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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
commit698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch)
tree173a775858bd501c378080a10dca74132f05bc50 /vendor/futures-io/src/lib.rs
parentInitial commit. (diff)
downloadrustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz
rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/futures-io/src/lib.rs')
-rw-r--r--vendor/futures-io/src/lib.rs558
1 files changed, 558 insertions, 0 deletions
diff --git a/vendor/futures-io/src/lib.rs b/vendor/futures-io/src/lib.rs
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+//! Asynchronous I/O
+//!
+//! This crate contains the `AsyncRead`, `AsyncWrite`, `AsyncSeek`, and
+//! `AsyncBufRead` traits, the asynchronous analogs to
+//! `std::io::{Read, Write, Seek, BufRead}`. The primary difference is
+//! that these traits integrate with the asynchronous task system.
+//!
+//! All items of this library are only available when the `std` feature of this
+//! library is activated, and it is activated by default.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+#![warn(missing_debug_implementations, missing_docs, rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, warn(single_use_lifetimes))]
+#![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(feature = "std")]
+mod if_std {
+ use std::io;
+ use std::ops::DerefMut;
+ use std::pin::Pin;
+ use std::task::{Context, Poll};
+
+ // 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`.
+ #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
+ #[doc(no_inline)]
+ pub use io::{Error, ErrorKind, IoSlice, IoSliceMut, Result, SeekFrom};
+
+ /// Read bytes asynchronously.
+ ///
+ /// This trait is analogous to the `std::io::Read` trait, but integrates
+ /// with the asynchronous task system. In particular, the `poll_read`
+ /// method, unlike `Read::read`, will automatically queue the current task
+ /// for wakeup and return if data is not yet available, rather than blocking
+ /// the calling thread.
+ pub trait AsyncRead {
+ /// Attempt to read from the `AsyncRead` into `buf`.
+ ///
+ /// On success, returns `Poll::Ready(Ok(num_bytes_read))`.
+ ///
+ /// If no data is available for reading, the method returns
+ /// `Poll::Pending` and arranges for the current task (via
+ /// `cx.waker().wake_by_ref()`) to receive a notification when the object becomes
+ /// readable or is closed.
+ ///
+ /// # Implementation
+ ///
+ /// This function may not return errors of kind `WouldBlock` or
+ /// `Interrupted`. Implementations must convert `WouldBlock` into
+ /// `Poll::Pending` and either internally retry or convert
+ /// `Interrupted` into another error kind.
+ fn poll_read(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ buf: &mut [u8],
+ ) -> Poll<Result<usize>>;
+
+ /// Attempt to read from the `AsyncRead` into `bufs` using vectored
+ /// IO operations.
+ ///
+ /// This method is similar to `poll_read`, but allows data to be read
+ /// into multiple buffers using a single operation.
+ ///
+ /// On success, returns `Poll::Ready(Ok(num_bytes_read))`.
+ ///
+ /// If no data is available for reading, the method returns
+ /// `Poll::Pending` and arranges for the current task (via
+ /// `cx.waker().wake_by_ref()`) to receive a notification when the object becomes
+ /// readable or is closed.
+ /// By default, this method delegates to using `poll_read` on the first
+ /// nonempty buffer in `bufs`, or an empty one if none exists. Objects which
+ /// support vectored IO should override this method.
+ ///
+ /// # Implementation
+ ///
+ /// This function may not return errors of kind `WouldBlock` or
+ /// `Interrupted`. Implementations must convert `WouldBlock` into
+ /// `Poll::Pending` and either internally retry or convert
+ /// `Interrupted` into another error kind.
+ fn poll_read_vectored(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ bufs: &mut [IoSliceMut<'_>],
+ ) -> Poll<Result<usize>> {
+ for b in bufs {
+ if !b.is_empty() {
+ return self.poll_read(cx, b);
+ }
+ }
+
+ self.poll_read(cx, &mut [])
+ }
+ }
+
+ /// Write bytes asynchronously.
