Struct WaitEvent

Source

pub struct WaitEvent<T>(/* private fields */);

Expand description

Create a wait event object of any type T. To use this wait object in multi-threaded scenario, just clone the object and distribute it.

This wait object is just a wrapper of Mutex and Condvar combination with the suggested pattern (from Rust document) for waiting a value.

There are two ways to wait. The first is just to want until an expected value.

use std::thread;
let wait3 = WaitEvent::new_init(0);
let mut wait_handle = wait3.clone();

thread::spawn(move || {
    for i in 1..=3 {
        wait_handle.set_state(i).unwrap();
    }
});

let timeout = std::time::Duration::from_secs(1);
let r#final = *wait3.wait(Some(timeout), |i| *i == 3).unwrap();
let current = *wait3.value().unwrap();
assert_eq!(r#final, 3);
assert_eq!(current, 3);

The second is to wait and then reset the value to a desired state.

use std::thread;
let wait3 = WaitEvent::new_init(0);
let mut wait_handle = wait3.clone();

thread::spawn(move || {
    for i in 1..=3 {
        wait_handle.set_state(i).unwrap();
    }
});

let timeout = std::time::Duration::from_secs(1);
let r#final = wait3.wait_reset(Some(timeout), || 1, |i| *i == 3).unwrap();
let current = *wait3.value().unwrap();
assert_eq!(r#final, 3);
assert_eq!(current, 1);

Implementations§

Source §

pub fn wait( &self, timeout: Option<Duration>, checker: impl FnMut(&T) -> bool, ) -> Result<MutexGuard<'_, T>>

Wait until the checker returns true, or timed-out from timeout.

§Arguments

timeout - Maximum wait time
checker - Checker function, once it returns true, the wait ends

Source

pub fn wait_reset( &self, timeout: Option<Duration>, reset: impl FnMut() -> T, checker: impl FnMut(&T) -> bool, ) -> Result<T>

Wait until the checker returns true, or timed-out from timeout. If the wait ends from checker condition, the interval value is reset by reset.

§Arguments

timeout - Maximum wait time
reset - Function that provides a reset value
checker - Checker function, once it returns true, the wait ends

§Examples

use sync_wait_object::{WaitEvent, WaitObjectError};

let wait3 = WaitEvent::new_init(0);
let mut wait_handle = wait3.clone();

thread::spawn(move || {
    for i in 1..=3 {
        thread::sleep(Duration::from_millis(50));
        wait_handle.set_state(i).unwrap();
    }
});

let timeout = Duration::from_millis(250);
let r#final = wait3.wait_reset(Some(timeout), || 0, |i| *i == 5);
let current = *wait3.value().unwrap();
assert_eq!(r#final, Err(WaitObjectError::Timeout));
assert_eq!(current, 3);

Source

pub fn wait_with_waiter( &self, timeout: Option<Duration>, checker: impl FnMut(&T) -> bool, ) -> Result<MutexGuard<'_, T>>

Source

pub fn wait_and_reset_with_waiter( &self, timeout: Option<Duration>, checker: impl FnMut(&T) -> bool, reset: impl FnMut() -> T, ) -> Result<T>

Source

pub fn set_state(&mut self, new_state: T) -> Result<()>

Synchronously change state of WaitObject by value

Source

pub fn set_state_func<F>(&mut self, setter: F) -> Result<()>
where F: FnOnce(&T) -> T,

Synchronously change state of WaitObject by a function’s return value

§Example

use sync_wait_object::WaitEvent;

let wait = WaitEvent::new_init(0);
let mut w1 = wait.clone();
let mut w2 = wait.clone();
let mut w3 = wait.clone();

thread::spawn(move || w1.set_state_func(|v| v + 1));
thread::spawn(move || w2.set_state_func(|v| v + 1));
thread::spawn(move || w3.set_state_func(|v| v + 1));

let result = *wait.wait(Some(Duration::from_millis(200)), |v| *v == 3).unwrap();
assert_eq!(result, 3);