dix: add screen hook for post-window-destroy

In contrast to the already existing WindowDestroy hook, this one is
called *after* the driver's DestroyWindow() proc.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

dix/screen_hooks.c

@@ -26,6 +26,7 @@
     }
 
 DECLARE_HOOK_PROC(WindowDestroy, hookWindowDestroy, XorgScreenWindowDestroyProcPtr);
+DECLARE_HOOK_PROC(PostWindowDestroy, hookWindowDestroy, XorgScreenWindowDestroyProcPtr);
 DECLARE_HOOK_PROC(WindowPosition, hookWindowPosition, XorgScreenWindowPositionProcPtr);
 DECLARE_HOOK_PROC(Close, hookClose, XorgScreenCloseProcPtr);
 DECLARE_HOOK_PROC(PostClose, hookPostClose, XorgScreenCloseProcPtr);
@@ -42,7 +43,11 @@ int dixScreenRaiseWindowDestroy(WindowPtr pWin)
 
     CallCallbacks(&pScreen->hookWindowDestroy, pWin);
 
-    return (pScreen->DestroyWindow ? pScreen->DestroyWindow(pWin) : Success);
+    int rc = pScreen->DestroyWindow ? pScreen->DestroyWindow(pWin) : Success;
+
+    CallCallbacks(&pScreen->hookPostWindowDestroy, pWin);
+
+    return rc;
 }
 
 void dixScreenRaiseWindowPosition(WindowPtr pWin, uint32_t x, uint32_t y)

dix/screen_hooks_priv.h

@@ -34,7 +34,7 @@ typedef void (*XorgScreenWindowDestroyProcPtr)(CallbackListPtr *pcbl,
                                                WindowPtr pWindow);
 
 /**
- * @brief register a window on the given screen
+ * @brief register a window destructor on the given screen
  *
  * @param pScreen pointer to the screen to register the destructor into
  * @param func pointer to the window destructor function
@@ -73,6 +73,34 @@ void dixScreenHookWindowDestroy(ScreenPtr pScreen,
 void dixScreenUnhookWindowDestroy(ScreenPtr pScreen,
                                   XorgScreenWindowDestroyProcPtr func);
 
+/**
+ * @brief register a post window destructor on the given screen
+ *
+ * @param pScreen pointer to the screen to register the destructor into
+ * @param func pointer to the window destructor function
+ * @param arg opaque pointer passed to the destructor
+ *
+ * Similar to dixScreenHookWindowDestroy, but the hook is run *after* the screen
+ * drivers's DestroyWindow() proc.
+ *
+ **/
+void dixScreenHookPostWindowDestroy(ScreenPtr pScreen,
+                                    XorgScreenWindowDestroyProcPtr func);
+
+/**
+ * @brief unregister a window destructor on the given screen
+ *
+ * @param pScreen pointer to the screen to unregister the destructor from
+ * @param func pointer to the window destructor function
+ * @param arg opaque pointer passed to the destructor
+ *
+ * @see dixScreenHookWindowDestroy
+ *
+ * Unregister a window destructor hook registered via @ref dixScreenHookWindowDestroy
+ **/
+void dixScreenUnhookPostWindowDestroy(ScreenPtr pScreen,
+                                      XorgScreenWindowDestroyProcPtr func);
+
 typedef struct {
     WindowPtr window;
     int32_t x;

include/scrnintstr.h

@@ -700,6 +700,10 @@ typedef struct _Screen {
     /* additional screen post-close notify hooks (replaces wrapping CloseScreen)
        should NOT be touched outside of DIX core */
     CallbackListPtr hookPostClose;
+
+    /* additional post window destructors (replaces wrapping DestroyWindow).
+       should NOT be touched outside of DIX core */
+    CallbackListPtr hookPostWindowDestroy;
 } ScreenRec;
 
 static inline RegionPtr