1 files changed, 111 insertions, 0 deletions
diff --git a/vendor/futures-util/src/stream/stream/filter_map.rs b/vendor/futures-util/src/stream/stream/filter_map.rs
new file mode 100644
index 000000000..02a0a4386
--- /dev/null
+++ b/vendor/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 = if self.pending.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> 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);
+}