fn drop()

in src/sync/mutex.rs [153:188]

• 25 lines of code
• 3 McCabe index (conditional complexity)

    fn drop(&mut self) {
        self.inner = None;

        let mut state = self.mutex.state.borrow_mut();
        trace!(waiters=?state.waiters, "releasing mutex {:p}", self.mutex);
        state.holder = None;

        // Bail out early if we're panicking so we don't try to touch `ExecutionState`
        if ExecutionState::should_stop() {
            return;
        }

        // Unblock every thread waiting on this lock. The scheduler will choose one of them to win
        // the race to this lock, and that thread will re-block all the losers.
        let me = ExecutionState::me();
        state.holder = None;
        for tid in state.waiters.iter() {
            debug_assert_ne!(tid, me);
            ExecutionState::with(|s| {
                let t = s.get_mut(tid);
                debug_assert!(t.blocked());
                t.unblock();
            });
        }

        // Update the Mutex clock with the releasing thread's clock
        ExecutionState::with(|s| {
            let clock = s.increment_clock();
            state.clock.update(clock);
        });

        drop(state);

        // Releasing a lock is a yield point
        thread::switch();
    }