Incremental progress toward archive loading in o3d-webgl. Implemented...

samples/o3d-webgl/file_request.js

 /*
  * Copyright 2010, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 169 matching lines @@
 
 /**
  * Set up several of the request fields.
  * @param {string} method "GET" is the only supported method at this time
  * @param {string} uri the location of the file to fetch
  * @param {boolean} async true is the only legal value at this time.
  */
 o3d.FileRequest.prototype.open =
     function(method, uri, async) {
   this.uri = uri;
+  // TODO(petersont): I think there is a race condition here -- calling
+  // code expects that it can still set up the onreadystatechange callback
+  // between open() and send(), but if open() actually initiates the XHR
+  // then the caller may miss the crucial completion callback!
   if (this.isImageUrl_(uri)) {
     this.image_ = new Image();
     var that = this;
     this.image_.onload = function() {
       that.imageLoaded_.call(that);
     }
     this.image_.src = uri;
   } else {
     this.request_.open(method, uri, async);
   }
 };
 
 
 /**
  * Send the request.
  * Unlike XMLHttpRequest the onreadystatechange callback will be called no
  * matter what, with success or failure.
  */
 o3d.FileRequest.prototype.send = function() {
   // This function left blank for compatability with o3djs.io.
 };