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + #[cfg(feature = "alloc")] + fn boxed_local<'a>(self) -> LocalBoxStream<'a, Self::Item> + where + Self: Sized + 'a, + { + assert_stream::<Self::Item, _>(Box::pin(self)) + } + + /// An adaptor for creating a buffered list of pending futures. + /// + /// If this stream's item can be converted into a future, then this adaptor + /// will buffer up to at most `n` futures and then return the outputs in the + /// same order as the underlying stream. No more than `n` futures will be + /// buffered at any point in time, and less than `n` may also be buffered + /// depending on the state of each future. + /// + /// The returned stream will be a stream of each future's output. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + #[cfg(not(futures_no_atomic_cas))] + #[cfg(feature = "alloc")] + fn buffered(self, n: usize) -> Buffered<Self> + where + Self::Item: Future, + Self: Sized, + { + assert_stream::<<Self::Item as Future>::Output, _>(Buffered::new(self, n)) + } + + /// An adaptor for creating a buffered list of pending futures (unordered). + /// + /// If this stream's item can be converted into a future, then this adaptor + /// will buffer up to `n` futures and then return the outputs in the order + /// in which they complete. No more than `n` futures will be buffered at + /// any point in time, and less than `n` may also be buffered depending on + /// the state of each future. + /// + /// The returned stream will be a stream of each future's output. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::oneshot; + /// use futures::stream::{self, StreamExt}; + /// + /// let (send_one, recv_one) = oneshot::channel(); + /// let (send_two, recv_two) = oneshot::channel(); + /// + /// let stream_of_futures = stream::iter(vec![recv_one, recv_two]); + /// let mut buffered = stream_of_futures.buffer_unordered(10); + /// + /// send_two.send(2i32)?; + /// assert_eq!(buffered.next().await, Some(Ok(2i32))); + /// + /// send_one.send(1i32)?; + /// assert_eq!(buffered.next().await, Some(Ok(1i32))); + /// + /// assert_eq!(buffered.next().await, None); + /// # Ok::<(), i32>(()) }).unwrap(); + /// ``` + #[cfg(not(futures_no_atomic_cas))] + #[cfg(feature = "alloc")] + fn buffer_unordered(self, n: usize) -> BufferUnordered<Self> + where + Self::Item: Future, + Self: Sized, + { + assert_stream::<<Self::Item as Future>::Output, _>(BufferUnordered::new(self, n)) + } + + /// An adapter for zipping two streams together. + /// + /// The zipped stream waits for both streams to produce an item, and then + /// returns that pair. If either stream ends then the zipped stream will + /// also end. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream1 = stream::iter(1..=3); + /// let stream2 = stream::iter(5..=10); + /// + /// let vec = stream1.zip(stream2) + /// .collect::<Vec<_>>() + /// .await; + /// assert_eq!(vec![(1, 5), (2, 6), (3, 7)], vec); + /// # }); + /// ``` + /// + fn zip<St>(self, other: St) -> Zip<Self, St> + where + St: Stream, + Self: Sized, + { + assert_stream::<(Self::Item, St::Item), _>(Zip::new(self, other)) + } + + /// Adapter for chaining two streams. + /// + /// The resulting stream emits elements from the first stream, and when + /// first stream reaches the end, emits the elements from the second stream. + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// + /// let stream1 = stream::iter(vec![Ok(10), Err(false)]); + /// let stream2 = stream::iter(vec![Err(true), Ok(20)]); + /// + /// let stream = stream1.chain(stream2); + /// + /// let result: Vec<_> = stream.collect().await; + /// assert_eq!(result, vec![ + /// Ok(10), + /// Err(false), + /// Err(true), + /// Ok(20), + /// ]); + /// # }); + /// ``` + fn chain<St>(self, other: St) -> Chain<Self, St> + where + St: Stream<Item = Self::Item>, + Self: Sized, + { + assert_stream::<Self::Item, _>(Chain::new(self, other)) + } + + /// Creates a new stream which exposes a `peek` method. + /// + /// Calling `peek` returns a reference to the next item in the stream. + fn peekable(self) -> Peekable<Self> + where + Self: Sized, + { + assert_stream::<Self::Item, _>(Peekable::new(self)) + } + + /// An adaptor for chunking up items of the stream inside a vector. + /// + /// This combinator will attempt to pull items from this stream and buffer + /// them into a local vector. At most `capacity` items will get buffered + /// before they're yielded from the returned stream. + /// + /// Note that the vectors returned from this iterator may not always have + /// `capacity` elements. If the underlying stream ended and only a partial + /// vector was created, it'll be returned. Additionally if an error happens + /// from the underlying stream then the currently buffered items will be + /// yielded. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + /// + /// # Panics + /// + /// This method will panic if `capacity` is zero. + #[cfg(feature = "alloc")] + fn chunks(self, capacity: usize) -> Chunks<Self> + where + Self: Sized, + { + assert_stream::<Vec<Self::Item>, _>(Chunks::new(self, capacity)) + } + + /// An adaptor for chunking up ready items of the stream inside a vector. + /// + /// This combinator will attempt to pull ready items from this stream and + /// buffer them into a local vector. At most `capacity` items will get + /// buffered before they're yielded from the returned stream. If underlying + /// stream returns `Poll::Pending`, and collected chunk is not empty, it will + /// be immediately returned. + /// + /// If the underlying stream ended and only a partial vector was created, + /// it will be returned. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + /// + /// # Panics + /// + /// This method will panic if `capacity` is zero. + #[cfg(feature = "alloc")] + fn ready_chunks(self, capacity: usize) -> ReadyChunks<Self> + where + Self: Sized, + { + assert_stream::<Vec<Self::Item>, _>(ReadyChunks::new(self, capacity)) + } + + /// A future that completes after the given stream has been fully processed + /// into the sink and the sink has been flushed and closed. + /// + /// This future will drive the stream to keep producing items until it is + /// exhausted, sending each item to the sink. It will complete once the + /// stream is exhausted, the sink has received and flushed all items, and + /// the sink is closed. Note that neither the original stream nor provided + /// sink will be output by this future. Pass the sink by `Pin<&mut S>` + /// (for example, via `forward(&mut sink)` inside an `async` fn/block) in + /// order to preserve access to the `Sink`. If the stream produces an error, + /// that error will be returned by this future without flushing/closing the sink. + #[cfg(feature = "sink")] + #[cfg_attr(docsrs, doc(cfg(feature = "sink")))] + fn forward<S>(self, sink: S) -> Forward<Self, S> + where + S: Sink<Self::Ok, Error = Self::Error>, + Self: TryStream + Sized, + // Self: TryStream + Sized + Stream<Item = Result<<Self as TryStream>::Ok, <Self as TryStream>::Error>>, + { + // TODO: type mismatch resolving `<Self as futures_core::Stream>::Item == std::result::Result<<Self as futures_core::TryStream>::Ok, <Self as futures_core::TryStream>::Error>` + // assert_future::<Result<(), Self::Error>, _>(Forward::new(self, sink)) + Forward::new(self, sink) + } + + /// Splits this `Stream + Sink` object into separate `Sink` and `Stream` + /// objects. + /// + /// This can be useful when you want to split ownership between tasks, or + /// allow direct interaction between the two objects (e.g. via + /// `Sink::send_all`). + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + #[cfg(feature = "sink")] + #[cfg_attr(docsrs, doc(cfg(feature = "sink")))] + #[cfg(not(futures_no_atomic_cas))] + #[cfg(feature = "alloc")] + fn split<Item>(self) -> (SplitSink<Self, Item>, SplitStream<Self>) + where + Self: Sink<Item> + Sized, + { + let (sink, stream) = split::split(self); + ( + crate::sink::assert_sink::<Item, Self::Error, _>(sink), + assert_stream::<Self::Item, _>(stream), + ) + } + + /// Do something with each item of this stream, afterwards passing it on. + /// + /// This is similar to the `Iterator::inspect` method in the standard + /// library where it allows easily inspecting each value as it passes + /// through the stream, for example to debug what's going on. + fn inspect<F>(self, f: F) -> Inspect<Self, F> + where + F: FnMut(&Self::Item), + Self: Sized, + { + assert_stream::<Self::Item, _>(Inspect::new(self, f)) + } + + /// Wrap this stream in an `Either` stream, making it the left-hand variant + /// of that `Either`. + /// + /// This can be used in combination with the `right_stream` method to write `if` + /// statements that evaluate to different streams in different branches. + fn left_stream<B>(self) -> Either<Self, B> + where + B: Stream<Item = Self::Item>, + Self: Sized, + { + assert_stream::<Self::Item, _>(Either::Left(self)) + } + + /// Wrap this stream in an `Either` stream, making it the right-hand variant + /// of that `Either`. + /// + /// This can be used in combination with the `left_stream` method to write `if` + /// statements that evaluate to different streams in different branches. + fn right_stream<B>(self) -> Either<B, Self> + where + B: Stream<Item = Self::Item>, + Self: Sized, + { + assert_stream::<Self::Item, _>(Either::Right(self)) + } + + /// A convenience method for calling [`Stream::poll_next`] on [`Unpin`] + /// stream types. + fn poll_next_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> + where + Self: Unpin, + { + Pin::new(self).poll_next(cx) + } + + /// Returns a [`Future`] that resolves when the next item in this stream is + /// ready. + /// + /// This is similar to the [`next`][StreamExt::next] method, but it won't + /// resolve to [`None`] if used on an empty [`Stream`]. Instead, the + /// returned future type will return `true` from + /// [`FusedFuture::is_terminated`][] when the [`Stream`] is empty, allowing + /// [`select_next_some`][StreamExt::select_next_some] to be easily used with + /// the [`select!`] macro. + /// + /// If the future is polled after this [`Stream`] is empty it will panic. + /// Using the future with a [`FusedFuture`][]-aware primitive like the + /// [`select!`] macro will prevent this. + /// + /// [`FusedFuture`]: futures_core::future::FusedFuture + /// [`FusedFuture::is_terminated`]: futures_core::future::FusedFuture::is_terminated + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::{future, select}; + /// use futures::stream::{StreamExt, FuturesUnordered}; + /// + /// let mut fut = future::ready(1); + /// let mut async_tasks = FuturesUnordered::new(); + /// let mut total = 0; + /// loop { + /// select! { + /// num = fut => { + /// // First, the `ready` future completes. + /// total += num; + /// // Then we spawn a new task onto `async_tasks`, + /// async_tasks.push(async { 5 }); + /// }, + /// // On the next iteration of the loop, the task we spawned + /// // completes. + /// num = async_tasks.select_next_some() => { + /// total += num; + /// } + /// // Finally, both the `ready` future and `async_tasks` have + /// // finished, so we enter the `complete` branch. + /// complete => break, + /// } + /// } + /// assert_eq!(total, 6); + /// # }); + /// ``` + /// + /// [`select!`]: crate::select + fn select_next_some(&mut self) -> SelectNextSome<'_, Self> + where + Self: Unpin + FusedStream, + { + assert_future::<Self::Item, _>(SelectNextSome::new(self)) + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/next.rs b/third_party/rust/futures-util/src/stream/stream/next.rs new file mode 100644 index 0000000000..8d8347aa03 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/next.rs @@ -0,0 +1,34 @@ +use crate::stream::StreamExt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; + +/// Future for the [`next`](super::StreamExt::next) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct Next<'a, St: ?Sized> { + stream: &'a mut St, +} + +impl<St: ?Sized + Unpin> Unpin for Next<'_, St> {} + +impl<'a, St: ?Sized + Stream + Unpin> Next<'a, St> { + pub(super) fn new(stream: &'a mut St) -> Self { + Self { stream } + } +} + +impl<St: ?Sized + FusedStream + Unpin> FusedFuture for Next<'_, St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St: ?Sized + Stream + Unpin> Future for Next<'_, St> { + type Output = Option<St::Item>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + self.stream.poll_next_unpin(cx) + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/peek.rs b/third_party/rust/futures-util/src/stream/stream/peek.rs new file mode 100644 index 0000000000..ea3d6243f3 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/peek.rs @@ -0,0 +1,433 @@ +use crate::fns::FnOnce1; +use crate::stream::{Fuse, StreamExt}; +use core::fmt; +use core::marker::PhantomData; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// A `Stream` that implements a `peek` method. + /// + /// The `peek` method can be used to retrieve a reference + /// to the next `Stream::Item` if available. A subsequent + /// call to `poll` will return the owned item. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Peekable<St: Stream> { + #[pin] + stream: Fuse<St>, + peeked: Option<St::Item>, + } +} + +impl<St: Stream> Peekable<St> { + pub(super) fn new(stream: St) -> Self { + Self { stream: stream.fuse(), peeked: None } + } + + delegate_access_inner!(stream, St, (.)); + + /// Produces a future which retrieves a reference to the next item + /// in the stream, or `None` if the underlying stream terminates. + pub fn peek(self: Pin<&mut Self>) -> Peek<'_, St> { + Peek { inner: Some(self) } + } + + /// Peek retrieves a reference to the next item in the stream. + /// + /// This method polls the underlying stream and return either a reference + /// to the next item if the stream is ready or passes through any errors. + pub fn poll_peek(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<&St::Item>> { + let mut this = self.project(); + + Poll::Ready(loop { + if this.peeked.is_some() { + break this.peeked.as_ref(); + } else if let Some(item) = ready!(this.stream.as_mut().poll_next(cx)) { + *this.peeked = Some(item); + } else { + break None; + } + }) + } + + /// Produces a future which retrieves a mutable reference to the next item + /// in the stream, or `None` if the underlying stream terminates. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// use futures::pin_mut; + /// + /// let stream = stream::iter(vec![1, 2, 3]).peekable(); + /// pin_mut!(stream); + /// + /// assert_eq!(stream.as_mut().peek_mut().await, Some(&mut 1)); + /// assert_eq!(stream.as_mut().next().await, Some(1)); + /// + /// // Peek into the stream and modify the value which will be returned next + /// if let Some(p) = stream.as_mut().peek_mut().await { + /// if *p == 2 { + /// *p = 5; + /// } + /// } + /// + /// assert_eq!(stream.collect::<Vec<_>>().await, vec![5, 3]); + /// # }); + /// ``` + pub fn peek_mut(self: Pin<&mut Self>) -> PeekMut<'_, St> { + PeekMut { inner: Some(self) } + } + + /// Peek retrieves a mutable reference to the next item in the stream. + pub fn poll_peek_mut( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> Poll<Option<&mut St::Item>> { + let mut this = self.project(); + + Poll::Ready(loop { + if this.peeked.is_some() { + break this.peeked.as_mut(); + } else if let Some(item) = ready!(this.stream.as_mut().poll_next(cx)) { + *this.peeked = Some(item); + } else { + break None; + } + }) + } + + /// Creates a future which will consume and return the next value of this + /// stream if a condition is true. + /// + /// If `func` returns `true` for the next value of this stream, consume and + /// return it. Otherwise, return `None`. + /// + /// # Examples + /// + /// Consume a number if it's equal to 0. + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// use futures::pin_mut; + /// + /// let stream = stream::iter(0..5).peekable(); + /// pin_mut!(stream); + /// // The first item of the stream is 0; consume it. + /// assert_eq!(stream.as_mut().next_if(|&x| x == 0).await, Some(0)); + /// // The next item returned is now 1, so `consume` will return `false`. + /// assert_eq!(stream.as_mut().next_if(|&x| x == 0).await, None); + /// // `next_if` saves the value of the next item if it was not equal to `expected`. + /// assert_eq!(stream.next().await, Some(1)); + /// # }); + /// ``` + /// + /// Consume any number less than 10. + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// use futures::pin_mut; + /// + /// let stream = stream::iter(1..20).peekable(); + /// pin_mut!(stream); + /// // Consume all numbers less than 10 + /// while stream.as_mut().next_if(|&x| x < 10).await.is_some() {} + /// // The next value returned will be 10 + /// assert_eq!(stream.next().await, Some(10)); + /// # }); + /// ``` + pub fn next_if<F>(self: Pin<&mut Self>, func: F) -> NextIf<'_, St, F> + where + F: FnOnce(&St::Item) -> bool, + { + NextIf { inner: Some((self, func)) } + } + + /// Creates a future which will consume and return the next item if it is + /// equal to `expected`. + /// + /// # Example + /// + /// Consume a number if it's equal to 0. + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt}; + /// use futures::pin_mut; + /// + /// let stream = stream::iter(0..5).peekable(); + /// pin_mut!(stream); + /// // The first item of the stream is 0; consume it. + /// assert_eq!(stream.as_mut().next_if_eq(&0).await, Some(0)); + /// // The next item returned is now 1, so `consume` will return `false`. + /// assert_eq!(stream.as_mut().next_if_eq(&0).await, None); + /// // `next_if_eq` saves the value of the next item if it was not equal to `expected`. + /// assert_eq!