/*
 * 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