[gtksourceview/wip/fix-ref-cycle: 2/2] textregion: weak ref to the buffer

[Sébastien Wilmet <swilmet src gnome org>]

commit ba1b0f177e4ac83169cdf952d2066b2bc5580060
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sat Oct 5 22:21:17 2013 +0200

    textregion: weak ref to the buffer
    
    If the buffer is finalized while the text region is still alive, bad
    things happen.

 gtksourceview/gtktextregion.c |   50 ++++++++++++++++++++++++++++++++++++----
 1 files changed, 45 insertions(+), 5 deletions(-)
---
diff --git a/gtksourceview/gtktextregion.c b/gtksourceview/gtktextregion.c
index 59a2dfa..3b1d437 100644
--- a/gtksourceview/gtktextregion.c
+++ b/gtksourceview/gtktextregion.c
@@ -121,13 +121,17 @@ gtk_text_region_new (GtkTextBuffer *buffer)
 {
        GtkTextRegion *region;
 
-       g_return_val_if_fail (buffer != NULL, NULL);
+       g_return_val_if_fail (GTK_IS_TEXT_BUFFER (buffer), NULL);
 
        region = g_new (GtkTextRegion, 1);
-       region->buffer = buffer;
        region->subregions = NULL;
        region->time_stamp = 0;
 
+       region->buffer = buffer;
+
+       g_object_add_weak_pointer (G_OBJECT (buffer),
+                                  (gpointer *)&region->buffer);
+
        return region;
 }
 
@@ -138,7 +142,7 @@ gtk_text_region_destroy (GtkTextRegion *region, gboolean delete_marks)
 
        while (region->subregions) {
                Subregion *sr = region->subregions->data;
-               if (delete_marks) {
+               if (delete_marks && region->buffer != NULL) {
                        gtk_text_buffer_delete_mark (region->buffer, sr->start);
                        gtk_text_buffer_delete_mark (region->buffer, sr->end);
                }
@@ -146,8 +150,14 @@ gtk_text_region_destroy (GtkTextRegion *region, gboolean delete_marks)
                region->subregions = g_list_delete_link (region->subregions,
                                                         region->subregions);
        }
-       region->buffer = NULL;
-       region->time_stamp = 0;
+
+       if (region->buffer != NULL)
+       {
+               g_object_remove_weak_pointer (G_OBJECT (region->buffer),
+                                             (gpointer *)&region->buffer);
+
+               region->buffer = NULL;
+       }
 
        g_free (region);
 }
@@ -199,6 +209,11 @@ gtk_text_region_add (GtkTextRegion     *region,
 
        g_return_if_fail (region != NULL && _start != NULL && _end != NULL);
 
+       if (region->buffer == NULL)
+       {
+               return;
+       }
+
        start = *_start;
        end = *_end;
 
@@ -288,6 +303,11 @@ gtk_text_region_subtract (GtkTextRegion     *region,
 
        g_return_if_fail (region != NULL && _start != NULL && _end != NULL);
 
+       if (region->buffer == NULL)
+       {
+               return;
+       }
+
        start = *_start;
        end = *_end;
 
@@ -417,6 +437,11 @@ gtk_text_region_nth_subregion (GtkTextRegion *region,
 
        g_return_val_if_fail (region != NULL, FALSE);
 
+       if (region->buffer == NULL)
+       {
+               return FALSE;
+       }
+
        sr = g_list_nth_data (region->subregions, subregion);
        if (sr == NULL)
                return FALSE;
@@ -443,6 +468,11 @@ gtk_text_region_intersect (GtkTextRegion     *region,
 
        g_return_val_if_fail (region != NULL && _start != NULL && _end != NULL, NULL);
 
+       if (region->buffer == NULL)
+       {
+               return NULL;
+       }
+
        start = *_start;
        end = *_end;
 
@@ -612,6 +642,11 @@ gtk_text_region_iterator_get_subregion (GtkTextRegionIterator *iter,
        g_return_if_fail (check_iterator (real));
        g_return_if_fail (real->subregions != NULL);
 
+       if (real->region->buffer == NULL)
+       {
+               return;
+       }
+
        sr = (Subregion*)real->subregions->data;
        g_return_if_fail (sr != NULL);
 
@@ -628,6 +663,11 @@ gtk_text_region_debug_print (GtkTextRegion *region)
 
        g_return_if_fail (region != NULL);
 
+       if (region->buffer == NULL)
+       {
+               return;
+       }
+
        g_print ("Subregions: ");
        l = region->subregions;
        while (l) {