(stream.next().await, Some(1)); + /// # }); + /// ``` + pub fn next_if_eq<'a, T>(self: Pin<&'a mut Self>, expected: &'a T) -> NextIfEq<'a, St, T> + where + T: ?Sized, + St::Item: PartialEq<T>, + { + NextIfEq { + inner: NextIf { inner: Some((self, NextIfEqFn { expected, _next: PhantomData })) }, + } + } +} + +impl<St: Stream> FusedStream for Peekable<St> { + fn is_terminated(&self) -> bool { + self.peeked.is_none() && self.stream.is_terminated() + } +} + +impl<S: Stream> Stream for Peekable<S> { + type Item = S::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let this = self.project(); + if let Some(item) = this.peeked.take() { + return Poll::Ready(Some(item)); + } + this.stream.poll_next(cx) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let peek_len = usize::from(self.peeked.is_some()); + let (lower, upper) = self.stream.size_hint(); + let lower = lower.saturating_add(peek_len); + let upper = match upper { + Some(x) => x.checked_add(peek_len), + None => None, + }; + (lower, upper) + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for Peekable<S> +where + S: Sink<Item> + Stream, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} + +pin_project! { + /// Future for the [`Peekable::peek`](self::Peekable::peek) method. + #[must_use = "futures do nothing unless polled"] + pub struct Peek<'a, St: Stream> { + inner: Option<Pin<&'a mut Peekable<St>>>, + } +} + +impl<St> fmt::Debug for Peek<'_, St> +where + St: Stream + fmt::Debug, + St::Item: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Peek").field("inner", &self.inner).finish() + } +} + +impl<St: Stream> FusedFuture for Peek<'_, St> { + fn is_terminated(&self) -> bool { + self.inner.is_none() + } +} + +impl<'a, St> Future for Peek<'a, St> +where + St: Stream, +{ + type Output = Option<&'a St::Item>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let inner = self.project().inner; + if let Some(peekable) = inner { + ready!(peekable.as_mut().poll_peek(cx)); + + inner.take().unwrap().poll_peek(cx) + } else { + panic!("Peek polled after completion") + } + } +} + +pin_project! { + /// Future for the [`Peekable::peek_mut`](self::Peekable::peek_mut) method. + #[must_use = "futures do nothing unless polled"] + pub struct PeekMut<'a, St: Stream> { + inner: Option<Pin<&'a mut Peekable<St>>>, + } +} + +impl<St> fmt::Debug for PeekMut<'_, St> +where + St: Stream + fmt::Debug, + St::Item: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("PeekMut").field("inner", &self.inner).finish() + } +} + +impl<St: Stream> FusedFuture for PeekMut<'_, St> { + fn is_terminated(&self) -> bool { + self.inner.is_none() + } +} + +impl<'a, St> Future for PeekMut<'a, St> +where + St: Stream, +{ + type Output = Option<&'a mut St::Item>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let inner = self.project().inner; + if let Some(peekable) = inner { + ready!(peekable.as_mut().poll_peek_mut(cx)); + + inner.take().unwrap().poll_peek_mut(cx) + } else { + panic!("PeekMut polled after completion") + } + } +} + +pin_project! { + /// Future for the [`Peekable::next_if`](self::Peekable::next_if) method. + #[must_use = "futures do nothing unless polled"] + pub struct NextIf<'a, St: Stream, F> { + inner: Option<(Pin<&'a mut Peekable<St>>, F)>, + } +} + +impl<St, F> fmt::Debug for NextIf<'_, St, F> +where + St: Stream + fmt::Debug, + St::Item: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("NextIf").field("inner", &self.inner.as_ref().map(|(s, _f)| s)).finish() + } +} + +#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 +impl<St, F> FusedFuture for NextIf<'_, St, F> +where + St: Stream, + F: for<'a> FnOnce1<&'a St::Item, Output = bool>, +{ + fn is_terminated(&self) -> bool { + self.inner.is_none() + } +} + +#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 +impl<St, F> Future for NextIf<'_, St, F> +where + St: Stream, + F: for<'a> FnOnce1<&'a St::Item, Output = bool>, +{ + type Output = Option<St::Item>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let inner = self.project().inner; + if let Some((peekable, _)) = inner { + let res = ready!(peekable.as_mut().poll_next(cx)); + + let (peekable, func) = inner.take().unwrap(); + match res { + Some(ref matched) if func.call_once(matched) => Poll::Ready(res), + other => { + let peekable = peekable.project(); + // Since we called `self.next()`, we consumed `self.peeked`. + assert!(peekable.peeked.is_none()); + *peekable.peeked = other; + Poll::Ready(None) + } + } + } else { + panic!("NextIf polled after completion") + } + } +} + +pin_project! { + /// Future for the [`Peekable::next_if_eq`](self::Peekable::next_if_eq) method. + #[must_use = "futures do nothing unless polled"] + pub struct NextIfEq<'a, St: Stream, T: ?Sized> { + #[pin] + inner: NextIf<'a, St, NextIfEqFn<'a, T, St::Item>>, + } +} + +impl<St, T> fmt::Debug for NextIfEq<'_, St, T> +where + St: Stream + fmt::Debug, + St::Item: fmt::Debug, + T: ?Sized, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("NextIfEq") + .field("inner", &self.inner.inner.as_ref().map(|(s, _f)| s)) + .finish() + } +} + +impl<St, T> FusedFuture for NextIfEq<'_, St, T> +where + St: Stream, + T: ?Sized, + St::Item: PartialEq<T>, +{ + fn is_terminated(&self) -> bool { + self.inner.is_terminated() + } +} + +impl<St, T> Future for NextIfEq<'_, St, T> +where + St: Stream, + T: ?Sized, + St::Item: PartialEq<T>, +{ + type Output = Option<St::Item>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + self.project().inner.poll(cx) + } +} + +struct NextIfEqFn<'a, T: ?Sized, Item> { + expected: &'a T, + _next: PhantomData<Item>, +} + +impl<T, Item> FnOnce1<&Item> for NextIfEqFn<'_, T, Item> +where + T: ?Sized, + Item: PartialEq<T>, +{ + type Output = bool; + + fn call_once(self, next: &Item) -> Self::Output { + next == self.expected + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/ready_chunks.rs b/third_party/rust/futures-util/src/stream/stream/ready_chunks.rs new file mode 100644 index 0000000000..192054c4ae --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/ready_chunks.rs @@ -0,0 +1,93 @@ +use crate::stream::{Fuse, StreamExt}; +use alloc::vec::Vec; +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`ready_chunks`](super::StreamExt::ready_chunks) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct ReadyChunks<St: Stream> { + #[pin] + stream: Fuse<St>, + cap: usize, // https://github.com/rust-lang/futures-rs/issues/1475 + } +} + +impl<St: Stream> ReadyChunks<St> { + pub(super) fn new(stream: St, capacity: usize) -> Self { + assert!(capacity > 0); + + Self { stream: stream.fuse(), cap: capacity } + } + + delegate_access_inner!(stream, St, (.)); +} + +impl<St: Stream> Stream for ReadyChunks<St> { + type Item = Vec<St::Item>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + let mut items: Vec<St::Item> = Vec::new(); + + loop { + match this.stream.as_mut().poll_next(cx) { + // Flush all collected data if underlying stream doesn't contain + // more ready values + Poll::Pending => { + return if items.is_empty() { Poll::Pending } else { Poll::Ready(Some(items)) } + } + + // Push the ready item into the buffer and check whether it is full. + // If so, replace our buffer with a new and empty one and return + // the full one. + Poll::Ready(Some(item)) => { + if items.is_empty() { + items.reserve(*this.cap); + } + items.push(item); + if items.len() >= *this.cap { + return Poll::Ready(Some(items)); + } + } + + // Since the underlying stream ran out of values, return what we + // have buffered, if we have anything. + Poll::Ready(None) => { + let last = if items.is_empty() { None } else { Some(items) }; + + return Poll::Ready(last); + } + } + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let (lower, upper) = self.stream.size_hint(); + let lower = lower / self.cap; + (lower, upper) + } +} + +impl<St: Stream> FusedStream for ReadyChunks<St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for ReadyChunks<S> +where + S: Stream + Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/scan.rs b/third_party/rust/futures-util/src/stream/stream/scan.rs new file mode 100644 index 0000000000..f5cfde9c36 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/scan.rs @@ -0,0 +1,128 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +struct StateFn<S, F> { + state: S, + f: F, +} + +pin_project! { + /// Stream for the [`scan`](super::StreamExt::scan) method. + #[must_use = "streams do nothing unless polled"] + pub struct Scan<St: Stream, S, Fut, F> { + #[pin] + stream: St, + state_f: Option<StateFn<S, F>>, + #[pin] + future: Option<Fut>, + } +} + +impl<St, S, Fut, F> fmt::Debug for Scan<St, S, Fut, F> +where + St: Stream + fmt::Debug, + St::Item: fmt::Debug, + S: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Scan") + .field("stream", &self.stream) + .field("state", &self.state_f.as_ref().map(|s| &s.state)) + .field("future", &self.future) + .field("done_taking", &self.is_done_taking()) + .finish() + } +} + +impl<St: Stream, S, Fut, F> Scan<St, S, Fut, F> { + /// Checks if internal state is `None`. + fn is_done_taking(&self) -> bool { + self.state_f.is_none() + } +} + +impl<B, St, S, Fut, F> Scan<St, S, Fut, F> +where + St: Stream, + F: FnMut(&mut S, St::Item) -> Fut, + Fut: Future<Output = Option<B>>, +{ + pub(super) fn new(stream: St, initial_state: S, f: F) -> Self { + Self { stream, state_f: Some(StateFn { state: initial_state, f }), future: None } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<B, St, S, Fut, F> Stream for Scan<St, S, Fut, F> +where + St: Stream, + F: FnMut(&mut S, St::Item) -> Fut, + Fut: Future<Output = Option<B>>, +{ + type Item = B; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<B>> { + if self.is_done_taking() { + return Poll::Ready(None); + } + + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + let item = ready!(fut.poll(cx)); + this.future.set(None); + + if item.is_none() { + *this.state_f = None; + } + + break item; + } else if let Some(item) = ready!(this.stream.as_mut().poll_next(cx)) { + let state_f = this.state_f.as_mut().unwrap(); + this.future.set(Some((state_f.f)(&mut state_f.state, item))) + } else { + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.is_done_taking() { + (0, Some(0)) + } else { + self.stream.size_hint() // can't know a lower bound, due to the predicate + } + } +} + +impl<B, St, S, Fut, F> FusedStream for Scan<St, S, Fut, F> +where + St: FusedStream, + F: FnMut(&mut S, St::Item) -> Fut, + Fut: Future<Output = Option<B>>, +{ + fn is_terminated(&self) -> bool { + self.is_done_taking() || self.future.is_none() && self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<St, S, Fut, F, Item> Sink<Item> for Scan<St, S, Fut, F> +where + St: Stream + Sink<Item>, +{ + type Error = St::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/select_next_some.rs b/third_party/rust/futures-util/src/stream/stream/select_next_some.rs new file mode 100644 index 0000000000..3115e14d9a --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/select_next_some.rs @@ -0,0 +1,42 @@ +use crate::stream::StreamExt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::FusedStream; +use futures_core::task::{Context, Poll}; + +/// Future for the [`select_next_some`](super::StreamExt::select_next_some) +/// method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct SelectNextSome<'a, St: ?Sized> { + stream: &'a mut St, +} + +impl<'a, St: ?Sized> SelectNextSome<'a, St> { + pub(super) fn new(stream: &'a mut St) -> Self { + Self { stream } + } +} + +impl<St: ?Sized + FusedStream + Unpin> FusedFuture for SelectNextSome<'_, St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St: ?Sized + FusedStream + Unpin> Future for SelectNextSome<'_, St> { + type Output = St::Item; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + assert!(!self.stream.is_terminated(), "SelectNextSome polled after terminated"); + + if let Some(item) = ready!(self.stream.poll_next_unpin(cx)) { + Poll::Ready(item) + } else { + debug_assert!(self.stream.is_terminated()); + cx.waker().wake_by_ref(); + Poll::Pending + } + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/skip.rs b/third_party/rust/futures-util/src/stream/stream/skip.rs new file mode 100644 index 0000000000..f495779521 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/skip.rs @@ -0,0 +1,70 @@ +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`skip`](super::StreamExt::skip) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Skip<St> { + #[pin] + stream: St, + remaining: usize, + } +} + +impl<St: Stream> Skip<St> { + pub(super) fn new(stream: St, n: usize) -> Self { + Self { stream, remaining: n } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St: FusedStream> FusedStream for Skip<St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St: Stream> Stream for Skip<St> { + type Item = St::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<St::Item>> { + let mut this = self.project(); + + while *this.remaining > 0 { + if ready!(this.stream.as_mut().poll_next(cx)).is_some() { + *this.remaining -= 1; + } else { + return Poll::Ready(None); + } + } + + this.stream.poll_next(cx) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let (lower, upper) = self.stream.size_hint(); + + let lower = lower.saturating_sub(self.remaining); + let upper = upper.map(|x| x.saturating_sub(self.remaining)); + + (lower, upper) + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for Skip<S> +where + S: Stream + Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/skip_while.rs b/third_party/rust/futures-util/src/stream/stream/skip_while.rs new file mode 100644 index 0000000000..dabd5eefae --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/skip_while.rs @@ -0,0 +1,124 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`skip_while`](super::StreamExt::skip_while) method. + #[must_use = "streams do nothing unless polled"] + pub struct SkipWhile<St, Fut, F> where St: Stream { + #[pin] + stream: St, + f: F, + #[pin] + pending_fut: Option<Fut>, + pending_item: Option<St::Item>, + done_skipping: bool, + } +} + +impl<St, Fut, F> fmt::Debug for SkipWhile<St, Fut, F> +where + St: Stream + fmt::Debug, + St::Item: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("SkipWhile") + .field("stream", &self.stream) + .field("pending_fut", &self.pending_fut) + .field("pending_item", &self.pending_item) + .field("done_skipping", &self.done_skipping) + .finish() + } +} + +impl<St, Fut, F> SkipWhile<St, Fut, F> +where + St: Stream, + F: FnMut(&St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, pending_fut: None, pending_item: None, done_skipping: false } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> FusedStream for SkipWhile<St, Fut, F> +where + St: FusedStream, + F: FnMut(&St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + fn is_terminated(&self) -> bool { + self.pending_item.is_none() && self.stream.is_terminated() + } +} + +impl<St, Fut, F> Stream for SkipWhile<St, Fut, F> +where + St: Stream, + F: FnMut(&St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + type Item = St::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<St::Item>> { + let mut this = self.project(); + + if *this.done_skipping { + return this.stream.poll_next(cx); + } + + Poll::Ready(loop { + if let Some(fut) = this.pending_fut.as_mut().as_pin_mut() { + let skipped = ready!(fut.poll(cx)); + let item = this.pending_item.take(); + this.pending_fut.set(None); + if !skipped { + *this.done_skipping = true; + break item; + } + } else if let Some(item) = ready!(this.stream.as_mut().poll_next(cx)) { + this.pending_fut.set(Some((this.f)(&item))); + *this.pending_item = Some(item); + } else { + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.done_skipping { + self.stream.size_hint() + } else { + let pending_len = usize::from(self.pending_item.is_some()); + let (_, upper) = self.stream.size_hint(); + let upper = match upper { + Some(x) => x.checked_add(pending_len), + None => None, + }; + (0, upper) // can't know a lower bound, due to the predicate + } + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item> Sink<Item> for SkipWhile<S, Fut, F> +where + S: Stream + Sink<Item>, + F: FnMut(&S::Item) -> Fut, + Fut: Future<Output = bool>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/split.rs b/third_party/rust/futures-util/src/stream/stream/split.rs new file mode 100644 index 0000000000..e2034e0c27 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/split.rs @@ -0,0 +1,144 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +use futures_sink::Sink; + +use crate::lock::BiLock; + +/// A `Stream` part of the split pair +#[derive(Debug)] +#[must_use = "streams do nothing unless polled"] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub struct SplitStream<S>(BiLock<S>); + +impl<S> Unpin for SplitStream<S> {} + +impl<S: Unpin> SplitStream<S> { + /// Attempts to put the two "halves" of a split `Stream + Sink` back + /// together. Succeeds only if the `SplitStream<S>` and `SplitSink<S>` are + /// a matching pair originating from the same call to `StreamExt::split`. + pub fn reunite<Item>(self, other: SplitSink<S, Item>) -> Result<S, ReuniteError<S, Item>> + where + S: Sink<Item>, + { + other.reunite(self) + } +} + +impl<S: Stream> Stream for SplitStream<S> { + type Item = S::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<S::Item>> { + ready!(self.0.poll_lock(cx)).as_pin_mut().poll_next(cx) + } +} + +#[allow(non_snake_case)] +fn SplitSink<S: Sink<Item>, Item>(lock: BiLock<S>) -> SplitSink<S, Item> { + SplitSink { lock, slot: None } +} + +/// A `Sink` part of the split pair +#[derive(Debug)] +#[must_use = "sinks do nothing unless polled"] +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub struct SplitSink<S, Item> { + lock: BiLock<S>, + slot: Option<Item>, +} + +impl<S, Item> Unpin for SplitSink<S, Item> {} + +impl<S: Sink<Item> + Unpin, Item> SplitSink<S, Item> { + /// Attempts to put the two "halves" of a split `Stream + Sink` back + /// together. Succeeds only if the `SplitStream<S>` and `SplitSink<S>` are + /// a matching pair originating from the same call to `StreamExt::split`. + pub fn reunite(self, other: SplitStream<S>) -> Result<S, ReuniteError<S, Item>> { + self.lock.reunite(other.0).map_err(|err| ReuniteError(SplitSink(err.0), SplitStream(err.1))) + } +} + +impl<S: Sink<Item>, Item> SplitSink<S, Item> { + fn poll_flush_slot( + mut inner: Pin<&mut S>, + slot: &mut Option<Item>, + cx: &mut Context<'_>, + ) -> Poll<Result<(), S::Error>> { + if slot.is_some() { + ready!(inner.as_mut().poll_ready(cx))?; + Poll::Ready(inner.start_send(slot.take().unwrap())) + } else { + Poll::Ready(Ok(())) + } + } + + fn poll_lock_and_flush_slot( + mut self: Pin<&mut Self>, + cx: &mut Context<'_>, + ) -> Poll<Result<(), S::Error>> { + let this = &mut *self; + let mut inner = ready!