1  use super::Task;
 2  use alloc::collections::VecDeque;
 3  use core::task::{Waker, RawWaker};
 4  use core::task::RawWakerVTable;
 5  use core::task::{Context, Poll};
 6  
 7  pub struct SimpleExecutor {
 8      task_queue: VecDeque<Task>,
 9  }
10  
11  impl SimpleExecutor {
12      pub fn new() -> SimpleExecutor {
13          SimpleExecutor {
14              task_queue: VecDeque::new(),
15          }
16      }
17  
18      pub fn spawn(&mut self, task: Task) {
19          self.task_queue.push_back(task)
20      }
21  
22      pub fn run(&mut self) {
23          while let Some(mut task) = self.task_queue.pop_front() {
24              let waker = dummy_water();
25              let mut context = Context::from_waker(&waker);
26              match task.poll(&mut context) {
27                  Poll::Ready(()) => {}
28                  Poll::Pending => self.task_queue.push_back(task),
29              }
30          }
31      }
32  }
33  
34  fn dummy_raw_waker() -> RawWaker {
35      fn no_op(_: *const ()) {}
36      fn clone(_: *const ()) -> RawWaker {
37          dummy_raw_waker()
38      }
39  
40      let vtable = &RawWakerVTable::new(clone, no_op, no_op, no_op);
41      RawWaker::new(0 as *const (), vtable)
42  }
43  
44  fn dummy_water() -> Waker {
45      unsafe { Waker::from_raw(dummy_raw_waker()) }
46  }