forked from M-Labs/zynq-rs
libasync: replace executor Mutexes with RefCells
this will not run on multi-core.
This commit is contained in:
parent
5b95410244
commit
ea765fc529
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@ -1,17 +1,16 @@
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use core::{
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use core::{
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cell::{Cell, UnsafeCell},
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cell::{RefCell, UnsafeCell},
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future::Future,
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future::Future,
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mem::MaybeUninit,
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mem::MaybeUninit,
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pin::Pin,
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pin::Pin,
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sync::atomic::{self, AtomicBool, Ordering},
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sync::atomic::{AtomicBool, Ordering},
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task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
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task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
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};
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};
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use alloc::{boxed::Box, collections::VecDeque as Deque};
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use alloc::{boxed::Box, collections::VecDeque as Deque};
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//use futures::future::FutureExt;
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//use futures::future::FutureExt;
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use pin_utils::pin_mut;
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use pin_utils::pin_mut;
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use libcortex_a9::mutex::Mutex;
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// TODO: delete
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// TODO: delete
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use libboard_zynq::println;
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//use libboard_zynq::println;
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// NOTE `*const ()` is &AtomicBool
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// NOTE `*const ()` is &AtomicBool
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static VTABLE: RawWakerVTable = {
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static VTABLE: RawWakerVTable = {
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@ -35,16 +34,16 @@ static VTABLE: RawWakerVTable = {
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///
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///
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/// This is a singleton
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/// This is a singleton
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pub struct Executor {
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pub struct Executor {
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in_block_on: Mutex<bool>,
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in_block_on: RefCell<bool>,
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tasks: Mutex<Deque<Task>>,
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tasks: RefCell<Deque<Task>>,
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}
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}
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impl Executor {
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impl Executor {
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/// Creates a new instance of the executor
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/// Creates a new instance of the executor
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pub fn new() -> Self {
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pub fn new() -> Self {
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Self {
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Self {
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in_block_on: Mutex::new(false),
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in_block_on: RefCell::new(false),
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tasks: Mutex::new(Deque::new()),
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tasks: RefCell::new(Deque::new()),
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}
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}
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}
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}
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@ -54,7 +53,7 @@ impl Executor {
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// application will only call `block_on` once on an infinite task
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// application will only call `block_on` once on an infinite task
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// (`Future<Output = !>`)
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// (`Future<Output = !>`)
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{
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{
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let mut in_block_on = self.in_block_on.lock();
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let mut in_block_on = self.in_block_on.borrow_mut();
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if *in_block_on {
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if *in_block_on {
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panic!("nested `block_on`");
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panic!("nested `block_on`");
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}
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}
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@ -70,14 +69,17 @@ impl Executor {
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if ready.load(Ordering::Relaxed) {
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if ready.load(Ordering::Relaxed) {
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ready.store(false, Ordering::Relaxed);
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ready.store(false, Ordering::Relaxed);
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// println!("run block_on");
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let mut cx = Context::from_waker(&waker);
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let mut cx = Context::from_waker(&waker);
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if let Poll::Ready(val) = f.as_mut().poll(&mut cx) {
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if let Poll::Ready(val) = f.as_mut().poll(&mut cx) {
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break val;
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break val;
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}
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}
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// println!("ran block_on");
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}
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}
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// println!("tasks: {}", self.tasks.borrow().len());
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// advance other tasks
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// advance other tasks
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let next_task = self.tasks.lock().pop_front();
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let next_task = self.tasks.borrow_mut().pop_front();
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if let Some(mut task) = next_task {
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if let Some(mut task) = next_task {
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// NOTE we don't need a CAS operation here because `wake` invocations that come from
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// NOTE we don't need a CAS operation here because `wake` invocations that come from
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// interrupt handlers (the only source of 'race conditions' (!= data races)) are
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// interrupt handlers (the only source of 'race conditions' (!= data races)) are
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@ -94,14 +96,16 @@ impl Executor {
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};
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};
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let mut cx = Context::from_waker(&waker);
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let mut cx = Context::from_waker(&waker);
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// this points into a `static` memory so it's already pinned
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// this points into a `static` memory so it's already pinned
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let r = unsafe {
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// println!("run task");
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let ready = unsafe {
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Pin::new_unchecked(&mut *task.f)
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Pin::new_unchecked(&mut *task.f)
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.poll(&mut cx)
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.poll(&mut cx)
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.is_ready()
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.is_ready()
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};
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};
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if !r {
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// println!("ran task, ready={:?}", r);
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if !ready {
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// Task is not finished, requeue
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// Task is not finished, requeue
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self.tasks.lock().push_back(task);
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self.tasks.borrow_mut().push_back(task);
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}
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}
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}
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}
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}
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}
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@ -110,7 +114,7 @@ impl Executor {
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// // interrupt ran (regardless of whether it generated a wake-up or not)
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// // interrupt ran (regardless of whether it generated a wake-up or not)
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// asm::wfe();
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// asm::wfe();
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};
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};
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*self.in_block_on.lock() = false;
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self.in_block_on.replace(false);
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val
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val
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}
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}
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@ -120,13 +124,13 @@ impl Executor {
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pub fn spawn(&self, f: impl Future + 'static) {
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pub fn spawn(&self, f: impl Future + 'static) {
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// NOTE(unsafe) only safe as long as `spawn` is never re-entered and this does not overlap
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// NOTE(unsafe) only safe as long as `spawn` is never re-entered and this does not overlap
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// with operation `(A)` (see `Task::block_on`)
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// with operation `(A)` (see `Task::block_on`)
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self.tasks.lock().push_back(Task::new(f));
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self.tasks.borrow_mut().push_back(Task::new(f));
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}
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}
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}
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}
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pub struct Task {
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pub struct Task {
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ready: AtomicBool,
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ready: AtomicBool,
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f: Box<Future<Output = ()>>,
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f: Box<dyn Future<Output = ()>>,
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}
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}
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impl Task {
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impl Task {
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