(this.lock.poll_lock(cx)); + Self::poll_flush_slot(inner.as_pin_mut(), &mut this.slot, cx) + } +} + +impl<S: Sink<Item>, Item> Sink<Item> for SplitSink<S, Item> { + type Error = S::Error; + + fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::Error>> { + loop { + if self.slot.is_none() { + return Poll::Ready(Ok(())); + } + ready!(self.as_mut().poll_lock_and_flush_slot(cx))?; + } + } + + fn start_send(mut self: Pin<&mut Self>, item: Item) -> Result<(), S::Error> { + self.slot = Some(item); + Ok(()) + } + + fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::Error>> { + let this = &mut *self; + let mut inner = ready!(this.lock.poll_lock(cx)); + ready!(Self::poll_flush_slot(inner.as_pin_mut(), &mut this.slot, cx))?; + inner.as_pin_mut().poll_flush(cx) + } + + fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::Error>> { + let this = &mut *self; + let mut inner = ready!(this.lock.poll_lock(cx)); + ready!(Self::poll_flush_slot(inner.as_pin_mut(), &mut this.slot, cx))?; + inner.as_pin_mut().poll_close(cx) + } +} + +pub(super) fn split<S: Stream + Sink<Item>, Item>(s: S) -> (SplitSink<S, Item>, SplitStream<S>) { + let (a, b) = BiLock::new(s); + let read = SplitStream(a); + let write = SplitSink(b); + (write, read) +} + +/// Error indicating a `SplitSink<S>` and `SplitStream<S>` were not two halves +/// of a `Stream + Split`, and thus could not be `reunite`d. +#[cfg_attr(docsrs, doc(cfg(feature = "sink")))] +pub struct ReuniteError<T, Item>(pub SplitSink<T, Item>, pub SplitStream<T>); + +impl<T, Item> fmt::Debug for ReuniteError<T, Item> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple("ReuniteError").field(&"...").finish() + } +} + +impl<T, Item> fmt::Display for ReuniteError<T, Item> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "tried to reunite a SplitStream and SplitSink that don't form a pair") + } +} + +#[cfg(feature = "std")] +impl<T: core::any::Any, Item> std::error::Error for ReuniteError<T, Item> {} diff --git a/third_party/rust/futures-util/src/stream/stream/take.rs b/third_party/rust/futures-util/src/stream/stream/take.rs new file mode 100644 index 0000000000..29d6c39ee3 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/take.rs @@ -0,0 +1,86 @@ +use core::cmp; +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`take`](super::StreamExt::take) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Take<St> { + #[pin] + stream: St, + remaining: usize, + } +} + +impl<St: Stream> Take<St> { + pub(super) fn new(stream: St, n: usize) -> Self { + Self { stream, remaining: n } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St> Stream for Take<St> +where + St: Stream, +{ + type Item = St::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<St::Item>> { + if self.remaining == 0 { + Poll::Ready(None) + } else { + let this = self.project(); + let next = ready!(this.stream.poll_next(cx)); + if next.is_some() { + *this.remaining -= 1; + } else { + *this.remaining = 0; + } + Poll::Ready(next) + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.remaining == 0 { + return (0, Some(0)); + } + + let (lower, upper) = self.stream.size_hint(); + + let lower = cmp::min(lower, self.remaining); + + let upper = match upper { + Some(x) if x < self.remaining => Some(x), + _ => Some(self.remaining), + }; + + (lower, upper) + } +} + +impl<St> FusedStream for Take<St> +where + St: FusedStream, +{ + fn is_terminated(&self) -> bool { + self.remaining == 0 || self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for Take<S> +where + S: Stream + Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/take_until.rs b/third_party/rust/futures-util/src/stream/stream/take_until.rs new file mode 100644 index 0000000000..d14f9ce100 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/take_until.rs @@ -0,0 +1,170 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +// FIXME: docs, tests + +pin_project! { + /// Stream for the [`take_until`](super::StreamExt::take_until) method. + #[must_use = "streams do nothing unless polled"] + pub struct TakeUntil<St: Stream, Fut: Future> { + #[pin] + stream: St, + // Contains the inner Future on start and None once the inner Future is resolved + // or taken out by the user. + #[pin] + fut: Option<Fut>, + // Contains fut's return value once fut is resolved + fut_result: Option<Fut::Output>, + // Whether the future was taken out by the user. + free: bool, + } +} + +impl<St, Fut> fmt::Debug for TakeUntil<St, Fut> +where + St: Stream + fmt::Debug, + St::Item: fmt::Debug, + Fut: Future + fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TakeUntil").field("stream", &self.stream).field("fut", &self.fut).finish() + } +} + +impl<St, Fut> TakeUntil<St, Fut> +where + St: Stream, + Fut: Future, +{ + pub(super) fn new(stream: St, fut: Fut) -> Self { + Self { stream, fut: Some(fut), fut_result: None, free: false } + } + + delegate_access_inner!(stream, St, ()); + + /// Extract the stopping future out of the combinator. + /// The future is returned only if it isn't resolved yet, ie. if the stream isn't stopped yet. + /// Taking out the future means the combinator will be yielding + /// elements from the wrapped stream without ever stopping it. + pub fn take_future(&mut self) -> Option<Fut> { + if self.fut.is_some() { + self.free = true; + } + + self.fut.take() + } + + /// Once the stopping future is resolved, this method can be used + /// to extract the value returned by the stopping future. + /// + /// This may be used to retrieve arbitrary data from the stopping + /// future, for example a reason why the stream was stopped. + /// + /// This method will return `None` if the future isn't resolved yet, + /// or if the result was already taken out. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt}; + /// use futures::task::Poll; + /// + /// let stream = stream::iter(1..=10); + /// + /// let mut i = 0; + /// let stop_fut = future::poll_fn(|_cx| { + /// i += 1; + /// if i <= 5 { + /// Poll::Pending + /// } else { + /// Poll::Ready("reason") + /// } + /// }); + /// + /// let mut stream = stream.take_until(stop_fut); + /// let _ = stream.by_ref().collect::<Vec<_>>().await; + /// + /// let result = stream.take_result().unwrap(); + /// assert_eq!(result, "reason"); + /// # }); + /// ``` + pub fn take_result(&mut self) -> Option<Fut::Output> { + self.fut_result.take() + } + + /// Whether the stream was stopped yet by the stopping future + /// being resolved. + pub fn is_stopped(&self) -> bool { + !self.free && self.fut.is_none() + } +} + +impl<St, Fut> Stream for TakeUntil<St, Fut> +where + St: Stream, + Fut: Future, +{ + type Item = St::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<St::Item>> { + let mut this = self.project(); + + if let Some(f) = this.fut.as_mut().as_pin_mut() { + if let Poll::Ready(result) = f.poll(cx) { + this.fut.set(None); + *this.fut_result = Some(result); + } + } + + if !*this.free && this.fut.is_none() { + // Future resolved, inner stream stopped + Poll::Ready(None) + } else { + // Future either not resolved yet or taken out by the user + let item = ready!(this.stream.poll_next(cx)); + if item.is_none() { + this.fut.set(None); + } + Poll::Ready(item) + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.is_stopped() { + return (0, Some(0)); + } + + self.stream.size_hint() + } +} + +impl<St, Fut> FusedStream for TakeUntil<St, Fut> +where + St: Stream, + Fut: Future, +{ + fn is_terminated(&self) -> bool { + self.is_stopped() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, Item> Sink<Item> for TakeUntil<S, Fut> +where + S: Stream + Sink<Item>, + Fut: Future, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/take_while.rs b/third_party/rust/futures-util/src/stream/stream/take_while.rs new file mode 100644 index 0000000000..9256943010 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/take_while.rs @@ -0,0 +1,124 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`take_while`](super::StreamExt::take_while) method. + #[must_use = "streams do nothing unless polled"] + pub struct TakeWhile<St: Stream, Fut, F> { + #[pin] + stream: St, + f: F, + #[pin] + pending_fut: Option<Fut>, + pending_item: Option<St::Item>, + done_taking: bool, + } +} + +impl<St, Fut, F> fmt::Debug for TakeWhile<St, Fut, F> +where + St: Stream + fmt::Debug, + St::Item: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TakeWhile") + .field("stream", &self.stream) + .field("pending_fut", &self.pending_fut) + .field("pending_item", &self.pending_item) + .field("done_taking", &self.done_taking) + .finish() + } +} + +impl<St, Fut, F> TakeWhile<St, Fut, F> +where + St: Stream, + F: FnMut(&St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, pending_fut: None, pending_item: None, done_taking: false } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> Stream for TakeWhile<St, Fut, F> +where + St: Stream, + F: FnMut(&St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + type Item = St::Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<St::Item>> { + if self.done_taking { + return Poll::Ready(None); + } + + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(fut) = this.pending_fut.as_mut().as_pin_mut() { + let take = ready!(fut.poll(cx)); + let item = this.pending_item.take(); + this.pending_fut.set(None); + if take { + break item; + } else { + *this.done_taking = true; + break None; + } + } else if let Some(item) = ready!(this.stream.as_mut().poll_next(cx)) { + this.pending_fut.set(Some((this.f)(&item))); + *this.pending_item = Some(item); + } else { + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.done_taking { + return (0, Some(0)); + } + + let pending_len = usize::from(self.pending_item.is_some()); + let (_, upper) = self.stream.size_hint(); + let upper = match upper { + Some(x) => x.checked_add(pending_len), + None => None, + }; + (0, upper) // can't know a lower bound, due to the predicate + } +} + +impl<St, Fut, F> FusedStream for TakeWhile<St, Fut, F> +where + St: FusedStream, + F: FnMut(&St::Item) -> Fut, + Fut: Future<Output = bool>, +{ + fn is_terminated(&self) -> bool { + self.done_taking || self.pending_item.is_none() && self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item> Sink<Item> for TakeWhile<S, Fut, F> +where + S: Stream + Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/then.rs b/third_party/rust/futures-util/src/stream/stream/then.rs new file mode 100644 index 0000000000..9192c0b0cf --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/then.rs @@ -0,0 +1,101 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`then`](super::StreamExt::then) method. + #[must_use = "streams do nothing unless polled"] + pub struct Then<St, Fut, F> { + #[pin] + stream: St, + #[pin] + future: Option<Fut>, + f: F, + } +} + +impl<St, Fut, F> fmt::Debug for Then<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Then").field("stream", &self.stream).field("future", &self.future).finish() + } +} + +impl<St, Fut, F> Then<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, future: None, f } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> FusedStream for Then<St, Fut, F> +where + St: FusedStream, + F: FnMut(St::Item) -> Fut, + Fut: Future, +{ + fn is_terminated(&self) -> bool { + self.future.is_none() && self.stream.is_terminated() + } +} + +impl<St, Fut, F> Stream for Then<St, Fut, F> +where + St: Stream, + F: FnMut(St::Item) -> Fut, + Fut: Future, +{ + type Item = Fut::Output; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + let item = ready!(fut.poll(cx)); + this.future.set(None); + break Some(item); + } else if let Some(item) = ready!(this.stream.as_mut().poll_next(cx)) { + this.future.set(Some((this.f)(item))); + } else { + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let future_len = usize::from(self.future.is_some()); + let (lower, upper) = self.stream.size_hint(); + let lower = lower.saturating_add(future_len); + let upper = match upper { + Some(x) => x.checked_add(future_len), + None => None, + }; + (lower, upper) + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item> Sink<Item> for Then<S, Fut, F> +where + S: Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/stream/unzip.rs b/third_party/rust/futures-util/src/stream/stream/unzip.rs new file mode 100644 index 0000000000..a88cf03266 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/unzip.rs @@ -0,0 +1,63 @@ +use core::mem; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`unzip`](super::StreamExt::unzip) method. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Unzip<St, FromA, FromB> { + #[pin] + stream: St, + left: FromA, + right: FromB, + } +} + +impl<St: Stream, FromA: Default, FromB: Default> Unzip<St, FromA, FromB> { + fn finish(self: Pin<&mut Self>) -> (FromA, FromB) { + let this = self.project(); + (mem::take(this.left), mem::take(this.right)) + } + + pub(super) fn new(stream: St) -> Self { + Self { stream, left: Default::default(), right: Default::default() } + } +} + +impl<St, A, B, FromA, FromB> FusedFuture for Unzip<St, FromA, FromB> +where + St: FusedStream<Item = (A, B)>, + FromA: Default + Extend<A>, + FromB: Default + Extend<B>, +{ + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St, A, B, FromA, FromB> Future for Unzip<St, FromA, FromB> +where + St: Stream<Item = (A, B)>, + FromA: Default + Extend<A>, + FromB: Default + Extend<B>, +{ + type Output = (FromA, FromB); + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<(FromA, FromB)> { + let mut this = self.as_mut().project(); + loop { + match ready!(this.stream.as_mut().poll_next(cx)) { + Some(e) => { + this.left.extend(Some(e.0)); + this.right.extend(Some(e.1)); + } + None => return Poll::Ready(self.finish()), + } + } + } +} diff --git a/third_party/rust/futures-util/src/stream/stream/zip.rs b/third_party/rust/futures-util/src/stream/stream/zip.rs new file mode 100644 index 0000000000..25a47e96be --- /dev/null +++ b/third_party/rust/futures-util/src/stream/stream/zip.rs @@ -0,0 +1,128 @@ +use crate::stream::{Fuse, StreamExt}; +use core::cmp; +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`zip`](super::StreamExt::zip) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct Zip<St1: Stream, St2: Stream> { + #[pin] + stream1: Fuse<St1>, + #[pin] + stream2: Fuse<St2>, + queued1: Option<St1::Item>, + queued2: Option<St2::Item>, + } +} + +impl<St1: Stream, St2: Stream> Zip<St1, St2> { + pub(super) fn new(stream1: St1, stream2: St2) -> Self { + Self { stream1: stream1.fuse(), stream2: stream2.fuse(), queued1: None, queued2: None } + } + + /// Acquires a reference to the underlying streams that this combinator is + /// pulling from. + pub fn get_ref(&self) -> (&St1, &St2) { + (self.stream1.get_ref(), self.stream2.get_ref()) + } + + /// Acquires a mutable reference to the underlying streams that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// stream which may otherwise confuse this combinator. + pub fn get_mut(&mut self) -> (&mut St1, &mut St2) { + (self.stream1.get_mut(), self.stream2.get_mut()) + } + + /// Acquires a pinned mutable reference to the underlying streams that this + /// combinator is pulling from. + /// + /// Note that care must be taken to avoid tampering with the state of the + /// stream which may otherwise confuse this combinator. + pub fn get_pin_mut(self: Pin<&mut Self>) -> (Pin<&mut St1>, Pin<&mut St2>) { + let this = self.project(); + (this.stream1.get_pin_mut(), this.stream2.get_pin_mut()) + } + + /// Consumes this combinator, returning the underlying streams. + /// + /// Note that this may discard intermediate state of this combinator, so + /// care should be taken to avoid losing resources when this is called. + pub fn into_inner(self) -> (St1, St2) { + (self.stream1.into_inner(), self.stream2.into_inner()) + } +} + +impl<St1, St2> FusedStream for Zip<St1, St2> +where + St1: Stream, + St2: Stream, +{ + fn is_terminated(&self) -> bool { + self.stream1.is_terminated() && self.stream2.is_terminated() + } +} + +impl<St1, St2> Stream for Zip<St1, St2> +where + St1: Stream, + St2: Stream, +{ + type Item = (St1::Item, St2::Item); + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + if this.queued1.is_none() { + match this.stream1.as_mut().poll_next(cx) { + Poll::Ready(Some(item1)) => *this.queued1 = Some(item1), + Poll::Ready(None) | Poll::Pending => {} + } + } + if this.queued2.is_none() { + match this.stream2.as_mut().poll_next(cx) { + Poll::Ready(Some(item2)) => *this.queued2 = Some(item2), + Poll::Ready(None) | Poll::Pending => {} + } + } + + if this.queued1.is_some() && this.queued2.is_some() { + let pair = (this.queued1.take().unwrap(), this.queued2.take().unwrap()); + Poll::Ready(Some(pair)) + } else if this.stream1.is_done() || this.stream2.is_done() { + Poll::Ready(None) + } else { + Poll::Pending + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let queued1_len = usize::from(self.queued1.is_some()); + let queued2_len = usize::from(self.queued2.is_some()); + let (stream1_lower, stream1_upper) = self.stream1.size_hint(); + let (stream2_lower, stream2_upper) = self.stream2.size_hint(); + + let stream1_lower = stream1_lower.saturating_add(queued1_len); + let stream2_lower = stream2_lower.saturating_add(queued2_len); + + let lower = cmp::min(stream1_lower, stream2_lower); + + let upper = match (stream1_upper, stream2_upper) { + (Some(x), Some(y)) => { + let x = x.saturating_add(queued1_len); + let y = y.saturating_add(queued2_len); + Some(cmp::min(x, y)) + } + (Some(x), None) => x.checked_add(queued1_len), + (None, Some(y)) => y.checked_add(queued2_len), + (None, None) => None, + }; + + (lower, upper) + } +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/and_then.rs b/third_party/rust/futures-util/src/stream/try_stream/and_then.rs new file mode 100644 index 0000000000..2f8b6f2589 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/and_then.rs @@ -0,0 +1,105 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::TryFuture; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`and_then`](super::TryStreamExt::and_then) method. + #[must_use = "streams do nothing unless polled"] + pub struct AndThen<St, Fut, F> { + #[pin] + stream: St, + #[pin] + future: Option<Fut>, + f: F, + } +} + +impl<St, Fut, F> fmt::Debug for AndThen<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("AndThen") + .field("stream", &self.stream) + .field("future", &self.future) + .finish() + } +} + +impl<St, Fut, F> AndThen<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Ok) -> Fut, + Fut: TryFuture<Error = St::Error>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, future: None, f } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> Stream for AndThen<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Ok) -> Fut, + Fut: TryFuture<Error = St::Error>, +{ + type Item = Result<Fut::Ok, St::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + let item = ready!