Merge WebKit at r80534: Intial merge by Git

Change-Id: Ia7a83357124c9e1cdb1debf55d9661ec0bd09a61

1 files changed, 189 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/collector/handles/Handle.h b/Source/JavaScriptCore/collector/handles/Handle.h
new file mode 100644
index 0000000..98c60ec
--- /dev/null
+++ b/Source/JavaScriptCore/collector/handles/Handle.h
@@ -0,0 +1,189 @@
+/*
+ * 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>;
+
+class HandleBase {
+    friend class HandleHeap;
+
+public:
+    bool operator!() const { return isEmpty(); }
+
+    // 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; }
+
+    bool isEmpty() const { return !m_slot || !*m_slot; }
+
+protected:
+    HandleBase(HandleSlot slot)
+        : m_slot(slot)
+    {
+        ASSERT(slot);
+    }
+
+    enum DontNullCheckSlotTag { DontNullCheckSlot };
+    HandleBase(HandleSlot slot, DontNullCheckSlotTag)
+        : m_slot(slot)
+    {
+    }
+    
+    HandleSlot slot() const { return m_slot; }
+    void invalidate()
+    {
+        // It is unsafe to use a handle after invalidating it.
+        m_slot = 0;
+    }
+
+    // needed by Global<>::operator= and Global<>::set if it's an empty handle
+    void setSlot(HandleSlot slot)
+    {
+        ASSERT(!m_slot);
+        ASSERT(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->() { return static_cast<Base*>(this)->get(); }
+    const T* operator->() const { return static_cast<const Base*>(this)->get(); }
+    T* operator*() { return static_cast<Base*>(this)->get(); }
+    const T* operator*() const { return static_cast<const Base*>(this)->get(); }
+};
+
+template <typename Base> struct HandleConverter<Base, Unknown> {
+};
+
+template <typename T> class Handle : public HandleBase, public HandleConverter<Handle<T>, T> {
+public:
+    typedef typename HandleTypes<T>::ExternalType ExternalType;
+    template <typename U> Handle(Handle<U> o)
+    {
+        typename HandleTypes<T>::template validateUpcast<U>();
+        m_slot = o.slot();
+    }
+
+    ExternalType get() const { return HandleTypes<T>::getFromSlot(this->slot()); }
+
+protected:
+
+    Handle(HandleSlot slot)
+        : HandleBase(slot)
+    {
+    }
+    Handle(HandleSlot slot, HandleBase::DontNullCheckSlotTag)
+        : HandleBase(slot, HandleBase::DontNullCheckSlot)
+    {
+    }
+    
+private:
+    friend class HandleHeap;
+
+    static Handle<T> wrapSlot(HandleSlot slot)
+    {
+        return Handle<T>(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