1 files changed, 219 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/heap/Handle.h b/Source/JavaScriptCore/heap/Handle.h
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+++ b/Source/JavaScriptCore/heap/Handle.h
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2011 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 Handle_h
+#define Handle_h
+
+#include "WriteBarrier.h"
+#include <wtf/Assertions.h>
+
+namespace JSC {
+
+/*
+    A Handle is a smart pointer that updates automatically when the garbage
+    collector moves the object to which it points.
+
+    The base Handle class represents a temporary reference to a pointer whose
+    lifetime is guaranteed by something else.
+*/
+
+template <class T> class Handle;
+
+// Creating a JSValue Handle is invalid
+template <> class Handle<JSValue>;
+
+// Forward declare WeakGCMap
+template<typename KeyType, typename MappedType, typename FinalizerCallback, typename HashArg, typename KeyTraitsArg> class WeakGCMap;
+
+class HandleBase {
+    friend class HandleHeap;
+    friend struct JSCallbackObjectData;
+    template <typename KeyType, typename MappedType, typename FinalizerCallback, typename HashArg, typename KeyTraitsArg> friend class WeakGCMap;
+
+public:
+    bool operator!() const { return !m_slot || !*m_slot; }
+
+    // This conversion operator allows implicit conversion to bool but not to other integer types.
+    typedef JSValue (HandleBase::*UnspecifiedBoolType);
+    operator UnspecifiedBoolType*() const { return (m_slot && *m_slot) ? reinterpret_cast<UnspecifiedBoolType*>(1) : 0; }
+
+protected:
+    HandleBase(HandleSlot slot)
+        : m_slot(slot)
+    {
+    }
+    
+    void swap(HandleBase& other) { std::swap(m_slot, other.m_slot); }
+
+    HandleSlot slot() const { return m_slot; }
+    void setSlot(HandleSlot slot)
+    {
+        m_slot = slot;
+    }
+
+private:
+    HandleSlot m_slot;
+};
+
+template <typename T> struct HandleTypes {
+    typedef T* ExternalType;
+    static ExternalType getFromSlot(HandleSlot slot) { return (slot && *slot) ? reinterpret_cast<ExternalType>(slot->asCell()) : 0; }
+    static JSValue toJSValue(T* cell) { return reinterpret_cast<JSCell*>(cell); }
+    template <typename U> static void validateUpcast() { T* temp; temp = (U*)0; }
+};
+
+template <> struct HandleTypes<Unknown> {
+    typedef JSValue ExternalType;
+    static ExternalType getFromSlot(HandleSlot slot) { return slot ? *slot : JSValue(); }
+    static JSValue toJSValue(const JSValue& v) { return v; }
+    template <typename U> static void validateUpcast() {}
+};
+
+template <typename Base, typename T> struct HandleConverter {
+    T* operator->()
+    {
+#if ENABLE(JSC_ZOMBIES)
+        ASSERT(!static_cast<const Base*>(this)->get() || !static_cast<const Base*>(this)->get()->isZombie());
+#endif
+        return static_cast<Base*>(this)->get();
+    }
+    const T* operator->() const
+    {
+#if ENABLE(JSC_ZOMBIES)
+        ASSERT(!static_cast<const Base*>(this)->get() || !static_cast<const Base*>(this)->get()->isZombie());
+#endif
+        return static_cast<const Base*>(this)->get();
+    }
+
+    T* operator*()
+    {
+#if ENABLE(JSC_ZOMBIES)
+        ASSERT(!static_cast<const Base*>(this)->get() || !static_cast<const Base*>(this)->get()->isZombie());
+#endif
+        return static_cast<Base*>(this)->get();
+    }
+    const T* operator*() const
+    {
+#if ENABLE(JSC_ZOMBIES)
+        ASSERT(!static_cast<const Base*>(this)->get() || !static_cast<const Base*>(this)->get()->isZombie());
+#endif
+        return static_cast<const Base*>(this)->get();
+    }
+};
+
+template <typename Base> struct HandleConverter<Base, Unknown> {
+    Handle<JSObject> asObject() const;
+    bool isObject() const { return jsValue().isObject(); }
+    bool getNumber(double number) const { return jsValue().getNumber(number); }
+    UString getString(ExecState*) const;
+    bool isUndefinedOrNull() const { return jsValue().isUndefinedOrNull(); }
+
+private:
+    JSValue jsValue() const
+    {
+#if ENABLE(JSC_ZOMBIES)
+        ASSERT(!static_cast<const Base*>(this)->get() || !static_cast<const Base*>(this)->get().isZombie());
+#endif
+        return static_cast<const Base*>(this)->get();
+    }
+};
+
+template <typename T> class Handle : public HandleBase, public HandleConverter<Handle<T>, T> {
+public:
+    template <typename A, typename B> friend class HandleConverter;
+    typedef typename HandleTypes<T>::ExternalType ExternalType;
+    template <typename U> Handle(Handle<U> o)
+    {
+        typename HandleTypes<T>::template validateUpcast<U>();
+        setSlot(o.slot());
+    }
+
+    void swap(Handle& other) { HandleBase::swap(other); }
+
+    ExternalType get() const { return HandleTypes<T>::getFromSlot(this->slot()); }
+
+protected:
+    Handle(HandleSlot slot = 0)
+        : HandleBase(slot)
+    {
+    }
+    
+private:
+    friend class HandleHeap;
+
+    static Handle<T> wrapSlot(HandleSlot slot)
+    {
+        return Handle<T>(slot);
+    }
+};
+
+template <typename Base> Handle<JSObject> HandleConverter<Base, Unknown>::asObject() const
+{
+    return Handle<JSObject>::wrapSlot(static_cast<const Base*>(this)->slot());
+}
+
+template <typename T, typename U> inline bool operator==(const Handle<T>& a, const Handle<U>& b)
+{ 
+    return a.get() == b.get(); 
+}
+
+template <typename T, typename U> inline bool operator==(const Handle<T>& a, U* b)
+{ 
+    return a.get() == b; 
+}
+
+template <typename T, typename U> inline bool operator==(T* a, const Handle<U>& b) 
+{
+    return a == b.get(); 
+}
+
+template <typename T, typename U> inline bool operator!=(const Handle<T>& a, const Handle<U>& b)
+{ 
+    return a.get() != b.get(); 
+}
+
+template <typename T, typename U> inline bool operator!=(const Handle<T>& a, U* b)
+{
+    return a.get() != b; 
+}
+
+template <typename T, typename U> inline bool operator!=(T* a, const Handle<U>& b)
+{ 
+    return a != b.get(); 
+}
+
+template <typename T, typename U> inline bool operator!=(const Handle<T>& a, JSValue b)
+{
+    return a.get() != b; 
+}
+
+template <typename T, typename U> inline bool operator!=(JSValue a, const Handle<U>& b)
+{ 
+    return a != b.get(); 
+}
+
+}
+
+#endif