(fut.try_poll(cx)); + this.future.set(None); + break Some(item); + } else if let Some(item) = ready!(this.stream.as_mut().try_poll_next(cx)?) { + this.future.set(Some((this.f)(item))); + } else { + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let future_len = usize::from(self.future.is_some()); + let (lower, upper) = self.stream.size_hint(); + let lower = lower.saturating_add(future_len); + let upper = match upper { + Some(x) => x.checked_add(future_len), + None => None, + }; + (lower, upper) + } +} + +impl<St, Fut, F> FusedStream for AndThen<St, Fut, F> +where + St: TryStream + FusedStream, + F: FnMut(St::Ok) -> Fut, + Fut: TryFuture<Error = St::Error>, +{ + fn is_terminated(&self) -> bool { + self.future.is_none() && self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item> Sink<Item> for AndThen<S, Fut, F> +where + S: Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/into_async_read.rs b/third_party/rust/futures-util/src/stream/try_stream/into_async_read.rs new file mode 100644 index 0000000000..ffbfc7eae9 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/into_async_read.rs @@ -0,0 +1,166 @@ +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::TryStream; +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncBufRead, AsyncRead, AsyncWrite}; +use pin_project_lite::pin_project; +use std::cmp; +use std::io::{Error, Result}; + +pin_project! { + /// Reader for the [`into_async_read`](super::TryStreamExt::into_async_read) method. + #[derive(Debug)] + #[must_use = "readers do nothing unless polled"] + #[cfg_attr(docsrs, doc(cfg(feature = "io")))] + pub struct IntoAsyncRead<St> + where + St: TryStream<Error = Error>, + St::Ok: AsRef<[u8]>, + { + #[pin] + stream: St, + state: ReadState<St::Ok>, + } +} + +#[derive(Debug)] +enum ReadState<T: AsRef<[u8]>> { + Ready { chunk: T, chunk_start: usize }, + PendingChunk, + Eof, +} + +impl<St> IntoAsyncRead<St> +where + St: TryStream<Error = Error>, + St::Ok: AsRef<[u8]>, +{ + pub(super) fn new(stream: St) -> Self { + Self { stream, state: ReadState::PendingChunk } + } +} + +impl<St> AsyncRead for IntoAsyncRead<St> +where + St: TryStream<Error = Error>, + St::Ok: AsRef<[u8]>, +{ + fn poll_read( + self: Pin<&mut Self>, + cx: &mut Context<'_>, + buf: &mut [u8], + ) -> Poll<Result<usize>> { + let mut this = self.project(); + + loop { + match this.state { + ReadState::Ready { chunk, chunk_start } => { + let chunk = chunk.as_ref(); + let len = cmp::min(buf.len(), chunk.len() - *chunk_start); + + buf[..len].copy_from_slice(&chunk[*chunk_start..*chunk_start + len]); + *chunk_start += len; + + if chunk.len() == *chunk_start { + *this.state = ReadState::PendingChunk; + } + + return Poll::Ready(Ok(len)); + } + ReadState::PendingChunk => match ready!(this.stream.as_mut().try_poll_next(cx)) { + Some(Ok(chunk)) => { + if !chunk.as_ref().is_empty() { + *this.state = ReadState::Ready { chunk, chunk_start: 0 }; + } + } + Some(Err(err)) => { + *this.state = ReadState::Eof; + return Poll::Ready(Err(err)); + } + None => { + *this.state = ReadState::Eof; + return Poll::Ready(Ok(0)); + } + }, + ReadState::Eof => { + return Poll::Ready(Ok(0)); + } + } + } + } +} + +impl<St> AsyncWrite for IntoAsyncRead<St> +where + St: TryStream<Error = Error> + AsyncWrite, + St::Ok: AsRef<[u8]>, +{ + fn poll_write(self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8]) -> Poll<Result<usize>> { + let this = self.project(); + this.stream.poll_write(cx, buf) + } + + fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> { + let this = self.project(); + this.stream.poll_flush(cx) + } + + fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> { + let this = self.project(); + this.stream.poll_close(cx) + } +} + +impl<St> AsyncBufRead for IntoAsyncRead<St> +where + St: TryStream<Error = Error>, + St::Ok: AsRef<[u8]>, +{ + fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<&[u8]>> { + let mut this = self.project(); + + while let ReadState::PendingChunk = this.state { + match ready!(this.stream.as_mut().try_poll_next(cx)) { + Some(Ok(chunk)) => { + if !chunk.as_ref().is_empty() { + *this.state = ReadState::Ready { chunk, chunk_start: 0 }; + } + } + Some(Err(err)) => { + *this.state = ReadState::Eof; + return Poll::Ready(Err(err)); + } + None => { + *this.state = ReadState::Eof; + return Poll::Ready(Ok(&[])); + } + } + } + + if let &mut ReadState::Ready { ref chunk, chunk_start } = this.state { + let chunk = chunk.as_ref(); + return Poll::Ready(Ok(&chunk[chunk_start..])); + } + + // To get to this point we must be in ReadState::Eof + Poll::Ready(Ok(&[])) + } + + fn consume(self: Pin<&mut Self>, amount: usize) { + let this = self.project(); + + // https://github.com/rust-lang/futures-rs/pull/1556#discussion_r281644295 + if amount == 0 { + return; + } + if let ReadState::Ready { chunk, chunk_start } = this.state { + *chunk_start += amount; + debug_assert!(*chunk_start <= chunk.as_ref().len()); + if *chunk_start >= chunk.as_ref().len() { + *this.state = ReadState::PendingChunk; + } + } else { + debug_assert!(false, "Attempted to consume from IntoAsyncRead without chunk"); + } + } +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/into_stream.rs b/third_party/rust/futures-util/src/stream/try_stream/into_stream.rs new file mode 100644 index 0000000000..2126258af7 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/into_stream.rs @@ -0,0 +1,52 @@ +use core::pin::Pin; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`into_stream`](super::TryStreamExt::into_stream) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct IntoStream<St> { + #[pin] + stream: St, + } +} + +impl<St> IntoStream<St> { + #[inline] + pub(super) fn new(stream: St) -> Self { + Self { stream } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St: TryStream + FusedStream> FusedStream for IntoStream<St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St: TryStream> Stream for IntoStream<St> { + type Item = Result<St::Ok, St::Error>; + + #[inline] + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + self.project().stream.try_poll_next(cx) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.stream.size_hint() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S: Sink<Item>, Item> Sink<Item> for IntoStream<S> { + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/mod.rs b/third_party/rust/futures-util/src/stream/try_stream/mod.rs new file mode 100644 index 0000000000..bc4c6e4f6a --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/mod.rs @@ -0,0 +1,1064 @@ +//! Streams +//! +//! This module contains a number of functions for working with `Streams`s +//! that return `Result`s, allowing for short-circuiting computations. + +#[cfg(feature = "compat")] +use crate::compat::Compat; +use crate::fns::{ + inspect_err_fn, inspect_ok_fn, into_fn, map_err_fn, map_ok_fn, InspectErrFn, InspectOkFn, + IntoFn, MapErrFn, MapOkFn, +}; +use crate::future::assert_future; +use crate::stream::assert_stream; +use crate::stream::{Inspect, Map}; +#[cfg(feature = "alloc")] +use alloc::vec::Vec; +use core::pin::Pin; +use futures_core::{ + future::{Future, TryFuture}, + stream::TryStream, + task::{Context, Poll}, +}; + +mod and_then; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::and_then::AndThen; + +delegate_all!( + /// Stream for the [`err_into`](super::TryStreamExt::err_into) method. + ErrInto<St, E>( + MapErr<St, IntoFn<E>> + ): Debug + Sink + Stream + FusedStream + AccessInner[St, (.)] + New[|x: St| MapErr::new(x, into_fn())] +); + +delegate_all!( + /// Stream for the [`inspect_ok`](super::TryStreamExt::inspect_ok) method. + InspectOk<St, F>( + Inspect<IntoStream<St>, InspectOkFn<F>> + ): Debug + Sink + Stream + FusedStream + AccessInner[St, (. .)] + New[|x: St, f: F| Inspect::new(IntoStream::new(x), inspect_ok_fn(f))] +); + +delegate_all!( + /// Stream for the [`inspect_err`](super::TryStreamExt::inspect_err) method. + InspectErr<St, F>( + Inspect<IntoStream<St>, InspectErrFn<F>> + ): Debug + Sink + Stream + FusedStream + AccessInner[St, (. .)] + New[|x: St, f: F| Inspect::new(IntoStream::new(x), inspect_err_fn(f))] +); + +mod into_stream; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::into_stream::IntoStream; + +delegate_all!( + /// Stream for the [`map_ok`](super::TryStreamExt::map_ok) method. + MapOk<St, F>( + Map<IntoStream<St>, MapOkFn<F>> + ): Debug + Sink + Stream + FusedStream + AccessInner[St, (. .)] + New[|x: St, f: F| Map::new(IntoStream::new(x), map_ok_fn(f))] +); + +delegate_all!( + /// Stream for the [`map_err`](super::TryStreamExt::map_err) method. + MapErr<St, F>( + Map<IntoStream<St>, MapErrFn<F>> + ): Debug + Sink + Stream + FusedStream + AccessInner[St, (. .)] + New[|x: St, f: F| Map::new(IntoStream::new(x), map_err_fn(f))] +); + +mod or_else; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::or_else::OrElse; + +mod try_next; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_next::TryNext; + +mod try_for_each; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_for_each::TryForEach; + +mod try_filter; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_filter::TryFilter; + +mod try_filter_map; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_filter_map::TryFilterMap; + +mod try_flatten; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_flatten::TryFlatten; + +mod try_collect; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_collect::TryCollect; + +mod try_concat; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_concat::TryConcat; + +#[cfg(feature = "alloc")] +mod try_chunks; +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_chunks::{TryChunks, TryChunksError}; + +mod try_fold; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_fold::TryFold; + +mod try_unfold; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_unfold::{try_unfold, TryUnfold}; + +mod try_skip_while; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_skip_while::TrySkipWhile; + +mod try_take_while; +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_take_while::TryTakeWhile; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod try_buffer_unordered; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_buffer_unordered::TryBufferUnordered; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod try_buffered; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_buffered::TryBuffered; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +mod try_for_each_concurrent; +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::try_for_each_concurrent::TryForEachConcurrent; + +#[cfg(feature = "io")] +#[cfg(feature = "std")] +mod into_async_read; +#[cfg(feature = "io")] +#[cfg_attr(docsrs, doc(cfg(feature = "io")))] +#[cfg(feature = "std")] +#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411 +pub use self::into_async_read::IntoAsyncRead; + +impl<S: ?Sized + TryStream> TryStreamExt for S {} + +/// Adapters specific to `Result`-returning streams +pub trait TryStreamExt: TryStream { + /// Wraps the current stream in a new stream which converts the error type + /// into the one provided. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, TryStreamExt}; + /// + /// let mut stream = + /// stream::iter(vec![Ok(()), Err(5i32)]) + /// .err_into::<i64>(); + /// + /// assert_eq!(stream.try_next().await, Ok(Some(()))); + /// assert_eq!(stream.try_next().await, Err(5i64)); + /// # }) + /// ``` + fn err_into<E>(self) -> ErrInto<Self, E> + where + Self: Sized, + Self::Error: Into<E>, + { + assert_stream::<Result<Self::Ok, E>, _>(ErrInto::new(self)) + } + + /// Wraps the current stream in a new stream which maps the success value + /// using the provided closure. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, TryStreamExt}; + /// + /// let mut stream = + /// stream::iter(vec![Ok(5), Err(0)]) + /// .map_ok(|x| x + 2); + /// + /// assert_eq!(stream.try_next().await, Ok(Some(7))); + /// assert_eq!(stream.try_next().await, Err(0)); + /// # }) + /// ``` + fn map_ok<T, F>(self, f: F) -> MapOk<Self, F> + where + Self: Sized, + F: FnMut(Self::Ok) -> T, + { + assert_stream::<Result<T, Self::Error>, _>(MapOk::new(self, f)) + } + + /// Wraps the current stream in a new stream which maps the error value + /// using the provided closure. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, TryStreamExt}; + /// + /// let mut stream = + /// stream::iter(vec![Ok(5), Err(0)]) + /// .map_err(|x| x + 2); + /// + /// assert_eq!(stream.try_next().await, Ok(Some(5))); + /// assert_eq!(stream.try_next().await, Err(2)); + /// # }) + /// ``` + fn map_err<E, F>(self, f: F) -> MapErr<Self, F> + where + Self: Sized, + F: FnMut(Self::Error) -> E, + { + assert_stream::<Result<Self::Ok, E>, _>(MapErr::new(self, f)) + } + + /// Chain on a computation for when a value is ready, passing the successful + /// results to the provided closure `f`. + /// + /// This function can be used to run a unit of work when the next successful + /// value on a stream is ready. The closure provided will be yielded a value + /// when ready, and the returned future will then be run to completion to + /// produce the next value on this stream. + /// + /// Any errors produced by this stream will not be passed to the closure, + /// and will be passed through. + /// + /// The returned value of the closure must implement the `TryFuture` trait + /// and can represent some more work to be done before the composed stream + /// is finished. + /// + /// Note that this function consumes the receiving stream and returns a + /// wrapped version of it. + /// + /// To process the entire stream and return a single future representing + /// success or error, use `try_for_each` instead. + /// + /// # Examples + /// + /// ``` + /// use futures::channel::mpsc; + /// use futures::future; + /// use futures::stream::TryStreamExt; + /// + /// let (_tx, rx) = mpsc::channel::<Result<i32, ()>>(1); + /// + /// let rx = rx.and_then(|result| { + /// future::ok(if result % 2 == 0 { + /// Some(result) + /// } else { + /// None + /// }) + /// }); + /// ``` + fn and_then<Fut, F>(self, f: F) -> AndThen<Self, Fut, F> + where + F: FnMut(Self::Ok) -> Fut, + Fut: TryFuture<Error = Self::Error>, + Self: Sized, + { + assert_stream::<Result<Fut::Ok, Fut::Error>, _>(AndThen::new(self, f)) + } + + /// Chain on a computation for when an error happens, passing the + /// erroneous result to the provided closure `f`. + /// + /// This function can be used to run a unit of work and attempt to recover from + /// an error if one happens. The closure provided will be yielded an error + /// when one appears, and the returned future will then be run to completion + /// to produce the next value on this stream. + /// + /// Any successful values produced by this stream will not be passed to the + /// closure, and will be passed through. + /// + /// The returned value of the closure must implement the [`TryFuture`](futures_core::future::TryFuture) trait + /// and can represent some more work to be done before the composed stream + /// is finished. + /// + /// Note that this function consumes the receiving stream and returns a + /// wrapped version of it. + fn or_else<Fut, F>(self, f: F) -> OrElse<Self, Fut, F> + where + F: FnMut(Self::Error) -> Fut, + Fut: TryFuture<Ok = Self::Ok>, + Self: Sized, + { + assert_stream::<Result<Self::Ok, Fut::Error>, _>(OrElse::new(self, f)) + } + + /// Do something with the success value of this stream, afterwards passing + /// it on. + /// + /// This is similar to the `StreamExt::inspect` method where it allows + /// easily inspecting the success value as it passes through the stream, for + /// example to debug what's going on. + fn inspect_ok<F>(self, f: F) -> InspectOk<Self, F> + where + F: FnMut(&Self::Ok), + Self: Sized, + { + assert_stream::<Result<Self::Ok, Self::Error>, _>(InspectOk::new(self, f)) + } + + /// Do something with the error value of this stream, afterwards passing it on. + /// + /// This is similar to the `StreamExt::inspect` method where it allows + /// easily inspecting the error value as it passes through the stream, for + /// example to debug what's going on. + fn inspect_err<F>(self, f: F) -> InspectErr<Self, F> + where + F: FnMut(&Self::Error), + Self: Sized, + { + assert_stream::<Result<Self::Ok, Self::Error>, _>(InspectErr::new(self, f)) + } + + /// Wraps a [`TryStream`] into a type that implements + /// [`Stream`](futures_core::stream::Stream) + /// + /// [`TryStream`]s currently do not implement the + /// [`Stream`](futures_core::stream::Stream) trait because of limitations + /// of the compiler. + /// + /// # Examples + /// + /// ``` + /// use futures::stream::{Stream, TryStream, TryStreamExt}; + /// + /// # type T = i32; + /// # type E = (); + /// fn make_try_stream() -> impl TryStream<Ok = T, Error = E> { // ... } + /// # futures::stream::empty() + /// # } + /// fn take_stream(stream: impl Stream<Item = Result<T, E>>) { /* ... */ } + /// + /// take_stream(make_try_stream().into_stream()); + /// ``` + fn into_stream(self) -> IntoStream<Self> + where + Self: Sized, + { + assert_stream::<Result<Self::Ok, Self::Error>, _>(IntoStream::new(self)) + } + + /// Creates a future that attempts to resolve the next item in the stream. + /// If an error is encountered before the next item, the error is returned + /// instead. + /// + /// This is similar to the `Stream::next` combinator, but returns a + /// `Result<Option<T>, E>` rather than an `Option<Result<T, E>>`, making + /// for easy use with the `?` operator. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, TryStreamExt}; + /// + /// let mut stream = stream::iter(vec![Ok(()), Err(())]); + /// + /// assert_eq!