Enum AccessMode 

pub enum AccessMode {
    RandomAccess,
    Sequential,
}

How the files of a source can be reached — the read-side counterpart of MutationCapability. Returned by Filesystem::access_mode.

This is the forward-scan flag: it tells a caller whether addressing an individual file is cheap (an index / positional structure exists) or requires walking the archive from the start. A single forward pass — a repack, or one walk_* — is always cheap; the distinction matters for random per-file access (list of a deep path, read_file of one entry), which on a Sequential source costs a fresh O(n) scan.

Variants

RandomAccess

The format carries an index or positional structure (inode table, extent maps, a central directory, a seekable device): any file is reachable in roughly constant time via read_at. All real filesystems, indexed archives (zip), and disk-image containers.

Sequential

No index — the format is an ordered stream of entries, so reaching a given file means scanning forward from the start (O(n) per lookup). Sequential archives (tar, cpio, ar) and whole-file-compressed streams. Cheap to walk once; expensive to address repeatedly.

Implementations

impl AccessMode

pub fn requires_forward_scan(self) -> bool

Whether reaching an individual file requires an (expensive) forward scan — true for Sequential. Callers use this to gate or warn before doing random per-file access on such a source.

Trait Implementations

impl Clone for AccessMode

fn clone(&self) -> AccessMode

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for AccessMode

impl Debug for AccessMode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for AccessMode

impl PartialEq for AccessMode

fn eq(&self, other: &AccessMode) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for AccessMode