Merge pull request #138 from notsure2/explicit-stop-timer

Optimise calls to time.AfterFunc in buffered pipe implemenations to reduce memory usage

internal/multiplex/datagramBufferedPipe.go

@@ -20,6 +20,8 @@ type datagramBufferedPipe struct {
 	rwCond    *sync.Cond
 	wtTimeout time.Duration
 	rDeadline time.Time
+
+	timeoutTimer *time.Timer
 }
 
 func NewDatagramBufferedPipe() *datagramBufferedPipe {
@@ -40,17 +42,20 @@ func (d *datagramBufferedPipe) Read(target []byte) (int, error) {
 			return 0, io.EOF
 		}
 
-		if !d.rDeadline.IsZero() {
-			delta := time.Until(d.rDeadline)
-			if delta <= 0 {
+		hasRDeadline := !d.rDeadline.IsZero()
+		if hasRDeadline {
+			if time.Until(d.rDeadline) <= 0 {
 				return 0, ErrTimeout
 			}
-			time.AfterFunc(delta, d.rwCond.Broadcast)
 		}
 
 		if len(d.pLens) > 0 {
 			break
 		}
+
+		if hasRDeadline {
+			d.broadcastAfter(time.Until(d.rDeadline))
+		}
 		d.rwCond.Wait()
 	}
 	dataLen := d.pLens[0]
@@ -74,19 +79,12 @@ func (d *datagramBufferedPipe) WriteTo(w io.Writer) (n int64, err error) {
 		if d.closed && len(d.pLens) == 0 {
 			return 0, io.EOF
 		}
-		if !d.rDeadline.IsZero() {
-			delta := time.Until(d.rDeadline)
-			if delta <= 0 {
+
+		hasRDeadline := !d.rDeadline.IsZero()
+		if hasRDeadline {
+			if time.Until(d.rDeadline) <= 0 {
 				return 0, ErrTimeout
 			}
-			if d.wtTimeout == 0 {
-				// if there hasn't been a scheduled broadcast
-				time.AfterFunc(delta, d.rwCond.Broadcast)
-			}
-		}
-		if d.wtTimeout != 0 {
-			d.rDeadline = time.Now().Add(d.wtTimeout)
-			time.AfterFunc(d.wtTimeout, d.rwCond.Broadcast)
 		}
 
 		if len(d.pLens) > 0 {
@@ -100,6 +98,15 @@ func (d *datagramBufferedPipe) WriteTo(w io.Writer) (n int64, err error) {
 			}
 			d.rwCond.Broadcast()
 		} else {
+			if d.wtTimeout == 0 {
+				if hasRDeadline {
+					d.broadcastAfter(time.Until(d.rDeadline))
+				}
+			} else {
+				d.rDeadline = time.Now().Add(d.wtTimeout)
+				d.broadcastAfter(d.wtTimeout)
+			}
+
 			d.rwCond.Wait()
 		}
 	}
@@ -160,3 +167,10 @@ func (d *datagramBufferedPipe) SetWriteToTimeout(t time.Duration) {
 	d.wtTimeout = t
 	d.rwCond.Broadcast()
 }
+
+func (d *datagramBufferedPipe) broadcastAfter(t time.Duration) {
+	if d.timeoutTimer != nil {
+		d.timeoutTimer.Stop()
+	}
+	d.timeoutTimer = time.AfterFunc(t, d.rwCond.Broadcast)
+}

internal/multiplex/streamBufferedPipe.go

@@ -18,6 +18,8 @@ type streamBufferedPipe struct {
 	rwCond    *sync.Cond
 	rDeadline time.Time
 	wtTimeout time.Duration
+
+	timeoutTimer *time.Timer
 }
 
 func NewStreamBufferedPipe() *streamBufferedPipe {
@@ -37,16 +39,20 @@ func (p *streamBufferedPipe) Read(target []byte) (int, error) {
 		if p.closed && p.buf.Len() == 0 {
 			return 0, io.EOF
 		}
-		if !p.rDeadline.IsZero() {
-			d := time.Until(p.rDeadline)
-			if d <= 0 {
+
+		hasRDeadline := !p.rDeadline.IsZero()
+		if hasRDeadline {
+			if time.Until(p.rDeadline) <= 0 {
 				return 0, ErrTimeout
 			}
-			time.AfterFunc(d, p.rwCond.Broadcast)
 		}
 		if p.buf.Len() > 0 {
 			break
 		}
+
+		if hasRDeadline {
+			p.broadcastAfter(time.Until(p.rDeadline))
+		}
 		p.rwCond.Wait()
 	}
 	n, err := p.buf.Read(target)
@@ -65,19 +71,12 @@ func (p *streamBufferedPipe) WriteTo(w io.Writer) (n int64, err error) {
 		if p.closed && p.buf.Len() == 0 {
 			return 0, io.EOF
 		}
-		if !p.rDeadline.IsZero() {
-			d := time.Until(p.rDeadline)
-			if d <= 0 {
+
+		hasRDeadline := !p.rDeadline.IsZero()
+		if hasRDeadline {
+			if time.Until(p.rDeadline) <= 0 {
 				return 0, ErrTimeout
 			}
-			if p.wtTimeout == 0 {
-				// if there hasn't been a scheduled broadcast
-				time.AfterFunc(d, p.rwCond.Broadcast)
-			}
-		}
-		if p.wtTimeout != 0 {
-			p.rDeadline = time.Now().Add(p.wtTimeout)
-			time.AfterFunc(p.wtTimeout, p.rwCond.Broadcast)
 		}
 		if p.buf.Len() > 0 {
 			written, er := p.buf.WriteTo(w)
@@ -88,6 +87,15 @@ func (p *streamBufferedPipe) WriteTo(w io.Writer) (n int64, err error) {
 			}
 			p.rwCond.Broadcast()
 		} else {
+			if p.wtTimeout == 0 {
+				if hasRDeadline {
+					p.broadcastAfter(time.Until(p.rDeadline))
+				}
+			} else {
+				p.rDeadline = time.Now().Add(p.wtTimeout)
+				p.broadcastAfter(p.wtTimeout)
+			}
+
 			p.rwCond.Wait()
 		}
 	}
@@ -139,3 +147,10 @@ func (p *streamBufferedPipe) SetWriteToTimeout(d time.Duration) {
 	p.wtTimeout = d
 	p.rwCond.Broadcast()
 }
+
+func (p *streamBufferedPipe) broadcastAfter(d time.Duration) {
+	if p.timeoutTimer != nil {
+		p.timeoutTimer.Stop()
+	}
+	p.timeoutTimer = time.AfterFunc(d, p.rwCond.Broadcast)
+}