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#[cfg(feature = "executor-interrupt")]
compile_error!("`executor-interrupt` is not supported with `arch-std`.");
#[cfg(feature = "executor-thread")]
pub use thread::*;
#[cfg(feature = "executor-thread")]
mod thread {
use std::marker::PhantomData;
use std::sync::{Condvar, Mutex};
pub use embassy_executor_macros::main_std as main;
use crate::{Spawner, raw};
#[unsafe(export_name = "__pender")]
fn __pender(context: *mut ()) {
let signaler: &'static Signaler = unsafe { std::mem::transmute(context) };
signaler.signal()
}
/// 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(signaler as *mut Signaler as *mut ()),
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)) -> ! {
self.run_until(init, || false);
unreachable!()
}
/// Run the executor until a flag is raised.
///
/// This function is identical to `Executor::run()` apart from offering a `done` flag to stop execution.
pub fn run_until(&'static mut self, init: impl FnOnce(Spawner), mut done: impl FnMut() -> bool) {
init(self.inner.spawner());
loop {
unsafe { self.inner.poll() };
if done() {
break;
}
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();
}
}
}
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