src/dawn/native/Blob.cpp

// Copyright 2022 The Dawn & Tint Authors
//
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//    this list of conditions and the following disclaimer in the documentation
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#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "dawn/native/Blob.h"

#include <algorithm>
#include <span>
#include <utility>

#include "dawn/common/Assert.h"
#include "dawn/common/Math.h"
#include "dawn/native/stream/Stream.h"

namespace dawn::native {

// static
Blob Blob::Create(size_t size) {
    if (size > 0) {
        uint8_t* ptr = new uint8_t[size];
        return Blob::UnsafeCreateWithDeleter(ptr, size, [=] { delete[] ptr; });
    } else {
        return Blob();
    }
}

// static
Blob Blob::Create(Blob&& original, size_t offset) {
    Blob result(original.mData.subspan(offset), std::move(original.mDeleter));
    original.mData = {};
    original.mDeleter = nullptr;
    return result;
}

// static
Blob Blob::UnsafeCreateWithDeleter(uint8_t* data, size_t size, std::function<void()> deleter) {
    return Blob({reinterpret_cast<std::byte*>(data), size}, deleter);
}

Blob::Blob() : mData({}), mDeleter({}) {}

Blob::Blob(std::span<std::byte> data, std::function<void()> deleter)
    : mData(data), mDeleter(std::move(deleter)) {}

Blob::Blob(Blob&& rhs) : mData(rhs.mData) {
    mDeleter = std::move(rhs.mDeleter);
    rhs.mData = {};
    rhs.mDeleter = nullptr;
}

Blob& Blob::operator=(Blob&& rhs) {
    if (mDeleter) {
        mDeleter();
    }
    mData = rhs.mData;
    mDeleter = std::move(rhs.mDeleter);
    rhs.mData = {};
    rhs.mDeleter = nullptr;
    return *this;
}

Blob::~Blob() {
    if (mDeleter) {
        mDeleter();
    }
}

bool Blob::Empty() const {
    return mData.empty();
}

std::span<const std::byte> Blob::Data() const {
    return mData;
}

std::span<std::byte> Blob::Data() {
    return mData;
}

const std::byte* Blob::DataPtr() const {
    return mData.data();
}

std::byte* Blob::DataPtr() {
    return mData.data();
}

size_t Blob::Size() const {
    return mData.size();
}

bool Blob::operator==(const Blob& other) const {
    return std::ranges::equal(Data(), other.Data());
}

template <>
void stream::Stream<Blob>::Write(stream::Sink* s, const Blob& b) {
    size_t size = b.Size();
    StreamIn(s, size);
    if (size > 0) {
        std::ranges::copy(b.Data(), s->GetSpace(size).begin());
    }
}

template <>
MaybeError stream::Stream<Blob>::Read(stream::Source* s, Blob* b) {
    size_t size;
    DAWN_TRY(StreamOut(s, &size));
    if (size > 0) {
        std::span<const std::byte> src;
        DAWN_TRY_ASSIGN(src, s->Read(size));
        *b = Blob::Create(size);
        std::ranges::copy(src, b->Data().begin());
    } else {
        *b = Blob();
    }
    return {};
}

}  // namespace dawn::native