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receive_stream.go
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receive_stream.go
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package quic
import (
"fmt"
"io"
"sync"
"time"
"github.com/quic-go/quic-go/internal/flowcontrol"
"github.com/quic-go/quic-go/internal/protocol"
"github.com/quic-go/quic-go/internal/qerr"
"github.com/quic-go/quic-go/internal/utils"
"github.com/quic-go/quic-go/internal/wire"
)
type receiveStreamI interface {
ReceiveStream
handleStreamFrame(*wire.StreamFrame) error
handleResetStreamFrame(*wire.ResetStreamFrame) error
closeForShutdown(error)
getWindowUpdate() protocol.ByteCount
}
type receiveStream struct {
mutex sync.Mutex
streamID protocol.StreamID
sender streamSender
frameQueue *frameSorter
finalOffset protocol.ByteCount
currentFrame []byte
currentFrameDone func()
readPosInFrame int
currentFrameIsLast bool // is the currentFrame the last frame on this stream
// Set once we read the io.EOF or the cancellation error.
// Note that for local cancellations, this doesn't necessarily mean that we know the final offset yet.
errorRead bool
completed bool // set once we've called streamSender.onStreamCompleted
cancelledRemotely bool
cancelledLocally bool
cancelErr *StreamError
closeForShutdownErr error
readChan chan struct{}
readOnce chan struct{} // cap: 1, to protect against concurrent use of Read
deadline time.Time
flowController flowcontrol.StreamFlowController
}
var (
_ ReceiveStream = &receiveStream{}
_ receiveStreamI = &receiveStream{}
)
func newReceiveStream(
streamID protocol.StreamID,
sender streamSender,
flowController flowcontrol.StreamFlowController,
) *receiveStream {
return &receiveStream{
streamID: streamID,
sender: sender,
flowController: flowController,
frameQueue: newFrameSorter(),
readChan: make(chan struct{}, 1),
readOnce: make(chan struct{}, 1),
finalOffset: protocol.MaxByteCount,
}
}
func (s *receiveStream) StreamID() protocol.StreamID {
return s.streamID
}
// Read implements io.Reader. It is not thread safe!
func (s *receiveStream) Read(p []byte) (int, error) {
// Concurrent use of Read is not permitted (and doesn't make any sense),
// but sometimes people do it anyway.
// Make sure that we only execute one call at any given time to avoid hard to debug failures.
s.readOnce <- struct{}{}
defer func() { <-s.readOnce }()
s.mutex.Lock()
n, err := s.readImpl(p)
completed := s.isNewlyCompleted()
s.mutex.Unlock()
if completed {
s.sender.onStreamCompleted(s.streamID)
}
return n, err
}
func (s *receiveStream) isNewlyCompleted() bool {
if s.completed {
return false
}
// We need to know the final offset (either via FIN or RESET_STREAM) for flow control accounting.
if s.finalOffset == protocol.MaxByteCount {
return false
}
// We're done with the stream if it was cancelled locally...
if s.cancelledLocally {
s.completed = true
return true
}
// ... or if the error (either io.EOF or the reset error) was read
if s.errorRead {
s.completed = true
return true
}
return false
}
func (s *receiveStream) readImpl(p []byte) (int, error) {
if s.currentFrameIsLast && s.currentFrame == nil {
s.errorRead = true
return 0, io.EOF
}
if s.cancelledRemotely || s.cancelledLocally {
s.errorRead = true
return 0, s.cancelErr
}
if s.closeForShutdownErr != nil {
return 0, s.closeForShutdownErr
}
var bytesRead int
var deadlineTimer *utils.Timer
for bytesRead < len(p) {
if s.currentFrame == nil || s.readPosInFrame >= len(s.currentFrame) {
s.dequeueNextFrame()
}
if s.currentFrame == nil && bytesRead > 0 {
return bytesRead, s.closeForShutdownErr
}
for {
// Stop waiting on errors
if s.closeForShutdownErr != nil {
return bytesRead, s.closeForShutdownErr
}
if s.cancelledRemotely || s.cancelledLocally {
s.errorRead = true
return 0, s.cancelErr
}
deadline := s.deadline
if !deadline.IsZero() {
if !time.Now().Before(deadline) {
return bytesRead, errDeadline
}
if deadlineTimer == nil {
deadlineTimer = utils.NewTimer()
defer deadlineTimer.Stop()
}
deadlineTimer.Reset(deadline)
}
if s.currentFrame != nil || s.currentFrameIsLast {
break
}
s.mutex.Unlock()
if deadline.IsZero() {
<-s.readChan
} else {
select {
case <-s.readChan:
case <-deadlineTimer.Chan():
deadlineTimer.SetRead()
}
}
s.mutex.Lock()
if s.currentFrame == nil {
s.dequeueNextFrame()
}
}
if bytesRead > len(p) {
return bytesRead, fmt.Errorf("BUG: bytesRead (%d) > len(p) (%d) in stream.Read", bytesRead, len(p))
}
if s.readPosInFrame > len(s.currentFrame) {
return bytesRead, fmt.Errorf("BUG: readPosInFrame (%d) > frame.DataLen (%d) in stream.Read", s.readPosInFrame, len(s.currentFrame))
}
m := copy(p[bytesRead:], s.currentFrame[s.readPosInFrame:])
s.readPosInFrame += m
bytesRead += m
// when a RESET_STREAM was received, the flow controller was already
// informed about the final byteOffset for this stream
if !s.cancelledRemotely {
if queueWindowUpdate := s.flowController.AddBytesRead(protocol.ByteCount(m)); queueWindowUpdate {
s.sender.onHasStreamWindowUpdate(s.streamID, s)
}
}
if s.readPosInFrame >= len(s.currentFrame) && s.currentFrameIsLast {
s.currentFrame = nil
if s.currentFrameDone != nil {
s.currentFrameDone()
}
s.errorRead = true
return bytesRead, io.EOF
}
}
return bytesRead, nil
}
func (s *receiveStream) dequeueNextFrame() {
var offset protocol.ByteCount
// We're done with the last frame. Release the buffer.
