(function() {
+
+/**
+ * Provides a mechanism to fetch remote resources and
+ * insert them into a document.
+ * @module yui
+ * @submodule get
+ */
+
+var ua = Y.UA,
+ L = Y.Lang,
+ // PREFIX = Y.guid(),
+ TYPE_JS = "text/javascript",
+ TYPE_CSS = "text/css",
+ STYLESHEET = "stylesheet";
+
+/**
+ * Fetches and inserts one or more script or link nodes into the document
+ * @class Get
+ * @static
+ */
+Y.Get = function() {
+
+ /**
+ * hash of queues to manage multiple requests
+ * @property queues
+ * @private
+ */
+ var queues={},
+
+ /**
+ * queue index used to generate transaction ids
+ * @property qidx
+ * @type int
+ * @private
+ */
+ qidx=0,
+
+ /**
+ * interal property used to prevent multiple simultaneous purge
+ * processes
+ * @property purging
+ * @type boolean
+ * @private
+ */
+ purging=false,
+
+
+ /**
+ * Generates an HTML element, this is not appended to a document
+ * @method _node
+ * @param type {string} the type of element
+ * @param attr {string} the attributes
+ * @param win {Window} optional window to create the element in
+ * @return {HTMLElement} the generated node
+ * @private
+ */
+ _node = function(type, attr, win) {
+ var w = win || Y.config.win, d=w.document, n=d.createElement(type),
+ i;
+
+ for (i in attr) {
+ if (attr[i] && attr.hasOwnProperty(i)) {
+ n.setAttribute(i, attr[i]);
+ }
+ }
+
+ return n;
+ },
+
+ /**
+ * Generates a link node
+ * @method _linkNode
+ * @param url {string} the url for the css file
+ * @param win {Window} optional window to create the node in
+ * @param attributes optional attributes collection to apply to the new node
+ * @return {HTMLElement} the generated node
+ * @private
+ */
+ _linkNode = function(url, win, attributes) {
+ var o = {
+ id: Y.guid(),
+ type: TYPE_CSS,
+ rel: STYLESHEET,
+ href: url
+ };
+ if (attributes) {
+ Y.mix(o, attributes);
+ }
+ return _node("link", o, win);
+ },
+
+ /**
+ * Generates a script node
+ * @method _scriptNode
+ * @param url {string} the url for the script file
+ * @param win {Window} optional window to create the node in
+ * @param attributes optional attributes collection to apply to the new node
+ * @return {HTMLElement} the generated node
+ * @private
+ */
+ _scriptNode = function(url, win, attributes) {
+ var o = {
+ id: Y.guid(),
+ type: TYPE_JS,
+ src: url
+ };
+
+ if (attributes) {
+ Y.mix(o, attributes);
+ }
+
+ return _node("script", o, win);
+ },
+
+ /**
+ * Removes the nodes for the specified queue
+ * @method _purge
+ * @private
+ */
+ _purge = function(tId) {
+ var q=queues[tId], n, l, d, h, s, i, node, attr;
+ if (q) {
+ n = q.nodes;
+ l = n.length;
+ d = q.win.document;
+ h = d.getElementsByTagName("head")[0];
+
+ if (q.insertBefore) {
+ s = _get(q.insertBefore, tId);
+ if (s) {
+ h = s.parentNode;
+ }
+ }
+
+ for (i=0; i<l; i=i+1) {
+ node = n[i];
+ if (node.clearAttributes) {
+ node.clearAttributes();
+ } else {
+ // This is a hostile delete
+ // operation attempting to improve
+ // memory performance. As such, the
+ // hasOwnProperty check is intentionally
+ // ommitted.
