rename 'event_hub' to 'timer', add doc and simplify

crate/thread/src/event_hub.rs

@@ -1,93 +0,0 @@
-use alloc::collections::VecDeque;
-use core::cmp::{Ordering, PartialOrd};
-
-type Time = usize;
-
-struct Timer<T> {
-    time: Time,
-    data: T,
-}
-
-impl<T> PartialEq for Timer<T> {
-    fn eq(&self, other: &Self) -> bool {
-        self.time.eq(&other.time)
-    }
-}
-
-impl<T> Eq for Timer<T> {}
-
-impl<T> PartialOrd for Timer<T> {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        other.time.partial_cmp(&self.time)
-    }
-}
-
-impl<T> Ord for Timer<T> {
-    fn cmp(&self, other: &Self) -> Ordering {
-        self.partial_cmp(&other).unwrap()
-    }
-}
-
-pub struct EventHub<T> {
-    tick: Time,
-    timers: VecDeque<Timer<T>>,
-}
-
-impl<T: PartialEq> EventHub<T> {
-    pub fn new() -> Self {
-        EventHub {
-            tick: 0,
-            timers: VecDeque::new(),
-        }
-    }
-    pub fn tick(&mut self) {
-        self.tick += 1;
-    }
-    pub fn pop(&mut self) -> Option<T> {
-        match self.timers.front() {
-            None => return None,
-            Some(timer) if timer.time != self.tick => return None,
-            _ => {}
-        };
-        self.timers.pop_front().map(|t| t.data)
-    }
-    pub fn push(&mut self, time_after: Time, data: T) {
-        //debug!("{:?} {:?}", self.tick, time_after);
-        let time = self.tick + time_after;
-        let timer = Timer { time, data };
-        let mut it = self.timers.iter();
-        let mut i : usize = 0;
-        loop {
-            let now = it.next();
-            if now == None {
-                break
-            };
-            if now.unwrap() < &timer {
-                break
-            };
-            i += 1;
-        }
-        self.timers.insert(i, timer);
-    }
-    #[allow(dead_code)]
-    pub fn get_time(&self) -> Time {
-        self.tick
-    }
-    pub fn remove(&mut self, data: T) {
-        let mut it = self.timers.iter();
-        let mut i : usize = 0;
-        loop {
-            let now = it.next();
-            if now == None {
-                break
-            };
-            if now.map(|t| &t.data).unwrap() == &data {
-                break
-            };
-            i += 1;
-        }
-        if i < self.timers.len() {
-            self.timers.remove(i);
-        }
-    }
-}

crate/thread/src/lib.rs

@@ -13,7 +13,7 @@ mod thread_pool;
 mod processor;
 pub mod scheduler;
 pub mod std_thread;
-mod event_hub;
+mod timer;
 mod interrupt;
 
 pub use crate::thread_pool::*;

crate/thread/src/thread_pool.rs

@@ -3,7 +3,7 @@ use alloc::vec::Vec;
 use spin::Mutex;
 use log::*;
 use crate::scheduler::Scheduler;
-use crate::event_hub::EventHub;
+use crate::timer::Timer;
 
 struct Thread {
     status: Status,
@@ -38,7 +38,7 @@ pub trait Context {
 pub struct ThreadPool {
     threads: Vec<Mutex<Option<Thread>>>,
     scheduler: Mutex<Box<Scheduler>>,
-    event_hub: Mutex<EventHub<Event>>,
+    timer: Mutex<Timer<Event>>,
 }
 
 impl ThreadPool {
@@ -46,7 +46,7 @@ impl ThreadPool {
         ThreadPool {
             threads: new_vec_default(max_proc_num),
             scheduler: Mutex::new(scheduler),
-            event_hub: Mutex::new(EventHub::new()),
+            timer: Mutex::new(Timer::new()),
         }
     }
 
@@ -79,9 +79,9 @@ impl ThreadPool {
     /// Return true if time slice == 0.
     /// Called by timer interrupt handler.
     pub fn tick(&self, tid: Tid) -> bool {
-        let mut event_hub = self.event_hub.lock();
-        event_hub.tick();
-        while let Some(event) = event_hub.pop() {
+        let mut timer = self.timer.lock();
+        timer.tick();
+        while let Some(event) = timer.pop() {
             match event {
                 Event::Wakeup(tid) => self.set_status(tid, Status::Ready),
             }
@@ -133,7 +133,7 @@ impl ThreadPool {
             (Status::Ready, Status::Ready) => return,
             (Status::Ready, _) => self.scheduler.lock().remove(tid),
             (Status::Exited(_), _) => panic!("can not set status for a exited process"),
-            (Status::Sleeping, Status::Exited(_)) => self.event_hub.lock().remove(Event::Wakeup(tid)),
+            (Status::Sleeping, Status::Exited(_)) => self.timer.lock().stop(Event::Wakeup(tid)),
             (_, Status::Ready) => self.scheduler.lock().insert(tid),
             _ => {}
         }
@@ -176,7 +176,7 @@ impl ThreadPool {
     pub fn sleep(&self, tid: Tid, time: usize) {
         self.set_status(tid, Status::Sleeping);
         if time != 0 {
-            self.event_hub.lock().push(time, Event::Wakeup(tid));
+            self.timer.lock().start(time, Event::Wakeup(tid));
         }
     }
 

crate/thread/src/timer.rs

@@ -0,0 +1,65 @@
+//! A simple timer
+
+use alloc::collections::VecDeque;
+
+type Time = usize;
+
+struct Event<T> {
+    time: Time,
+    data: T,
+}
+
+/// A simple timer using ordered dequeue
+pub struct Timer<T> {
+    tick: Time,
+    timers: VecDeque<Event<T>>,
+}
+
+impl<T: PartialEq> Timer<T> {
+    /// Create a new timer.
+    pub fn new() -> Self {
+        Timer {
+            tick: 0,
+            timers: VecDeque::new(),
+        }
+    }
+    /// Called on each tick.
+    pub fn tick(&mut self) {
+        self.tick += 1;
+    }
+    /// Pop an expired timer after `tick`.
+    ///
+    /// This must be called after calling `tick`,
+    /// and should be called multiple times until return `None`.
+    pub fn pop(&mut self) -> Option<T> {
+        match self.timers.front() {
+            None => return None,
+            Some(timer) if timer.time != self.tick => return None,
+            _ => {}
+        };
+        self.timers.pop_front().map(|t| t.data)
+    }
+    /// Start a timer with given time interval
+    pub fn start(&mut self, time_after: Time, data: T) {
+        //debug!("{:?} {:?}", self.tick, time_after);
+        let time = self.tick + time_after;
+        let event = Event { time, data };
+        let mut it = self.timers.iter();
+        let mut i : usize = 0;
+        loop {
+            match it.next() {
+                None => break,
+                Some(e) if e.time >= time => break,
+                _ => {}
+            }
+            i += 1;
+        }
+        self.timers.insert(i, event);
+    }
+    /// Stop a timer
+    pub fn stop(&mut self, data: T) {
+        if let Some(i) = self.timers.iter().position(|t| t.data == data) {
+            self.timers.remove(i);
+        }
+    }
+}