Wayland: Reconnect using the new approach using a new wl_display

In the case of a reconnect, application code is notified via
SDL_EVENT_RENDER_DEVICE_RESET.

src/events/SDL_mouse.c

@@ -292,14 +292,6 @@ SDL_Window *SDL_GetMouseFocus(void)
     return mouse->focus;
 }
 
-/* TODO RECONNECT: Hello from the Wayland video driver!
- * This was once removed from SDL, but it's been added back in comment form
- * because we will need it when Wayland adds compositor reconnect support.
- * If you need this before we do, great! Otherwise, leave this alone, we'll
- * uncomment it at the right time.
- * -flibit
- */
-#if 0
 void SDL_ResetMouse(void)
 {
     SDL_Mouse *mouse = SDL_GetMouse();
@@ -313,7 +305,6 @@ void SDL_ResetMouse(void)
     }
     SDL_assert(GetButtonState(mouse, SDL_FALSE) == 0);
 }
-#endif /* 0 */
 
 void SDL_SetMouseFocus(SDL_Window *window)
 {

src/events/SDL_mouse_c.h

@@ -158,10 +158,7 @@ extern int SDL_SendMouseWheel(Uint64 timestamp, SDL_Window *window, SDL_MouseID
 /* Warp the mouse within the window, potentially overriding relative mode */
 extern void SDL_PerformWarpMouseInWindow(SDL_Window *window, float x, float y, SDL_bool ignore_relative_mode);
 
-/* TODO RECONNECT: Set mouse state to "zero" */
-#if 0
 extern void SDL_ResetMouse(void);
-#endif /* 0 */
 
 /* Shutdown the mouse subsystem */
 extern void SDL_QuitMouse(void);

src/video/wayland/SDL_waylandevents.c

@@ -475,7 +475,14 @@ void Wayland_PumpEvents(SDL_VideoDevice *_this)
          *
          * Try to recover once, then quit.
          */
-        if (!Wayland_VideoReconnect(_this)) {
+        int errCode = WAYLAND_wl_display_get_error(d->display);
+        SDL_bool reconnected = SDL_FALSE;
+
+        if (SDL_getenv("SDL_VIDEO_WAYLAND_RECONNECT") && (errCode == EPIPE || errCode == ECONNRESET)) {
+            reconnected = Wayland_VideoReconnect(_this);
+        }
+
+        if (!reconnected) {
             d->display_disconnected = 1;
 
             /* Only send a single quit message, as application shutdown might call

src/video/wayland/SDL_waylandmouse.c

@@ -696,7 +696,6 @@ static Uint32 SDLCALL Wayland_GetGlobalMouseState(float *x, float *y)
     return ret;
 }
 
-#if 0  /* TODO RECONNECT: See waylandvideo.c for more information! */
 static void Wayland_RecreateCursor(SDL_Cursor *cursor, SDL_VideoData *vdata)
 {
     Wayland_CursorData *cdata = (Wayland_CursorData *) cursor->driverdata;
@@ -750,7 +749,6 @@ void Wayland_RecreateCursors(void)
         }
     }
 }
-#endif /* 0 */
 
 void Wayland_InitMouse(void)
 {

src/video/wayland/SDL_waylandmouse.h

@@ -26,8 +26,6 @@
 
 extern void Wayland_InitMouse(void);
 extern void Wayland_FiniMouse(SDL_VideoData *data);
-#if 0  /* TODO RECONNECT: See waylandvideo.c for more information! */
 extern void Wayland_RecreateCursors(void);
-#endif /* 0 */
 
 #endif

src/video/wayland/SDL_waylandvideo.c

@@ -888,7 +888,9 @@ int Wayland_VideoInit(SDL_VideoDevice *_this)
     wl_registry_add_listener(data->registry, &registry_listener, data);
 
     // First roundtrip to receive all registry objects.
-    WAYLAND_wl_display_roundtrip(data->display);
+    if (WAYLAND_wl_display_roundtrip(data->display) < 0) {
+        return SDL_SetError("Failed to load Wayland initial globals");
+    }
 
     /* Now that we have all the protocols, load libdecor if applicable */
     Wayland_LoadLibdecor(data, SDL_FALSE);
@@ -1047,49 +1049,72 @@ static void Wayland_VideoCleanup(SDL_VideoDevice *_this)
 
 SDL_bool Wayland_VideoReconnect(SDL_VideoDevice *_this)
 {
-#if 0 /* TODO RECONNECT: Uncomment all when https://invent.kde.org/plasma/kwin/-/wikis/Restarting is completed */
     SDL_VideoData *data = _this->driverdata;
-
     SDL_Window *window = NULL;
 
-    SDL_GLContext current_ctx = SDL_GL_GetCurrentContext();
-    SDL_Window *current_window = SDL_GL_GetCurrentWindow();
+    struct wl_display *new_display = WAYLAND_wl_display_connect(NULL);
+    struct wl_display *old_display = data->display;
+
+    SDL_Event event;
+
+    if (!new_display) {
+        return SDL_FALSE;
+    }
+    if (WAYLAND_wl_display_roundtrip(new_display) < 0) {
+        WAYLAND_wl_display_disconnect(new_display);
+        return SDL_FALSE;
+    }
 
     SDL_GL_MakeCurrent(NULL, NULL);
+
     Wayland_VideoCleanup(_this);
 
+    window = _this->windows;
+    while (window) {
+        SDL_free(window->outputs);
+        window->outputs = NULL;
+        window = window->next;
+    }
+
     SDL_ResetKeyboard();
     SDL_ResetMouse();
-    if (WAYLAND_wl_display_reconnect(data->display) < 0) {
+
+    data->display = new_display;
+    data->initializing = SDL_TRUE;
+
+    if (Wayland_VideoInit(_this) != 0) {
         return SDL_FALSE;
     }
 
-    Wayland_VideoInit(_this);
-
+/* When EGL supports migrating displays across connections we need to
+* enable the following code.
+*/
+#if 0
     window = _this->windows;
     while (window) {
-        /* We're going to cheat _just_ for a second and strip the OpenGL flag.
+        /*
+         * We're going to cheat _just_ for a second and strip the OpenGL flag.
          * The Wayland driver actually forces it in CreateWindow, and
          * RecreateWindow does a bunch of unloading/loading of libGL, so just
          * strip the flag so RecreateWindow doesn't mess with the GL context,
          * and CreateWindow will add it right back!
          * -flibit
+         *  window->flags &= ~SDL_WINDOW_OPENGL;
          */
-        window->flags &= ~SDL_WINDOW_OPENGL;
 
         SDL_RecreateWindow(window, window->flags);
         window = window->next;
     }
+#endif
+
+    event.type = SDL_EVENT_RENDER_DEVICE_RESET;
+    SDL_PushEvent(&event);
 
     Wayland_RecreateCursors();
 
-    if (current_window && current_ctx) {
-        SDL_GL_MakeCurrent (current_window, current_ctx);
-    }
+    WAYLAND_wl_display_disconnect(old_display);
+
     return SDL_TRUE;
-#else
-    return SDL_FALSE;
-#endif /* 0 */
 }
 
 void Wayland_VideoQuit(SDL_VideoDevice *_this)