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event  3.0.0pr2

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/*
 * The YUI DOM event system
 * @submodule event-dom
 * @module event
 */
(function() {

    var add = function(el, type, fn, capture) {
        if (el.addEventListener) {
                el.addEventListener(type, fn, !!capture);
        } else if (el.attachEvent) {
                el.attachEvent("on" + type, fn);
        } 
    },

    remove = function(el, type, fn, capture) {
        if (el.removeEventListener) {
                el.removeEventListener(type, fn, !!capture);
        } else if (el.detachEvent) {
                el.detachEvent("on" + type, fn);
        }
    },

    onLoad = function() {
        YUI.Env.windowLoaded = true;
        remove(window, "load", onLoad);
    },

    EVENT_READY = 'domready',

    COMPAT_ARG = '~yui|2|compat~',

    CAPTURE = "capture_";

add(window, "load", onLoad);

YUI.add("event-dom", function(Y) {

    /**
     * The event utility provides functions to add and remove event listeners,
     * event cleansing.  It also tries to automatically remove listeners it
     * registers during the unload event.
     *
     * @class Event
     * @static
     */
    Y.Event = function() {

        /**
         * True after the onload event has fired
         * @property loadComplete
         * @type boolean
         * @static
         * @private
         */
        var loadComplete =  false;

        /**
         * The number of times to poll after window.onload.  This number is
         * increased if additional late-bound handlers are requested after
         * the page load.
         * @property _retryCount
         * @static
         * @private
         */
        var _retryCount = 0;

        /**
         * onAvailable listeners
         * @property _avail
         * @static
         * @private
         */
        var _avail = [];

        /**
         * Custom event wrappers for DOM events.  Key is 
         * 'event:' + Element uid stamp + event type
         * @property _wrappers
         * @type Y.Event.Custom
         * @static
         * @private
         */
        var _wrappers = {};

        var _windowLoadKey = null;

        /**
         * Custom event wrapper map DOM events.  Key is 
         * Element uid stamp.  Each item is a hash of custom event
         * wrappers as provided in the _wrappers collection.  This
         * provides the infrastructure for getListeners.
         * @property _el_events
         * @static
         * @private
         */
        var _el_events = {};

        return {

            /**
             * The number of times we should look for elements that are not
             * in the DOM at the time the event is requested after the document
             * has been loaded.  The default is 2000@amp;20 ms, so it will poll
             * for 40 seconds or until all outstanding handlers are bound
             * (whichever comes first).
             * @property POLL_RETRYS
             * @type int
             * @static
             * @final
             */
            POLL_RETRYS: 2000,

            /**
             * The poll interval in milliseconds
             * @property POLL_INTERVAL
             * @type int
             * @static
             * @final
             */
            POLL_INTERVAL: 20,

            /**
             * addListener/removeListener can throw errors in unexpected scenarios.
             * These errors are suppressed, the method returns false, and this property
             * is set
             * @property lastError
             * @static
             * @type Error
             */
            lastError: null,


            /**
             * poll handle
             * @property _interval
             * @static
             * @private
             */
            _interval: null,

            /**
             * document readystate poll handle
             * @property _dri
             * @static
             * @private
             */
             _dri: null,

            /**
             * True when the document is initially usable
             * @property DOMReady
             * @type boolean
             * @static
             */
            DOMReady: false,

            /**
             * @method startInterval
             * @static
             * @private
             */
            startInterval: function() {
                var E = Y.Event;

                if (!E._interval) {
E._interval = setInterval(Y.bind(E._tryPreloadAttach, E), E.POLL_INTERVAL);
                }
            },

            /**
             * Executes the supplied callback when the item with the supplied
             * id is found.  This is meant to be used to execute behavior as
             * soon as possible as the page loads.  If you use this after the
             * initial page load it will poll for a fixed time for the element.
             * The number of times it will poll and the frequency are
             * configurable.  By default it will poll for 10 seconds.
             *
             * <p>The callback is executed with a single parameter:
             * the custom object parameter, if provided.</p>
             *
             * @method onAvailable
             *
             * @param {string||string[]}   id the id of the element, or an array
             * of ids to look for.
             * @param {function} fn what to execute when the element is found.
             * @param {object}   p_obj an optional object to be passed back as
             *                   a parameter to fn.
             * @param {boolean|object}  p_override If set to true, fn will execute
             *                   in the context of p_obj, if set to an object it
             *                   will execute in the context of that object
             * @param checkContent {boolean} check child node readiness (onContentReady)
             * @static
             * @deprecated Use Y.on("available")
             */
            // @TODO fix arguments
            onAvailable: function(id, fn, p_obj, p_override, checkContent, compat) {

                var a = Y.Array(id);

