[nautilus] Support unsetting metadata

[Alexander Larsson <alexl src gnome org>]

commit 7874f2d9422618107edabd7056b7167844c389ca
Author: Alexander Larsson <alexl redhat com>
Date:   Thu Jun 25 09:23:27 2009 +0200

    Support unsetting metadata

 libnautilus-private/nautilus-file.c |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)
---
diff --git a/libnautilus-private/nautilus-file.c b/libnautilus-private/nautilus-file.c
index 235e26a..5c478d0 100644
--- a/libnautilus-private/nautilus-file.c
+++ b/libnautilus-private/nautilus-file.c
@@ -3291,13 +3291,15 @@ nautilus_file_set_metadata (NautilusFile *file,
 		val = default_metadata;
 	}
 
-	if (val == NULL) {
-		g_print ("TODO: setting NULL string metadata");
-		val = "<null>";
-	}
-
 	gio_key = g_strconcat ("metadata::", key, NULL);
-	g_file_info_set_attribute_string (info, gio_key, val);
+	if (val != NULL) {
+		g_file_info_set_attribute_string (info, gio_key, val);
+	} else {
+		/* Unset the key */
+		g_file_info_set_attribute (info, gio_key,
+					   G_FILE_ATTRIBUTE_TYPE_INVALID,
+					   NULL);
+	}
 	g_free (gio_key);
 
 	location = nautilus_file_get_location (file);