xwayland: Separate DamagePtr into separate window data

This will be dissociated in future commits to handle the cases
where windows are being realized before there is a compositor
handling redirection.

In that case, we still want the DamagePtr to be registered upfront
on RealizeWindowProc before a corresponding xwl_window might be
created. Most notably, it cannot be lazily created on
SetWindowPixmapProc as damage accounting gets broken.

Signed-off-by: Carlos Garnacho <carlosg@gnome.org>

hw/xwayland/xwayland.c

@@ -161,6 +161,7 @@ ddxProcessArgument(int argc, char *argv[], int i)
 static DevPrivateKeyRec xwl_window_private_key;
 static DevPrivateKeyRec xwl_screen_private_key;
 static DevPrivateKeyRec xwl_pixmap_private_key;
+static DevPrivateKeyRec xwl_damage_private_key;
 
 static struct xwl_window *
 xwl_window_get(WindowPtr window)
@@ -403,8 +404,14 @@ xwl_cursor_confined_to(DeviceIntPtr device,
 static void
 damage_report(DamagePtr pDamage, RegionPtr pRegion, void *data)
 {
-    struct xwl_window *xwl_window = data;
-    struct xwl_screen *xwl_screen = xwl_window->xwl_screen;
+    WindowPtr window = data;
+    struct xwl_window *xwl_window = xwl_window_get(window);
+    struct xwl_screen *xwl_screen;
+
+    if (!xwl_window)
+        return;
+
+    xwl_screen = xwl_window->xwl_screen;
 
 #ifdef GLAMOR_HAS_GBM
     if (xwl_window->present_flipped) {
@@ -426,6 +433,47 @@ damage_destroy(DamagePtr pDamage, void *data)
 {
 }
 
+static Bool
+register_damage(WindowPtr window)
+{
+    DamagePtr damage;
+
+    damage = DamageCreate(damage_report, damage_destroy, DamageReportNonEmpty,
+                          FALSE, window->drawable.pScreen, window);
+    if (damage == NULL) {
+        ErrorF("Failed creating damage\n");
+        return FALSE;
+    }
+
+    DamageRegister(&window->drawable, damage);
+    DamageSetReportAfterOp(damage, TRUE);
+
+    dixSetPrivate(&window->devPrivates, &xwl_damage_private_key, damage);
+
+    return TRUE;
+}
+
+static void
+unregister_damage(WindowPtr window)
+{
+    DamagePtr damage;
+
+    damage = dixLookupPrivate(&window->devPrivates, &xwl_damage_private_key);
+    if (!damage)
+        return;
+
+    DamageUnregister(damage);
+    DamageDestroy(damage);
+
+    dixSetPrivate(&window->devPrivates, &xwl_damage_private_key, NULL);
+}
+
+static DamagePtr
+window_get_damage(WindowPtr window)
+{
+    return dixLookupPrivate(&window->devPrivates, &xwl_damage_private_key);
+}
+
 static void
 shell_surface_ping(void *data,
                    struct wl_shell_surface *shell_surface, uint32_t serial)
@@ -581,18 +629,10 @@ xwl_realize_window(WindowPtr window)
 
     wl_surface_set_user_data(xwl_window->surface, xwl_window);
 
-    xwl_window->damage =
-        DamageCreate(damage_report, damage_destroy, DamageReportNonEmpty,
-                     FALSE, screen, xwl_window);
-    if (xwl_window->damage == NULL) {
-        ErrorF("Failed creating damage\n");
-        goto err_surf;
-    }
-
     compRedirectWindow(serverClient, window, CompositeRedirectManual);
 
-    DamageRegister(&window->drawable, xwl_window->damage);
-    DamageSetReportAfterOp(xwl_window->damage, TRUE);
+    if (!register_damage(window))
+        goto err_surf;
 
     dixSetPrivate(&window->devPrivates, &xwl_window_private_key, xwl_window);
     xorg_list_init(&xwl_window->link_damage);
@@ -656,8 +696,8 @@ xwl_unrealize_window(WindowPtr window)
 
     wl_surface_destroy(xwl_window->surface);
     xorg_list_del(&xwl_window->link_damage);
-    DamageUnregister(xwl_window->damage);
-    DamageDestroy(xwl_window->damage);
+    unregister_damage(window);
+
     if (xwl_window->frame_callback)
         wl_callback_destroy(xwl_window->frame_callback);
 
@@ -719,7 +759,7 @@ xwl_window_post_damage(struct xwl_window *xwl_window)
 
     assert(!xwl_window->frame_callback);
 
-    region = DamageRegion(xwl_window->damage);
+    region = DamageRegion(window_get_damage(xwl_window->window));
     pixmap = (*xwl_screen->screen->GetWindowPixmap) (xwl_window->window);
 
 #ifdef XWL_HAS_GLAMOR
@@ -756,7 +796,7 @@ xwl_window_post_damage(struct xwl_window *xwl_window)
     wl_callback_add_listener(xwl_window->frame_callback, &frame_listener, xwl_window);
 
     wl_surface_commit(xwl_window->surface);
-    DamageEmpty(xwl_window->damage);
+    DamageEmpty(window_get_damage(xwl_window->window));
 
     xorg_list_del(&xwl_window->link_damage);
 }
@@ -993,6 +1033,8 @@ xwl_screen_init(ScreenPtr pScreen, int argc, char **argv)
         return FALSE;
     if (!dixRegisterPrivateKey(&xwl_pixmap_private_key, PRIVATE_PIXMAP, 0))
         return FALSE;
+    if (!dixRegisterPrivateKey(&xwl_damage_private_key, PRIVATE_WINDOW, 0))
+        return FALSE;
 
     dixSetPrivate(&pScreen->devPrivates, &xwl_screen_private_key, xwl_screen);
     xwl_screen->screen = pScreen;

hw/xwayland/xwayland.h

@@ -175,7 +175,6 @@ struct xwl_window {
     struct wl_surface *surface;
     struct wl_shell_surface *shell_surface;
     WindowPtr window;
-    DamagePtr damage;
     struct xorg_list link_damage;
     struct wl_callback *frame_callback;
     Bool allow_commits;