WebCore/loader/CachedImage.cpp

/*
    This file is part of the KDE libraries

    Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
    Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
    Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
    Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
    Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.

    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., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.

    This class provides all functionality needed for loading images, style sheets and html
    pages from the web. It has a memory cache for these objects.
*/

#include "config.h"
#include "CachedImage.h"

#include "Cache.h"
#include "CachedResourceClient.h"
#include "CachedResourceClientWalker.h"
#include "DocLoader.h"
#include "Image.h"
#include "LoaderFunctions.h"
#include "Request.h"
#include <wtf/Vector.h>

using std::max;

namespace WebCore {

CachedImage::CachedImage(DocLoader* dl, const String &url, CachePolicy cachePolicy, time_t _expireDate)
    : CachedResource(url, ImageResource, cachePolicy, _expireDate)
    , m_dataSize(0)
{
    m_image = 0;
    m_errorOccurred = false;
    m_status = Unknown;
    m_loading = true;
}

CachedImage::~CachedImage()
{
    clear();
}

void CachedImage::ref(CachedResourceClient* c)
{
    CachedResource::ref(c);

    if (!imageRect().isEmpty())
        c->imageChanged(this);

    if (!m_loading)
        c->notifyFinished(this);
}

void CachedImage::deref(CachedResourceClient *c)
{
    Cache::flush();
    CachedResource::deref(c);
    if (canDelete() && m_free)
        delete this;
}

Image* CachedImage::image() const
{
    if (m_errorOccurred)
        return Cache::brokenImage;

    if (m_image)
        return m_image;

    return Cache::nullImage;
}

IntSize CachedImage::imageSize() const
{
    return (m_image ? m_image->size() : IntSize());
}

IntRect CachedImage::imageRect() const
{
    return (m_image ? m_image->rect() : IntRect());
}

void CachedImage::notifyObservers()
{
    CachedResourceClientWalker w(m_clients);
    while (CachedResourceClient *c = w.next())
        c->imageChanged(this);
}

void CachedImage::clear()
{
    delete m_image;
    m_image = 0;
    setSize(0);
}

inline void CachedImage::createImage()
{
    // Create the image if it doesn't yet exist.
    if (!m_image)
        m_image = new Image(this, ResponseMIMEType(m_response) == "application/pdf");
}

Vector<char>& CachedImage::bufferData(const char* bytes, int addedSize, Request* request)
{
    createImage();

    // Add new bytes DIRECTLY to the buffer in the Image object.
    Vector<char>& buffer = m_image->dataBuffer();

    unsigned oldSize = buffer.size();
    buffer.resize(oldSize + addedSize);
    memcpy(buffer.data() + oldSize, bytes, addedSize);

    return buffer;
}

void CachedImage::data(Vector<char>& data, bool allDataReceived)
{
    createImage();

    bool sizeAvailable = false;

    m_dataSize = data.size();

    // Have the image update its data from its internal buffer.
    // It will not do anything now, but will delay decoding until 
    // queried for info (like size or specific image frames).
    sizeAvailable = m_image->setData(allDataReceived);

    // Go ahead and tell our observers to try to draw if we have either
    // received all the data or the size is known.  Each chunk from the
    // network causes observers to repaint, which will force that chunk
    // to decode.
    if (sizeAvailable || allDataReceived) {
        if (m_image->isNull()) {
            m_errorOccurred = true;
            notifyObservers();
            Cache::remove(this);
        } else
            notifyObservers();

        // FIXME: An animated GIF with a huge frame count can't have its size properly estimated.  The reason is that we don't
        // want to decode the image to determine the frame count, so what we do instead is max the projected size of a single
        // RGBA32 buffer (width*height*4) with the data size.  This will help ensure that large animated GIFs with thousands of
        // frames are properly designated as uncacheable.
        IntSize s = imageSize();
        setSize(max(s.width() * s.height() * 4, m_dataSize));
    }
    
    if (allDataReceived) {
        m_loading = false;
        checkNotify();
    }
}

void CachedImage::error()
{
    clear();
    m_errorOccurred = true;
    notifyObservers();
    m_loading = false;
    checkNotify();
}

void CachedImage::checkNotify()
{
    if (m_loading)
        return;

    CachedResourceClientWalker w(m_clients);
    while (CachedResourceClient* c = w.next())
        c->notifyFinished(this);
}

bool CachedImage::shouldStopAnimation(const Image* image)
{
    if (image != m_image)
        return false;
    
    CachedResourceClientWalker w(m_clients);
    while (CachedResourceClient* c = w.next()) {
        if (c->willRenderImage(this))
            return false;
    }

    return true;
}

void CachedImage::animationAdvanced(const Image* image)
{
    if (image == m_image)
        notifyObservers();
}

} //namespace WebCore