internal/gamepad: simplify the implementation by making the APIs concurrent-unsafe

internal/gamepad/gamepad.go

@@ -39,7 +39,6 @@ const (
 
 type gamepads struct {
 	gamepads []*Gamepad
-	m        sync.Mutex
 
 	nativeGamepads
 }
@@ -51,14 +50,17 @@ func init() {
 	theGamepads.nativeGamepads.gamepads = &theGamepads
 }
 
+// AppendGamepadIDs must be called on the main thread.
 func AppendGamepadIDs(ids []driver.GamepadID) []driver.GamepadID {
 	return theGamepads.appendGamepadIDs(ids)
 }
 
+// Update must be called on the main thread.
 func Update() {
 	theGamepads.update()
 }
 
+// Get must be called on the main thread.
 func Get(id driver.GamepadID) *Gamepad {
 	return theGamepads.get(id)
 }
@@ -73,9 +75,6 @@ func (g *gamepads) appendGamepadIDs(ids []driver.GamepadID) []driver.GamepadID {
 }
 
 func (g *gamepads) update() {
-	g.m.Lock()
-	defer g.m.Unlock()
-
 	g.nativeGamepads.update()
 	for _, gp := range g.gamepads {
 		if gp != nil {
@@ -85,12 +84,6 @@ func (g *gamepads) update() {
 }
 
 func (g *gamepads) get(id driver.GamepadID) *Gamepad {
-	g.m.Lock()
-	defer g.m.Unlock()
-	return g.getImpl(id)
-}
-
-func (g *gamepads) getImpl(id driver.GamepadID) *Gamepad {
 	if id < 0 || int(id) >= len(g.gamepads) {
 		return nil
 	}
@@ -98,12 +91,6 @@ func (g *gamepads) getImpl(id driver.GamepadID) *Gamepad {
 }
 
 func (g *gamepads) find(cond func(*Gamepad) bool) *Gamepad {
-	g.m.Lock()
-	defer g.m.Unlock()
-	return g.findImpl(cond)
-}
-
-func (g *gamepads) findImpl(cond func(*Gamepad) bool) *Gamepad {
 	for _, gp := range g.gamepads {
 		if gp == nil {
 			continue
@@ -116,12 +103,6 @@ func (g *gamepads) findImpl(cond func(*Gamepad) bool) *Gamepad {
 }
 
 func (g *gamepads) add(name, sdlID string) *Gamepad {
-	g.m.Lock()
-	defer g.m.Unlock()
-	return g.addImpl(name, sdlID)
-}
-
-func (g *gamepads) addImpl(name, sdlID string) *Gamepad {
 	for i, gp := range g.gamepads {
 		if gp == nil {
 			gp := &Gamepad{
@@ -142,12 +123,6 @@ func (g *gamepads) addImpl(name, sdlID string) *Gamepad {
 }
 
 func (g *gamepads) remove(cond func(*Gamepad) bool) {
-	g.m.Lock()
-	defer g.m.Unlock()
-	g.removeImpl(cond)
-}
-
-func (g *gamepads) removeImpl(cond func(*Gamepad) bool) {
 	for i, gp := range g.gamepads {
 		if gp == nil {
 			continue

internal/gamepad/gamepad_js.go

@@ -67,7 +67,7 @@ func (g *nativeGamepads) update() {
 		g.indices[index] = struct{}{}
 
 		// The gamepad is not registered yet, register this.
-		gamepad := g.gamepads.findImpl(func(gamepad *Gamepad) bool {
+		gamepad := g.gamepads.find(func(gamepad *Gamepad) bool {
 			return index == gamepad.index
 		})
 		if gamepad == nil {
@@ -78,7 +78,7 @@ func (g *nativeGamepads) update() {
 			var sdlID [16]byte
 			copy(sdlID[:], []byte(name))
 
-			gamepad = g.gamepads.addImpl(name, hex.EncodeToString(sdlID[:]))
+			gamepad = g.gamepads.add(name, hex.EncodeToString(sdlID[:]))
 			gamepad.index = index
 			gamepad.mapping = gp.Get("mapping").String()
 		}
@@ -86,7 +86,7 @@ func (g *nativeGamepads) update() {
 	}
 
