1 files changed, 365 insertions, 0 deletions
diff --git a/third_party/rust/hyper/src/upgrade.rs b/third_party/rust/hyper/src/upgrade.rs
new file mode 100644
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+++ b/third_party/rust/hyper/src/upgrade.rs
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+//! HTTP Upgrades
+//!
+//! See [this example][example] showing how upgrades work with both
+//! Clients and Servers.
+//!
+//! [example]: https://github.com/hyperium/hyper/blob/master/examples/upgrades.rs
+
+use std::any::TypeId;
+use std::error::Error as StdError;
+use std::fmt;
+use std::io;
+use std::marker::Unpin;
+
+use bytes::{Buf, Bytes};
+use tokio::io::{AsyncRead, AsyncWrite};
+use tokio::sync::oneshot;
+
+use crate::common::io::Rewind;
+use crate::common::{task, Future, Pin, Poll};
+
+/// An upgraded HTTP connection.
+///
+/// This type holds a trait object internally of the original IO that
+/// was used to speak HTTP before the upgrade. It can be used directly
+/// as a `Read` or `Write` for convenience.
+///
+/// Alternatively, if the exact type is known, this can be deconstructed
+/// into its parts.
+pub struct Upgraded {
+    io: Rewind<Box<dyn Io + Send>>,
+}
+
+/// A future for a possible HTTP upgrade.
+///
+/// If no upgrade was available, or it doesn't succeed, yields an `Error`.
+pub struct OnUpgrade {
+    rx: Option<oneshot::Receiver<crate::Result<Upgraded>>>,
+}
+
+/// The deconstructed parts of an [`Upgraded`](Upgraded) type.
+///
+/// Includes the original IO type, and a read buffer of bytes that the
+/// HTTP state machine may have already read before completing an upgrade.
+#[derive(Debug)]
+pub struct Parts<T> {
+    /// The original IO object used before the upgrade.
+    pub io: T,
+    /// A buffer of bytes that have been read but not processed as HTTP.
+    ///
+    /// For instance, if the `Connection` is used for an HTTP upgrade request,
+    /// it is possible the server sent back the first bytes of the new protocol
+    /// along with the response upgrade.
+    ///
+    /// You will want to check for any existing bytes if you plan to continue
+    /// communicating on the IO object.
+    pub read_buf: Bytes,
+    _inner: (),
+}
+
+pub(crate) struct Pending {
+    tx: oneshot::Sender<crate::Result<Upgraded>>,
+}
+
+/// Error cause returned when an upgrade was expected but canceled
+/// for whatever reason.
+///
+/// This likely means the actual `Conn` future wasn't polled and upgraded.
+#[derive(Debug)]
+struct UpgradeExpected(());
+
+pub(crate) fn pending() -> (Pending, OnUpgrade) {
+    let (tx, rx) = oneshot::channel();
+    (Pending { tx }, OnUpgrade { rx: Some(rx) })
+}
+
+// ===== impl Upgraded =====
+
+impl Upgraded {
+    pub(crate) fn new<T>(io: T, read_buf: Bytes) -> Self
+    where
+        T: AsyncRead + AsyncWrite + Unpin + Send + 'static,
+    {
+        Upgraded {
+            io: Rewind::new_buffered(Box::new(ForwardsWriteBuf(io)), read_buf),
+        }
+    }
+
+    /// Tries to downcast the internal trait object to the type passed.
+    ///
+    /// On success, returns the downcasted parts. On error, returns the
+    /// `Upgraded` back.
