extensions/renderer/resources/service_worker_bindings.js

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This function is returned to DidInitializeServiceWorkerContextOnWorkerThread
   6 // then executed, passing in dependencies as function arguments.
   7 //
   8 // |backgroundUrl| is the URL of the extension's background page.
   9 // |wakeEventPage| is a function that wakes up the current extension's event
  10 // page, then runs its callback on completion or failure.
  11 // |logging| is an object equivalent to a subset of base/debug/logging.h, with
  12 // CHECK/DCHECK/etc.
  13 (function(backgroundUrl, wakeEventPage, logging) {
  14   'use strict';
  15   self.chrome = self.chrome || {};
  16   self.chrome.runtime = self.chrome.runtime || {};
  17
  18   // Returns a Promise that resolves to the background page's client, or null
  19   // if there is no background client.
  20   function findBackgroundClient() {
  21     return self.clients.matchAll({
  22       includeUncontrolled: true,
  23       type: 'window'
  24     }).then(function(clients) {
  25       return clients.find(function(client) {
  26         return client.url == backgroundUrl;
  27       });
  28     });
  29   }
  30
  31   // Returns a Promise wrapper around wakeEventPage, that resolves on success,
  32   // or rejects on failure.
  33   function makeWakeEventPagePromise() {
  34     return new Promise(function(resolve, reject) {
  35       wakeEventPage(function(success) {
  36         if (success)
  37           resolve();
  38         else
  39           reject('Failed to start background client "' + backgroundUrl + '"');
  40       });
  41     });
  42   }
  43
  44   // The chrome.runtime.getBackgroundClient function is documented in
  45   // runtime.json. It returns a Promise that resolves to the background page's
  46   // client, or is rejected if there is no background client or if the
  47   // background client failed to wake.
  48   self.chrome.runtime.getBackgroundClient = function() {
  49     return findBackgroundClient().then(function(client) {
  50       if (client) {
  51         // Background client is already awake, or it was persistent.
  52         return client;
  53       }
  54
  55       // Event page needs to be woken.
  56       return makeWakeEventPagePromise().then(function() {
  57         return findBackgroundClient();
  58       }).then(function(client) {
  59         if (!client) {
  60           return Promise.reject(
  61             'Background client "' + backgroundUrl + '" not found');
  62         }
  63         return client;
  64       });
  65     });
  66   };
  67 });