tokio/runtime/scheduler/
defer.rs

1use std::cell::RefCell;
2use std::task::Waker;
3
4pub(crate) struct Defer {
5    deferred: RefCell<Vec<Waker>>,
6}
7
8impl Defer {
9    pub(crate) fn new() -> Defer {
10        Defer {
11            deferred: RefCell::default(),
12        }
13    }
14
15    pub(crate) fn defer(&self, waker: &Waker) {
16        let mut deferred = self.deferred.borrow_mut();
17
18        // If the same task adds itself a bunch of times, then only add it once.
19        if let Some(last) = deferred.last() {
20            if last.will_wake(waker) {
21                return;
22            }
23        }
24
25        deferred.push(waker.clone());
26    }
27
28    pub(crate) fn is_empty(&self) -> bool {
29        self.deferred.borrow().is_empty()
30    }
31
32    pub(crate) fn wake(&self) {
33        while let Some(waker) = self.deferred.borrow_mut().pop() {
34            waker.wake();
35        }
36    }
37
38    #[cfg(tokio_taskdump)]
39    pub(crate) fn take_deferred(&self) -> Vec<Waker> {
40        let mut deferred = self.deferred.borrow_mut();
41        std::mem::take(&mut *deferred)
42    }
43}
tokio/runtime/scheduler/defer.rs

tokio/runtime/scheduler/
defer.rs
