[Wayland] Fixes segfault when mouse enters window

src/video/wayland/SDL_waylandevents.c

@@ -87,10 +87,19 @@ pointer_handle_enter(void *data, struct wl_pointer *pointer,
         return;
     }
     
-    input->pointer_focus = wl_surface_get_user_data(surface);
+    /* This handler will be called twice in Wayland 1.4
-    window = input->pointer_focus;
+     * Once for the window surface which has valid user data
+     * and again for the mouse cursor surface which does not have valid user data
+     * We ignore the later
+     */
+
+    window = (SDL_WindowData *)wl_surface_get_user_data(surface);
+    
+    if (window) {
+        input->pointer_focus = window;
         SDL_SetMouseFocus(window->sdlwindow);
     }
+}
 
 static void
 pointer_handle_leave(void *data, struct wl_pointer *pointer,
@@ -98,9 +107,11 @@ pointer_handle_leave(void *data, struct wl_pointer *pointer,
 {
     struct SDL_WaylandInput *input = data;
 
+    if (input->pointer_focus) {
         SDL_SetMouseFocus(NULL);
         input->pointer_focus = NULL;
     }
+}
 
 static void
 pointer_handle_motion(void *data, struct wl_pointer *pointer,
@@ -110,9 +121,10 @@ pointer_handle_motion(void *data, struct wl_pointer *pointer,
     SDL_WindowData *window = input->pointer_focus;
     int sx = wl_fixed_to_int(sx_w);
     int sy = wl_fixed_to_int(sy_w);
-
+    if (input->pointer_focus) {
         SDL_SendMouseMotion(window->sdlwindow, 0, 0, sx, sy);
     }
+}
 
 static void
 pointer_handle_button(void *data, struct wl_pointer *pointer, uint32_t serial,
@@ -123,6 +135,7 @@ pointer_handle_button(void *data, struct wl_pointer *pointer, uint32_t serial,
     enum wl_pointer_button_state state = state_w;
     uint32_t sdl_button;
     
+    if  (input->pointer_focus) {
         switch (button) {
             case BTN_LEFT:
                 sdl_button = SDL_BUTTON_LEFT;
@@ -146,6 +159,7 @@ pointer_handle_button(void *data, struct wl_pointer *pointer, uint32_t serial,
         SDL_SendMouseButton(window->sdlwindow, 0,
                             state ? SDL_PRESSED : SDL_RELEASED, sdl_button);
     }
+}
 
 static void
 pointer_handle_axis(void *data, struct wl_pointer *pointer,
@@ -156,6 +170,7 @@ pointer_handle_axis(void *data, struct wl_pointer *pointer,
     enum wl_pointer_axis a = axis;
     int x, y;
 
+    if (input->pointer_focus) {
         switch (a) {
             case WL_POINTER_AXIS_VERTICAL_SCROLL:
                 x = 0;
@@ -171,6 +186,7 @@ pointer_handle_axis(void *data, struct wl_pointer *pointer,
 
         SDL_SendMouseWheel(window->sdlwindow, 0, x, y);
     }
+}
 
 static const struct wl_pointer_listener pointer_listener = {
     pointer_handle_enter,
@@ -234,8 +250,10 @@ keyboard_handle_enter(void *data, struct wl_keyboard *keyboard,
 
     input->keyboard_focus = window;
     window->keyboard_device = input;
+    if (window) {
         SDL_SetKeyboardFocus(window->sdlwindow);
     }
+}
 
 static void
 keyboard_handle_leave(void *data, struct wl_keyboard *keyboard,
@@ -340,11 +358,10 @@ Wayland_display_add_input(SDL_VideoData *d, uint32_t id)
 {
     struct SDL_WaylandInput *input;
 
-    input = malloc(sizeof *input);
+    input = SDL_calloc(1, sizeof *input);
     if (input == NULL)
         return;
 
-    memset(input, 0, sizeof *input);
     input->display = d;
     input->seat = wl_registry_bind(d->registry, id, &wl_seat_interface, 1);
 
@@ -378,7 +395,7 @@ void Wayland_display_destroy_input(SDL_VideoData *d)
     if (input->xkb.keymap)
         WAYLAND_xkb_keymap_unref(input->xkb.keymap);
 
-    free(input);
+    SDL_free(input);
     d->input = NULL;
 }
 

src/video/wayland/SDL_waylandmouse.c

@@ -181,6 +181,7 @@ Wayland_CreateCursor(SDL_Surface *surface, int hot_x, int hot_y)
                    surface->h * surface->pitch);
 
         data->surface = wl_compositor_create_surface(wd->compositor);
+        wl_surface_set_user_data(data->surface, NULL);
         wl_surface_attach(data->surface,
                           data->buffer,
                           0,
@@ -214,6 +215,7 @@ CreateCursorFromWlCursor(SDL_VideoData *d, struct wl_cursor *wlcursor)
          * reference to it here */
         data->buffer = NULL;
         data->surface = wl_compositor_create_surface(d->compositor);
+        wl_surface_set_user_data(data->surface, NULL);
         wl_surface_attach(data->surface,
                           WAYLAND_wl_cursor_image_get_buffer(wlcursor->images[0]),
                           0,