(stream.try_next().await, Ok(Some(()))); + /// assert_eq!(stream.try_next().await, Err(())); + /// # }) + /// ``` + fn try_next(&mut self) -> TryNext<'_, Self> + where + Self: Unpin, + { + assert_future::<Result<Option<Self::Ok>, Self::Error>, _>(TryNext::new(self)) + } + + /// Attempts to run this stream to completion, executing the provided + /// asynchronous closure for each element on the stream. + /// + /// The provided closure will be called for each item this stream produces, + /// yielding a future. That future will then be executed to completion + /// before moving on to the next item. + /// + /// The returned value is a [`Future`](futures_core::future::Future) where the + /// [`Output`](futures_core::future::Future::Output) type is + /// `Result<(), Self::Error>`. If any of the intermediate + /// futures or the stream returns an error, this future will return + /// immediately with an error. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, TryStreamExt}; + /// + /// let mut x = 0i32; + /// + /// { + /// let fut = stream::repeat(Ok(1)).try_for_each(|item| { + /// x += item; + /// future::ready(if x == 3 { Err(()) } else { Ok(()) }) + /// }); + /// assert_eq!(fut.await, Err(())); + /// } + /// + /// assert_eq!(x, 3); + /// # }) + /// ``` + fn try_for_each<Fut, F>(self, f: F) -> TryForEach<Self, Fut, F> + where + F: FnMut(Self::Ok) -> Fut, + Fut: TryFuture<Ok = (), Error = Self::Error>, + Self: Sized, + { + assert_future::<Result<(), Self::Error>, _>(TryForEach::new(self, f)) + } + + /// Skip elements on this stream while the provided asynchronous predicate + /// resolves to `true`. + /// + /// This function is similar to + /// [`StreamExt::skip_while`](crate::stream::StreamExt::skip_while) but exits + /// early if an error occurs. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, TryStreamExt}; + /// + /// let stream = stream::iter(vec![Ok::<i32, i32>(1), Ok(3), Ok(2)]); + /// let stream = stream.try_skip_while(|x| future::ready(Ok(*x < 3))); + /// + /// let output: Result<Vec<i32>, i32> = stream.try_collect().await; + /// assert_eq!(output, Ok(vec![3, 2])); + /// # }) + /// ``` + fn try_skip_while<Fut, F>(self, f: F) -> TrySkipWhile<Self, Fut, F> + where + F: FnMut(&Self::Ok) -> Fut, + Fut: TryFuture<Ok = bool, Error = Self::Error>, + Self: Sized, + { + assert_stream::<Result<Self::Ok, Self::Error>, _>(TrySkipWhile::new(self, f)) + } + + /// Take elements on this stream while the provided asynchronous predicate + /// resolves to `true`. + /// + /// This function is similar to + /// [`StreamExt::take_while`](crate::stream::StreamExt::take_while) but exits + /// early if an error occurs. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, TryStreamExt}; + /// + /// let stream = stream::iter(vec![Ok::<i32, i32>(1), Ok(2), Ok(3), Ok(2)]); + /// let stream = stream.try_take_while(|x| future::ready(Ok(*x < 3))); + /// + /// let output: Result<Vec<i32>, i32> = stream.try_collect().await; + /// assert_eq!(output, Ok(vec![1, 2])); + /// # }) + /// ``` + fn try_take_while<Fut, F>(self, f: F) -> TryTakeWhile<Self, Fut, F> + where + F: FnMut(&Self::Ok) -> Fut, + Fut: TryFuture<Ok = bool, Error = Self::Error>, + Self: Sized, + { + assert_stream::<Result<Self::Ok, Self::Error>, _>(TryTakeWhile::new(self, f)) + } + + /// Attempts to run this stream to completion, executing the provided asynchronous + /// closure for each element on the stream concurrently as elements become + /// available, exiting as soon as an error occurs. + /// + /// This is similar to + /// [`StreamExt::for_each_concurrent`](crate::stream::StreamExt::for_each_concurrent), + /// but will resolve to an error immediately if the underlying stream or the provided + /// closure return an error. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::oneshot; + /// use futures::stream::{self, StreamExt, TryStreamExt}; + /// + /// let (tx1, rx1) = oneshot::channel(); + /// let (tx2, rx2) = oneshot::channel(); + /// let (_tx3, rx3) = oneshot::channel(); + /// + /// let stream = stream::iter(vec![rx1, rx2, rx3]); + /// let fut = stream.map(Ok).try_for_each_concurrent( + /// /* limit */ 2, + /// |rx| async move { + /// let res: Result<(), oneshot::Canceled> = rx.await; + /// res + /// } + /// ); + /// + /// tx1.send(()).unwrap(); + /// // Drop the second sender so that `rx2` resolves to `Canceled`. + /// drop(tx2); + /// + /// // The final result is an error because the second future + /// // resulted in an error. + /// assert_eq!(Err(oneshot::Canceled), fut.await); + /// # }) + /// ``` + #[cfg(not(futures_no_atomic_cas))] + #[cfg(feature = "alloc")] + fn try_for_each_concurrent<Fut, F>( + self, + limit: impl Into<Option<usize>>, + f: F, + ) -> TryForEachConcurrent<Self, Fut, F> + where + F: FnMut(Self::Ok) -> Fut, + Fut: Future<Output = Result<(), Self::Error>>, + Self: Sized, + { + assert_future::<Result<(), Self::Error>, _>(TryForEachConcurrent::new( + self, + limit.into(), + f, + )) + } + + /// Attempt to transform a stream into a collection, + /// returning a future representing the result of that computation. + /// + /// This combinator will collect all successful results of this stream and + /// collect them into the specified collection type. If an error happens then all + /// collected elements will be dropped and the error will be returned. + /// + /// The returned future will be resolved when the stream terminates. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::TryStreamExt; + /// use std::thread; + /// + /// let (tx, rx) = mpsc::unbounded(); + /// + /// thread::spawn(move || { + /// for i in 1..=5 { + /// tx.unbounded_send(Ok(i)).unwrap(); + /// } + /// tx.unbounded_send(Err(6)).unwrap(); + /// }); + /// + /// let output: Result<Vec<i32>, i32> = rx.try_collect().await; + /// assert_eq!(output, Err(6)); + /// # }) + /// ``` + fn try_collect<C: Default + Extend<Self::Ok>>(self) -> TryCollect<Self, C> + where + Self: Sized, + { + assert_future::<Result<C, Self::Error>, _>(TryCollect::new(self)) + } + + /// An adaptor for chunking up successful items of the stream inside a vector. + /// + /// This combinator will attempt to pull successful items from this stream and buffer + /// them into a local vector. At most `capacity` items will get buffered + /// before they're yielded from the returned stream. + /// + /// Note that the vectors returned from this iterator may not always have + /// `capacity` elements. If the underlying stream ended and only a partial + /// vector was created, it'll be returned. Additionally if an error happens + /// from the underlying stream then the currently buffered items will be + /// yielded. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + /// + /// This function is similar to + /// [`StreamExt::chunks`](crate::stream::StreamExt::chunks) but exits + /// early if an error occurs. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, TryChunksError, TryStreamExt}; + /// + /// let stream = stream::iter(vec![Ok::<i32, i32>(1), Ok(2), Ok(3), Err(4), Ok(5), Ok(6)]); + /// let mut stream = stream.try_chunks(2); + /// + /// assert_eq!(stream.try_next().await, Ok(Some(vec![1, 2]))); + /// assert_eq!(stream.try_next().await, Err(TryChunksError(vec![3], 4))); + /// assert_eq!(stream.try_next().await, Ok(Some(vec![5, 6]))); + /// # }) + /// ``` + /// + /// # Panics + /// + /// This method will panic if `capacity` is zero. + #[cfg(feature = "alloc")] + fn try_chunks(self, capacity: usize) -> TryChunks<Self> + where + Self: Sized, + { + assert_stream::<Result<Vec<Self::Ok>, TryChunksError<Self::Ok, Self::Error>>, _>( + TryChunks::new(self, capacity), + ) + } + + /// Attempt to filter the values produced by this stream according to the + /// provided asynchronous closure. + /// + /// As values of this stream are made available, the provided predicate `f` + /// will be run on them. If the predicate returns a `Future` which resolves + /// to `true`, then the stream will yield the value, but if the predicate + /// return a `Future` which resolves to `false`, then the value will be + /// discarded and the next value will be produced. + /// + /// All errors are passed through without filtering in this combinator. + /// + /// Note that this function consumes the stream passed into it and returns a + /// wrapped version of it, similar to the existing `filter` methods in + /// the standard library. + /// + /// # Examples + /// ``` + /// # futures::executor::block_on(async { + /// use futures::future; + /// use futures::stream::{self, StreamExt, TryStreamExt}; + /// + /// let stream = stream::iter(vec![Ok(1i32), Ok(2i32), Ok(3i32), Err("error")]); + /// let mut evens = stream.try_filter(|x| { + /// future::ready(x % 2 == 0) + /// }); + /// + /// assert_eq!(evens.next().await, Some(Ok(2))); + /// assert_eq!(evens.next().await, Some(Err("error"))); + /// # }) + /// ``` + fn try_filter<Fut, F>(self, f: F) -> TryFilter<Self, Fut, F> + where + Fut: Future<Output = bool>, + F: FnMut(&Self::Ok) -> Fut, + Self: Sized, + { + assert_stream::<Result<Self::Ok, Self::Error>, _>(TryFilter::new(self, f)) + } + + /// Attempt to filter the values produced by this stream while + /// simultaneously mapping them to a different type according to the + /// provided asynchronous closure. + /// + /// As values of this stream are made available, the provided function will + /// be run on them. If the future returned by the predicate `f` resolves to + /// [`Some(item)`](Some) then the stream will yield the value `item`, but if + /// it resolves to [`None`] then the next value will be produced. + /// + /// All errors are passed through without filtering in this combinator. + /// + /// Note that this function consumes the stream passed into it and returns a + /// wrapped version of it, similar to the existing `filter_map` methods in + /// the standard library. + /// + /// # Examples + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, StreamExt, TryStreamExt}; + /// use futures::pin_mut; + /// + /// let stream = stream::iter(vec![Ok(1i32), Ok(6i32), Err("error")]); + /// let halves = stream.try_filter_map(|x| async move { + /// let ret = if x % 2 == 0 { Some(x / 2) } else { None }; + /// Ok(ret) + /// }); + /// + /// pin_mut!(halves); + /// assert_eq!(halves.next().await, Some(Ok(3))); + /// assert_eq!(halves.next().await, Some(Err("error"))); + /// # }) + /// ``` + fn try_filter_map<Fut, F, T>(self, f: F) -> TryFilterMap<Self, Fut, F> + where + Fut: TryFuture<Ok = Option<T>, Error = Self::Error>, + F: FnMut(Self::Ok) -> Fut, + Self: Sized, + { + assert_stream::<Result<T, Self::Error>, _>(TryFilterMap::new(self, f)) + } + + /// Flattens a stream of streams into just one continuous stream. + /// + /// If this stream's elements are themselves streams then this combinator + /// will flatten out the entire stream to one long chain of elements. Any + /// errors are passed through without looking at them, but otherwise each + /// individual stream will get exhausted before moving on to the next. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::{StreamExt, TryStreamExt}; + /// use std::thread; + /// + /// let (tx1, rx1) = mpsc::unbounded(); + /// let (tx2, rx2) = mpsc::unbounded(); + /// let (tx3, rx3) = mpsc::unbounded(); + /// + /// thread::spawn(move || { + /// tx1.unbounded_send(Ok(1)).unwrap(); + /// }); + /// thread::spawn(move || { + /// tx2.unbounded_send(Ok(2)).unwrap(); + /// tx2.unbounded_send(Err(3)).unwrap(); + /// tx2.unbounded_send(Ok(4)).unwrap(); + /// }); + /// thread::spawn(move || { + /// tx3.unbounded_send(Ok(rx1)).unwrap(); + /// tx3.unbounded_send(Ok(rx2)).unwrap(); + /// tx3.unbounded_send(Err(5)).unwrap(); + /// }); + /// + /// let mut stream = rx3.try_flatten(); + /// assert_eq!(stream.next().await, Some(Ok(1))); + /// assert_eq!(stream.next().await, Some(Ok(2))); + /// assert_eq!(stream.next().await, Some(Err(3))); + /// assert_eq!(stream.next().await, Some(Ok(4))); + /// assert_eq!(stream.next().await, Some(Err(5))); + /// assert_eq!(stream.next().await, None); + /// # }); + /// ``` + fn try_flatten(self) -> TryFlatten<Self> + where + Self::Ok: TryStream, + <Self::Ok as TryStream>::Error: From<Self::Error>, + Self: Sized, + { + assert_stream::<Result<<Self::Ok as TryStream>::Ok, <Self::Ok as TryStream>::Error>, _>( + TryFlatten::new(self), + ) + } + + /// Attempt to execute an accumulating asynchronous computation over a + /// stream, collecting all the values into one final result. + /// + /// This combinator will accumulate all values returned by this stream + /// according to the closure provided. The initial state is also provided to + /// this method and then is returned again by each execution of the closure. + /// Once the entire stream has been exhausted the returned future will + /// resolve to this value. + /// + /// This method is similar to [`fold`](crate::stream::StreamExt::fold), but will + /// exit early if an error is encountered in either the stream or the + /// provided closure. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, TryStreamExt}; + /// + /// let number_stream = stream::iter(vec![Ok::<i32, i32>(1), Ok(2)]); + /// let sum = number_stream.try_fold(0, |acc, x| async move { Ok(acc + x) }); + /// assert_eq!(sum.await, Ok(3)); + /// + /// let number_stream_with_err = stream::iter(vec![Ok::<i32, i32>(1), Err(2), Ok(1)]); + /// let sum = number_stream_with_err.try_fold(0, |acc, x| async move { Ok(acc + x) }); + /// assert_eq!(sum.await, Err(2)); + /// # }) + /// ``` + fn try_fold<T, Fut, F>(self, init: T, f: F) -> TryFold<Self, Fut, T, F> + where + F: FnMut(T, Self::Ok) -> Fut, + Fut: TryFuture<Ok = T, Error = Self::Error>, + Self: Sized, + { + assert_future::<Result<T, Self::Error>, _>(TryFold::new(self, f, init)) + } + + /// Attempt to concatenate all items of a stream into a single + /// extendable destination, returning a future representing the end result. + /// + /// This combinator will extend the first item with the contents of all + /// the subsequent successful results of the stream. If the stream is empty, + /// the default value will be returned. + /// + /// Works with all collections that implement the [`Extend`](std::iter::Extend) trait. + /// + /// This method is similar to [`concat`](crate::stream::StreamExt::concat), but will + /// exit early if an error is encountered in the stream. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::TryStreamExt; + /// use std::thread; + /// + /// let (tx, rx) = mpsc::unbounded::<Result<Vec<i32>, ()>>(); + /// + /// thread::spawn(move || { + /// for i in (0..3).rev() { + /// let n = i * 3; + /// tx.unbounded_send(Ok(vec![n + 1, n + 2, n + 3])).unwrap(); + /// } + /// }); + /// + /// let result = rx.try_concat().await; + /// + /// assert_eq!(result, Ok(vec![7, 8, 9, 4, 5, 6, 1, 2, 3])); + /// # }); + /// ``` + fn try_concat(self) -> TryConcat<Self> + where + Self: Sized, + Self::Ok: Extend<<<Self as TryStream>::Ok as IntoIterator>::Item> + IntoIterator + Default, + { + assert_future::<Result<Self::Ok, Self::Error>, _>(TryConcat::new(self)) + } + + /// Attempt to execute several futures from a stream concurrently (unordered). + /// + /// This stream's `Ok` type must be a [`TryFuture`](futures_core::future::TryFuture) with an `Error` type + /// that matches the stream's `Error` type. + /// + /// This adaptor will buffer up to `n` futures and then return their + /// outputs in the order in which they complete. If the underlying stream + /// returns an error, it will be immediately propagated. + /// + /// The returned stream will be a stream of results, each containing either + /// an error or a future's output. An error can be produced either by the + /// underlying stream itself or by one of the futures it yielded. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + /// + /// # Examples + /// + /// Results are returned in the order of completion: + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::oneshot; + /// use futures::stream::{self, StreamExt, TryStreamExt}; + /// + /// let (send_one, recv_one) = oneshot::channel(); + /// let (send_two, recv_two) = oneshot::channel(); + /// + /// let stream_of_futures = stream::iter(vec![Ok(recv_one), Ok(recv_two)]); + /// + /// let mut buffered = stream_of_futures.try_buffer_unordered(10); + /// + /// send_two.send(2i32)?; + /// assert_eq!(buffered.next().await, Some(Ok(2i32))); + /// + /// send_one.send(1i32)?; + /// assert_eq!(buffered.next().await, Some(Ok(1i32))); + /// + /// assert_eq!(buffered.next().await, None); + /// # Ok::<(), i32>(()) }).unwrap(); + /// ``` + /// + /// Errors from the underlying stream itself are propagated: + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::{StreamExt, TryStreamExt}; + /// + /// let (sink, stream_of_futures) = mpsc::unbounded(); + /// let mut buffered = stream_of_futures.try_buffer_unordered(10); + /// + /// sink.unbounded_send(Ok(async { Ok(7i32) }))?; + /// assert_eq!(buffered.next().await, Some(Ok(7i32))); + /// + /// sink.unbounded_send(Err("error in the stream"))?; + /// assert_eq!(buffered.next().await, Some(Err("error in the stream"))); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + #[cfg(not(futures_no_atomic_cas))] + #[cfg(feature = "alloc")] + fn try_buffer_unordered(self, n: usize) -> TryBufferUnordered<Self> + where + Self::Ok: TryFuture<Error = Self::Error>, + Self: Sized, + { + assert_stream::<Result<<Self::Ok as TryFuture>::Ok, Self::Error>, _>( + TryBufferUnordered::new(self, n), + ) + } + + /// Attempt to execute several futures from a stream concurrently. + /// + /// This stream's `Ok` type must be a [`TryFuture`](futures_core::future::TryFuture) with an `Error` type + /// that matches the stream's `Error` type. + /// + /// This adaptor will buffer up to `n` futures and then return their + /// outputs in the same order as the underlying stream. If the underlying stream returns an error, it will + /// be immediately propagated. + /// + /// The returned stream will be a stream of results, each containing either + /// an error or a future's output. An error can be produced either by the + /// underlying stream itself or by one of the futures it yielded. + /// + /// This method is only available when the `std` or `alloc` feature of this + /// library is activated, and it is activated by default. + /// + /// # Examples + /// + /// Results are returned in the order of addition: + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::oneshot; + /// use futures::future::lazy; + /// use futures::stream::{self, StreamExt, TryStreamExt}; + /// + /// let (send_one, recv_one) = oneshot::channel(); + /// let (send_two, recv_two) = oneshot::channel(); + /// + /// let mut buffered = lazy(move |cx| { + /// let stream_of_futures = stream::iter(vec![Ok(recv_one), Ok(recv_two)]); + /// + /// let mut buffered = stream_of_futures.try_buffered(10); + /// + /// assert!