Method RenameSemantics

cpp/src/arrow/filesystem/azurefs_test.cc:1824–1881

\brief Expected POSIX semantics for the rename operation on multiple scenarios. If the src doesn't exist, the error is always ENOENT, otherwise we are left with the following combinations: 1. src's type a. File b. Directory 2. dest's existence a. NotFound b. File c. Directory - empty - non-empty 3. src path has a trailing slash (or not) 4. dest path has a trailing slash (or not) Limitations: th

  /// \return std::nullopt if success is expected in the scenario or the errno
  /// if failure is expected.
  static std::optional<int> RenameSemantics(FileType src_type, bool src_trailing_slash,
                                            FileType dest_type, bool dest_trailing_slash,
                                            bool dest_is_empty_dir = false,
                                            bool paths_are_equal = false) {
    DCHECK(src_type != FileType::Unknown && dest_type != FileType::Unknown);
    DCHECK(!dest_is_empty_dir || dest_type == FileType::Directory)
        << "dest_is_empty_dir must imply dest_type == FileType::Directory";
    switch (src_type) {
      case FileType::Unknown:
        break;
      case FileType::NotFound:
        return {ENOENT};
      case FileType::File:
        switch (dest_type) {
          case FileType::Unknown:
            break;
          case FileType::NotFound:
            if (src_trailing_slash) {
              return {ENOTDIR};
            }
            if (dest_trailing_slash) {
              // A slash on the destination path requires that it exists,
              // so a confirmation that it's a directory can be performed.
              return {ENOENT};
            }
            return {};
          case FileType::File:
            if (src_trailing_slash || dest_trailing_slash) {
              return {ENOTDIR};
            }
            // The existing file is replaced successfuly.
            return {};
          case FileType::Directory:
            if (src_trailing_slash) {
              return {ENOTDIR};
            }
            return EISDIR;
        }
        break;
      case FileType::Directory:
        switch (dest_type) {
          case FileType::Unknown:
            break;
          case FileType::NotFound:
            // We don't have to care about the slashes when the source is a directory.
            return {};
          case FileType::File:
            return {ENOTDIR};
          case FileType::Directory:
            if (!paths_are_equal && !dest_is_empty_dir) {
              return {ENOTEMPTY};
            }
            return {};
        }
        break;
    }
    Unreachable("Invalid parameters passed to RenameSemantics");
  }