[gtk+/popovers: 30/42] popover: Fix memory management of popovers

[Carlos Garnacho <carlosg src gnome org>]

commit 3911f27a275af4c353ed1065d989a8bc45ba1e3f
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Jan 9 17:21:43 2014 +0100

    popover: Fix memory management of popovers
    
    Popovers are strange in the sense that they aren't attached to a
    parent directly, they rely on the relative_to widget so the toplevel
    is shared, and when they have a parent, it is the toplevel itself,
    not relative_to. This also means that there are conditions where the
    popover loses it's parent, so they must survive unparenting.
    
    The previous code would be floating the last reference as soon as the
    parent is gone, but it was non-obvious who'd own that reference. So
    fix this situation by granting the ownership of popovers to their
    relative_to widget, an extra reference may be held by the toplevel
    when the popover has a parent, but the popover object will be
    guaranteed to be alive as long as the parent lives.
    
    This way, memory management of popovers is as hidden from the user
    as regular widgets within containers are, users are free to call
    gtk_widget_destroy() on a popover, but it'd eventually become
    destructed when relative_to is.

 gtk/gtkpopover.c    |   56 +++++++++++++++++++++++++++++++++++++++++++++-----
 gtk/gtktexthandle.c |    7 +++--
 gtk/gtkwindow.c     |    3 ++
 3 files changed, 57 insertions(+), 9 deletions(-)
---
diff --git a/gtk/gtkpopover.c b/gtk/gtkpopover.c
index 55a2274..e425641 100644
--- a/gtk/gtkpopover.c
+++ b/gtk/gtkpopover.c
@@ -70,6 +70,8 @@ struct _GtkPopoverPrivate
   guint current_position   : 2;
 };
 
+static GQuark quark_widget_popovers = 0;
+
 static void gtk_popover_update_position    (GtkPopover *popover);
 static void gtk_popover_update_relative_to (GtkPopover *popover,
                                             GtkWidget  *relative_to);
@@ -163,6 +165,7 @@ gtk_popover_dispose (GObject *object)
   if (priv->widget)
     gtk_popover_update_relative_to (popover, NULL);
 
+  gtk_widget_set_visible (GTK_WIDGET (object), FALSE);
   G_OBJECT_CLASS (gtk_popover_parent_class)->dispose (object);
 }
 
@@ -877,6 +880,8 @@ gtk_popover_class_init (GtkPopoverClass *klass)
                                                       P_("Position to place the bubble window"),
                                                       GTK_TYPE_POSITION_TYPE, GTK_POS_TOP,
                                                       GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT));
+
+  quark_widget_popovers = g_quark_from_static_string ("gtk-quark-widget-popovers");
 }
 
 static void
@@ -913,12 +918,7 @@ _gtk_popover_parent_hierarchy_changed (GtkWidget  *widget,
     gtk_window_remove_popover (priv->window, GTK_WIDGET (popover));
 
   if (new_window)
-    {
-      gtk_window_add_popover (new_window, GTK_WIDGET (popover));
-      g_object_unref (popover);
-    }
-  else
-    g_object_force_floating (G_OBJECT (popover));
+    gtk_window_add_popover (new_window, GTK_WIDGET (popover));
 
   priv->window = new_window;
 
@@ -929,6 +929,8 @@ _gtk_popover_parent_hierarchy_changed (GtkWidget  *widget,
 
   if (gtk_widget_is_visible (GTK_WIDGET (popover)))
     gtk_widget_queue_resize (GTK_WIDGET (popover));
+
+  g_object_unref (popover);
 }
 
 static void
@@ -947,6 +949,40 @@ _gtk_popover_parent_size_allocate (GtkWidget     *widget,
 }
 
