bool: Generate with gen-valuewrapper

Generate atomic.Bool with gen-valuewrapper by wrapping atomic.Uint32.
CAS, Swap, and JSON implementations are generated automatically.

bool.go

@@ -1,3 +1,5 @@
+// @generated Code generated by gen-atomicwrapper.
+
 // Copyright (c) 2020 Uber Technologies, Inc.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -22,79 +24,58 @@ package atomic
 
 import (
 	"encoding/json"
-	"strconv"
-	"sync/atomic"
 )
 
-// Bool is an atomic Boolean.
+// Bool is an atomic type-safe wrapper for bool values.
 type Bool struct {
 	nocmp // disallow non-atomic comparison
 
-	v uint32
+	v Uint32
 }
 
-// NewBool creates a Bool.
-func NewBool(initial bool) *Bool {
-	return &Bool{v: boolToInt(initial)}
-}
+var _zeroBool bool
 
-// Load atomically loads the Boolean.
-func (b *Bool) Load() bool {
-	return truthy(atomic.LoadUint32(&b.v))
-}
-
-// CAS is an atomic compare-and-swap.
-func (b *Bool) CAS(old, new bool) bool {
-	return atomic.CompareAndSwapUint32(&b.v, boolToInt(old), boolToInt(new))
-}
-
-// Store atomically stores the passed value.
-func (b *Bool) Store(new bool) {
-	atomic.StoreUint32(&b.v, boolToInt(new))
-}
-
-// Swap sets the given value and returns the previous value.
-func (b *Bool) Swap(new bool) bool {
-	return truthy(atomic.SwapUint32(&b.v, boolToInt(new)))
-}
-
-// Toggle atomically negates the Boolean and returns the previous value.
-func (b *Bool) Toggle() bool {
-	for {
-		old := b.Load()
-		if b.CAS(old, !old) {
-			return old
-		}
+// NewBool creates a new Bool.
+func NewBool(v bool) *Bool {
+	x := &Bool{}
+	if v != _zeroBool {
+		x.Store(v)
 	}
+	return x
 }
 
-func truthy(n uint32) bool {
-	return n == 1
+// Load atomically loads the wrapped bool.
+func (x *Bool) Load() bool {
+	return truthy(x.v.Load())
 }
 
-func boolToInt(b bool) uint32 {
-	if b {
-		return 1
-	}
-	return 0
+// Store atomically stores the passed bool.
+func (x *Bool) Store(v bool) {
+	x.v.Store(boolToInt(v))
+}
+
+// CAS is an atomic compare-and-swap for bool values.
+func (x *Bool) CAS(o, n bool) bool {
+	return x.v.CAS(boolToInt(o), boolToInt(n))
+}
+
+// Swap atomically stores the given bool and returns the old
+// value.
+func (x *Bool) Swap(o bool) bool {
+	return truthy(x.v.Swap(boolToInt(o)))
 }
 
 // MarshalJSON encodes the wrapped bool into JSON.
-func (b *Bool) MarshalJSON() ([]byte, error) {
-	return json.Marshal(b.Load())
+func (x *Bool) MarshalJSON() ([]byte, error) {
+	return json.Marshal(x.Load())
 }
 
-// UnmarshalJSON decodes JSON into the wrapped bool.
-func (b *Bool) UnmarshalJSON(t []byte) error {
+// UnmarshalJSON decodes a bool from JSON.
+func (x *Bool) UnmarshalJSON(b []byte) error {
 	var v bool
-	if err := json.Unmarshal(t, &v); err != nil {
+	if err := json.Unmarshal(b, &v); err != nil {
 		return err
 	}
-	b.Store(v)
+	x.Store(v)
 	return nil
 }
-
-// String encodes the wrapped value as a string.
-func (b *Bool) String() string {
-	return strconv.FormatBool(b.Load())
-}

bool_ext.go

@@ -0,0 +1,53 @@
+// Copyright (c) 2020 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package atomic
+
+import (
+	"strconv"
+)
+
+//go:generate bin/gen-atomicwrapper -name=Bool -type=bool -wrapped=Uint32 -pack=boolToInt -unpack=truthy -cas -swap -json -file=bool.go
+
+func truthy(n uint32) bool {
+	return n == 1
+}
+
+func boolToInt(b bool) uint32 {
+	if b {
+		return 1
+	}
+	return 0
+}
+
+// Toggle atomically negates the Boolean and returns the previous value.
+func (b *Bool) Toggle() bool {
+	for {
+		old := b.Load()
+		if b.CAS(old, !old) {
+			return old
+		}
+	}
+}
+
+// String encodes the wrapped value as a string.
+func (b *Bool) String() string {
+	return strconv.FormatBool(b.Load())
+}