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Diffstat (limited to 'Source/JavaScriptCore/runtime/WeakGCMap.h')
| -rw-r--r-- | Source/JavaScriptCore/runtime/WeakGCMap.h | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/runtime/WeakGCMap.h b/Source/JavaScriptCore/runtime/WeakGCMap.h new file mode 100644 index 000000000..1bb3cd5bb --- /dev/null +++ b/Source/JavaScriptCore/runtime/WeakGCMap.h @@ -0,0 +1,191 @@ +/* + * Copyright (C) 2009 Apple Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF + * THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef WeakGCMap_h +#define WeakGCMap_h + +#include "Handle.h" +#include "JSGlobalData.h" +#include <wtf/HashMap.h> + +namespace JSC { + +// A HashMap for GC'd values that removes entries when the associated value +// dies. +template <typename KeyType, typename MappedType> struct DefaultWeakGCMapFinalizerCallback { + static void* finalizerContextFor(KeyType key) + { + return reinterpret_cast<void*>(key); + } + + static KeyType keyForFinalizer(void* context, typename HandleTypes<MappedType>::ExternalType) + { + return reinterpret_cast<KeyType>(context); + } +}; + +template<typename KeyType, typename MappedType, typename FinalizerCallback = DefaultWeakGCMapFinalizerCallback<KeyType, MappedType>, typename HashArg = typename DefaultHash<KeyType>::Hash, typename KeyTraitsArg = HashTraits<KeyType> > +class WeakGCMap : private WeakHandleOwner { + WTF_MAKE_FAST_ALLOCATED; + WTF_MAKE_NONCOPYABLE(WeakGCMap); + + typedef HashMap<KeyType, HandleSlot, HashArg, KeyTraitsArg> MapType; + typedef typename HandleTypes<MappedType>::ExternalType ExternalType; + typedef typename MapType::iterator map_iterator; + +public: + + struct iterator { + friend class WeakGCMap; + iterator(map_iterator iter) + : m_iterator(iter) + { + } + + std::pair<KeyType, ExternalType> get() const { return std::make_pair(m_iterator->first, HandleTypes<MappedType>::getFromSlot(m_iterator->second)); } + std::pair<KeyType, HandleSlot> getSlot() const { return *m_iterator; } + + iterator& operator++() { ++m_iterator; return *this; } + + // postfix ++ intentionally omitted + + // Comparison. + bool operator==(const iterator& other) const { return m_iterator == other.m_iterator; } + bool operator!=(const iterator& other) const { return m_iterator != other.m_iterator; } + + private: + map_iterator m_iterator; + }; + + WeakGCMap() + { + } + + bool isEmpty() { return m_map.isEmpty(); } + void clear() + { + map_iterator end = m_map.end(); + for (map_iterator ptr = m_map.begin(); ptr != end; ++ptr) + HandleHeap::heapFor(ptr->second)->deallocate(ptr->second); + m_map.clear(); + } + + bool contains(const KeyType& key) const + { + return m_map.contains(key); + } + + iterator find(const KeyType& key) + { + return m_map.find(key); + } + + void remove(iterator iter) + { + ASSERT(iter.m_iterator != m_map.end()); + HandleSlot slot = iter.m_iterator->second; + ASSERT(slot); + HandleHeap::heapFor(slot)->deallocate(slot); + m_map.remove(iter.m_iterator); + } + + ExternalType get(const KeyType& key) const + { + return HandleTypes<MappedType>::getFromSlot(m_map.get(key)); + } + + HandleSlot getSlot(const KeyType& key) const + { + return m_map.get(key); + } + + pair<iterator, bool> add(JSGlobalData& globalData, const KeyType& key, ExternalType value) + { + pair<typename MapType::iterator, bool> iter = m_map.add(key, 0); + if (iter.second) { + HandleSlot slot = globalData.heap.handleHeap()->allocate(); + iter.first->second = slot; + HandleHeap::heapFor(slot)->makeWeak(slot, this, FinalizerCallback::finalizerContextFor(key)); + HandleHeap::heapFor(slot)->writeBarrier(slot, value); + *slot = value; + } + return iter; + } + + void set(iterator iter, ExternalType value) + { + HandleSlot slot = iter.m_iterator->second; + ASSERT(slot); + HandleHeap::heapFor(slot)->writeBarrier(slot, value); + *slot = value; + } + + void set(JSGlobalData& globalData, const KeyType& key, ExternalType value) + { + pair<typename MapType::iterator, bool> iter = m_map.add(key, 0); + HandleSlot slot = iter.first->second; + if (iter.second) { + slot = globalData.heap.handleHeap()->allocate(); + HandleHeap::heapFor(slot)->makeWeak(slot, this, key); + iter.first->second = slot; + } + HandleHeap::heapFor(slot)->writeBarrier(slot, value); + *slot = value; + } + + ExternalType take(const KeyType& key) + { + HandleSlot slot = m_map.take(key); + if (!slot) + return HashTraits<ExternalType>::emptyValue(); + ExternalType result = HandleTypes<MappedType>::getFromSlot(slot); + HandleHeap::heapFor(slot)->deallocate(slot); + return result; + } + + size_t size() { return m_map.size(); } + + iterator begin() { return iterator(m_map.begin()); } + iterator end() { return iterator(m_map.end()); } + + ~WeakGCMap() + { + clear(); + } + +private: + virtual void finalize(Handle<Unknown> handle, void* context) + { + HandleSlot slot = m_map.take(FinalizerCallback::keyForFinalizer(context, HandleTypes<MappedType>::getFromSlot(handle.slot()))); + ASSERT(slot); + HandleHeap::heapFor(slot)->deallocate(slot); + } + + MapType m_map; +}; + +} // namespace JSC + +#endif // WeakGCMap_h |