xwayland: Defer surface realization to block handlerwayland-netwm-etc

In addition to batching requests better, this also optimizes out the
case of a window destroyed before we flush the realization to wayland.

This does come at a cost, in that we're no longer allocating everything
we need for the surface at RealizeWindow time, so it's possible to end
up with an X window with no corresponding wayland surface; hence the
surface validity check in the damage blockhandler.  But we do retry
surface creation every time we block until it succeeds, so if it's just
a transient allocation problem we should eventually push through.

Signed-off-by: Adam Jackson <ajax@redhat.com>

2 files changed, 28 insertions, 3 deletions

diff --git a/hw/xwayland/xwayland.c b/hw/xwayland/xwayland.c
index 031c8f18b..9190f6536 100644
--- a/hw/xwayland/xwayland.c
+++ b/hw/xwayland/xwayland.c
@@ -329,7 +329,9 @@ xwl_realize_window(WindowPtr window)
     xwl_window = calloc(sizeof *xwl_window, 1);
     xwl_window->xwl_screen = xwl_screen;
     xwl_window->window = window;
-    xwl_window->surface = xwl_create_surface(xwl_screen, xwl_window);
+    xorg_list_init(&xwl_window->link_realize);
+    xorg_list_append(&xwl_window->link_realize,
+                     &xwl_screen->realize_window_list);
 
     dixSetPrivate(&window->devPrivates, &xwl_window_private_key, xwl_window);
 
@@ -372,7 +374,10 @@ xwl_unrealize_window(WindowPtr window)
     if (!xwl_window)
         return ret;
 
-    wl_surface_destroy(xwl_window->surface);
+    if (!xorg_list_is_empty(&xwl_window->link_realize))
+        xorg_list_del(&xwl_window->link_realize);
+    if (xwl_window->surface)
+        wl_surface_destroy(xwl_window->surface);
     if (RegionNotEmpty(DamageRegion(xwl_window->damage)))
         xorg_list_del(&xwl_window->link_damage);
     DamageUnregister(xwl_window->damage);
@@ -390,6 +395,20 @@ xwl_save_screen(ScreenPtr pScreen, int on)
 }
 
 static void
+xwl_screen_realize_windows(struct xwl_screen *xwl_screen)
+{
+    struct xwl_window *xwl_window, *cur;
+
+    xorg_list_for_each_entry_safe(xwl_window, cur,
+                                  &xwl_screen->realize_window_list,
+                                  link_realize) {
+        xwl_window->surface = xwl_create_surface(xwl_screen, xwl_window);
+        if (xwl_window->surface)
+            xorg_list_del(&xwl_window->link_realize);
+    }
+}
+
+static void
 xwl_screen_post_damage(struct xwl_screen *xwl_screen)
 {
     struct xwl_window *xwl_window;
@@ -401,7 +420,6 @@ xwl_screen_post_damage(struct xwl_screen *xwl_screen)
     xorg_list_for_each_entry(xwl_window, &xwl_screen->damage_window_list,
                              link_damage) {
         region = DamageRegion(xwl_window->damage);
-
         pixmap = (*xwl_screen->screen->GetWindowPixmap) (xwl_window->window);
 
 #if GLAMOR_HAS_GBM
@@ -411,6 +429,9 @@ xwl_screen_post_damage(struct xwl_screen *xwl_screen)
         if (!xwl_screen->glamor)
             buffer = xwl_shm_pixmap_get_wl_buffer(pixmap);
 
+        if (!xwl_window->surface)
+            continue;
+
         wl_surface_attach(xwl_window->surface, buffer, 0, 0);
         box = RegionExtents(DamageRegion(xwl_window->damage);
         wl_surface_damage(xwl_window->surface, box->x1, box->y1,
@@ -491,6 +512,7 @@ block_handler(void *data, struct timeval **tv, void *read_mask)
     struct xwl_screen *xwl_screen = data;
     int ret;
 
+    xwl_screen_realize_windows(xwl_screen);
     xwl_screen_post_damage(xwl_screen);
 
     while (xwl_screen->prepare_read == 0 &&
@@ -609,6 +631,7 @@ xwl_screen_init(ScreenPtr pScreen, int argc, char **argv)
     xorg_list_init(&xwl_screen->output_list);
     xorg_list_init(&xwl_screen->seat_list);
     xorg_list_init(&xwl_screen->damage_window_list);
+    xorg_list_init(&xwl_screen->realize_window_list);
     xwl_screen->depth = 24;
 
     xwl_screen->display = wl_display_connect(NULL);
diff --git a/hw/xwayland/xwayland.h b/hw/xwayland/xwayland.h
index d82e77e5c..ecbf75efa 100644
--- a/hw/xwayland/xwayland.h
+++ b/hw/xwayland/xwayland.h
@@ -68,6 +68,7 @@ struct xwl_screen {
     struct xorg_list output_list;
     struct xorg_list seat_list;
     struct xorg_list damage_window_list;
+    struct xorg_list realize_window_list;
 
     int wayland_fd;
     struct wl_display *display;
@@ -103,6 +104,7 @@ struct xwl_window {
     WindowPtr window;
     DamagePtr damage;
     struct xorg_list link_damage;
+    struct xorg_list link_realize;
     Bool supports_wm_sync_request;
     XID wm_sync_counter;
 };