| use crate::cell::Cell; |
| |
| pub struct Mutex { |
| // This platform has no threads, so we can use a Cell here. |
| locked: Cell<bool>, |
| } |
| |
| unsafe impl Send for Mutex {} |
| unsafe impl Sync for Mutex {} // no threads on this platform |
| |
| impl Mutex { |
| #[inline] |
| #[rustc_const_stable(feature = "const_locks", since = "1.63.0")] |
| pub const fn new() -> Mutex { |
| Mutex { locked: Cell::new(false) } |
| } |
| |
| #[inline] |
| pub fn lock(&self) { |
| assert_eq!(self.locked.replace(true), false, "cannot recursively acquire mutex"); |
| } |
| |
| #[inline] |
| pub unsafe fn unlock(&self) { |
| self.locked.set(false); |
| } |
| |
| #[inline] |
| pub fn try_lock(&self) -> bool { |
| self.locked.replace(true) == false |
| } |
| } |