+ ///
+ /// This trait is analogous to the `std::io::Write` trait, but integrates
+ /// with the asynchronous task system. In particular, the `poll_write`
+ /// method, unlike `Write::write`, will automatically queue the current task
+ /// for wakeup and return if the writer cannot take more data, rather than blocking
+ /// the calling thread.
+ pub trait AsyncWrite {
+ /// Attempt to write bytes from `buf` into the object.
+ ///
+ /// On success, returns `Poll::Ready(Ok(num_bytes_written))`.
+ ///
+ /// If the object is not ready for writing, the method returns
+ /// `Poll::Pending` and arranges for the current task (via
+ /// `cx.waker().wake_by_ref()`) to receive a notification when the object becomes
+ /// writable or is closed.
+ ///
+ /// # Implementation
+ ///
+ /// This function may not return errors of kind `WouldBlock` or
+ /// `Interrupted`. Implementations must convert `WouldBlock` into
+ /// `Poll::Pending` and either internally retry or convert
+ /// `Interrupted` into another error kind.
+ ///
+ /// `poll_write` must try to make progress by flushing the underlying object if
+ /// that is the only way the underlying object can become writable again.
+ fn poll_write(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ buf: &[u8],
+ ) -> Poll<Result<usize>>;
+
+ /// Attempt to write bytes from `bufs` into the object using vectored
+ /// IO operations.
+ ///
+ /// This method is similar to `poll_write`, but allows data from multiple buffers to be written
+ /// using a single operation.
+ ///
+ /// On success, returns `Poll::Ready(Ok(num_bytes_written))`.
+ ///
+ /// If the object is not ready for writing, the method returns
+ /// `Poll::Pending` and arranges for the current task (via
+ /// `cx.waker().wake_by_ref()`) to receive a notification when the object becomes
+ /// writable or is closed.
+ ///
+ /// By default, this method delegates to using `poll_write` on the first
+ /// nonempty buffer in `bufs`, or an empty one if none exists. Objects which
+ /// support vectored IO should override this method.
+ ///
+ /// # Implementation
+ ///
+ /// This function may not return errors of kind `WouldBlock` or
+ /// `Interrupted`. Implementations must convert `WouldBlock` into
+ /// `Poll::Pending` and either internally retry or convert
+ /// `Interrupted` into another error kind.
+ fn poll_write_vectored(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ bufs: &[IoSlice<'_>],
+ ) -> Poll<Result<usize>> {
+ for b in bufs {
+ if !b.is_empty() {
+ return self.poll_write(cx, b);
+ }
+ }
+
+ self.poll_write(cx, &[])
+ }
+
+ /// Attempt to flush the object, ensuring that any buffered data reach
+ /// their destination.
+ ///
+ /// On success, returns `Poll::Ready(Ok(()))`.
+ ///
+ /// If flushing cannot immediately complete, this method returns
+ /// `Poll::Pending` and arranges for the current task (via
+ /// `cx.waker().wake_by_ref()`) to receive a notification when the object can make
+ /// progress towards flushing.
+ ///
+ /// # Implementation
+ ///
+ /// This function may not return errors of kind `WouldBlock` or
+ /// `Interrupted`. Implementations must convert `WouldBlock` into
+ /// `Poll::Pending` and either internally retry or convert
+ /// `Interrupted` into another error kind.
+ ///
+ /// It only makes sense to do anything here if you actually buffer data.
+ fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>;
+
+ /// Attempt to close the object.
+ ///
+ /// On success, returns `Poll::Ready(Ok(()))`.
+ ///
+ /// If closing cannot immediately complete, this function returns
+ /// `Poll::Pending` and arranges for the current task (via
+ /// `cx.waker().wake_by_ref()`) to receive a notification when the object can make
+ /// progress towards closing.
