[gtk+] quartz: handle recursive CFRunLoops

[Michael Natterer <mitch src gnome org>]

commit d1c6bcb85c5eb37b9b9b82bfb973853b07aa06a0
Author: Michael Natterer <mitch lanedo com>
Date:   Sun Nov 6 23:12:57 2011 +0100

    quartz: handle recursive CFRunLoops
    
    Fixes e.g. crashs when dropping from finder.
    
    Turn the "getting_events" boolean into a counter to handle poll_func()
    being called recursively, and track the loop depth correctly by
    changing its counter before bailing out in run_loop_observer_callback().
    This way we reallocate our autorelease pool at the right time, and
    don't kill memory that is still in use by outer run loops.
    
    Also drain, not release the pool, just for some defensive forward
    compatibility.
    (cherry picked from commit ef9a92d225f7257f56c3a8b7b28ddd9a734e38e6)

 gdk/quartz/gdkeventloop-quartz.c |   49 ++++++++++++++++++++++---------------
 1 files changed, 29 insertions(+), 20 deletions(-)
---
diff --git a/gdk/quartz/gdkeventloop-quartz.c b/gdk/quartz/gdkeventloop-quartz.c
index 32ea8a4..702238c 100644
--- a/gdk/quartz/gdkeventloop-quartz.c
+++ b/gdk/quartz/gdkeventloop-quartz.c
@@ -124,7 +124,7 @@ static NSAutoreleasePool *autorelease_pool;
  * a run loop iteration, so we need to detect that and avoid triggering
  * our "run the GLib main looop while the run loop is active machinery.
  */
-static gboolean getting_events;
+static gint getting_events = 0;
 
 /************************************************************
  *********              Select Thread               *********
@@ -632,17 +632,18 @@ gdk_event_check (GSource *source)
 
   GDK_THREADS_ENTER ();
 
-/* Refresh the autorelease pool if we're at the base CFRunLoop level
- * (indicated by current_loop_level) and the base g_main_loop level
- * (indicated by g_main_depth()). Messing with the autorelease pool at
- * any level of nesting can cause access to deallocated memory because
- * autorelease_pool is static and releasing a pool will cause all
- * pools allocated inside of it to be released as well.
- */
+  /* Refresh the autorelease pool if we're at the base CFRunLoop level
+   * (indicated by current_loop_level) and the base g_main_loop level
+   * (indicated by g_main_depth()). Messing with the autorelease pool at
+   * any level of nesting can cause access to deallocated memory because
+   * autorelease_pool is static and releasing a pool will cause all pools
+   * allocated inside of it to be released as well.
+   */
   if (current_loop_level == 0 && g_main_depth() == 0)
     {
       if (autorelease_pool)
-	[autorelease_pool release];
+        [autorelease_pool drain];
+
       autorelease_pool = [[NSAutoreleasePool alloc] init];
     }
 
@@ -710,12 +711,12 @@ poll_func (GPollFD *ufds,
   else
     limit_date = [NSDate dateWithTimeIntervalSinceNow:timeout_/1000.0];
 
-  getting_events = TRUE;
+  getting_events++;
   event = [NSApp nextEventMatchingMask: NSAnyEventMask
 	                     untilDate: limit_date
 	                        inMode: NSDefaultRunLoopMode
                                dequeue: YES];
-  getting_events = FALSE;
+  getting_events--;
 
   if (n_ready < 0)
     n_ready = select_thread_collect_poll (ufds, nfds);
@@ -776,8 +777,6 @@ query_main_context (GMainContext *context,
 static void
 run_loop_entry (void)
 {
-  current_loop_level++;
-
   if (acquired_loop_level == -1)
     {
       if (g_main_context_acquire (NULL))
@@ -926,16 +925,13 @@ run_loop_after_waiting (void)
 static void
 run_loop_exit (void)
 {
-  g_return_if_fail (current_loop_level > 0);
-
-  if (current_loop_level == acquired_loop_level)
+  /* + 1 because we decrement current_loop_level separately in observer_callback() */
+  if ((current_loop_level + 1) == acquired_loop_level)
     {
       g_main_context_release (NULL);
       acquired_loop_level = -1;
       GDK_NOTE (EVENTLOOP, g_print ("EventLoop: Ended tracking run loop activity\n"));
     }
-  
-  current_loop_level--;
 }
 
 static void
@@ -943,9 +939,22 @@ run_loop_observer_callback (CFRunLoopObserverRef observer,
 			    CFRunLoopActivity    activity,
 			    void                *info)
 {
-  if (getting_events) /* Activity we triggered */
+  switch (activity)
+    {
+    case kCFRunLoopEntry:
+      current_loop_level++;
+      break;
+    case kCFRunLoopExit:
+      g_return_if_fail (current_loop_level > 0);
+      current_loop_level--;
+      break;
+    default:
+      break;
+    }
+
+  if (getting_events > 0) /* Activity we triggered */
     return;
-  
+
   switch (activity)
     {
     case kCFRunLoopEntry: