Remove RefPtrHashMap

The recently added 'HashTraits::PeekInType' type allows us to remove
HashMap<RefPtr..> template specialization without loosing the efficiency
and without bringing any significant changes and complexity to the HashMap
class.

To get rid of 'RefPtrHashMap' a new 'RefPtrValuePeeker' type was created
and used as 'HashTraits::PeekInType' for RefPtr. The 'RefPtrValuePeeker'
class can be constructed either from RefPtr, PassRefPtr or a plain pointer,
then it behaves like a plain pointer itself within HashTable methods.

The proposed change brings the following benefits:
1) Removes tons of duplicated code
2) Allows avoiding ref-count churn also at HashSet<RefPtr>

Review URL: https://codereview.chromium.org/184233006

git-svn-id: svn://svn.chromium.org/blink/trunk@168593 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/wtf/HashMap.h

@@ -526,6 +526,4 @@ namespace WTF {
 
 using WTF::HashMap;
 
-#include "wtf/RefPtrHashMap.h"
-
 #endif /* WTF_HashMap_h */

third_party/WebKit/Source/wtf/HashTraits.h

@@ -170,7 +170,7 @@ namespace WTF {
         static const bool hasIsEmptyValueFunction = true;
         static bool isEmptyValue(const RefPtr<P>& value) { return !value; }
 
-        typedef const RefPtr<P>& PeekInType;
+        typedef RefPtrValuePeeker<P> PeekInType;
         typedef RefPtr<P>* IteratorGetType;
         typedef const RefPtr<P>* IteratorConstGetType;
         typedef RefPtr<P>& IteratorReferenceType;

third_party/WebKit/Source/wtf/RefPtr.h

@@ -188,6 +188,16 @@ namespace WTF {
         return p.get();
     }
 
+    template<typename T> class RefPtrValuePeeker {
+    public:
+        ALWAYS_INLINE RefPtrValuePeeker(T* p): m_ptr(p) { }
+        template<typename U> RefPtrValuePeeker(const RefPtr<U>& p): m_ptr(p.get()) { }
+        template<typename U> RefPtrValuePeeker(const PassRefPtr<U>& p): m_ptr(p.get()) { }
+        ALWAYS_INLINE operator T*() const { return m_ptr; }
+    private:
+        T* m_ptr;
+    };
+
 } // namespace WTF
 
 using WTF::RefPtr;

