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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
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
EventEmitter: "resource://gre/modules/EventEmitter.sys.mjs",
NetworkUtils:
"resource://devtools/shared/network-observer/NetworkUtils.sys.mjs",
});
const OBSERVER_TOPIC_DATA_CHANNEL_OPENED = "data-channel-opened";
/**
* The DataChannelListener can be used to listen for
* data-channel-opened notifications emitted for data channels.
* This notification should be monitored in content processes.
* Note that parent process notifications will be emitted for navigation
* requests and therefore should be ignored here.
*
* Example:
* ```
* const listener = new DataChannelListener();
* listener.on("data-channel-opened", DataChannelListener);
* listener.startListening();
*
* const onDataChannelOpened = (eventName, data = {}) => {
* const { channel } = data;
* ...
* };
* ```
*
* @fires cached-resource-sent
* The DataChannelListener emits "data-channel-opened" event with the
* following object as payload:
* - {nsIDataChannel} channel
* The data channel for which the observer notification was emitted.
*/
export class DataChannelListener {
#context;
#listening;
/**
* Create a new DataChannelListener instance.
*
* @param {BrowsingContext} context
* The browsing context to filter the events for.
*/
constructor(context) {
lazy.EventEmitter.decorate(this);
this.#listening = false;
this.#context = context;
}
destroy() {
this.stopListening();
}
observe(subject, topic) {
switch (topic) {
case OBSERVER_TOPIC_DATA_CHANNEL_OPENED: {
if (!(subject instanceof Ci.nsIDataChannel)) {
return;
}
const channel = subject.QueryInterface(Ci.nsIDataChannel);
channel.QueryInterface(Ci.nsIChannel);
if (channel.isDocument) {
// navigation data URIs are handled in the parent process, where we have
// access to the navigation manager.
return;
}
const id = lazy.NetworkUtils.getChannelBrowsingContextID(channel);
const browsingContext = BrowsingContext.get(id);
// Send the event only if the notification comes for the observed
// context.
if (browsingContext === this.#context) {
this.emit("data-channel-opened", {
channel,
});
}
break;
}
}
}
startListening() {
if (this.#listening) {
return;
}
Services.obs.addObserver(this, OBSERVER_TOPIC_DATA_CHANNEL_OPENED);
this.#listening = true;
}
stopListening() {
if (!this.#listening) {
return;
}
Services.obs.removeObserver(this, OBSERVER_TOPIC_DATA_CHANNEL_OPENED);
this.#listening = false;
}
}