(buffered.try_poll_next_unpin(cx).is_pending()); + /// + /// send_two.send(2i32)?; + /// assert!(buffered.try_poll_next_unpin(cx).is_pending()); + /// Ok::<_, i32>(buffered) + /// }).await?; + /// + /// send_one.send(1i32)?; + /// assert_eq!(buffered.next().await, Some(Ok(1i32))); + /// assert_eq!(buffered.next().await, Some(Ok(2i32))); + /// + /// assert_eq!(buffered.next().await, None); + /// # Ok::<(), i32>(()) }).unwrap(); + /// ``` + /// + /// Errors from the underlying stream itself are propagated: + /// ``` + /// # futures::executor::block_on(async { + /// use futures::channel::mpsc; + /// use futures::stream::{StreamExt, TryStreamExt}; + /// + /// let (sink, stream_of_futures) = mpsc::unbounded(); + /// let mut buffered = stream_of_futures.try_buffered(10); + /// + /// sink.unbounded_send(Ok(async { Ok(7i32) }))?; + /// assert_eq!(buffered.next().await, Some(Ok(7i32))); + /// + /// sink.unbounded_send(Err("error in the stream"))?; + /// assert_eq!(buffered.next().await, Some(Err("error in the stream"))); + /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); + /// ``` + #[cfg(not(futures_no_atomic_cas))] + #[cfg(feature = "alloc")] + fn try_buffered(self, n: usize) -> TryBuffered<Self> + where + Self::Ok: TryFuture<Error = Self::Error>, + Self: Sized, + { + assert_stream::<Result<<Self::Ok as TryFuture>::Ok, Self::Error>, _>(TryBuffered::new( + self, n, + )) + } + + // TODO: false positive warning from rustdoc. Verify once #43466 settles + // + /// A convenience method for calling [`TryStream::try_poll_next`] on [`Unpin`] + /// stream types. + fn try_poll_next_unpin( + &mut self, + cx: &mut Context<'_>, + ) -> Poll<Option<Result<Self::Ok, Self::Error>>> + where + Self: Unpin, + { + Pin::new(self).try_poll_next(cx) + } + + /// Wraps a [`TryStream`] into a stream compatible with libraries using + /// futures 0.1 `Stream`. Requires the `compat` feature to be enabled. + /// ``` + /// # if cfg!(miri) { return; } // Miri does not support epoll + /// use futures::future::{FutureExt, TryFutureExt}; + /// # let (tx, rx) = futures::channel::oneshot::channel(); + /// + /// let future03 = async { + /// println!("Running on the pool"); + /// tx.send(42).unwrap(); + /// }; + /// + /// let future01 = future03 + /// .unit_error() // Make it a TryFuture + /// .boxed() // Make it Unpin + /// .compat(); + /// + /// tokio::run(future01); + /// # assert_eq!(42, futures::executor::block_on(rx).unwrap()); + /// ``` + #[cfg(feature = "compat")] + #[cfg_attr(docsrs, doc(cfg(feature = "compat")))] + fn compat(self) -> Compat<Self> + where + Self: Sized + Unpin, + { + Compat::new(self) + } + + /// Adapter that converts this stream into an [`AsyncBufRead`](crate::io::AsyncBufRead). + /// + /// This method is only available when the `std` feature of this + /// library is activated, and it is activated by default. + /// + /// # Examples + /// + /// ``` + /// # futures::executor::block_on(async { + /// use futures::stream::{self, TryStreamExt}; + /// use futures::io::AsyncReadExt; + /// + /// let stream = stream::iter([Ok(vec![1, 2, 3]), Ok(vec![4, 5])]); + /// let mut reader = stream.into_async_read(); + /// + /// let mut buf = Vec::new(); + /// reader.read_to_end(&mut buf).await.unwrap(); + /// assert_eq!(buf, [1, 2, 3, 4, 5]); + /// # }) + /// ``` + #[cfg(feature = "io")] + #[cfg_attr(docsrs, doc(cfg(feature = "io")))] + #[cfg(feature = "std")] + fn into_async_read(self) -> IntoAsyncRead<Self> + where + Self: Sized + TryStreamExt<Error = std::io::Error>, + Self::Ok: AsRef<[u8]>, + { + crate::io::assert_read(IntoAsyncRead::new(self)) + } +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/or_else.rs b/third_party/rust/futures-util/src/stream/try_stream/or_else.rs new file mode 100644 index 0000000000..53aceb8e64 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/or_else.rs @@ -0,0 +1,109 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::TryFuture; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`or_else`](super::TryStreamExt::or_else) method. + #[must_use = "streams do nothing unless polled"] + pub struct OrElse<St, Fut, F> { + #[pin] + stream: St, + #[pin] + future: Option<Fut>, + f: F, + } +} + +impl<St, Fut, F> fmt::Debug for OrElse<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("OrElse") + .field("stream", &self.stream) + .field("future", &self.future) + .finish() + } +} + +impl<St, Fut, F> OrElse<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Error) -> Fut, + Fut: TryFuture<Ok = St::Ok>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, future: None, f } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> Stream for OrElse<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Error) -> Fut, + Fut: TryFuture<Ok = St::Ok>, +{ + type Item = Result<St::Ok, Fut::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + let item = ready!(fut.try_poll(cx)); + this.future.set(None); + break Some(item); + } else { + match ready!(this.stream.as_mut().try_poll_next(cx)) { + Some(Ok(item)) => break Some(Ok(item)), + Some(Err(e)) => { + this.future.set(Some((this.f)(e))); + } + None => break None, + } + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let future_len = usize::from(self.future.is_some()); + let (lower, upper) = self.stream.size_hint(); + let lower = lower.saturating_add(future_len); + let upper = match upper { + Some(x) => x.checked_add(future_len), + None => None, + }; + (lower, upper) + } +} + +impl<St, Fut, F> FusedStream for OrElse<St, Fut, F> +where + St: TryStream + FusedStream, + F: FnMut(St::Error) -> Fut, + Fut: TryFuture<Ok = St::Ok>, +{ + fn is_terminated(&self) -> bool { + self.future.is_none() && self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item> Sink<Item> for OrElse<S, Fut, F> +where + S: Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_buffer_unordered.rs b/third_party/rust/futures-util/src/stream/try_stream/try_buffer_unordered.rs new file mode 100644 index 0000000000..9a899d4ea6 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_buffer_unordered.rs @@ -0,0 +1,86 @@ +use crate::future::{IntoFuture, TryFutureExt}; +use crate::stream::{Fuse, FuturesUnordered, IntoStream, StreamExt}; +use core::pin::Pin; +use futures_core::future::TryFuture; +use futures_core::stream::{Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the + /// [`try_buffer_unordered`](super::TryStreamExt::try_buffer_unordered) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct TryBufferUnordered<St> + where St: TryStream + { + #[pin] + stream: Fuse<IntoStream<St>>, + in_progress_queue: FuturesUnordered<IntoFuture<St::Ok>>, + max: usize, + } +} + +impl<St> TryBufferUnordered<St> +where + St: TryStream, + St::Ok: TryFuture, +{ + pub(super) fn new(stream: St, n: usize) -> Self { + Self { + stream: IntoStream::new(stream).fuse(), + in_progress_queue: FuturesUnordered::new(), + max: n, + } + } + + delegate_access_inner!(stream, St, (. .)); +} + +impl<St> Stream for TryBufferUnordered<St> +where + St: TryStream, + St::Ok: TryFuture<Error = St::Error>, +{ + type Item = Result<<St::Ok as TryFuture>::Ok, St::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + // First up, try to spawn off as many futures as possible by filling up + // our queue of futures. Propagate errors from the stream immediately. + while this.in_progress_queue.len() < *this.max { + match this.stream.as_mut().poll_next(cx)? { + Poll::Ready(Some(fut)) => this.in_progress_queue.push(fut.into_future()), + Poll::Ready(None) | Poll::Pending => break, + } + } + + // Attempt to pull the next value from the in_progress_queue + match this.in_progress_queue.poll_next_unpin(cx) { + x @ Poll::Pending | x @ Poll::Ready(Some(_)) => return x, + Poll::Ready(None) => {} + } + + // If more values are still coming from the stream, we're not done yet + if this.stream.is_done() { + Poll::Ready(None) + } else { + Poll::Pending + } + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item, E> Sink<Item> for TryBufferUnordered<S> +where + S: TryStream + Sink<Item, Error = E>, + S::Ok: TryFuture<Error = E>, +{ + type Error = E; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_buffered.rs b/third_party/rust/futures-util/src/stream/try_stream/try_buffered.rs new file mode 100644 index 0000000000..9f48e5c0a7 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_buffered.rs @@ -0,0 +1,87 @@ +use crate::future::{IntoFuture, TryFutureExt}; +use crate::stream::{Fuse, FuturesOrdered, IntoStream, StreamExt}; +use core::pin::Pin; +use futures_core::future::TryFuture; +use futures_core::stream::{Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`try_buffered`](super::TryStreamExt::try_buffered) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct TryBuffered<St> + where + St: TryStream, + St::Ok: TryFuture, + { + #[pin] + stream: Fuse<IntoStream<St>>, + in_progress_queue: FuturesOrdered<IntoFuture<St::Ok>>, + max: usize, + } +} + +impl<St> TryBuffered<St> +where + St: TryStream, + St::Ok: TryFuture, +{ + pub(super) fn new(stream: St, n: usize) -> Self { + Self { + stream: IntoStream::new(stream).fuse(), + in_progress_queue: FuturesOrdered::new(), + max: n, + } + } + + delegate_access_inner!(stream, St, (. .)); +} + +impl<St> Stream for TryBuffered<St> +where + St: TryStream, + St::Ok: TryFuture<Error = St::Error>, +{ + type Item = Result<<St::Ok as TryFuture>::Ok, St::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + // First up, try to spawn off as many futures as possible by filling up + // our queue of futures. Propagate errors from the stream immediately. + while this.in_progress_queue.len() < *this.max { + match this.stream.as_mut().poll_next(cx)? { + Poll::Ready(Some(fut)) => this.in_progress_queue.push_back(fut.into_future()), + Poll::Ready(None) | Poll::Pending => break, + } + } + + // Attempt to pull the next value from the in_progress_queue + match this.in_progress_queue.poll_next_unpin(cx) { + x @ Poll::Pending | x @ Poll::Ready(Some(_)) => return x, + Poll::Ready(None) => {} + } + + // If more values are still coming from the stream, we're not done yet + if this.stream.is_done() { + Poll::Ready(None) + } else { + Poll::Pending + } + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item, E> Sink<Item> for TryBuffered<S> +where + S: TryStream + Sink<Item, Error = E>, + S::Ok: TryFuture<Error = E>, +{ + type Error = E; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_chunks.rs b/third_party/rust/futures-util/src/stream/try_stream/try_chunks.rs new file mode 100644 index 0000000000..3bb253a714 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_chunks.rs @@ -0,0 +1,131 @@ +use crate::stream::{Fuse, IntoStream, StreamExt}; + +use alloc::vec::Vec; +use core::pin::Pin; +use core::{fmt, mem}; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`try_chunks`](super::TryStreamExt::try_chunks) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct TryChunks<St: TryStream> { + #[pin] + stream: Fuse<IntoStream<St>>, + items: Vec<St::Ok>, + cap: usize, // https://github.com/rust-lang/futures-rs/issues/1475 + } +} + +impl<St: TryStream> TryChunks<St> { + pub(super) fn new(stream: St, capacity: usize) -> Self { + assert!(capacity > 0); + + Self { + stream: IntoStream::new(stream).fuse(), + items: Vec::with_capacity(capacity), + cap: capacity, + } + } + + fn take(self: Pin<&mut Self>) -> Vec<St::Ok> { + let cap = self.cap; + mem::replace(self.project().items, Vec::with_capacity(cap)) + } + + delegate_access_inner!(stream, St, (. .)); +} + +impl<St: TryStream> Stream for TryChunks<St> { + #[allow(clippy::type_complexity)] + type Item = Result<Vec<St::Ok>, TryChunksError<St::Ok, St::Error>>; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.as_mut().project(); + loop { + match ready!(this.stream.as_mut().try_poll_next(cx)) { + // Push the item into the buffer and check whether it is full. + // If so, replace our buffer with a new and empty one and return + // the full one. + Some(item) => match item { + Ok(item) => { + this.items.push(item); + if this.items.len() >= *this.cap { + return Poll::Ready(Some(Ok(self.take()))); + } + } + Err(e) => { + return Poll::Ready(Some(Err(TryChunksError(self.take(), e)))); + } + }, + + // Since the underlying stream ran out of values, return what we + // have buffered, if we have anything. + None => { + let last = if this.items.is_empty() { + None + } else { + let full_buf = mem::take(this.items); + Some(full_buf) + }; + + return Poll::Ready(last.map(Ok)); + } + } + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let chunk_len = usize::from(!self.items.is_empty()); + let (lower, upper) = self.stream.size_hint(); + let lower = (lower / self.cap).saturating_add(chunk_len); + let upper = match upper { + Some(x) => x.checked_add(chunk_len), + None => None, + }; + (lower, upper) + } +} + +impl<St: TryStream + FusedStream> FusedStream for TryChunks<St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() && self.items.is_empty() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for TryChunks<S> +where + S: TryStream + Sink<Item>, +{ + type Error = <S as Sink<Item>>::Error; + + delegate_sink!(stream, Item); +} + +/// Error indicating, that while chunk was collected inner stream produced an error. +/// +/// Contains all items that were collected before an error occurred, and the stream error itself. +#[derive(PartialEq, Eq)] +pub struct TryChunksError<T, E>(pub Vec<T>, pub E); + +impl<T, E: fmt::Debug> fmt::Debug for TryChunksError<T, E> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.1.fmt(f) + } +} + +impl<T, E: fmt::Display> fmt::Display for TryChunksError<T, E> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.1.fmt(f) + } +} + +#[cfg(feature = "std")] +impl<T, E: fmt::Debug + fmt::Display> std::error::Error for TryChunksError<T, E> {} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_collect.rs b/third_party/rust/futures-util/src/stream/try_stream/try_collect.rs new file mode 100644 index 0000000000..3e5963f033 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_collect.rs @@ -0,0 +1,52 @@ +use core::mem; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::ready; +use futures_core::stream::{FusedStream, TryStream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`try_collect`](super::TryStreamExt::try_collect) method. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct TryCollect<St, C> { + #[pin] + stream: St, + items: C, + } +} + +impl<St: TryStream, C: Default> TryCollect<St, C> { + pub(super) fn new(s: St) -> Self { + Self { stream: s, items: Default::default() } + } +} + +impl<St, C> FusedFuture for TryCollect<St, C> +where + St: TryStream + FusedStream, + C: Default + Extend<St::Ok>, +{ + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St, C> Future for TryCollect<St, C> +where + St: TryStream, + C: Default + Extend<St::Ok>, +{ + type Output = Result<C, St::Error>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut this = self.project(); + Poll::Ready(Ok(loop { + match ready!(this.stream.as_mut().try_poll_next(cx)?) { + Some(x) => this.items.extend(Some(x)), + None => break mem::take(this.items), + } + })) + } +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_concat.rs b/third_party/rust/futures-util/src/stream/try_stream/try_concat.rs new file mode 100644 index 0000000000..58fb6a5413 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_concat.rs @@ -0,0 +1,51 @@ +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::TryStream; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`try_concat`](super::TryStreamExt::try_concat) method. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct TryConcat<St: TryStream> { + #[pin] + stream: St, + accum: Option<St::Ok>, + } +} + +impl<St> TryConcat<St> +where + St: TryStream, + St::Ok: Extend<<St::Ok as IntoIterator>::Item> + IntoIterator + Default, +{ + pub(super) fn new(stream: St) -> Self { + Self { stream, accum: None } + } +} + +impl<St> Future for TryConcat<St> +where + St: TryStream, + St::Ok: Extend<<St::Ok as IntoIterator>::Item> + IntoIterator + Default, +{ + type Output = Result<St::Ok, St::Error>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut this = self.project(); + + Poll::Ready(Ok(loop { + if let Some(x) = ready!(this.stream.as_mut().try_poll_next(cx)?) { + if let Some(a) = this.accum { + a.extend(x) + } else { + *this.accum = Some(x) + } + } else { + break this.accum.take().unwrap_or_default(); + } + })) + } +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_filter.rs b/third_party/rust/futures-util/src/stream/try_stream/try_filter.rs new file mode 100644 index 0000000000..11d58243fd --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_filter.rs @@ -0,0 +1,112 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`try_filter`](super::TryStreamExt::try_filter) + /// method. + #[must_use = "streams do nothing unless polled"] + pub struct TryFilter<St, Fut, F> + where St: TryStream + { + #[pin] + stream: St, + f: F, + #[pin] + pending_fut: Option<Fut>, + pending_item: Option<St::Ok>, + } +} + +impl<St, Fut, F> fmt::Debug for TryFilter<St, Fut, F> +where + St: TryStream + fmt::Debug, + St::Ok: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TryFilter") + .field("stream", &self.stream) + .field("pending_fut", &self.pending_fut) + .field("pending_item", &self.pending_item) + .finish() + } +} + +impl<St, Fut, F> TryFilter<St, Fut, F> +where + St: TryStream, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, pending_fut: None, pending_item: None } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> FusedStream for TryFilter<St, Fut, F> +where + St: TryStream + FusedStream, + F: FnMut(&St::Ok) -> Fut, + Fut: Future<Output = bool>, +{ + fn is_terminated(&self) -> bool { + self.pending_fut.is_none() && self.stream.is_terminated() + } +} + +impl<St, Fut, F> Stream for TryFilter<St, Fut, F> +where + St: TryStream, + Fut: Future<Output = bool>, + F: FnMut(&St::Ok) -> Fut, +{ + type Item = Result<St::Ok, St::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(fut) = this.pending_fut.as_mut().as_pin_mut() { + let res = ready!