Alter return value to -1 for invalid freespace path

Updated GTK and Web UI to display error if value is -1
Added set_markup method to gtk statusbaritem class

deluge/core/core.py

@@ -858,7 +858,7 @@ class Core(component.Component):
         try:
             return deluge.common.free_space(path)
         except InvalidPathError:
-            return 0
+            return -1
 
     @export
     def get_libtorrent_version(self):

deluge/tests/test_core.py

@@ -175,7 +175,7 @@ class CoreTestCase(unittest.TestCase):
         space = self.core.get_free_space(".")
         self.assertTrue(type(space) in (int, long))
         self.assertTrue(space >= 0)
-        self.assertEquals(self.core.get_free_space("/someinvalidpath"), 0)
+        self.assertEquals(self.core.get_free_space("/someinvalidpath"), -1)
 
     def test_test_listen_port(self):
         d = self.core.test_listen_port()

deluge/ui/gtkui/statusbar.py

@@ -96,6 +96,10 @@ class StatusBarItem:
         if self._label.get_text() != text:
             self._label.set_text(text)
 
+    def set_markup(self, text):
+        if self._label.get_label() != text:
+            self._label.set_markup(text)
+
     def set_tooltip(self, tip):
         if self._ebox.get_tooltip_text() != tip:
             self._ebox.set_tooltip_text(tip)
@@ -327,7 +331,10 @@ class StatusBar(component.Component):
                 self.remove_item(self.health_item)
 
     def _on_get_free_space(self, space):
-        self.diskspace_item.set_text(deluge.common.fsize(space))
+        if space >= 0:
+            self.diskspace_item.set_text(deluge.common.fsize(space))
+        else:
+            self.diskspace_item.set_markup("<span foreground=\"red\">" + _("Error") + "</span>")
 
     def _on_max_download_speed(self, max_download_speed):
         self.max_download_speed = max_download_speed

deluge/ui/web/js/deluge-all/Statusbar.js

@@ -310,6 +310,6 @@ Deluge.Statusbar = Ext.extend(Ext.ux.StatusBar, {
         });
 
         this.items.get('statusbar-dht').setText(stats.dht_nodes);
-        this.items.get('statusbar-freespace').setText(fsize(stats.free_space));
+        this.items.get('statusbar-freespace').setText(stats.free_space >= 0 ? fsize(stats.free_space): _("Error"));
     }
 });