third_party/WebKit/Source/wtf/RefPtrHashMap.h

-/*
- * Copyright (C) 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public License
- * along with this library; see the file COPYING.LIB.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301, USA.
- *
- */
-
-#ifndef RefPtrHashMap_h
-#define RefPtrHashMap_h
-
-#include "wtf/DefaultAllocator.h"
-
-namespace WTF {
-
-    // This specialization is a copy of HashMap for use with RefPtr keys, with overloaded functions
-    // to allow for lookup by pointer instead of RefPtr, avoiding ref-count churn.
-
-     // FIXME: Find a way to do this with traits that doesn't require a copy of the HashMap template.
-
-    template<typename T, typename MappedArg, typename HashArg, typename KeyTraitsArg, typename MappedTraitsArg>
-    class HashMap<RefPtr<T>, MappedArg, HashArg, KeyTraitsArg, MappedTraitsArg, DefaultAllocator> {
-    private:
-        typedef KeyTraitsArg KeyTraits;
-        typedef MappedTraitsArg MappedTraits;
-        typedef KeyValuePairHashTraits<KeyTraits, MappedTraits> ValueTraits;
-
-    public:
-        typedef typename KeyTraits::TraitType KeyType;
-        typedef T* RawKeyType;
-        typedef typename MappedTraits::TraitType MappedType;
-        typedef typename ValueTraits::TraitType ValueType;
-
-    private:
-        typedef typename MappedTraits::PassInType MappedPassInType;
-        typedef typename MappedTraits::PassOutType MappedPassOutType;
-        typedef typename MappedTraits::PeekOutType MappedPeekType;
-
-        typedef typename ReferenceTypeMaker<MappedPassInType>::ReferenceType MappedPassInReferenceType;
-
-        typedef HashArg HashFunctions;
-
-        typedef HashTable<KeyType, ValueType, KeyValuePairKeyExtractor,
-            HashFunctions, ValueTraits, KeyTraits, DefaultAllocator> HashTableType;
-
-        typedef HashMapTranslator<ValueTraits, HashFunctions>
-            Translator;
-
-    public:
-        typedef HashTableIteratorAdapter<HashTableType, ValueType> iterator;
-        typedef HashTableConstIteratorAdapter<HashTableType, ValueType> const_iterator;
-        typedef typename HashTableType::AddResult AddResult;
-
-        void swap(HashMap&);
-
-        unsigned size() const;
-        unsigned capacity() const;
-        bool isEmpty() const;
-
-        // iterators iterate over pairs of keys and values
-        iterator begin();
-        iterator end();
-        const_iterator begin() const;
-        const_iterator end() const;
-
-        iterator find(const KeyType&);
-        iterator find(RawKeyType);
-        const_iterator find(const KeyType&) const;
-        const_iterator find(RawKeyType) const;
-        bool contains(const KeyType&) const;
-        bool contains(RawKeyType) const;
-        MappedPeekType get(const KeyType&) const;
-        MappedPeekType get(RawKeyType) const;
-        MappedPeekType inlineGet(RawKeyType) const;
-
-        // replaces value but not key if key is already present
-        // return value is a pair of the iterator to the key location,
-        // and a boolean that's true if a new value was actually added
-        AddResult set(const KeyType&, MappedPassInType);
-        AddResult set(RawKeyType, MappedPassInType);
-
-        // does nothing if key is already present
-        // return value is a pair of the iterator to the key location,
-        // and a boolean that's true if a new value was actually added
-        AddResult add(const KeyType&, MappedPassInType);
-        AddResult add(RawKeyType, MappedPassInType);
-
-        void remove(const KeyType&);
-        void remove(RawKeyType);
-        void remove(iterator);
-        void clear();
-
-        MappedPassOutType take(const KeyType&); // efficient combination of get with remove
-        MappedPassOutType take(RawKeyType); // efficient combination of get with remove
-
-    private:
-        AddResult inlineAdd(const KeyType&, MappedPassInReferenceType);
-        AddResult inlineAdd(RawKeyType, MappedPassInReferenceType);
-
-        HashTableType m_impl;
-    };
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline void HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::swap(HashMap& other)
-    {
-        m_impl.swap(other.m_impl);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline unsigned HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::size() const
-    {
-        return m_impl.size();
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline unsigned HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::capacity() const
-    {
-        return m_impl.capacity();
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline bool HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::isEmpty() const
-    {
-        return m_impl.isEmpty();
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::iterator HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::begin()
-    {
-        return m_impl.begin();
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::iterator HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::end()
-    {
-        return m_impl.end();
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::const_iterator HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::begin() const
-    {
-        return m_impl.begin();
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::const_iterator HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::end() const
-    {
-        return m_impl.end();
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::iterator HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::find(const KeyType& key)
-    {
-        return m_impl.find(key);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::iterator HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::find(RawKeyType key)
-    {
-        return m_impl.template find<Translator>(key);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::const_iterator HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::find(const KeyType& key) const
-    {
