1 files changed, 62 insertions, 0 deletions
diff --git a/vendor/futures-util/src/future/try_future/try_flatten_err.rs b/vendor/futures-util/src/future/try_future/try_flatten_err.rs
new file mode 100644
index 000000000..39b7d9f5f
--- /dev/null
+++ b/vendor/futures-util/src/future/try_future/try_flatten_err.rs
@@ -0,0 +1,62 @@
+use core::pin::Pin;
+use futures_core::future::{FusedFuture, Future, TryFuture};
+use futures_core::ready;
+use futures_core::task::{Context, Poll};
+use pin_project_lite::pin_project;
+
+pin_project! {
+    #[project = TryFlattenErrProj]
+    #[derive(Debug)]
+    pub enum TryFlattenErr<Fut1, Fut2> {
+        First { #[pin] f: Fut1 },
+        Second { #[pin] f: Fut2 },
+        Empty,
+    }
+}
+
+impl<Fut1, Fut2> TryFlattenErr<Fut1, Fut2> {
+    pub(crate) fn new(future: Fut1) -> Self {
+        Self::First { f: future }
+    }
+}
+
+impl<Fut> FusedFuture for TryFlattenErr<Fut, Fut::Error>
+where
+    Fut: TryFuture,
+    Fut::Error: TryFuture<Ok = Fut::Ok>,
+{
+    fn is_terminated(&self) -> bool {
+        match self {
+            Self::Empty => true,
+            _ => false,
+        }
+    }
+}
+
+impl<Fut> Future for TryFlattenErr<Fut, Fut::Error>
+where
+    Fut: TryFuture,
+    Fut::Error: TryFuture<Ok = Fut::Ok>,
+{
+    type Output = Result<Fut::Ok, <Fut::Error as TryFuture>::Error>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        Poll::Ready(loop {
+            match self.as_mut().project() {
+                TryFlattenErrProj::First { f } => match ready!(f.try_poll(cx)) {
+                    Err(f) => self.set(Self::Second { f }),
+                    Ok(e) => {
+                        self.set(Self::Empty);
+                        break Ok(e);
+                    }
+                },
+                TryFlattenErrProj::Second { f } => {
+                    let output = ready!(f.try_poll(cx));
+                    self.set(Self::Empty);
+                    break output;
+                }
+                TryFlattenErrProj::Empty => panic!("TryFlattenErr polled after completion"),
+            }
+        })
+    }
+}