uidriver/glfw: Refactoring: Remove mutex from Input

Mixing a thread and a mutex is risky. Use a thread if possible.

internal/uidriver/glfw/input.go

@@ -47,8 +47,6 @@ type Input struct {
 	touches            map[int]pos // This is not updated until GLFW 3.3 is available (#417)
 	runeBuffer         []rune
 	ui                 *UserInterface
-
-	m sync.RWMutex
 }
 
 type pos struct {
@@ -57,82 +55,120 @@ type pos struct {
 }
 
 func (i *Input) CursorPosition() (x, y int) {
-	i.m.RLock()
-	cx, cy := i.cursorX, i.cursorY
-	i.m.RUnlock()
+	if !i.ui.isRunning() {
+		return 0, 0
+	}
+	var cx, cy int
+	_ = i.ui.t.Call(func() error {
+		cx, cy = i.cursorX, i.cursorY
+		return nil
+	})
 	return i.ui.adjustPosition(cx, cy)
 }
 
 func (i *Input) GamepadIDs() []int {
-	i.m.RLock()
-	defer i.m.RUnlock()
+	if !i.ui.isRunning() {
+		return nil
+	}
+	var r []int
+	_ = i.ui.t.Call(func() error {
 		if len(i.gamepads) == 0 {
 			return nil
 		}
-	r := []int{}
 		for id, g := range i.gamepads {
 			if g.valid {
 				r = append(r, id)
 			}
 		}
+		return nil
+	})
 	return r
 }
 
 func (i *Input) GamepadAxisNum(id int) int {
-	i.m.RLock()
-	defer i.m.RUnlock()
-	if len(i.gamepads) <= id {
+	if !i.ui.isRunning() {
 		return 0
 	}
-	return i.gamepads[id].axisNum
+	var r int
+	_ = i.ui.t.Call(func() error {
+		if len(i.gamepads) <= id {
+			return nil
+		}
+		r = i.gamepads[id].axisNum
+		return nil
+	})
+	return r
 }
 
 func (i *Input) GamepadAxis(id int, axis int) float64 {
-	i.m.RLock()
-	defer i.m.RUnlock()
-	if len(i.gamepads) <= id {
+	if !i.ui.isRunning() {
 		return 0
 	}
-	return i.gamepads[id].axes[axis]
+	var r float64
+	_ = i.ui.t.Call(func() error {
+		if len(i.gamepads) <= id {
+			return nil
+		}
+		r = i.gamepads[id].axes[axis]
+		return nil
+	})
+	return r
 }
 
 func (i *Input) GamepadButtonNum(id int) int {
-	i.m.RLock()
-	defer i.m.RUnlock()
-	if len(i.gamepads) <= id {
+	if !i.ui.isRunning() {
 		return 0
 	}
-	return i.gamepads[id].buttonNum
+	var r int
+	_ = i.ui.t.Call(func() error {
+		if len(i.gamepads) <= id {
+			return nil
+		}
+		r = i.gamepads[id].buttonNum
+		return nil
+	})
+	return r
 }
 
 func (i *Input) IsGamepadButtonPressed(id int, button driver.GamepadButton) bool {
-	i.m.RLock()
-	defer i.m.RUnlock()
-	if len(i.gamepads) <= id {
+	if !i.ui.isRunning() {
 		return false
 	}
-	return i.gamepads[id].buttonPressed[button]
+	var r bool
+	_ = i.ui.t.Call(func() error {
+		if len(i.gamepads) <= id {
+			return nil
+		}
+		r = i.gamepads[id].buttonPressed[button]
+		return nil
+	})
+	return r
 }
 
 func (i *Input) TouchIDs() []int {
-	i.m.RLock()
-	defer i.m.RUnlock()
-
+	if !i.ui.isRunning() {
+		return nil
+	}
+	var ids []int
+	_ = i.ui.t.Call(func() error {
 		if len(i.touches) == 0 {
 			return nil
 		}
-
-	var ids []int
 		for id := range i.touches {
 			ids = append(ids, id)
 		}
+		return nil
+	})
 	return ids
 }
 
 func (i *Input) TouchPosition(id int) (x, y int) {
-	i.m.RLock()
-	found := false
+	if !i.ui.isRunning() {
+		return 0, 0
+	}
+	var found bool
 	var p pos
+	_ = i.ui.t.Call(func() error {
 		for tid, pos := range i.touches {
 			if id == tid {
 				p = pos
@@ -140,8 +176,8 @@ func (i *Input) TouchPosition(id int) (x, y int) {
 				break
 			}
 		}
-	i.m.RUnlock()
-
+		return nil
+	})
 	if !found {
 		return 0, 0
 	}
@@ -149,21 +185,34 @@ func (i *Input) TouchPosition(id int) (x, y int) {
 }
 
