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CriticalSectionMutex should require Send.

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This commit is contained in:
Dario Nieuwenhuis 2021-02-03 16:29:35 +01:00
parent 42c9a603bb
commit 1879703153
1 changed files with 9 additions and 2 deletions
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11
embassy/src/util/mutex.rs
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@ -13,8 +13,11 @@ use crate::fmt::{assert, panic, *};
pub struct CriticalSectionMutex<T> {
inner: UnsafeCell<T>,
}
unsafe impl<T> Sync for CriticalSectionMutex<T> {}
unsafe impl<T> Send for CriticalSectionMutex<T> {}
// NOTE: A `CriticalSectionMutex` can be used as a channel so the protected data must be `Send`
// to prevent sending non-Sendable stuff (e.g. access tokens) across different
// execution contexts (e.g. interrupts)
unsafe impl<T> Sync for CriticalSectionMutex<T> where T: Send {}
impl<T> CriticalSectionMutex<T> {
/// Creates a new mutex
@ -42,6 +45,10 @@ impl<T> CriticalSectionMutex<T> {
pub struct ThreadModeMutex<T> {
inner: UnsafeCell<T>,
}
// NOTE: ThreadModeMutex only allows borrowing from one execution context ever: thread mode.
// Therefore it cannot be used to send non-sendable stuff between execution contexts, so it can
// be Send+Sync even if T is not Send (unlike CriticalSectionMutex)
unsafe impl<T> Sync for ThreadModeMutex<T> {}
unsafe impl<T> Send for ThreadModeMutex<T> {}