rankmap

Ranked hash table.

A hash-table / binary-heap combined data structure that supports the following operations:

Time complexity

use std::thread;
use std::time::{Duration, Instant};

use rankmap::RankMap;

fn task1() {
    println!("task1 finished")
}

fn task2() {
    println!("task2 finished")
}

fn task3() {
    println!("task3 finished")
}

fn main() {
    let mut scheduler: RankMap<&str, Box<dyn Fn()>, Instant> = RankMap::new();

    let tank_id = "task1";
    let task = Box::new(task1);
    let run_at = Instant::now() + Duration::from_secs(1);
    scheduler.insert(tank_id, task, run_at);

    let tank_id = "task2";
    let task = Box::new(task2);
    let run_at = Instant::now() + Duration::from_secs(2);
    scheduler.insert(tank_id, task, run_at);

    while let Some((task_name, task, run_at)) = scheduler.pop() {
        let backoff = run_at - Instant::now();
        thread::sleep(backoff);
        println!("executing {}", task_name);
        task();
    }

    let tank_id = "task3";
    let task = Box::new(task3);
    let run_at = Instant::now() + Duration::from_secs(1);
    scheduler.insert(tank_id, task, run_at);

    if let Some((task, run_at)) = scheduler.remove(&"task3") {
        println!("task3 cancelled");
    }

    assert!(scheduler.top().is_none());
}

See documentation for more details.