Issue 5142 - Convert Element Hiding to C++

compiled/ElemHide.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/>.
  */
 
 /**
  * @fileOverview Element hiding implementation.
  */
 
-#include <unordered_map>
+#pragma once
+
 #include <vector>
 
 #include "bindings/runtime.h"
 #include "intrusive_ptr.h"
 #include "StringMap.h"
 #include "filter/Filter.h"
 #include "filter/ElemHideBase.h"
 #include "filter/ElemHideException.h"
 
-class _ElemHide_SelectorList : public ref_counted
+class ElemHide_SelectorList : public ref_counted
 {
   std::vector<ElemHideBasePtr> mSelectors;
 public:
   size_t BINDINGS_EXPORTED GetSelectorCount() const
   {
     return mSelectors.size();
   }
-  DependentString BINDINGS_EXPORTED SelectorAt(size_t idx) const;
+  OwnedString BINDINGS_EXPORTED SelectorAt(size_t idx) const;
   const String& BINDINGS_EXPORTED FilterKeyAt(size_t idx) const;
 
-  void push_back(ElemHideBasePtr filter)
+  void push_back(const ElemHideBasePtr& filter)
   {
     mSelectors.push_back(filter);
+  }
+
+  void append(const ElemHide_SelectorList& list)
+  {
+    mSelectors.insert(mSelectors.end(),
+                      list.mSelectors.cbegin(), list.mSelectors.cend());
   }
 };
 
 class ElemHide : public ref_counted
 {
   // All filters. Key is filter text. Exception filters excluded.
   StringMap<ElemHideBasePtr> mFilters;
-  // StringMap is non copyable. std::unordered_map<> it is
-  // Filters by domain. Key is domain. Subkey is filter text.
-  StringMap<std::unordered_map<DependentString,ElemHideBasePtr,StringHash>> mFiltersByDomain;

[hub, 2017/10/25 01:19:38]

Using an std::unordered_map. Bu if we make StringMap movable we should be able
to use it here.

[sergei, 2018/01/15 15:31:15]

What is the overhead from the std::unordered_map? As far as I remember we didn't
use it because it contributed really a lot into the generated JS code.
I think we should make StringMap movable, though probably entry of the container
should be movable what can also optimize resize method of the container. Maybe
implement it as another issue?

[hub, 2018/01/19 02:11:01]

File https://issues.adblockplus.org/ticket/6279 to make Map<> moveable.

+  // Filters by domain. Key is domain.
+  // In value key is filter text, value is filter or NULL
+  OwnedStringMap<OwnedStringMap<ElemHideBasePtr>> mFiltersByDomain;
 
   // Exceptions. The key is the selector.
-  StringMap<std::vector<ElemHideExceptionPtr>> mExceptions;
+  OwnedStringMap<std::vector<ElemHideExceptionPtr>> mExceptions;
   // Known exceptions. Filter text as keys.
   StringSet mKnownExceptions;
 
-  // Unconditional selectors. Filter text as key
-  StringSet mUnconditionalSelectors;
+  // Unconditional selectors. Filter selector as key. Filter as value.
+  OwnedStringMap<ElemHideBasePtr> mUnconditionalSelectors;
 
-  static ElemHide* mInstance;
+  mutable intrusive_ptr<ElemHide_SelectorList> mUnconditionalSelectorsCache;
+
 public:
+  static ElemHide* BINDINGS_EXPORTED Create()
+  {
+    return new ElemHide();
+  }
+  // Used by GetSelectorsForDomain to narrow down selectors to return.
+  // Keep these value up to date in the ElemHide.js import script.
   enum Criteria
   {
+    // Return all selectors applying to a particular hostname.
     ALL_MATCHING = 0,
+    // Exclude selectors which apply to all websites without exception.
     NO_UNCONDITIONAL = 1,
+    // Return only selectors for filters which specifically match the
+    // given host name.
     SPECIFIC_ONLY = 2,
   };
-
-  static ElemHide* BINDINGS_EXPORTED GetInstance()
-  {
-    return mInstance;
-  }
 
   void BINDINGS_EXPORTED Clear();
   void BINDINGS_EXPORTED Add(ElemHideBase& filter);
   void BINDINGS_EXPORTED Remove(ElemHideBase& filter);
 
-  _ElemHide_SelectorList* BINDINGS_EXPORTED GetSelectorsForDomain(const String& domain, Criteria criteria) const;
-  _ElemHide_SelectorList* BINDINGS_EXPORTED GetUnconditionalSelectors() const;
+  ElemHide_SelectorList* BINDINGS_EXPORTED GetSelectorsForDomain(const String& domain,
+                                                                 Criteria criteria) const;
+  ElemHide_SelectorList* BINDINGS_EXPORTED GetUnconditionalSelectors() const;
 
   ElemHideException* BINDINGS_EXPORTED GetException(const ElemHideBase& filter,

[hub, 2017/10/25 01:19:38]

This function is needed until ElemHideEmulation is modified to not use it.

                                                     DependentString& docDomain) const;
 
 private:
-  void AddToFiltersByDomain(ElemHideBase& filter);
+  void AddToFiltersByDomain(const ElemHideBasePtr & filter);
 };