[gthumb] use a boxed type for the error argument of the GthTask::completed signal

[Paolo Bacchilega <paobac src gnome org>]

commit a4f7ff2af277357c1467a2ed7cfcdb5d110f4f45
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Thu Feb 3 21:34:46 2011 +0100

    use a boxed type for the error argument of the GthTask::completed signal

 gthumb/glib-utils.c  |   20 ++++++++++++++++++++
 gthumb/glib-utils.h  |    5 +++++
 gthumb/gth-browser.c |    8 ++++----
 gthumb/gth-task.c    |    4 ++--
 4 files changed, 31 insertions(+), 6 deletions(-)
---
diff --git a/gthumb/glib-utils.c b/gthumb/glib-utils.c
index 295bb12..120ad3b 100644
--- a/gthumb/glib-utils.c
+++ b/gthumb/glib-utils.c
@@ -103,6 +103,26 @@ g_object_list_get_type (void)
 }
 
 
+#if NEED_G_TYPE_ERROR
+
+
+GType
+g_error_get_type (void)
+{
+	static GType type = 0;
+
+	if (type == 0)
+		type = g_boxed_type_register_static ("GError",
+						     (GBoxedCopyFunc) g_error_copy,
+						     (GBoxedFreeFunc) g_error_free);
+
+	return type;
+}
+
+
+#endif
+
+
 GEnumValue *
 _g_enum_type_get_value (GType enum_type,
 			int   value)
diff --git a/gthumb/glib-utils.h b/gthumb/glib-utils.h
index 258fe47..7423b12 100644
--- a/gthumb/glib-utils.h
+++ b/gthumb/glib-utils.h
@@ -60,6 +60,10 @@ G_BEGIN_DECLS
 #define ID_LENGTH 8
 #define G_TYPE_OBJECT_LIST (g_object_list_get_type ())
 #define G_TYPE_STRING_LIST (g_string_list_get_type ())
+#ifndef G_TYPE_ERROR
+#define NEED_G_TYPE_ERROR 1
+#define G_TYPE_ERROR (g_error_get_type ())
+#endif
 
 /* signals */
 
@@ -81,6 +85,7 @@ void          _g_clear_object                (gpointer     object_p);
 GList *       _g_object_list_ref             (GList       *list);
 void          _g_object_list_unref           (GList       *list);
 GType         g_object_list_get_type         (void);
+GType         g_error_get_type               (void);
 GEnumValue *  _g_enum_type_get_value         (GType        enum_type,
 					      int          value);
 GEnumValue *  _g_enum_type_get_value_by_nick (GType        enum_type,
diff --git a/gthumb/gth-browser.c b/gthumb/gth-browser.c
index 892793a..0afd31c 100644
--- a/gthumb/gth-browser.c
+++ b/gthumb/gth-browser.c
@@ -4740,10 +4740,10 @@ foreground_task_completed_cb (GthTask    *task,
 	gth_statusbar_set_progress (GTH_STATUSBAR (browser->priv->statusbar), NULL, FALSE, 0.0);
 	gth_browser_update_sensitivity (browser);
 	if (error != NULL) {
-		if (! g_error_matches (error, GTH_TASK_ERROR, GTH_TASK_ERROR_CANCELLED))
-			_gtk_error_dialog_from_gerror_show (GTK_WINDOW (browser), _("Could not perform the operation"), &error);
-		else
-			g_error_free (error);
+		if (! g_error_matches (error, GTH_TASK_ERROR, GTH_TASK_ERROR_CANCELLED)) {
+			GError *local_error = g_error_copy (error);
+			_gtk_error_dialog_from_gerror_show (GTK_WINDOW (browser), _("Could not perform the operation"), &local_error);
+		}
 	}
 
 	g_object_unref (browser->priv->task);
diff --git a/gthumb/gth-task.c b/gthumb/gth-task.c
index da9fe3e..4860191 100644
--- a/gthumb/gth-task.c
+++ b/gthumb/gth-task.c
@@ -105,10 +105,10 @@ gth_task_class_init (GthTaskClass *class)
 			      G_SIGNAL_RUN_LAST,
 			      G_STRUCT_OFFSET (GthTaskClass, completed),
 			      NULL, NULL,
-			      g_cclosure_marshal_VOID__POINTER,
+			      g_cclosure_marshal_VOID__BOXED,
 			      G_TYPE_NONE,
 			      1,
-			      G_TYPE_POINTER);
+			      G_TYPE_ERROR);
 
 	gth_task_signals[PROGRESS] =
 		g_signal_new ("progress",