Method readFile

src/IO/PackedFilesReader.cpp:85–103

}

std::unique_ptr<ReadBufferFromFileBase> PackedFilesReader::readFile(
    const DiskPtr & disk,
    const String & data_file_name,
    const String & file_name,
    const ReadSettings & settings,
    std::optional<size_t> read_hint) const
{
    auto it = index.find(file_name);
    if (it == index.end())
        throw Exception(ErrorCodes::FILE_DOESNT_EXIST, "File {} does not exist", file_name);

    const auto & [offset, size] = it->second;

    /// ReadBufferFromFileView doesn't support reading with mmap and direct io methods, because
    /// they require special alignment which cannot be achieved while reading archive file.
    /// So just disable them.
    auto in = disk->readFile(data_file_name, patchSettings(settings), read_hint);
    return std::make_unique<ReadBufferFromFileView>(std::move(in), file_name, offset, offset + size);
}

}