Struct StreamReceiver

pub struct StreamReceiver {
    pub(crate) target: StreamTarget,
    pub(crate) receiver: StreamQueueReceiver,
    pub(crate) recv_window: RecvWindow<StreamParams>,
    pub(crate) ended: bool,
}

The read part of a stream on a particular circuit.

This Stream will return incoming messages for this Tor stream, excluding flow control related messages like SENDME, XON, and XOFF.

To avoid ambiguity, the following uses “stream” to refer to the futures::Stream, not the Tor stream.

If the stream ends unexpectedly (before an END message), the stream will return an error. After the stream returns an END message or an error, this stream will be “terminated” and future poll_next calls will return None.

Fields

target: StreamTarget

The underlying StreamTarget for this stream.

A reader has this target in order to:

• Make the reactor send SENDME messages.
• Tell the reactor when there is a protocol error.
• Keep the stream alive at least until the StreamReceiver is dropped.

receiver: StreamQueueReceiver

Channel to receive stream messages from the reactor.

recv_window: RecvWindow<StreamParams>

Congestion control receive window for this stream.

Having this here means we’re only going to update it when the end consumer of this stream actually reads things, meaning we don’t ask for more data until it’s actually needed (as opposed to having the reactor assume we’re always reading, and potentially overwhelm itself with having to buffer data).

ended: bool

Whether or not this stream has ended.

Implementations

impl StreamReceiver

pub(crate) fn project<'pin>( self: Pin<&'pin mut Self>, ) -> __StreamReceiverProjection<'pin>

pub(crate) fn project_ref<'pin>( self: Pin<&'pin Self>, ) -> __StreamReceiverProjectionRef<'pin>

impl StreamReceiver

fn poll_next_inner( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Result<Poll<UnparsedRelayMsg>>

Try to read the next relay message from this stream.

pub fn protocol_error(&mut self)

Shut down this stream.

pub(crate) fn is_empty(&mut self) -> bool

Is the stream currently empty?

This method is inherently subject to race conditions. More data may arrive even before this method returns, so a result of true might have been outdated before the method even returned.

This takes a &mut so that we can peek the stream.

We provide an is_empty method rather than implementing [UnobtrusivePeekableStream] directly since UnobtrusivePeekableStream allows you to mutate the peeked item, which could break any accounting we do here in StreamReceiver (like stream sendme accounting). Also the stream types are incompatible (the inner receiver returns items of UnparsedRelayMsg, but this StreamReceiver returns items of Result<UnparsedRelayMsg>).

Trait Implementations

impl Debug for StreamReceiver

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Stream for StreamReceiver

type Item = Result<UnparsedRelayMsg, Error>

Values yielded by the stream.

fn poll_next( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Option<Self::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream.

impl<'pin> Unpin for StreamReceiver

where PinnedFieldsOf<__StreamReceiver<'pin>>: Unpin,