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/* This Source Code Form is subject to the terms of the Mozilla Public
* 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 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::globalscope::GlobalScope;
use crate::dom::worker::TrustedWorkerAddress;
use crate::dom::workerglobalscope::WorkerGlobalScope;
use crate::script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort};
use crate::task_queue::{QueuedTaskConversion, TaskQueue};
use crossbeam_channel::{Receiver, Sender};
use devtools_traits::DevtoolScriptControlMsg;
/// 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 {
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 clone(&self) -> Box<dyn ScriptChan + Send> {
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 {
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 clone(&self) -> Box<dyn ScriptChan + Send> {
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 TimerMsg: Send;
type WorkerMsg: QueuedTaskConversion + Send;
type Event;
fn timer_event_port(&self) -> &Receiver<Self::TimerMsg>;
fn task_queue(&self) -> &TaskQueue<Self::WorkerMsg>;
fn handle_event(&self, event: Self::Event);
fn handle_worker_post_event(&self, worker: &TrustedWorkerAddress) -> Option<AutoWorkerReset>;
fn from_worker_msg(&self, msg: Self::WorkerMsg) -> Self::Event;
fn from_timer_msg(&self, msg: Self::TimerMsg) -> Self::Event;
fn from_devtools_msg(&self, msg: DevtoolScriptControlMsg) -> Self::Event;
}
// https://html.spec.whatwg.org/multipage/#worker-event-loop
pub fn run_worker_event_loop<T, TimerMsg, WorkerMsg, Event>(
worker_scope: &T,
worker: Option<&TrustedWorkerAddress>,
) where
TimerMsg: Send,
WorkerMsg: QueuedTaskConversion + Send,
T: WorkerEventLoopMethods<TimerMsg = TimerMsg, WorkerMsg = WorkerMsg, Event = Event>
+ DerivedFrom<WorkerGlobalScope>
+ DerivedFrom<GlobalScope>
+ DomObject,
{
let scope = worker_scope.upcast::<WorkerGlobalScope>();
let timer_event_port = worker_scope.timer_event_port();
let devtools_port = match scope.from_devtools_sender() {
Some(_) => Some(scope.from_devtools_receiver()),
None => None,
};
let task_queue = worker_scope.task_queue();
let event = select! {
recv(task_queue.select()) -> msg => {
task_queue.take_tasks(msg.unwrap());
worker_scope.from_worker_msg(task_queue.recv().unwrap())
},
recv(timer_event_port) -> msg => worker_scope.from_timer_msg(msg.unwrap()),
recv(devtools_port.unwrap_or(&crossbeam_channel::never())) -> msg =>
worker_scope.from_devtools_msg(msg.unwrap()),
};
let mut sequential = vec![];
sequential.push(event);
// https://html.spec.whatwg.org/multipage/#worker-event-loop
// Once the WorkerGlobalScope's closing flag is set to true,
// the event loop's task queues must discard any further tasks
// that would be added to them
// (tasks already on the queue are unaffected except where otherwise specified).
while !scope.is_closing() {
// Batch all events that are ready.
// The task queue will throttle non-priority tasks if necessary.
match task_queue.try_recv() {
Err(_) => match timer_event_port.try_recv() {
Err(_) => match devtools_port.map(|port| port.try_recv()) {
None => {},
Some(Err(_)) => break,
Some(Ok(ev)) => sequential.push(worker_scope.from_devtools_msg(ev)),
},
Ok(ev) => sequential.push(worker_scope.from_timer_msg(ev)),
},
Ok(ev) => sequential.push(worker_scope.from_worker_msg(ev)),
}
}
// Step 3
for event in sequential {
worker_scope.handle_event(event);
// Step 6
let _ar = match worker {
Some(worker) => worker_scope.handle_worker_post_event(worker),
None => None,
};
worker_scope
.upcast::<GlobalScope>()
.perform_a_microtask_checkpoint();
}
}
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