chrome/third_party/chromevox/closure/closure_preinit.js

   1 // Copyright 2010 Google Inc.
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //      http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 /**
  16  * @fileoverview Code to execute before Closure's base.js.
  17  *
  18  * @author dmazzoni@google.com (Dominic Mazzoni)
  19  */
  20
  21 /**
  22  * Tell Closure to load JavaScript code from the extension root directory.
  23  * @type {boolean}
  24  */
  25 window.CLOSURE_BASE_PATH = chrome.extension.getURL('/closure/');
  26
  27 /**
  28  * Tell Closure not to load deps.js; it's included by manifest.json already.
  29  * @type {boolean}
  30  */
  31 window.CLOSURE_NO_DEPS = true;
  32
  33 /**
  34  * Array of urls that should be included next, in order.
  35  * @type {Array}
  36  * @private
  37  */
  38 window.queue_ = [];
  39
  40 /**
  41  * Custom function for importing ChromeVox scripts.
  42  * @param {string} src The JS file to import.
  43  * @return {boolean} Whether the script was imported.
  44  */
  45 window.CLOSURE_IMPORT_SCRIPT = function(src) {
  46   // Only run our version of the import script
  47   // when trying to inject ChromeVox scripts.
  48   if (src.indexOf('chrome-extension://') == 0) {
  49     if (!goog.inHtmlDocument_() ||
  50         goog.dependencies_.written[src]) {
  51       return false;
  52     }
  53     goog.dependencies_.written[src] = true;
  54     function loadNextScript() {
  55       if (goog.global.queue_.length == 0)
  56         return;
  57
  58       var src = goog.global.queue_[0];
  59
  60       if (window.CLOSURE_USE_EXT_MESSAGES) {
  61         var relativeSrc = src.substr(src.indexOf('closure/..') + 11);
  62         chrome.extension.sendMessage(
  63             {'srcFile': relativeSrc},
  64             function(response) {
  65               try {
  66                 eval(response['code']);
  67               } catch (e) {
  68                 console.error('Script error: ' + e + ' in ' + src);
  69               }
  70               goog.global.queue_ = goog.global.queue_.slice(1);
  71               loadNextScript();
  72             });
  73         return;
  74       }
  75       window.console.log('Using XHR');
  76
  77       // Load the script by fetching its source and running 'eval' on it
  78       // directly, with a magic comment that makes Chrome treat it like it
  79       // loaded normally. Wait until it's fetched before loading the
  80       // next script.
  81       var xhr = new XMLHttpRequest();
  82       var url = src + '?' + new Date().getTime();
  83       xhr.onreadystatechange = function() {
  84         if (xhr.readyState == 4) {
  85           var scriptText = xhr.responseText;
  86           // Add a magic comment to the bottom of the file so that
  87           // Chrome knows the name of the script in the JavaScript debugger.
  88           scriptText += '\n//# sourceURL=' + src + '\n';
  89           eval(scriptText);
  90           goog.global.queue_ = goog.global.queue_.slice(1);
  91           loadNextScript();
  92         }
  93       };
  94       xhr.open('GET', url, false);
  95       xhr.send(null);
  96     }
  97     goog.global.queue_.push(src);
  98     if (goog.global.queue_.length == 1) {
  99       loadNextScript();
 100     }
 101     return true;
 102   } else {
 103     return goog.writeScriptTag_(src);
 104   }
 105 };