embassy_executor/raw/
timer_queue.rs

1//! Timer queue operations.
2
3use core::cell::Cell;
4
5use super::TaskRef;
6
7#[cfg(feature = "_timer-item-payload")]
8macro_rules! define_opaque {
9    ($size:tt) => {
10        /// An opaque data type.
11        #[repr(align($size))]
12        pub struct OpaqueData {
13            data: [u8; $size],
14        }
15
16        impl OpaqueData {
17            const fn new() -> Self {
18                Self { data: [0; $size] }
19            }
20
21            /// Access the data as a reference to a type `T`.
22            ///
23            /// Safety:
24            ///
25            /// The caller must ensure that the size of the type `T` is less than, or equal to
26            /// the size of the payload, and must ensure that the alignment of the type `T` is
27            /// less than, or equal to the alignment of the payload.
28            ///
29            /// The type must be valid when zero-initialized.
30            pub unsafe fn as_ref<T>(&self) -> &T {
31                &*(self.data.as_ptr() as *const T)
32            }
33        }
34    };
35}
36
37#[cfg(feature = "timer-item-payload-size-1")]
38define_opaque!(1);
39#[cfg(feature = "timer-item-payload-size-2")]
40define_opaque!(2);
41#[cfg(feature = "timer-item-payload-size-4")]
42define_opaque!(4);
43#[cfg(feature = "timer-item-payload-size-8")]
44define_opaque!(8);
45
46/// An item in the timer queue.
47pub struct TimerQueueItem {
48    /// The next item in the queue.
49    ///
50    /// If this field contains `Some`, the item is in the queue. The last item in the queue has a
51    /// value of `Some(dangling_pointer)`
52    pub next: Cell<Option<TaskRef>>,
53
54    /// The time at which this item expires.
55    pub expires_at: Cell<u64>,
56
57    /// Some implementation-defined, zero-initialized piece of data.
58    #[cfg(feature = "_timer-item-payload")]
59    pub payload: OpaqueData,
60}
61
62unsafe impl Sync for TimerQueueItem {}
63
64impl TimerQueueItem {
65    pub(crate) const fn new() -> Self {
66        Self {
67            next: Cell::new(None),
68            expires_at: Cell::new(0),
69            #[cfg(feature = "_timer-item-payload")]
70            payload: OpaqueData::new(),
71        }
72    }
73}
embassy_executor/raw/timer_queue.rs

embassy_executor/raw/
timer_queue.rs
