Files
2026-07-08 16:23:51 -04:00

105 lines
2.4 KiB
Go

/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package ttrpc
import (
"context"
"sync"
"time"
)
type streamID uint32
type streamMessage struct {
header messageHeader
payload []byte
}
type stream struct {
id streamID
sender sender
recv chan *streamMessage
closeOnce sync.Once
recvErr error
recvClose chan struct{}
}
func newStream(id streamID, send sender, recvBuf int) *stream {
return &stream{
id: id,
sender: send,
recv: make(chan *streamMessage, recvBuf),
recvClose: make(chan struct{}),
}
}
func (s *stream) closeWithError(err error) error {
s.closeOnce.Do(func() {
if err != nil {
s.recvErr = err
} else {
s.recvErr = ErrClosed
}
close(s.recvClose)
})
return nil
}
func (s *stream) send(mt messageType, flags uint8, b []byte) error {
return s.sender.send(uint32(s.id), mt, flags, b)
}
// receive delivers a message to this stream from the connection receive loop.
// If the stream's recv buffer is full, it waits up to 1 second for the
// consumer to make progress. This keeps the receive loop moving for other
// streams while still providing backpressure under normal operation. If the
// timeout expires the stream is closed with ErrStreamFull.
func (s *stream) receive(ctx context.Context, msg *streamMessage) error {
select {
case <-s.recvClose:
return s.recvErr
default:
}
select {
case <-s.recvClose:
return s.recvErr
case s.recv <- msg:
return nil
case <-ctx.Done():
return ctx.Err()
default:
// If recv channel is full, wait up to a second for an item
// to drain and unblock, otherwise close the stream.
select {
case <-s.recvClose:
return s.recvErr
case s.recv <- msg:
return nil
case <-ctx.Done():
return ctx.Err()
case <-time.After(time.Second):
s.closeWithError(ErrStreamFull)
return ErrStreamFull
}
}
}
type sender interface {
send(uint32, messageType, uint8, []byte) error
}