+ ///
+ /// # Implementation
+ ///
+ /// This function may not return errors of kind `WouldBlock` or
+ /// `Interrupted`. Implementations must convert `WouldBlock` into
+ /// `Poll::Pending` and either internally retry or convert
+ /// `Interrupted` into another error kind.
+ fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>;
+ }
+
+ /// Seek bytes asynchronously.
+ ///
+ /// This trait is analogous to the `std::io::Seek` trait, but integrates
+ /// with the asynchronous task system. In particular, the `poll_seek`
+ /// method, unlike `Seek::seek`, will automatically queue the current task
+ /// for wakeup and return if data is not yet available, rather than blocking
+ /// the calling thread.
+ pub trait AsyncSeek {
+ /// Attempt to seek to an offset, in bytes, in a stream.
+ ///
+ /// A seek beyond the end of a stream is allowed, but behavior is defined
+ /// by the implementation.
+ ///
+ /// If the seek operation completed successfully,
+ /// this method returns the new position from the start of the stream.
+ /// That position can be used later with [`SeekFrom::Start`].
+ ///
+ /// # Errors
+ ///
+ /// Seeking to a negative offset is considered an error.
+ ///
+ /// # Implementation
+ ///
+ /// This function may not return errors of kind `WouldBlock` or
+ /// `Interrupted`. Implementations must convert `WouldBlock` into
+ /// `Poll::Pending` and either internally retry or convert
+ /// `Interrupted` into another error kind.
+ fn poll_seek(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ pos: SeekFrom,
+ ) -> Poll<Result<u64>>;
+ }
+
+ /// Read bytes asynchronously.
+ ///
+ /// This trait is analogous to the `std::io::BufRead` trait, but integrates
+ /// with the asynchronous task system. In particular, the `poll_fill_buf`
+ /// method, unlike `BufRead::fill_buf`, will automatically queue the current task
+ /// for wakeup and return if data is not yet available, rather than blocking
+ /// the calling thread.
+ pub trait AsyncBufRead: AsyncRead {
+ /// Attempt to return the contents of the internal buffer, filling it with more data
+ /// from the inner reader if it is empty.
+ ///
+ /// On success, returns `Poll::Ready(Ok(buf))`.
+ ///
+ /// If no data is available for reading, the method returns
+ /// `Poll::Pending` and arranges for the current task (via
+ /// `cx.waker().wake_by_ref()`) to receive a notification when the object becomes
+ /// readable or is closed.
+ ///
+ /// This function is a lower-level call. It needs to be paired with the
+ /// [`consume`] method to function properly. When calling this
+ /// method, none of the contents will be "read" in the sense that later
+ /// calling [`poll_read`] may return the same contents. As such, [`consume`] must
+ /// be called with the number of bytes that are consumed from this buffer to
+ /// ensure that the bytes are never returned twice.
+ ///
+ /// [`poll_read`]: AsyncRead::poll_read
+ /// [`consume`]: AsyncBufRead::consume
+ ///
+ /// An empty buffer returned indicates that the stream has reached EOF.
+ ///
+ /// # Implementation
+ ///
+ /// This function may not return errors of kind `WouldBlock` or
+ /// `Interrupted`. Implementations must convert `WouldBlock` into
+ /// `Poll::Pending` and either internally retry or convert
+ /// `Interrupted` into another error kind.
+ fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<&[u8]>>;
+
+ /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+ /// so they should no longer be returned in calls to [`poll_read`].
+ ///
+ /// This function is a lower-level call. It needs to be paired with the
+ /// [`poll_fill_buf`] method to function properly. This function does
+ /// not perform any I/O, it simply informs this object that some amount of
+ /// its buffer, returned from [`poll_fill_buf`], has been consumed and should
+ /// no longer be returned. As such, this function may do odd things if
+ /// [`poll_fill_buf`] isn't called before calling it.
+ ///
+ /// The `amt` must be `<=` the number of bytes in the buffer returned by
+ /// [`poll_fill_buf`].
