Add API calls and stubs for filter matching and subscription management

include/AdblockPlus/FilterEngine.h

+#include <vector>
+#include <string>
+
+namespace AdblockPlus
+{
+    class JsEngine;
+
+    struct Subscription
+    {
+        std::string url;
+        std::string title;

[Wladimir Palant, 2013/04/03 13:42:41]

We'll need to expose many more subscription properties like last download time.
I wonder whether it's better to just wrap a JS object here and provide a
GetProperty() method (and a corresponding SetPropery() method to set things like
title). It will also make converting from the C++ object to the JS object
simpler.

[Felix Dahlke, 2013/04/04 05:10:52]

Sure, sounds reasonable. My intention was to go with the bare minimum we need on
the UI for now and expand as needed, but a general GetPropery mechanism would
allow for that as well.

+
+        Subscription(const std::string& url, const std::string& title);
+    };
+
+    class FilterEngine
+    {
+    public:
+        explicit FilterEngine(JsEngine& jsEngine);
+        void AddSubscription(Subscription subscription);
+        void RemoveSubscription(const Subscription& subscription);
+        const Subscription* FindSubscription(const std::string& url) const;

[Wladimir Palant, 2013/04/03 13:42:41]

This should be called GetSubscription() - ABP code will generally create a new
subscription object for a URL if there isn't one yet, it allows doing something
with the subscription before actually adding it.

[Felix Dahlke, 2013/04/04 05:10:52]

Oh, didn't notice. Sure :)

+        const std::vector<Subscription>& GetSubscriptions() const;
+        void UpdateSubscriptionFilters(const Subscription& subscription);
+        std::vector<Subscription> FetchAvailableSubscriptions();

[Wladimir Palant, 2013/04/03 13:42:41]

This is usually an asynchronous action (via XMLHttpRequest), we probably want to
work with callbacks here.

[Felix Dahlke, 2013/04/04 05:10:52]

Yeah, not sure why I didn't do that actually...

+        bool Matches(const std::string& url,
+                     const std::string& contentType) const;

[Wladimir Palant, 2013/04/03 13:42:41]

We need to pass documentUrl as well here at the very least - this is required to
handle whitelisting and domain-specific filters correctly.

[Felix Dahlke, 2013/04/04 05:10:52]

You're right, it's quite lacking. I had the idea to go with the absolute bare
minimum for now, and expand as needed (not being entirely sure yet what kind of
information we can actually get), but we can just wrap it properly right now.

+        std::vector<std::string> GetElementHidingRules() const;
+
+    private:
+        JsEngine& jsEngine;
+        std::vector<Subscription> subscriptions;
+    };
+}

[Wladimir Palant, 2013/04/03 13:42:41]

General note: maybe Subscription should be a class that only FilterEngine can
create, via GetSubscription(). It would have a private constructor and get the
JS engine as a parameter there. Things like UpdateFilters() could be methods of
the Subscription class then, also AddToList() and RemoveFromList() - so you
wouldn't have to list each method working with subscriptions in FilterEngine.

[Felix Dahlke, 2013/04/04 05:10:52]

Yes, that would be a nicer design. As I noted before, my intention was to keep
all this as simple as possible for now, but there's no need to now that you're
back and Oleksandr has begun to integrate it.