func (p *PushStream) Finish() {
p.writeHeader()
end := new(frames.DATA)
end.StreamID = p.streamID
end.Data = []byte{}
end.Flags = common.FLAG_FIN
p.output <- end
p.Close()
}
// Write is used to send data to the connection. This
// takes care of the windowing. Although data may be
// buffered, rather than actually sent, this is not
// visible to the caller.
func (f *flowControl) Write(data []byte) (int, error) {
l := len(data)
if l == 0 {
return 0, nil
}
if f.buffer == nil || f.stream == nil {
return 0, errors.New("Error: Stream closed.")
}
// Transfer window processing.
f.CheckInitialWindow()
if f.constrained {
f.Flush()
}
f.Lock()
var window uint32
if f.transferWindow < 0 {
window = 0
} else {
window = uint32(f.transferWindow)
}
constrained := false
sending := uint32(len(data))
if sending > window {
sending = window
constrained = true
}
f.sent += sending
f.transferWindow -= int64(sending)
if constrained {
f.buffer = append(f.buffer, data[window:])
data = data[:window]
f.constrained = true
debug.Printf("Stream %d is now constrained.\n", f.streamID)
}
f.Unlock()
if len(data) == 0 {
return l, nil
}
dataFrame := new(frames.DATA)
dataFrame.StreamID = f.streamID
dataFrame.Data = data
f.output <- dataFrame
return l, nil
}
// Flush is used to send buffered data to
// the connection, if the transfer window
// will allow. Flush does not guarantee
// that any or all buffered data will be
// sent with a single flush.
func (f *flowControl) Flush() {
f.CheckInitialWindow()
if !f.constrained || f.transferWindow == 0 {
return
}
out := make([]byte, 0, f.transferWindow)
left := f.transferWindow
for i := 0; i < len(f.buffer); i++ {
if l := int64(len(f.buffer[i])); l <= left {
out = append(out, f.buffer[i]...)
left -= l
f.buffer = f.buffer[1:]
} else {
out = append(out, f.buffer[i][:left]...)
f.buffer[i] = f.buffer[i][left:]
left = 0
}
if left == 0 {
break
}
}
f.transferWindow -= int64(len(out))
if f.transferWindow > 0 {
f.constrained = false
debug.Printf("Stream %d is no longer constrained.\n", f.streamID)
}
dataFrame := new(frames.DATA)
dataFrame.StreamID = f.streamID
dataFrame.Data = out
f.output <- dataFrame
}
// run is the main control path of
// the stream. It is prepared, the
// registered handler is called,
// and then the stream is cleaned
// up and closed.
func (s *ResponseStream) Run() error {
// Catch any panics.
defer func() {
if v := recover(); v != nil {
if s != nil && s.state != nil && !s.state.Closed() {
log.Printf("Encountered stream error: %v (%[1]T)\n", v)
}
}
}()
// Make sure Request is prepared.
if s.requestBody == nil || s.request.Body == nil {
s.requestBody = new(bytes.Buffer)
s.request.Body = &common.ReadCloser{s.requestBody}
}
// Wait until the full request has been received.
<-s.ready
/***************
*** HANDLER ***
***************/
s.handler.ServeHTTP(s, s.request)
// Make sure any queued data has been sent.
if err := s.flow.Wait(); err != nil {
log.Println(err)
}
// Close the stream with a SYN_REPLY if
// none has been sent, or an empty DATA
// frame, if a SYN_REPLY has been sent
// already.
// If the stream is already closed at
// this end, then nothing happens.
if !s.unidirectional {
if s.state.OpenHere() && !s.wroteHeader {
s.header.Set(":status", "200")
s.header.Set(":version", "HTTP/1.1")
// Create the response SYN_REPLY.
synReply := new(frames.SYN_REPLY)
synReply.Flags = common.FLAG_FIN
synReply.StreamID = s.streamID
synReply.Header = make(http.Header)
for name, values := range s.header {
for _, value := range values {
synReply.Header.Add(name, value)
}
s.header.Del(name)
}
s.output <- synReply
} else if s.state.OpenHere() {
// Create the DATA.
data := new(frames.DATA)
data.StreamID = s.streamID
data.Flags = common.FLAG_FIN
data.Data = []byte{}
s.output <- data
}
}
// Clean up state.
s.state.CloseHere()
if s.state.Closed() {
return s.Close()
}
return nil
}
// send is run in a separate goroutine. It's used
// to ensure clear interleaving of frames and to
// provide assurances of priority and structure.
func (c *Conn) send() {
// Catch any panics.
defer func() {
if v := recover(); v != nil {
if !c.Closed() {
log.Printf("Encountered send error: %v (%[1]T)\n", v)
}
}
}()
for i := 1; ; i++ {
if i >= 5 {
i = 0 // Once per 5 frames, pick randomly.
}
var frame common.Frame
if i == 0 { // Ignore priority.
frame = c.selectFrameToSend(false)
} else { // Normal selection.
frame = c.selectFrameToSend(true)
}
if frame == nil {
c.Close()
return
}
// Process connection-level flow control.
if c.Subversion > 0 {
c.connectionWindowLock.Lock()
if frame, ok := frame.(*frames.DATA); ok {
size := int64(len(frame.Data))
constrained := false
sending := size
if sending > c.connectionWindowSize {
sending = c.connectionWindowSize
constrained = true
}
if sending < 0 {
sending = 0
}
c.connectionWindowSize -= sending
if constrained {
// Chop off what we can send now.
partial := new(frames.DATA)
partial.Flags = frame.Flags
partial.StreamID = frame.StreamID
partial.Data = make([]byte, int(sending))
copy(partial.Data, frame.Data[:sending])
frame.Data = frame.Data[sending:]
// Buffer this frame and try again.
if c.dataBuffer == nil {
c.dataBuffer = []*frames.DATA{frame}
} else {
buffer := make([]*frames.DATA, 1, len(c.dataBuffer)+1)
buffer[0] = frame
buffer = append(buffer, c.dataBuffer...)
c.dataBuffer = buffer
}
frame = partial
}
}
c.connectionWindowLock.Unlock()
}
// Compress any name/value header blocks.
err := frame.Compress(c.compressor)
if err != nil {
log.Printf("Error in compression: %v (type %T).\n", err, frame)
c.Close()
return
}
debug.Printf("Sending %s:\n", frame.Name())
debug.Println(frame)
// Leave the specifics of writing to the
// connection up to the frame.
c.refreshWriteTimeout()
if _, err = frame.WriteTo(c.conn); err != nil {
c.handleReadWriteError(err)
return
}
}
}