+    pub fn downcast<T: AsyncRead + AsyncWrite + Unpin + 'static>(self) -> Result<Parts<T>, Self> {
+        let (io, buf) = self.io.into_inner();
+        match io.__hyper_downcast::<ForwardsWriteBuf<T>>() {
+            Ok(t) => Ok(Parts {
+                io: t.0,
+                read_buf: buf,
+                _inner: (),
+            }),
+            Err(io) => Err(Upgraded {
+                io: Rewind::new_buffered(io, buf),
+            }),
+        }
+    }
+}
+
+impl AsyncRead for Upgraded {
+    unsafe fn prepare_uninitialized_buffer(&self, buf: &mut [std::mem::MaybeUninit<u8>]) -> bool {
+        self.io.prepare_uninitialized_buffer(buf)
+    }
+
+    fn poll_read(
+        mut self: Pin<&mut Self>,
+        cx: &mut task::Context<'_>,
+        buf: &mut [u8],
+    ) -> Poll<io::Result<usize>> {
+        Pin::new(&mut self.io).poll_read(cx, buf)
+    }
+}
+
+impl AsyncWrite for Upgraded {
+    fn poll_write(
+        mut self: Pin<&mut Self>,
+        cx: &mut task::Context<'_>,
+        buf: &[u8],
+    ) -> Poll<io::Result<usize>> {
+        Pin::new(&mut self.io).poll_write(cx, buf)
+    }
+
+    fn poll_write_buf<B: Buf>(
+        mut self: Pin<&mut Self>,
+        cx: &mut task::Context<'_>,
+        buf: &mut B,
+    ) -> Poll<io::Result<usize>> {
+        Pin::new(self.io.get_mut()).poll_write_dyn_buf(cx, buf)
+    }
+
+    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<io::Result<()>> {
+        Pin::new(&mut self.io).poll_flush(cx)
+    }
+
+    fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<io::Result<()>> {
+        Pin::new(&mut self.io).poll_shutdown(cx)
+    }
+}
+
+impl fmt::Debug for Upgraded {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Upgraded").finish()
+    }
+}
+
+// ===== impl OnUpgrade =====
+
+impl OnUpgrade {
+    pub(crate) fn none() -> Self {
+        OnUpgrade { rx: None }
+    }
+
+    pub(crate) fn is_none(&self) -> bool {
+        self.rx.is_none()
+    }
+}
+
+impl Future for OnUpgrade {
+    type Output = Result<Upgraded, crate::Error>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Self::Output> {
+        match self.rx {
+            Some(ref mut rx) => Pin::new(rx).poll(cx).map(|res| match res {
+                Ok(Ok(upgraded)) => Ok(upgraded),
+                Ok(Err(err)) => Err(err),
+                Err(_oneshot_canceled) => {
+                    Err(crate::Error::new_canceled().with(UpgradeExpected(())))
+                }
+            }),
+            None => Poll::Ready(Err(crate::Error::new_user_no_upgrade())),
+        }
+    }
+}
+
+impl fmt::Debug for OnUpgrade {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("OnUpgrade").finish()
+    }
+}
+
+// ===== impl Pending =====
+
+impl Pending {
+    pub(crate) fn fulfill(self, upgraded: Upgraded) {
+        trace!("pending upgrade fulfill");
+        let _ = self.tx.send(Ok(upgraded));
+    }
+
+    /// Don't fulfill the pending Upgrade, but instead signal that
+    /// upgrades are handled manually.
+    pub(crate) fn manual(self) {
+        trace!("pending upgrade handled manually");
+        let _ = self.tx.send(Err(crate::Error::new_user_manual_upgrade()));
+    }
+}
+
+// ===== impl UpgradeExpected =====
+
+impl fmt::Display for UpgradeExpected {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "upgrade expected but not completed")
+    }
+}
+
+impl StdError for UpgradeExpected {}
+
+// ===== impl Io =====
+
+struct ForwardsWriteBuf<T>(T);
+
+pub(crate) trait Io: AsyncRead + AsyncWrite + Unpin + 'static {
+    fn poll_write_dyn_buf(
+        &mut self,
+        cx: &mut task::Context<'_>,
+        buf: &mut dyn Buf,
+    ) -> Poll<io::Result<usize>>;
+
+    fn __hyper_type_id(&self) -> TypeId {
+        TypeId::of::<Self>()
+    }
+}
+
+impl dyn Io + Send {
+    fn __hyper_is<T: Io>(&self) -> bool {
+        let t = TypeId::of::<T>();
+        self.__hyper_type_id() == t
+    }
+
+    fn __hyper_downcast<T: Io>(self: Box<Self>) -> Result<Box<T>, Box<Self>> {
+        if self.__hyper_is::<T>() {
+            // Taken from `std::error::Error::downcast()`.
+            unsafe {
+                let raw: *mut dyn Io = Box::into_raw(self);
+                Ok(Box::from_raw(raw as *mut T))
+            }
+        } else {
+            Err(self)
+        }
+    }
+}
+
+impl<T: AsyncRead + Unpin> AsyncRead for ForwardsWriteBuf<T> {
+    unsafe fn prepare_uninitialized_buffer(&self, buf: &mut [std::mem::MaybeUninit<u8>]) -> bool {
+        self.0.prepare_uninitialized_buffer(buf)
+    }
+
+    fn poll_read(
+        mut self: Pin<&mut Self>,
+        cx: &mut task::Context<'_>,
+        buf: &mut [u8],
+    ) -> Poll<io::Result<usize>> {
+        Pin::new(&mut self.0).poll_read(cx, buf)
+    }
+}
+
+impl<T: AsyncWrite + Unpin> AsyncWrite for ForwardsWriteBuf<T> {
+    fn poll_write(
+        mut self: Pin<&mut Self>,
+        cx: &mut task::Context<'_>,
+        buf: &[u8],
+    ) -> Poll<io::Result<usize>> {
+        Pin::new(&mut self.0).poll_write(cx, buf)
+    }
+
+    fn poll_write_buf<B: Buf>(
+        mut self: Pin<&mut Self>,
+        cx: &mut task::Context<'_>,
+        buf: &mut B,
+    ) -> Poll<io::Result<usize>> {
+        Pin::new(&mut self.0).poll_write_buf(cx, buf)
+    }
+
+    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<io::Result<()>> {
+        Pin::new(&mut self.0).poll_flush(cx)
+    }
+
+    fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<io::Result<()>> {
+        Pin::new(&mut self.0).poll_shutdown(cx)
+    }
+}
+
+impl<T: AsyncRead + AsyncWrite + Unpin + 'static> Io for ForwardsWriteBuf<T> {
+    fn poll_write_dyn_buf(
+        &mut self,
+        cx: &mut task::Context<'_>,
+        mut buf: &mut dyn Buf,
+    ) -> Poll<io::Result<usize>> {
+        Pin::new(&mut self.0).poll_write_buf(cx, &mut buf)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tokio::io::AsyncWriteExt;
+
+    #[test]
+    fn upgraded_downcast() {
+        let upgraded = Upgraded::new(Mock, Bytes::new());
+
+        let upgraded = upgraded.downcast::<std::io::Cursor<Vec<u8>>>().unwrap_err();
+
+        upgraded.downcast::<Mock>().unwrap();
+    }
+
+    #[tokio::test]
+    async fn upgraded_forwards_write_buf() {
+        // sanity check that the underlying IO implements write_buf
+        Mock.write_buf(&mut "hello".as_bytes()).await.unwrap();
+
+        let mut upgraded = Upgraded::new(Mock, Bytes::new());
+        upgraded.write_buf(&mut "hello".as_bytes()).await.unwrap();
+    }
+
+    // TODO: replace with tokio_test::io when it can test write_buf
+    struct Mock;
+
+    impl AsyncRead for Mock {
+        fn poll_read(
+            self: Pin<&mut Self>,
+            _cx: &mut task::Context<'_>,
+            _buf: &mut [u8],
+        ) -> Poll<io::Result<usize>> {
+            unreachable!("Mock::poll_read")
+        }
+    }
+
+    impl AsyncWrite for Mock {
+        fn poll_write(
+            self: Pin<&mut Self>,
+            _cx: &mut task::Context<'_>,
+            _buf: &[u8],
+        ) -> Poll<io::Result<usize>> {
+            panic!("poll_write shouldn't be called");
+        }
+
+        fn poll_write_buf<B: Buf>(
+            self: Pin<&mut Self>,
+            _cx: &mut task::Context<'_>,
+            buf: &mut B,
+        ) -> Poll<io::Result<usize>> {
+            let n = buf.remaining();
+            buf.advance(n);
+            Poll::Ready(Ok(n))
+        }
+
+        fn poll_flush(self: Pin<&mut Self>, _cx: &mut task::Context<'_>) -> Poll<io::Result<()>> {
+            unreachable!("Mock::poll_flush")
+        }
+
+        fn poll_shutdown(
+            self: Pin<&mut Self>,
+            _cx: &mut task::Context<'_>,
+        ) -> Poll<io::Result<()>> {
+            unreachable!("Mock::poll_shutdown")
+        }
+    }
+}