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author | Russ Cox <rsc@golang.org> | 2014-09-08 00:08:51 -0400 |
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committer | Russ Cox <rsc@golang.org> | 2014-09-08 00:08:51 -0400 |
commit | 8528da672cc093d4dd06732819abc1f7b6b5a46e (patch) | |
tree | 334be80d4a4c85b77db6f6fdb67cbf0528cba5f5 /src/time/tick.go | |
parent | 73bcb69f272cbf34ddcc9daa56427a8683b5a95d (diff) | |
download | go-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.go | 56 |
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 +} |