                // Y.log('onAvailable registered for: ' + id);

                for (var i=0; i<a.length; i=i+1) {
                    _avail.push({ 
                        id:         a[i], 
                        fn:         fn, 
                        obj:        p_obj, 
                        override:   p_override, 
                        checkReady: checkContent,
                        compat:     compat 
                    });
                }
                _retryCount = this.POLL_RETRYS;

                // We want the first test to be immediate, but async
                setTimeout(Y.bind(Y.Event._tryPreloadAttach, Y.Event), 0);

                return new Y.EventHandle(); // @TODO by id needs a defered handle
            },

            /**
             * Works the same way as onAvailable, but additionally checks the
             * state of sibling elements to determine if the content of the
             * available element is safe to modify.
             *
             * <p>The callback is executed with a single parameter:
             * the custom object parameter, if provided.</p>
             *
             * @method onContentReady
             *
             * @param {string}   id the id of the element to look for.
             * @param {function} fn what to execute when the element is ready.
             * @param {object}   p_obj an optional object to be passed back as
             *                   a parameter to fn.
             * @param {boolean|object}  p_override If set to true, fn will execute
             *                   in the context of p_obj.  If an object, fn will
             *                   exectute in the context of that object
             *
             * @static
             * @deprecated Use Y.on("contentready")
             */
            // @TODO fix arguments
            onContentReady: function(id, fn, p_obj, p_override, compat) {
                return this.onAvailable(id, fn, p_obj, p_override, true, compat);
            },


            /**
             * Appends an event handler
             *
             * @method attach
             *
             * @param {String}   type     The type of event to append
             * @param {Function} fn        The method the event invokes
             * @param {String|HTMLElement|Array|NodeList} el An id, an element 
             *  reference, or a collection of ids and/or elements to assign the 
             *  listener to.
             * @param {Object}   obj    An arbitrary object that will be 
             *                             passed as a parameter to the handler
             * @param {Boolean|object}  args 1..n ar
             * @return {Boolean} True if the action was successful or defered,
             *                        false if one or more of the elements 
             *                        could not have the listener attached,
             *                        or if the operation throws an exception.
             * @static
             */
            attach: function(type, fn, el, obj) {

                // Y.log('attach: ' + Y.Lang.dump(Y.Array(arguments, 0, true), 1));
                // Y.log('attach:');
                // Y.log(Y.Array(arguments, 0, true), 1);
                // var a=Y.Array(arguments, 1, true), override=a[3], E=Y.Event, aa=Y.Array(arguments, 0, true);

                var args=Y.Array(arguments, 0, true), 
                    trimmedArgs=args.slice(1),
                    compat, E=Y.Event, capture = false;

                if (type.indexOf(CAPTURE) > -1) {
                    type = type.substr(CAPTURE.length);
                    capture = true;
                    Y.log('Using capture phase for: ' + type, 'info', 'event');
                }

                if (trimmedArgs[trimmedArgs.length-1] === COMPAT_ARG) {
                    compat = true;
                    trimmedArgs.pop();
                }

                if (!fn || !fn.call) {
// throw new TypeError(type + " attach call failed, callback undefined");
Y.log(type + " attach call failed, invalid callback", "error", "event");
                    return false;
                }

                // The el argument can be an array of elements or element ids.
                if (this._isValidCollection(el)) {

                    // Y.log('collection: ' + el);
                    // Y.log('collection: ' + el.item(0) + ', ' + el.item(1));

                    var handles=[], i, l;
                    
                    Y.each(el, function(v, k) {
                        args[2] = v;
                        handles.push(E.attach.apply(E, args));
                    });

                    return handles;


                } else if (Y.Lang.isString(el)) {

                    var oEl = (compat) ? Y.DOM.byId(el) : Y.all(el);

                    // If the el argument is a string, we assume it is 
                    // actually the id of the element.  If the page is loaded
                    // we convert el to the actual element, otherwise we 
                    // defer attaching the event until onload event fires

                    // check to see if we need to delay hooking up the event 
                    // until after the page loads.

