directory

type Directory interface {
	// CreateOrOpen opens the directory specified by path (relative to this
	// Directory), and returns the directory and its contents as a
	// DirectorySubspace. If the directory does not exist, it is created
	// (creating parent directories if necessary).
	//
	// If the byte slice layer is specified and the directory is new, it is
	// recorded as the layer; if layer is specified and the directory already
	// exists, it is compared against the layer specified when the directory was
	// created, and an error is returned if they differ.
	CreateOrOpen(t fdb.Transactor, path []string, layer []byte) (DirectorySubspace, error)

	// Open opens the directory specified by path (relative to this Directory),
	// and returns the directory and its contents as a DirectorySubspace (or ErrDirNotExists
	// error if the directory does not exist, or ErrParentDirDoesNotExist if one of the parent
	// directories in the path does not exist).
	//
	// If the byte slice layer is specified, it is compared against the layer
	// specified when the directory was created, and an error is returned if
	// they differ.
	Open(rt fdb.ReadTransactor, path []string, layer []byte) (DirectorySubspace, error)

	// Create creates a directory specified by path (relative to this
	// Directory), and returns the directory and its contents as a
	// DirectorySubspace (or ErrDirAlreadyExists if the directory already exists).
	//
	// If the byte slice layer is specified, it is recorded as the layer and
	// will be checked when opening the directory in the future.
	Create(t fdb.Transactor, path []string, layer []byte) (DirectorySubspace, error)

	// CreatePrefix behaves like Create, but uses a manually specified byte
	// slice prefix to physically store the contents of this directory, rather
	// than an automatically allocated prefix.
	//
	// If this Directory was created in a root directory that does not allow
	// manual prefixes, CreatePrefix will return an error. The default root
	// directory does not allow manual prefixes.
	CreatePrefix(t fdb.Transactor, path []string, layer []byte, prefix []byte) (DirectorySubspace, error)

	// Move moves the directory at oldPath to newPath (both relative to this
	// Directory), and returns the directory (at its new location) and its
	// contents as a DirectorySubspace. Move will return an error if a directory
	// does not exist at oldPath, a directory already exists at newPath, or the
	// parent directory of newPath does not exist.
	//
	// There is no effect on the physical prefix of the given directory or on
	// clients that already have the directory open.
	Move(t fdb.Transactor, oldPath []string, newPath []string) (DirectorySubspace, error)

	// MoveTo moves this directory to newAbsolutePath (relative to the root
	// directory of this Directory), and returns the directory (at its new
	// location) and its contents as a DirectorySubspace. MoveTo will return an
	// error if a directory already exists at newAbsolutePath or the parent
	// directory of newAbsolutePath does not exist.
	//
	// There is no effect on the physical prefix of the given directory or on
	// clients that already have the directory open.
	MoveTo(t fdb.Transactor, newAbsolutePath []string) (DirectorySubspace, error)

	// Remove removes the directory at path (relative to this Directory), its
	// content, and all subdirectories. Remove returns true if a directory
	// existed at path and was removed, and false if no directory exists at
	// path.
	//
	// Note that clients that have already opened this directory might still
	// insert data into its contents after removal.
	Remove(t fdb.Transactor, path []string) (bool, error)

	// Exists returns true if the directory at path (relative to this Directory)
	// exists, and false otherwise.
	Exists(rt fdb.ReadTransactor, path []string) (bool, error)

	// List returns the names of the immediate subdirectories of the directory
	// at path (relative to this Directory) as a slice of strings. Each string
	// is the name of the last component of a subdirectory's path.
	List(rt fdb.ReadTransactor, path []string) ([]string, error)

	// GetLayer returns the layer specified when this Directory was created.
	GetLayer() []byte

	// GetPath returns the path with which this Directory was opened.
	GetPath() []string
}

type DirectorySubspace interface {
	subspace.Subspace
	Directory
}