sync/atomic: Actually call the load function

sync/atomic/generic.go

@@ -0,0 +1,38 @@
+package uatomic
+
+import "sync/atomic"
+
+// Atom is a generic wrapper for atomic.Value.
+type Atom[T comparable] struct {
+	value atomic.Value
+}
+
+type atomWrapper[T comparable] struct { value T }
+
+// CompareAndSwap executes the compare-and-swap operation for the Atom.
+func (atom *Atom[T]) CompareAndSwap(old, neww T) (swapped bool) {
+	return atom.value.CompareAndSwap(
+		atomWrapper[T] { value: old },
+		atomWrapper[T] { value: neww })
+}
+
+func (atom *Atom[T]) Load() T {
+	return castSafe[T](atom.value.Load())
+}
+
+func (atom *Atom[T]) Store(val T) {
+	atom.value.Store(val)
+}
+
+func (atom *Atom[T]) Swap(neww T) T {
+	return castSafe[T](atom.value.Swap(neww))
+}
+
+func castSafe[T comparable](value any) T {
+	var zero T
+	if value == nil {
+		return zero
+	} else {
+		return value.(T)
+	}
+}

sync/monitor.go

@@ -39,12 +39,12 @@ func (this *Monitor[T]) Borrow () (T, func ()) {
 // updated value. The intended use of this function is like this:
 //
 //   value, done := monitor.BorrowReturn()
-//   defer done(value)
-func (this *Monitor[T]) BorrowReturn () (T, func (T)) {
+//   defer done(&value)
+func (this *Monitor[T]) BorrowReturn () (T, func (*T)) {
 	this.mutex.Lock()
-	return this.value, func (value T) {
+	return this.value, func (value *T) {
 		defer this.mutex.Unlock()
-		this.value = value
+		this.value = *value
 	}
 }
 
@@ -86,12 +86,12 @@ func (this *RWMonitor[T]) Borrow () (T, func ()) {
 // updated value. The intended use of this function is like this:
 //
 //   value, done := monitor.BorrowReturn()
-//   defer done(value)
-func (this *RWMonitor[T]) BorrowReturn () (T, func (T)) {
+//   defer done(&value)
+func (this *RWMonitor[T]) BorrowReturn () (T, func (*T)) {
 	this.mutex.Lock()
-	return this.value, func (value T) {
+	return this.value, func (value *T) {
 		defer this.mutex.Unlock()
-		this.value = value
+		this.value = *value
 	}
 }
 

sync/monitor_test.go

@@ -13,8 +13,8 @@ func TestMonitor (test *testing.T) {
 	} ()
 	func () {
 		value, done := mon.BorrowReturn()
+		defer done(&value)
 		value += 3
-		defer done(value)
 	} ()
 	func () {
 		value, done := mon.Borrow()
@@ -56,8 +56,8 @@ func TestRWMonitor (test *testing.T) {
 	} ()
 	func () {
 		value, done := mon.BorrowReturn()
+		defer done(&value)
 		value += 3
-		defer done(value)
 	} ()
 	func () {
 		value, done := mon.RBorrow()