 static void
+widget_manage_popover (GtkWidget  *widget,
+                       GtkPopover *popover)
+{
+  GHashTable *popovers;
+
+  popovers = g_object_get_qdata (G_OBJECT (widget), quark_widget_popovers);
+
+  if (G_UNLIKELY (!popovers))
+    {
+      popovers = g_hash_table_new_full (NULL, NULL,
+                                        (GDestroyNotify) g_object_unref, NULL);
+      g_object_set_qdata_full (G_OBJECT (widget),
+                               quark_widget_popovers, popovers,
+                               (GDestroyNotify) g_hash_table_unref);
+    }
+
+  g_hash_table_add (popovers, g_object_ref_sink (popover));
+}
+
+static void
+widget_unmanage_popover (GtkWidget  *widget,
+                         GtkPopover *popover)
+{
+  GHashTable *popovers;
+
+  popovers = g_object_get_qdata (G_OBJECT (widget), quark_widget_popovers);
+
+  if (G_UNLIKELY (!popovers))
+    return;
+
+  g_hash_table_remove (popovers, popover);
+}
+
+static void
 gtk_popover_update_relative_to (GtkPopover *popover,
                                 GtkWidget  *relative_to)
 {
@@ -957,6 +993,8 @@ gtk_popover_update_relative_to (GtkPopover *popover,
   if (priv->widget == relative_to)
     return;
 
+  g_object_ref (popover);
+
   if (priv->window)
     {
       gtk_window_remove_popover (priv->window, GTK_WIDGET (popover));
@@ -971,6 +1009,8 @@ gtk_popover_update_relative_to (GtkPopover *popover,
         g_signal_handler_disconnect (priv->widget, priv->size_allocate_id);
       if (g_signal_handler_is_connected (priv->widget, priv->unmap_id))
         g_signal_handler_disconnect (priv->widget, priv->unmap_id);
+
+      widget_unmanage_popover (priv->widget, popover);
     }
 
   priv->widget = relative_to;
@@ -993,12 +1033,16 @@ gtk_popover_update_relative_to (GtkPopover *popover,
         g_signal_connect (priv->widget, "unmap",
                           G_CALLBACK (_gtk_popover_parent_unmap),
                           popover);
+
+      /* Give ownership of the popover to widget */
+      widget_manage_popover (priv->widget, popover);
     }
 
   if (priv->window)
     gtk_window_add_popover (priv->window, GTK_WIDGET (popover));
 
   _gtk_popover_update_context_parent (popover);
+  g_object_unref (popover);
 }
 
 static void
diff --git a/gtk/gtktexthandle.c b/gtk/gtktexthandle.c
index af73f58..70de3b7 100644
--- a/gtk/gtktexthandle.c
+++ b/gtk/gtktexthandle.c
@@ -237,7 +237,7 @@ _gtk_text_handle_ensure_widget (GtkTextHandle         *handle,
                         G_CALLBACK (gtk_text_handle_widget_style_updated),
                         handle);
 
-      priv->windows[pos].widget = widget;
+      priv->windows[pos].widget = g_object_ref_sink (widget);
       window = gtk_widget_get_ancestor (priv->parent, GTK_TYPE_WINDOW);
       gtk_window_add_popover (GTK_WINDOW (window), widget);
     }
@@ -305,11 +305,12 @@ gtk_text_handle_finalize (GObject *object)
 
   priv = GTK_TEXT_HANDLE (object)->priv;
 
+  /* We sank the references, unref here */
   if (priv->windows[GTK_TEXT_HANDLE_POSITION_SELECTION_START].widget)
-    gtk_widget_destroy (priv->windows[GTK_TEXT_HANDLE_POSITION_SELECTION_START].widget);
+    g_object_unref (priv->windows[GTK_TEXT_HANDLE_POSITION_SELECTION_START].widget);
 
   if (priv->windows[GTK_TEXT_HANDLE_POSITION_SELECTION_END].widget)
-    gtk_widget_destroy (priv->windows[GTK_TEXT_HANDLE_POSITION_SELECTION_END].widget);
+    g_object_unref (priv->windows[GTK_TEXT_HANDLE_POSITION_SELECTION_END].widget);
 
   G_OBJECT_CLASS (_gtk_text_handle_parent_class)->finalize (object);
 }
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 47c32a3..7f63295 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -2662,12 +2662,15 @@ static void
 gtk_window_dispose (GObject *object)
 {
   GtkWindow *window = GTK_WINDOW (object);
+  GtkWindowPrivate *priv = window->priv;
 
   gtk_window_set_focus (window, NULL);
   gtk_window_set_default (window, NULL);
   unset_titlebar (window);
   remove_attach_widget (window);
 
+  g_hash_table_remove_all (priv->popovers);
+
   G_OBJECT_CLASS (gtk_window_parent_class)->dispose (object);
 }