script: Use enums for event loop senders and receivers (#34896)

Previously, senders and receivers to different kinds of event loops (the
main `ScriptThread`, different types of workers) used a rust `trait`
mechanism to implement dynamic behavior. This led to having many unused
implementations of this `trait`. This change moves to using an `enum`
based approach for these senders and receivers and removes all of the
dead code.

In addition, to allowing for use of rust's dead code detection, it
simplifies the code a great deal. All of these generic senders and
receivers are moved to the `messaging.rs` file and given proper
documentation.

Finally, empty an `JSTraceable` implementation is made for all
crossbeam `Sender<...>`s to avoid having to manually skip them everytime
they are included in structs. The pre-existing empty `MallocSizeOf`
implementation is used more thoroughly.

Other unecessary wrappers around these senders and receivers are removed
as well.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>
This commit is contained in:
Martin Robinson 2025-01-08 22:33:29 +01:00 committed by GitHub
parent 82ac8d41d0
commit 77bc7f415d
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18 changed files with 217 additions and 325 deletions

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@ -37,6 +37,7 @@ use std::hash::{BuildHasher, Hash};
use std::mem;
use std::ops::{Deref, DerefMut};
use crossbeam_channel::Sender;
use indexmap::IndexMap;
/// A trait to allow tracing (only) DOM objects.
pub use js::gc::Traceable as JSTraceable;
@ -107,6 +108,10 @@ unsafe impl<T: JSTraceable> CustomTraceable for OnceCell<T> {
}
}
unsafe impl<T> CustomTraceable for Sender<T> {
unsafe fn trace(&self, _: *mut JSTracer) {}
}
/// Wrapper type for nop traceble
///
/// SAFETY: Inner type must not impl JSTraceable