1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
package events
import (
"fmt"
"sync"
)
// Channel provides a sink that can be listened on. The writer and channel
// listener must operate in separate goroutines.
//
// Consumers should listen on Channel.C until Closed is closed.
type Channel struct {
C chan Event
closed chan struct{}
once sync.Once
}
// NewChannel returns a channel. If buffer is zero, the channel is
// unbuffered.
func NewChannel(buffer int) *Channel {
return &Channel{
C: make(chan Event, buffer),
closed: make(chan struct{}),
}
}
// Done returns a channel that will always proceed once the sink is closed.
func (ch *Channel) Done() chan struct{} {
return ch.closed
}
// Write the event to the channel. Must be called in a separate goroutine from
// the listener.
func (ch *Channel) Write(event Event) error {
select {
case ch.C <- event:
return nil
case <-ch.closed:
return ErrSinkClosed
}
}
// Close the channel sink.
func (ch *Channel) Close() error {
ch.once.Do(func() {
close(ch.closed)
})
return nil
}
func (ch *Channel) String() string {
// Serialize a copy of the Channel that doesn't contain the sync.Once,
// to avoid a data race.
ch2 := map[string]interface{}{
"C": ch.C,
"closed": ch.closed,
}
return fmt.Sprint(ch2)
}
|
