task: move Scheduler into a trait, define static-sized scheduler implementation, expose as a system task runner in platform

src/main.rs

@@ -10,7 +10,7 @@ mod mappings;
 mod buffers;
 
 use crate::platform::{DefaultBoard, Board};
-use crate::task::{Task, Scheduler};
+use crate::task::{FixedSizeScheduler, Scheduler};
 use crate::render::{Surfaces, Renderer};
 use crate::geometry::Rectangle;
 
@@ -26,20 +26,17 @@ fn main() {
     log::info!("Surface implementation: {}", core::any::type_name_of_val(&output));
 
     log::info!("Creating animations");
-    let mut tasks: Vec<Box<dyn Task + 'static>> = vec![
+    let mut animations = FixedSizeScheduler::new([
         Box::new(animations::IdleTask::new(&mut surfaces)),
         Box::new(animations::TestPattern::new(surfaces.new_surface(&Rectangle::everything()).unwrap())),
     ];
 
-    tasks.append(&mut board.system_tasks());
+    let mut renderer = FixedSizeScheduler::new([Box::new(Renderer::new(output, surfaces))]);
-    tasks.push(Box::new(Renderer::new(output, surfaces)));
-
-    let mut runner = Scheduler::new(tasks);
-
-    log::info!("Runner ready: {:?}", runner);
 
     log::info!("Ready to rock and roll");
     loop {
-        runner.tick();
+        animations.tick();
+        system.tick();
+        renderer.tick();
     }
 }

src/platform/esp32.rs

@@ -18,6 +18,7 @@ use rgb::Rgb;
 
 use super::Board;
 
+use crate::task::FixedSizeScheduler;
 use crate::task::Task;
 use crate::buffers::{Pixbuf, SurfacePool};
 use crate::mappings::StrideMapping;
@@ -34,12 +35,14 @@ use crate::buffers::SimpleSurface as SurfaceType;
 pub struct Esp32Board<'a> {
     output: Option<<Self as Board>::Output>,
     surfaces: Option<SurfacePool<SurfaceType>>,
-    tasks: Option<Vec<Box<dyn Task>>>
+    sys_loop: EspSystemEventLoop,
+    modem: Option<Modem>,
 }
 
 impl<'a> Board for Esp32Board<'a> {
     type Output = StrideOutput<[Rgb<u8>; 310], FastWs2812Esp32Rmt<'a>>;
     type Surfaces = SurfacePool<SurfaceType>;
+    type Scheduler = FixedSizeScheduler<2>;
     
     fn take() -> Self {
         // It is necessary to call this function once. Otherwise some patches to the runtime
@@ -51,7 +54,6 @@ impl<'a> Board for Esp32Board<'a> {
 
         let peripherals = Peripherals::take().unwrap();
         let sys_loop = EspSystemEventLoop::take().unwrap();
-        let nvs = EspDefaultNvsPartition::take().unwrap();
 
         let channel = peripherals.rmt.channel0;
         let pins = peripherals.pins;
@@ -74,10 +76,6 @@ impl<'a> Board for Esp32Board<'a> {
             }
         };
 
-        let tasks: Vec<Box<dyn Task>> = vec![
-            Box::new(WifiTask::new(peripherals.modem, sys_loop.clone(), &nvs)),
-        ];
-
         const POWER_VOLTS : u32 = 5;
         const POWER_MA : u32 = 500;
         const MAX_POWER_MW : u32 = POWER_VOLTS * POWER_MA;
@@ -92,7 +90,8 @@ impl<'a> Board for Esp32Board<'a> {
         Esp32Board {
             surfaces: Some(SurfacePool::new()),
             output: Some(output),
-            tasks: Some(tasks),
+            modem: Some(peripherals.modem),
+            sys_loop: sys_loop.clone(),
         }
     }
 
@@ -104,8 +103,11 @@ impl<'a> Board for Esp32Board<'a> {
         self.surfaces.take().unwrap()
     }
 
-    fn system_tasks(&mut self) -> Vec<Box<dyn Task>> {
+    fn system_tasks(&mut self) -> Self::Scheduler {
-        self.tasks.take().unwrap()
+        let nvs = EspDefaultNvsPartition::take().unwrap();
+        FixedSizeScheduler::new([
+            Box::new(WifiTask::new(self.modem.take().unwrap(), self.sys_loop.clone(), &nvs)),
+        ])
     }
 }
 

src/platform/mod.rs

@@ -9,14 +9,15 @@ pub mod esp32;
 pub type DefaultBoard = esp32::Esp32Board;
 
 use crate::render::{Output, Surfaces};
-use crate::task::Task;
+use crate::task::Scheduler;
 
 pub trait Board {
     type Output: Output;
     type Surfaces: Surfaces;
+    type Scheduler: Scheduler;
 
     fn take() -> Self;
     fn output(&mut self) -> Self::Output;
     fn surfaces(&mut self) -> Self::Surfaces;
-    fn system_tasks(&mut self) -> Vec<Box<dyn Task>>;
+    fn system_tasks(&mut self) -> Self::Scheduler;
 }

src/task.rs

@@ -77,25 +77,35 @@ impl ScheduledTask {
 }
 
 #[derive(Debug)]
-pub struct Scheduler {
+pub struct FixedSizeScheduler<const TASK_COUNT: usize> {
-    tasks: Vec<ScheduledTask>,
+    tasks: [Option<ScheduledTask>; TASK_COUNT],
 }
 
-impl Scheduler {
+impl<const TASK_COUNT: usize> FixedSizeScheduler<TASK_COUNT> {
-    pub fn new(tasks: Vec<Box<dyn Task>>) -> Self {
+    pub fn new(tasks: [Box<dyn Task>; TASK_COUNT]) -> Self {
-        let mut scheduled = Vec::new();
+        let mut scheduled = [const { None }; TASK_COUNT];
+        let mut idx = 0;
         for task in tasks {
-            log::info!("Scheduling task {} {:?}", task.name(), task);
+            scheduled[idx] = Some(ScheduledTask::new(task));
-            scheduled.push(ScheduledTask::new(task));
+            idx += 1;
         }
-        Scheduler {
+        FixedSizeScheduler {
             tasks: scheduled
         }
     }
+}
 
-    pub fn tick(&mut self) {
+impl<const TASK_COUNT: usize> Scheduler for FixedSizeScheduler<TASK_COUNT> {
-        for task in &mut self.tasks {
+    fn tick(&mut self) {
-            task.tick();
+        for slot in &mut self.tasks {
+            match slot {
+                Some(task) => task.tick(),
+                _ => ()
+            }
         }
     }
 }
+
+pub trait Scheduler {
+    fn tick(&mut self);
+}