                    // Node collection
                    // if (oEl && oEl.size && oEl.size() > 0) {
                    //
                    // Y.log('node?: ' + (oEl instanceof Y.Node));

                    /*
                    if (oEl) {
                        el = oEl;
                    */

                    if (oEl && (oEl instanceof Y.Node)) {
                        var size = oEl.size();
                        if (size > 1) {
                            // Y.log('more than one: ' + size + ', ' + type);
                            // args[0] = oEl;
                            args[2] = oEl;
                            return E.attach.apply(E, args);
                        } else {
                            // Y.log('just one: ' + size + ', ' + type);
                            el = oEl.item(0);
                            // el = oEl;
                        }

                    // HTMLElement
                    // } else if (compat && oEl) {
                    } else if (oEl) {
                        // Y.log('no size: ' + oEl + ', ' + type);
                        el = oEl;

                    // Not found = defer adding the event until the element is available
                    } else {

                        // Y.log(el + ' not found');

                        return this.onAvailable(el, function() {
                            // Y.log('lazy attach: ' + args);
                            E.attach.apply(E, args);
                        }, E, true, false, compat);
                    }
                }

                // Element should be an html element or an array if we get here.
                if (!el) {
                    Y.log("unable to attach event " + type, "warn", "event");
                    return false;
                }

                // the custom event key is the uid for the element + type

                var ek = Y.stamp(el), key = 'event:' + ek + type,
                    cewrapper = _wrappers[key];


                if (!cewrapper) {
                    // create CE wrapper
                    cewrapper = Y.publish(key, {
                        silent: true,
                        // host: this,
                        bubbles: false
                    });

                    // cache the dom event details in the custom event
                    // for later removeListener calls
                    cewrapper.el = el;
                    cewrapper.type = type;
                    cewrapper.fn = function(e) {
                        cewrapper.fire(E.getEvent(e, el, compat));
                    };

                    if (el == Y.config.win && type == "load") {
                        // window load happens once
                        cewrapper.fireOnce = true;
                        _windowLoadKey = key;

                        // if the load is complete, fire immediately.
                        // all subscribers, including the current one
                        // will be notified.
                        if (YUI.Env.windowLoaded) {
                            cewrapper.fire();
                        }
                    }

                    _wrappers[key] = cewrapper;
                    _el_events[ek] = _el_events[ek] || {};
                    _el_events[ek][key] = cewrapper;

                    // var capture = (Y.lang.isObject(obj) && obj.capture);
                    // attach a listener that fires the custom event

                    // Y.log("Attaching listener: " + [el, type, cewrapper.fn, capture]);
                    add(el, type, cewrapper.fn, capture);
                }

                // switched from obj to trimmedArgs[2] to deal with appened compat param
                var context = trimmedArgs[2] || ((compat) ? el : Y.get(el));
                
                // set the context as the second arg to subscribe
                trimmedArgs[1] = context;

                // remove the 'obj' param
                trimmedArgs.splice(2, 1);

                // set context to the Node if not specified
                return cewrapper.subscribe.apply(cewrapper, trimmedArgs);

            },

            /**
             * Removes an event listener.  Supports the signature the event was bound
             * with, but the preferred way to remove listeners is using the handle
             * that is returned when using Y.on
             *
             * @method detach
             *
             * @param {String|HTMLElement|Array|NodeList} el An id, an element 
             *  reference, or a collection of ids and/or elements to remove
             *  the listener from.
             * @param {String} type the type of event to remove.
             * @param {Function} fn the method the event invokes.  If fn is
             *  undefined, then all event handlers for the type of event are *  removed.
             * @return {boolean} true if the unbind was successful, false *  otherwise.
             * @static
             */
            detach: function(type, fn, el, obj) {

                var args=Y.Array(arguments, 0, true), compat;

                if (args[args.length-1] === COMPAT_ARG) {
                    compat = true;
                    // args.pop();
                }

                if (type && type.detach) {
                    return type.detach();
                }

                var i, len, li;

                // The el argument can be a string
                if (typeof el == "string") {

                    el = (compat) ? Y.DOM.byId(el) : Y.all(el);

                // The el argument can be an array of elements or element ids.
                } else if ( this._isValidCollection(el)) {

                    var ok = true;
                    for (i=0, len=el.length; i<len; ++i) {

                        args[2] = el[i];

                        // ok = ( this.detach(el[i], type, fn) && ok );
                        ok = ( Y.Event.detach.apply(Y.Event, args) && ok );
                    }

                    return ok;

                }

                if (!fn || !fn.call) {
                    return this.purgeElement(el, false, type);
                }

                var id = 'event:' + Y.stamp(el) + type, 
                    ce = _wrappers[id];
                if (ce) {
                    return ce.unsubscribe(fn);
                } else {
                    return false;
                }

