Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 317 insertions, 0 deletions

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),
+            }
+        }
+    }
+}