diff -r 000000000000 -r 4f2f89ce4247 WebKit2/Shared/qt/UpdateChunk.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebKit2/Shared/qt/UpdateChunk.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2010 Apple Inc. All rights reserved.
+ * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
+ *
+ * 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.
+ */
+
+#include "UpdateChunk.h"
+
+#include "ArgumentDecoder.h"
+#include "ArgumentEncoder.h"
+#include "Attachment.h"
+#include "WebCoreArgumentCoders.h"
+#include <QDebug>
+#include <QFile>
+#include <QImage>
+#include <QTemporaryFile>
+#include <WebCore/FloatRect.h>
+#include <WebCore/PlatformString.h>
+#include <wtf/Vector.h>
+
+using namespace WebCore;
+using namespace std;
+
+namespace WebKit {
+    
+struct MappedMemory {
+    QFile* file;
+    uchar* data;
+    size_t size;
+    void markUsed() { *reinterpret_cast<uint64_t*>(data) = 0; }
+    void markFree() { *reinterpret_cast<uint64_t*>(data) = 0xdeadbeef; }
+    bool isFree() { return *reinterpret_cast<uint64_t*>(data) == 0xdeadbeef; }
+};
+
+static Vector<MappedMemory>* mmapPool;
+    
+static MappedMemory* mapMemory(size_t size)
+{
+    if (!mmapPool)
+        mmapPool = new Vector<MappedMemory>;
+        
+    for (unsigned n = 0; n < mmapPool->size(); ++n) {
+        MappedMemory& current = mmapPool->at(n);
+        if (current.size >= size && current.isFree()) {
+            current.markUsed();
+            return &current;
+        }
+    }
+    MappedMemory newMap;
+    newMap.size = size;
+    // FIXME: Clean up or reuse leftover map files from the disk.
+    newMap.file = new QTemporaryFile("WebKit2UpdateChunk");
+    newMap.file->open(QIODevice::ReadWrite);
+    newMap.file->resize(newMap.size);
+    newMap.data = newMap.file->map(0, newMap.size);
+    newMap.file->close();
+    newMap.markUsed();
+    mmapPool->append(newMap);
+    return &mmapPool->last();
+}
+    
+static MappedMemory* mapFile(QString fileName, size_t size)
+{
+    if (!mmapPool)
+        mmapPool = new Vector<MappedMemory>;
+    for (unsigned n = 0; n < mmapPool->size(); ++n) {
+        MappedMemory& current = mmapPool->at(n);
+        if (current.file->fileName() == fileName) {
+            ASSERT(!current.isFree());
+            return &current;
+        }
+    }
+    MappedMemory newMap;
+    newMap.file = new QFile(fileName);
+    if (!newMap.file->open(QIODevice::ReadWrite))
+        return 0;
+    newMap.data = newMap.file->map(0, size);
+    ASSERT(!newMap.isFree());
+    newMap.file->close();
+    mmapPool->append(newMap);
+    return &mmapPool->last();
+}
+
+UpdateChunk::UpdateChunk()
+    : m_mappedMemory(0)
+{
+}
+
+UpdateChunk::UpdateChunk(const IntRect& rect)
+    : m_rect(rect)
+    , m_mappedMemory(mapMemory(size()))
+{
+}
+
+UpdateChunk::~UpdateChunk()
+{
+    if (m_mappedMemory)
+        m_mappedMemory->markFree();
+}
+
+uint8_t* UpdateChunk::data()
+{
+    ASSERT(m_mappedMemory);
+    ASSERT(m_mappedMemory->data);
+    return reinterpret_cast<uint8_t*>(m_mappedMemory->data);
+}
+
+void UpdateChunk::encode(CoreIPC::ArgumentEncoder& encoder) const
+{
+    encoder.encode(m_rect);
+    encoder.encode(String(m_mappedMemory->file->fileName()));
+
+    m_mappedMemory = 0;
+}
+
+bool UpdateChunk::decode(CoreIPC::ArgumentDecoder& decoder, UpdateChunk& chunk)
+{
+    IntRect rect;
+    if (!decoder.decode(rect))
+        return false;
+    chunk.m_rect = rect;
+    
+    String fileName;
+    if (!decoder.decode(fileName))
+        return false;
+
+    chunk.m_mappedMemory = mapFile(fileName, chunk.size());
+
+    return chunk.m_mappedMemory->data;
+}
+
+QImage UpdateChunk::createImage()
+{
+    return QImage(data(), m_rect.width(), m_rect.height(), QImage::Format_RGB32);
+}
+
+} // namespace WebKit