            },

            /**
             * Finds the event in the window object, the caller's arguments, or
             * in the arguments of another method in the callstack.  This is
             * executed automatically for events registered through the event
             * manager, so the implementer should not normally need to execute
             * this function at all.
             * @method getEvent
             * @param {Event} e the event parameter from the handler
             * @param {HTMLElement} el the element the listener was attached to
             * @return {Event} the event 
             * @static
             */
            getEvent: function(e, el, noFacade) {
                var ev = e || window.event;

                return (noFacade) ? ev : 
                    new Y.Event.Facade(ev, el, _wrappers['event:' + Y.stamp(el) + e.type]);
            },

            /**
             * Generates an unique ID for the element if it does not already 
             * have one.
             * @method generateId
             * @param el the element to create the id for
             * @return {string} the resulting id of the element
             * @static
             */
            generateId: function(el) {
                var id = el.id;

                if (!id) {
                    id = Y.stamp(el);
                    el.id = id;
                }

                return id;
            },

            /**
             * We want to be able to use getElementsByTagName as a collection
             * to attach a group of events to.  Unfortunately, different 
             * browsers return different types of collections.  This function
             * tests to determine if the object is array-like.  It will also 
             * fail if the object is an array, but is empty.
             * @method _isValidCollection
             * @param o the object to test
             * @return {boolean} true if the object is array-like and populated
             * @static
             * @private
             */
            _isValidCollection: function(o) {
                try {
                     
                    // Y.log('node? ' + (o instanceof Y.Node) + ', ' + ((o.size) ? o.size() : ' no size'));
                    // if (o instanceof Y.Node) {
                        // o.tagName ="adsf";
                    // }

                    return ( o                     && // o is something
                             typeof o !== "string" && // o is not a string
                             // o.length  && // o is indexed
                             (o.length && ((!o.size) || (o.size() > 1)))  && // o is indexed
                             !o.tagName            && // o is not an HTML element
                             !o.alert              && // o is not a window
                             (o.item || typeof o[0] !== "undefined") );
                } catch(ex) {
                    Y.log("collection check failure", "warn", "event");
                    return false;
                }

            },

            /**
             * hook up any deferred listeners
             * @method _load
             * @static
             * @private
             */
            _load: function(e) {

                if (!loadComplete) {

                    // Y.log('Load Complete', 'info', 'event');

                    loadComplete = true;

                    // Just in case DOMReady did not go off for some reason
                    // E._ready();
                    if (Y.fire) {
                        Y.fire(EVENT_READY);
                    }

                    // Available elements may not have been detected before the
                    // window load event fires. Try to find them now so that the
                    // the user is more likely to get the onAvailable notifications
                    // before the window load notification
                    Y.Event._tryPreloadAttach();

                }
            },

            /**
             * Polling function that runs before the onload event fires, 
             * attempting to attach to DOM Nodes as soon as they are 
             * available
             * @method _tryPreloadAttach
             * @static
             * @private
             */
            _tryPreloadAttach: function() {

                if (this.locked) {
                    return;
                }

                if (Y.UA.ie && !YUI.Env.DOMReady) {
                    // Hold off if DOMReady has not fired and check current
                    // readyState to protect against the IE operation aborted
                    // issue.
                    this.startInterval();
                    return;
                }

                this.locked = true;

                // Y.log.debug("tryPreloadAttach");

                // keep trying until after the page is loaded.  We need to 
                // check the page load state prior to trying to bind the 
                // elements so that we can be certain all elements have been 
                // tested appropriately
                var tryAgain = !loadComplete;
                if (!tryAgain) {
                    tryAgain = (_retryCount > 0);
                }

                // onAvailable
                var notAvail = [];

                var executeItem = function (el, item) {
                    var context, ov = item.override;

                    if (item.compat) {

                        if (item.override) {
                            if (ov === true) {
                                context = item.obj;
                            } else {
                                context = ov;
                            }
                        } else {
                            context = el;
                        }

                        item.fn.call(context, item.obj);

                    } else {
                        context = item.obj || Y.get(el);
                        item.fn.apply(context, (Y.Lang.isArray(ov)) ? ov : []);
                    }

                };

                var i, len, item, el;

                // onAvailable
                for (i=0,len=_avail.length; i<len; ++i) {
                    item = _avail[i];
                    if (item && !item.checkReady) {

                        el = (item.compat) ? Y.DOM.byId(item.id) : Y.get(item.id);

                        if (el) {
                            // Y.log('avail: ' + el);
                            executeItem(el, item);
                            _avail[i] = null;
                        } else {
                            // Y.log('NOT avail: ' + el);
                            notAvail.push(item);
                        }
                    }
                }

