internal/gamepad: make the APIs concurrent-safe again

internal/gamepad/gamepad.go

@@ -40,6 +40,7 @@ const (
 type gamepads struct {
 	inited   bool
 	gamepads []*Gamepad
+	m        sync.Mutex
 
 	nativeGamepads
 }
@@ -50,22 +51,22 @@ 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)
 }
 
 func (g *gamepads) appendGamepadIDs(ids []driver.GamepadID) []driver.GamepadID {
+	g.m.Lock()
+	defer g.m.Unlock()
+
 	for i, gp := range g.gamepads {
 		if gp != nil && gp.present() {
 			ids = append(ids, driver.GamepadID(i))
@@ -75,6 +76,9 @@ func (g *gamepads) appendGamepadIDs(ids []driver.GamepadID) []driver.GamepadID {
 }
 
 func (g *gamepads) update() {
+	g.m.Lock()
+	defer g.m.Unlock()
+
 	if !g.inited {
 		g.nativeGamepads.init()
 		g.inited = true
@@ -89,14 +93,15 @@ func (g *gamepads) update() {
 }
 
 func (g *gamepads) get(id driver.GamepadID) *Gamepad {
+	g.m.Lock()
+	defer g.m.Unlock()
+
 	if id < 0 || int(id) >= len(g.gamepads) {
 		return nil
 	}
 	return g.gamepads[id]
 }
 
-// find can be invoked from callbacks on the OS's main thread.
-// As a callback can be called synchronously from update, using a mutex is not a good idea.
 func (g *gamepads) find(cond func(*Gamepad) bool) *Gamepad {
 	for _, gp := range g.gamepads {
 		if gp == nil {
@@ -109,8 +114,6 @@ func (g *gamepads) find(cond func(*Gamepad) bool) *Gamepad {
 	return nil
 }
 
-// add can be invoked from callbacks on the OS's main thread.
-// As a callback can be called synchronously from update, using a mutex is not a good idea.
 func (g *gamepads) add(name, sdlID string) *Gamepad {
 	for i, gp := range g.gamepads {
 		if gp == nil {
@@ -131,8 +134,6 @@ func (g *gamepads) add(name, sdlID string) *Gamepad {
 	return gp
 }
 
-// remove can be invoked from callbacks on the OS's main thread.
-// As a callback can be called synchronously from update, using a mutex is not a good idea.
 func (g *gamepads) remove(cond func(*Gamepad) bool) {
 	for i, gp := range g.gamepads {
 		if gp == nil {

internal/gamepad/gamepad_darwin.go

@@ -20,6 +20,7 @@ package gamepad
 import (
 	"fmt"
 	"sort"
+	"sync"
 	"time"
 	"unsafe"
 )
@@ -60,7 +61,10 @@ import "C"
 type nativeGamepads struct {
 	gamepads *gamepads
 
-	hidManager C.IOHIDManagerRef
+	hidManager      C.IOHIDManagerRef
+	devicesToAdd    []C.IOHIDDeviceRef
+	devicesToRemove []C.IOHIDDeviceRef
+	devicesM        sync.Mutex
 }
 
 type nativeGamepad struct {
@@ -285,7 +289,36 @@ func (g *nativeGamepads) init() {
 
 //export ebitenGamepadMatchingCallback
 func ebitenGamepadMatchingCallback(ctx unsafe.Pointer, res C.IOReturn, sender unsafe.Pointer, device C.IOHIDDeviceRef) {
-	if theGamepads.find(func(g *Gamepad) bool {
+	theGamepads.devicesM.Lock()
+	defer theGamepads.devicesM.Unlock()
+	theGamepads.devicesToAdd = append(theGamepads.devicesToAdd, device)
+}
+
+//export ebitenGamepadRemovalCallback
+func ebitenGamepadRemovalCallback(ctx unsafe.Pointer, res C.IOReturn, sender unsafe.Pointer, device C.IOHIDDeviceRef) {
+	theGamepads.devicesM.Lock()
+	defer theGamepads.devicesM.Unlock()
+	theGamepads.devicesToRemove = append(theGamepads.devicesToRemove, device)
+}
+
+func (g *nativeGamepads) update() {
+	theGamepads.devicesM.Lock()
+	defer theGamepads.devicesM.Unlock()
+
+	for _, device := range g.devicesToAdd {
+		g.addDevice(device)
+	}
+	for _, device := range g.devicesToRemove {
+		g.gamepads.remove(func(g *Gamepad) bool {
+			return g.device == device
+		})
+	}
+	g.devicesToAdd = g.devicesToAdd[:0]
+	g.devicesToRemove = g.devicesToRemove[:0]
+}
+
+func (g *nativeGamepads) addDevice(device C.IOHIDDeviceRef) {
+	if g.gamepads.find(func(g *Gamepad) bool {
 		return g.device == device
 	}) != nil {
 		return
@@ -331,8 +364,8 @@ func ebitenGamepadMatchingCallback(ctx unsafe.Pointer, res C.IOReturn, sender un
 	elements := C.IOHIDDeviceCopyMatchingElements(device, 0, C.kIOHIDOptionsTypeNone)
 	defer C.CFRelease(C.CFTypeRef(elements))
 
