2023-05-31 11:50:50 +08:00

104 lines
3.2 KiB
Rust

//! Timer.
#[cfg(target_arch = "x86_64")]
use crate::arch::x86::timer::{add_timeout_list, TimerCallback, TICK};
use crate::{config::TIMER_FREQ, prelude::*};
use core::{sync::atomic::Ordering, time::Duration};
use spin::Mutex;
#[cfg(target_arch = "x86_64")]
pub use crate::arch::x86::timer::read_monotonic_milli_seconds;
/// A timer invokes a callback function after a specified span of time elapsed.
///
/// A new timer is initially inactive. Only after a timeout value is set with
/// the `set` method can the timer become active and the callback function
/// be triggered.
///
/// Timers are one-shot. If the time is out, one has to set the timer again
/// in order to trigger the callback again.
pub struct Timer {
function: Arc<dyn Fn(Arc<Self>) + Send + Sync>,
inner: Mutex<TimerInner>,
}
#[derive(Default)]
struct TimerInner {
start_tick: u64,
timeout_tick: u64,
timer_callback: Option<Arc<TimerCallback>>,
}
fn timer_callback(callback: &TimerCallback) {
let data = callback.data();
if data.is::<Arc<Timer>>() {
let timer = data.downcast_ref::<Arc<Timer>>().unwrap();
timer.function.call((timer.clone(),));
} else {
panic!("the timer callback is not Timer structure");
}
}
const NANOS_DIVIDE: u64 = 1_000_000_000 / TIMER_FREQ;
impl Timer {
/// Creates a new instance, given a callback function.
pub fn new<F>(f: F) -> Result<Arc<Self>>
where
F: Fn(Arc<Timer>) + Send + Sync + 'static,
{
Ok(Arc::new(Self {
function: Arc::new(f),
inner: Mutex::new(TimerInner::default()),
}))
}
/// Set a timeout value.
///
/// If a timeout value is already set, the timeout value will be refreshed.
///
pub fn set(self: Arc<Self>, timeout: Duration) {
let mut lock = self.inner.lock();
match &lock.timer_callback {
Some(callback) => {
callback.disable();
}
None => {}
}
let tick_count =
timeout.as_secs() * TIMER_FREQ + timeout.subsec_nanos() as u64 / NANOS_DIVIDE;
let tick = TICK.load(Ordering::SeqCst);
lock.start_tick = tick;
lock.timeout_tick = tick + tick_count;
lock.timer_callback = Some(add_timeout_list(tick_count, self.clone(), timer_callback));
}
/// Returns the remaining timeout value.
///
/// If the timer is not set, then the remaining timeout value is zero.
pub fn remain(&self) -> Duration {
let lock = self.inner.lock();
let tick_remain = {
let tick = TICK.load(Ordering::SeqCst) as i64;
lock.timeout_tick as i64 - tick
};
if tick_remain <= 0 {
Duration::new(0, 0)
} else {
let second_count = tick_remain as u64 / TIMER_FREQ;
let remain_count = tick_remain as u64 % TIMER_FREQ;
Duration::new(second_count, (remain_count * NANOS_DIVIDE) as u32)
}
}
/// Clear the timeout value.
pub fn clear(&self) {
let mut lock = self.inner.lock();
if let Some(callback) = &lock.timer_callback {
callback.disable();
}
lock.timeout_tick = 0;
lock.start_tick = 0;
lock.timer_callback = None;
}
}