 func (i *Input) RuneBuffer() []rune {
-	i.m.RLock()
-	defer i.m.RUnlock()
-	return i.runeBuffer
+	if !i.ui.isRunning() {
+		return nil
+	}
+	var r []rune
+	_ = i.ui.t.Call(func() error {
+		r = i.runeBuffer
+		return nil
+	})
+	return r
 }
 
 func (i *Input) ResetForFrame() {
-	i.m.RLock()
-	defer i.m.RUnlock()
+	if !i.ui.isRunning() {
+		return
+	}
+	_ = i.ui.t.Call(func() error {
 		i.runeBuffer = i.runeBuffer[:0]
 		i.scrollX, i.scrollY = 0, 0
+		return nil
+	})
 }
 
 func (i *Input) IsKeyPressed(key driver.Key) bool {
-	i.m.RLock()
-	defer i.m.RUnlock()
+	if !i.ui.isRunning() {
+		return false
+	}
+	var r bool
+	_ = i.ui.t.Call(func() error {
 		if i.keyPressed == nil {
 			i.keyPressed = map[glfw.Key]bool{}
 		}
@@ -172,15 +221,21 @@ func (i *Input) IsKeyPressed(key driver.Key) bool {
 				continue
 			}
 			if i.keyPressed[gk] {
-			return true
+				r = true
+				return nil
 			}
 		}
-	return false
+		return nil
+	})
+	return r
 }
 
 func (i *Input) IsMouseButtonPressed(button driver.MouseButton) bool {
-	i.m.RLock()
-	defer i.m.RUnlock()
+	if !i.ui.isRunning() {
+		return false
+	}
+	var r bool
+	_ = i.ui.t.Call(func() error {
 		if i.mouseButtonPressed == nil {
 			i.mouseButtonPressed = map[glfw.MouseButton]bool{}
 		}
@@ -189,16 +244,24 @@ func (i *Input) IsMouseButtonPressed(button driver.MouseButton) bool {
 				continue
 			}
 			if i.mouseButtonPressed[gb] {
-			return true
+				r = true
+				return nil
 			}
 		}
-	return false
+		return nil
+	})
+	return r
 }
 
 func (i *Input) Wheel() (xoff, yoff float64) {
-	i.m.RLock()
-	defer i.m.RUnlock()
-	return i.scrollX, i.scrollY
+	if !i.ui.isRunning() {
+		return 0, 0
+	}
+	_ = i.ui.t.Call(func() error {
+		xoff, yoff = i.scrollX, i.scrollY
+		return nil
+	})
+	return
 }
 
 var glfwMouseButtonToMouseButton = map[glfw.MouseButton]driver.MouseButton{
@@ -208,25 +271,21 @@ var glfwMouseButtonToMouseButton = map[glfw.MouseButton]driver.MouseButton{
 }
 
 func (i *Input) appendRuneBuffer(char rune) {
+	// As this function is called from GLFW callbacks, the current thread is main.
 	if !unicode.IsPrint(char) {
 		return
 	}
-	i.m.Lock()
 	i.runeBuffer = append(i.runeBuffer, char)
-	i.m.Unlock()
 }
 
 func (i *Input) setWheel(xoff, yoff float64) {
-	i.m.Lock()
+	// As this function is called from GLFW callbacks, the current thread is main.
 	i.scrollX = xoff
 	i.scrollY = yoff
-	i.m.Unlock()
 }
 
 func (i *Input) update(window *glfw.Window) {
-	i.m.Lock()
-	defer i.m.Unlock()
-
+	_ = i.ui.t.Call(func() error {
 		i.onceCallback.Do(func() {
 			window.SetCharModsCallback(func(w *glfw.Window, char rune, mods glfw.ModifierKey) {
 				i.appendRuneBuffer(char)
@@ -276,4 +335,6 @@ func (i *Input) update(window *glfw.Window) {
 				i.gamepads[id].buttonPressed[b] = glfw.Action(buttons[b]) == glfw.Press
 			}
 		}
+		return nil
+	})
 }

internal/uidriver/glfw/ui.go

@@ -845,9 +845,10 @@ func (u *UserInterface) update(context driver.UIContext) error {
 
 	_ = u.t.Call(func() error {
 		glfw.PollEvents()
-
+		return nil
+	})
 	u.input.update(u.window)
-
+	_ = u.t.Call(func() error {
 		defer hooks.ResumeAudio()
 
 		for !u.isRunnableInBackground() && u.window.GetAttrib(glfw.Focused) == 0 {