generated from RTradeLtd/repo-template
/
stream.go
298 lines (244 loc) · 4.89 KB
/
stream.go
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package multiplex
import (
"context"
"errors"
"io"
"sync"
"time"
"github.com/RTradeLtd/libp2px-core/mux"
pool "github.com/RTradeLtd/libp2px/pkg/buffer-pool"
)
// streamID is a convenience type for operating on stream IDs
type streamID struct {
id uint64
initiator bool
}
// header computes the header for the given tag
func (id *streamID) header(tag uint64) uint64 {
header := id.id<<3 | tag
if !id.initiator {
header--
}
return header
}
// Stream is a stream !
type Stream struct {
id streamID
name string
dataIn chan []byte
mp *Multiplex
extra []byte
// exbuf is for holding the reference to the beginning of the extra slice
// for later memory pool freeing
exbuf []byte
rDeadline, wDeadline pipeDeadline
clLock sync.Mutex
closedRemote bool
// Closed when the connection is reset.
reset chan struct{}
// Closed when the writer is closed (reset will also be closed)
closedLocal context.Context
doCloseLocal context.CancelFunc
}
// Name returns the name of the stream
func (s *Stream) Name() string {
return s.name
}
// tries to preload pending data
func (s *Stream) preloadData() {
select {
case read, ok := <-s.dataIn:
if !ok {
return
}
s.extra = read
s.exbuf = read
default:
}
}
func (s *Stream) waitForData() error {
select {
case <-s.reset:
// This is the only place where it's safe to return these.
s.returnBuffers()
return mux.ErrReset
case read, ok := <-s.dataIn:
if !ok {
return io.EOF
}
s.extra = read
s.exbuf = read
return nil
case <-s.rDeadline.wait():
return errTimeout
}
}
func (s *Stream) returnBuffers() {
if s.exbuf != nil {
pool.Put(s.exbuf)
s.exbuf = nil
s.extra = nil
}
for {
select {
case read, ok := <-s.dataIn:
if !ok {
return
}
if read == nil {
continue
}
pool.Put(read)
default:
return
}
}
}
func (s *Stream) Read(b []byte) (int, error) {
select {
case <-s.reset:
return 0, mux.ErrReset
default:
}
if s.extra == nil {
err := s.waitForData()
if err != nil {
return 0, err
}
}
n := 0
for s.extra != nil && n < len(b) {
read := copy(b[n:], s.extra)
n += read
if read < len(s.extra) {
s.extra = s.extra[read:]
} else {
if s.exbuf != nil {
pool.Put(s.exbuf)
}
s.extra = nil
s.exbuf = nil
s.preloadData()
}
}
return n, nil
}
func (s *Stream) Write(b []byte) (int, error) {
var written int
for written < len(b) {
wl := len(b) - written
if wl > MaxMessageSize {
wl = MaxMessageSize
}
n, err := s.write(b[written : written+wl])
if err != nil {
return written, err
}
written += n
}
return written, nil
}
func (s *Stream) write(b []byte) (int, error) {
if s.isClosed() {
return 0, errors.New("cannot write to closed stream")
}
err := s.mp.sendMsg(s.wDeadline.wait(), s.id.header(messageTag), b)
if err != nil {
if err == context.Canceled {
err = errors.New("cannot write to closed stream")
}
return 0, err
}
return len(b), nil
}
func (s *Stream) isClosed() bool {
return s.closedLocal.Err() != nil
}
// Close shuts down the stream
func (s *Stream) Close() error {
ctx, cancel := context.WithTimeout(context.Background(), ResetStreamTimeout)
defer cancel()
err := s.mp.sendMsg(ctx.Done(), s.id.header(closeTag), nil)
if s.isClosed() {
return nil
}
s.clLock.Lock()
remote := s.closedRemote
s.clLock.Unlock()
s.doCloseLocal()
if remote {
s.cancelDeadlines()
s.mp.chLock.Lock()
delete(s.mp.channels, s.id)
s.mp.chLock.Unlock()
}
if err != nil && !s.mp.isShutdown() {
s.mp.Close()
}
return err
}
// Reset is used to reset the stream
func (s *Stream) Reset() error {
s.clLock.Lock()
// Don't reset when fully closed.
if s.closedRemote && s.isClosed() {
s.clLock.Unlock()
return nil
}
// Don't reset twice.
select {
case <-s.reset:
s.clLock.Unlock()
return nil
default:
}
close(s.reset)
s.doCloseLocal()
s.closedRemote = true
s.cancelDeadlines()
go s.mp.sendResetMsg(s.id.header(resetTag), true)
s.clLock.Unlock()
s.mp.chLock.Lock()
delete(s.mp.channels, s.id)
s.mp.chLock.Unlock()
return nil
}
func (s *Stream) cancelDeadlines() {
s.rDeadline.set(time.Time{})
s.wDeadline.set(time.Time{})
}
// SetDeadline sets a general deadline timeout
func (s *Stream) SetDeadline(t time.Time) error {
s.clLock.Lock()
defer s.clLock.Unlock()
if s.closedRemote && s.isClosed() {
return errStreamClosed
}
if !s.closedRemote {
s.rDeadline.set(t)
}
if !s.isClosed() {
s.wDeadline.set(t)
}
return nil
}
// SetReadDeadline sets the read deadline timeout
func (s *Stream) SetReadDeadline(t time.Time) error {
s.clLock.Lock()
defer s.clLock.Unlock()
if s.closedRemote {
return errStreamClosed
}
s.rDeadline.set(t)
return nil
}
// SetWriteDeadline sets the write deadline timeout
func (s *Stream) SetWriteDeadline(t time.Time) error {
s.clLock.Lock()
defer s.clLock.Unlock()
if s.isClosed() {
return errStreamClosed
}
s.wDeadline.set(t)
return nil
}