Struct ThreadTimer

pub struct ThreadTimer { /* private fields */ }

A simple, cancelable timer that can run a thunk after waiting for an arbitrary duration.

Waiting is accomplished by using a helper thread (the “wait thread”) that listens for incoming wait requests and then executes the requested thunk after blocking for the requested duration. Because each ThreadTimer keeps only one wait thread, each ThreadTimer may only be waiting for a single thunk at a time.

use std::sync::mpsc::{self, TryRecvError};
use std::thread;
use std::time::Duration;
use thread_timer::ThreadTimer;

let (sender, receiver) = mpsc::channel::<bool>();
let timer = ThreadTimer::new();

timer.start(Duration::from_millis(50), move || { sender.send(true).unwrap() }).unwrap();

thread::sleep(Duration::from_millis(60));
assert_eq!(receiver.try_recv(), Ok(true));

If a ThreadTimer is currently waiting to execute a thunk, the wait can be canceled, in which case the thunk will not be run.

use std::sync::mpsc::{self, TryRecvError};
use std::thread;
use std::time::Duration;
use thread_timer::ThreadTimer;

let (sender, receiver) = mpsc::channel::<bool>();
let timer = ThreadTimer::new();

timer.start(Duration::from_millis(50), move || { sender.send(true).unwrap() }).unwrap();

thread::sleep(Duration::from_millis(10));
timer.cancel().unwrap();

thread::sleep(Duration::from_millis(60));
assert_eq!(receiver.try_recv(), Err(TryRecvError::Disconnected));

Implementations

impl ThreadTimer

pub fn new() -> Self

Creates and returns a new ThreadTimer. Spawns a new thread to do the waiting (the “wait thread”).

use thread_timer::ThreadTimer;
let timer = ThreadTimer::new();

pub fn start<F>(&self, dur: Duration, f: F) -> Result<(), TimerStartError>

where F: FnOnce() + Send + 'static,

Start waiting. Wait for dur to elapse then execute f. Will not execute f if the timer is canceled before dur elapses. Returns TimerStartError::AlreadyWaiting if the timer is already waiting to execute a thunk.

use std::sync::mpsc::{self, TryRecvError};
use std::thread;
use std::time::Duration;
use thread_timer::ThreadTimer;

let (sender, receiver) = mpsc::channel::<bool>();
let timer = ThreadTimer::new();

timer.start(Duration::from_millis(50), move || { sender.send(true).unwrap() }).unwrap();
assert_eq!(
  receiver.try_recv(),
  Err(TryRecvError::Empty),
  "Received response before wait elapsed!",
);

thread::sleep(Duration::from_millis(60));
assert_eq!(
  receiver.try_recv(),
  Ok(true),
  "Did not receive response after wait elapsed!",
);

pub fn cancel(&self) -> Result<(), TimerCancelError>

Cancel the current timer (the thunk will not be executed and the timer will be able to start waiting to execute another thunk). This function waits until the wait thread has confirmed that it is ready to start waiting again, so it is safe to call start immediately after calling this function. Returns TimerCancelError::NotWaiting if the timer is not currently waiting.

use std::sync::mpsc::{self, TryRecvError};
use std::thread;
use std::time::Duration;
use thread_timer::ThreadTimer;

let (sender, receiver) = mpsc::channel::<bool>();
let timer = ThreadTimer::new();

timer.start(Duration::from_millis(50), move || { sender.send(true).unwrap() }).unwrap();

// Make sure the wait has actually started before we cancel
thread::sleep(Duration::from_millis(10));
timer.cancel().unwrap();

thread::sleep(Duration::from_millis(60));
assert_eq!(
  receiver.try_recv(),
  // When the wait is canceled, the thunk and its Sender will be dropped
  Err(TryRecvError::Disconnected),
  "Received response from canceled wait!",
);

Trait Implementations

impl Clone for ThreadTimer

fn clone(&self) -> ThreadTimer

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Default for ThreadTimer

fn default() -> Self

Returns the “default value” for a type.