Struct FeedPosition 

#[non_exhaustive]
pub struct FeedPosition {
    pub generation: u64,
    pub offset: u64,
}

A point in a feed: an offset within one generation’s offset history.

The pair is the whole identity — an offset means nothing outside its generation, so the two travel together: a feed cursor, the tail a consumer resumes at, the position a replica claims at handshake, the cursor a snapshot records. FeedPosition::default() is generation 0, offset 0: the “no continuity claim” a fresh replica presents (no real feed ever runs at generation 0).

use kevy_replicate::feed::FeedPosition;

let at = FeedPosition::new(7, 42);
assert_eq!((at.generation, at.offset), (7, 42));
assert_eq!(FeedPosition::default(), FeedPosition::new(0, 0));

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.

generation: u64

The offset history this position belongs to: an opaque identity, see fresh_generation. 0 = unknown.

use kevy_replicate::feed::FeedSource;
use kevy_replicate::source::ReplicationSource;

let feed = FeedSource::new(9, ReplicationSource::new(1 << 20));
assert_eq!(feed.tail().generation, 9);

offset: u64

The offset within that history.

use kevy_replicate::feed::FeedSource;
use kevy_replicate::source::ReplicationSource;

let mut feed = FeedSource::new(1, ReplicationSource::new(1 << 20));
let set = kevy_resp::Argv::from(vec![b"SET".to_vec(), b"k".to_vec(), b"v".to_vec()]);
feed.source_mut().push_mutation(&set);
assert_eq!(feed.tail().offset, 1); // the next write lands at offset 1

Implementations

impl FeedPosition

pub const fn new(generation: u64, offset: u64) -> FeedPosition

The position at offset in generation.

let at = kevy_replicate::feed::FeedPosition::new(3, 0);
assert_eq!(at.generation, 3);

Trait Implementations

impl Clone for FeedPosition

fn clone(&self) -> FeedPosition

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for FeedPosition

impl Debug for FeedPosition

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

Formats the value using the given formatter.

impl Default for FeedPosition

fn default() -> FeedPosition

Returns the “default value” for a type.

impl Eq for FeedPosition

impl Hash for FeedPosition

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

where __H: Hasher,

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 PartialEq for FeedPosition

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for FeedPosition