hiasync 0.2.2

Supports only single-threaded asynchronous runtime
Documentation 
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use crate::{Join, JoinHandle, SchedInfo};
use alloc::boxed::Box;
use alloc::rc::{Rc, Weak};
use core::cell::RefCell;
use core::future::Future;
use core::pin::Pin;
use core::task::{Context, Poll};

#[derive(Copy, Clone, Debug)]
pub enum TaskStat {
    Init,
    Running,
    Aborted,
    End,
}

pub(crate) trait Task {
    fn get_id(&self) -> u64;
    fn abort(&mut self);
    fn run(&mut self, ctx: &mut Context<'_>) -> Poll<()>;
}

pub(crate) struct TaskImpl<T: Future> {
    id: u64,
    stat: TaskStat,
    future: T,
    handle: Weak<dyn Join<T::Output>>,
}

impl<T: Future + 'static> TaskImpl<T> {
    pub(crate) fn with_info(
        future: T,
        info: &Rc<RefCell<SchedInfo>>,
    ) -> (Box<dyn Task>, JoinHandle<T::Output>) {
        let id = info.borrow_mut().new_task_id();
        let handle = JoinHandle::new(info.clone(), id);
        let task = Box::new(TaskImpl {
            id,
            stat: TaskStat::Init,
            future,
            handle: handle.weak(),
        });
        (task, handle)
    }

    pub(crate) fn with_join(
        future: T,
        info: &Rc<RefCell<SchedInfo>>,
        handle: Weak<dyn Join<T::Output>>,
    ) -> Box<dyn Task> {
        let id = info.borrow_mut().new_task_id();
        Box::new(TaskImpl {
            stat: TaskStat::Init,
            id,
            future,
            handle,
        })
    }

    fn set_running(&mut self) {
        if let TaskStat::Init = self.stat {
            self.stat = TaskStat::Running;
            // 这个设置通知JoinHandle
            if let Some(handle) = self.handle.upgrade() {
                handle.set_running(self.id);
            }
        }
    }
}

impl<T: Future + 'static> Task for TaskImpl<T> {
    fn get_id(&self) -> u64 {
        self.id
    }

    fn abort(&mut self) {
        self.stat = TaskStat::Aborted;
        // 这个设置通知JoinHandle
        if let Some(handle) = self.handle.upgrade() {
            handle.set_aborted(self.id);
        }
    }

    fn run(&mut self, ctx: &mut Context<'_>) -> Poll<()> {
        self.set_running();
        let pin = unsafe { Pin::new_unchecked(&mut self.future) };
        match pin.poll(ctx) {
            Poll::Pending => Poll::Pending,
            Poll::Ready(output) => {
                if let Some(handle) = self.handle.upgrade() {
                    handle.set_finished(output, self.id);
                }
                self.stat = TaskStat::End;
                Poll::Ready(())
            }
        }
    }
}