Issue 5141 - [emscripten] Convert filter matcher to C++

compiled/filter/RegExpFilter.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 292 matching lines @@
   }
 
   data.mPatternEnd = text.find(u'$', data.mPatternStart);
   if (data.mPatternEnd == text.npos)
     data.mPatternEnd = text.length();
 
   ParseOptions(text, error, data, data.mPatternEnd + 1);
   if (!error.empty())
     return Type::INVALID;
 
+  data.mRegexpId = -1;
   if (data.mPatternEnd - data.mPatternStart >= 2 &&
       text[data.mPatternStart] == u'/' &&
       text[data.mPatternEnd - 1] == u'/')
   {
-    data.SetRegExp(GenerateRegExp(DependentString(text, data.mPatternStart + 1,
-        data.mPatternEnd - data.mPatternStart - 2), data.mMatchCase));
+    data.mRegexpId = GenerateRegExp(DependentString(text,
+        data.mPatternStart + 1, data.mPatternEnd - data.mPatternStart - 2),
+        data.mMatchCase);
     if (data.mRegexpId == -1)
     {
       error.reset(u"filter_invalid_regexp"_str);
       return Type::INVALID;
     }
   }
 
   return type;
 }
 
@@ skipping 54 matching lines @@
   if (!(mData.mContentType & typeMask) ||
       (mData.mThirdParty == TrippleState::YES && !thirdParty) ||
       (mData.mThirdParty == TrippleState::NO && thirdParty) ||
       !IsActiveOnDomain(docDomain, sitekey))
   {
     return false;
   }
 
   if (!mData.RegExpParsingDone())
   {
     const OwnedString pattern(mData.GetRegExpSource(mText));

[sergei, 2017/10/18 10:58:42]

BTW, `pattern` should be a DependentString there is no need in additional
copying of it, GetRegExpSource returns DependentString.

-    mData.SetRegExp(GenerateRegExp(RegExpFromSource(pattern), mData.mMatchCase));
+    mData.mRegexpId = GenerateRegExp(RegExpFromSource(pattern), mData.mMatchCase);
   }
   return TestRegExp(mData.mRegexpId, location);
 }