diff -r 000000000000 -r 4f2f89ce4247 WebCore/loader/CachedMetadata.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/loader/CachedMetadata.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 2010 Google 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:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * 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.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
+ * OWNER 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 CachedMetadata_h
+#define CachedMetadata_h
+
+#include <wtf/RefCounted.h>
+#include <wtf/Vector.h>
+
+namespace WebCore {
+
+// Metadata retrieved from the embedding application's cache.
+//
+// Serialized data is NOT portable across architectures. However, reading the
+// data type ID will reject data generated with a different byte-order.
+class CachedMetadata : public RefCounted<CachedMetadata> {
+public:
+    static PassRefPtr<CachedMetadata> create(unsigned dataTypeID, const char* data, size_t size)
+    {
+        return adoptRef(new CachedMetadata(dataTypeID, data, size));
+    }
+
+    static PassRefPtr<CachedMetadata> deserialize(const char* data, size_t size)
+    {
+        return adoptRef(new CachedMetadata(data, size));
+    }
+
+    const Vector<char>& serialize() const
+    {
+        return m_serializedData;
+    }
+
+    ~CachedMetadata() { }
+
+    unsigned dataTypeID() const
+    {
+        return readUnsigned(dataTypeIDStart);
+    }
+
+    const char* data() const
+    {
+        if (m_serializedData.size() < dataStart)
+            return 0;
+        return m_serializedData.data() + dataStart;
+    }
+
+    size_t size() const
+    {
+        if (m_serializedData.size() < dataStart)
+            return 0;
+        return m_serializedData.size() - dataStart;
+    }
+
+private:
+    // Reads an unsigned value at position. Returns 0 on error.
+    unsigned readUnsigned(size_t position) const
+    {
+        if (m_serializedData.size() < position + sizeof(unsigned))
+            return 0;
+        return *reinterpret_cast<unsigned*>(const_cast<char*>(m_serializedData.data() + position));
+    }
+
+    // Appends an unsigned value to the end of the serialized data.
+    void appendUnsigned(unsigned value)
+    {
+        m_serializedData.append(reinterpret_cast<const char*>(&value), sizeof(unsigned));
+    }
+
+    CachedMetadata(const char* data, size_t size)
+    {
+        // Serialized metadata should have non-empty data.
+        ASSERT(size > dataStart);
+
+        m_serializedData.append(data, size);
+    }
+
+    CachedMetadata(unsigned dataTypeID, const char* data, size_t size)
+    {
+        // Don't allow an ID of 0, it is used internally to indicate errors.
+        ASSERT(dataTypeID);
+        ASSERT(data);
+
+        appendUnsigned(dataTypeID);
+        m_serializedData.append(data, size);
+    }
+
+    // Serialization offsets. Format: [DATA_TYPE_ID][DATA].
+    static const size_t dataTypeIDStart = 0;
+    static const size_t dataStart = sizeof(unsigned);
+
+    // Since the serialization format supports random access, storing it in
+    // serialized form avoids need for a copy during serialization.
+    Vector<char> m_serializedData;
+};
+
+}
+
+#endif