-	g := theGamepads.add(name, sdlID)
-	g.device = device
+	gp := g.gamepads.add(name, sdlID)
+	gp.device = device
 
 	for i := C.CFIndex(0); i < C.CFArrayGetCount(elements); i++ {
 		native := (C.IOHIDElementRef)(C.CFArrayGetValueAtIndex(elements, i))
@@ -356,27 +389,27 @@ func ebitenGamepadMatchingCallback(ctx unsafe.Pointer, res C.IOReturn, sender un
 			case C.kHIDUsage_GD_X, C.kHIDUsage_GD_Y, C.kHIDUsage_GD_Z,
 				C.kHIDUsage_GD_Rx, C.kHIDUsage_GD_Ry, C.kHIDUsage_GD_Rz,
 				C.kHIDUsage_GD_Slider, C.kHIDUsage_GD_Dial, C.kHIDUsage_GD_Wheel:
-				g.axes = append(g.axes, element{
+				gp.axes = append(gp.axes, element{
 					native:  native,
 					usage:   int(usage),
-					index:   len(g.axes),
+					index:   len(gp.axes),
 					minimum: int(C.IOHIDElementGetLogicalMin(native)),
 					maximum: int(C.IOHIDElementGetLogicalMax(native)),
 				})
 			case C.kHIDUsage_GD_Hatswitch:
-				g.hats = append(g.hats, element{
+				gp.hats = append(gp.hats, element{
 					native:  native,
 					usage:   int(usage),
-					index:   len(g.hats),
+					index:   len(gp.hats),
 					minimum: int(C.IOHIDElementGetLogicalMin(native)),
 					maximum: int(C.IOHIDElementGetLogicalMax(native)),
 				})
 			case C.kHIDUsage_GD_DPadUp, C.kHIDUsage_GD_DPadRight, C.kHIDUsage_GD_DPadDown, C.kHIDUsage_GD_DPadLeft,
 				C.kHIDUsage_GD_SystemMainMenu, C.kHIDUsage_GD_Select, C.kHIDUsage_GD_Start:
-				g.buttons = append(g.buttons, element{
+				gp.buttons = append(gp.buttons, element{
 					native:  native,
 					usage:   int(usage),
-					index:   len(g.buttons),
+					index:   len(gp.buttons),
 					minimum: int(C.IOHIDElementGetLogicalMin(native)),
 					maximum: int(C.IOHIDElementGetLogicalMax(native)),
 				})
@@ -384,36 +417,26 @@ func ebitenGamepadMatchingCallback(ctx unsafe.Pointer, res C.IOReturn, sender un
 		case C.kHIDPage_Simulation:
 			switch usage {
 			case C.kHIDUsage_Sim_Accelerator, C.kHIDUsage_Sim_Brake, C.kHIDUsage_Sim_Throttle, C.kHIDUsage_Sim_Rudder, C.kHIDUsage_Sim_Steering:
-				g.axes = append(g.axes, element{
+				gp.axes = append(gp.axes, element{
 					native:  native,
 					usage:   int(usage),
-					index:   len(g.axes),
+					index:   len(gp.axes),
 					minimum: int(C.IOHIDElementGetLogicalMin(native)),
 					maximum: int(C.IOHIDElementGetLogicalMax(native)),
 				})
 			}
 		case C.kHIDPage_Button, C.kHIDPage_Consumer:
-			g.buttons = append(g.buttons, element{
+			gp.buttons = append(gp.buttons, element{
 				native:  native,
 				usage:   int(usage),
-				index:   len(g.buttons),
+				index:   len(gp.buttons),
 				minimum: int(C.IOHIDElementGetLogicalMin(native)),
 				maximum: int(C.IOHIDElementGetLogicalMax(native)),
 			})
 		}
 	}
 