                // onContentReady
                for (i=0,len=_avail.length; i<len; ++i) {
                    item = _avail[i];
                    if (item && item.checkReady) {

                        el = (item.compat) ? Y.DOM.byId(item.id) : Y.get(item.id);

                        if (el) {
                            // The element is available, but not necessarily ready
                            // @todo should we test parentNode.nextSibling?
                            if (loadComplete || (el.get && el.get('nextSibling')) || el.nextSibling) {
                                executeItem(el, item);
                                _avail[i] = null;
                            }
                        } else {
                            notAvail.push(item);
                        }
                    }
                }

                _retryCount = (notAvail.length === 0) ? 0 : _retryCount - 1;

                if (tryAgain) {
                    // we may need to strip the nulled out items here
                    this.startInterval();
                } else {
                    clearInterval(this._interval);
                    this._interval = null;
                }

                this.locked = false;

                return;

            },

            /**
             * Removes all listeners attached to the given element via addListener.
             * Optionally, the node's children can also be purged.
             * Optionally, you can specify a specific type of event to remove.
             * @method purgeElement
             * @param {HTMLElement} el the element to purge
             * @param {boolean} recurse recursively purge this element's children
             * as well.  Use with caution.
             * @param {string} type optional type of listener to purge. If
             * left out, all listeners will be removed
             * @static
             */
            purgeElement: function(el, recurse, type) {
                var oEl = (Y.Lang.isString(el)) ? Y.get(el) : el,
                    id = Y.stamp(oEl);
                var lis = this.getListeners(oEl, type), i, len;
                if (lis) {
                    for (i=0,len=lis.length; i<len ; ++i) {
                        lis[i].unsubscribeAll();
                    }
                }

                if (recurse && oEl && oEl.childNodes) {
                    for (i=0,len=oEl.childNodes.length; i<len ; ++i) {
                        this.purgeElement(oEl.childNodes[i], recurse, type);
                    }
                }
            },

            /**
             * Returns all listeners attached to the given element via addListener.
             * Optionally, you can specify a specific type of event to return.
             * @method getListeners
             * @param el {HTMLElement|string} the element or element id to inspect 
             * @param type {string} optional type of listener to return. If
             * left out, all listeners will be returned
             * @return {Y.Custom.Event} the custom event wrapper for the DOM event(s)
             * @static
             */           
            getListeners: function(el, type) {
                var ek = Y.stamp(el), evts = _el_events[ek];

                if (!evts) {
                    return null;
                }

                var results=[] , key = (type) ? 'event:' + type : null;

                if (key) {
                    if (evts[key]) {
                        results.push(evts[key]);
                    }
                } else {
                    Y.each(evts, function(v, k) {
                        results.push(v);
                    });
                }

                return (results.length) ? results : null;
            },

            /**
             * Removes all listeners registered by pe.event.  Called 
             * automatically during the unload event.
             * @method _unload
             * @static
             * @private
             */
            _unload: function(e) {

                var E = Y.Event;

                Y.each(_wrappers, function(v, k) {
                    v.unsubscribeAll();
                    remove(v.el, v.type, v.fn);
                    delete _wrappers[k];
                });

                remove(window, "load", E._load);
                remove(window, "unload", E._unload);
            },

            
            /**
             * Adds a DOM event directly without the caching, cleanup, context adj, etc
             *
             * @method nativeAdd
             * @param {HTMLElement} el      the element to bind the handler to
             * @param {string}      type   the type of event handler
             * @param {function}    fn      the callback to invoke
             * @param {boolen}      capture capture or bubble phase
             * @static
             * @private
             */
            nativeAdd: add,

            /**
             * Basic remove listener
             *
             * @method nativeRemove
             * @param {HTMLElement} el      the element to bind the handler to
             * @param {string}      type   the type of event handler
             * @param {function}    fn      the callback to invoke
             * @param {boolen}      capture capture or bubble phase
             * @static
             * @private
             */
            nativeRemove: remove
        };

    }();

    var E = Y.Event;

    // Process onAvailable/onContentReady items when when the DOM is ready in IE
    if (Y.UA.ie && Y.on) {
        Y.on(EVENT_READY, E._tryPreloadAttach, E, true);
    }

    E.Custom = Y.CustomEvent;
    E.Subscriber = Y.Subscriber;
    E.Target = Y.EventTarget;

    add(window, "load", E._load);
    add(window, "unload", E._unload);

    E._tryPreloadAttach();

}, "3.0.0");

})();

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