src/dawn/wire/ChunkedCommandSerializer.cpp

// Copyright 2020 The Dawn & Tint Authors
//
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#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/439062058): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "dawn/wire/ChunkedCommandSerializer.h"

#include "dawn/common/Assert.h"

namespace dawn::wire {

ChunkedCommandSerializer::ChunkedCommandSerializer(CommandSerializer* serializer)
    : mSerializer(serializer), mMaxAllocationSize(serializer->GetMaximumAllocationSize()) {
    DAWN_ASSERT(mMaxAllocationSize > 0);
}

void ChunkedCommandSerializer::SetCommandSerializerForDisconnect(CommandSerializer* serializer) {
    mSerializer = serializer;
    mMaxAllocationSize = serializer->GetMaximumAllocationSize();
    DAWN_ASSERT(mMaxAllocationSize > 0);
}

void ChunkedCommandSerializer::Flush() {
    mSerializer->Flush();
}

void ChunkedCommandSerializer::SerializeChunkedCommand(const char* allocatedBuffer,
                                                       size_t totalSize) {
    // Constant regarding the size of the WireChunkedCommandCmd that can be computed once.
    static size_t kWireChunkedCmdPrefixSize = ChunkedCommandCmd{0, 0, nullptr, 0}.GetRequiredSize();

    ChunkedCommandCmd cmd;
    cmd.id = mNextChunkedCommandId++;
    cmd.size = totalSize;

    size_t remainingSize = totalSize;
    while (remainingSize > 0) {
        cmd.chunkData = allocatedBuffer;
        cmd.chunkSize = std::min(remainingSize, mMaxAllocationSize - kWireChunkedCmdPrefixSize);
        DAWN_ASSERT(cmd.GetRequiredSize() <= mMaxAllocationSize);

        SerializeCommand(cmd);

        allocatedBuffer += cmd.chunkSize;
        remainingSize -= cmd.chunkSize;
    }
}

}  // namespace dawn::wire