+ for (attr in node) {
+ delete node[attr];
+ }
+ }
+
+ h.removeChild(node);
+ }
+ }
+ q.nodes = [];
+ },
+
+ /**
+ * Returns the data payload for callback functions
+ * @method _returnData
+ * @private
+ */
+ _returnData = function(q, msg, result) {
+ return {
+ tId: q.tId,
+ win: q.win,
+ data: q.data,
+ nodes: q.nodes,
+ msg: msg,
+ statusText: result,
+ purge: function() {
+ _purge(this.tId);
+ }
+ };
+ },
+
+ /**
+ * The transaction is finished
+ * @method _end
+ * @param id {string} the id of the request
+ * @private
+ */
+ _end = function(id, msg, result) {
+ var q = queues[id], sc;
+ if (q && q.onEnd) {
+ sc = q.context || q;
+ q.onEnd.call(sc, _returnData(q, msg, result));
+ }
+ },
+
+ /*
+ * The request failed, execute fail handler with whatever
+ * was accomplished. There isn't a failure case at the
+ * moment unless you count aborted transactions
+ * @method _fail
+ * @param id {string} the id of the request
+ * @private
+ */
+ _fail = function(id, msg) {
+
+ Y.log("get failure: " + msg, "warn", "get");
+
+ var q = queues[id], sc;
+ if (q.timer) {
+ // q.timer.cancel();
+ clearTimeout(q.timer);
+ }
+
+ // execute failure callback
+ if (q.onFailure) {
+ sc = q.context || q;
+ q.onFailure.call(sc, _returnData(q, msg));
+ }
+
+ _end(id, msg, 'failure');
+ },
+
+ _get = function(nId, tId) {
+ var q = queues[tId],
+ n = (L.isString(nId)) ? q.win.document.getElementById(nId) : nId;
+ if (!n) {
+ _fail(tId, "target node not found: " + nId);
+ }
+
+ return n;
+ },
+
+ /**
+ * The request is complete, so executing the requester's callback
+ * @method _finish
+ * @param id {string} the id of the request
+ * @private
+ */
+ _finish = function(id) {
+ Y.log("Finishing transaction " + id, "info", "get");
+ var q = queues[id], msg, sc;
+ if (q.timer) {
+ // q.timer.cancel();
+ clearTimeout(q.timer);
+ }
+ q.finished = true;
+
+ if (q.aborted) {
+ msg = "transaction " + id + " was aborted";
+ _fail(id, msg);
+ return;
+ }
+
+ // execute success callback
+ if (q.onSuccess) {
+ sc = q.context || q;
+ q.onSuccess.call(sc, _returnData(q));
+ }
+
+ _end(id, msg, 'OK');
+ },
+
+ /**
+ * Timeout detected
+ * @method _timeout
+ * @param id {string} the id of the request
+ * @private
+ */
+ _timeout = function(id) {
+ Y.log("Timeout " + id, "info", "get");
+ var q = queues[id], sc;
+ if (q.onTimeout) {
+ sc = q.context || q;
+ q.onTimeout.call(sc, _returnData(q));
+ }
+
+ _end(id, 'timeout', 'timeout');
+ },
+
+
+ /**
+ * Loads the next item for a given request
+ * @method _next
+ * @param id {string} the id of the request
+ * @param loaded {string} the url that was just loaded, if any
+ * @private
+ */
+ _next = function(id, loaded) {
+
+ Y.log("_next: " + id + ", loaded: " + (loaded || "nothing"), "info", "get");
+
+ var q = queues[id], msg, w, d, h, n, url, s;
+
+ if (q.timer) {
+ // Y.log('cancel timer');
+ // q.timer.cancel();
+ clearTimeout(q.timer);
+ }
+
+ if (q.aborted) {
+ msg = "transaction " + id + " was aborted";
+ _fail(id, msg);
+ return;
+ }
+
+ if (loaded) {
+ q.url.shift();
+ if (q.varName) {
+ q.varName.shift();
+ }
+ } else {
+ // This is the first pass: make sure the url is an array
+ q.url = (L.isString(q.url)) ? [q.url] : q.url;
+ if (q.varName) {
+ q.varName = (L.isString(q.varName)) ? [q.varName] : q.varName;
+ }
+ }
+
+ w = q.win;
+ d = w.document;
+ h = d.getElementsByTagName("head")[0];
+
+ if (q.url.length === 0) {
+ _finish(id);
+ return;
+ }
+
+ url = q.url[0];
+
+ // if the url is undefined, this is probably a trailing comma problem in IE
+ if (!url) {
+ q.url.shift();
+ Y.log('skipping empty url');
+ return _next(id);
+ }
+
+ Y.log("attempting to load " + url, "info", "get");
+
+ if (q.timeout) {
+ // Y.log('create timer');
+ // q.timer = L.later(q.timeout, q, _timeout, id);
+ q.timer = setTimeout(function() {
+ _timeout(id);
+ }, q.timeout);
+ }
+
+ if (q.type === "script") {
+ n = _scriptNode(url, w, q.attributes);
+ } else {
+ n = _linkNode(url, w, q.attributes);
+ }
+
+ // track this node's load progress
+ _track(q.type, n, id, url, w, q.url.length);
+
+ // add the node to the queue so we can return it to the user supplied callback
+ q.nodes.push(n);
+
+ // add it to the head or insert it before 'insertBefore'
+ if (q.insertBefore) {
+ s = _get(q.insertBefore, id);
+ if (s) {
+ s.parentNode.insertBefore(n, s);
+ }
+ } else {
+ h.appendChild(n);
+ }
+
+ Y.log("Appending node: " + url, "info", "get");
+
+ // FireFox does not support the onload event for link nodes, so there is
+ // no way to make the css requests synchronous. This means that the css
+ // rules in multiple files could be applied out of order in this browser
+ // if a later request returns before an earlier one. Safari too.
