Alexandros Frantzis : winewayland.drv: Remove wayland_surface destruction double locking.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: e0a5f3564972b0a51e3c14a8fcf1e8f0dcdd0c73
URL:    https://gitlab.winehq.org/wine/wine/-/commit/e0a5f3564972b0a51e3c14a8fcf1e8f...

Author: Alexandros Frantzis 
Date:   Tue Sep 12 15:37:42 2023 +0300

winewayland.drv: Remove wayland_surface destruction double locking.

Ignoring the possibility of HWND recycling allows us to use a simpler
scheme to ensure valid access to the wayland_surface associated with an
xdg_surface during event handling. The scheme involves setting HWND as
the xdg_surface user data and using that to get to the wayland_surface.

The prerequisite for this code to be correct is that the wayland surface
destruction for a HWND must be performed under the wayland_win_data
mutex.

---

dlls/winewayland.drv/wayland_surface.c | 25 +++----------------------
 dlls/winewayland.drv/waylanddrv.h      |  1 +
 dlls/winewayland.drv/window.c          | 17 +++++++++++++++++
 3 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/dlls/winewayland.drv/wayland_surface.c b/dlls/winewayland.drv/wayland_surface.c
index 7e77c9ba55f..e8ab52da543 100644
--- a/dlls/winewayland.drv/wayland_surface.c
+++ b/dlls/winewayland.drv/wayland_surface.c
@@ -33,38 +33,22 @@

WINE_DEFAULT_DEBUG_CHANNEL(waylanddrv);

-/* Protects access to the user data of xdg_surface */
-static pthread_mutex_t xdg_data_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-static struct wayland_surface *wayland_surface_lock_xdg(struct xdg_surface *xdg_surface)
-{
-    struct wayland_surface *surface;
-
-    pthread_mutex_lock(&xdg_data_mutex);
-    surface = xdg_surface_get_user_data(xdg_surface);
-    if (surface) pthread_mutex_lock(&surface->mutex);
-    pthread_mutex_unlock(&xdg_data_mutex);
-
-    return surface;
-}
-
 static void xdg_surface_handle_configure(void *data, struct xdg_surface *xdg_surface,
                                          uint32_t serial)
 {
     struct wayland_surface *surface;
     BOOL initial_configure = FALSE;
-    HWND hwnd;
+    HWND hwnd = data;

TRACE("serial=%u\n", serial);

-    if (!(surface = wayland_surface_lock_xdg(xdg_surface))) return;
+    if (!(surface = wayland_surface_lock_hwnd(hwnd))) return;

/* Handle this event only if wayland_surface is still associated with
      * the target xdg_surface. */
     if (surface->xdg_surface == xdg_surface)
     {
         initial_configure = surface->current_serial == 0;
-        hwnd = surface->hwnd;
         surface->current_serial = serial;
         xdg_surface_ack_configure(xdg_surface, serial);
     }
@@ -132,7 +116,6 @@ void wayland_surface_destroy(struct wayland_surface *surface)
     }
     pthread_mutex_unlock(&process_wayland.pointer.mutex);

-    pthread_mutex_lock(&xdg_data_mutex);
     pthread_mutex_lock(&surface->mutex);

if (surface->xdg_toplevel)
@@ -143,7 +126,6 @@ void wayland_surface_destroy(struct wayland_surface *surface)

if (surface->xdg_surface)
     {
-        xdg_surface_set_user_data(surface->xdg_surface, NULL);
         xdg_surface_destroy(surface->xdg_surface);
         surface->xdg_surface = NULL;
     }
@@ -155,7 +137,6 @@ void wayland_surface_destroy(struct wayland_surface *surface)
     }

pthread_mutex_unlock(&surface->mutex);
-    pthread_mutex_unlock(&xdg_data_mutex);

if (surface->latest_window_buffer)
         wayland_shm_buffer_unref(surface->latest_window_buffer);
@@ -179,7 +160,7 @@ void wayland_surface_make_toplevel(struct wayland_surface *surface)
     surface->xdg_surface =
         xdg_wm_base_get_xdg_surface(process_wayland.xdg_wm_base, surface->wl_surface);
     if (!surface->xdg_surface) goto err;
-    xdg_surface_add_listener(surface->xdg_surface, &xdg_surface_listener, surface);
+    xdg_surface_add_listener(surface->xdg_surface, &xdg_surface_listener, surface->hwnd);

surface->xdg_toplevel = xdg_surface_get_toplevel(surface->xdg_surface);
     if (!surface->xdg_toplevel) goto err;
diff --git a/dlls/winewayland.drv/waylanddrv.h b/dlls/winewayland.drv/waylanddrv.h
index f4292e0ae28..6e0b5c6fb10 100644
--- a/dlls/winewayland.drv/waylanddrv.h
+++ b/dlls/winewayland.drv/waylanddrv.h
@@ -166,6 +166,7 @@ void wayland_surface_clear_role(struct wayland_surface *surface) DECLSPEC_HIDDEN
 void wayland_surface_attach_shm(struct wayland_surface *surface,
                                 struct wayland_shm_buffer *shm_buffer,
                                 HRGN surface_damage_region) DECLSPEC_HIDDEN;
+struct wayland_surface *wayland_surface_lock_hwnd(HWND hwnd) DECLSPEC_HIDDEN;

/**********************************************************************
  *          Wayland SHM buffer
diff --git a/dlls/winewayland.drv/window.c b/dlls/winewayland.drv/window.c
index efe72baf92e..958bc5dbe68 100644
--- a/dlls/winewayland.drv/window.c
+++ b/dlls/winewayland.drv/window.c
@@ -338,3 +338,20 @@ void wayland_window_flush(HWND hwnd)

wayland_win_data_release(data);
 }
+
+/**********************************************************************
+ *           wayland_surface_lock_hwnd
+ */
+struct wayland_surface *wayland_surface_lock_hwnd(HWND hwnd)
+{
+    struct wayland_win_data *data = wayland_win_data_get(hwnd);
+    struct wayland_surface *surface;
+
+    if (!data) return NULL;
+
+    if ((surface = data->wayland_surface)) pthread_mutex_lock(&surface->mutex);
+
+    wayland_win_data_release(data);
+
+    return surface;
+}