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put cfg code inside task_from_waker function

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This commit is contained in:
zjp 2024-06-13 07:33:40 +08:00
parent 6b9470be2c
commit b780df5f76
1 changed files with 26 additions and 36 deletions

62
embassy-executor/src/raw/waker.rs
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@ -31,46 +31,36 @@ pub(crate) unsafe fn from_task(p: TaskRef) -> Waker {
/// # Panics /// # Panics
/// ///
/// Panics if the waker is not created by the Embassy executor. /// Panics if the waker is not created by the Embassy executor.
#[cfg(not(feature = "nightly"))]
pub fn task_from_waker(waker: &Waker) -> TaskRef { pub fn task_from_waker(waker: &Waker) -> TaskRef {
// safety: OK because WakerHack has the same layout as Waker. #[cfg(not(feature = "nightly"))]
// This is not really guaranteed because the structs are `repr(Rust)`, it is {
// indeed the case in the current implementation. struct WakerHack {
// TODO use waker_getters when stable. https://github.com/rust-lang/rust/issues/96992 data: *const (),
let hack: &WakerHack = unsafe { core::mem::transmute(waker) }; vtable: &'static RawWakerVTable,
if hack.vtable != &VTABLE { }
panic!("Found waker not created by the Embassy executor. `embassy_time::Timer` only works with the Embassy executor.")
// safety: OK because WakerHack has the same layout as Waker.
// This is not really guaranteed because the structs are `repr(Rust)`, it is
// indeed the case in the current implementation.
// TODO use waker_getters when stable. https://github.com/rust-lang/rust/issues/96992
let hack: &WakerHack = unsafe { core::mem::transmute(waker) };
if hack.vtable != &VTABLE {
panic!("Found waker not created by the Embassy executor. `embassy_time::Timer` only works with the Embassy executor.")
}
// safety: our wakers are always created with `TaskRef::as_ptr`
unsafe { TaskRef::from_ptr(hack.data as *const TaskHeader) }
} }
// safety: our wakers are always created with `TaskRef::as_ptr` #[cfg(feature = "nightly")]
unsafe { TaskRef::from_ptr(hack.data as *const TaskHeader) } {
} let raw_waker = waker.as_raw();
#[cfg(not(feature = "nightly"))] if raw_waker.vtable() != &VTABLE {
struct WakerHack { panic!("Found waker not created by the Embassy executor. `embassy_time::Timer` only works with the Embassy executor.")
data: *const (), }
vtable: &'static RawWakerVTable,
}
/// Get a task pointer from a waker. // safety: our wakers are always created with `TaskRef::as_ptr`
/// unsafe { TaskRef::from_ptr(raw_waker.data() as *const TaskHeader) }
/// This can be used as an optimization in wait queues to store task pointers
/// (1 word) instead of full Wakers (2 words). This saves a bit of RAM and helps
/// avoid dynamic dispatch.
///
/// You can use the returned task pointer to wake the task with [`wake_task`](super::wake_task).
///
/// # Panics
///
/// Panics if the waker is not created by the Embassy executor.
#[cfg(feature = "nightly")]
pub fn task_from_waker(waker: &Waker) -> TaskRef {
let raw_waker = waker.as_raw();
if raw_waker.vtable() != &VTABLE {
panic!("Found waker not created by the Embassy executor. `embassy_time::Timer` only works with the Embassy executor.")
} }
// safety: our wakers are always created with `TaskRef::as_ptr`
unsafe { TaskRef::from_ptr(raw_waker.data() as *const TaskHeader) }
} }