if s.currentFrameDone != nil {
s.currentFrameDone()
}
offset, s.currentFrame, s.currentFrameDone = s.frameQueue.Pop()
s.currentFrameIsLast = offset+protocol.ByteCount(len(s.currentFrame)) >= s.finalOffset
s.readPosInFrame = 0
}
func (s *receiveStream) CancelRead(errorCode StreamErrorCode) {
s.mutex.Lock()
s.cancelReadImpl(errorCode)
completed := s.isNewlyCompleted()
s.mutex.Unlock()
if completed {
s.flowController.Abandon()
s.sender.onStreamCompleted(s.streamID)
}
}
func (s *receiveStream) cancelReadImpl(errorCode qerr.StreamErrorCode) {
if s.cancelledLocally { // duplicate call to CancelRead
return
}
s.cancelledLocally = true
if s.errorRead || s.cancelledRemotely {
return
}
s.cancelErr = &StreamError{StreamID: s.streamID, ErrorCode: errorCode, Remote: false}
s.signalRead()
s.sender.queueControlFrame(&wire.StopSendingFrame{
StreamID: s.streamID,
ErrorCode: errorCode,
})
}
func (s *receiveStream) handleStreamFrame(frame *wire.StreamFrame) error {
s.mutex.Lock()
err := s.handleStreamFrameImpl(frame)
completed := s.isNewlyCompleted()
s.mutex.Unlock()
if completed {
s.flowController.Abandon()
s.sender.onStreamCompleted(s.streamID)
}
return err
}
func (s *receiveStream) handleStreamFrameImpl(frame *wire.StreamFrame) error {
maxOffset := frame.Offset + frame.DataLen()
if err := s.flowController.UpdateHighestReceived(maxOffset, frame.Fin); err != nil {
return err
}
if frame.Fin {
s.finalOffset = maxOffset
}
if s.cancelledLocally {
return nil
}
if err := s.frameQueue.Push(frame.Data, frame.Offset, frame.PutBack); err != nil {
return err
}
s.signalRead()
return nil
}
func (s *receiveStream) handleResetStreamFrame(frame *wire.ResetStreamFrame) error {
s.mutex.Lock()
err := s.handleResetStreamFrameImpl(frame)
completed := s.isNewlyCompleted()
s.mutex.Unlock()
if completed {
s.sender.onStreamCompleted(s.streamID)
}
return err
}
func (s *receiveStream) handleResetStreamFrameImpl(frame *wire.ResetStreamFrame) error {
if s.closeForShutdownErr != nil {
return nil
}
if err := s.flowController.UpdateHighestReceived(frame.FinalSize, true); err != nil {
return err
}
s.finalOffset = frame.FinalSize
// ignore duplicate RESET_STREAM frames for this stream (after checking their final offset)
if s.cancelledRemotely {
return nil
}
s.flowController.Abandon()
// don't save the error if the RESET_STREAM frames was received after CancelRead was called
if s.cancelledLocally {
return nil
}
s.cancelledRemotely = true
s.cancelErr = &StreamError{StreamID: s.streamID, ErrorCode: frame.ErrorCode, Remote: true}
s.signalRead()
return nil
}
func (s *receiveStream) SetReadDeadline(t time.Time) error {
s.mutex.Lock()
s.deadline = t
s.mutex.Unlock()
s.signalRead()
return nil
}
// CloseForShutdown closes a stream abruptly.
// It makes Read unblock (and return the error) immediately.
// The peer will NOT be informed about this: the stream is closed without sending a FIN or RESET.
func (s *receiveStream) closeForShutdown(err error) {
s.mutex.Lock()
s.closeForShutdownErr = err
s.mutex.Unlock()
s.signalRead()
}
func (s *receiveStream) getWindowUpdate() protocol.ByteCount {
return s.flowController.GetWindowUpdate()
}
// signalRead performs a non-blocking send on the readChan
func (s *receiveStream) signalRead() {
select {
case s.readChan <- struct{}{}:
default:
}
}