/* Provenance: Chromium FileReaderLoader::ArrayBufferResult after CVE-2019-5786.
 * repo: chromium/chromium
 * commit: ba9748e78ec7e9c0d594e7edf7b2c07ea2a90449
 * parent: 9f3fccdba567f30ea39b08f57d8d5b49cd832b4a
 * commit_url: https://github.com/chromium/chromium/commit/ba9748e78ec7e9c0d594e7edf7b2c07ea2a90449
 * cve: CVE-2019-5786
 * license: BSD-3-Clause
 * function: FileReaderLoader::ArrayBufferResult
 * relpath: third_party/blink/renderer/core/fileapi/file_reader_loader.cc
 */
#include <cstdint>
#include <memory>

enum class FileErrorCode { kOK };

class ArrayBuffer {
 public:
    static void *Create(const void *data, size_t length) {
        (void)data;
        (void)length;
        return nullptr;
    }
};

class DOMArrayBuffer {
 public:
    static DOMArrayBuffer *Create(void *buffer) {
        (void)buffer;
        return nullptr;
    }
};

struct RawData {
    void *ToArrayBuffer() { return nullptr; }
    size_t ByteLength() const { return 0; }
    const void *Data() const { return nullptr; }
};

class FileReaderLoader {
 public:
    DOMArrayBuffer *ArrayBufferResult();

    DOMArrayBuffer *array_buffer_result_ = nullptr;
    std::unique_ptr<RawData> raw_data_;
    FileErrorCode error_code_ = FileErrorCode::kOK;
    bool finished_loading_ = false;

    void AdjustReportedMemoryUsageToV8(int64_t delta) { (void)delta; }
};

DOMArrayBuffer *FileReaderLoader::ArrayBufferResult() {
    if (array_buffer_result_)
        return array_buffer_result_;

    // If the loading is not started or an error occurs, return an empty result.
    if (!raw_data_ || error_code_ != FileErrorCode::kOK)
        return nullptr;

    if (!finished_loading_) {
        return DOMArrayBuffer::Create(ArrayBuffer::Create(raw_data_->Data(), raw_data_->ByteLength()));
    }

    array_buffer_result_ = DOMArrayBuffer::Create(raw_data_->ToArrayBuffer());
    AdjustReportedMemoryUsageToV8(-1 * static_cast<int64_t>(raw_data_->ByteLength()));
    raw_data_.reset();
    return array_buffer_result_;
}