auto import from //depot/cupcake/@135843

1 files changed, 107 insertions, 0 deletions

diff --git a/JavaScriptCore/wtf/RefCounted.h b/JavaScriptCore/wtf/RefCounted.h
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+++ b/JavaScriptCore/wtf/RefCounted.h
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+/*
+ * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public License
+ * along with this library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef RefCounted_h
+#define RefCounted_h
+
+#include <wtf/Assertions.h>
+#include <wtf/Noncopyable.h>
+
+namespace WTF {
+
+// This base class holds the non-template methods and attributes.
+// The RefCounted class inherits from it reducing the template bloat
+// generated by the compiler (technique called template hoisting).
+class RefCountedBase : Noncopyable {
+public:
+    void ref()
+    {
+        ASSERT(!m_deletionHasBegun);
+        ++m_refCount;
+    }
+
+    bool hasOneRef() const
+    {
+        ASSERT(!m_deletionHasBegun);
+        return m_refCount == 1;
+    }
+
+    int refCount() const
+    {
+        return m_refCount;
+    }
+
+protected:
+    RefCountedBase(int initialRefCount)
+        : m_refCount(initialRefCount)
+#ifndef NDEBUG
+        , m_deletionHasBegun(false)
+#endif
+    {
+    }
+
+    ~RefCountedBase() {}
+
+    // Returns whether the pointer should be freed or not.
+    bool derefBase()
+    {
+        ASSERT(!m_deletionHasBegun);
+        ASSERT(m_refCount > 0);
+        if (m_refCount == 1) {
+#ifndef NDEBUG
+            m_deletionHasBegun = true;
+#endif
+            return true;
+        }
+
+        --m_refCount;
+        return false;
+    }
+
+private:
+    int m_refCount;
+#ifndef NDEBUG
+    bool m_deletionHasBegun;
+#endif
+};
+
+
+template<class T> class RefCounted : public RefCountedBase {
+public:
+    RefCounted(int initialRefCount = 1)
+        : RefCountedBase(initialRefCount)
+    {
+    }
+
+    void deref()
+    {
+        if (derefBase())
+            delete static_cast<T*>(this);
+    }
+
+protected:
+    ~RefCounted() {}
+};
+
+} // namespace WTF
+
+using WTF::RefCounted;
+
+#endif // RefCounted_h