Add opt-in handlers for before sleeping and before handling events (Smithay#144)

* Add opt-in handlers for before sleeping and before handling events

* Remove pre_run and fix some missed impls

* Appease the great 📎

* Use an associated constant instead

* Do the borrow outside the loop

* Fix cfged out mistake

* Update documentation to reflect changes

* Actually use the synthetic events

* Add some tests for the new functionality

* Pin `nix` to a lower version

* Rename `before_will_sleep` to `before_sleep`

* Add some more coverage

* Solve review comments

* Restore inconsistencies in formatting

* Remove AdditionalLifetimeEventsRegister

* Remove unused lifetime

* Unencapsulate the refcell

* Address review comments

* Exclude synthetic events from the iterator

* Follow clippy's improvement (?)

Author: DJMcNab

CHANGELOG.md

@@ -6,8 +6,10 @@
 
 - Bump MSRV to 1.63
 - Make signals an optional feature under the `signals` features.
-- Replace the `nix` crate with standard library I/O errors and the `rustix` 
-crate.
+- Replace the `nix` crate with standard library I/O errors and the `rustix` crate.
+- `pre_run` and `post_run` on `EventSource` have been replaced with `before_sleep` and `before_handle_events`, respectively.
+  These are now opt-in through the `NEEDS_EXTRA_LIFECYCLE_EVENTS` associated constant, and occur at slightly different times to
+  the methods they are replacing. This allows greater compatibility with Wayland based event sources.
 
 ## 0.11.0 -- 2023-06-05
 

src/io.rs

@@ -18,11 +18,13 @@ use rustix::fs::{fcntl_getfl, fcntl_setfl, OFlags};
 #[cfg(feature = "futures-io")]
 use futures_io::{AsyncRead, AsyncWrite, IoSlice, IoSliceMut};
 
+use crate::loop_logic::EventIterator;
 use crate::{
     loop_logic::{LoopInner, MAX_SOURCES_MASK},
     sources::EventDispatcher,
     Interest, Mode, Poll, PostAction, Readiness, Token, TokenFactory,
 };
+use crate::{AdditionalLifecycleEventsSet, RegistrationToken};
 
 /// Adapter for async IO manipulations
 ///
@@ -237,30 +239,43 @@ impl<Data> EventDispatcher<Data> for RefCell<IoDispatcher> {
         Ok(PostAction::Continue)
     }
 
-    fn register(&self, _: &mut Poll, _: &mut TokenFactory) -> crate::Result<()> {
+    fn register(
+        &self,
+        _: &mut Poll,
+        _: &mut AdditionalLifecycleEventsSet,
+        _: &mut TokenFactory,
+    ) -> crate::Result<()> {
         // registration is handled by IoLoopInner
         unreachable!()
     }
 
-    fn reregister(&self, _: &mut Poll, _: &mut TokenFactory) -> crate::Result<bool> {
+    fn reregister(
+        &self,
+        _: &mut Poll,
+        _: &mut AdditionalLifecycleEventsSet,
+        _: &mut TokenFactory,
+    ) -> crate::Result<bool> {
         // registration is handled by IoLoopInner
         unreachable!()
     }
 
-    fn unregister(&self, poll: &mut Poll) -> crate::Result<bool> {
+    fn unregister(
+        &self,
+        poll: &mut Poll,
+        _: &mut AdditionalLifecycleEventsSet,
+        _: RegistrationToken,
+    ) -> crate::Result<bool> {
         let disp = self.borrow();
         if disp.is_registered {
             poll.unregister(unsafe { BorrowedFd::borrow_raw(disp.fd) })?;
         }
         Ok(true)
     }
 
-    fn pre_run(&self, _data: &mut Data) -> crate::Result<()> {
-        Ok(())
-    }
-    fn post_run(&self, _data: &mut Data) -> crate::Result<()> {
-        Ok(())
+    fn before_sleep(&self) -> crate::Result<Option<(Readiness, Token)>> {
+        Ok(None)
     }
+    fn before_handle_events(&self, _: EventIterator<'_>) {}
 }
 
 /*