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| author | Dario Nieuwenhuis <[email protected]> | 2022-08-17 23:40:16 +0200 |
|---|---|---|
| committer | Dario Nieuwenhuis <[email protected]> | 2022-08-18 01:22:30 +0200 |
| commit | 5daa173ce4b153a532b4daa9e94c7a248231f25b (patch) | |
| tree | 2ef0b4d6f9b1c02dac2589e7b57982c20cbc0e66 /embassy-executor/src/executor/raw/waker.rs | |
| parent | 1c5b54a4823d596db730eb476c3ab78110557214 (diff) | |
Split embassy-time from embassy-executor.
Diffstat (limited to 'embassy-executor/src/executor/raw/waker.rs')
| -rw-r--r-- | embassy-executor/src/executor/raw/waker.rs | 53 |
1 files changed, 0 insertions, 53 deletions
diff --git a/embassy-executor/src/executor/raw/waker.rs b/embassy-executor/src/executor/raw/waker.rs deleted file mode 100644 index 6b9c03a62..000000000 --- a/embassy-executor/src/executor/raw/waker.rs +++ /dev/null | |||
| @@ -1,53 +0,0 @@ | |||
| 1 | use core::mem; | ||
| 2 | use core::ptr::NonNull; | ||
| 3 | use core::task::{RawWaker, RawWakerVTable, Waker}; | ||
| 4 | |||
| 5 | use super::{wake_task, TaskHeader}; | ||
| 6 | |||
| 7 | const VTABLE: RawWakerVTable = RawWakerVTable::new(clone, wake, wake, drop); | ||
| 8 | |||
| 9 | unsafe fn clone(p: *const ()) -> RawWaker { | ||
| 10 | RawWaker::new(p, &VTABLE) | ||
| 11 | } | ||
| 12 | |||
| 13 | unsafe fn wake(p: *const ()) { | ||
| 14 | wake_task(NonNull::new_unchecked(p as *mut TaskHeader)) | ||
| 15 | } | ||
| 16 | |||
| 17 | unsafe fn drop(_: *const ()) { | ||
| 18 | // nop | ||
| 19 | } | ||
| 20 | |||
| 21 | pub(crate) unsafe fn from_task(p: NonNull<TaskHeader>) -> Waker { | ||
| 22 | Waker::from_raw(RawWaker::new(p.as_ptr() as _, &VTABLE)) | ||
| 23 | } | ||
| 24 | |||
| 25 | /// Get a task pointer from a waker. | ||
| 26 | /// | ||
| 27 | /// This can be used as an optimization in wait queues to store task pointers | ||
| 28 | /// (1 word) instead of full Wakers (2 words). This saves a bit of RAM and helps | ||
| 29 | /// avoid dynamic dispatch. | ||
| 30 | /// | ||
| 31 | /// You can use the returned task pointer to wake the task with [`wake_task`](super::wake_task). | ||
| 32 | /// | ||
| 33 | /// # Panics | ||
| 34 | /// | ||
| 35 | /// Panics if the waker is not created by the Embassy executor. | ||
| 36 | pub fn task_from_waker(waker: &Waker) -> NonNull<TaskHeader> { | ||
| 37 | // safety: OK because WakerHack has the same layout as Waker. | ||
| 38 | // This is not really guaranteed because the structs are `repr(Rust)`, it is | ||
| 39 | // indeed the case in the current implementation. | ||
| 40 | // TODO use waker_getters when stable. https://github.com/rust-lang/rust/issues/96992 | ||
| 41 | let hack: &WakerHack = unsafe { mem::transmute(waker) }; | ||
| 42 | if hack.vtable != &VTABLE { | ||
| 43 | panic!("Found waker not created by the Embassy executor. `embassy_executor::time::Timer` only works with the Embassy executor.") | ||
| 44 | } | ||
| 45 | |||
| 46 | // safety: we never create a waker with a null data pointer. | ||
| 47 | unsafe { NonNull::new_unchecked(hack.data as *mut TaskHeader) } | ||
| 48 | } | ||
| 49 | |||
| 50 | struct WakerHack { | ||
| 51 | data: *const (), | ||
| 52 | vtable: &'static RawWakerVTable, | ||
| 53 | } | ||
