- removed mutex operation, removed Toggle function as it is un-implem…

…entable using atomic operations on an uint32 value

core/atomic/flag.go

@@ -1,50 +1,34 @@
 package atomic
 
-import (
-	"sync"
-)
+import "sync/atomic"
 
 // Flag is an atomic flag
 type Flag struct {
-	mut   sync.RWMutex
-	value bool
+	value uint32
 }
 
 // SetReturningPrevious sets flag and returns its previous value
 func (flag *Flag) SetReturningPrevious() bool {
-	flag.mut.Lock()
-	previousValue := flag.value
-	flag.value = true
-	flag.mut.Unlock()
-
-	return previousValue
+	previousValue := atomic.SwapUint32(&flag.value, 1)
+	return previousValue == 1
 }
 
 // Reset resets the flag, putting it in off position
 func (flag *Flag) Reset() {
-	flag.mut.Lock()
-	flag.value = false
-	flag.mut.Unlock()
+	atomic.StoreUint32(&flag.value, 0)
 }
 
 // IsSet checks whether flag is set
 func (flag *Flag) IsSet() bool {
-	flag.mut.RLock()
-	defer flag.mut.RUnlock()
-
-	return flag.value
-}
-
-// Toggle toggles the flag
-func (flag *Flag) Toggle() {
-	flag.mut.Lock()
-	flag.value = !flag.value
-	flag.mut.Unlock()
+	value := atomic.LoadUint32(&flag.value)
+	return value == 1
 }
 
 // SetValue sets the new value in the flag
 func (flag *Flag) SetValue(newValue bool) {
-	flag.mut.Lock()
-	flag.value = newValue
-	flag.mut.Unlock()
+	if newValue {
+		_ = flag.SetReturningPrevious()
+	} else {
+		flag.Reset()
+	}
 }

core/atomic/flag_test.go

@@ -1,7 +1,6 @@
 package atomic
 
 import (
-	"github.com/stretchr/testify/assert"
 	"sync"
 	"testing"
 
@@ -95,25 +94,3 @@ func TestFlag_SetValue(t *testing.T) {
 	wg.Wait()
 	require.False(t, flag.IsSet())
 }
-
-func TestFlag_Toggle(t *testing.T) {
-	t.Parallel()
-
-	f := Flag{}
-	f.SetValue(true)
-
-	numToggles := 51
-	wg := sync.WaitGroup{}
-	wg.Add(numToggles)
-	for i := 0; i < numToggles; i++ {
-		go func() {
-			f.Toggle()
-
-			wg.Done()
-		}()
-	}
-
-	wg.Wait()
-
-	assert.False(t, f.IsSet())
-}