Add Timer type

CHANGELOG.md

@@ -4,15 +4,18 @@
 
 ### Added
 
-- Add fallibility to `Clock` methods
+- A `Timer` type supporting one-shot and periodic software timers utilizing a `Clock` implementation
+- `Timer` unit tests
+- Fallibility to `Clock` methods
 - `Instant::duration_until()` with order checking
 - Order checking to `Instant::duration_since()`
 - Bounds checking on `Instant` impls of Add/Sub
 - Changelog back to v0.5.0 release
+- [`crossbeam-utils`](https://crates.io/crates/crossbeam-utils) dev-dependency for scoped threads in tests
 
 ### Changed
 
-- Add `&mut self` to `Clock` functions (make stateful, or at least allow stateful implementations)
+- Add `&self` to `Clock` functions (make stateful, or at least allow stateful implementations)
 - All time-type inner types from signed to unsigned
 - `Instant::duration_since()` return type to `Result`
 - Refactor `examples/nrf52_dk`

Cargo.toml

@@ -22,5 +22,8 @@ panic_rtt = "0.3.0"
 nrf52832-hal = { version = "0.10.0", default-features = false, features = ["rt", "xxAA-package"] }
 mutex-trait = "0.2.0"
 
+[target.'cfg(not(target_arch = "arm"))'.dev-dependencies]
+crossbeam-utils = "0.7.2"
+
 [patch.crates-io]
 cortex-m = { git = "https://github.com/rust-embedded/cortex-m", branch = "mutex_add" }

examples/nrf52_dk/main.rs

@@ -152,12 +152,20 @@ where
         led2.set_high()?;
         led3.set_high()?;
         led4.set_low()?;
-        clock.delay(250_u32.milliseconds()).unwrap();
+        clock
+            .new_timer()
+            .set_duration(250_u32.milliseconds())
+            .start()
+            .wait();
 
         led1.set_high()?;
         led2.set_low()?;
         led3.set_low()?;
         led4.set_high()?;
-        clock.delay(250_u32.milliseconds()).unwrap();
+        clock
+            .new_timer()
+            .set_duration(250_u32.milliseconds())
+            .start()
+            .wait();
     }
 }

src/clock.rs

@@ -1,7 +1,7 @@
 //! The `Clock` trait can be implemented over hardware timers or other time-keeping device
 
-use crate::{time_int::TimeInt, Duration, Instant, Period};
-use core::convert::TryFrom;
+use crate::timer::param;
+use crate::{time_int::TimeInt, Duration, Instant, Period, Timer};
 
 /// Potential `Clock` errors
 #[non_exhaustive]
@@ -28,17 +28,8 @@ pub trait Clock: Sized {
     /// Implementation-specific error returned through [`Error::Other(ImplError)`]
     fn now(&self) -> Result<Instant<Self>, Error<Self::ImplError>>;
 
-    /// Blocking delay
-    ///
-    /// # Errors
-    /// Implementation-specific error returned through [`Error::Other(ImplError)`]
-    fn delay<Dur: Duration>(&self, dur: Dur) -> Result<(), Error<Self::ImplError>>
-    where
-        Self::Rep: TryFrom<Dur::Rep>,
-    {
-        let start = self.now()?;
-        let end = start + dur;
-        while self.now()? < end {}
-        Ok(())
+    /// Spawn a new, `OneShot` [`Timer`] from this clock
+    fn new_timer<Dur: Duration>(&self) -> Timer<param::OneShot, param::Disarmed, Self, Dur> {
+        Timer::<param::None, param::None, Self, Dur>::new(&self)
     }
 }

src/lib.rs

@@ -26,6 +26,8 @@
 //! **Wrapping Clock**: A clock that when at its maximum value, the next count is the minimum
 //! value.
 //!
+//! **Timer**: An entity that counts toward an expiration.
+//!
 //! **Instant**: A specific instant in time ("time-point") read from a clock.
 //!
 //! **Duration**: The difference of two instances. The time that has elapsed since an instant. A
@@ -77,13 +79,15 @@ mod frequency;
 mod instant;
 mod period;
 mod time_int;
+mod timer;
 
 pub use clock::Clock;
 use core::{convert::Infallible, fmt};
 pub use duration::Duration;
 pub use instant::Instant;
 pub use period::Period;
 pub use time_int::TimeInt;
+pub use timer::Timer;
 
 /// Public _traits_
 ///