Moving GraphicsContext and dependencies from core to platform.

Source/core/platform/image-decoders/ImageDecoder.cpp

-/*
- * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
- *
- *  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., 51 Franklin Street, Fifth Floor,
- *  Boston, MA 02110-1301, USA.
- *
- */
-
-#include "config.h"
-#include "core/platform/image-decoders/ImageDecoder.h"
-
-#include "core/platform/image-decoders/bmp/BMPImageDecoder.h"
-#include "core/platform/image-decoders/gif/GIFImageDecoder.h"
-#include "core/platform/image-decoders/ico/ICOImageDecoder.h"
-#include "core/platform/image-decoders/jpeg/JPEGImageDecoder.h"
-#include "core/platform/image-decoders/png/PNGImageDecoder.h"
-#include "core/platform/image-decoders/webp/WEBPImageDecoder.h"
-#include "wtf/PassOwnPtr.h"
-
-namespace WebCore {
-
-static unsigned copyFromSharedBuffer(char* buffer, unsigned bufferLength, const SharedBuffer& sharedBuffer, unsigned offset)
-{
-    unsigned bytesExtracted = 0;
-    const char* moreData;
-    while (unsigned moreDataLength = sharedBuffer.getSomeData(moreData, offset)) {
-        unsigned bytesToCopy = std::min(bufferLength - bytesExtracted, moreDataLength);
-        memcpy(buffer + bytesExtracted, moreData, bytesToCopy);
-        bytesExtracted += bytesToCopy;
-        if (bytesExtracted == bufferLength)
-            break;
-        offset += bytesToCopy;
-    }
-    return bytesExtracted;
-}
-
-inline bool matchesGIFSignature(char* contents)
-{
-    return !memcmp(contents, "GIF87a", 6) || !memcmp(contents, "GIF89a", 6);
-}
-
-inline bool matchesPNGSignature(char* contents)
-{
-    return !memcmp(contents, "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A", 8);
-}
-
-inline bool matchesJPEGSignature(char* contents)
-{
-    return !memcmp(contents, "\xFF\xD8\xFF", 3);
-}
-
-inline bool matchesWebPSignature(char* contents)
-{
-    return !memcmp(contents, "RIFF", 4) && !memcmp(contents + 8, "WEBPVP", 6);
-}
-
-inline bool matchesBMPSignature(char* contents)
-{
-    return !memcmp(contents, "BM", 2);
-}
-
-inline bool matchesICOSignature(char* contents)
-{
-    return !memcmp(contents, "\x00\x00\x01\x00", 4);
-}
-
-inline bool matchesCURSignature(char* contents)
-{
-    return !memcmp(contents, "\x00\x00\x02\x00", 4);
-}
-
-PassOwnPtr<ImageDecoder> ImageDecoder::create(const SharedBuffer& data, ImageSource::AlphaOption alphaOption, ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption)
-{
-    static const unsigned longestSignatureLength = sizeof("RIFF????WEBPVP") - 1;
-    ASSERT(longestSignatureLength == 14);
-
-    size_t maxDecodedBytes = blink::Platform::current()->maxDecodedImageBytes();
-
-    char contents[longestSignatureLength];
-    if (copyFromSharedBuffer(contents, longestSignatureLength, data, 0) < longestSignatureLength)
-        return nullptr;
-
-    if (matchesJPEGSignature(contents))
-        return adoptPtr(new JPEGImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
-
-    if (matchesPNGSignature(contents))
-        return adoptPtr(new PNGImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
-
-    if (matchesGIFSignature(contents))
-        return adoptPtr(new GIFImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
-
-    if (matchesICOSignature(contents) || matchesCURSignature(contents))
-        return adoptPtr(new ICOImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
-
-    if (matchesWebPSignature(contents))
-        return adoptPtr(new WEBPImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
-
-    if (matchesBMPSignature(contents))
-        return adoptPtr(new BMPImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes));
-
-    return nullptr;
-}
-
-bool ImageDecoder::frameHasAlphaAtIndex(size_t index) const
-{
-    return !frameIsCompleteAtIndex(index) || m_frameBufferCache[index].hasAlpha();
-}
-
-bool ImageDecoder::frameIsCompleteAtIndex(size_t index) const
-{
-    return (index < m_frameBufferCache.size()) &&
-        (m_frameBufferCache[index].status() == ImageFrame::FrameComplete);
-}
-
-unsigned ImageDecoder::frameBytesAtIndex(size_t index) const
-{
-    if (m_frameBufferCache.size() <= index || m_frameBufferCache[index].status() == ImageFrame::FrameEmpty)
-        return 0;
-    // FIXME: Use the dimension of the requested frame.
