forked from mirror/abool
98 lines
2.2 KiB
Go
98 lines
2.2 KiB
Go
// Package abool provides atomic Boolean type for cleaner code and
|
|
// better performance.
|
|
package abool
|
|
|
|
import (
|
|
"encoding/json"
|
|
"errors"
|
|
"fmt"
|
|
"sync/atomic"
|
|
)
|
|
|
|
// New creates an AtomicBool with default set to false.
|
|
func New() *AtomicBool {
|
|
return new(AtomicBool)
|
|
}
|
|
|
|
// NewBool creates an AtomicBool with given default value.
|
|
func NewBool(ok bool) *AtomicBool {
|
|
ab := New()
|
|
if ok {
|
|
ab.Set()
|
|
}
|
|
return ab
|
|
}
|
|
|
|
// AtomicBool is an atomic Boolean.
|
|
// Its methods are all atomic, thus safe to be called by multiple goroutines simultaneously.
|
|
// Note: When embedding into a struct one should always use *AtomicBool to avoid copy.
|
|
type AtomicBool int32
|
|
|
|
// Set sets the Boolean to true.
|
|
func (ab *AtomicBool) Set() {
|
|
atomic.StoreInt32((*int32)(ab), 1)
|
|
}
|
|
|
|
// UnSet sets the Boolean to false.
|
|
func (ab *AtomicBool) UnSet() {
|
|
atomic.StoreInt32((*int32)(ab), 0)
|
|
}
|
|
|
|
// IsSet returns whether the Boolean is true.
|
|
func (ab *AtomicBool) IsSet() bool {
|
|
return atomic.LoadInt32((*int32)(ab))&1 == 1
|
|
}
|
|
|
|
// IsNotSet returns whether the Boolean is false.
|
|
func (ab *AtomicBool) IsNotSet() bool {
|
|
return !ab.IsSet()
|
|
}
|
|
|
|
// SetTo sets the boolean with given Boolean.
|
|
func (ab *AtomicBool) SetTo(yes bool) {
|
|
if yes {
|
|
atomic.StoreInt32((*int32)(ab), 1)
|
|
} else {
|
|
atomic.StoreInt32((*int32)(ab), 0)
|
|
}
|
|
}
|
|
|
|
// Toggle inverts the Boolean then returns the value before inverting.
|
|
func (ab *AtomicBool) Toggle() bool {
|
|
return atomic.AddInt32((*int32)(ab), 1)&1 == 0
|
|
}
|
|
|
|
// SetToIf sets the Boolean to new only if the Boolean matches the old.
|
|
// Returns whether the set was done.
|
|
func (ab *AtomicBool) SetToIf(old, new bool) (set bool) {
|
|
var o, n int32
|
|
if old {
|
|
o = 1
|
|
}
|
|
if new {
|
|
n = 1
|
|
}
|
|
return atomic.CompareAndSwapInt32((*int32)(ab), o, n)
|
|
}
|
|
|
|
// Marshal an AtomicBool into JSON like a normal bool
|
|
func (ab *AtomicBool) MarshalJSON() ([]byte, error) {
|
|
return json.Marshal(ab.IsSet())
|
|
}
|
|
|
|
// Unmarshall normal bool's into AtomicBool
|
|
func (ab *AtomicBool) UnmarshalJSON(b []byte) error {
|
|
var v interface{}
|
|
if err := json.Unmarshal(b, &v); err != nil {
|
|
return err
|
|
}
|
|
|
|
switch value := v.(type) {
|
|
case bool:
|
|
ab.SetTo(value)
|
|
return nil
|
|
default:
|
|
return errors.New(fmt.Sprintf("%s is an invalid JSON representation for an AtomicBool\n", b))
|
|
}
|
|
}
|