--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/platform/PurgeableBuffer.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2008, 2010 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. ``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
+ * 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 PurgeableBuffer_h
+#define PurgeableBuffer_h
+
+#include <wtf/Noncopyable.h>
+#include <wtf/PassOwnPtr.h>
+#include <wtf/Vector.h>
+
+namespace WebCore {
+    
+    class PurgeableBuffer : public Noncopyable {
+    public:
+        static PassOwnPtr<PurgeableBuffer> create(const char* data, size_t);
+        static PassOwnPtr<PurgeableBuffer> create(const Vector<char>& vector) { return create(vector.data(), vector.size()); }
+        
+        ~PurgeableBuffer();
+
+        // Call makePurgeable(false) and check the return value before accessing the data.
+        const char* data() const;
+        size_t size() const { return m_size; }
+        
+        enum PurgePriority { PurgeLast, PurgeMiddle, PurgeFirst, PurgeDefault = PurgeMiddle };
+        PurgePriority purgePriority() const { return m_purgePriority; }
+        void setPurgePriority(PurgePriority);
+        
+        bool isPurgeable() const { return m_state != NonVolatile; }
+        bool wasPurged() const;
+
+        bool makePurgeable(bool purgeable);
+        
+    private:
+        PurgeableBuffer(char* data, size_t);
+    
+        char* m_data;
+        size_t m_size;
+        PurgePriority m_purgePriority;
+
+        enum State { NonVolatile, Volatile, Purged };
+        mutable State m_state;
+    };
+
+#if !OS(DARWIN) || defined(BUILDING_ON_TIGER) || PLATFORM(QT) || PLATFORM(GTK)
+    inline PassOwnPtr<PurgeableBuffer> PurgeableBuffer::create(const char*, size_t) { return PassOwnPtr<PurgeableBuffer>(); }
+    inline PurgeableBuffer::~PurgeableBuffer() { }
+    inline const char* PurgeableBuffer::data() const { return 0; }
+    inline void PurgeableBuffer::setPurgePriority(PurgePriority) { }
+    inline bool PurgeableBuffer::wasPurged() const { return false; }
+    inline bool PurgeableBuffer::makePurgeable(bool) { return false; }
+#endif
+    
+}
+
+#endif