+ ///
+ /// [`poll_read`]: AsyncRead::poll_read
+ /// [`poll_fill_buf`]: AsyncBufRead::poll_fill_buf
+ fn consume(self: Pin<&mut Self>, amt: usize);
+ }
+
+ macro_rules! deref_async_read {
+ () => {
+ fn poll_read(
+ mut self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ buf: &mut [u8],
+ ) -> Poll<Result<usize>> {
+ Pin::new(&mut **self).poll_read(cx, buf)
+ }
+
+ fn poll_read_vectored(
+ mut self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ bufs: &mut [IoSliceMut<'_>],
+ ) -> Poll<Result<usize>> {
+ Pin::new(&mut **self).poll_read_vectored(cx, bufs)
+ }
+ };
+ }
+
+ impl<T: ?Sized + AsyncRead + Unpin> AsyncRead for Box<T> {
+ deref_async_read!();
+ }
+
+ impl<T: ?Sized + AsyncRead + Unpin> AsyncRead for &mut T {
+ deref_async_read!();
+ }
+
+ impl<P> AsyncRead for Pin<P>
+ where
+ P: DerefMut + Unpin,
+ P::Target: AsyncRead,
+ {
+ fn poll_read(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ buf: &mut [u8],
+ ) -> Poll<Result<usize>> {
+ self.get_mut().as_mut().poll_read(cx, buf)
+ }
+
+ fn poll_read_vectored(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ bufs: &mut [IoSliceMut<'_>],
+ ) -> Poll<Result<usize>> {
+ self.get_mut().as_mut().poll_read_vectored(cx, bufs)
+ }
+ }
+
+ macro_rules! delegate_async_read_to_stdio {
+ () => {
+ fn poll_read(
+ mut self: Pin<&mut Self>,
+ _: &mut Context<'_>,
+ buf: &mut [u8],
+ ) -> Poll<Result<usize>> {
+ Poll::Ready(io::Read::read(&mut *self, buf))
+ }
+
+ fn poll_read_vectored(
+ mut self: Pin<&mut Self>,
+ _: &mut Context<'_>,
+ bufs: &mut [IoSliceMut<'_>],
+ ) -> Poll<Result<usize>> {
+ Poll::Ready(io::Read::read_vectored(&mut *self, bufs))
+ }
+ };
+ }
+
+ impl AsyncRead for &[u8] {
+ delegate_async_read_to_stdio!();
+ }
+
+ macro_rules! deref_async_write {
+ () => {
+ fn poll_write(
+ mut self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ buf: &[u8],
+ ) -> Poll<Result<usize>> {
+ Pin::new(&mut **self).poll_write(cx, buf)
+ }
+
+ fn poll_write_vectored(
+ mut self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ bufs: &[IoSlice<'_>],
+ ) -> Poll<Result<usize>> {
+ Pin::new(&mut **self).poll_write_vectored(cx, bufs)
+ }
+
+ fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
+ Pin::new(&mut **self).poll_flush(cx)
+ }
+
+ fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
+ Pin::new(&mut **self).poll_close(cx)
+ }
+ };
+ }
+
+ impl<T: ?Sized + AsyncWrite + Unpin> AsyncWrite for Box<T> {
+ deref_async_write!();
+ }
+
+ impl<T: ?Sized + AsyncWrite + Unpin> AsyncWrite for &mut T {
+ deref_async_write!();
+ }
+
+ impl<P> AsyncWrite for Pin<P>
+ where
+ P: DerefMut + Unpin,
+ P::Target: AsyncWrite,
+ {
+ fn poll_write(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ buf: &[u8],
+ ) -> Poll<Result<usize>> {
+ self.get_mut().as_mut().poll_write(cx, buf)
+ }
+
+ fn poll_write_vectored(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ bufs: &[IoSlice<'_>],
