[gthumb] do not call gth_file_source_monitor_directory if the location is NULL

[Paolo Bacchilega <paobac src gnome org>]

commit 1ddb2daf17503ba93258e75e872aa996523e7be7
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Mon Apr 23 19:05:51 2012 +0200

    do not call gth_file_source_monitor_directory if the location is NULL

 gthumb/gth-browser.c     |    7 ++++---
 gthumb/gth-file-source.c |    2 ++
 2 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/gthumb/gth-browser.c b/gthumb/gth-browser.c
index e382be1..b92c32f 100644
--- a/gthumb/gth-browser.c
+++ b/gthumb/gth-browser.c
@@ -1867,9 +1867,10 @@ _gth_browser_load (GthBrowser *browser,
 	case GTH_ACTION_GO_UP:
 	case GTH_ACTION_VIEW:
 		if (browser->priv->location_source != NULL) {
-			gth_file_source_monitor_directory (browser->priv->location_source,
-							   browser->priv->monitor_location,
-							   FALSE);
+			if (browser->priv->monitor_location != NULL)
+				gth_file_source_monitor_directory (browser->priv->location_source,
+								   browser->priv->monitor_location,
+								   FALSE);
 			_g_clear_object (&browser->priv->location_source);
 			_g_clear_object (&browser->priv->monitor_location);
 		}
diff --git a/gthumb/gth-file-source.c b/gthumb/gth-file-source.c
index 49899a5..dea8567 100644
--- a/gthumb/gth-file-source.c
+++ b/gthumb/gth-file-source.c
@@ -1300,6 +1300,8 @@ gth_file_source_monitor_directory (GthFileSource *file_source,
 				   GFile         *file,
 				   gboolean       activate)
 {
+	g_return_if_fail (file != NULL);
+
 	GTH_FILE_SOURCE_GET_CLASS (G_OBJECT (file_source))->monitor_directory (file_source, file, activate);
 }