Struct FileHeader 

pub struct FileHeader {
    pub format_version: u32,
    pub block_size: u32,
    pub root_a: RootPointer,
    pub root_b: RootPointer,
    pub active_root: ActiveRoot,
}

The 4 KB file header for a .luci index file.

Contains magic bytes, format version, block size, two root pointers for atomic commit, and an active root flag. Serializes to exactly HEADER_SIZE bytes.

See [[architecture-storage-format#File Layout]].

Fields

format_version: u32

block_size: u32

root_a: RootPointer

root_b: RootPointer

active_root: ActiveRoot

Implementations

impl FileHeader

pub fn new() -> Self

Create a header for a brand-new index file.

pub fn active_root_pointer(&self) -> &RootPointer

The currently active root pointer.

pub fn inactive_root_pointer(&self) -> &RootPointer

The inactive root pointer (will be overwritten on next commit).

pub fn commit(&mut self, metadata_block: BlockId, checksum: u64)

Prepare the next commit: write new metadata to the inactive root pointer and flip the active flag.

Also re-stamps format_version to the writing binary’s FORMAT_VERSION. A new binary always writes the current on-disk formats (e.g. ColumnType::KeywordBlocked), so the header must advertise the current version even when committing a file created by an older binary — otherwise an old binary could later open the upgraded file and silently misread the new column layout ([[code-must-not-lie]]). This makes any new-binary write a one-way upgrade. The stamp survives only because SingleFileDirectory::commit is refresh-first (it re-reads the on-disk header before this flip); see [[optimization-keyword-dict-offset-index]] and [[project_hnsw_recall_merge_persist_bug]].

pub fn to_bytes(&self) -> [u8; 4096]

Serialize the header to a 4 KB byte buffer.

pub fn from_bytes(buf: &[u8; 4096]) -> Result<Self>

Deserialize a header from a 4 KB byte buffer.

Errors

Returns LuciError::IndexCorrupted if the magic bytes are wrong, the format version is unsupported, or the block size doesn’t match.

Trait Implementations

impl Clone for FileHeader

fn clone(&self) -> FileHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FileHeader

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

Formats the value using the given formatter.

impl Eq for FileHeader

impl PartialEq for FileHeader

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for FileHeader