forked from mirror/abool
hide internal int32 data
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parent
7e73116d51
commit
00beeaa184
21
bool.go
21
bool.go
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@ -24,21 +24,23 @@ func NewBool(ok bool) *AtomicBool {
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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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type AtomicBool struct {
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boolean int32
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}
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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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atomic.StoreInt32((*int32)(&ab.boolean), 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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atomic.StoreInt32((*int32)(&ab.boolean), 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
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return atomic.LoadInt32((*int32)(&ab.boolean))&1 == 1
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}
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// IsNotSet returns whether the Boolean is false.
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@ -49,12 +51,17 @@ func (ab *AtomicBool) IsNotSet() bool {
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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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atomic.StoreInt32((*int32)(&ab.boolean), 1)
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} else {
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atomic.StoreInt32((*int32)(ab), 0)
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atomic.StoreInt32((*int32)(&ab.boolean), 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.boolean), 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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@ -65,7 +72,7 @@ func (ab *AtomicBool) SetToIf(old, new bool) (set bool) {
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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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return atomic.CompareAndSwapInt32((*int32)(&ab.boolean), o, n)
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}
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// MarshalJSON behaves the same as if the AtomicBool is a builtin.bool.
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67
bool_test.go
67
bool_test.go
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@ -2,6 +2,7 @@ package abool
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import (
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"encoding/json"
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"math"
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"sync"
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"sync/atomic"
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"testing"
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@ -72,6 +73,72 @@ func TestSetTo(t *testing.T) {
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}
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}
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func TestToggle(t *testing.T) {
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t.Parallel()
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v := New()
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_ = v.Toggle()
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if !v.IsSet() {
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t.Fatal("AtomicBool.Toggle() to true failed")
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}
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prev := v.Toggle()
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if v.IsSet() == prev {
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t.Fatal("AtomicBool.Toggle() to false failed")
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}
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}
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func TestToogleMultipleTimes(t *testing.T) {
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t.Parallel()
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v := New()
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pre := !v.IsSet()
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for i := 0; i < 100; i++ {
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v.SetTo(false)
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for j := 0; j < i; j++ {
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pre = v.Toggle()
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}
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expected := i%2 != 0
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if v.IsSet() != expected {
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t.Fatalf("AtomicBool.Toogle() doesn't work after %d calls, expected: %v, got %v", i, expected, v.IsSet())
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}
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if pre == v.IsSet() {
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t.Fatalf("AtomicBool.Toogle() returned wrong value at the %dth calls, expected: %v, got %v", i, !v.IsSet(), pre)
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}
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}
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}
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func TestToogleAfterOverflow(t *testing.T) {
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t.Parallel()
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var value int32 = math.MaxInt32
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v := &AtomicBool{value}
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valueBeforeToggle := v.boolean
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// test first toggle after overflow
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v.Toggle()
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expected := math.MaxInt32%2 == 0
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if v.IsSet() != expected {
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t.Fatalf("AtomicBool.Toogle() doesn't work after overflow, expected: %v, got %v", expected, v.IsSet())
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}
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// make sure overflow happened
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var valueAfterToggle int32 = v.boolean
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if valueAfterToggle >= valueBeforeToggle {
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t.Fatalf("Overflow does not happen as expected, before %d, after: %d", valueBeforeToggle, valueAfterToggle)
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}
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// test second toggle after overflow
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v.Toggle()
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expected = !expected
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if v.IsSet() != expected {
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t.Fatalf("AtomicBool.Toogle() doesn't work after the second call after overflow, expected: %v, got %v", expected, v.IsSet())
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}
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}
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func TestRace(t *testing.T) {
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repeat := 10000
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var wg sync.WaitGroup
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