ShellWindowTracker: fix a reference counting bug

When retrieving a ShellApp from the GHashTable of child processes,
we need to take an extra reference, that the GHashTable of windows
to apps will own.
Also add some documentation to avoid repeating this bug in the future.

https://bugzilla.gnome.org/show_bug.cgi?id=642699

diff --git a/src/shell-window-tracker.c b/src/shell-window-tracker.c
index a0255b501b79369cc353777ed30449b678d9bfc0..25ee54437b4e1b09c0450bba024199a4a5790109 100644 (file)
--- a/src/shell-window-tracker.c
+++ b/src/shell-window-tracker.c
@@ -382,10 +382,21 @@ get_app_from_window_group (ShellWindowTracker  *monitor,
   return result;
 }
 
+/**
+ * get_app_from_window_pid:
+ * @monitor: a #ShellWindowTracker
+ * @window: a #MetaWindow
+ *
+ * Check if the pid associated with @window corresponds to an
+ * application we launched.
+ *
+ * Return value: (transfer full): A newly-referenced #ShellApp, or %NULL
+ */
 static ShellApp *
 get_app_from_window_pid (ShellWindowTracker  *tracker,
                          MetaWindow          *window)
 {
+  ShellApp *result;
   int pid;
 
   if (meta_window_is_remote (window))
@@ -396,7 +407,11 @@ get_app_from_window_pid (ShellWindowTracker  *tracker,
   if (pid == -1)
     return NULL;
 
-  return g_hash_table_lookup (tracker->launched_pid_to_app, GINT_TO_POINTER (pid));
+  result = g_hash_table_lookup (tracker->launched_pid_to_app, GINT_TO_POINTER (pid));
+  if (result != NULL)
+    g_object_ref (result);
+
+  return result;
 }
 
 /**
@@ -405,6 +420,8 @@ get_app_from_window_pid (ShellWindowTracker  *tracker,
  * Determines the application associated with a window, using
  * all available information such as the window's MetaGroup,
  * and what we know about other windows.
+ *
+ * Returns: (transfer full): a #ShellApp, or NULL if none is found
  */
 static ShellApp *
 get_app_for_window (ShellWindowTracker    *monitor,