third_party/rust_crates/vendor/hyper/src/upgrade.rs - fuchsia - Git at Google

 //! 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")
         }
     }
 }
	//! 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")
	}
	}
	}