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

compiled/Filter.h

-#ifndef ADBLOCKPLUS_FILTER_H
-#define ADBLOCKPLUS_FILTER_H
+#pragma once
 
-#include <string>
 #include <vector>
 
-class Filter
+#include "String.h"
+#include "intrusive_ptr.h"
+#include "debug.h"
+
+class Filter : public ref_counted
 {
-private:
-  std::u16string text;
+protected:
+  OwnedString mText;
 
 public:
-  Filter(const std::u16string& text);
-
-  /* TODO
-  std::vector<Subscription> subscriptions;
-  */
-
-  const std::u16string get_text() {return text;}
-
   enum Type
   {
     UNKNOWN = 0,
     INVALID = 1,
     COMMENT = 2,
     BLOCKING = 3,
     WHITELIST = 4,
     ELEMHIDE = 5,
     ELEMHIDEEXCEPTION = 6,
     CSSPROPERTY = 7,
   };
 
-  virtual Type get_type() = 0;
+  explicit Filter(Type type, const String& text);
+  ~Filter();
 
-  virtual const std::u16string Serialize();
+  Type mType;
+
+  /* TODO
+  std::vector<Subscription> mSubscriptions;
+  */
+
+  EMSCRIPTEN_KEEPALIVE const String& GetText() const
+  {
+    return mText;
+  }
+
+  EMSCRIPTEN_KEEPALIVE OwnedString Serialize() const;
+
+  static EMSCRIPTEN_KEEPALIVE Filter* FromText(DependentString& text);
 };
 
-#endif
+typedef intrusive_ptr<Filter> FilterPtr;