Method nextFile

src/Storages/System/StorageSystemRemoteDataPaths.cpp:260–329

}

bool SystemRemoteDataPathsSource::nextFile()
{
    while (true)
    {
        while (!paths_stack.empty())
        {
            auto & current = paths_stack.back();
            ++current.position;
            /// Move to the next child in the current directory
            if (current.position < static_cast<ssize_t>(current.names.size()))
                break;
            /// Move up to the parent directory if this was the last child
            paths_stack.pop_back();
        }

        /// Done with the current disk?
        if (paths_stack.empty())
            return false;

        const auto current_path = getCurrentPath();

        try
        {
            const auto & disk = disks[current_disk].second;

            /// Stop if current path is a file
            if (disk->existsFile(current_path))
                return true;

            /// Files or directories can disappear due to concurrent operations
            if (!disk->existsFileOrDirectory(current_path))
                continue;

            /// If current path is a directory list its contents and step into it
            std::vector<std::string> children;
            disk->listFiles(current_path, children);

            /// Use current predicate for all children
            const auto & skip_predicate = getCurrentSkipPredicate();
            DirListingAndPosition dir;
            for (const auto & child : children)
                dir.names.push_back({child, skip_predicate});
            dir.position = -1;

            paths_stack.emplace_back(std::move(dir));
        }
        catch (const Exception & e)
        {
            /// Files or directories can disappear due to concurrent operations
            if (e.code() == ErrorCodes::FILE_DOESNT_EXIST ||
                e.code() == ErrorCodes::DIRECTORY_DOESNT_EXIST)
                continue;

            throw;
        }
        catch (const fs::filesystem_error & e)
        {
            /// Files or directories can disappear due to concurrent operations