Differential D4581 Diff 9612 externals/javelin/src/lib/Resource.js

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externals/javelin/src/lib/Resource.js

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				/**
				* @provides javelin-resource
				* @requires javelin-magical-init
				* javelin-stratcom
				* javelin-util
				* javelin-uri
				*
				* @javelin
				*/

				JX.install('Resource', {

				statics: {

				_loading: {},
				_loaded: {},
				_links: [],
				_callbacks: [],

				/**
				* Loads one or many static resources (JavaScript or CSS) and executes a
				* callback once these resources have finished loading.
				*
				* @param string\|array static resource or list of resources to be loaded
				* @param function callback when resources have finished loading
				*/
				load: function(list, callback) {
				var resources = {},
				uri, resource, path, type;

				list = JX.$AX(list);

				// In the event there are no resources to wait on, call the callback and
				// exit. NOTE: it's better to do this check outside this function and not
				// call through JX.Resource, but it's not always easy/possible to do so
				if (!list.length) {
				setTimeout(callback, 0);
				return;
				}

				for (var ii = 0; ii < list.length; ii++) {
				uri = new JX.URI(list[ii]);
				resource = uri.toString();
				path = uri.getPath();
				resources[resource] = true;

				if (JX.Resource._loaded[resource]) {
				setTimeout(JX.bind(JX.Resource, JX.Resource._complete, resource), 0);
				} else if (!JX.Resource._loading[resource]) {
				JX.Resource._loading[resource] = true;
				if (path.indexOf('.css') == path.length - 4) {
				JX.Resource._loadCSS(resource);
				} else {
				JX.Resource._loadJS(resource);
				}
				}
				}

				JX.Resource._callbacks.push({
				resources: resources,
				callback: callback
				});
				},

				_loadJS: function(uri) {
				var script = document.createElement('script');
				var load_callback = function() {
				JX.Resource._complete(uri);
				};
				var error_callback = function() {
				JX.$E('Resource: JS file download failure: ' + uri);
				};

				JX.copy(script, {
				type: 'text/javascript',
				src: uri
				});

				script.onload = load_callback;
				script.onerror = error_callback;
				script.onreadystatechange = function() {
				var state = this.readyState;
				if (state == 'complete' \|\| state == 'loaded') {
				load_callback();
				}
				};
				document.getElementsByTagName('head')[0].appendChild(script);
				},

				_loadCSS: function(uri) {
				var link = JX.copy(document.createElement('link'), {
				type: 'text/css',
				rel: 'stylesheet',
				href: uri,
				'data-href': uri // don't trust href
				});
				document.getElementsByTagName('head')[0].appendChild(link);

				JX.Resource._links.push(link);
				if (!JX.Resource._timer) {
				JX.Resource._timer = setInterval(JX.Resource._poll, 20);
				}
				},

				_poll: function() {
				var sheets = document.styleSheets,
				ii = sheets.length,
				links = JX.Resource._links;

				// Cross Origin CSS loading
				// http://yearofmoo.com/2011/03/cross-browser-stylesheet-preloading/
				while (ii--) {
				var link = sheets[ii],
				owner = link.ownerNode \|\| link.owningElement,
				jj = links.length;
				if (owner) {
				while (jj--) {
				if (owner == links[jj]) {
				JX.Resource._complete(links[jj]['data-href']);
				links.splice(jj, 1);
				}
				}
				}
				}

				if (!links.length) {
				clearInterval(JX.Resource._timer);
				JX.Resource._timer = null;
				}
				},

				_complete: function(uri) {
				var list = JX.Resource._callbacks,
				current, ii;

				delete JX.Resource._loading[uri];
				JX.Resource._loaded[uri] = true;

				for (ii = 0; ii < list.length; ii++) {
				current = list[ii];
				delete current.resources[uri];
				if (!JX.Resource._hasResources(current.resources)) {
				current.callback();
				list.splice(ii--, 1);
				}
				}
				},

				_hasResources: function(resources) {
				for (var hasResources in resources) {
				return true;
				}
				return false;
				}

				},

				initialize: function() {
				var list = JX.$A(document.getElementsByTagName('link')),
				ii = list.length,
				node;
				while ((node = list[--ii])) {
				if (node.type == 'text/css' && node.href) {
				JX.Resource._loaded[(new JX.URI(node.href)).toString()] = true;
				}
				}

				list = JX.$A(document.getElementsByTagName('script'));
				ii = list.length;
				while ((node = list[--ii])) {
				if (node.type == 'text/javascript' && node.src) {
				JX.Resource._loaded[(new JX.URI(node.src)).toString()] = true;
				}
				}
				}

				});