refactor: enhance keyboard auto-release functionality and key state management

internal/usbgadget/hid_keyboard.go

@@ -158,25 +158,27 @@ func (u *UsbGadget) SetOnKeysDownChange(f func(state KeysDownState)) {
 	u.onKeysDownChange = &f
 }
 
-func (u *UsbGadget) scheduleAutoRelease() {
+func (u *UsbGadget) scheduleAutoRelease(key byte) {
 	u.kbdAutoReleaseLock.Lock()
 	defer unlockWithLog(&u.kbdAutoReleaseLock, u.log, "autoRelease scheduled")
 
-	if u.kbdAutoReleaseTimer != nil {
+	if u.kbdAutoReleaseTimers[key] != nil {
-		u.kbdAutoReleaseTimer.Stop()
+		u.kbdAutoReleaseTimers[key].Stop()
 	}
 
-	u.kbdAutoReleaseTimer = time.AfterFunc(autoReleaseKeyboardInterval, func() {
+	u.kbdAutoReleaseTimers[key] = time.AfterFunc(autoReleaseKeyboardInterval, func() {
-		u.performAutoRelease()
+		u.performAutoRelease(key)
 	})
 }
 
-func (u *UsbGadget) cancelAutoRelease() {
+func (u *UsbGadget) cancelAutoRelease(key byte) {
 	u.kbdAutoReleaseLock.Lock()
 	defer unlockWithLog(&u.kbdAutoReleaseLock, u.log, "autoRelease cancelled")
 
-	if u.kbdAutoReleaseTimer != nil {
+	if timer := u.kbdAutoReleaseTimers[key]; timer != nil {
-		u.kbdAutoReleaseTimer.Stop()
+		timer.Stop()
+		u.kbdAutoReleaseTimers[key] = nil
+		delete(u.kbdAutoReleaseTimers, key)
 	}
 }
 
@@ -184,27 +186,35 @@ func (u *UsbGadget) DelayAutoRelease() {
 	u.kbdAutoReleaseLock.Lock()
 	defer unlockWithLog(&u.kbdAutoReleaseLock, u.log, "autoRelease delayed")
 
-	if u.kbdAutoReleaseTimer == nil {
+	if u.kbdAutoReleaseTimers == nil {
 		return
 	}
 
-	u.kbdAutoReleaseTimer.Reset(autoReleaseKeyboardInterval)
+	for _, timer := range u.kbdAutoReleaseTimers {
+		if timer != nil {
+			timer.Reset(autoReleaseKeyboardInterval)
+		}
+	}
 }
 
-func (u *UsbGadget) performAutoRelease() {
+func (u *UsbGadget) performAutoRelease(key byte) {
-	select {
-	case <-u.keyboardStateCtx.Done():
-		return
-	default:
-	}
-
 	u.kbdAutoReleaseLock.Lock()
 
-	key := u.kbdAutoReleaseLastKey
+	if u.kbdAutoReleaseTimers[key] == nil {
+		u.log.Warn().Uint8("key", key).Msg("autoRelease timer not found")
+		u.kbdAutoReleaseLock.Unlock()
+		return
+	}
+
+	u.kbdAutoReleaseTimers[key].Stop()
+	u.kbdAutoReleaseTimers[key] = nil
+	delete(u.kbdAutoReleaseTimers, key)
+	u.kbdAutoReleaseLock.Unlock()
 
 	// Skip if already released
 	state := u.GetKeysDownState()
 	alreadyReleased := true
+
 	for i := range state.Keys {
 		if state.Keys[i] == key {
 			alreadyReleased = false
@@ -216,10 +226,7 @@ func (u *UsbGadget) performAutoRelease() {
 		return
 	}
 
-	u.kbdAutoReleaseTimer = nil
+	u.keypressReport(key, false)
-	u.kbdAutoReleaseLock.Unlock()
-
-	u.keypressReport(key, false) // autoRelease the ket
 }
 
 func (u *UsbGadget) listenKeyboardEvents() {
@@ -311,7 +318,7 @@ func (u *UsbGadget) keyboardWriteHidFile(modifier byte, keys []byte) error {
 	return nil
 }
 
