Struct State 

pub struct State<T = i32>
where
    T: ToString,
{ /* private fields */ }

Represents a state container for a value that tracks its current, previous, and before-previous states.

This generic struct allows tracking changes to a value over time, with the ability to store the current value, its previous value, and the value before the previous one. The type T must implement the ToString trait.

Type Parameters

• T - The type of the value being tracked, defaulting to i32 if not specified.

Fields

• before_previous - The value that existed before the previous value.
• previous - The previous value of the state.
• current - The current value of the state.
• transacting - A flag indicating whether a transaction is in progress (to be removed).

/// # Thread Safety

This type is intentionally not thread-safe and will panic if accessed from multiple threads. For multi-threaded applications, use thread-local storage to maintain separate instances per thread.

use std::thread;
use std::cell::RefCell;
use transactional::prelude::*;

thread_local! {
    static LOCAL_STATE: RefCell<State<i32>> = RefCell::new(State::new(0));
}

// Safe usage: each thread accesses its own instance
thread::spawn(|| {
    LOCAL_STATE.with(|state| {
        let mut state = state.borrow_mut();
        // Use state safely within this thread
    });
});

Trait Implementations

impl<T> Debug for State<T>

where T: ToString + Debug,

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

Formats the value using the given formatter.

impl<T> Default for State<T>

where T: ToString,

fn default() -> Self

Returns the “default value” for a type.

impl<T> StateBehavior for State<T>

where T: ToString,

type Item = T

fn get(&self) -> Option<&T>

fn get_previous(&self) -> Option<&T>

fn transact( &mut self, value: Option<Self::Item>, ) -> Transaction<'_, Self::Item, Transacting>

impl<T> StateFactory for State<T>

where T: ToString,

type Item = T

fn new(value: Self::Item) -> State<Self::Item>

impl<T> ThreadSafetyChecker for State<T>

where T: ToString,

fn get_owner_thread_id(&self) -> ThreadId

fn ensure_thread_safety(&self)