Move integrated timer queue into time-queue-driver

2 files changed, 11 insertions, 90 deletions

diff --git a/embassy-executor/src/raw/timer_queue.rs b/embassy-executor/src/raw/timer_queue.rs
index e0a22f4d4..46e346c1b 100644
--- a/embassy-executor/src/raw/timer_queue.rs
+++ b/embassy-executor/src/raw/timer_queue.rs
@@ -1,99 +1,25 @@
 //! Timer queue operations.
-use core::cmp::min;
 
-use super::util::SyncUnsafeCell;
+use core::cell::Cell;
+
 use super::TaskRef;
 
 /// An item in the timer queue.
 pub struct TimerQueueItem {
-    next: SyncUnsafeCell<Option<TaskRef>>,
-    expires_at: SyncUnsafeCell<u64>,
-}
+    /// The next item in the queue.
+    pub next: Cell<Option<TaskRef>>,
 
-impl TimerQueueItem {
-    pub(crate) const fn new() -> Self {
-        Self {
-            next: SyncUnsafeCell::new(None),
-            expires_at: SyncUnsafeCell::new(0),
-        }
-    }
+    /// The time at which this item expires.
+    pub expires_at: Cell<u64>,
 }
 
-/// A timer queue, with items integrated into tasks.
-pub struct TimerQueue {
-    head: SyncUnsafeCell<Option<TaskRef>>,
-}
+unsafe impl Sync for TimerQueueItem {}
 
-impl TimerQueue {
-    /// Creates a new timer queue.
-    pub const fn new() -> Self {
+impl TimerQueueItem {
+    pub(crate) const fn new() -> Self {
         Self {
-            head: SyncUnsafeCell::new(None),
-        }
-    }
-
-    /// Schedules a task to run at a specific time.
-    ///
-    /// If this function returns `true`, the called should find the next expiration time and set
-    /// a new alarm for that time.
-    pub fn schedule_wake(&mut self, at: u64, p: TaskRef) -> bool {
-        unsafe {
-            let item = p.timer_queue_item();
-            if item.next.get().is_none() {
-                // If not in the queue, add it and update.
-                let prev = self.head.replace(Some(p));
-                item.next.set(prev);
-            } else if at <= item.expires_at.get() {
-                // If expiration is sooner than previously set, update.
-            } else {
-                // Task does not need to be updated.
-                return false;
-            }
-
-            item.expires_at.set(at);
-            true
-        }
-    }
-
-    /// Dequeues expired timers and returns the next alarm time.
-    ///
-    /// The provided callback will be called for each expired task. Tasks that never expire
-    /// will be removed, but the callback will not be called.
-    pub fn next_expiration(&mut self, now: u64) -> u64 {
-        let mut next_expiration = u64::MAX;
-
-        self.retain(|p| {
-            let item = p.timer_queue_item();
-            let expires = unsafe { item.expires_at.get() };
-
-            if expires <= now {
-                // Timer expired, process task.
-                super::wake_task(p);
-                false
-            } else {
-                // Timer didn't yet expire, or never expires.
-                next_expiration = min(next_expiration, expires);
-                expires != u64::MAX
-            }
-        });
-
-        next_expiration
-    }
-
-    fn retain(&self, mut f: impl FnMut(TaskRef) -> bool) {
-        unsafe {
-            let mut prev = &self.head;
-            while let Some(p) = prev.get() {
-                let item = p.timer_queue_item();
-                if f(p) {
-                    // Skip to next
-                    prev = &item.next;
-                } else {
-                    // Remove it
-                    prev.set(item.next.get());
-                    item.next.set(None);
-                }
-            }
+            next: Cell::new(None),
+            expires_at: Cell::new(0),
         }
     }
 }
diff --git a/embassy-executor/src/raw/util.rs b/embassy-executor/src/raw/util.rs
index e2633658a..c46085e45 100644
--- a/embassy-executor/src/raw/util.rs
+++ b/embassy-executor/src/raw/util.rs
@@ -54,9 +54,4 @@ impl<T> SyncUnsafeCell<T> {
     {
         *self.value.get()
     }
-
-    #[cfg(feature = "integrated-timers")]
-    pub unsafe fn replace(&self, value: T) -> T {
-        core::mem::replace(&mut *self.value.get(), value)
-    }
 }