From 7fea93148569083ef5b5222b405cedba870fee2b Mon Sep 17 00:00:00 2001
From: ivmarkov <ivan.markov@gmail.com>
Date: Sat, 7 Oct 2023 08:49:30 +0000
Subject: [PATCH] Scoped callbacks

---
 CHANGELOG.md                    |  3 ++-
 src/event_bus.rs                | 35 ++++++++++++++++-----------------
 src/timer.rs                    | 21 ++++++++++----------
 src/utils/asyncify/event_bus.rs | 10 ++++++----
 4 files changed, 36 insertions(+), 33 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c9aadb5..28bc61b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,7 +12,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Upgraded `strum` and `strum-macros` to 0.25
 * OTA: New method: `Ota::finish` that allows to postpone/avoid setting the updated partition as a boot one
 * TimerService: `TimerService::timer` now takes `&self` instead of `&mut self`
-* Breaking change: TimerService: scoped handler: the timer handler now only needs to live as long as the `TimerService::Timer` associated type. Therefore, `TimerService::Timer` is now lifetimed: `TimerService::Timer<'a>`
+* Breaking change: TimerService: scoped handler: the timer callback now only needs to live as long as the `TimerService::Timer` associated type. Therefore, `TimerService::Timer` is now lifetimed: `TimerService::Timer<'a>`
+* Breaking change: EventBus: scoped handler: the subscription callback now only needs to live as long as the `EventBus::Subscription` associated type. Therefore, `EventBus::Subscription` is now lifetimed: `EventBus::Subscription<'a>`
 * Breaking change: OTA: GAT `Ota::Update` now parametric over lifetime and no longer returned by `&mut` ref
 * Breaking change: OTA: `OtaUpdate::abort` and `OtaUpdate::complete` now take `self` instead of `&mut self`
 * Breaking change: MQTT: GAT `Connection::Message` now parametric over lifetime
diff --git a/src/event_bus.rs b/src/event_bus.rs
index 6a1fc2c..7ecdba7 100644
--- a/src/event_bus.rs
+++ b/src/event_bus.rs
@@ -47,39 +47,38 @@ where
 }
 
 pub trait EventBus<P>: ErrorType {
-    type Subscription;
+    type Subscription<'a>;
 
-    fn subscribe(
-        &self,
-        callback: impl for<'a> FnMut(&'a P) + Send + 'static,
-    ) -> Result<Self::Subscription, Self::Error>;
+    fn subscribe<'a, F>(&self, callback: F) -> Result<Self::Subscription<'a>, Self::Error>
+    where
+        F: FnMut(&P) + Send + 'a;
 }
 
-impl<'a, P, E> EventBus<P> for &'a mut E
+impl<'e, P, E> EventBus<P> for &'e E
 where
     E: EventBus<P>,
 {
-    type Subscription = E::Subscription;
+    type Subscription<'a> = E::Subscription<'a>;
 
-    fn subscribe(
-        &self,
-        callback: impl for<'b> FnMut(&'b P) + Send + 'static,
-    ) -> Result<Self::Subscription, Self::Error> {
+    fn subscribe<'a, F>(&self, callback: F) -> Result<Self::Subscription<'a>, Self::Error>
+    where
+        F: FnMut(&P) + Send + 'a,
+    {
         (**self).subscribe(callback)
     }
 }
 
-impl<'a, P, E> EventBus<P> for &'a E
+impl<'e, P, E> EventBus<P> for &'e mut E
 where
     E: EventBus<P>,
 {
-    type Subscription = E::Subscription;
+    type Subscription<'a> = E::Subscription<'a>;
 
-    fn subscribe(
-        &self,
-        callback: impl for<'b> FnMut(&'b P) + Send + 'static,
-    ) -> Result<Self::Subscription, Self::Error> {
-        (*self).subscribe(callback)
+    fn subscribe<'a, F>(&self, callback: F) -> Result<Self::Subscription<'a>, Self::Error>
+    where
+        F: FnMut(&P) + Send + 'a,
+    {
+        (**self).subscribe(callback)
     }
 }
 
diff --git a/src/timer.rs b/src/timer.rs
index c495b75..d1fdabd 100644
--- a/src/timer.rs
+++ b/src/timer.rs
@@ -70,8 +70,9 @@ where
 pub trait TimerService: ErrorType {
     type Timer<'a>: OnceTimer<Error = Self::Error> + PeriodicTimer<Error = Self::Error> + 'a;
 
-    fn timer<'a>(&self, callback: impl FnMut() + Send + 'a)
-        -> Result<Self::Timer<'a>, Self::Error>;
+    fn timer<'a, F>(&self, callback: F) -> Result<Self::Timer<'a>, Self::Error>
+    where
+        F: FnMut() + Send + 'a;
 }
 
 impl<S> TimerService for &S
@@ -80,10 +81,10 @@ where
 {
     type Timer<'a> = S::Timer<'a>;
 
-    fn timer<'a>(
-        &self,
-        callback: impl FnMut() + Send + 'a,
-    ) -> Result<Self::Timer<'a>, Self::Error> {
+    fn timer<'a, F>(&self, callback: F) -> Result<Self::Timer<'a>, Self::Error>
+    where
+        F: FnMut() + Send + 'a,
+    {
         (*self).timer(callback)
     }
 }
@@ -94,10 +95,10 @@ where
 {
     type Timer<'a> = S::Timer<'a>;
 
-    fn timer<'a>(
-        &self,
-        callback: impl FnMut() + Send + 'a,
-    ) -> Result<Self::Timer<'a>, Self::Error> {
+    fn timer<'a, F>(&self, callback: F) -> Result<Self::Timer<'a>, Self::Error>
+    where
+        F: FnMut() + Send + 'a,
+    {
         (**self).timer(callback)
     }
 }
diff --git a/src/utils/asyncify/event_bus.rs b/src/utils/asyncify/event_bus.rs
index 36f51e2..bf374d4 100644
--- a/src/utils/asyncify/event_bus.rs
+++ b/src/utils/asyncify/event_bus.rs
@@ -150,11 +150,13 @@ where
     CV: RawCondvar + Send + Sync + 'static,
     CV::RawMutex: Send + Sync + 'static,
 {
-    pub fn subscribe<P>(&self) -> Result<AsyncSubscription<CV, P, E::Subscription>, E::Error>
+    pub fn subscribe<P>(
+        &self,
+    ) -> Result<AsyncSubscription<CV, P, E::Subscription<'static>>, E::Error>
     where
         P: Clone + Send + 'static,
         E: crate::event_bus::EventBus<P>,
-        E::Subscription: Send + 'static,
+        E::Subscription<'static>: Send + 'static,
     {
         let state = Arc::new((
             Mutex::new(SubscriptionState {
@@ -317,9 +319,9 @@ mod async_traits_impl {
         CV::RawMutex: Send + Sync + 'static,
         P: Clone + Send + 'static,
         E: crate::event_bus::EventBus<P>,
-        E::Subscription: Send + 'static,
+        for<'a> E::Subscription<'a>: Send + 'static,
     {
-        type Subscription = AsyncSubscription<CV, P, E::Subscription>;
+        type Subscription = AsyncSubscription<CV, P, E::Subscription<'static>>;
 
         fn subscribe(&self) -> Result<Self::Subscription, Self::Error> {
             AsyncEventBus::subscribe(self)