Struct NxSuperblock 

#[non_exhaustive]
pub struct NxSuperblock {

    pub xid: u64,
    pub uuid: [u8; 16],
    pub block_size: u32,
    pub block_count: u64,
    pub incompatible_features: u64,
    pub xp_desc_base: u64,
    pub xp_desc_blocks: u32,
    pub xp_data_base: u64,
    pub xp_data_blocks: u32,
    pub omap_oid: u64,
    pub spaceman_oid: u64,
    pub reaper_oid: u64,
    pub fs_oids: Vec<u64>,
    /* private fields */
}

A parsed container superblock (subset; #[non_exhaustive] for additive growth).

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

xid: u64

Transaction id of this superblock (nx_o.o_xid).

uuid: [u8; 16]

Container UUID (nx_uuid).

block_size: u32

nx_block_size — the authoritative block size (never assumed).

block_count: u64

nx_block_count.

incompatible_features: u64

nx_incompatible_features — feature bits a reader must understand to mount safely (e.g. NX_INCOMPAT_FUSION); an unrecognised bit means the image cannot be read correctly.

xp_desc_base: u64

Checkpoint descriptor-area base (nx_xp_desc_base) — a block address when contiguous, or a B-tree oid when Self::xp_desc_is_tree.

xp_desc_blocks: u32

Checkpoint descriptor-area length in blocks (nx_xp_desc_blocks, flag bit already masked off).

xp_data_base: u64

Checkpoint data-area base (nx_xp_data_base).

xp_data_blocks: u32

Checkpoint data-area length in blocks (nx_xp_data_blocks, flag bit masked).

omap_oid: u64

Container object-map oid (nx_omap_oid).

spaceman_oid: u64

Space-manager ephemeral oid (nx_spaceman_oid) — resolve to a paddr via the checkpoint map.

reaper_oid: u64

Reaper ephemeral oid (nx_reaper_oid) — resolve to a paddr via the checkpoint map.

fs_oids: Vec<u64>

Volume oids (nx_fs_oid[]), one per APSB volume (trailing zeros trimmed).

Implementations

impl NxSuperblock

pub fn parse(block: &[u8]) -> Result<Self>

Parse and validate an NXSB from a block (checks magic + checksum).

Errors

crate::ApfsError::NoValidSuperblock on a short block or bad magic (carrying the offending magic value); crate::ApfsError::ChecksumMismatch on a Fletcher-64 failure (carrying both the stored and computed checksums).

pub fn xp_desc_is_tree(&self) -> bool

Whether the checkpoint descriptor area is stored as a B-tree (high bit of nx_xp_desc_blocks set) rather than a contiguous run. A contiguous area can be walked directly; a tree-backed one needs B-tree resolution (P2).

pub fn xp_data_is_tree(&self) -> bool

Whether the checkpoint data area is stored as a B-tree.

Trait Implementations

impl Clone for NxSuperblock

fn clone(&self) -> NxSuperblock

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for NxSuperblock

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

Formats the value using the given formatter.