gotosocial/vendor/codeberg.org/gruf/go-errors/once.go
2021-11-13 12:29:08 +01:00

45 lines
747 B
Go

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)
}