Issue 4125 - [emscripten] Convert filter classes to C++

compiled/Filter.h

+#pragma once
+
+#include <vector>
+
+#include "String.h"
+#include "intrusive_ptr.h"
+#include "debug.h"
+
+class Filter : public ref_counted
+{
+protected:
+  OwnedString mText;
+
+public:
+  explicit Filter(const String& text);
+  virtual ~Filter();
+
+  /* TODO
+  std::vector<Subscription> subscriptions;

[sergei, 2016/06/16 21:16:36]

May be it makes sense to remove this comment from here.

Just wonder, why do we need to have several subscriptions as a member of Filter
object? It seems it should be vice versa, subscription should have a set of
filters.

[Wladimir Palant, 2016/12/06 10:47:28]

This is merely a reverse mapping meant to speed up lookups. E.g. when a filter
is added it's important to know what subscriptions it belongs to and whether
these are enabled or disabled.

+  */
+
+  EMSCRIPTEN_KEEPALIVE const String& GetText() const
+  {
+    return mText;
+  }
+
+  enum Type
+  {
+    UNKNOWN = 0,
+    INVALID = 1,
+    COMMENT = 2,
+    BLOCKING = 3,
+    WHITELIST = 4,
+    ELEMHIDE = 5,
+    ELEMHIDEEXCEPTION = 6,
+    CSSPROPERTY = 7,
+  };
+
+  virtual Type GetType() const = 0;

[sergei, 2016/06/16 21:16:34]

Can we set filter type in constructor and make this method non virtual? It
should reduce the amount of code and it should not actually add any overhead.

[Wladimir Palant, 2016/12/06 10:47:26]

Actually, if we do that then we can just read out the filter type member from
JavaScript - this will save some overhead. I implemented it this way now.

+
+  EMSCRIPTEN_KEEPALIVE OwnedString Serialize() const;
+
+  static EMSCRIPTEN_KEEPALIVE Type GetType(Filter* filter)
+  {
+    return filter->GetType();
+  }
+
+  static EMSCRIPTEN_KEEPALIVE Filter* FromText(DependentString& text);
+  static EMSCRIPTEN_KEEPALIVE Filter* GetKnownFilter(const String& text);
+};
+
+typedef intrusive_ptr<Filter> FilterPtr;