+ if ((ua.webkit || ua.gecko) && q.type === "css") {
+ _next(id, url);
+ }
+ },
+
+ /**
+ * Removes processed queues and corresponding nodes
+ * @method _autoPurge
+ * @private
+ */
+ _autoPurge = function() {
+
+ if (purging) {
+ return;
+ }
+
+ purging = true;
+
+ var i, q;
+
+ for (i in queues) {
+ if (queues.hasOwnProperty(i)) {
+ q = queues[i];
+ if (q.autopurge && q.finished) {
+ _purge(q.tId);
+ delete queues[i];
+ }
+ }
+ }
+
+ purging = false;
+ },
+
+ /**
+ * Saves the state for the request and begins loading
+ * the requested urls
+ * @method queue
+ * @param type {string} the type of node to insert
+ * @param url {string} the url to load
+ * @param opts the hash of options for this request
+ * @private
+ */
+ _queue = function(type, url, opts) {
+
+ opts = opts || {};
+
+ var id = "q" + (qidx++), q,
+ thresh = opts.purgethreshold || Y.Get.PURGE_THRESH;
+
+ if (qidx % thresh === 0) {
+ _autoPurge();
+ }
+
+ queues[id] = Y.merge(opts, {
+ tId: id,
+ type: type,
+ url: url,
+ finished: false,
+ nodes: []
+ });
+
+ q = queues[id];
+ q.win = q.win || Y.config.win;
+ q.context = q.context || q;
+ q.autopurge = ("autopurge" in q) ? q.autopurge :
+ (type === "script") ? true : false;
+
+ if (opts.charset) {
+ q.attributes = q.attributes || {};
+ q.attributes.charset = opts.charset;
+ }
+
+ // L.later(0, q, _next, id);
+ setTimeout(function() {
+ _next(id);
+ }, 0);
+
+ return {
+ tId: id
+ };
+ },
+
+ /**
+ * Detects when a node has been loaded. In the case of
+ * script nodes, this does not guarantee that contained
+ * script is ready to use.
+ * @method _track
+ * @param type {string} the type of node to track
+ * @param n {HTMLElement} the node to track
+ * @param id {string} the id of the request
+ * @param url {string} the url that is being loaded
+ * @param win {Window} the targeted window
+ * @param qlength the number of remaining items in the queue,
+ * including this one
+ * @param trackfn {Function} function to execute when finished
+ * the default is _next
+ * @private
+ */
+ _track = function(type, n, id, url, win, qlength, trackfn) {
+ var f = trackfn || _next;
+
+ // IE supports the readystatechange event for script and css nodes
+ // Opera only for script nodes. Opera support onload for script
+ // nodes, but this doesn't fire when there is a load failure.
+ // The onreadystatechange appears to be a better way to respond
+ // to both success and failure.
+ if (ua.ie) {
+ n.onreadystatechange = function() {
+ var rs = this.readyState;
+ if ("loaded" === rs || "complete" === rs) {
+ Y.log(id + " onreadstatechange " + url, "info", "get");
+ n.onreadystatechange = null;
+ f(id, url);
+ }
+ };
+
+ // webkit prior to 3.x is no longer supported
+ } else if (ua.webkit) {
+
+ if (type === "script") {
+ // Safari 3.x supports the load event for script nodes (DOM2)
+ n.addEventListener("load", function() {
+ Y.log(id + " DOM2 onload " + url, "info", "get");
+ f(id, url);
+ });
+ }
+
+ // FireFox and Opera support onload (but not DOM2 in FF) handlers for
+ // script nodes. Opera, but not FF, supports the onload event for link
+ // nodes.
