This repository has been archived by the owner on Apr 23, 2020. It is now read-only.
/
select.go
84 lines (75 loc) · 1.54 KB
/
select.go
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
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
package selector
import "reflect"
type Selector struct {
cases []reflect.SelectCase
selecting []reflect.SelectCase
toSend []func() interface{}
cbs []interface{}
}
type Case struct {
index int
selector *Selector
disabled bool
}
func New() *Selector {
return &Selector{}
}
var emptyCase = reflect.SelectCase{
Dir: reflect.SelectRecv,
}
func (s *Selector) Add(ch interface{}, cb interface{}, toSend func() interface{}) *Case {
dir := reflect.SelectRecv
if toSend != nil {
dir = reflect.SelectSend
}
selectCase := reflect.SelectCase{
Dir: dir,
Chan: reflect.ValueOf(ch),
}
s.cases = append(s.cases, selectCase)
s.selecting = append(s.selecting, selectCase)
s.toSend = append(s.toSend, toSend)
s.cbs = append(s.cbs, cb)
return &Case{
index: len(s.cases) - 1,
selector: s,
}
}
func (s *Selector) Select() {
for i, send := range s.toSend {
if send != nil {
s.selecting[i].Send = reflect.ValueOf(send())
}
}
n, recv, ok := reflect.Select(s.selecting)
if s.selecting[n].Dir == reflect.SelectRecv {
if ok {
if s.cbs[n] != nil {
switch cb := s.cbs[n].(type) {
case func():
cb()
case func(interface{}):
cb(recv.Interface())
default:
panic("unknown callback")
}
}
}
} else {
if s.cbs[n] != nil {
(s.cbs[n].(func()))()
}
}
}
func (c *Case) Disable() {
if !c.disabled {
c.selector.selecting[c.index] = emptyCase
c.disabled = true
}
}
func (c *Case) Enable() {
if c.disabled {
c.selector.selecting[c.index] = c.selector.cases[c.index]
c.disabled = false
}
}