gecko-dev/devtools/server/content-globals.js

/* 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 http://mozilla.org/MPL/2.0/. */
"use strict";

const { Ci } = require("chrome");
const Services = require("Services");

var globalsCache = {};

exports.addContentGlobal = function(options) {
  if (!options || !options.global || !options['inner-window-id']) {
    throw Error('Invalid arguments');
  }
  let cache = getGlobalCache(options['inner-window-id']);
  cache.push(options.global);
  return undefined;
}

exports.getContentGlobals = function(options) {
  if (!options || !options['inner-window-id']) {
    throw Error('Invalid arguments');
  }
  return Array.slice(globalsCache[options['inner-window-id']] || []);
}

exports.removeContentGlobal = function(options) {
  if (!options || !options.global || !options['inner-window-id']) {
    throw Error('Invalid arguments');
  }
  let cache = getGlobalCache(options['inner-window-id']);
  let index = cache.indexOf(options.global);
  cache.splice(index, 1);
  return undefined;
}

function getGlobalCache(aInnerWindowID) {
  return globalsCache[aInnerWindowID] = globalsCache[aInnerWindowID] || [];
}

// when the window is destroyed, eliminate the associated globals cache
if (!isWorker) {
  Services.obs.addObserver(function observer(subject, topic, data) {
    let id = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
    delete globalsCache[id];
  }, 'inner-window-destroyed', false);
}