Struct FencingToken 

pub struct FencingToken(pub u64);

A packed monotonically increasing fencing token that uniquely identifies a write epoch.

Encoded as a single u64:

• High 32 bits = Raft term (capped at u32::MAX for compactness; terms exceeding u32::MAX are exceedingly unlikely in any realistic deployment).
• Low 32 bits = per-term monotonic sequence number.

Each time a node becomes leader it resets the sequence to zero and bumps the term component via FencingToken::new_leader_term. Storage backends and followers use the token to reject stale writes from former leaders: a write is stale when its token’s term is less than the current term, or the term matches but the sequence has been superseded by a higher-sequence write in the same term.

Format

[term: 32 bits][seq: 32 bits]

Tuple Fields

0: u64

Implementations

impl FencingToken

pub fn new(term: u32, seq: u32) -> Self

Pack term and seq into a new fencing token.

pub fn term(self) -> u32

Extract the term component (high 32 bits).

pub fn seq(self) -> u32

Extract the sequence component (low 32 bits).

pub fn raw(self) -> u64

Return the raw u64 representation.

pub fn bump_seq(self) -> Self

Return a new token with the sequence number incremented by one, keeping the term unchanged.

Wraps on u32 overflow (extremely unlikely in practice).

pub fn new_leader_term(term: u32) -> Self

Return a fresh token for a new leader term; the sequence number resets to 0.

Trait Implementations

impl Clone for FencingToken

fn clone(&self) -> FencingToken

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for FencingToken

impl Debug for FencingToken

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

Formats the value using the given formatter.

impl Default for FencingToken

fn default() -> FencingToken

Returns the “default value” for a type.

impl Eq for FencingToken

impl Hash for FencingToken

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for FencingToken

fn cmp(&self, other: &FencingToken) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for FencingToken

fn eq(&self, other: &FencingToken) -> 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 PartialOrd for FencingToken

fn partial_cmp(&self, other: &FencingToken) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for FencingToken