+ ) -> Poll<Result<usize>> {
+ self.get_mut().as_mut().poll_write_vectored(cx, bufs)
+ }
+
+ fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
+ self.get_mut().as_mut().poll_flush(cx)
+ }
+
+ fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
+ self.get_mut().as_mut().poll_close(cx)
+ }
+ }
+
+ macro_rules! delegate_async_write_to_stdio {
+ () => {
+ fn poll_write(
+ mut self: Pin<&mut Self>,
+ _: &mut Context<'_>,
+ buf: &[u8],
+ ) -> Poll<Result<usize>> {
+ Poll::Ready(io::Write::write(&mut *self, buf))
+ }
+
+ fn poll_write_vectored(
+ mut self: Pin<&mut Self>,
+ _: &mut Context<'_>,
+ bufs: &[IoSlice<'_>],
+ ) -> Poll<Result<usize>> {
+ Poll::Ready(io::Write::write_vectored(&mut *self, bufs))
+ }
+
+ fn poll_flush(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<()>> {
+ Poll::Ready(io::Write::flush(&mut *self))
+ }
+
+ fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
+ self.poll_flush(cx)
+ }
+ };
+ }
+
+ impl AsyncWrite for Vec<u8> {
+ delegate_async_write_to_stdio!();
+ }
+
+ macro_rules! deref_async_seek {
+ () => {
+ fn poll_seek(
+ mut self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ pos: SeekFrom,
+ ) -> Poll<Result<u64>> {
+ Pin::new(&mut **self).poll_seek(cx, pos)
+ }
+ };
+ }
+
+ impl<T: ?Sized + AsyncSeek + Unpin> AsyncSeek for Box<T> {
+ deref_async_seek!();
+ }
+
+ impl<T: ?Sized + AsyncSeek + Unpin> AsyncSeek for &mut T {
+ deref_async_seek!();
+ }
+
+ impl<P> AsyncSeek for Pin<P>
+ where
+ P: DerefMut + Unpin,
+ P::Target: AsyncSeek,
+ {
+ fn poll_seek(
+ self: Pin<&mut Self>,
+ cx: &mut Context<'_>,
+ pos: SeekFrom,
+ ) -> Poll<Result<u64>> {
+ self.get_mut().as_mut().poll_seek(cx, pos)
+ }
+ }
+
+ macro_rules! deref_async_buf_read {
+ () => {
+ fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<&[u8]>> {
+ Pin::new(&mut **self.get_mut()).poll_fill_buf(cx)
+ }
+
+ fn consume(mut self: Pin<&mut Self>, amt: usize) {
+ Pin::new(&mut **self).consume(amt)
+ }
+ };
+ }
+
+ impl<T: ?Sized + AsyncBufRead + Unpin> AsyncBufRead for Box<T> {
+ deref_async_buf_read!();
+ }
+
+ impl<T: ?Sized + AsyncBufRead + Unpin> AsyncBufRead for &mut T {
+ deref_async_buf_read!();
+ }
+
+ impl<P> AsyncBufRead for Pin<P>
+ where
+ P: DerefMut + Unpin,
+ P::Target: AsyncBufRead,
+ {
+ fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<&[u8]>> {
+ self.get_mut().as_mut().poll_fill_buf(cx)
+ }
+
+ fn consume(self: Pin<&mut Self>, amt: usize) {
+ self.get_mut().as_mut().consume(amt)
+ }
+ }
+
+ macro_rules! delegate_async_buf_read_to_stdio {
+ () => {
+ fn poll_fill_buf(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<&[u8]>> {
+ Poll::Ready(io::BufRead::fill_buf(self.get_mut()))
+ }
+
+ fn consume(self: Pin<&mut Self>, amt: usize) {
+ io::BufRead::consume(self.get_mut(), amt)
+ }
+ };
+ }
+
+ impl AsyncBufRead for &[u8] {
+ delegate_async_buf_read_to_stdio!();
+ }
+}
+
+#[cfg(feature = "std")]
+pub use self::if_std::*;