Reduce memory allocations in NextReader, NextWriter

This commit is contained in:
Gary Burd 2016-05-26 14:07:24 -07:00
parent 2301bcbf5c
commit 8b209f6317
2 changed files with 82 additions and 83 deletions

View File

@ -3,7 +3,6 @@ sudo: false
matrix:
include:
- go: 1.4
- go: 1.5
- go: 1.6
- go: tip

160
conn.go
View File

@ -238,16 +238,15 @@ type Conn struct {
writeBuf []byte // frame is constructed in this buffer.
writePos int // end of data in writeBuf.
writeFrameType int // type of the current frame.
writeSeq int // incremented to invalidate message writers.
writeDeadline time.Time
isWriting bool // for best-effort concurrent write detection
messageWriter *messageWriter // the current writer
// Read fields
readErr error
br *bufio.Reader
readRemaining int64 // bytes remaining in current frame.
readFinal bool // true the current message has more frames.
readSeq int // incremented to invalidate message readers.
readLength int64 // Message size.
readLimit int64 // Maximum message size.
readMaskPos int
@ -255,6 +254,7 @@ type Conn struct {
handlePong func(string) error
handlePing func(string) error
readErrCount int
messageReader *messageReader // the current reader
}
func newConn(conn net.Conn, isServer bool, readBufferSize, writeBufferSize int) *Conn {
@ -264,6 +264,9 @@ func newConn(conn net.Conn, isServer bool, readBufferSize, writeBufferSize int)
if readBufferSize == 0 {
readBufferSize = defaultReadBufferSize
}
if readBufferSize < maxControlFramePayloadSize {
readBufferSize = maxControlFramePayloadSize
}
if writeBufferSize == 0 {
writeBufferSize = defaultWriteBufferSize
}
@ -390,8 +393,8 @@ func (c *Conn) WriteControl(messageType int, data []byte, deadline time.Time) er
return hideTempErr(err)
}
// NextWriter returns a writer for the next message to send. The writer's
// Close method flushes the complete message to the network.
// NextWriter returns a writer for the next message to send. The writer's Close
// method flushes the complete message to the network.
//
// There can be at most one open writer on a connection. NextWriter closes the
// previous writer if the application has not already done so.
@ -411,7 +414,9 @@ func (c *Conn) NextWriter(messageType int) (io.WriteCloser, error) {
}
c.writeFrameType = messageType
return messageWriter{c, c.writeSeq}, nil
w := &messageWriter{c}
c.messageWriter = w
return w, nil
}
func (c *Conn) flushFrame(final bool, extra []byte) error {
@ -420,7 +425,7 @@ func (c *Conn) flushFrame(final bool, extra []byte) error {
// Check for invalid control frames.
if isControl(c.writeFrameType) &&
(!final || length > maxControlFramePayloadSize) {
c.writeSeq++
c.messageWriter = nil
c.writeFrameType = noFrame
c.writePos = maxFrameHeaderSize
return errInvalidControlFrame
@ -488,20 +493,17 @@ func (c *Conn) flushFrame(final bool, extra []byte) error {
c.writePos = maxFrameHeaderSize
c.writeFrameType = continuationFrame
if final {
c.writeSeq++
c.messageWriter = nil
c.writeFrameType = noFrame
}
return c.writeErr
}
type messageWriter struct {
c *Conn
seq int
}
type messageWriter struct{ c *Conn }
func (w messageWriter) err() error {
func (w *messageWriter) err() error {
c := w.c
if c.writeSeq != w.seq {
if c.messageWriter != w {
return errWriteClosed
}
if c.writeErr != nil {
@ -510,7 +512,7 @@ func (w messageWriter) err() error {
return nil
}
func (w messageWriter) ncopy(max int) (int, error) {
func (w *messageWriter) ncopy(max int) (int, error) {