-func (u *UsbGadget) UpdateKeysDown(modifier byte, keys []byte) {
+func (u *UsbGadget) UpdateKeysDown(modifier byte, keys []byte) KeysDownState {
 	// if we just reported an error roll over, we should clear the keys
 	if keys[0] == hidErrorRollOver {
 		for i := range keys {
@@ -329,7 +336,7 @@ func (u *UsbGadget) UpdateKeysDown(modifier byte, keys []byte) {
 	if u.keysDownState.Modifier == state.Modifier &&
 		bytes.Equal(u.keysDownState.Keys, state.Keys) {
 		u.keyboardStateLock.Unlock()
-		return // No change in key down state
+		return state // No change in key down state
 	}
 
 	u.keysDownState = state
@@ -338,7 +345,7 @@ func (u *UsbGadget) UpdateKeysDown(modifier byte, keys []byte) {
 	if u.onKeysDownChange != nil {
 		(*u.onKeysDownChange)(state) // this enques to the outgoing hidrpc queue via usb.go → currentSession.enqueueKeysDownState(...)
 	}
-	return
+	return state
 }
 
 func (u *UsbGadget) KeyboardReport(modifier byte, keys []byte) error {
@@ -397,7 +404,7 @@ var KeyCodeToMaskMap = map[byte]byte{
 	RightSuper:   ModifierMaskRightSuper,
 }
 
-func (u *UsbGadget) keypressReport(key byte, press bool) error {
+func (u *UsbGadget) keypressReport(key byte, press bool) (KeysDownState, error) {
 	defer u.resetUserInputTime()
 
 	l := u.log.With().Uint8("key", key).Bool("press", press).Logger()
@@ -466,21 +473,20 @@ func (u *UsbGadget) keypressReport(key byte, press bool) error {
 	}
 
 	err := u.keyboardWriteHidFile(modifier, keys)
-	u.UpdateKeysDown(modifier, keys)
+	return u.UpdateKeysDown(modifier, keys), err
-	return err
 }
 
 func (u *UsbGadget) KeypressReport(key byte, press bool) error {
-	u.kbdAutoReleaseLock.Lock()
+	state, err := u.keypressReport(key, press)
-	u.kbdAutoReleaseLastKey = key
+	isRolledOver := state.Keys[0] == hidErrorRollOver
-	u.kbdAutoReleaseLock.Unlock()
 
-	if press {
+	if isRolledOver {
-		u.scheduleAutoRelease()
+		u.cancelAutoRelease(key)
+	} else if press {
+		u.scheduleAutoRelease(key)
 	} else {
-		u.cancelAutoRelease()
+		u.cancelAutoRelease(key)
 	}
 
-	err := u.keypressReport(key, press)
 	return err
 }

internal/usbgadget/usbgadget.go

@@ -69,8 +69,7 @@ type UsbGadget struct {
 	keysDownState KeysDownState // keyboard dynamic state (modifier keys and pressed keys)
 
 	kbdAutoReleaseLock   sync.Mutex
-	kbdAutoReleaseTimer   *time.Timer
+	kbdAutoReleaseTimers map[byte]*time.Timer
-	kbdAutoReleaseLastKey byte
 
 	keyboardStateLock   sync.Mutex
 	keyboardStateCtx    context.Context
@@ -136,6 +135,7 @@ func newUsbGadget(name string, configMap map[string]gadgetConfigItem, enabledDev
 		keyboardStateCancel:  keyboardCancel,
 		keyboardState:        0,
 		keysDownState:        KeysDownState{Modifier: 0, Keys: []byte{0, 0, 0, 0, 0, 0}}, // must be initialized to hidKeyBufferSize (6) zero bytes
+		kbdAutoReleaseTimers: make(map[byte]*time.Timer),
 		enabledDevices:       *enabledDevices,
 		lastUserInput:        time.Now(),
 		log:                  logger,
@@ -163,10 +163,10 @@ func (u *UsbGadget) Close() error {
 
 	// Stop auto-release timer
 	u.kbdAutoReleaseLock.Lock()
-	if u.kbdAutoReleaseTimer != nil {
+	for _, timer := range u.kbdAutoReleaseTimers {
-		u.kbdAutoReleaseTimer.Stop()
+		timer.Stop()
-		u.kbdAutoReleaseTimer = nil
 	}
+	u.kbdAutoReleaseTimers = make(map[byte]*time.Timer)
 	u.kbdAutoReleaseLock.Unlock()
 
 	// Close HID files