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

compiled/ElemHideBase.h

-#ifndef ADBLOCK_PLUS_ELEM_HIDE_BASE_H
-#define ADBLOCK_PLUS_ELEM_HIDE_BASE_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
 {
-private:
-  std::u16string selector;
+protected:
+  ElemHideBaseData mData;
 public:
-  ElemHideBase(const std::u16string& text, const std::u16string& domains,
-      const std::u16string& selector);
-  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);
 
-  const std::u16string GetSelector() const
+  EMSCRIPTEN_KEEPALIVE const DependentString GetSelector() const
   {
-    return selector;
+    return mData.GetSelector(mText);
   }
 
-  const std::u16string GetSelectorDomain() const;
+  EMSCRIPTEN_KEEPALIVE OwnedString GetSelectorDomain() const;
 };
-
-#endif