-	sort.Stable(g.axes)
-	sort.Stable(g.buttons)
-	sort.Stable(g.hats)
-}
-
-//export ebitenGamepadRemovalCallback
-func ebitenGamepadRemovalCallback(ctx unsafe.Pointer, res C.IOReturn, sender unsafe.Pointer, device C.IOHIDDeviceRef) {
-	theGamepads.remove(func(g *Gamepad) bool {
-		return g.device == device
-	})
-}
-
-func (g *nativeGamepads) update() {
+	sort.Stable(gp.axes)
+	sort.Stable(gp.buttons)
+	sort.Stable(gp.hats)
 }

internal/uidriver/glfw/gamepad_native.go

@@ -32,23 +32,11 @@ func (i *Input) updateGamepads() {
 }
 
 func (i *Input) AppendGamepadIDs(gamepadIDs []driver.GamepadID) []driver.GamepadID {
-	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
+	return gamepadpkg.AppendGamepadIDs(gamepadIDs)
 }
 
 func (i *Input) GamepadSDLID(id driver.GamepadID) string {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return ""
 	}
@@ -56,7 +44,7 @@ func (i *Input) GamepadSDLID(id driver.GamepadID) string {
 }
 
 func (i *Input) GamepadName(id driver.GamepadID) string {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return ""
 	}
@@ -64,7 +52,7 @@ func (i *Input) GamepadName(id driver.GamepadID) string {
 }
 
 func (i *Input) GamepadAxisNum(id driver.GamepadID) int {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return 0
 	}
@@ -72,7 +60,7 @@ func (i *Input) GamepadAxisNum(id driver.GamepadID) int {
 }
 
 func (i *Input) GamepadAxisValue(id driver.GamepadID, axis int) float64 {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return 0
 	}
@@ -80,7 +68,7 @@ func (i *Input) GamepadAxisValue(id driver.GamepadID, axis int) float64 {
 }
 
 func (i *Input) GamepadButtonNum(id driver.GamepadID) int {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return 0
 	}
@@ -90,7 +78,7 @@ func (i *Input) GamepadButtonNum(id driver.GamepadID) int {
 }
 
 func (i *Input) IsGamepadButtonPressed(id driver.GamepadID, button driver.GamepadButton) bool {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return false
 	}
@@ -110,7 +98,7 @@ func (i *Input) IsGamepadButtonPressed(id driver.GamepadID, button driver.Gamepa
 }
 
 func (i *Input) IsStandardGamepadLayoutAvailable(id driver.GamepadID) bool {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return false
 	}
@@ -118,7 +106,7 @@ func (i *Input) IsStandardGamepadLayoutAvailable(id driver.GamepadID) bool {
 }
 
 func (i *Input) StandardGamepadAxisValue(id driver.GamepadID, axis driver.StandardGamepadAxis) float64 {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return 0
 	}
@@ -126,7 +114,7 @@ func (i *Input) StandardGamepadAxisValue(id driver.GamepadID, axis driver.Standa
 }
 
 func (i *Input) StandardGamepadButtonValue(id driver.GamepadID, button driver.StandardGamepadButton) float64 {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return 0
 	}
@@ -134,7 +122,7 @@ func (i *Input) StandardGamepadButtonValue(id driver.GamepadID, button driver.St
 }
 
 func (i *Input) IsStandardGamepadButtonPressed(id driver.GamepadID, button driver.StandardGamepadButton) bool {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return false
 	}
@@ -142,7 +130,7 @@ func (i *Input) IsStandardGamepadButtonPressed(id driver.GamepadID, button drive
 }
 
 func (i *Input) VibrateGamepad(id driver.GamepadID, duration time.Duration, strongMagnitude float64, weakMagnitude float64) {
-	g := i.gamepad(id)
+	g := gamepadpkg.Get(id)
 	if g == nil {
 		return
 	}