Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

1 files changed, 254 insertions, 0 deletions

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> {}