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

compiled/ElemHideBase.h

-#ifndef ADBLOCKPLUS_ELEMHIDEBASE_H
-#define ADBLOCKPLUS_ELEMHIDEBASE_H
+#pragma once
 
 #include <cstddef>
-#include <string>
 
 #include "ActiveFilter.h"
 
+struct ElemHideBaseData
+{
+  String::size_type mDomainsEnd;
+  String::size_type mSelectorStart;
+
+  bool HasDomains() const
+  {
+    return mDomainsEnd != 0;
+  }
+
+  DependentString GetDomainsSource(String& text) const
+  {
+    return DependentString(text, 0, mDomainsEnd);
+  }
+
+  const DependentString GetDomainsSource(const String& text) const
+  {
+    return DependentString(text, 0, mDomainsEnd);
+  }
+
+  DependentString GetSelector(String& text) const
+  {
+    return DependentString(text, mSelectorStart);
+  }
+
+  const DependentString GetSelector(const String& text) const
+  {
+    return DependentString(text, mSelectorStart);
+  }
+};
+
+struct ElemHideData;
+
 class ElemHideBase : public ActiveFilter
 {
+protected:
+  ElemHideBaseData mData;
 public:
-  ElemHideBase(const std::u16string& text, size_t domainsEnd, size_t selectorStart);
-  static Type Parse(const std::u16string& text, size_t* domainsEnd, size_t* selectorStart);
-  static ElemHideBase* Create(const std::u16string& text);
+  explicit ElemHideBase(Type type, const String& text, const ElemHideBaseData& data);
+  static Type Parse(DependentString& text, ElemHideData& data);
+
+  EMSCRIPTEN_KEEPALIVE const DependentString GetSelector() const
+  {
+    return mData.GetSelector(mText);
+  }
+
+  EMSCRIPTEN_KEEPALIVE OwnedString GetSelectorDomain() const;
 };
-
-#endif