Source/WebCore/platform/graphics/ByteArrayPixelBuffer.h

/*
 * Copyright (C) 2022 Apple Inc.  All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
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#pragma once

#include "PixelBuffer.h"
#include <JavaScriptCore/Uint8ClampedArray.h>

namespace WebCore {

class ByteArrayPixelBuffer : public PixelBuffer {
public:
    WEBCORE_EXPORT static Ref<ByteArrayPixelBuffer> create(const PixelBufferFormat&, const IntSize&, JSC::Uint8ClampedArray&);

    WEBCORE_EXPORT static RefPtr<ByteArrayPixelBuffer> tryCreate(const PixelBufferFormat&, const IntSize&);
    WEBCORE_EXPORT static RefPtr<ByteArrayPixelBuffer> tryCreate(const PixelBufferFormat&, const IntSize&, Ref<JSC::ArrayBuffer>&&);

    JSC::Uint8ClampedArray& data() const { return m_data.get(); }
    Ref<JSC::Uint8ClampedArray>&& takeData() { return WTFMove(m_data); }

    RefPtr<PixelBuffer> createScratchPixelBuffer(const IntSize&) const override;

    template<class Encoder> void encode(Encoder&) const;
    template<class Decoder> static std::optional<Ref<ByteArrayPixelBuffer>> decode(Decoder&);

private:
    WEBCORE_EXPORT static RefPtr<ByteArrayPixelBuffer> tryCreate(const PixelBufferFormat&, const IntSize&, unsigned dataByteLength);

    ByteArrayPixelBuffer(const PixelBufferFormat&, const IntSize&, Ref<JSC::Uint8ClampedArray>&&);

    bool isByteArrayPixelBuffer() const override { return true; }

    Ref<JSC::Uint8ClampedArray> m_data;
};

template<class Encoder> void ByteArrayPixelBuffer::encode(Encoder& encoder) const
{
    ASSERT(m_data->byteLength() == (m_size.area() * 4));

    encoder << m_format;
    encoder << m_size;
    encoder.encodeFixedLengthData(m_data->data(), m_data->byteLength(), 1);
}

template<class Decoder> std::optional<Ref<ByteArrayPixelBuffer>> ByteArrayPixelBuffer::decode(Decoder& decoder)
{
    std::optional<PixelBufferFormat> format;
    decoder >> format;
    if (!format)
        return std::nullopt;

    // FIXME: Support non-8 bit formats.
    if (!(format->pixelFormat == PixelFormat::RGBA8 || format->pixelFormat == PixelFormat::BGRA8))
        return std::nullopt;

    std::optional<IntSize> size;
    decoder >> size;
    if (!size)
        return std::nullopt;

    auto computedBufferSize = PixelBuffer::computeBufferSize(*format, *size);
    if (computedBufferSize.hasOverflowed())
        return std::nullopt;

    auto bufferSize = computedBufferSize;
    if (!decoder.template bufferIsLargeEnoughToContain<uint8_t>(bufferSize))
        return std::nullopt;

    auto result = ByteArrayPixelBuffer::tryCreate(WTFMove(*format), *size, bufferSize);
    if (!result)
        return std::nullopt;

    if (!decoder.decodeFixedLengthData(result->m_data->data(), result->m_data->byteLength(), 1))
        return std::nullopt;

    return result.releaseNonNull();
}

} // namespace WebCore

SPECIALIZE_TYPE_TRAITS_BEGIN(WebCore::ByteArrayPixelBuffer)
    static bool isType(const WebCore::PixelBuffer& pixelBuffer) { return pixelBuffer.isByteArrayPixelBuffer(); }
SPECIALIZE_TYPE_TRAITS_END()