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use super::*;
use channel::select;
use crossbeam_channel as channel;
#[derive(Debug)]
enum TimerMsg {
Schedule(TimerEntry),
Cancel(Uuid),
Stop,
}
#[derive(Clone)]
pub struct TimerRef {
work_queue: channel::Sender<TimerMsg>,
}
impl Timer for TimerRef {
fn schedule_once<F>(&mut self, id: Uuid, timeout: Duration, action: F) -> ()
where
F: FnOnce(Uuid) + Send + 'static,
{
let e = TimerEntry::OneShot {
id,
timeout,
action: Box::new(action),
};
self.work_queue
.send(TimerMsg::Schedule(e))
.unwrap_or_else(|e| eprintln!("Could not send Schedule msg: {:?}", e));
}
fn schedule_periodic<F>(&mut self, id: Uuid, delay: Duration, period: Duration, action: F) -> ()
where
F: Fn(Uuid) + Send + 'static,
{
let e = TimerEntry::Periodic {
id,
delay,
period,
action: Box::new(action),
};
self.work_queue
.send(TimerMsg::Schedule(e))
.unwrap_or_else(|e| eprintln!("Could not send Schedule msg: {:?}", e));
}
fn cancel(&mut self, id: Uuid) {
self.work_queue
.send(TimerMsg::Cancel(id))
.unwrap_or_else(|e| eprintln!("Could not send Cancel msg: {:?}", e));
}
}
pub struct TimerWithThread {
timer_thread: thread::JoinHandle<()>,
work_queue: channel::Sender<TimerMsg>,
}
impl TimerWithThread {
pub fn new() -> io::Result<TimerWithThread> {
let (s, r) = channel::unbounded();
let handle = thread::Builder::new()
.name("timer-thread".to_string())
.spawn(move || {
let timer = TimerThread::new(r);
timer.run();
})?;
let twt = TimerWithThread {
timer_thread: handle,
work_queue: s,
};
Ok(twt)
}
pub fn timer_ref(&self) -> TimerRef {
TimerRef {
work_queue: self.work_queue.clone(),
}
}
pub fn shutdown(self) -> Result<(), ThreadTimerError> {
self.work_queue
.send(TimerMsg::Stop)
.unwrap_or_else(|e| eprintln!("Could not send Stop msg: {:?}", e));
match self.timer_thread.join() {
Ok(_) => Ok(()),
Err(_) => {
eprintln!("Timer thread panicked!");
Err(ThreadTimerError::CouldNotJoinThread)
}
}
}
pub fn shutdown_async(&self) -> Result<(), ThreadTimerError> {
self.work_queue
.send(TimerMsg::Stop)
.unwrap_or_else(|e| eprintln!("Could not send Stop msg: {:?}", e));
Ok(())
}
}
impl fmt::Debug for TimerWithThread {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "<TimerWithThread>")
}
}
#[derive(Debug)]
pub enum ThreadTimerError {
CouldNotSendStopAsync,
CouldNotSendStop(TimerWithThread),
CouldNotJoinThread,
}
pub struct TimerThread {
timer: QuadWheelWithOverflow,
work_queue: channel::Receiver<TimerMsg>,
running: bool,
start: Instant,
last_check: u128,
}
impl TimerThread {
fn new(work_queue: channel::Receiver<TimerMsg>) -> TimerThread {
TimerThread {
timer: QuadWheelWithOverflow::new(),
work_queue,
running: true,
start: Instant::now(),
last_check: 0u128,
}
}
pub fn run(mut self) {
while self.running {
let elap = self.elapsed();
if elap > 0 {
for _ in 0..elap {
self.tick();
}
} else {
match self.work_queue.try_recv() {
Ok(msg) => self.handle_msg(msg),
Err(channel::TryRecvError::Empty) => {
// nothing to tick and nothing in the queue
match self.timer.can_skip() {
Skip::None => {
thread::yield_now();
// if last_check.elapsed().as_nanos() > 800000 {
// // if more than 8/10ms left
// thread::yield_now(); // just let someone else run until the next tick
// } // else hot wait to reduce inaccuracy
}
Skip::Empty => {
// wait until something is scheduled
// don't even need to bother skipping time in the wheel,
// since all times in there are relative
match self.work_queue.recv() {
Ok(msg) => {
self.reset(); // since we waited for an arbitrary time and taking a new timestamp incures no error
self.handle_msg(msg)
}
Err(channel::RecvError) => {
panic!("Timer work_queue unexpectedly shut down!")
}
}
}
Skip::Millis(ms) if ms > 5 => {
let ms = ms - 5; // balance OS scheduler inaccuracy
// wait until something is scheduled but max skip
let timeout = Duration::from_millis(ms as u64);
let res = select! {
recv(self.work_queue) -> msg => msg.ok(),
default(timeout) => None,
};
let elap = self.elapsed();
let longms = ms as u128;
if elap > longms {
// took longer to get rescheduled than we wanted
self.timer.skip(ms);
for _ in 0..(elap - longms) {
self.tick();
}
} else if elap < longms {
// we got woken up early, no need to tick
self.timer.skip(elap as u32)
} else {
// elap == ms
// next action should be a tick, but add the new items first
self.timer.skip(ms);
}
match res {
Some(msg) => self.handle_msg(msg),
None => (), // restart loop
}
}
Skip::Millis(_) => {
thread::yield_now();
// if last_check.elapsed().as_nanos() > 800000 {
// // if more than 8/10ms left
// thread::yield_now(); // just let someone else run until the next tick
// } // else hot wait to reduce inaccuracy
}
}
}
Err(channel::TryRecvError::Disconnected) => {
panic!("Timer work_queue unexpectedly shut down!")
}
}
}
}
}
#[inline(always)]
fn elapsed(&mut self) -> u128 {
let elap = self.start.elapsed().as_millis();
let rel_elap = elap - self.last_check;
self.last_check = elap;
rel_elap
}
#[inline(always)]
fn reset(&mut self) {
self.start = Instant::now();
self.last_check = 0;
}
#[inline(always)]
fn handle_msg(&mut self, msg: TimerMsg) -> () {
match msg {
TimerMsg::Stop => self.running = false,
TimerMsg::Schedule(e) => {
match self.timer.insert(e) {
Ok(_) => (), // ok
Err(TimerError::Expired(e)) => {
self.execute(e);
}
Err(f) => panic!("Could not insert timer entry! {:?}", f),
}
}
TimerMsg::Cancel(id) => match self.timer.cancel(id) {
Ok(_) => (), // ok
Err(TimerError::NotFound) => (), // also ok, might have been triggered already
Err(f) => panic!("Unexpected error cancelling timer! {:?}", f),
},
}
}
#[inline(always)]
fn execute(&mut self, e: TimerEntry) -> () {
match e.execute() {
Some(re_e) => match self.timer.insert(re_e) {
Ok(_) => (), // great
Err(TimerError::Expired(re_e)) => {
// This could happen if someone specifies 0ms period
eprintln!("TimerEntry could not be inserted properly: {:?}", re_e);
}
Err(f) => panic!("Could not insert timer entry! {:?}", f),
},
None => (), // great
}
}
#[inline(always)]
fn tick(&mut self) -> () {
let mut res = self.timer.tick();
for e in res.drain(..) {
self.execute(e);
}
}
}