+ } else {
+
+ n.onload = function() {
+ Y.log(id + " onload " + url, "info", "get");
+ f(id, url);
+ };
+
+ n.onerror = function(e) {
+ _fail(id, e + ": " + url);
+ };
+ }
+ };
+
+ return {
+
+ /**
+ * The number of request required before an automatic purge.
+ * Can be configured via the 'purgethreshold' config
+ * property PURGE_THRESH
+ * @static
+ * @type int
+ * @default 20
+ * @private
+ */
+ PURGE_THRESH: 20,
+
+ /**
+ * Called by the the helper for detecting script load in Safari
+ * @method _finalize
+ * @static
+ * @param id {string} the transaction id
+ * @private
+ */
+ _finalize: function(id) {
+ Y.log(id + " finalized ", "info", "get");
+ // L.later(0, null, _finish, id);
+ setTimeout(function() {
+ _finish(id);
+ }, 0);
+ },
+
+ /**
+ * Abort a transaction
+ * @method abort
+ * @static
+ * @param o {string|object} Either the tId or the object returned from
+ * script() or css()
+ */
+ abort: function(o) {
+ var id = (L.isString(o)) ? o : o.tId,
+ q = queues[id];
+ if (q) {
+ Y.log("Aborting " + id, "info", "get");
+ q.aborted = true;
+ }
+ },
+
+ /**
+ * Fetches and inserts one or more script nodes into the head
+ * of the current document or the document in a specified window.
+ *
+ * @method script
+ * @static
+ * @param url {string|string[]} the url or urls to the script(s)
+ * @param opts {object} Options:
+ * <dl>
+ * <dt>onSuccess</dt>
+ * <dd>
+ * callback to execute when the script(s) are finished loading
+ * The callback receives an object back with the following
+ * data:
+ * <dl>
+ * <dt>win</dt>
+ * <dd>the window the script(s) were inserted into</dd>
+ * <dt>data</dt>
+ * <dd>the data object passed in when the request was made</dd>
+ * <dt>nodes</dt>
+ * <dd>An array containing references to the nodes that were
+ * inserted</dd>
+ * <dt>purge</dt>
+ * <dd>A function that, when executed, will remove the nodes
+ * that were inserted</dd>
+ * <dt>
+ * </dl>
+ * </dd>
+ * <dt>onTimeout</dt>
+ * <dd>
+ * callback to execute when a timeout occurs.
+ * The callback receives an object back with the following
+ * data:
+ * <dl>
+ * <dt>win</dt>
+ * <dd>the window the script(s) were inserted into</dd>
+ * <dt>data</dt>
+ * <dd>the data object passed in when the request was made</dd>
+ * <dt>nodes</dt>
+ * <dd>An array containing references to the nodes that were
+ * inserted</dd>
+ * <dt>purge</dt>
+ * <dd>A function that, when executed, will remove the nodes
+ * that were inserted</dd>
+ * <dt>
+ * </dl>
+ * </dd>
+ * <dt>onEnd</dt>
+ * <dd>a function that executes when the transaction finishes, regardless of the exit path</dd>
+ * <dt>onFailure</dt>
+ * <dd>
+ * callback to execute when the script load operation fails
+ * The callback receives an object back with the following
+ * data:
+ * <dl>
+ * <dt>win</dt>
+ * <dd>the window the script(s) were inserted into</dd>
+ * <dt>data</dt>
+ * <dd>the data object passed in when the request was made</dd>
+ * <dt>nodes</dt>
+ * <dd>An array containing references to the nodes that were
+ * inserted successfully</dd>
+ * <dt>purge</dt>
+ * <dd>A function that, when executed, will remove any nodes
+ * that were inserted</dd>
+ * <dt>
+ * </dl>
+ * </dd>
+ * <dt>context</dt>
+ * <dd>the execution context for the callbacks</dd>
+ * <dt>win</dt>
+ * <dd>a window other than the one the utility occupies</dd>
+ * <dt>autopurge</dt>
+ * <dd>
+ * setting to true will let the utilities cleanup routine purge
+ * the script once loaded
+ * </dd>
+ * <dt>purgethreshold</dt>
+ * <dd>
+ * The number of transaction before autopurge should be initiated
+ * </dd>
+ * <dt>data</dt>
+ * <dd>
+ * data that is supplied to the callback when the script(s) are
+ * loaded.
