Crate qubit_state_machine 

Qubit State Machine

A small, thread-safe finite state machine for Rust.

This crate is intentionally compact. It stores immutable transition rules and applies events to an AtomicRef through a compare-and-swap executor.

Examples

use qubit_state_machine::{AtomicRef, StateMachine};

#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
enum State {
    New,
    Running,
    Done,
}

#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
enum Event {
    Start,
    Finish,
}

let machine = StateMachine::builder()
    .add_states(&[State::New, State::Running, State::Done])
    .set_initial_state(State::New)
    .set_final_state(State::Done)
    .add_transition(State::New, Event::Start, State::Running)
    .add_transition(State::Running, Event::Finish, State::Done)
    .build()
    .expect("state machine should be valid");

let state = AtomicRef::from_value(State::New);
assert_eq!(machine.trigger(&state, Event::Start).unwrap(), State::Running);
assert_eq!(*state.load(), State::Running);

Author

Haixing Hu

Structs

AtomicRef

Atomic reference type.

StateMachine

Immutable finite state machine rules.

StateMachineBuilder

Builder used to define and validate finite state machine rules.

Transition

A directed transition in a finite state machine.

Enums

StateMachineBuildError

Error returned when state machine rules are internally inconsistent.

StateMachineError

Error returned when an event cannot be applied to the current state.

Type Aliases

StateMachineResult

Result returned by event-triggering state machine operations.