n := len(w.c.writeBuf) - w.c.writePos
if n <= 0 {
if err := w.c.flushFrame(false, nil); err != nil {
@ -524,7 +526,7 @@ func (w messageWriter) ncopy(max int) (int, error) {
return n, nil
}
func (w messageWriter) write(final bool, p []byte) (int, error) {
func (w *messageWriter) write(final bool, p []byte) (int, error) {
if err := w.err(); err != nil {
return 0, err
}
@ -551,11 +553,11 @@ func (w messageWriter) write(final bool, p []byte) (int, error) {
return nn, nil
}
func (w messageWriter) Write(p []byte) (int, error) {
func (w *messageWriter) Write(p []byte) (int, error) {
return w.write(false, p)
}
func (w messageWriter) WriteString(p string) (int, error) {
func (w *messageWriter) WriteString(p string) (int, error) {
if err := w.err(); err != nil {
return 0, err
}
@ -573,7 +575,7 @@ func (w messageWriter) WriteString(p string) (int, error) {
return nn, nil
}
func (w messageWriter) ReadFrom(r io.Reader) (nn int64, err error) {
func (w *messageWriter) ReadFrom(r io.Reader) (nn int64, err error) {
if err := w.err(); err != nil {
return 0, err
}
@ -598,7 +600,7 @@ func (w messageWriter) ReadFrom(r io.Reader) (nn int64, err error) {
return nn, err
}
func (w messageWriter) Close() error {
func (w *messageWriter) Close() error {
if err := w.err(); err != nil {
return err
}
@ -608,20 +610,22 @@ func (w messageWriter) Close() error {
// WriteMessage is a helper method for getting a writer using NextWriter,
// writing the message and closing the writer.
func (c *Conn) WriteMessage(messageType int, data []byte) error {
wr, err := c.NextWriter(messageType)
w, err := c.NextWriter(messageType)
if err != nil {
return err
}
w := wr.(messageWriter)
if _, err := w.write(true, data); err != nil {
if _, ok := w.(*messageWriter); ok && c.isServer {
// Optimize write as a single frame.
n := copy(c.writeBuf[c.writePos:], data)
c.writePos += n
data = data[n:]
err = c.flushFrame(true, data)
return err
}
if c.writeSeq == w.seq {
if err := c.flushFrame(true, nil); err != nil {
if _, err = w.Write(data); err != nil {
return err
}
}
return nil
return w.Close()
}
// SetWriteDeadline sets the write deadline on the underlying network
@ -635,20 +639,13 @@ func (c *Conn) SetWriteDeadline(t time.Time) error {
// Read methods
// readFull is like io.ReadFull except that io.EOF is never returned.
func (c *Conn) readFull(p []byte) (err error) {
var n int
for n < len(p) && err == nil {
var nn int
nn, err = c.br.Read(p[n:])
n += nn
}
if n == len(p) {
err = nil
} else if err == io.EOF {
func (c *Conn) read(n int) ([]byte, error) {
p, err := c.br.Peek(n)
if err == io.EOF {
err = errUnexpectedEOF
}
return
c.br.Discard(len(p))
return p, err
}
func (c *Conn) advanceFrame() (int, error) {
@ -663,16 +660,16 @@ func (c *Conn) advanceFrame() (int, error) {
// 2. Read and parse first two bytes of frame header.
var b [8]byte
if err := c.readFull(b[:2]); err != nil {
p, err := c.read(2)
if err != nil {
return noFrame, err
}
final := b[0]&finalBit != 0
frameType := int(b[0] & 0xf)
reserved := int((b[0] >> 4) & 0x7)
mask := b[1]&maskBit != 0
c.readRemaining = int64(b[1] & 0x7f)
final := p[0]&finalBit != 0
frameType := int(p[0] & 0xf)
reserved := int((p[0] >> 4) & 0x7)
mask := p[1]&maskBit != 0
c.readRemaining = int64(p[1] & 0x7f)
if reserved != 0 {
return noFrame, c.handleProtocolError("unexpected reserved bits " + strconv.Itoa(reserved))
@ -704,15 +701,17 @@ func (c *Conn) advanceFrame() (int, error) {
switch c.readRemaining {
case 126:
if err := c.readFull(b[:2]); err != nil {
p, err := c.read(2)
if err != nil {
return noFrame, err
}
c.readRemaining = int64(binary.BigEndian.Uint16(b[:2]))
c.readRemaining = int64(binary.BigEndian.Uint16(p))
case 127:
if err := c.readFull(b[:8]); err != nil {
p, err := c.read(8)
if err != nil {
return noFrame, err
}
c.readRemaining = int64(binary.BigEndian.Uint64(b[:8]))
c.readRemaining = int64(binary.BigEndian.Uint64(p))
}
// 4. Handle frame masking.
@ -723,9 +722,11 @@ func (c *Conn) advanceFrame() (int, error) {
if mask {
c.readMaskPos = 0
if err := c.readFull(c.readMaskKey[:]); err != nil {
p, err := c.read(len(c.readMaskKey))
if err != nil {
return noFrame, err
}
copy(c.readMaskKey[:], p)
}
// 5. For text and binary messages, enforce read limit and return.
@ -745,9 +746,9 @@ func (c *Conn) advanceFrame() (int, error) {
var payload []byte
if c.readRemaining > 0 {
payload = make([]byte, c.readRemaining)
payload, err = c.read(int(c.readRemaining))
c.readRemaining = 0
if err := c.readFull(payload); err != nil {
if err != nil {
return noFrame, err
}
if c.isServer {
@ -805,7 +806,7 @@ func (c *Conn) handleProtocolError(message string) error {
// this method return the same error.
func (c *Conn) NextReader() (messageType int, r io.Reader, err error) {
c.readSeq++
c.messageReader = nil
c.readLength = 0
for c.readErr == nil {
@ -815,7 +816,9 @@ func (c *Conn) NextReader() (messageType int, r io.Reader, err error) {
break
}
if frameType == TextMessage || frameType == BinaryMessage {
return frameType, messageReader{c, c.readSeq}, nil
r := &messageReader{c}
c.messageReader = r
return frameType, r, nil
}
}
@ -830,51 +833,48 @@ func (c *Conn) NextReader() (messageType int, r io.Reader, err error) {
return noFrame, nil, c.readErr
}
type messageReader struct {
c *Conn
seq int
}
type messageReader struct{ c *Conn }
func (r messageReader) Read(b []byte) (int, error) {
if r.seq != r.c.readSeq {
func (r *messageReader) Read(b []byte) (int, error) {
c := r.c
if c.messageReader != r {
return 0, io.EOF
}
for r.c.readErr == nil {
for c.readErr == nil {
if r.c.readRemaining > 0 {
if int64(len(b)) > r.c.readRemaining {
b = b[:r.c.readRemaining]
if c.readRemaining > 0 {
if int64(len(b)) > c.readRemaining {
b = b[:c.readRemaining]
}
n, err := r.c.br.Read(b)
r.c.readErr = hideTempErr(err)
if r.c.isServer {
r.c.readMaskPos = maskBytes(r.c.readMaskKey, r.c.readMaskPos, b[:n])
n, err := c.br.Read(b)
c.readErr = hideTempErr(err)
if c.isServer {
c.readMaskPos = maskBytes(c.readMaskKey, c.readMaskPos, b[:n])
}
r.c.readRemaining -= int64(n)
if r.c.readRemaining > 0 && r.c.readErr == io.EOF {
r.c.readErr = errUnexpectedEOF
c.readRemaining -= int64(n)
if c.readRemaining > 0 && c.readErr == io.EOF {
c.readErr = errUnexpectedEOF
}
return n, r.c.readErr
return n, c.readErr
}
if r.c.readFinal {
r.c.readSeq++
if c.readFinal {
c.messageReader = nil
return 0, io.EOF
}
frameType, err := r.c.advanceFrame()
frameType, err := c.advanceFrame()
switch {
case err != nil:
r.c.readErr = hideTempErr(err)
c.readErr = hideTempErr(err)
case frameType == TextMessage || frameType == BinaryMessage:
r.c.readErr = errors.New("websocket: internal error, unexpected text or binary in Reader")
c.readErr = errors.New("websocket: internal error, unexpected text or binary in Reader")
}
}
err := r.c.readErr
if err == io.EOF && r.seq == r.c.readSeq {
err := c.readErr
if err == io.EOF && c.messageReader == r {
err = errUnexpectedEOF
}
return 0, err