Recover gamepad state when add events are missed

app/streaming/input/gamepad.cpp

@@ -63,6 +63,40 @@ SdlInputHandler::findStateForGamepad(SDL_JoystickID id)
     return nullptr;
 }
 
+GamepadState*
+SdlInputHandler::ensureStateForGamepad(SDL_JoystickID id)
+{
+    GamepadState* state = findStateForGamepad(id);
+    if (state != nullptr) {
+        return state;
+    }
+
+    cleanupDetachedGamepads();
+
+    const int joystickCount = SDL_NumJoysticks();
+    for (int deviceIndex = 0; deviceIndex < joystickCount; deviceIndex++) {
+        if (!SDL_IsGameController(deviceIndex)) {
+            continue;
+        }
+
+        if (SDL_JoystickGetDeviceInstanceID(deviceIndex) != id) {
+            continue;
+        }
+
+        SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
+                    "Recovering gamepad state for missing add event (instance ID: %d)",
+                    id);
+
+        SDL_ControllerDeviceEvent controllerEvent = {};
+        controllerEvent.type = SDL_CONTROLLERDEVICEADDED;
+        controllerEvent.which = deviceIndex;
+        handleControllerDeviceEvent(&controllerEvent);
+        break;
+    }
+
+    return findStateForGamepad(id);
+}
+
 void SdlInputHandler::cleanupDetachedGamepads()
 {
     for (int i = 0; i < MAX_GAMEPADS; i++) {
@@ -226,7 +260,7 @@ Uint32 SdlInputHandler::mouseEmulationTimerCallback(Uint32 interval, void *param
 void SdlInputHandler::handleControllerAxisEvent(SDL_ControllerAxisEvent* event)
 {
     SDL_JoystickID gameControllerId = event->which;
-    GamepadState* state = findStateForGamepad(gameControllerId);
+    GamepadState* state = ensureStateForGamepad(gameControllerId);
     if (state == NULL) {
         return;
     }
@@ -296,7 +330,7 @@ void SdlInputHandler::handleControllerButtonEvent(SDL_ControllerButtonEvent* eve
         return;
     }
 
-    GamepadState* state = findStateForGamepad(event->which);
+    GamepadState* state = ensureStateForGamepad(event->which);
     if (state == NULL) {
         return;
     }
@@ -516,7 +550,7 @@ void SdlInputHandler::handleControllerButtonEvent(SDL_ControllerButtonEvent* eve
 
 void SdlInputHandler::handleControllerSensorEvent(SDL_ControllerSensorEvent* event)
 {
-    GamepadState* state = findStateForGamepad(event->which);
+    GamepadState* state = ensureStateForGamepad(event->which);
     if (state == NULL) {
         return;
     }
@@ -555,7 +589,7 @@ void SdlInputHandler::handleControllerSensorEvent(SDL_ControllerSensorEvent* eve
 
 void SdlInputHandler::handleControllerTouchpadEvent(SDL_ControllerTouchpadEvent* event)
 {
-    GamepadState* state = findStateForGamepad(event->which);
+    GamepadState* state = ensureStateForGamepad(event->which);
     if (state == NULL) {
         return;
     }
@@ -586,7 +620,7 @@ void SdlInputHandler::handleControllerTouchpadEvent(SDL_ControllerTouchpadEvent*
 
 void SdlInputHandler::handleJoystickBatteryEvent(SDL_JoyBatteryEvent* event)
 {
-    GamepadState* state = findStateForGamepad(event->which);
+    GamepadState* state = ensureStateForGamepad(event->which);
     if (state == NULL) {
         return;
     }

app/streaming/input/input.h

@@ -185,6 +185,9 @@ private:
     GamepadState*
     findStateForGamepad(SDL_JoystickID id);
 
+    GamepadState*
+    ensureStateForGamepad(SDL_JoystickID id);
+
     void cleanupDetachedGamepads();
 
     void sendGamepadState(GamepadState* state);