Issue 5146 - Part 2: Process http response in C++

compiled/subscription/DownloadableSubscription.h

 /*
  * 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 52 matching lines @@
   static DownloadableSubscription_Parser* BINDINGS_EXPORTED ParseDownload();
   OwnedString BINDINGS_EXPORTED Serialize() const;
 };
 
 typedef intrusive_ptr<DownloadableSubscription> DownloadableSubscriptionPtr;
 
 class DownloadableSubscription_Parser : public ref_counted
 {
   std::vector<OwnedString> mFiltersText;
   OwnedStringMap<OwnedString> mParams;
-  bool mFirstLine;
 public:
   DownloadableSubscription_Parser();
-  void BINDINGS_EXPORTED Process(const String& line);
+  bool BINDINGS_EXPORTED Process(const String& buffer);
   bool BINDINGS_EXPORTED VerifyChecksum();
   // return the expiration interval.
   int64_t BINDINGS_EXPORTED Finalize(DownloadableSubscription&);
   const String& BINDINGS_EXPORTED GetRedirect() const;
   const String& BINDINGS_EXPORTED GetHomepage() const;
+  const String& BINDINGS_EXPORTED GetError() const
+  {
+    return mError;
+  }
 private:
   MD5 mChecksum;
+  DependentString mError;
+  OwnedString mRequiredVersion;
   OwnedString mB64Checksum;
   static int64_t ParseExpires(const String& expires);
+  bool ProcessFirstLine(const String& line);
+  void ProcessLine(const String& line);
+  static bool GetNextLine(DependentString& buffer, DependentString& line);
 };