Method getFileSize

src/IO/WithFileSize.cpp:16–22

}

size_t WithFileSize::getFileSize()
{
    if (auto maybe_size = tryGetFileSize())
        return *maybe_size;

    throw Exception(ErrorCodes::UNKNOWN_FILE_SIZE, "Cannot find out file size");
}

template <typename T>
static std::optional<size_t> tryGetFileSize(T & in)