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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";
// The prefix used for RDM messages in content.
// see: devtools/client/responsive/browser/content.js
const MESSAGE_PREFIX = "ResponsiveMode:";
const REQUEST_DONE_SUFFIX = ":Done";
/**
* Registers a message `listener` that is called every time messages of
* specified `message` is emitted on the given message manager.
* @param {nsIMessageListenerManager} mm
* The Message Manager
* @param {String} message
* The message. It will be prefixed with the constant `MESSAGE_PREFIX`
* @param {Function} listener
* The listener function that processes the message.
*/
function on(mm, message, listener) {
mm.addMessageListener(MESSAGE_PREFIX + message, listener);
}
exports.on = on;
/**
* Removes a message `listener` for the specified `message` on the given
* message manager.
* @param {nsIMessageListenerManager} mm
* The Message Manager
* @param {String} message
* The message. It will be prefixed with the constant `MESSAGE_PREFIX`
* @param {Function} listener
* The listener function that processes the message.
*/
function off(mm, message, listener) {
mm.removeMessageListener(MESSAGE_PREFIX + message, listener);
}
exports.off = off;
/**
* Resolves a promise the next time the specified `message` is sent over the
* given message manager.
* @param {nsIMessageListenerManager} mm
* The Message Manager
* @param {String} message
* The message. It will be prefixed with the constant `MESSAGE_PREFIX`
* @returns {Promise}
* A promise that is resolved when the given message is emitted.
*/
function once(mm, message) {
return new Promise(resolve => {
on(mm, message, function onMessage({ data }) {
off(mm, message, onMessage);
resolve(data);
});
});
}
exports.once = once;
/**
* Asynchronously emit a `message` to the listeners of the given message
* manager.
*
* @param {nsIMessageListenerManager} mm
* The Message Manager
* @param {String} message
* The message. It will be prefixed with the constant `MESSAGE_PREFIX`.
* @param {Object} data
* A JSON object containing data to be delivered to the listeners.
*/
function emit(mm, message, data) {
mm.sendAsyncMessage(MESSAGE_PREFIX + message, data);
}
exports.emit = emit;
/**
* Asynchronously send a "request" over the given message manager, and returns
* a promise that is resolved when the request is complete.
*
* @param {nsIMessageListenerManager} mm
* The Message Manager
* @param {String} message
* The message. It will be prefixed with the constant `MESSAGE_PREFIX`, and
* also suffixed with `REQUEST_DONE_SUFFIX` for the reply.
* @param {Object} data
* A JSON object containing data to be delivered to the listeners.
* @returns {Promise}
* A promise that is resolved when the request is done.
*/
function request(mm, message, data) {
const done = once(mm, message + REQUEST_DONE_SUFFIX);
emit(mm, message, data);
return done;
}
exports.request = request;