1/*
2 * Copyright (C) 2006 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "ScalableImageDecoder.h"
29#include <wtf/Lock.h>
30
31class GIFImageReader;
32
33namespace WebCore {
34
35// This class decodes the GIF image format.
36class GIFImageDecoder final : public ScalableImageDecoder {
37public:
38 static Ref<ScalableImageDecoder> create(AlphaOption alphaOption, GammaAndColorProfileOption gammaAndColorProfileOption)
39 {
40 return adoptRef(*new GIFImageDecoder(alphaOption, gammaAndColorProfileOption));
41 }
42
43 virtual ~GIFImageDecoder();
44
45 enum GIFQuery { GIFFullQuery, GIFSizeQuery, GIFFrameCountQuery };
46
47 // ScalableImageDecoder
48 String filenameExtension() const final { return "gif"_s; }
49 void setData(SharedBuffer& data, bool allDataReceived) final;
50 bool setSize(const IntSize&) final;
51 size_t frameCount() const final;
52 RepetitionCount repetitionCount() const final;
53 ScalableImageDecoderFrame* frameBufferAtIndex(size_t index) final;
54 // CAUTION: setFailed() deletes |m_reader|. Be careful to avoid
55 // accessing deleted memory, especially when calling this from inside
56 // GIFImageReader!
57 bool setFailed() final;
58 void clearFrameBufferCache(size_t clearBeforeFrame) final;
59
60 // Callbacks from the GIF reader.
61 bool haveDecodedRow(unsigned frameIndex, const Vector<unsigned char>& rowBuffer, size_t width, size_t rowNumber, unsigned repeatCount, bool writeTransparentPixels);
62 bool frameComplete(unsigned frameIndex, unsigned frameDuration, ScalableImageDecoderFrame::DisposalMethod);
63 void gifComplete();
64
65private:
66 GIFImageDecoder(AlphaOption, GammaAndColorProfileOption);
67 void tryDecodeSize(bool allDataReceived) final { decode(0, GIFSizeQuery, allDataReceived); }
68 size_t findFirstRequiredFrameToDecode(size_t);
69
70 // If the query is GIFFullQuery, decodes the image up to (but not
71 // including) |haltAtFrame|. Otherwise, decodes as much as is needed to
72 // answer the query, ignoring bitmap data. If decoding fails but there
73 // is no more data coming, sets the "decode failure" flag.
74 void decode(unsigned haltAtFrame, GIFQuery, bool allDataReceived);
75
76 // Called to initialize the frame buffer with the given index, based on
77 // the previous frame's disposal method. Returns true on success. On
78 // failure, this will mark the image as failed.
79 bool initFrameBuffer(unsigned frameIndex);
80
81 bool m_currentBufferSawAlpha;
82 mutable RepetitionCount m_repetitionCount { RepetitionCountOnce };
83 std::unique_ptr<GIFImageReader> m_reader;
84};
85
86} // namespace WebCore
87