Use atomic.Value for Var state

1 files changed, 7 insertions, 14 deletions

diff --git a/var.go b/var.go
index 51160e2..4859643 100644
--- a/var.go
+++ b/var.go
@@ -3,27 +3,22 @@ package stm
 import (
 	"sync"
 	"sync/atomic"
-	"unsafe"
 )
 
 // Holds an STM variable.
 type Var struct {
-	state    *varSnapshot
+	state    atomic.Value
 	watchers sync.Map
 	mu       sync.Mutex
 }
 
-func (v *Var) addr() *unsafe.Pointer {
-	return (*unsafe.Pointer)(unsafe.Pointer(&v.state))
-}
-
-func (v *Var) loadState() *varSnapshot {
-	return (*varSnapshot)(atomic.LoadPointer(v.addr()))
+func (v *Var) loadState() varSnapshot {
+	return v.state.Load().(varSnapshot)
 }
 
 func (v *Var) changeValue(new interface{}) {
 	version := v.loadState().version
-	atomic.StorePointer(v.addr(), unsafe.Pointer(&varSnapshot{version: version + 1, val: new}))
+	v.state.Store(varSnapshot{version: version + 1, val: new})
 }
 
 type varSnapshot struct {
@@ -33,9 +28,7 @@ type varSnapshot struct {
 
 // Returns a new STM variable.
 func NewVar(val interface{}) *Var {
-	return &Var{
-		state: &varSnapshot{
-			val: val,
-		},
-	}
+	v := &Var{}
+	v.state.Store(varSnapshot{version: 0, val: val})
+	return v
 }