third_party/polymer/components-chromium/core-shared-lib/core-shared-lib-extracted.js

   1
   2 (function() {
   3
   4   Polymer('core-shared-lib',{
   5
   6     notifyEvent: 'core-shared-lib-load',
   7
   8     ready: function() {
   9       if (!this.url && this.defaultUrl) {
  10         this.url = this.defaultUrl;
  11       }
  12     },
  13
  14     urlChanged: function() {
  15       require(this.url, this, this.callbackName);
  16     },
  17
  18     provide: function() {
  19       this.async('notify');
  20     },
  21
  22     notify: function() {
  23       this.fire(this.notifyEvent, arguments);
  24     }
  25
  26   });
  27
  28   var apiMap = {};
  29
  30   function require(url, notifiee, callbackName) {
  31     // make hashable string form url
  32     var name = nameFromUrl(url);
  33     // lookup existing loader instance
  34     var loader = apiMap[name];
  35     // create a loader as needed
  36     if (!loader) {
  37       loader = apiMap[name] = new Loader(name, url, callbackName);
  38     }
  39     loader.requestNotify(notifiee);
  40   }
  41
  42   function nameFromUrl(url) {
  43     return url.replace(/[\:\/\%\?\&\.\=\-\,]/g, '_') + '_api';
  44   }
  45
  46   var Loader = function(name, url, callbackName) {
  47     this.instances = [];
  48     this.callbackName = callbackName;
  49     if (this.callbackName) {
  50       window[this.callbackName] = this.success.bind(this);
  51     } else {
  52       if (url.indexOf(this.callbackMacro) >= 0) {
  53         this.callbackName = name + '_loaded';
  54         window[this.callbackName] = this.success.bind(this);
  55         url = url.replace(this.callbackMacro, this.callbackName);
  56       } else {
  57         // TODO(sjmiles): we should probably fallback to listening to script.load
  58         throw 'core-shared-api: a %%callback%% parameter is required in the API url';
  59       }
  60     }
  61     //
  62     this.addScript(url);
  63   };
  64
  65   Loader.prototype = {
  66
  67     callbackMacro: '%%callback%%',
  68     loaded: false,
  69
  70     addScript: function(src) {
  71       var script = document.createElement('script');
  72       script.src = src;
  73       script.onerror = this.error.bind(this);
  74       var s = document.querySelector('script');
  75       s.parentNode.insertBefore(script, s);
  76       this.script = script;
  77     },
  78
  79     removeScript: function() {
  80       if (this.script.parentNode) {
  81         this.script.parentNode.removeChild(this.script);
  82       }
  83       this.script = null;
  84     },
  85
  86     error: function() {
  87       this.cleanup();
  88     },
  89
  90     success: function() {
  91       this.loaded = true;
  92       this.cleanup();
  93       this.result = Array.prototype.slice.call(arguments);
  94       this.instances.forEach(this.provide, this);
  95       this.instances = null;
  96     },
  97
  98     cleanup: function() {
  99       delete window[this.callbackName];
 100     },
 101
 102     provide: function(instance) {
 103       instance.notify(instance, this.result);
 104     },
 105
 106     requestNotify: function(instance) {
 107       if (this.loaded) {
 108         this.provide(instance);
 109       } else {
 110         this.instances.push(instance);
 111       }
 112     }
 113
 114   };
 115
 116 })();