[PATCH] xwayland: Avoid repeatedly looping through window ancestor chain

[Roman Gilg]

Calling xwl_window_from_window means looping through the window ancestor
chain whenever it is called on a child window or on an automatically
redirected window.

Since these properties and the potential ancestor's xwl_window are constant
between window realization and unrealization, we can omit the looping by
always putting the respective xwl_window in the Window's private field on
its realization. If the Window doesn't feature an xwl_window on its own,
it's the xwl_window of its first ancestor with one.

Signed-off-by: Roman Gilg <subdiff at gmail.com>
---
 hw/xwayland/xwayland-input.c |  2 +-
 hw/xwayland/xwayland.c       | 54 ++++++++++++++++++++++++--------------------
 hw/xwayland/xwayland.h       |  2 +-
 3 files changed, 31 insertions(+), 27 deletions(-)

diff --git a/hw/xwayland/xwayland-input.c b/hw/xwayland/xwayland-input.c
index 92e530d..5a905c7 100644
--- a/hw/xwayland/xwayland-input.c
+++ b/hw/xwayland/xwayland-input.c
@@ -1068,7 +1068,7 @@ xwl_keyboard_activate_grab(DeviceIntPtr device, GrabPtr grab, TimeStamp time, Bo
         if (xwl_seat == NULL)
             xwl_seat = find_matching_seat(device);
         if (xwl_seat)
-            set_grab(xwl_seat, xwl_window_from_window(grab->window));
+            set_grab(xwl_seat, xwl_window_of_top(grab->window));
     }
 
     ActivateKeyboardGrab(device, grab, time, passive);
diff --git a/hw/xwayland/xwayland.c b/hw/xwayland/xwayland.c
index cb929ca..79deead 100644
--- a/hw/xwayland/xwayland.c
+++ b/hw/xwayland/xwayland.c
@@ -105,12 +105,23 @@ static DevPrivateKeyRec xwl_window_private_key;
 static DevPrivateKeyRec xwl_screen_private_key;
 static DevPrivateKeyRec xwl_pixmap_private_key;
 
-static struct xwl_window *
-xwl_window_get(WindowPtr window)
+struct xwl_window *
+xwl_window_of_top(WindowPtr window)
 {
     return dixLookupPrivate(&window->devPrivates, &xwl_window_private_key);
 }
 
+static struct xwl_window *
+xwl_window_of_self(WindowPtr window)
+{
+    struct xwl_window *xwl_window = dixLookupPrivate(&window->devPrivates, &xwl_window_private_key);
+
+    if (xwl_window && xwl_window->window == window)
+        return xwl_window;
+    else
+        return  NULL;
+}
+
 struct xwl_screen *
 xwl_screen_get(ScreenPtr screen)
 {
@@ -195,7 +206,7 @@ xwl_property_callback(CallbackListPtr *pcbl, void *closure,
     if (rec->win->drawable.pScreen != screen)
         return;
 
-    xwl_window = xwl_window_get(rec->win);
+    xwl_window = xwl_window_of_self(rec->win);
     if (!xwl_window)
         return;
 
@@ -234,22 +245,6 @@ xwl_close_screen(ScreenPtr screen)
     return screen->CloseScreen(screen);
 }
 
-struct xwl_window *
-xwl_window_from_window(WindowPtr window)
-{
-    struct xwl_window *xwl_window;
-
-    while (window) {
-        xwl_window = xwl_window_get(window);
-        if (xwl_window)
-            return xwl_window;
-
-        window = window->parent;
-    }
-
-    return NULL;
-}
-
 static struct xwl_seat *
 xwl_screen_get_default_seat(struct xwl_screen *xwl_screen)
 {
@@ -274,7 +269,7 @@ xwl_cursor_warped_to(DeviceIntPtr device,
     if (!xwl_seat)
         xwl_seat = xwl_screen_get_default_seat(xwl_screen);
 
-    xwl_window = xwl_window_from_window(window);
+    xwl_window = xwl_window_of_top(window);
     if (!xwl_window && xwl_seat->focus_window) {
         focus = xwl_seat->focus_window->window;
 
@@ -317,7 +312,7 @@ xwl_cursor_confined_to(DeviceIntPtr device,
         return;
     }
 
-    xwl_window = xwl_window_from_window(window);
+    xwl_window = xwl_window_of_top(window);
     if (!xwl_window && xwl_seat->focus_window) {
         /* Allow confining on InputOnly windows, but only if the geometry
          * is the same than the focus window.
@@ -433,6 +428,7 @@ xwl_realize_window(WindowPtr window)
     struct xwl_screen *xwl_screen;
     struct xwl_window *xwl_window;
     struct wl_region *region;
+    Bool create_xwl_window = TRUE;
     Bool ret;
 
     xwl_screen = xwl_screen_get(screen);
@@ -452,11 +448,17 @@ xwl_realize_window(WindowPtr window)
 
     if (xwl_screen->rootless) {
         if (window->redirectDraw != RedirectDrawManual)
-            return ret;
+            create_xwl_window = FALSE;
     }
     else {
         if (window->parent)
-            return ret;
+            create_xwl_window = FALSE;
+    }
+
+    if (!create_xwl_window) {
+        if (window->parent)
+            dixSetPrivate(&window->devPrivates, &xwl_window_private_key, xwl_window_of_top(window->parent));
+        return ret;
     }
 
     xwl_window = calloc(1, sizeof *xwl_window);
@@ -560,9 +562,11 @@ xwl_unrealize_window(WindowPtr window)
     xwl_screen->UnrealizeWindow = screen->UnrealizeWindow;
     screen->UnrealizeWindow = xwl_unrealize_window;
 
-    xwl_window = xwl_window_get(window);
-    if (!xwl_window)
+    xwl_window = xwl_window_of_self(window);
+    if (!xwl_window) {
+        dixSetPrivate(&window->devPrivates, &xwl_window_private_key, NULL);
         return ret;
+    }
 
     wl_surface_destroy(xwl_window->surface);
     if (RegionNotEmpty(DamageRegion(xwl_window->damage)))
diff --git a/hw/xwayland/xwayland.h b/hw/xwayland/xwayland.h
index 6d3edf3..3adee82 100644
--- a/hw/xwayland/xwayland.h
+++ b/hw/xwayland/xwayland.h
@@ -309,7 +309,7 @@ RRModePtr xwayland_cvt(int HDisplay, int VDisplay,
 void xwl_pixmap_set_private(PixmapPtr pixmap, struct xwl_pixmap *xwl_pixmap);
 struct xwl_pixmap *xwl_pixmap_get(PixmapPtr pixmap);
 
-struct xwl_window *xwl_window_from_window(WindowPtr window);
+struct xwl_window *xwl_window_of_top(WindowPtr window);
 
 Bool xwl_shm_create_screen_resources(ScreenPtr screen);
 PixmapPtr xwl_shm_create_pixmap(ScreenPtr screen, int width, int height,
-- 
2.7.4