pudding_kernel/
semaphore.rs

1use crate::system::*;
2use crate::*;
3
4// Semephore control block
5pub struct Semaphore {
6    queue: TaskQueue,
7    order: Order,
8    count: SemaphoreCount,
9}
10
11impl Semaphore {
12    pub const fn new(init_count: SemaphoreCount, order: Order) -> Self {
13        Semaphore {
14            queue: TaskQueue::new(),
15            order: order,
16            count: init_count,
17        }
18    }
19
20    pub fn signal(&mut self) {
21        let _sc = SystemCall::new();
22        let head = self.queue.pop_front();
23        match head {
24            None => {
25                self.count += 1;
26            }
27            Some(task) => {
28                task.detach_from_timeout();
29                task.attach_to_ready_queue();
30                set_dispatch_reserve_flag();
31            }
32        };
33    }
34
35    pub fn wait(&mut self) {
36        let _sc = SystemCall::new();
37        if self.count > 0 {
38            self.count -= 1;
39        } else {
40            let task = detach_current_task().unwrap();
41            task.attach_to_queue(&mut self.queue, self.order);
42            set_dispatch_reserve_flag();
43        }
44    }
45
46    pub fn polling(&mut self) -> Result<(), Error> {
47        let _sc = SystemCall::new();
48        if self.count > 0 {
49            self.count -= 1;
50            Ok(())
51        } else {
52            Err(Error::Timeout)
53        }
54    }
55
56    pub fn wait_with_timeout(&mut self, time: RelativeTime) -> Result<(), Error> {
57        let task = current_task().unwrap();
58        {
59            let _sc = SystemCall::new();
60            if self.count > 0 {
61                self.count -= 1;
62                task.set_result(Ok(()));
63            } else {
64                let task = detach_current_task().unwrap();
65                task.attach_to_queue(&mut self.queue, self.order);
66                task.attach_to_timeout(time);
67                set_dispatch_reserve_flag();
68            }
69        }
70        task.result()
71    }
72}
pudding_kernel/semaphore.rs

pudding_kernel/
semaphore.rs
