/*
 * Copyright (C) 2005, 2006, 2007, 2008 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

namespace WTF
{

// This specialization is a direct copy of HashMap, with overloaded functions
// to allow for lookup by pointer instead of RefPtr, avoiding ref-count churn.

// FIXME: Find a better way that doesn't require an entire copy of the HashMap template.

template<typename RawKeyType, typename ValueType, typename ValueTraits, typename HashFunctions>
struct RefPtrHashMapRawKeyTranslator {
    typedef typename ValueType::first_type KeyType;
    typedef typename ValueType::second_type MappedType;
    typedef typename ValueTraits::FirstTraits KeyTraits;
    typedef typename ValueTraits::SecondTraits MappedTraits;

    static unsigned hash(RawKeyType key)
    {
        return HashFunctions::hash(key);
    }
    static bool equal(const KeyType &a, RawKeyType b)
    {
        return HashFunctions::equal(a, b);
    }
    static void translate(ValueType &location, RawKeyType key, const MappedType &mapped)
    {
        location.first = key;
        location.second = mapped;
    }
};

template<typename T, typename MappedArg, typename HashArg, typename KeyTraitsArg, typename MappedTraitsArg>
class HashMap<RefPtr<T>, MappedArg, HashArg, KeyTraitsArg, MappedTraitsArg>
{
private:
    typedef KeyTraitsArg KeyTraits;
    typedef MappedTraitsArg MappedTraits;
    typedef PairHashTraits<KeyTraits, MappedTraits> ValueTraits;

public:
    typedef typename KeyTraits::TraitType KeyType;
    typedef T *RawKeyType;
    typedef typename MappedTraits::TraitType MappedType;
    typedef typename ValueTraits::TraitType ValueType;

private:
    typedef HashArg HashFunctions;

    typedef HashTable<KeyType, ValueType, PairFirstExtractor<ValueType>,
            HashFunctions, ValueTraits, KeyTraits> HashTableType;

    typedef RefPtrHashMapRawKeyTranslator<RawKeyType, ValueType, ValueTraits, HashFunctions>
    RawKeyTranslator;

public:
    typedef HashTableIteratorAdapter<HashTableType, ValueType> iterator;
    typedef HashTableConstIteratorAdapter<HashTableType, ValueType> const_iterator;

    void swap(HashMap &);

    int size() const;
    int 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;
    MappedType get(const KeyType &) const;
    MappedType get(RawKeyType) const;
    MappedType 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
    pair<iterator, bool> set(const KeyType &, const MappedType &);
    pair<iterator, bool> set(RawKeyType, const MappedType &);

    // 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
    pair<iterator, bool> add(const KeyType &, const MappedType &);
    pair<iterator, bool> add(RawKeyType, const MappedType &);

    void remove(const KeyType &);
    void remove(RawKeyType);
    void remove(iterator);
    void clear();

    MappedType take(const KeyType &); // efficient combination of get with remove
    MappedType take(RawKeyType); // efficient combination of get with remove

private:
    pair<iterator, bool> inlineAdd(const KeyType &, const MappedType &);
    pair<iterator, bool> inlineAdd(RawKeyType, const MappedType &);

    HashTableType m_impl;
};

template<typename T, typename U, typename V, typename W, typename X>
inline void HashMap<RefPtr<T>, U, V, W, X>::swap(HashMap &other)
{
    m_impl.swap(other.m_impl);
}

template<typename T, typename U, typename V, typename W, typename X>
inline int HashMap<RefPtr<T>, U, V, W, X>::size() const
{
    return m_impl.size();
}

template<typename T, typename U, typename V, typename W, typename X>
inline int HashMap<RefPtr<T>, U, V, W, X>::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>::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>::iterator HashMap<RefPtr<T>, U, V, W, X>::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>::iterator HashMap<RefPtr<T>, U, V, W, X>::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>::const_iterator HashMap<RefPtr<T>, U, V, W, X>::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>::const_iterator HashMap<RefPtr<T>, U, V, W, X>::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>::iterator HashMap<RefPtr<T>, U, V, W, X>::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>::iterator HashMap<RefPtr<T>, U, V, W, X>::find(RawKeyType key)
{
    return m_impl.template find<RawKeyType, RawKeyTranslator>(key);
}

template<typename T, typename U, typename V, typename W, typename X>
inline typename HashMap<RefPtr<T>, U, V, W, X>::const_iterator HashMap<RefPtr<T>, U, V, W, X>::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>::const_iterator HashMap<RefPtr<T>, U, V, W, X>::find(RawKeyType key) const
{
    return m_impl.template find<RawKeyType, RawKeyTranslator>(key);
}

template<typename T, typename U, typename V, typename W, typename X>
inline bool HashMap<RefPtr<T>, U, V, W, X>::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>::contains(RawKeyType key) const
{
    return m_impl.template contains<RawKeyType, RawKeyTranslator>(key);
}

