From 81bc750723a18f21cd17d1b173cd2a4dda9cea6e Mon Sep 17 00:00:00 2001
From: Ben Murdoch <benm@google.com>
Date: Tue, 24 May 2011 11:24:40 +0100
Subject: Merge WebKit at r80534: Intial merge by Git

Change-Id: Ia7a83357124c9e1cdb1debf55d9661ec0bd09a61
---
 Source/JavaScriptCore/collector/handles/Global.h | 159 +++++++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 Source/JavaScriptCore/collector/handles/Global.h

(limited to 'Source/JavaScriptCore/collector/handles/Global.h')

diff --git a/Source/JavaScriptCore/collector/handles/Global.h b/Source/JavaScriptCore/collector/handles/Global.h
new file mode 100644
index 0000000..571fe31
--- /dev/null
+++ b/Source/JavaScriptCore/collector/handles/Global.h
@@ -0,0 +1,159 @@
+/*
+ * 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 Global_h
+#define Global_h
+
+#include "Assertions.h"
+#include "Handle.h"
+#include "HandleHeap.h"
+#include "JSGlobalData.h"
+
+namespace JSC {
+
+/*
+    A Global is a persistent handle whose lifetime is not limited to any given
+    scope. Use Globals for data members and global variables.
+*/
+
+template <typename T> class Global : public Handle<T> {
+public:
+    typedef typename Handle<T>::ExternalType ExternalType;
+    Global(JSGlobalData& globalData, ExternalType ptr = ExternalType())
+        : Handle<T>(globalData.allocateGlobalHandle())
+    {
+        internalSet(ptr);
+    }
+
+    Global(JSGlobalData& globalData, Handle<T> handle)
+        : Handle<T>(globalData.allocateGlobalHandle())
+    {
+        internalSet(handle.get());
+    }
+    
+    enum EmptyValueTag { EmptyValue };
+    Global(EmptyValueTag)
+        : Handle<T>(0, HandleBase::DontNullCheckSlot)
+    {
+    }
+
+    ~Global()
+    {
+        HandleSlot slot = this->slot();
+        if (slot)
+            HandleHeap::heapFor(slot)->deallocate(slot);
+    }
+
+    void set(JSGlobalData& globalData, ExternalType value)
+    {
+        if (!value) {
+            clear();
+            return;
+        }
+        if (!this->slot())
+            this->setSlot(globalData.allocateGlobalHandle());
+        internalSet(value);
+    }
+
+    template <typename U> Global& operator=(const Global<U>& handle)
+    {
+        if (handle.slot()) {
+            if (!this->slot())
+                this->setSlot(HandleHeap::heapFor(handle.slot())->allocate());
+            internalSet(handle.get());
+        } else
+            clear();
+        
+        return *this;
+    }
+    
+    Global& operator=(const Global& handle)
+    {
+        if (handle.slot()) {
+            if (!this->slot())
+                this->setSlot(HandleHeap::heapFor(handle.slot())->allocate());
+            internalSet(handle.get());
+        } else
+            clear();
+        
+        return *this;
+    }
+
+    void clear()
+    {
+        if (this->slot())
+            internalSet(ExternalType());
+    }
+
+    enum HashTableDeletedValueType { HashTableDeletedValue };
+    const static intptr_t HashTableDeletedValueTag = 0x1;
+    Global(HashTableDeletedValueType)
+        : Handle<T>(reinterpret_cast<HandleSlot>(HashTableDeletedValueTag))
+    {
+    }
+    bool isHashTableDeletedValue() const { return slot() == reinterpret_cast<HandleSlot>(HashTableDeletedValueTag); }
+
+    template <typename U> Global(const Global<U>& other)
+        : Handle<T>(other.slot() ? HandleHeap::heapFor(other.slot())->allocate() : 0, Handle<T>::DontNullCheckSlot)
+    {
+        if (other.slot())
+            internalSet(other.get());
+    }
+    
+    Global(const Global& other)
+        : Handle<T>(other.slot() ? HandleHeap::heapFor(other.slot())->allocate() : 0, Handle<T>::DontNullCheckSlot)
+    {
+        if (other.slot())
+            internalSet(other.get());
+    }
+
+protected:
+    void internalSet(ExternalType value)
+    {
+        JSValue newValue(HandleTypes<T>::toJSValue(value));
+        HandleSlot slot = this->slot();
+        ASSERT(slot);
+        HandleHeap::heapFor(slot)->writeBarrier(slot, newValue);
+        *slot = newValue;
+    }
+
+    using Handle<T>::slot;
+    
+};
+
+}
+
+namespace WTF {
+
+template<typename P> struct HashTraits<JSC::Global<P> > : GenericHashTraits<JSC::Global<P> > {
+    static const bool emptyValueIsZero = true;
+    static JSC::Global<P> emptyValue() { return JSC::Global<P>(JSC::Global<P>::EmptyValue); }
+    static void constructDeletedValue(JSC::Global<P>& slot) { new (&slot) JSC::Global<P>(JSC::Global<P>::HashTableDeletedValue); }
+    static bool isDeletedValue(const JSC::Global<P>& value) { return value.isHashTableDeletedValue(); }
+};
+
+}
+
+#endif // Global_h
-- 
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