Add property to ignore updates of same characteristic values #128 #166

If a characteristic value is updated with the same value, it is ignored.
Only exception is the programmable switch event characteristic, which
requires that clients are notified even when updating with the same value.

characteristic/characteristic.go

@@ -30,6 +30,7 @@ type Characteristic struct {
 	// unused
 	Events bool `json:"-"`
 
+	updateOnSameValue    bool // if true the update notifications
 	connValueUpdateFuncs []ConnChangeFunc
 	valueChangeFuncs     []ChangeFunc
 	valueGetFunc         GetFunc
@@ -124,8 +125,11 @@ func (c *Characteristic) updateValue(value interface{}, conn net.Conn, checkPerm
 		value = c.clampInt(value.(int))
 	}
 
+	if c.Value == value && !c.updateOnSameValue {
+		return
+	}
+
 	// Ignore new values from remote when permissions don't allow write and checkPerms is true
-	// Ignore value when not writable
 	if checkPerms && !c.isWritable() {
 		return
 	}

characteristic/characteristic_test.go

@@ -117,21 +117,32 @@ func TestCharacteristicRemoteDelegate(t *testing.T) {
 	}
 }
 
-func TestValueChange(t *testing.T) {
-	c := NewBrightness()
-	c.Value = 5
+func TestValueChangeNoUPdate(t *testing.T) {
+	c := NewOn()
+	c.Value = true
 
 	changed := false
-	c.OnValueUpdateFromConn(func(conn net.Conn, c *Characteristic, new, old interface{}) {
+	c.OnValueUpdate(func(c *Characteristic, new, old interface{}) {
 		changed = true
 	})
 
+	c.UpdateValue(true)
+
+	if is, want := changed, false; is != want {
+		t.Fatalf("%v != %v", is, want)
+	}
+}
+
+func TestValueChange(t *testing.T) {
+	c := NewProgrammableSwitchEvent()
+	c.Value = ProgrammableSwitchEventSinglePress
+
+	changed := false
 	c.OnValueUpdate(func(c *Characteristic, new, old interface{}) {
 		changed = true
 	})
 
-	c.UpdateValue(5)
-	c.UpdateValueFromConnection(5, TestConn)
+	c.UpdateValue(ProgrammableSwitchEventSinglePress)
 
 	if is, want := changed, true; is != want {
 		t.Fatalf("%v != %v", is, want)

characteristic/programmable_switch_event.go

@@ -20,5 +20,7 @@ func NewProgrammableSwitchEvent() *ProgrammableSwitchEvent {
 
 	char.SetValue(0)
 
+	char.updateOnSameValue = true
+
 	return &ProgrammableSwitchEvent{char}
 }