1 files changed, 112 insertions, 0 deletions
diff --git a/vendor/futures-util/src/stream/try_stream/try_filter.rs b/vendor/futures-util/src/stream/try_stream/try_filter.rs
new file mode 100644
index 000000000..61e6105c3
--- /dev/null
+++ b/vendor/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 = if self.pending_fut.is_some() { 1 } else { 0 };
+        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);
+}