Struct Directory 

pub struct Directory {
    pub ffs: Weak<FastFileSystemInner>,
    pub inode: TrackedInode,
    pub removed: AtomicBool,
}

Represents a directory, which contains multiple directory entries.

This structure provides access to the directory’s inode, which stores information about the directory’s metadata and contents.

Fields

ffs: Weak<FastFileSystemInner>

Weak reference to the file system reference.

inode: TrackedInode

The inode associated with this directory.

removed: AtomicBool

Whether the directory is removed,

Implementations

impl Directory

pub fn new(inode: TrackedInode, ffs: Weak<FastFileSystemInner>) -> Option<Self>

Creates a new Directory from the given inode.

Arguments

• inode: The tracked inode representing this directory.
• ffs: A weak reference to the owning FastFileSystemInner.

Returns

• Some(Directory): if the provided inode is valid and represents a directory.
• None: if the inode is not of type File::Directory.

pub fn read_dir( &self, ffs: &FastFileSystemInner, ) -> Result<Vec<(InodeNumber, String)>, KernelError>

Reads the contents of the directory.

This function lists all the entries within the directory as a [Vec].

A single entry is a tuple that consists of inode number and file name, that is (InodeNumber, String).

Returns

• Ok(()): If the directory was successfully read.
• Err(Error): An error if the read operation fails.

pub fn find( &self, ffs: &FastFileSystemInner, entry: &str, ) -> Result<InodeNumber, KernelError>

Finds the inode number corresponding to a directory entry by name.

Arguments

• ffs: Reference to the file system’s internal structure.
• entry: The name of the directory entry to search for.

Returns

• Ok(inode_number): if the entry is found in the directory.
• Err(KernelError): if the entry is not found or other errors occurs.

pub fn add_entry( &self, ffs: &Arc<FastFileSystemInner>, entry: &str, ino: InodeNumber, tx: &RunningTransaction<'_>, ) -> Result<(), KernelError>

Adds a new entry to the directory.

Arguments

• ffs: Reference to the file system’s internal structure.
• entry: The name of the new directory entry.
• is_dir: Whether the entry is a subdirectory (true) or a regular file (false).
• tx: A running transaction used to persist metadata changes.

Returns

• Ok(()): if the entry is successfully added.
• Err(KernelError): if an error occurs (e.g., entry already exists or out of space).

pub fn take_entry( &self, ffs: &Arc<FastFileSystemInner>, entry: &str, tx: &RunningTransaction<'_>, ) -> Result<TrackedInode, KernelError>

Takes an existing entry out of the directory.

Arguments

• ffs: Reference to the file system’s internal structure.
• entry: The name of the entry to remove.
• tx: A running transaction used to persist metadata changes.

Returns

• Ok(()): if the entry is successfully removed.
• Err(KernelError): if the entry does not exist or an I/O error occurs.

Trait Implementations

impl Directory for Directory

fn ino(&self) -> InodeNumber

Inode number of the directory.

fn size(&self) -> usize

Returns the size of the file in bytes.

fn link_count(&self) -> usize

Link count of the directory.

fn open_entry(&self, entry: &str) -> Result<File, KernelError>

Opens an entry by name.

Parameters

• entry: The name of the entry to open.

Returns

• Ok(File): The enumerate of the file (e.g., regular file, directory).
• Err(Error): An error if the entry cannot be found or accessed.

fn create_entry(&self, entry: &str, is_dir: bool) -> Result<File, KernelError>

Add an entry by name.

Parameters

• entry: The name of the entry to add.
• is_dir: Indicate whether the entry is directory or not.

Returns

• Ok(()): If the entry was successfully added.
• Err(Error): An error if the add fails.

fn unlink_entry(&self, entry: &str) -> Result<(), KernelError>

Removes a directory entry by name.

Errors

• Returns KernelError::Busy when entry’s Inode number is 1 as it means it’s a root directory.
• Returns KernelError::DirectoryNotEmpty when the entry is a non-empty directory
• Returns KernelError::NoSuchEntry if specified entry does not exists.

Parameters

• entry: The name of the entry to remove.

Returns

• Ok(()): If the entry was successfully removed.
• Err(Error): An error if the removal fails.

fn read_dir(&self) -> Result<Vec<(InodeNumber, String)>, KernelError>

Reads the contents of the directory.

This function lists all the entries within the directory.

Returns

• Ok(()): If the directory was successfully read.
• Err(Error): An error if the read operation fails.

fn removed(&self) -> Result<&AtomicBool, KernelError>

Returns AtomicBool which contains whether directory is removed.

This is important because directory operations against the removed directory will result in undesirable behavior (e.g. unreachable file).

Returns

• Ok(()): If the directory was successfully read.
• Err(Error): An error if the operation fails.