Issue 5143 - Convert ElemHideEmulation to C++

compiled/ElemHideEmulation.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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #pragma once
 
 #include <vector>
 
 #include "bindings/runtime.h"
 #include "intrusive_ptr.h"
 #include "filter/ElemHideBase.h"
 
-class _ElemHideEmulation_FilterList : public ref_counted

[sergei, 2017/11/16 09:58:07]

IMO it's not a good idea to have names starting with underscore in C++. Could
you please rename it?

[hub, 2017/11/20 19:16:01]

That was part of the "spec" but indeed it conflict with C++.

+class ElemHide;
+
+class ElemHideEmulation_FilterList : public ref_counted
 {
   std::vector<ElemHideBasePtr> mFilters;
 public:
   size_t BINDINGS_EXPORTED GetFilterCount() const
   {
     return mFilters.size();
   }
-  ElemHideBase* BINDINGS_EXPORTED FilterAt(size_t idx)
+
+  ElemHideBase* BINDINGS_EXPORTED FilterAt(size_t index)
   {
-    return mFilters[idx].get();
+    if (index >= mFilters.size())
+      return nullptr;
+
+    ElemHideBasePtr result(mFilters[index]);
+    return result.release();
   }
 
-  void push_back(ElemHideBasePtr filter)

[sergei, 2017/11/16 09:58:07]

What about using r-value or l-value reference here?

[hub, 2017/11/20 19:16:01]

r-value is impossible: we don't want to move the value. (also fails to compile).
const l-value is fine.

[sergei, 2018/01/25 16:04:00]

Acknowledged. Perhaps we should revisit such methods later and create both
versions.

[hub, 2018/01/25 19:05:26]

Looking at the use case, move doesn't make sense here. We sure can revisit it if
the need arises.

+  void push_back(const ElemHideBasePtr& filter)
   {
     mFilters.push_back(filter);
   }
 
 };
 
 class ElemHideEmulation : public ref_counted
 {
   StringMap<ElemHideBasePtr> mFilters;
 
-  static ElemHideEmulation* mInstance;
-
 public:
-  static ElemHideEmulation* BINDINGS_EXPORTED GetInstance()

[sergei, 2017/11/16 09:58:07]

IMO the growth of usage of the singleton pattern is getting really dangerous.
Can we stop doing it?

[hub, 2017/11/20 19:16:00]

yes.

+  static ElemHideEmulation* BINDINGS_EXPORTED Create()
   {
-    return mInstance;
+    return new ElemHideEmulation();
   }
 
   void BINDINGS_EXPORTED Add(ElemHideBase&);
   void BINDINGS_EXPORTED Remove(ElemHideBase&);
   void BINDINGS_EXPORTED Clear();
-  _ElemHideEmulation_FilterList* BINDINGS_EXPORTED GetRulesForDomain(DependentString&);
+  ElemHideEmulation_FilterList* BINDINGS_EXPORTED GetRulesForDomain(const ElemHide&, DependentString&);
 };