diff --git a/src/lib.rs b/src/lib.rs index dfc5e5226e..7b170fc65b 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -83,6 +83,19 @@ where unsafe { &*self.data.get() } } + /// Like [Resource.claim](struct.Resource.html#method.claim) but returns a + /// `&mut-` reference + pub fn claim_mut<'task, PRIORITY>( + &'static self, + _priority: &'task mut P, + ) -> &'task mut T + where + CEILING: Cmp, + P: Priority, + { + unsafe { &mut *self.data.get() } + } + /// Locks the resource for the duration of the critical section `f` /// /// For the duration of the critical section, tasks whose priority level is diff --git a/tests/cfail/claim_mut.rs b/tests/cfail/claim_mut.rs new file mode 100644 index 0000000000..0d1dffd5aa --- /dev/null +++ b/tests/cfail/claim_mut.rs @@ -0,0 +1,34 @@ +#![feature(const_fn)] + +extern crate cortex_m_srp; + +use cortex_m_srp::{C2, P2, Resource}; + +static R1: Resource = Resource::new(0); + +fn j1(mut prio: P2) { + // OK only one `&mut-` reference to the data + let r1: &mut i32 = R1.claim_mut(&mut prio); +} + +fn j2(prio: P2) { + // OK two `&-` references to the same data + let r1: &i32 = R1.claim(&prio); + let another_r1: &i32 = R1.claim(&prio); +} + +fn j3(mut prio: P2) { + // CAN'T have a `&-` reference and a `&mut-` reference to the same data + let r1: &i32 = R1.claim(&prio); + let another_r1: &mut i32 = R1.claim_mut(&mut prio); + //~^ error +} + +fn j4(mut prio: P2) { + // CAN'T have two `&mut-` references to the same data + let r1: &mut i32 = R1.claim_mut(&mut prio); + let another_r1: &mut i32 = R1.claim_mut(&mut prio); + //~^ error +} + +fn main() {}