blob: ba21ed695bc2b847f614631357b520e2c51fa691 (
plain)
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
|
package errors
import (
"sync/atomic"
"unsafe"
)
// OnceError is an error structure that supports safe multi-threaded
// usage and setting only once (until reset)
type OnceError struct {
err unsafe.Pointer
}
// NewOnce returns a new OnceError instance
func NewOnce() OnceError {
return OnceError{
err: nil,
}
}
func (e *OnceError) Store(err error) {
// Nothing to do
if err == nil {
return
}
// Only set if not already
atomic.CompareAndSwapPointer(
&e.err,
nil,
unsafe.Pointer(&err),
)
}
func (e *OnceError) Load() error {
return *(*error)(atomic.LoadPointer(&e.err))
}
func (e *OnceError) IsSet() bool {
return (atomic.LoadPointer(&e.err) != nil)
}
func (e *OnceError) Reset() {
atomic.StorePointer(&e.err, nil)
}
|
