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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@ -2,88 +2,19 @@
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
use crossbeam_channel::{select, Receiver, Sender};
use crossbeam_channel::{select, Receiver};
use devtools_traits::DevtoolScriptControlMsg;
use crate::dom::abstractworker::WorkerScriptMsg;
use crate::dom::bindings::conversions::DerivedFrom;
use crate::dom::bindings::reflector::DomObject;
use crate::dom::dedicatedworkerglobalscope::{AutoWorkerReset, DedicatedWorkerScriptMsg};
use crate::dom::dedicatedworkerglobalscope::AutoWorkerReset;
use crate::dom::globalscope::GlobalScope;
use crate::dom::worker::TrustedWorkerAddress;
use crate::dom::workerglobalscope::WorkerGlobalScope;
use crate::realms::enter_realm;
use crate::script_runtime::{CanGc, CommonScriptMsg, ScriptChan, ScriptPort};
use crate::script_runtime::CanGc;
use crate::task_queue::{QueuedTaskConversion, TaskQueue};
/// A ScriptChan that can be cloned freely and will silently send a TrustedWorkerAddress with
/// common event loop messages. While this SendableWorkerScriptChan is alive, the associated
/// Worker object will remain alive.
#[derive(Clone, JSTraceable)]
pub struct SendableWorkerScriptChan {
#[no_trace]
pub sender: Sender<DedicatedWorkerScriptMsg>,
pub worker: TrustedWorkerAddress,
}
impl ScriptChan for SendableWorkerScriptChan {
fn send(&self, msg: CommonScriptMsg) -> Result<(), ()> {
let msg = DedicatedWorkerScriptMsg::CommonWorker(
self.worker.clone(),
WorkerScriptMsg::Common(msg),
);
self.sender.send(msg).map_err(|_| ())
}
fn as_boxed(&self) -> Box<dyn ScriptChan> {
Box::new(SendableWorkerScriptChan {
sender: self.sender.clone(),
worker: self.worker.clone(),
})
}
}
/// A ScriptChan that can be cloned freely and will silently send a TrustedWorkerAddress with
/// worker event loop messages. While this SendableWorkerScriptChan is alive, the associated
/// Worker object will remain alive.
#[derive(Clone, JSTraceable)]
pub struct WorkerThreadWorkerChan {
#[no_trace]
pub sender: Sender<DedicatedWorkerScriptMsg>,
pub worker: TrustedWorkerAddress,
}
impl ScriptChan for WorkerThreadWorkerChan {
fn send(&self, msg: CommonScriptMsg) -> Result<(), ()> {
let msg = DedicatedWorkerScriptMsg::CommonWorker(
self.worker.clone(),
WorkerScriptMsg::Common(msg),
);
self.sender.send(msg).map_err(|_| ())
}
fn as_boxed(&self) -> Box<dyn ScriptChan> {
Box::new(WorkerThreadWorkerChan {
sender: self.sender.clone(),
worker: self.worker.clone(),
})
}
}
impl ScriptPort for Receiver<DedicatedWorkerScriptMsg> {
fn recv(&self) -> Result<CommonScriptMsg, ()> {
let common_msg = match self.recv() {
Ok(DedicatedWorkerScriptMsg::CommonWorker(_worker, common_msg)) => common_msg,
Err(_) => return Err(()),
Ok(DedicatedWorkerScriptMsg::WakeUp) => panic!("unexpected worker event message!"),
};
match common_msg {
WorkerScriptMsg::Common(script_msg) => Ok(script_msg),
WorkerScriptMsg::DOMMessage { .. } => panic!("unexpected worker event message!"),
}
}
}
pub trait WorkerEventLoopMethods {
type WorkerMsg: QueuedTaskConversion + Send;
type ControlMsg;