(fut.poll(cx)); + this.pending_fut.set(None); + if res { + break this.pending_item.take().map(Ok); + } + *this.pending_item = None; + } else if let Some(item) = ready!(this.stream.as_mut().try_poll_next(cx)?) { + this.pending_fut.set(Some((this.f)(&item))); + *this.pending_item = Some(item); + } else { + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let pending_len = usize::from(self.pending_fut.is_some()); + let (_, upper) = self.stream.size_hint(); + let upper = match upper { + Some(x) => x.checked_add(pending_len), + None => None, + }; + (0, upper) // can't know a lower bound, due to the predicate + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item, E> Sink<Item> for TryFilter<S, Fut, F> +where + S: TryStream + Sink<Item, Error = E>, +{ + type Error = E; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_filter_map.rs b/third_party/rust/futures-util/src/stream/try_stream/try_filter_map.rs new file mode 100644 index 0000000000..ed1201732b --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_filter_map.rs @@ -0,0 +1,106 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::TryFuture; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`try_filter_map`](super::TryStreamExt::try_filter_map) + /// method. + #[must_use = "streams do nothing unless polled"] + pub struct TryFilterMap<St, Fut, F> { + #[pin] + stream: St, + f: F, + #[pin] + pending: Option<Fut>, + } +} + +impl<St, Fut, F> fmt::Debug for TryFilterMap<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TryFilterMap") + .field("stream", &self.stream) + .field("pending", &self.pending) + .finish() + } +} + +impl<St, Fut, F> TryFilterMap<St, Fut, F> { + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, pending: None } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F, T> FusedStream for TryFilterMap<St, Fut, F> +where + St: TryStream + FusedStream, + Fut: TryFuture<Ok = Option<T>, Error = St::Error>, + F: FnMut(St::Ok) -> Fut, +{ + fn is_terminated(&self) -> bool { + self.pending.is_none() && self.stream.is_terminated() + } +} + +impl<St, Fut, F, T> Stream for TryFilterMap<St, Fut, F> +where + St: TryStream, + Fut: TryFuture<Ok = Option<T>, Error = St::Error>, + F: FnMut(St::Ok) -> Fut, +{ + type Item = Result<T, St::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(p) = this.pending.as_mut().as_pin_mut() { + // We have an item in progress, poll that until it's done + let res = ready!(p.try_poll(cx)); + this.pending.set(None); + let item = res?; + if item.is_some() { + break item.map(Ok); + } + } else if let Some(item) = ready!(this.stream.as_mut().try_poll_next(cx)?) { + // No item in progress, but the stream is still going + this.pending.set(Some((this.f)(item))); + } else { + // The stream is done + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let pending_len = usize::from(self.pending.is_some()); + let (_, upper) = self.stream.size_hint(); + let upper = match upper { + Some(x) => x.checked_add(pending_len), + None => None, + }; + (0, upper) // can't know a lower bound, due to the predicate + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item> Sink<Item> for TryFilterMap<S, Fut, F> +where + S: Sink<Item>, +{ + type Error = S::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_flatten.rs b/third_party/rust/futures-util/src/stream/try_stream/try_flatten.rs new file mode 100644 index 0000000000..4fc04a07bb --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_flatten.rs @@ -0,0 +1,84 @@ +use core::pin::Pin; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`try_flatten`](super::TryStreamExt::try_flatten) method. + #[derive(Debug)] + #[must_use = "streams do nothing unless polled"] + pub struct TryFlatten<St> + where + St: TryStream, + { + #[pin] + stream: St, + #[pin] + next: Option<St::Ok>, + } +} + +impl<St> TryFlatten<St> +where + St: TryStream, + St::Ok: TryStream, + <St::Ok as TryStream>::Error: From<St::Error>, +{ + pub(super) fn new(stream: St) -> Self { + Self { stream, next: None } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St> FusedStream for TryFlatten<St> +where + St: TryStream + FusedStream, + St::Ok: TryStream, + <St::Ok as TryStream>::Error: From<St::Error>, +{ + fn is_terminated(&self) -> bool { + self.next.is_none() && self.stream.is_terminated() + } +} + +impl<St> Stream for TryFlatten<St> +where + St: TryStream, + St::Ok: TryStream, + <St::Ok as TryStream>::Error: From<St::Error>, +{ + type Item = Result<<St::Ok as TryStream>::Ok, <St::Ok as TryStream>::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(s) = this.next.as_mut().as_pin_mut() { + if let Some(item) = ready!(s.try_poll_next(cx)?) { + break Some(Ok(item)); + } else { + this.next.set(None); + } + } else if let Some(s) = ready!(this.stream.as_mut().try_poll_next(cx)?) { + this.next.set(Some(s)); + } else { + break None; + } + }) + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Item> Sink<Item> for TryFlatten<S> +where + S: TryStream + Sink<Item>, +{ + type Error = <S as Sink<Item>>::Error; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_fold.rs b/third_party/rust/futures-util/src/stream/try_stream/try_fold.rs new file mode 100644 index 0000000000..d344d96e7d --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_fold.rs @@ -0,0 +1,93 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future, TryFuture}; +use futures_core::ready; +use futures_core::stream::TryStream; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`try_fold`](super::TryStreamExt::try_fold) method. + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct TryFold<St, Fut, T, F> { + #[pin] + stream: St, + f: F, + accum: Option<T>, + #[pin] + future: Option<Fut>, + } +} + +impl<St, Fut, T, F> fmt::Debug for TryFold<St, Fut, T, F> +where + St: fmt::Debug, + Fut: fmt::Debug, + T: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TryFold") + .field("stream", &self.stream) + .field("accum", &self.accum) + .field("future", &self.future) + .finish() + } +} + +impl<St, Fut, T, F> TryFold<St, Fut, T, F> +where + St: TryStream, + F: FnMut(T, St::Ok) -> Fut, + Fut: TryFuture<Ok = T, Error = St::Error>, +{ + pub(super) fn new(stream: St, f: F, t: T) -> Self { + Self { stream, f, accum: Some(t), future: None } + } +} + +impl<St, Fut, T, F> FusedFuture for TryFold<St, Fut, T, F> +where + St: TryStream, + F: FnMut(T, St::Ok) -> Fut, + Fut: TryFuture<Ok = T, Error = St::Error>, +{ + fn is_terminated(&self) -> bool { + self.accum.is_none() && self.future.is_none() + } +} + +impl<St, Fut, T, F> Future for TryFold<St, Fut, T, F> +where + St: TryStream, + F: FnMut(T, St::Ok) -> Fut, + Fut: TryFuture<Ok = T, Error = St::Error>, +{ + type Output = Result<T, St::Error>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut this = self.project(); + + Poll::Ready(loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + // we're currently processing a future to produce a new accum value + let res = ready!(fut.try_poll(cx)); + this.future.set(None); + match res { + Ok(a) => *this.accum = Some(a), + Err(e) => break Err(e), + } + } else if this.accum.is_some() { + // we're waiting on a new item from the stream + let res = ready!(this.stream.as_mut().try_poll_next(cx)); + let a = this.accum.take().unwrap(); + match res { + Some(Ok(item)) => this.future.set(Some((this.f)(a, item))), + Some(Err(e)) => break Err(e), + None => break Ok(a), + } + } else { + panic!("Fold polled after completion") + } + }) + } +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_for_each.rs b/third_party/rust/futures-util/src/stream/try_stream/try_for_each.rs new file mode 100644 index 0000000000..6a081d84e7 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_for_each.rs @@ -0,0 +1,68 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::{Future, TryFuture}; +use futures_core::ready; +use futures_core::stream::TryStream; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the [`try_for_each`](super::TryStreamExt::try_for_each) method. + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct TryForEach<St, Fut, F> { + #[pin] + stream: St, + f: F, + #[pin] + future: Option<Fut>, + } +} + +impl<St, Fut, F> fmt::Debug for TryForEach<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TryForEach") + .field("stream", &self.stream) + .field("future", &self.future) + .finish() + } +} + +impl<St, Fut, F> TryForEach<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Ok) -> Fut, + Fut: TryFuture<Ok = (), Error = St::Error>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, future: None } + } +} + +impl<St, Fut, F> Future for TryForEach<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Ok) -> Fut, + Fut: TryFuture<Ok = (), Error = St::Error>, +{ + type Output = Result<(), St::Error>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut this = self.project(); + loop { + if let Some(fut) = this.future.as_mut().as_pin_mut() { + ready!(fut.try_poll(cx))?; + this.future.set(None); + } else { + match ready!(this.stream.as_mut().try_poll_next(cx)?) { + Some(e) => this.future.set(Some((this.f)(e))), + None => break, + } + } + } + Poll::Ready(Ok(())) + } +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_for_each_concurrent.rs b/third_party/rust/futures-util/src/stream/try_stream/try_for_each_concurrent.rs new file mode 100644 index 0000000000..62734c746b --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_for_each_concurrent.rs @@ -0,0 +1,133 @@ +use crate::stream::{FuturesUnordered, StreamExt}; +use core::fmt; +use core::mem; +use core::num::NonZeroUsize; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::stream::TryStream; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +pin_project! { + /// Future for the + /// [`try_for_each_concurrent`](super::TryStreamExt::try_for_each_concurrent) + /// method. + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct TryForEachConcurrent<St, Fut, F> { + #[pin] + stream: Option<St>, + f: F, + futures: FuturesUnordered<Fut>, + limit: Option<NonZeroUsize>, + } +} + +impl<St, Fut, F> fmt::Debug for TryForEachConcurrent<St, Fut, F> +where + St: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TryForEachConcurrent") + .field("stream", &self.stream) + .field("futures", &self.futures) + .field("limit", &self.limit) + .finish() + } +} + +impl<St, Fut, F> FusedFuture for TryForEachConcurrent<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Ok) -> Fut, + Fut: Future<Output = Result<(), St::Error>>, +{ + fn is_terminated(&self) -> bool { + self.stream.is_none() && self.futures.is_empty() + } +} + +impl<St, Fut, F> TryForEachConcurrent<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Ok) -> Fut, + Fut: Future<Output = Result<(), St::Error>>, +{ + pub(super) fn new(stream: St, limit: Option<usize>, f: F) -> Self { + Self { + stream: Some(stream), + // Note: `limit` = 0 gets ignored. + limit: limit.and_then(NonZeroUsize::new), + f, + futures: FuturesUnordered::new(), + } + } +} + +impl<St, Fut, F> Future for TryForEachConcurrent<St, Fut, F> +where + St: TryStream, + F: FnMut(St::Ok) -> Fut, + Fut: Future<Output = Result<(), St::Error>>, +{ + type Output = Result<(), St::Error>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let mut this = self.project(); + loop { + let mut made_progress_this_iter = false; + + // Check if we've already created a number of futures greater than `limit` + if this.limit.map(|limit| limit.get() > this.futures.len()).unwrap_or(true) { + let poll_res = match this.stream.as_mut().as_pin_mut() { + Some(stream) => stream.try_poll_next(cx), + None => Poll::Ready(None), + }; + + let elem = match poll_res { + Poll::Ready(Some(Ok(elem))) => { + made_progress_this_iter = true; + Some(elem) + } + Poll::Ready(None) => { + this.stream.set(None); + None + } + Poll::Pending => None, + Poll::Ready(Some(Err(e))) => { + // Empty the stream and futures so that we know + // the future has completed. + this.stream.set(None); + drop(mem::replace(this.futures, FuturesUnordered::new())); + return Poll::Ready(Err(e)); + } + }; + + if let Some(elem) = elem { + this.futures.push((this.f)(elem)); + } + } + + match this.futures.poll_next_unpin(cx) { + Poll::Ready(Some(Ok(()))) => made_progress_this_iter = true, + Poll::Ready(None) => { + if this.stream.is_none() { + return Poll::Ready(Ok(())); + } + } + Poll::Pending => {} + Poll::Ready(Some(Err(e))) => { + // Empty the stream and futures so that we know + // the future has completed. + this.stream.set(None); + drop(mem::replace(this.futures, FuturesUnordered::new())); + return Poll::Ready(Err(e)); + } + } + + if !made_progress_this_iter { + return Poll::Pending; + } + } + } +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_next.rs b/third_party/rust/futures-util/src/stream/try_stream/try_next.rs new file mode 100644 index 0000000000..13fcf80cae --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_next.rs @@ -0,0 +1,34 @@ +use crate::stream::TryStreamExt; +use core::pin::Pin; +use futures_core::future::{FusedFuture, Future}; +use futures_core::stream::{FusedStream, TryStream}; +use futures_core::task::{Context, Poll}; + +/// Future for the [`try_next`](super::TryStreamExt::try_next) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct TryNext<'a, St: ?Sized> { + stream: &'a mut St, +} + +impl<St: ?Sized + Unpin> Unpin for TryNext<'_, St> {} + +impl<'a, St: ?Sized + TryStream + Unpin> TryNext<'a, St> { + pub(super) fn new(stream: &'a mut St) -> Self { + Self { stream } + } +} + +impl<St: ?Sized + TryStream + Unpin + FusedStream> FusedFuture for TryNext<'_, St> { + fn is_terminated(&self) -> bool { + self.stream.is_terminated() + } +} + +impl<St: ?Sized + TryStream + Unpin> Future for TryNext<'_, St> { + type Output = Result<Option<St::Ok>, St::Error>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + self.stream.try_poll_next_unpin(cx)?.map(Ok) + } +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_skip_while.rs b/third_party/rust/futures-util/src/stream/try_stream/try_skip_while.rs new file mode 100644 index 0000000000..52aa2d478b --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_skip_while.rs @@ -0,0 +1,120 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::TryFuture; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`try_skip_while`](super::TryStreamExt::try_skip_while) + /// method. + #[must_use = "streams do nothing unless polled"] + pub struct TrySkipWhile<St, Fut, F> where St: TryStream { + #[pin] + stream: St, + f: F, + #[pin] + pending_fut: Option<Fut>, + pending_item: Option<St::Ok>, + done_skipping: bool, + } +} + +impl<St, Fut, F> fmt::Debug for TrySkipWhile<St, Fut, F> +where + St: TryStream + fmt::Debug, + St::Ok: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TrySkipWhile") + .field("stream", &self.stream) + .field("pending_fut", &self.pending_fut) + .field("pending_item", &self.pending_item) + .field("done_skipping", &self.done_skipping) + .finish() + } +} + +impl<St, Fut, F> TrySkipWhile<St, Fut, F> +where + St: TryStream, + F: FnMut(&St::Ok) -> Fut, + Fut: TryFuture<Ok = bool, Error = St::Error>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, pending_fut: None, pending_item: None, done_skipping: false } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> Stream for TrySkipWhile<St, Fut, F> +where + St: TryStream, + F: FnMut(&St::Ok) -> Fut, + Fut: TryFuture<Ok = bool, Error = St::Error>, +{ + type Item = Result<St::Ok, St::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + if *this.done_skipping { + return this.stream.try_poll_next(cx); + } + + Poll::Ready(loop { + if let Some(fut) = this.pending_fut.as_mut().as_pin_mut() { + let res = ready!(fut.try_poll(cx)); + this.pending_fut.set(None); + let skipped = res?; + let item = this.pending_item.take(); + if !skipped { + *this.done_skipping = true; + break item.map(Ok); + } + } else if let Some(item) = ready!(this.stream.as_mut().try_poll_next(cx)?) { + this.pending_fut.set(Some((this.f)(&item))); + *this.pending_item = Some(item); + } else { + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + let pending_len = usize::from(self.pending_item.is_some()); + let (_, upper) = self.stream.size_hint(); + let upper = match upper { + Some(x) => x.checked_add(pending_len), + None => None, + }; + (0, upper) // can't know a lower bound, due to the predicate + } +} + +impl<St, Fut, F> FusedStream for TrySkipWhile<St, Fut, F> +where + St: TryStream + FusedStream, + F: FnMut(&St::Ok) -> Fut, + Fut: TryFuture<Ok = bool, Error = St::Error>, +{ + fn is_terminated(&self) -> bool { + self.pending_item.is_none() && self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item, E> Sink<Item> for TrySkipWhile<S, Fut, F> +where + S: TryStream + Sink<Item, Error = E>, +{ + type Error = E; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_take_while.rs b/third_party/rust/futures-util/src/stream/try_stream/try_take_while.rs new file mode 100644 index 0000000000..4b5ff1ad38 --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_take_while.rs @@ -0,0 +1,129 @@ +use core::fmt; +use core::pin::Pin; +use futures_core::future::TryFuture; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream, TryStream}; +use futures_core::task::{Context, Poll}; +#[cfg(feature = "sink")] +use futures_sink::Sink; +use pin_project_lite::pin_project; + +pin_project! { + /// Stream for the [`try_take_while`](super::TryStreamExt::try_take_while) + /// method. + #[must_use = "streams do nothing unless polled"] + pub struct TryTakeWhile<St, Fut, F> + where + St: TryStream, + { + #[pin] + stream: St, + f: F, + #[pin] + pending_fut: Option<Fut>, + pending_item: Option<St::Ok>, + done_taking: bool, + } +} + +impl<St, Fut, F> fmt::Debug for TryTakeWhile<St, Fut, F> +where + St: TryStream + fmt::Debug, + St::Ok: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TryTakeWhile") + .field("stream", &self.stream) + .field("pending_fut", &self.pending_fut) + .field("pending_item", &self.pending_item) + .field("done_taking", &self.done_taking) + .finish() + } +} + +impl<St, Fut, F> TryTakeWhile<St, Fut, F> +where + St: TryStream, + F: FnMut(&St::Ok) -> Fut, + Fut: TryFuture<Ok = bool, Error = St::Error>, +{ + pub(super) fn new(stream: St, f: F) -> Self { + Self { stream, f, pending_fut: None, pending_item: None, done_taking: false } + } + + delegate_access_inner!