Moving GraphicsContext and dependencies from core to platform.

Source/platform/image-decoders/gif/GIFImageDecoder.h

+/*
+ * Copyright (C) 2006 Apple Computer, 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:
+ * 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 COMPUTER, INC. ``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 COMPUTER, INC. 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 GIFImageDecoder_h
+#define GIFImageDecoder_h
+
+#include "platform/image-decoders/ImageDecoder.h"
+#include "wtf/Noncopyable.h"
+#include "wtf/OwnPtr.h"
+
+class GIFImageReader;
+
+typedef Vector<unsigned char> GIFRow;
+
+namespace WebCore {
+
+// This class decodes the GIF image format.
+class PLATFORM_EXPORT GIFImageDecoder : public ImageDecoder {
+    WTF_MAKE_NONCOPYABLE(GIFImageDecoder);
+public:
+    GIFImageDecoder(ImageSource::AlphaOption, ImageSource::GammaAndColorProfileOption, size_t maxDecodedBytes);
+    virtual ~GIFImageDecoder();
+
+    enum GIFParseQuery { GIFSizeQuery, GIFFrameCountQuery };
+
+    // ImageDecoder
+    virtual String filenameExtension() const OVERRIDE { return "gif"; }
+    virtual void setData(SharedBuffer* data, bool allDataReceived) OVERRIDE;
+    virtual bool isSizeAvailable() OVERRIDE;
+    virtual size_t frameCount() OVERRIDE;
+    virtual int repetitionCount() const OVERRIDE;
+    virtual ImageFrame* frameBufferAtIndex(size_t) OVERRIDE;
+    virtual bool frameIsCompleteAtIndex(size_t) const OVERRIDE;
+    virtual float frameDurationAtIndex(size_t) const OVERRIDE;
+    virtual size_t clearCacheExceptFrame(size_t) OVERRIDE;
+    // CAUTION: setFailed() deletes |m_reader|.  Be careful to avoid
+    // accessing deleted memory, especially when calling this from inside
+    // GIFImageReader!
+    virtual bool setFailed() OVERRIDE;
+
+    // Callbacks from the GIF reader.
+    bool haveDecodedRow(size_t frameIndex, GIFRow::const_iterator rowBegin, size_t width, size_t rowNumber, unsigned repeatCount, bool writeTransparentPixels);
+    bool frameComplete(size_t frameIndex);
+
+    // For testing.
+    bool parseCompleted() const;
+
+private:
+    virtual void clearFrameBuffer(size_t frameIndex) OVERRIDE;
+
+    // Parses as much as is needed to answer the query, ignoring bitmap
+    // data. If parsing fails, sets the "decode failure" flag.
+    void parse(GIFParseQuery);
+
+    // Decodes bitmap data of the frame. Depending on the disposal method
+    // of prior frames, also decodes all required prior frames. If decoding
+    // fails, sets the "decode failure" flag.
+    void decode(size_t frameIndex);
+
+    // Called to initialize the frame buffer with the given index, based on
+    // the previous frame's disposal method. Returns true on success. On
+    // failure, this will mark the image as failed.
+    bool initFrameBuffer(size_t frameIndex);
+
+    bool m_currentBufferSawAlpha;
+    mutable int m_repetitionCount;
+    OwnPtr<GIFImageReader> m_reader;
+};
+
+} // namespace WebCore
+
+#endif