[gthumb] filter grid: remove the weak pointer when no longer needed

[Paolo Bacchilega <paobac src gnome org>]

commit 3f366e373f8e2a93c22a3d79b09c06529aeee774
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Mon Dec 22 16:12:39 2014 +0100

    filter grid: remove the weak pointer when no longer needed

 gthumb/gth-filter-grid.c |   13 ++++++++-----
 1 files changed, 8 insertions(+), 5 deletions(-)
---
diff --git a/gthumb/gth-filter-grid.c b/gthumb/gth-filter-grid.c
index 53f798f..b6e96fe 100644
--- a/gthumb/gth-filter-grid.c
+++ b/gthumb/gth-filter-grid.c
@@ -357,9 +357,12 @@ preview_task_free (PreviewTask *task)
 static void
 generate_preview_data_free (GeneratePreviewData *data)
 {
-       if ((data->self != NULL) && (data->self->priv->gp_data == data))
-               data->self->priv->gp_data = NULL;
        cairo_surface_destroy (data->original);
+       if (data->self != NULL) {
+               if (data->self->priv->gp_data == data)
+                       data->self->priv->gp_data = NULL;
+               g_object_remove_weak_pointer (G_OBJECT (data->self), (gpointer *) &data->self);
+       }
        g_list_free_full (data->tasks, (GDestroyNotify) preview_task_free);
        _g_object_unref (data->cancellable);
        _g_object_unref (data->resize_task);
@@ -386,7 +389,7 @@ image_preview_completed_cb (GthTask    *task,
        GeneratePreviewData *data = user_data;
        cairo_surface_t     *preview;
 
-       if (error != NULL) {
+       if ((error != NULL) || (data->self == NULL)) {
                generate_preview_data_free (data);
                return;
        }
@@ -436,7 +439,7 @@ resize_task_completed_cb (GthTask  *task,
        _g_object_unref (data->resize_task);
        data->resize_task = NULL;
 
-       if (error != NULL) {
+       if ((error != NULL) || (data->self == NULL)) {
                generate_preview_data_free (data);
                return;
        }
@@ -499,7 +502,7 @@ gth_filter_grid_generate_previews (GthFilterGrid    *self,
        data->cancellable = NULL;
        data->original = NULL;
 
-       g_object_add_weak_pointer (G_OBJECT (self), &data->self);
+       g_object_add_weak_pointer (G_OBJECT (self), (gpointer *) &data->self);
        self->priv->gp_data = data;
 
        /* collect the (filter, task) pairs */