85 lines
2.4 KiB
Rust
85 lines
2.4 KiB
Rust
use std::marker::PhantomData;
|
|
use std::sync::{Condvar, Mutex};
|
|
|
|
use super::{raw, Spawner};
|
|
|
|
/// Single-threaded std-based executor.
|
|
pub struct Executor {
|
|
inner: raw::Executor,
|
|
not_send: PhantomData<*mut ()>,
|
|
signaler: &'static Signaler,
|
|
}
|
|
|
|
impl Executor {
|
|
/// Create a new Executor.
|
|
pub fn new() -> Self {
|
|
let signaler = &*Box::leak(Box::new(Signaler::new()));
|
|
Self {
|
|
inner: raw::Executor::new(
|
|
|p| unsafe {
|
|
let s = &*(p as *const () as *const Signaler);
|
|
s.signal()
|
|
},
|
|
signaler as *const _ as _,
|
|
),
|
|
not_send: PhantomData,
|
|
signaler,
|
|
}
|
|
}
|
|
|
|
/// Run the executor.
|
|
///
|
|
/// The `init` closure is called with a [`Spawner`] that spawns tasks on
|
|
/// this executor. Use it to spawn the initial task(s). After `init` returns,
|
|
/// the executor starts running the tasks.
|
|
///
|
|
/// To spawn more tasks later, you may keep copies of the [`Spawner`] (it is `Copy`),
|
|
/// for example by passing it as an argument to the initial tasks.
|
|
///
|
|
/// This function requires `&'static mut self`. This means you have to store the
|
|
/// Executor instance in a place where it'll live forever and grants you mutable
|
|
/// access. There's a few ways to do this:
|
|
///
|
|
/// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
|
|
/// - a `static mut` (unsafe)
|
|
/// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
|
|
///
|
|
/// This function never returns.
|
|
pub fn run(&'static mut self, init: impl FnOnce(Spawner)) -> ! {
|
|
init(self.inner.spawner());
|
|
|
|
loop {
|
|
unsafe { self.inner.poll() };
|
|
self.signaler.wait()
|
|
}
|
|
}
|
|
}
|
|
|
|
struct Signaler {
|
|
mutex: Mutex<bool>,
|
|
condvar: Condvar,
|
|
}
|
|
|
|
impl Signaler {
|
|
fn new() -> Self {
|
|
Self {
|
|
mutex: Mutex::new(false),
|
|
condvar: Condvar::new(),
|
|
}
|
|
}
|
|
|
|
fn wait(&self) {
|
|
let mut signaled = self.mutex.lock().unwrap();
|
|
while !*signaled {
|
|
signaled = self.condvar.wait(signaled).unwrap();
|
|
}
|
|
*signaled = false;
|
|
}
|
|
|
|
fn signal(&self) {
|
|
let mut signaled = self.mutex.lock().unwrap();
|
|
*signaled = true;
|
|
self.condvar.notify_one();
|
|
}
|
|
}
|