Only use an icon if it passes some sanity checks

deluge/ui/tracker_icons.py

@@ -315,10 +315,34 @@ class TrackerIcons(Component):
         (url, mimetype) = icons.pop(0)
         d = download_file(url, os.path.join(self.dir, host_to_icon_name(host, mimetype)),
                           force_filename=True)
+        d.addCallback(self.check_icon_is_valid)
         if icons:
             d.addErrback(self.on_download_icon_fail, host, icons)
         return d
 
+    @proxy(threads.deferToThread)
+    def check_icon_is_valid(self, icon_name):
+        """
+        Performs a sanity check on icon_name
+
+        :param icon_name: the name of the icon to check
+        :type icon_name: string
+        :returns: the name of the validated icon
+        :rtype: string
+        :raises: InvalidIconError
+        """
+
+        if PIL_INSTALLED:
+            try:
+                Image.open(icon_name)
+            except IOError, e:
+                raise InvalidIconError(e)
+        else:
+            if os.stat(icon_name).st_size == 0L:
+                raise InvalidIconError, "empty icon"
+
+        return icon_name
+
     def on_download_icon_complete(self, icon_name, host):
         """
         Runs any download cleanup functions
@@ -547,3 +571,6 @@ def extension_to_mimetype(extension):
 
 class NoIconsError(Exception):
     pass
+
+class InvalidIconError(Exception):
+    pass

tests/test_tracker_icons.py

@@ -63,5 +63,5 @@ class TrackerIconsTestCase(unittest.TestCase):
 
     def test_get_empty_string_tracker(self):
         d = icons.get("")
-        d.addCallback(self.assertEquals, None)
+        d.addCallback(self.assertIdentical, None)
         return d