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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
"use strict";
const {
TYPES: { JSTRACER_STATE },
const { JSTracer } = ChromeUtils.importESModule(
{ global: "contextual" }
);
class TracingStateWatcher {
/**
* Start watching for tracing state changes for a given target actor.
*
* @param TargetActor targetActor
* The target actor from which we should observe
* @param Object options
* Dictionary object with following attributes:
* - onAvailable: mandatory function
* This will be called for each resource.
*/
async watch(targetActor, { onAvailable }) {
if (targetActor.targetType == Targets.TYPES.PROCESS) {
return;
}
this.targetActor = targetActor;
this.onAvailable = onAvailable;
this.tracingListener = {
onTracingToggled: this.onTracingToggled.bind(this),
};
JSTracer.addTracingListener(this.tracingListener);
}
/**
* Stop watching for tracing state
*/
destroy() {
if (!this.tracingListener) {
return;
}
JSTracer.removeTracingListener(this.tracingListener);
}
/**
* Be notified by the underlying JavaScriptTracer class
* in case it stops by itself, instead of being stopped when the Actor's stopTracing
* method is called by the user.
*
* @param {Boolean} enabled
* True if the tracer starts tracing, false it it stops.
* @param {String} reason
* Optional string to justify why the tracer stopped.
*/
onTracingToggled(enabled, reason) {
const tracerActor = this.targetActor.getTargetScopedActor("tracer");
const logMethod = tracerActor?.getLogMethod();
// JavascriptTracer only supports recording once in the same process/thread.
// If we open another DevTools, on the same process, we would receive notification
// about a JavascriptTracer controlled by another toolbox's tracer actor.
// Ignore them as our current tracer actor didn't start tracing.
if (!logMethod) {
return;
}
this.onAvailable([
{
resourceType: JSTRACER_STATE,
enabled,
logMethod,
profile:
logMethod == LOG_METHODS.PROFILER && !enabled
? tracerActor.getProfile()
: undefined,
timeStamp: ChromeUtils.dateNow(),
reason,
},
]);
}
}
module.exports = TracingStateWatcher;