fibers/executor/
in_place.rs

1// Copyright (c) 2016 DWANGO Co., Ltd. All Rights Reserved.
2// See the LICENSE file at the top-level directory of this distribution.
3
4use futures::Future;
5use std::io;
6use std::time;
7
8use super::Executor;
9use fiber::{self, Spawn};
10use io::poll;
11
12/// An executor that executes spawned fibers and I/O event polling on current thread.
13///
14/// # Examples
15///
16/// An example to calculate fibonacci numbers:
17///
18/// ```
19/// # extern crate fibers;
20/// # extern crate futures;
21/// use fibers::{Spawn, Executor, InPlaceExecutor};
22/// use futures::{Async, Future};
23///
24/// fn fib<H: Spawn + Clone>(n: usize, handle: H) -> Box<dyn Future<Item=usize, Error=()> + Send> {
25///     if n < 2 {
26///         Box::new(futures::finished(n))
27///     } else {
28///         let f0 = handle.spawn_monitor(fib(n - 1, handle.clone()));
29///         let f1 = handle.spawn_monitor(fib(n - 2, handle.clone()));
30///         Box::new(f0.join(f1).map(|(a0, a1)| a0 + a1).map_err(|_| ()))
31///     }
32/// }
33///
34/// let mut executor = InPlaceExecutor::new().unwrap();
35/// let mut monitor = executor.spawn_monitor(fib(7, executor.handle()));
36/// loop {
37///     if let Async::Ready(answer) = monitor.poll().unwrap() {
38///         assert_eq!(answer, 13);
39///         return;
40///     } else {
41///         executor.run_once().unwrap();
42///     }
43/// }
44/// ```
45#[derive(Debug)]
46pub struct InPlaceExecutor {
47    scheduler: fiber::Scheduler,
48    poller: poll::Poller,
49}
50impl InPlaceExecutor {
51    /// Creates a new instance of `InPlaceExecutor`.
52    pub fn new() -> io::Result<Self> {
53        let poller = poll::Poller::new()?;
54        Ok(InPlaceExecutor {
55            scheduler: fiber::Scheduler::new(poller.handle()),
56            poller,
57        })
58    }
59}
60impl Executor for InPlaceExecutor {
61    type Handle = InPlaceExecutorHandle;
62    fn handle(&self) -> Self::Handle {
63        InPlaceExecutorHandle {
64            scheduler: self.scheduler.handle(),
65        }
66    }
67    fn run_once(&mut self) -> io::Result<()> {
68        self.scheduler.run_once(false);
69        self.poller.poll(Some(time::Duration::from_millis(1)))?;
70        Ok(())
71    }
72}
73impl Spawn for InPlaceExecutor {
74    fn spawn_boxed(&self, fiber: Box<dyn Future<Item = (), Error = ()> + Send>) {
75        self.handle().spawn_boxed(fiber)
76    }
77}
78
79/// A handle of an `InPlaceExecutor` instance.
80#[derive(Debug, Clone)]
81pub struct InPlaceExecutorHandle {
82    scheduler: fiber::SchedulerHandle,
83}
84impl Spawn for InPlaceExecutorHandle {
85    fn spawn_boxed(&self, fiber: Box<dyn Future<Item = (), Error = ()> + Send>) {
86        self.scheduler.spawn_boxed(fiber)
87    }
88}
fibers/executor/in_place.rs

fibers/executor/
in_place.rs
