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use std::fmt;
use std::sync::Arc;
use std::sync::atomic::{self, AtomicUsize};
use futures::{self, Async, Future, BoxFuture, IntoFuture};
pub use self::schedule::{Scheduler, SchedulerHandle, SchedulerId};
pub use self::schedule::{with_current_context, Context};
use sync::oneshot::{self, Monitor};
use internal::fiber::Task;
mod schedule;
pub type FiberId = usize;
pub type ContextId = (SchedulerId, FiberId);
pub trait Spawn {
fn spawn_boxed(&self, fiber: BoxFuture<(), ()>);
fn spawn<F>(&self, fiber: F)
where F: Future<Item = (), Error = ()> + Send + 'static
{
self.spawn_boxed(fiber.boxed());
}
fn spawn_fn<F, T>(&self, f: F)
where F: FnOnce() -> T + Send + 'static,
T: IntoFuture<Item = (), Error = ()> + Send + 'static,
T::Future: Send
{
self.spawn(futures::lazy(|| f()))
}
fn spawn_monitor<F, T, E>(&self, f: F) -> Monitor<T, E>
where F: Future<Item = T, Error = E> + Send + 'static,
T: Send + 'static,
E: Send + 'static
{
let (monitored, monitor) = oneshot::monitor();
self.spawn(f.then(move |r| Ok(monitored.exit(r))));
monitor
}
fn boxed(self) -> BoxSpawn
where Self: Sized + Send + 'static
{
BoxSpawn(Box::new(move |fiber| self.spawn_boxed(fiber)))
}
}
pub struct BoxSpawn(Box<Fn(BoxFuture<(), ()>) + Send + 'static>);
impl Spawn for BoxSpawn {
fn spawn_boxed(&self, fiber: BoxFuture<(), ()>) {
(self.0)(fiber);
}
}
impl fmt::Debug for BoxSpawn {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "BoxSpawn(_)")
}
}
#[derive(Debug)]
struct FiberState {
pub fiber_id: FiberId,
task: Task,
parks: usize,
unparks: Arc<AtomicUsize>,
pub in_run_queue: bool,
}
impl FiberState {
pub fn new(fiber_id: FiberId, task: Task) -> Self {
FiberState {
fiber_id: fiber_id,
task: task,
parks: 0,
unparks: Arc::new(AtomicUsize::new(0)),
in_run_queue: false,
}
}
pub fn run_once(&mut self) -> bool {
if self.parks > 0 {
if self.unparks.load(atomic::Ordering::SeqCst) > 0 {
self.parks -= 1;
self.unparks.fetch_sub(1, atomic::Ordering::SeqCst);
}
}
if let Ok(Async::NotReady) = self.task.0.poll() {
false
} else {
true
}
}
pub fn is_runnable(&self) -> bool {
self.parks == 0 || self.unparks.load(atomic::Ordering::SeqCst) > 0
}
pub fn park(&mut self,
scheduler_id: schedule::SchedulerId,
scheduler: schedule::SchedulerHandle)
-> Unpark {
self.parks += 1;
Unpark {
fiber_id: self.fiber_id,
unparks: self.unparks.clone(),
scheduler_id: scheduler_id,
scheduler: scheduler,
}
}
}
#[derive(Debug)]
pub struct Unpark {
fiber_id: FiberId,
unparks: Arc<AtomicUsize>,
scheduler_id: schedule::SchedulerId,
scheduler: schedule::SchedulerHandle,
}
impl Unpark {
pub fn context_id(&self) -> ContextId {
(self.scheduler_id, self.fiber_id)
}
}
impl Drop for Unpark {
fn drop(&mut self) {
let old = self.unparks.fetch_add(1, atomic::Ordering::SeqCst);
if old == 0 {
self.scheduler.wakeup(self.fiber_id);
}
}
}