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authorRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
committerRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
commit8528da672cc093d4dd06732819abc1f7b6b5a46e (patch)
tree334be80d4a4c85b77db6f6fdb67cbf0528cba5f5 /src/time/tick.go
parent73bcb69f272cbf34ddcc9daa56427a8683b5a95d (diff)
downloadgo-8528da672cc093d4dd06732819abc1f7b6b5a46e.tar.gz
build: move package sources from src/pkg to src
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.
Diffstat (limited to 'src/time/tick.go')
-rw-r--r--src/time/tick.go56
1 files changed, 56 insertions, 0 deletions
diff --git a/src/time/tick.go b/src/time/tick.go
new file mode 100644
index 000000000..19007841e
--- /dev/null
+++ b/src/time/tick.go
@@ -0,0 +1,56 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package time
+
+import "errors"
+
+// A Ticker holds a channel that delivers `ticks' of a clock
+// at intervals.
+type Ticker struct {
+ C <-chan Time // The channel on which the ticks are delivered.
+ r runtimeTimer
+}
+
+// NewTicker returns a new Ticker containing a channel that will send the
+// time with a period specified by the duration argument.
+// It adjusts the intervals or drops ticks to make up for slow receivers.
+// The duration d must be greater than zero; if not, NewTicker will panic.
+// Stop the ticker to release associated resources.
+func NewTicker(d Duration) *Ticker {
+ if d <= 0 {
+ panic(errors.New("non-positive interval for NewTicker"))
+ }
+ // Give the channel a 1-element time buffer.
+ // If the client falls behind while reading, we drop ticks
+ // on the floor until the client catches up.
+ c := make(chan Time, 1)
+ t := &Ticker{
+ C: c,
+ r: runtimeTimer{
+ when: when(d),
+ period: int64(d),
+ f: sendTime,
+ arg: c,
+ },
+ }
+ startTimer(&t.r)
+ return t
+}
+
+// Stop turns off a ticker. After Stop, no more ticks will be sent.
+// Stop does not close the channel, to prevent a read from the channel succeeding
+// incorrectly.
+func (t *Ticker) Stop() {
+ stopTimer(&t.r)
+}
+
+// Tick is a convenience wrapper for NewTicker providing access to the ticking
+// channel only. Useful for clients that have no need to shut down the ticker.
+func Tick(d Duration) <-chan Time {
+ if d <= 0 {
+ return nil
+ }
+ return NewTicker(d).C
+}