Filter changed callback

lib/filterUpdateRegistration.js

Index: lib/filterUpdateRegistration.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/lib/filterUpdateRegistration.js
@@ -0,0 +1,45 @@
+/*
+ * This file is part of Adblock Plus <http://adblockplus.org/>,
+ * Copyright (C) 2006-2013 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+let {FilterNotifier} = require("filterNotifier");
+let {Synchronizer} = require("synchronizer");
+
+FilterNotifier.addListener(function(action, subscription)
+{
+  switch (action)

[Andrey Novikov, 2013/06/18 11:48:28]

I didn't change the logic of the current Android application. May be it has to
be modified in some way to be more uniform?

[Wladimir Palant, 2013/06/18 15:02:15]

Yes, this definitely needs to be more generic - this is a general-purpose
library. One way to would be sending all status changes to the C++ code. That's
likely unnecessary overhead however, there can be lots of messages. The other
option is passing in a filter - what messages should be sent to the caller. You
will need to add a function to api.js - C++ doesn't run any complicated JS code.
The list of messages definitely shouldn't be hardcoded here.

[Andrey Novikov, 2013/06/25 08:08:02]

So, I see no reason to complicate things with some filter, C code can deal with
filtering by itself. Yes?

[Felix Dahlke, 2013/06/25 08:21:58]

IMO yes. It's simpler, and I doubt there'll be any noteworthy overhead if we
just forward all events.

[Wladimir Palant, 2013/06/25 08:44:40]

JS to C++ calls always mean overhead and we will be producing lots of them here.
Still, probably not worth it unless we see that this indeed has a performance
impact.

+  {
+    case "subscription.lastDownload":
+    case "subscription.downloadStatus":
+      let status = "synchronize_never";
+      let time = 0;
+      if (Synchronizer.isExecuting(subscription.url))
+      {
+        status = "synchronize_in_progress";
+      }
+      else if (subscription.downloadStatus && subscription.downloadStatus != "synchronize_ok")
+      {
+        status = subscription.downloadStatus;
+      }
+      else if (subscription.lastDownload > 0)
+      {
+        time = subscription.lastDownload;
+        status = "synchronize_last_at";
+      }

[Wladimir Palant, 2013/06/18 15:02:15]

This processing should be done in the C++ code, the code here should just send
the parameters unchanged.

+      _triggerEvent("filterChange", subscription.url, status, time);
+      break;
+  }
+});