forked from mirror/abool
93 lines
2.3 KiB
Go
93 lines
2.3 KiB
Go
// Package abool provides atomic Boolean type for cleaner code and
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// better performance.
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package abool
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import (
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"encoding/json"
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"sync/atomic"
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)
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// New creates an AtomicBool with default set to false.
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func New() *AtomicBool {
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return new(AtomicBool)
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}
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// NewBool creates an AtomicBool with given default value.
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func NewBool(ok bool) *AtomicBool {
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ab := New()
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if ok {
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ab.Set()
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}
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return ab
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}
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// AtomicBool is an atomic Boolean.
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// Its methods are all atomic, thus safe to be called by multiple goroutines simultaneously.
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// Note: When embedding into a struct one should always use *AtomicBool to avoid copy.
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type AtomicBool int32
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// Set sets the Boolean to true.
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func (ab *AtomicBool) Set() {
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atomic.StoreInt32((*int32)(ab), 1)
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}
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// UnSet sets the Boolean to false.
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func (ab *AtomicBool) UnSet() {
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atomic.StoreInt32((*int32)(ab), 0)
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}
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// IsSet returns whether the Boolean is true.
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func (ab *AtomicBool) IsSet() bool {
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return atomic.LoadInt32((*int32)(ab))&1 == 1
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}
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// IsNotSet returns whether the Boolean is false.
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func (ab *AtomicBool) IsNotSet() bool {
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return !ab.IsSet()
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}
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// SetTo sets the boolean with given Boolean.
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func (ab *AtomicBool) SetTo(yes bool) {
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if yes {
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atomic.StoreInt32((*int32)(ab), 1)
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} else {
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atomic.StoreInt32((*int32)(ab), 0)
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}
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}
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// Toggle inverts the Boolean then returns the value before inverting.
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func (ab *AtomicBool) Toggle() bool {
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return atomic.AddInt32((*int32)(ab), 1)&1 == 0
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}
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// SetToIf sets the Boolean to new only if the Boolean matches the old.
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// Returns whether the set was done.
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func (ab *AtomicBool) SetToIf(old, new bool) (set bool) {
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var o, n int32
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if old {
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o = 1
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}
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if new {
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n = 1
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}
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return atomic.CompareAndSwapInt32((*int32)(ab), o, n)
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}
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// Marshall behaves the same as if the AtomicBool is a builtin.bool.
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// NOTE: There's no lock during the process, usually it shouldn't be called with other methods in parallel.
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func (ab *AtomicBool) MarshalJSON() ([]byte, error) {
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return json.Marshal(ab.IsSet())
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}
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// Unmarshall behaves the same as if the AtomicBool is a builtin.bool.
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// NOTE: There's no lock during the process, usually it shouldn't be called with other methods in parallel.
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func (ab *AtomicBool) UnmarshalJSON(b []byte) error {
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var v bool
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if err := json.Unmarshal(b, &v); err != nil {
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return err
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}
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ab.SetTo(v)
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return nil
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}
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