TimelineJS/source/js/Core/VMM.LoadLib.js

/*	* LoadLib Based on LazyLoad by Ryan Grove
	* https://github.com/rgrove/lazyload/ 
	* Copyright (c) 2011 Ryan Grove <ryan@wonko.com>
	* All rights reserved.

	* Permission is hereby granted, free of charge, to any person obtaining a copy of
	* this software and associated documentation files (the 'Software'), to deal in
	* the Software without restriction, including without limitation the rights to
	* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
	* the Software, and to permit persons to whom the Software is furnished to do so,
	* subject to the following conditions:

	* The above copyright notice and this permission notice shall be included in all
	* copies or substantial portions of the Software.

================================================== */
window.loadedJS = [];


if(typeof VMM != 'undefined' && typeof VMM.LoadLib == 'undefined') {
	//VMM.LoadLib.js('http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js', onJQueryLoaded);
	//VMM.LoadLib.css('http://someurl.css', onCSSLoaded);
	
	
	
	VMM.LoadLib = (function (doc) {
		var env,
		head,
		pending = {},
		pollCount = 0,
		queue = {css: [], js: []},
		styleSheets = doc.styleSheets;
	
		var loaded_Array = [];
	
		function isLoaded(url) {
			var has_been_loaded = false;
			for(var i=0; i<loaded_Array.length; i++) {
				if (loaded_Array[i] == url) {
					has_been_loaded = true;
				}
			}
			if (!has_been_loaded) {
				loaded_Array.push(url);
			}
			return has_been_loaded;
		}

		function createNode(name, attrs) {
			var node = doc.createElement(name), attr;

			for (attr in attrs) {
				if (attrs.hasOwnProperty(attr)) {
					node.setAttribute(attr, attrs[attr]);
				}
			}

			return node;
		}

	  function finish(type) {
	    var p = pending[type],
	        callback,
	        urls;

	    if (p) {
	      callback = p.callback;
	      urls     = p.urls;
	      urls.shift();
	      pollCount = 0;
	      if (!urls.length) {
	        callback && callback.call(p.context, p.obj);
	        pending[type] = null;
	        queue[type].length && load(type);
	      }
	    }
	  }

	  function getEnv() {
	    var ua = navigator.userAgent;

	    env = {

	      async: doc.createElement('script').async === true
	    };

	    (env.webkit = /AppleWebKit\//.test(ua))
	      || (env.ie = /MSIE/.test(ua))
	      || (env.opera = /Opera/.test(ua))
	      || (env.gecko = /Gecko\//.test(ua))
	      || (env.unknown = true);
	  }

	  function load(type, urls, callback, obj, context) {
	    var _finish = function () { finish(type); },
	        isCSS   = type === 'css',
	        nodes   = [],
	        i, len, node, p, pendingUrls, url;

	    env || getEnv();

	    if (urls) {

	      urls = typeof urls === 'string' ? [urls] : urls.concat();

	      if (isCSS || env.async || env.gecko || env.opera) {

	        queue[type].push({
	          urls    : urls,
	          callback: callback,
	          obj     : obj,
	          context : context
	        });
	      } else {
	        for (i = 0, len = urls.length; i < len; ++i) {
	          queue[type].push({
	            urls    : [urls[i]],
	            callback: i === len - 1 ? callback : null,
	            obj     : obj,
	            context : context
	          });
	        }
	      }
	    }

	    if (pending[type] || !(p = pending[type] = queue[type].shift())) {
	      return;
	    }

	    head || (head = doc.head || doc.getElementsByTagName('head')[0]);
	    pendingUrls = p.urls;

	    for (i = 0, len = pendingUrls.length; i < len; ++i) {
	      url = pendingUrls[i];

	      if (isCSS) {
	          node = env.gecko ? createNode('style') : createNode('link', {
	            href: url,
	            rel : 'stylesheet'
	          });
	      } else {
	        node = createNode('script', {src: url});
	        node.async = false;
	      }

	      node.className = 'lazyload';
	      node.setAttribute('charset', 'utf-8');

	      if (env.ie && !isCSS) {
	        node.onreadystatechange = function () {
	          if (/loaded|complete/.test(node.readyState)) {
	            node.onreadystatechange = null;
	            _finish();
	          }
	        };
	      } else if (isCSS && (env.gecko || env.webkit)) {
	        if (env.webkit) {
	          p.urls[i] = node.href; 
	          pollWebKit();
	        } else {
	          node.innerHTML = '@import "' + url + '";';
	          pollGecko(node);
	        }
	      } else {
	        node.onload = node.onerror = _finish;
	      }

	      nodes.push(node);
	    }

	    for (i = 0, len = nodes.length; i < len; ++i) {
	      head.appendChild(nodes[i]);
	    }
	  }

	  function pollGecko(node) {
	    var hasRules;

	    try {

	      hasRules = !!node.sheet.cssRules;
	    } catch (ex) {
	      pollCount += 1;

	      if (pollCount < 200) {
	        setTimeout(function () { pollGecko(node); }, 50);
	      } else {

	        hasRules && finish('css');
	      }

	      return;
	    }

	    finish('css');
	  }

	  function pollWebKit() {
	    var css = pending.css, i;

	    if (css) {
	      i = styleSheets.length;

	      while (--i >= 0) {
	        if (styleSheets[i].href === css.urls[0]) {
	          finish('css');
	          break;
	        }
	      }

	      pollCount += 1;

	      if (css) {
	        if (pollCount < 200) {
	          setTimeout(pollWebKit, 50);
	        } else {

	          finish('css');
	        }
	      }
	    }
	  }

	  return {

		css: function (urls, callback, obj, context) {
			if (isLoaded(urls)) {
				return callback;
			} else {
				load('css', urls, callback, obj, context);
			}
		},

		js: function (urls, callback, obj, context) {
			if (isLoaded(urls)) {
				return callback;
			} else {
				load('js', urls, callback, obj, context);
			}
		}

	  };
	})(this.document);
}