WIP: Implement APNG

third_party/WebKit/Source/platform/image-decoders/png/PNGImageReader.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.
+ */
+
+
+#include "platform/image-decoders/SegmentReader.h"
+#include "platform/image-decoders/png/PNGImageDecoder.h"
+#include "platform/PlatformExport.h"
+#include "png.h"
+#include "wtf/Allocator.h"
+#include "wtf/PtrUtil.h"
+
+#ifndef PNGImageReader_h
+#define PNGImageReader_h
+
+namespace blink {
+
+class FastSharedBufferReader;
+
+class PLATFORM_EXPORT PNGImageReader final {
+    USING_FAST_MALLOC(PNGImageReader);
+    WTF_MAKE_NONCOPYABLE(PNGImageReader);
+public:
+    PNGImageReader(PNGImageDecoder*, size_t initialOffset);
+    ~PNGImageReader();
+
+    struct FrameInfo {
+        size_t readOffset;
+        size_t byteLength;
+        size_t duration;
+        IntRect frameRect;
+        uint8_t disposalMethod;
+        uint8_t alphaBlend;
+    };
+
+    
+    // This method tries to parse the data stream in the SegmentReader, up to
+    // the point where the PNGParseQuery can be answered.
+    // @return true when the query is fulfilled.
+    //         false when:
+    //         A) not enough data provided
+    //         B) the data processing by libpng fails. In this case, it also
+    //            calls setFailed() on m_decoder.
+    bool parse(SegmentReader&, PNGImageDecoder::PNGParseQuery);
+
+    void decode(SegmentReader&, size_t);
+    const FrameInfo& frameInfo(size_t) const;
+
+    // This will return the number of frames that have been detected in the
+    // stream so far. If an incomplete stream is provided, this number is not
+    // final. However, all frame info for the frames up to this number is
+    // available so it can be used by the client if it wants to.
+    size_t frameCount() const;
+
+    // This is a callback for libpng, when it encounters an unknown chunk.
+    void parseAnimationChunk(const char* tag, const void* dataChunk, size_t length);
+
+    png_structp pngPtr() const { return m_png; }
+    png_infop infoPtr() const { return m_info; }
+
+    void setHasAlpha(bool hasAlpha) { m_hasAlpha = hasAlpha; }
+    bool hasAlpha() const { return m_hasAlpha; }
+
+    png_bytep interlaceBuffer() const { return m_interlaceBuffer.get(); }
+    void createInterlaceBuffer(int size) { m_interlaceBuffer = wrapArrayUnique(new png_byte[size]); }
+#if USE(QCMSLIB)
+    png_bytep rowBuffer() const { return m_rowBuffer.get(); }
+    void createRowBuffer(int size) { m_rowBuffer = wrapArrayUnique(new png_byte[size]); }
+#endif
+
+
+private:
+    png_structp m_png;
+    png_infop m_info;
+    PNGImageDecoder* m_decoder;
+    size_t m_initialOffset;

[scroggo_chromium, 2016/10/25 14:59:07]

I'm assuming this will be unchanged. Can you mark it const?

+    size_t m_readOffset;
+    size_t m_bytesInfo;

[scroggo_chromium, 2016/10/25 14:59:07]

Can you add a comment explaining what this means?

+    bool m_hasAlpha;
+    // This flag is set to true when an fcTL chunk is encountered before the
+    // IDAT chunk(s). In that case, the IDAT data is the first frame.

[scroggo_chromium, 2016/10/25 14:59:07]

Otherwise, the IDAT is ignored.

+    bool m_idatIsPartOfAnimation;
+    bool m_isAnimated;
+    bool m_parsedSignature;
+
+    std::unique_ptr<png_byte[]> m_interlaceBuffer;
+    
+    Vector<FrameInfo, 1> m_frameInfo;
+    FrameInfo m_newFrame;
+
+    size_t processData(SegmentReader&, size_t offset, size_t length);
+    bool parseSize(SegmentReader&);
+    void parseFrameInfo(const png_byte* data);
+    void endFrameDecoding();

[scroggo_chromium, 2016/10/25 14:59:07]

nit: I'd put this after startFrameDecoding, since it logically happens
afterwards.

+    void startFrameDecoding(SegmentReader&, size_t);
+
+#if USE(QCMSLIB)
+    std::unique_ptr<png_byte[]> m_rowBuffer;
+#endif
+};
+
+};
+
+#endif