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common/PeripheralMutex: remove unsafe API. (#802)

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Following the project's decision that "leak unsafe" APIs are not marked as "unsafe",
update PeripheralMutex to accept non-'static state without unsafe.

Fixes #801
This commit is contained in:
Dario Nieuwenhuis
2022-06-09 21:28:13 +02:00
committed by GitHub
parent 77c7d8f31b
commit db344c2bda
6 changed files with 25 additions and 48 deletions
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26
embassy-hal-common/src/peripheral.rs
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@ -52,33 +52,11 @@ pub(crate) fn can_be_preempted(irq: &impl Interrupt) -> bool {
impl<'a, S: PeripheralState> PeripheralMutex<'a, S> {
/// Create a new `PeripheralMutex` wrapping `irq`, with `init` initializing the initial state.
///
/// self requires `S` to live for `'static`, because if the `PeripheralMutex` is leaked, the
/// interrupt won't be disabled, which may try accessing the state at any time. To use non-`'static`
/// state, see [`Self::new_unchecked`].
///
/// Registers `on_interrupt` as the `irq`'s handler, and enables it.
pub fn new(
irq: S::Interrupt,
storage: &'a mut StateStorage<S>,
init: impl FnOnce() -> S,
) -> Self
where
'a: 'static,
{
// safety: safe because state is `'static`.
unsafe { Self::new_unchecked(irq, storage, init) }
}
/// Create a `PeripheralMutex` without requiring the state is `'static`.
///
/// See also [`Self::new`].
///
/// # Safety
/// The created instance must not be leaked (its `drop` must run).
pub unsafe fn new_unchecked(
irq: S::Interrupt,
storage: &'a mut StateStorage<S>,
init: impl FnOnce() -> S,
) -> Self {
if can_be_preempted(&irq) {
panic!("`PeripheralMutex` cannot be created in an interrupt with higher priority than the interrupt it wraps");
@ -88,10 +66,10 @@ impl<'a, S: PeripheralState> PeripheralMutex<'a, S> {
// Safety: The pointer is valid and not used by anyone else
// because we have the `&mut StateStorage`.
state_ptr.write(init());
unsafe { state_ptr.write(init()) };
irq.disable();
irq.set_handler(|p| {
irq.set_handler(|p| unsafe {
// Safety: it's OK to get a &mut to the state, since
// - We checked that the thread owning the `PeripheralMutex` can't preempt us in `new`.
// Interrupts' priorities can only be changed with raw embassy `Interrupts`,