-        return m_impl.find(key);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::const_iterator HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::find(RawKeyType key) const
-    {
-        return m_impl.template find<Translator>(key);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline bool HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::contains(const KeyType& key) const
-    {
-        return m_impl.contains(key);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline bool HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::contains(RawKeyType key) const
-    {
-        return m_impl.template contains<Translator>(key);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::AddResult
-    HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::inlineAdd(const KeyType& key, MappedPassInReferenceType mapped)
-    {
-        return m_impl.template add<Translator>(key, mapped);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::AddResult
-    HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::inlineAdd(RawKeyType key, MappedPassInReferenceType mapped)
-    {
-        return m_impl.template add<Translator>(key, mapped);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::AddResult
-    HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::set(const KeyType& key, MappedPassInType mapped)
-    {
-        AddResult result = inlineAdd(key, mapped);
-        if (!result.isNewEntry) {
-            // The inlineAdd call above found an existing hash table entry; we need to set the mapped value.
-            MappedTraits::store(mapped, result.storedValue->value);
-        }
-        return result;
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::AddResult
-    HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::set(RawKeyType key, MappedPassInType mapped)
-    {
-        AddResult result = inlineAdd(key, mapped);
-        if (!result.isNewEntry) {
-            // The inlineAdd call above found an existing hash table entry; we need to set the mapped value.
-            MappedTraits::store(mapped, result.storedValue->value);
-        }
-        return result;
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::AddResult
-    HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::add(const KeyType& key, MappedPassInType mapped)
-    {
-        return inlineAdd(key, mapped);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    typename HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::AddResult
-    HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::add(RawKeyType key, MappedPassInType mapped)
-    {
-        return inlineAdd(key, mapped);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename MappedTraits>
-    typename HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::MappedPeekType
-    HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::get(const KeyType& key) const
-    {
-        ValueType* entry = const_cast<HashTableType&>(m_impl).lookup(key);
-        if (!entry)
-            return MappedTraits::peek(MappedTraits::emptyValue());
-        return MappedTraits::peek(entry->value);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename MappedTraits>
-    typename HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::MappedPeekType
-    inline HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::inlineGet(RawKeyType key) const
-    {
-        ValueType* entry = const_cast<HashTableType&>(m_impl).template lookup<Translator>(key);
-        if (!entry)
-            return MappedTraits::peek(MappedTraits::emptyValue());
-        return MappedTraits::peek(entry->value);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename MappedTraits>
-    typename HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::MappedPeekType
-    HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::get(RawKeyType key) const
-    {
-        return inlineGet(key);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline void HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::remove(iterator it)
-    {
-        if (it.m_impl == m_impl.end())
-            return;
-        m_impl.remove(it.m_impl);
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline void HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::remove(const KeyType& key)
-    {
-        remove(find(key));
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline void HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::remove(RawKeyType key)
-    {
-        remove(find(key));
-    }
-
-    template<typename T, typename U, typename V, typename W, typename X>
-    inline void HashMap<RefPtr<T>, U, V, W, X, DefaultAllocator>::clear()
-    {
-        m_impl.clear();
-    }
-
-    template<typename T, typename U, typename V, typename W, typename MappedTraits>
-    typename HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::MappedPassOutType
-    HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::take(const KeyType& key)
-    {
-        iterator it = find(key);
-        if (it == end())
-            return MappedTraits::passOut(MappedTraits::emptyValue());
-        MappedPassOutType result = MappedTraits::passOut(it->value);
-        remove(it);
-        return result;
-    }
-
-    template<typename T, typename U, typename V, typename W, typename MappedTraits>
-    typename HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::MappedPassOutType
-    HashMap<RefPtr<T>, U, V, W, MappedTraits, DefaultAllocator>::take(RawKeyType key)
-    {
-        iterator it = find(key);
-        if (it == end())
-            return MappedTraits::passOut(MappedTraits::emptyValue());
-        MappedPassOutType result = MappedTraits::passOut(it->value);
-        remove(it);
-        return result;
-    }
-
-} // namespace WTF
-
-#endif // RefPtrHashMap_h

third_party/WebKit/Source/wtf/wtf.gypi

@@ -99,7 +99,6 @@
             'RefCountedLeakCounter.cpp',
             'RefCountedLeakCounter.h',
             'RefPtr.h',
-            'RefPtrHashMap.h',
             'RetainPtr.h',
             'SHA1.cpp',
             'SHA1.h',