(stream, St, ()); +} + +impl<St, Fut, F> Stream for TryTakeWhile<St, Fut, F> +where + St: TryStream, + F: FnMut(&St::Ok) -> Fut, + Fut: TryFuture<Ok = bool, Error = St::Error>, +{ + type Item = Result<St::Ok, St::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + if *this.done_taking { + return Poll::Ready(None); + } + + Poll::Ready(loop { + if let Some(fut) = this.pending_fut.as_mut().as_pin_mut() { + let res = ready!(fut.try_poll(cx)); + this.pending_fut.set(None); + let take = res?; + let item = this.pending_item.take(); + if take { + break item.map(Ok); + } else { + *this.done_taking = true; + break None; + } + } else if let Some(item) = ready!(this.stream.as_mut().try_poll_next(cx)?) { + this.pending_fut.set(Some((this.f)(&item))); + *this.pending_item = Some(item); + } else { + break None; + } + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + if self.done_taking { + return (0, Some(0)); + } + + let pending_len = usize::from(self.pending_item.is_some()); + let (_, upper) = self.stream.size_hint(); + let upper = match upper { + Some(x) => x.checked_add(pending_len), + None => None, + }; + (0, upper) // can't know a lower bound, due to the predicate + } +} + +impl<St, Fut, F> FusedStream for TryTakeWhile<St, Fut, F> +where + St: TryStream + FusedStream, + F: FnMut(&St::Ok) -> Fut, + Fut: TryFuture<Ok = bool, Error = St::Error>, +{ + fn is_terminated(&self) -> bool { + self.done_taking || self.pending_item.is_none() && self.stream.is_terminated() + } +} + +// Forwarding impl of Sink from the underlying stream +#[cfg(feature = "sink")] +impl<S, Fut, F, Item, E> Sink<Item> for TryTakeWhile<S, Fut, F> +where + S: TryStream + Sink<Item, Error = E>, +{ + type Error = E; + + delegate_sink!(stream, Item); +} diff --git a/third_party/rust/futures-util/src/stream/try_stream/try_unfold.rs b/third_party/rust/futures-util/src/stream/try_stream/try_unfold.rs new file mode 100644 index 0000000000..fd9cdf1d8c --- /dev/null +++ b/third_party/rust/futures-util/src/stream/try_stream/try_unfold.rs @@ -0,0 +1,122 @@ +use super::assert_stream; +use core::fmt; +use core::pin::Pin; +use futures_core::future::TryFuture; +use futures_core::ready; +use futures_core::stream::Stream; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +/// Creates a `TryStream` from a seed and a closure returning a `TryFuture`. +/// +/// This function is the dual for the `TryStream::try_fold()` adapter: while +/// `TryStream::try_fold()` reduces a `TryStream` to one single value, +/// `try_unfold()` creates a `TryStream` from a seed value. +/// +/// `try_unfold()` will call the provided closure with the provided seed, then +/// wait for the returned `TryFuture` to complete with `(a, b)`. It will then +/// yield the value `a`, and use `b` as the next internal state. +/// +/// If the closure returns `None` instead of `Some(TryFuture)`, then the +/// `try_unfold()` will stop producing items and return `Poll::Ready(None)` in +/// future calls to `poll()`. +/// +/// In case of error generated by the returned `TryFuture`, the error will be +/// returned by the `TryStream`. The `TryStream` will then yield +/// `Poll::Ready(None)` in future calls to `poll()`. +/// +/// This function can typically be used when wanting to go from the "world of +/// futures" to the "world of streams": the provided closure can build a +/// `TryFuture` using other library functions working on futures, and +/// `try_unfold()` will turn it into a `TryStream` by repeating the operation. +/// +/// # Example +/// +/// ``` +/// # #[derive(Debug, PartialEq)] +/// # struct SomeError; +/// # futures::executor::block_on(async { +/// use futures::stream::{self, TryStreamExt}; +/// +/// let stream = stream::try_unfold(0, |state| async move { +/// if state < 0 { +/// return Err(SomeError); +/// } +/// +/// if state <= 2 { +/// let next_state = state + 1; +/// let yielded = state * 2; +/// Ok(Some((yielded, next_state))) +/// } else { +/// Ok(None) +/// } +/// }); +/// +/// let result: Result<Vec<i32>, _> = stream.try_collect().await; +/// assert_eq!(result, Ok(vec![0, 2, 4])); +/// # }); +/// ``` +pub fn try_unfold<T, F, Fut, Item>(init: T, f: F) -> TryUnfold<T, F, Fut> +where + F: FnMut(T) -> Fut, + Fut: TryFuture<Ok = Option<(Item, T)>>, +{ + assert_stream::<Result<Item, Fut::Error>, _>(TryUnfold { f, state: Some(init), fut: None }) +} + +pin_project! { + /// Stream for the [`try_unfold`] function. + #[must_use = "streams do nothing unless polled"] + pub struct TryUnfold<T, F, Fut> { + f: F, + state: Option<T>, + #[pin] + fut: Option<Fut>, + } +} + +impl<T, F, Fut> fmt::Debug for TryUnfold<T, F, Fut> +where + T: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("TryUnfold").field("state", &self.state).field("fut", &self.fut).finish() + } +} + +impl<T, F, Fut, Item> Stream for TryUnfold<T, F, Fut> +where + F: FnMut(T) -> Fut, + Fut: TryFuture<Ok = Option<(Item, T)>>, +{ + type Item = Result<Item, Fut::Error>; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + if let Some(state) = this.state.take() { + this.fut.set(Some((this.f)(state))); + } + + match this.fut.as_mut().as_pin_mut() { + None => { + // The future previously errored + Poll::Ready(None) + } + Some(future) => { + let step = ready!(future.try_poll(cx)); + this.fut.set(None); + + match step { + Ok(Some((item, next_state))) => { + *this.state = Some(next_state); + Poll::Ready(Some(Ok(item))) + } + Ok(None) => Poll::Ready(None), + Err(e) => Poll::Ready(Some(Err(e))), + } + } + } + } +} diff --git a/third_party/rust/futures-util/src/stream/unfold.rs b/third_party/rust/futures-util/src/stream/unfold.rs new file mode 100644 index 0000000000..7d8ef6babc --- /dev/null +++ b/third_party/rust/futures-util/src/stream/unfold.rs @@ -0,0 +1,119 @@ +use super::assert_stream; +use crate::unfold_state::UnfoldState; +use core::fmt; +use core::pin::Pin; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::stream::{FusedStream, Stream}; +use futures_core::task::{Context, Poll}; +use pin_project_lite::pin_project; + +/// Creates a `Stream` from a seed and a closure returning a `Future`. +/// +/// This function is the dual for the `Stream::fold()` adapter: while +/// `Stream::fold()` reduces a `Stream` to one single value, `unfold()` creates a +/// `Stream` from a seed value. +/// +/// `unfold()` will call the provided closure with the provided seed, then wait +/// for the returned `Future` to complete with `(a, b)`. It will then yield the +/// value `a`, and use `b` as the next internal state. +/// +/// If the closure returns `None` instead of `Some(Future)`, then the `unfold()` +/// will stop producing items and return `Poll::Ready(None)` in future +/// calls to `poll()`. +/// +/// This function can typically be used when wanting to go from the "world of +/// futures" to the "world of streams": the provided closure can build a +/// `Future` using other library functions working on futures, and `unfold()` +/// will turn it into a `Stream` by repeating the operation. +/// +/// # Example +/// +/// ``` +/// # futures::executor::block_on(async { +/// use futures::stream::{self, StreamExt}; +/// +/// let stream = stream::unfold(0, |state| async move { +/// if state <= 2 { +/// let next_state = state + 1; +/// let yielded = state * 2; +/// Some((yielded, next_state)) +/// } else { +/// None +/// } +/// }); +/// +/// let result = stream.collect::<Vec<i32>>().await; +/// assert_eq!(result, vec![0, 2, 4]); +/// # }); +/// ``` +pub fn unfold<T, F, Fut, Item>(init: T, f: F) -> Unfold<T, F, Fut> +where + F: FnMut(T) -> Fut, + Fut: Future<Output = Option<(Item, T)>>, +{ + assert_stream::<Item, _>(Unfold { f, state: UnfoldState::Value { value: init } }) +} + +pin_project! { + /// Stream for the [`unfold`] function. + #[must_use = "streams do nothing unless polled"] + pub struct Unfold<T, F, Fut> { + f: F, + #[pin] + state: UnfoldState<T, Fut>, + } +} + +impl<T, F, Fut> fmt::Debug for Unfold<T, F, Fut> +where + T: fmt::Debug, + Fut: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Unfold").field("state", &self.state).finish() + } +} + +impl<T, F, Fut, Item> FusedStream for Unfold<T, F, Fut> +where + F: FnMut(T) -> Fut, + Fut: Future<Output = Option<(Item, T)>>, +{ + fn is_terminated(&self) -> bool { + if let UnfoldState::Empty = self.state { + true + } else { + false + } + } +} + +impl<T, F, Fut, Item> Stream for Unfold<T, F, Fut> +where + F: FnMut(T) -> Fut, + Fut: Future<Output = Option<(Item, T)>>, +{ + type Item = Item; + + fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { + let mut this = self.project(); + + if let Some(state) = this.state.as_mut().take_value() { + this.state.set(UnfoldState::Future { future: (this.f)(state) }); + } + + let step = match this.state.as_mut().project_future() { + Some(fut) => ready!(fut.poll(cx)), + None => panic!("Unfold must not be polled after it returned `Poll::Ready(None)`"), + }; + + if let Some((item, next_state)) = step { + this.state.set(UnfoldState::Value { value: next_state }); + Poll::Ready(Some(item)) + } else { + this.state.set(UnfoldState::Empty); + Poll::Ready(None) + } + } +} diff --git a/third_party/rust/futures-util/src/task/mod.rs b/third_party/rust/futures-util/src/task/mod.rs new file mode 100644 index 0000000000..0a31eeac14 --- /dev/null +++ b/third_party/rust/futures-util/src/task/mod.rs @@ -0,0 +1,37 @@ +//! Tools for working with tasks. +//! +//! This module contains: +//! +//! - [`Spawn`], a trait for spawning new tasks. +//! - [`Context`], a context of an asynchronous task, +//! including a handle for waking up the task. +//! - [`Waker`], a handle for waking up a task. +//! +//! The remaining types and traits in the module are used for implementing +//! executors or dealing with synchronization issues around task wakeup. + +#[doc(no_inline)] +pub use core::task::{Context, Poll, RawWaker, RawWakerVTable, Waker}; + +pub use futures_task::{FutureObj, LocalFutureObj, LocalSpawn, Spawn, SpawnError, UnsafeFutureObj}; + +pub use futures_task::noop_waker; +pub use futures_task::noop_waker_ref; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use futures_task::ArcWake; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use futures_task::waker; + +#[cfg(not(futures_no_atomic_cas))] +#[cfg(feature = "alloc")] +pub use futures_task::{waker_ref, WakerRef}; + +#[cfg(not(futures_no_atomic_cas))] +pub use futures_core::task::__internal::AtomicWaker; + +mod spawn; +pub use self::spawn::{LocalSpawnExt, SpawnExt}; diff --git a/third_party/rust/futures-util/src/task/spawn.rs b/third_party/rust/futures-util/src/task/spawn.rs new file mode 100644 index 0000000000..d9e9985309 --- /dev/null +++ b/third_party/rust/futures-util/src/task/spawn.rs @@ -0,0 +1,169 @@ +use futures_task::{LocalSpawn, Spawn}; + +#[cfg(feature = "compat")] +use crate::compat::Compat; + +#[cfg(feature = "channel")] +#[cfg(feature = "std")] +use crate::future::{FutureExt, RemoteHandle}; +#[cfg(feature = "alloc")] +use alloc::boxed::Box; +#[cfg(feature = "alloc")] +use futures_core::future::Future; +#[cfg(feature = "alloc")] +use futures_task::{FutureObj, LocalFutureObj, SpawnError}; + +impl<Sp: ?Sized> SpawnExt for Sp where Sp: Spawn {} +impl<Sp: ?Sized> LocalSpawnExt for Sp where Sp: LocalSpawn {} + +/// Extension trait for `Spawn`. +pub trait SpawnExt: Spawn { + /// Spawns a task that polls the given future with output `()` to + /// completion. + /// + /// This method returns a [`Result`] that contains a [`SpawnError`] if + /// spawning fails. + /// + /// You can use [`spawn_with_handle`](SpawnExt::spawn_with_handle) if + /// you want to spawn a future with output other than `()` or if you want + /// to be able to await its completion. + /// + /// Note this method will eventually be replaced with the upcoming + /// `Spawn::spawn` method which will take a `dyn Future` as input. + /// Technical limitations prevent `Spawn::spawn` from being implemented + /// today. Feel free to use this method in the meantime. + /// + /// ``` + /// # { + /// use futures::executor::ThreadPool; + /// use futures::task::SpawnExt; + /// + /// let executor = ThreadPool::new().unwrap(); + /// + /// let future = async { /* ... */ }; + /// executor.spawn(future).unwrap(); + /// # } + /// # std::thread::sleep(std::time::Duration::from_millis(500)); // wait for background threads closed: https://github.com/rust-lang/miri/issues/1371 + /// ``` + #[cfg(feature = "alloc")] + fn spawn<Fut>(&self, future: Fut) -> Result<(), SpawnError> + where + Fut: Future<Output = ()> + Send + 'static, + { + self.spawn_obj(FutureObj::new(Box::new(future))) + } + + /// Spawns a task that polls the given future to completion and returns a + /// future that resolves to the spawned future's output. + /// + /// This method returns a [`Result`] that contains a [`RemoteHandle`](crate::future::RemoteHandle), or, if + /// spawning fails, a [`SpawnError`]. [`RemoteHandle`](crate::future::RemoteHandle) is a future that + /// resolves to the output of the spawned future. + /// + /// ``` + /// # { + /// use futures::executor::{block_on, ThreadPool}; + /// use futures::future; + /// use futures::task::SpawnExt; + /// + /// let executor = ThreadPool::new().unwrap(); + /// + /// let future = future::ready(1); + /// let join_handle_fut = executor.spawn_with_handle(future).unwrap(); + /// assert_eq!(block_on(join_handle_fut), 1); + /// # } + /// # std::thread::sleep(std::time::Duration::from_millis(500)); // wait for background threads closed: https://github.com/rust-lang/miri/issues/1371 + /// ``` + #[cfg(feature = "channel")] + #[cfg_attr(docsrs, doc(cfg(feature = "channel")))] + #[cfg(feature = "std")] + fn spawn_with_handle<Fut>(&self, future: Fut) -> Result<RemoteHandle<Fut::Output>, SpawnError> + where + Fut: Future + Send + 'static, + Fut::Output: Send, + { + let (future, handle) = future.remote_handle(); + self.spawn(future)?; + Ok(handle) + } + + /// Wraps a [`Spawn`] and makes it usable as a futures 0.1 `Executor`. + /// Requires the `compat` feature to enable. + #[cfg(feature = "compat")] + #[cfg_attr(docsrs, doc(cfg(feature = "compat")))] + fn compat(self) -> Compat<Self> + where + Self: Sized, + { + Compat::new(self) + } +} + +/// Extension trait for `LocalSpawn`. +pub trait LocalSpawnExt: LocalSpawn { + /// Spawns a task that polls the given future with output `()` to + /// completion. + /// + /// This method returns a [`Result`] that contains a [`SpawnError`] if + /// spawning fails. + /// + /// You can use [`spawn_with_handle`](SpawnExt::spawn_with_handle) if + /// you want to spawn a future with output other than `()` or if you want + /// to be able to await its completion. + /// + /// Note this method will eventually be replaced with the upcoming + /// `Spawn::spawn` method which will take a `dyn Future` as input. + /// Technical limitations prevent `Spawn::spawn` from being implemented + /// today. Feel free to use this method in the meantime. + /// + /// ``` + /// use futures::executor::LocalPool; + /// use futures::task::LocalSpawnExt; + /// + /// let executor = LocalPool::new(); + /// let spawner = executor.spawner(); + /// + /// let future = async { /* ... */ }; + /// spawner.spawn_local(future).unwrap(); + /// ``` + #[cfg(feature = "alloc")] + fn spawn_local<Fut>(&self, future: Fut) -> Result<(), SpawnError> + where + Fut: Future<Output = ()> + 'static, + { + self.spawn_local_obj(LocalFutureObj::new(Box::new(future))) + } + + /// Spawns a task that polls the given future to completion and returns a + /// future that resolves to the spawned future's output. + /// + /// This method returns a [`Result`] that contains a [`RemoteHandle`](crate::future::RemoteHandle), or, if + /// spawning fails, a [`SpawnError`]. [`RemoteHandle`](crate::future::RemoteHandle) is a future that + /// resolves to the output of the spawned future. + /// + /// ``` + /// use futures::executor::LocalPool; + /// use futures::task::LocalSpawnExt; + /// + /// let mut executor = LocalPool::new(); + /// let spawner = executor.spawner(); + /// + /// let future = async { 1 }; + /// let join_handle_fut = spawner.spawn_local_with_handle(future).unwrap(); + /// assert_eq!(executor.run_until(join_handle_fut), 1); + /// ``` + #[cfg(feature = "channel")] + #[cfg_attr(docsrs, doc(cfg(feature = "channel")))] + #[cfg(feature = "std")] + fn spawn_local_with_handle<Fut>( + &self, + future: Fut, + ) -> Result<RemoteHandle<Fut::Output>, SpawnError> + where + Fut: Future + 'static, + { + let (future, handle) = future.remote_handle(); + self.spawn_local(future)?; + Ok(handle) + } +} diff --git a/third_party/rust/futures-util/src/unfold_state.rs b/third_party/rust/futures-util/src/unfold_state.rs new file mode 100644 index 0000000000..0edc15e437 --- /dev/null +++ b/third_party/rust/futures-util/src/unfold_state.rs @@ -0,0 +1,39 @@ +use core::pin::Pin; + +use pin_project_lite::pin_project; + +pin_project! { + /// UnfoldState used for stream and sink unfolds + #[project = UnfoldStateProj] + #[project_replace = UnfoldStateProjReplace] + #[derive(Debug)] + pub(crate) enum UnfoldState<T, R> { + Value { + value: T, + }, + Future { + #[pin] + future: R, + }, + Empty, + } +} + +impl<T, R> UnfoldState<T, R> { + pub(crate) fn project_future(self: Pin<&mut Self>) -> Option<Pin<&mut R>> { + match self.project() { + UnfoldStateProj::Future { future } => Some(future), + _ => None, + } + } + + pub(crate) fn take_value(self: Pin<&mut Self>) -> Option<T> { + match &*self { + UnfoldState::Value { .. } => match self.project_replace(UnfoldState::Empty) { + UnfoldStateProjReplace::Value { value } => Some(value), + _ => unreachable!(), + }, + _ => None, + } + } +} |