Issue 5142 - Convert Element Hiding to C++

compiled/ElemHide.h

Index: compiled/ElemHide.h
===================================================================
new file mode 100644
--- /dev/null
+++ b/compiled/ElemHide.h
@@ -0,0 +1,92 @@
+/*
+ * 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>
+#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
+{
+  std::vector<ElemHideBasePtr> mSelectors;
+public:
+  size_t BINDINGS_EXPORTED GetSelectorCount() const
+  {
+    return mSelectors.size();
+  }
+  DependentString BINDINGS_EXPORTED SelectorAt(size_t idx) const;
+  const String& BINDINGS_EXPORTED FilterKeyAt(size_t idx) const;
+
+  void push_back(ElemHideBasePtr filter)
+  {
+    mSelectors.push_back(filter);
+  }
+};
+
+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.

+
+  // Exceptions. The key is the selector.
+  StringMap<std::vector<ElemHideExceptionPtr>> mExceptions;
+  // Known exceptions. Filter text as keys.
+  StringSet mKnownExceptions;
+
+  // Unconditional selectors. Filter text as key
+  StringSet mUnconditionalSelectors;
+
+  static ElemHide* mInstance;
+public:
+  enum Criteria
+  {
+    ALL_MATCHING = 0,
+    NO_UNCONDITIONAL = 1,
+    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;
+
+  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);
+};
+