-    return m_size.area() * sizeof(ImageFrame::PixelData);
-}
-
-size_t ImageDecoder::clearCacheExceptFrame(size_t clearExceptFrame)
-{
-    // Don't clear if there are no frames or only one frame.
-    if (m_frameBufferCache.size() <= 1)
-        return 0;
-
-    size_t frameBytesCleared = 0;
-    for (size_t i = 0; i < m_frameBufferCache.size(); ++i) {
-        if (i != clearExceptFrame) {
-            frameBytesCleared += frameBytesAtIndex(i);
-            clearFrameBuffer(i);
-        }
-    }
-    return frameBytesCleared;
-}
-
-void ImageDecoder::clearFrameBuffer(size_t frameIndex)
-{
-    m_frameBufferCache[frameIndex].clearPixelData();
-}
-
-size_t ImageDecoder::findRequiredPreviousFrame(size_t frameIndex, bool frameRectIsOpaque)
-{
-    ASSERT(frameIndex <= m_frameBufferCache.size());
-    if (!frameIndex) {
-        // The first frame doesn't rely on any previous data.
-        return kNotFound;
-    }
-
-    const ImageFrame* currBuffer = &m_frameBufferCache[frameIndex];
-    if ((frameRectIsOpaque || currBuffer->alphaBlendSource() == ImageFrame::BlendAtopBgcolor)
-        && currBuffer->originalFrameRect().contains(IntRect(IntPoint(), size())))
-        return kNotFound;
-
-    // The starting state for this frame depends on the previous frame's
-    // disposal method.
-    size_t prevFrame = frameIndex - 1;
-    const ImageFrame* prevBuffer = &m_frameBufferCache[prevFrame];
-    ASSERT(prevBuffer->requiredPreviousFrameIndexValid());
-
-    switch (prevBuffer->disposalMethod()) {
-    case ImageFrame::DisposeNotSpecified:
-    case ImageFrame::DisposeKeep:
-        // prevFrame will be used as the starting state for this frame.
-        // FIXME: Be even smarter by checking the frame sizes and/or alpha-containing regions.
-        return prevFrame;
-    case ImageFrame::DisposeOverwritePrevious:
-        // Frames that use the DisposeOverwritePrevious method are effectively
-        // no-ops in terms of changing the starting state of a frame compared to
-        // the starting state of the previous frame, so skip over them and
-        // return the required previous frame of it.
-        return prevBuffer->requiredPreviousFrameIndex();
-    case ImageFrame::DisposeOverwriteBgcolor:
-        // If the previous frame fills the whole image, then the current frame
-        // can be decoded alone. Likewise, if the previous frame could be
-        // decoded without reference to any prior frame, the starting state for
-        // this frame is a blank frame, so it can again be decoded alone.
-        // Otherwise, the previous frame contributes to this frame.
-        return (prevBuffer->originalFrameRect().contains(IntRect(IntPoint(), size()))
-            || (prevBuffer->requiredPreviousFrameIndex() == kNotFound)) ? kNotFound : prevFrame;
-    default:
-        ASSERT_NOT_REACHED();
-        return kNotFound;
-    }
-}
-
-} // namespace WebCore