Struct Reader 

pub struct Reader {
    pub hardlinks: HashMap<String, InodeNumber>,
    /* private fields */
}

Read-only ext4 filesystem reader.

Parses the superblock, lazily reads group descriptors and inodes, and maintains a FileTree that mirrors the on-disk directory hierarchy.

Fields

hardlinks: HashMap<String, InodeNumber>

Paths that are hard links to already-seen inodes. Key: path string (e.g. “usr/bin/link”), Value: target inode number.

Implementations

impl Reader

pub fn new(path: &Path) -> ReadResult<Self>

Open an ext4 disk image at path and build the in-memory file tree.

The constructor:

1. Reads and validates the superblock.
2. BFS-traverses the directory tree from the root inode.
3. Records hard links (paths whose inode was already visited).
4. Reads extent information for every discovered entry.

pub fn superblock(&self) -> &SuperBlock

Borrow the parsed superblock.

pub fn tree(&self) -> &FileTree

Borrow the in-memory file tree.

pub fn get_group_descriptor( &mut self, number: u32, ) -> ReadResult<GroupDescriptor>

Get a group descriptor, reading from disk on first access.

pub fn get_inode(&mut self, number: u32) -> ReadResult<Inode>

Get an inode, reading from disk on first access.

pub fn children_of( &mut self, number: InodeNumber, ) -> ReadResult<Vec<(String, InodeNumber)>>

List the children of a directory inode (public wrapper around [get_dir_entries]).

impl Reader

pub fn exists(&mut self, path: &str) -> bool

Check whether path exists in this ext4 filesystem.

pub fn stat(&mut self, path: &str) -> ReadResult<(InodeNumber, Inode)>

Return (inode_number, inode) for the given path, following symlinks.

pub fn stat_no_follow(&mut self, path: &str) -> ReadResult<(InodeNumber, Inode)>

Return (inode_number, inode) for the given path without following the final symlink component.

pub fn list_dir(&mut self, path: &str) -> ReadResult<Vec<String>>

List a directory’s entries (names only, excluding “.” and “..”).

pub fn read_file( &mut self, path: &str, offset: u64, count: Option<usize>, ) -> ReadResult<Vec<u8>>

Read file contents at path starting at offset.

If count is None, reads to EOF. Returns the bytes read (may be shorter than requested if the file is smaller).

pub fn read_file_into( &mut self, path: &str, buf: &mut [u8], offset: u64, ) -> ReadResult<usize>

Read file contents into a pre-allocated buffer. Returns the number of bytes actually written to buf (may be less than buf.len() at EOF).