 	// Remove an unused gamepads.
-	g.gamepads.removeImpl(func(gamepad *Gamepad) bool {
+	g.gamepads.remove(func(gamepad *Gamepad) bool {
 		_, ok := g.indices[gamepad.index]
 		return !ok
 	})

internal/uidriver/glfw/gamepad_native.go

@@ -26,16 +26,29 @@ import (
 
 type nativeGamepads struct{}
 
+// updateGamepads must be called on the main thread.
 func (i *Input) updateGamepads() {
 	gamepadpkg.Update()
 }
 
 func (i *Input) AppendGamepadIDs(gamepadIDs []driver.GamepadID) []driver.GamepadID {
-	return gamepadpkg.AppendGamepadIDs(gamepadIDs)
+	var gs []driver.GamepadID
+	i.ui.t.Call(func() {
+		gs = gamepadpkg.AppendGamepadIDs(gamepadIDs)
+	})
+	return gs
+}
+
+func (i *Input) gamepad(id driver.GamepadID) *gamepadpkg.Gamepad {
+	var g *gamepadpkg.Gamepad
+	i.ui.t.Call(func() {
+		g = gamepadpkg.Get(id)
+	})
+	return g
 }
 
 func (i *Input) GamepadSDLID(id driver.GamepadID) string {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return ""
 	}
@@ -43,7 +56,7 @@ func (i *Input) GamepadSDLID(id driver.GamepadID) string {
 }
 
 func (i *Input) GamepadName(id driver.GamepadID) string {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return ""
 	}
@@ -51,7 +64,7 @@ func (i *Input) GamepadName(id driver.GamepadID) string {
 }
 
 func (i *Input) GamepadAxisNum(id driver.GamepadID) int {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return 0
 	}
@@ -59,7 +72,7 @@ func (i *Input) GamepadAxisNum(id driver.GamepadID) int {
 }
 
 func (i *Input) GamepadAxisValue(id driver.GamepadID, axis int) float64 {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return 0
 	}
@@ -67,7 +80,7 @@ func (i *Input) GamepadAxisValue(id driver.GamepadID, axis int) float64 {
 }
 
 func (i *Input) GamepadButtonNum(id driver.GamepadID) int {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return 0
 	}
@@ -77,7 +90,7 @@ func (i *Input) GamepadButtonNum(id driver.GamepadID) int {
 }
 
 func (i *Input) IsGamepadButtonPressed(id driver.GamepadID, button driver.GamepadButton) bool {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return false
 	}
@@ -97,7 +110,7 @@ func (i *Input) IsGamepadButtonPressed(id driver.GamepadID, button driver.Gamepa
 }
 
 func (i *Input) IsStandardGamepadLayoutAvailable(id driver.GamepadID) bool {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return false
 	}
@@ -105,7 +118,7 @@ func (i *Input) IsStandardGamepadLayoutAvailable(id driver.GamepadID) bool {
 }
 
 func (i *Input) StandardGamepadAxisValue(id driver.GamepadID, axis driver.StandardGamepadAxis) float64 {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return 0
 	}
@@ -113,7 +126,7 @@ func (i *Input) StandardGamepadAxisValue(id driver.GamepadID, axis driver.Standa
 }
 
 func (i *Input) StandardGamepadButtonValue(id driver.GamepadID, button driver.StandardGamepadButton) float64 {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return 0
 	}
@@ -121,7 +134,7 @@ func (i *Input) StandardGamepadButtonValue(id driver.GamepadID, button driver.St
 }
 
 func (i *Input) IsStandardGamepadButtonPressed(id driver.GamepadID, button driver.StandardGamepadButton) bool {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return false
 	}
@@ -129,7 +142,7 @@ func (i *Input) IsStandardGamepadButtonPressed(id driver.GamepadID, button drive
 }
 
 func (i *Input) VibrateGamepad(id driver.GamepadID, duration time.Duration, strongMagnitude float64, weakMagnitude float64) {
-	g := gamepadpkg.Get(id)
+	g := i.gamepad(id)
 	if g == nil {
 		return
 	}