template<typename T, typename U, typename V, typename W, typename X>
inline pair<typename HashMap<RefPtr<T>, U, V, W, X>::iterator, bool>
HashMap<RefPtr<T>, U, V, W, X>::inlineAdd(const KeyType &key, const MappedType &mapped)
{
    typedef HashMapTranslator<ValueType, ValueTraits, HashFunctions> TranslatorType;
    return m_impl.template add<KeyType, MappedType, TranslatorType>(key, mapped);
}

template<typename T, typename U, typename V, typename W, typename X>
inline pair<typename HashMap<RefPtr<T>, U, V, W, X>::iterator, bool>
HashMap<RefPtr<T>, U, V, W, X>::inlineAdd(RawKeyType key, const MappedType &mapped)
{
    return m_impl.template add<RawKeyType, MappedType, RawKeyTranslator>(key, mapped);
}

template<typename T, typename U, typename V, typename W, typename X>
pair<typename HashMap<RefPtr<T>, U, V, W, X>::iterator, bool>
HashMap<RefPtr<T>, U, V, W, X>::set(const KeyType &key, const MappedType &mapped)
{
    pair<iterator, bool> result = inlineAdd(key, mapped);
    if (!result.second) {
        // add call above didn't change anything, so set the mapped value
        result.first->second = mapped;
    }
    return result;
}

template<typename T, typename U, typename V, typename W, typename X>
pair<typename HashMap<RefPtr<T>, U, V, W, X>::iterator, bool>
HashMap<RefPtr<T>, U, V, W, X>::set(RawKeyType key, const MappedType &mapped)
{
    pair<iterator, bool> result = inlineAdd(key, mapped);
    if (!result.second) {
        // add call above didn't change anything, so set the mapped value
        result.first->second = mapped;
    }
    return result;
}

template<typename T, typename U, typename V, typename W, typename X>
pair<typename HashMap<RefPtr<T>, U, V, W, X>::iterator, bool>
HashMap<RefPtr<T>, U, V, W, X>::add(const KeyType &key, const MappedType &mapped)
{
    return inlineAdd(key, mapped);
}

template<typename T, typename U, typename V, typename W, typename X>
pair<typename HashMap<RefPtr<T>, U, V, W, X>::iterator, bool>
HashMap<RefPtr<T>, U, V, W, X>::add(RawKeyType key, const MappedType &mapped)
{
    return inlineAdd(key, mapped);
}

template<typename T, typename U, typename V, typename W, typename MappedTraits>
typename HashMap<RefPtr<T>, U, V, W, MappedTraits>::MappedType
HashMap<RefPtr<T>, U, V, W, MappedTraits>::get(const KeyType &key) const
{
    ValueType *entry = const_cast<HashTableType &>(m_impl).lookup(key);
    if (!entry) {
        return MappedTraits::emptyValue();
    }
    return entry->second;
}

template<typename T, typename U, typename V, typename W, typename MappedTraits>
typename HashMap<RefPtr<T>, U, V, W, MappedTraits>::MappedType
inline HashMap<RefPtr<T>, U, V, W, MappedTraits>::inlineGet(RawKeyType key) const
{
    ValueType *entry = const_cast<HashTableType &>(m_impl).template lookup<RawKeyType, RawKeyTranslator>(key);
    if (!entry) {
        return MappedTraits::emptyValue();
    }
    return entry->second;
}

template<typename T, typename U, typename V, typename W, typename MappedTraits>
typename HashMap<RefPtr<T>, U, V, W, MappedTraits>::MappedType
HashMap<RefPtr<T>, U, V, W, MappedTraits>::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>::remove(iterator it)
{
    if (it.m_impl == m_impl.end()) {
        return;
    }
    m_impl.checkTableConsistency();
    m_impl.removeWithoutEntryConsistencyCheck(it.m_impl);
}

template<typename T, typename U, typename V, typename W, typename X>
inline void HashMap<RefPtr<T>, U, V, W, X>::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>::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>::clear()
{
    m_impl.clear();
}

template<typename T, typename U, typename V, typename W, typename MappedTraits>
typename HashMap<RefPtr<T>, U, V, W, MappedTraits>::MappedType
HashMap<RefPtr<T>, U, V, W, MappedTraits>::take(const KeyType &key)
{
    // This can probably be made more efficient to avoid ref/deref churn.
    iterator it = find(key);
    if (it == end()) {
        return MappedTraits::emptyValue();
    }
    typename HashMap<RefPtr<T>, U, V, W, MappedTraits>::MappedType result = it->second;
    remove(it);
    return result;
}

template<typename T, typename U, typename V, typename W, typename MappedTraits>
typename HashMap<RefPtr<T>, U, V, W, MappedTraits>::MappedType
HashMap<RefPtr<T>, U, V, W, MappedTraits>::take(RawKeyType key)
{
    // This can probably be made more efficient to avoid ref/deref churn.
    iterator it = find(key);
    if (it == end()) {
        return MappedTraits::emptyValue();
    }
    typename HashMap<RefPtr<T>, U, V, W, MappedTraits>::MappedType result = it->second;
    remove(it);
    return result;
}

} // namespace WTF

#endif
