Source code
Revision control
Copy as Markdown
Other Tools
/* 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";
/**
* A Descriptor represents a debuggable context. It can be a browser tab, a tab on
* a remote device, like a tab on Firefox for Android. But it can also be an add-on,
* as well as firefox parent process, or just one of its content process.
* It can be very similar to a Target. The key difference is the lifecycle of these two classes.
* The descriptor is meant to be always alive and meaningful/usable until the end of the RDP connection.
* Typically a Tab Descriptor will describe the tab and not the one document currently loaded in this tab,
* while the Target, will describe this one document and a new Target may be created on each navigation.
*/
function DescriptorMixin(parentClass) {
class Descriptor extends parentClass {
constructor(client, targetFront, parentFront) {
super(client, targetFront, parentFront);
this._client = client;
// Pass a true value in order to distinguish this event reception
// from any manual destroy caused by the frontend
this.on(
"descriptor-destroyed",
this.destroy.bind(this, { isServerDestroyEvent: true })
);
}
get client() {
return this._client;
}
async destroy({ isServerDestroyEvent } = {}) {
if (this.isDestroyed()) {
return;
}
// This workaround is mostly done for Workers, as WorkerDescriptor
// extends the Target class, which causes some issue down the road:
// In Target.destroy, we call WorkerDescriptorActor.detach *before* calling super.destroy(),
// and so hold on before calling Front.destroy() which would reject all pending requests, including detach().
// When calling detach, the server will emit "descriptor-destroyed", which will call Target.destroy again,
// but will still be blocked on detach resolution and won't call Front.destroy, and won't reject pending requests either.
//
// So call Front.baseFrontClassDestroyed manually from here, so that we ensure rejecting the pending detach request
// and unblock Target.destroy resolution.
//
// Here is the inheritance chain for WorkerDescriptor:
// WorkerDescriptor -> Descriptor (from descriptor-mixin.js) -> Target (from target-mixin.js) -> Front (protocol.js) -> Pool (protocol.js) -> EventEmitter
if (isServerDestroyEvent) {
this.baseFrontClassDestroy();
}
await super.destroy();
}
}
return Descriptor;
}
exports.DescriptorMixin = DescriptorMixin;