Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 191 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/runtime/WeakGCMap.h b/Source/JavaScriptCore/runtime/WeakGCMap.h
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+++ b/Source/JavaScriptCore/runtime/WeakGCMap.h
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+/*
+ * 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