Struct ChangeTracker 

pub struct ChangeTracker { /* private fields */ }

Tracks which components were added, removed, or modified within a tick.

This is a runtime-only structure (not #[contracttype]) that records component mutations as they happen. Systems can query the tracker to skip unchanged entities, improving performance.

Example

use cougr_core::runtime::ChangeTracker;
use soroban_sdk::symbol_short;

let entity_id = 1;
let mut tracker = ChangeTracker::new();
tracker.record_add(entity_id, symbol_short!("pos"));

if tracker.was_added(entity_id, &symbol_short!("pos")) {
    assert_eq!(tracker.change_count(), 1);
}

tracker.clear();
tracker.advance_tick();
assert_eq!(tracker.tick(), 1);

Implementations

impl ChangeTracker

pub fn new() -> Self

Create a new empty change tracker at tick 0.

pub fn record_add(&mut self, entity_id: EntityId, component_type: Symbol)

Record that a component was added to an entity.

pub fn record_remove(&mut self, entity_id: EntityId, component_type: Symbol)

Record that a component was removed from an entity.

pub fn record_modify(&mut self, entity_id: EntityId, component_type: Symbol)

Record that a component was modified on an entity.

pub fn was_added(&self, entity_id: EntityId, component_type: &Symbol) -> bool

Check if a specific component was added to an entity this tick.

pub fn was_removed(&self, entity_id: EntityId, component_type: &Symbol) -> bool

Check if a specific component was removed from an entity this tick.

pub fn was_modified(&self, entity_id: EntityId, component_type: &Symbol) -> bool

Check if a specific component was modified on an entity this tick.

pub fn added_entities_with(&self, component_type: &Symbol) -> Vec<EntityId>

Get all entity IDs that had the given component added this tick.

pub fn modified_entities_with(&self, component_type: &Symbol) -> Vec<EntityId>

Get all entity IDs that had the given component modified this tick.

pub fn removed_entities_with(&self, component_type: &Symbol) -> Vec<EntityId>

Get all entity IDs that had the given component removed this tick.

pub fn clear(&mut self)

Clear all recorded changes. Call this between ticks.

pub fn tick(&self) -> u64

Returns the current tick number.

pub fn advance_tick(&mut self)

Advance the tick counter by one.

pub fn change_count(&self) -> usize

Returns the total number of recorded changes.

Trait Implementations

impl Default for ChangeTracker

fn default() -> Self

Returns the “default value” for a type.