embassy_executor/arch/
std.rs

1#[cfg(feature = "executor-interrupt")]
2compile_error!("`executor-interrupt` is not supported with `arch-std`.");
3
4#[cfg(feature = "executor-thread")]
5pub use thread::*;
6#[cfg(feature = "executor-thread")]
7mod thread {
8    use std::marker::PhantomData;
9    use std::sync::{Condvar, Mutex};
10
11    pub use embassy_executor_macros::main_std as main;
12
13    use crate::{raw, Spawner};
14
15    #[export_name = "__pender"]
16    fn __pender(context: *mut ()) {
17        let signaler: &'static Signaler = unsafe { std::mem::transmute(context) };
18        signaler.signal()
19    }
20
21    /// Single-threaded std-based executor.
22    pub struct Executor {
23        inner: raw::Executor,
24        not_send: PhantomData<*mut ()>,
25        signaler: &'static Signaler,
26    }
27
28    impl Executor {
29        /// Create a new Executor.
30        pub fn new() -> Self {
31            let signaler = Box::leak(Box::new(Signaler::new()));
32            Self {
33                inner: raw::Executor::new(signaler as *mut Signaler as *mut ()),
34                not_send: PhantomData,
35                signaler,
36            }
37        }
38
39        /// Run the executor.
40        ///
41        /// The `init` closure is called with a [`Spawner`] that spawns tasks on
42        /// this executor. Use it to spawn the initial task(s). After `init` returns,
43        /// the executor starts running the tasks.
44        ///
45        /// To spawn more tasks later, you may keep copies of the [`Spawner`] (it is `Copy`),
46        /// for example by passing it as an argument to the initial tasks.
47        ///
48        /// This function requires `&'static mut self`. This means you have to store the
49        /// Executor instance in a place where it'll live forever and grants you mutable
50        /// access. There's a few ways to do this:
51        ///
52        /// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
53        /// - a `static mut` (unsafe)
54        /// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
55        ///
56        /// This function never returns.
57        pub fn run(&'static mut self, init: impl FnOnce(Spawner)) -> ! {
58            init(self.inner.spawner());
59
60            loop {
61                unsafe { self.inner.poll() };
62                self.signaler.wait()
63            }
64        }
65    }
66
67    struct Signaler {
68        mutex: Mutex<bool>,
69        condvar: Condvar,
70    }
71
72    impl Signaler {
73        fn new() -> Self {
74            Self {
75                mutex: Mutex::new(false),
76                condvar: Condvar::new(),
77            }
78        }
79
80        fn wait(&self) {
81            let mut signaled = self.mutex.lock().unwrap();
82            while !*signaled {
83                signaled = self.condvar.wait(signaled).unwrap();
84            }
85            *signaled = false;
86        }
87
88        fn signal(&self) {
89            let mut signaled = self.mutex.lock().unwrap();
90            *signaled = true;
91            self.condvar.notify_one();
92        }
93    }
94}
embassy_executor/arch/std.rs

embassy_executor/arch/
std.rs
