Avoid allocating for each binding trigger

data/binding/binding.go

@@ -9,7 +9,6 @@ import (
 	"sync"
 
 	"fyne.io/fyne/v2"
-	"fyne.io/fyne/v2/internal/async"
 )
 
 var (
@@ -58,31 +57,38 @@ func (l *listener) DataChanged() {
 }
 
 type base struct {
-	listeners async.Map[DataListener, bool]
+	listeners []DataListener
 
 	lock sync.RWMutex
 }
 
 // AddListener allows a data listener to be informed of changes to this item.
 func (b *base) AddListener(l DataListener) {
-	b.listeners.Store(l, true)
-	queueItem(l.DataChanged)
+	queueItem(func() {
+		b.listeners = append(b.listeners, l)
+		l.DataChanged()
+	})
 }
 
 // RemoveListener should be called if the listener is no longer interested in being informed of data change events.
 func (b *base) RemoveListener(l DataListener) {
-	b.listeners.Delete(l)
+	queueItem(func() {
+		for i, listener := range b.listeners {
+			if listener == l {
+				// Delete without preserving order:
+				lastIndex := len(b.listeners) - 1
+				b.listeners[i] = b.listeners[lastIndex]
+				b.listeners[lastIndex] = nil
+				b.listeners = b.listeners[:lastIndex]
+				return
+			}
+		}
+	})
 }
 
 func (b *base) trigger() {
-	var listeners []DataListener
-	b.listeners.Range(func(listener DataListener, _ bool) bool {
-		listeners = append(listeners, listener)
-		return true
-	})
-
 	queueItem(func() {
-		for _, listen := range listeners {
+		for _, listen := range b.listeners {
 			listen.DataChanged()
 		}
 	})

data/binding/binding_test.go

@@ -12,14 +12,14 @@ type simpleItem struct {
 
 func TestBase_AddListener(t *testing.T) {
 	data := &simpleItem{}
-	assert.Equal(t, 0, data.listeners.Len())
+	assert.Equal(t, 0, len(data.listeners))
 
 	called := false
 	fn := NewDataListener(func() {
 		called = true
 	})
 	data.AddListener(fn)
-	assert.Equal(t, 1, data.listeners.Len())
+	assert.Equal(t, 1, len(data.listeners))
 	assert.True(t, called)
 }
 
@@ -29,11 +29,11 @@ func TestBase_RemoveListener(t *testing.T) {
 		called = true
 	})
 	data := &simpleItem{}
-	data.listeners.Store(fn, true)
+	data.listeners = append(data.listeners, fn)
 
-	assert.Equal(t, 1, data.listeners.Len())
+	assert.Equal(t, 1, len(data.listeners))
 	data.RemoveListener(fn)
-	assert.Equal(t, 0, data.listeners.Len())
+	assert.Equal(t, 0, len(data.listeners))
 
 	data.trigger()
 	assert.False(t, called)

data/binding/lists_test.go

@@ -12,14 +12,14 @@ type simpleList struct {
 
 func TestListBase_AddListener(t *testing.T) {
 	data := &simpleList{}
-	assert.Equal(t, 0, data.listeners.Len())
+	assert.Equal(t, 0, len(data.listeners))
 
 	called := false
 	fn := NewDataListener(func() {
 		called = true
 	})
 	data.AddListener(fn)
-	assert.Equal(t, 1, data.listeners.Len())
+	assert.Equal(t, 1, len(data.listeners))
 
 	data.trigger()
 	assert.True(t, called)
@@ -55,11 +55,11 @@ func TestListBase_RemoveListener(t *testing.T) {
 		called = true
 	})
 	data := &simpleList{}
-	data.listeners.Store(fn, true)
+	data.listeners = append(data.listeners, fn)
 
-	assert.Equal(t, 1, data.listeners.Len())
+	assert.Equal(t, 1, len(data.listeners))
 	data.RemoveListener(fn)
-	assert.Equal(t, 0, data.listeners.Len())
+	assert.Equal(t, 0, len(data.listeners))
 
 	data.trigger()
 	assert.False(t, called)

data/binding/trees_test.go

@@ -8,14 +8,14 @@ import (
 
 func TestTreeBase_AddListener(t *testing.T) {
 	data := newSimpleTree()
-	assert.Equal(t, 0, data.listeners.Len())
+	assert.Equal(t, 0, len(data.listeners))
 
 	called := false
 	fn := NewDataListener(func() {
 		called = true
 	})
 	data.AddListener(fn)
-	assert.Equal(t, 1, data.listeners.Len())
+	assert.Equal(t, 1, len(data.listeners))
 
 	data.trigger()
 	assert.True(t, called)
@@ -52,11 +52,11 @@ func TestTreeBase_RemoveListener(t *testing.T) {
 		called = true
 	})
 	data := newSimpleTree()
-	data.listeners.Store(fn, true)
+	data.listeners = append(data.listeners, fn)
 
-	assert.Equal(t, 1, data.listeners.Len())
+	assert.Equal(t, 1, len(data.listeners))
 	data.RemoveListener(fn)
-	assert.Equal(t, 0, data.listeners.Len())
+	assert.Equal(t, 0, len(data.listeners))
 
 	data.trigger()
 	assert.False(t, called)