+ * </dd>
+ * <dt>insertBefore</dt>
+ * <dd>node or node id that will become the new node's nextSibling</dd>
+ * </dl>
+ * <dt>charset</dt>
+ * <dd>Node charset, default utf-8 (deprecated, use the attributes config)</dd>
+ * <dt>attributes</dt>
+ * <dd>An object literal containing additional attributes to add to the link tags</dd>
+ * <dt>timeout</dt>
+ * <dd>Number of milliseconds to wait before aborting and firing the timeout event</dd>
+ * <pre>
+ * Y.Get.script(
+ * ["http://yui.yahooapis.com/2.5.2/build/yahoo/yahoo-min.js",
+ * "http://yui.yahooapis.com/2.5.2/build/event/event-min.js"], {
+ * onSuccess: function(o) {
+ * this.log("won't cause error because Y is the context");
+ * Y.log(o.data); // foo
+ * Y.log(o.nodes.length === 2) // true
+ * // o.purge(); // optionally remove the script nodes immediately
+ * },
+ * onFailure: function(o) {
+ * Y.log("transaction failed");
+ * },
+ * onTimeout: function(o) {
+ * Y.log("transaction timed out");
+ * },
+ * data: "foo",
+ * timeout: 10000, // 10 second timeout
+ * context: Y, // make the YUI instance
+ * // win: otherframe // target another window/frame
+ * autopurge: true // allow the utility to choose when to remove the nodes
+ * purgetheshold: 1 // purge previous transaction before next transaction
+ * });
+ * </pre>
+ * @return {tId: string} an object containing info about the transaction
+ */
+ script: function(url, opts) {
+ return _queue("script", url, opts);
+ },
+
+ /**
+ * Fetches and inserts one or more css link nodes into the
+ * head of the current document or the document in a specified
+ * window.
+ * @method css
+ * @static
+ * @param url {string} the url or urls to the css file(s)
+ * @param opts Options:
+ * <dl>
+ * <dt>onSuccess</dt>
+ * <dd>
+ * callback to execute when the css file(s) are finished loading
+ * The callback receives an object back with the following
+ * data:
+ * <dl>win</dl>
+ * <dd>the window the link nodes(s) were inserted into</dd>
+ * <dt>data</dt>
+ * <dd>the data object passed in when the request was made</dd>
+ * <dt>nodes</dt>
+ * <dd>An array containing references to the nodes that were
+ * inserted</dd>
+ * <dt>purge</dt>
+ * <dd>A function that, when executed, will remove the nodes
+ * that were inserted</dd>
+ * <dt>
+ * </dl>
+ * </dd>
+ * <dt>context</dt>
+ * <dd>the execution context for the callbacks</dd>
+ * <dt>win</dt>
+ * <dd>a window other than the one the utility occupies</dd>
+ * <dt>data</dt>
+ * <dd>
+ * data that is supplied to the callbacks when the nodes(s) are
+ * loaded.
+ * </dd>
+ * <dt>insertBefore</dt>
+ * <dd>node or node id that will become the new node's nextSibling</dd>
+ * <dt>charset</dt>
+ * <dd>Node charset, default utf-8 (deprecated, use the attributes config)</dd>
+ * <dt>attributes</dt>
+ * <dd>An object literal containing additional attributes to add to the link tags</dd>
+ * </dl>
+ * <pre>
+ * Y.Get.css("http://yui.yahooapis.com/2.3.1/build/menu/assets/skins/sam/menu.css");
+ * </pre>
+ * <pre>
+ * Y.Get.css(
+ * ["http://yui.yahooapis.com/2.3.1/build/menu/assets/skins/sam/menu.css",
+ * "http://yui.yahooapis.com/2.3.1/build/logger/assets/skins/sam/logger.css"], {
+ * insertBefore: 'custom-styles' // nodes will be inserted before the specified node
+ * });
+ * </pre>
+ * @return {tId: string} an object containing info about the transaction
+ */
+ css: function(url, opts) {
+ return _queue("css", url, opts);
+ }
+ };
+}();
+
+})();
+