Version 3.18.1
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File: widget/js/WidgetUIEvents.js

            /**
             * Support for Widget UI Events (Custom Events fired by the widget, which wrap the underlying DOM events - e.g. widget:click, widget:mousedown)
             *
             * @module widget
             * @submodule widget-uievents
             */
            
            var BOUNDING_BOX = "boundingBox",
                Widget = Y.Widget,
                RENDER = "render",
                L = Y.Lang,
                EVENT_PREFIX_DELIMITER = ":",
            
                //  Map of Node instances serving as a delegation containers for a specific
                //  event type to Widget instances using that delegation container.
                _uievts = Y.Widget._uievts = Y.Widget._uievts || {};
            
            Y.mix(Widget.prototype, {
            
                /**
                 * Destructor logic for UI event infrastructure,
                 * invoked during Widget destruction.
                 *
                 * @method _destroyUIEvents
                 * @for Widget
                 * @private
                 */
                _destroyUIEvents: function() {
            
                    var widgetGuid = Y.stamp(this, true);
            
                    Y.each(_uievts, function (info, key) {
                        if (info.instances[widgetGuid]) {
                            //  Unregister this Widget instance as needing this delegated
                            //  event listener.
                            delete info.instances[widgetGuid];
            
                            //  There are no more Widget instances using this delegated
                            //  event listener, so detach it.
            
                            if (Y.Object.isEmpty(info.instances)) {
                                info.handle.detach();
            
                                if (_uievts[key]) {
                                    delete _uievts[key];
                                }
                            }
                        }
                    });
                },
            
                /**
                 * Map of DOM events that should be fired as Custom Events by the
                 * Widget instance.
                 *
                 * @property UI_EVENTS
                 * @for Widget
                 * @type Object
                 */
                UI_EVENTS: Y.Node.DOM_EVENTS,
            
                /**
                 * Returns the node on which to bind delegate listeners.
                 *
                 * @method _getUIEventNode
                 * @for Widget
                 * @protected
                 */
                _getUIEventNode: function () {
                    return this.get(BOUNDING_BOX);
                },
            
                /**
                 * Binds a delegated DOM event listener of the specified type to the
                 * Widget's outtermost DOM element to facilitate the firing of a Custom
                 * Event of the same type for the Widget instance.
                 *
                 * @method _createUIEvent
                 * @for Widget
                 * @param type {String} String representing the name of the event
                 * @private
                 */
                _createUIEvent: function (type) {
            
                    var uiEvtNode = this._getUIEventNode(),
                        key = (Y.stamp(uiEvtNode) + type),
                        info = _uievts[key],
                        handle;
            
                    //  For each Node instance: Ensure that there is only one delegated
                    //  event listener used to fire Widget UI events.
            
                    if (!info) {
            
                        handle = uiEvtNode.delegate(type, function (evt) {
            
                            var widget = Widget.getByNode(this);
            
                            // Widget could be null if node instance belongs to
                            // another Y instance.
            
                            if (widget) {
                                if (widget._filterUIEvent(evt)) {
                                    widget.fire(evt.type, { domEvent: evt });
                                }
                            }
            
                        }, "." + Y.Widget.getClassName());
            
                        _uievts[key] = info = { instances: {}, handle: handle };
                    }
            
                    //  Register this Widget as using this Node as a delegation container.
                    info.instances[Y.stamp(this)] = 1;
                },
            
                /**
                 * This method is used to determine if we should fire
                 * the UI Event or not. The default implementation makes sure
                 * that for nested delegates (nested unrelated widgets), we don't
                 * fire the UI event listener more than once at each level.
                 *
                 * <p>For example, without the additional filter, if you have nested
                 * widgets, each widget will have a delegate listener. If you
                 * click on the inner widget, the inner delegate listener's
                 * filter will match once, but the outer will match twice
                 * (based on delegate's design) - once for the inner widget,
                 * and once for the outer.</p>
                 *
                 * @method _filterUIEvent
                 * @for Widget
                 * @param {DOMEventFacade} evt
                 * @return {boolean} true if it's OK to fire the custom UI event, false if not.
                 * @private
                 *
                 */
                _filterUIEvent: function(evt) {
                    // Either it's hitting this widget's delegate container (and not some other widget's),
                    // or the container it's hitting is handling this widget's ui events.
                    return (evt.currentTarget.compareTo(evt.container) || evt.container.compareTo(this._getUIEventNode()));
                },
            
                /**
                 * Determines if the specified event is a UI event.
                 *
                 * @private
                 * @method _isUIEvent
                 * @for Widget
                 * @param type {String} String representing the name of the event
                 * @return {String} Event Returns the name of the UI Event, otherwise
                 * undefined.
                 */
                _getUIEvent: function (type) {
            
                    if (L.isString(type)) {
                        var sType = this.parseType(type)[1],
                            iDelim,
                            returnVal;
            
                        if (sType) {
                            // TODO: Get delimiter from ET, or have ET support this.
                            iDelim = sType.indexOf(EVENT_PREFIX_DELIMITER);
                            if (iDelim > -1) {
                                sType = sType.substring(iDelim + EVENT_PREFIX_DELIMITER.length);
                            }
            
                            if (this.UI_EVENTS[sType]) {
                                returnVal = sType;
                            }
                        }
            
                        return returnVal;
                    }
                },
            
                /**
                 * Sets up infrastructure required to fire a UI event.
                 *
                 * @private
                 * @method _initUIEvent
                 * @for Widget
                 * @param type {String} String representing the name of the event
                 * @return {String}
                 */
                _initUIEvent: function (type) {
                    var sType = this._getUIEvent(type),
                        queue = this._uiEvtsInitQueue || {};
            
                    if (sType && !queue[sType]) {
                        Y.log("Deferring creation of " + type + " delegate until render.", "info", "widget");
            
                        this._uiEvtsInitQueue = queue[sType] = 1;
            
                        this.after(RENDER, function() {
                            this._createUIEvent(sType);
                            delete this._uiEvtsInitQueue[sType];
                        });
                    }
                },
            
                //  Override of "on" from Base to facilitate the firing of Widget events
                //  based on DOM events of the same name/type (e.g. "click", "mouseover").
                //  Temporary solution until we have the ability to listen to when
                //  someone adds an event listener (bug 2528230)
                on: function (type) {
                    this._initUIEvent(type);
                    return Widget.superclass.on.apply(this, arguments);
                },
            
                //  Override of "publish" from Base to facilitate the firing of Widget events
                //  based on DOM events of the same name/type (e.g. "click", "mouseover").
                //  Temporary solution until we have the ability to listen to when
                //  someone publishes an event (bug 2528230)
                publish: function (type, config) {
                    var sType = this._getUIEvent(type);
                    if (sType && config && config.defaultFn) {
                        this._initUIEvent(sType);
                    }
                    return Widget.superclass.publish.apply(this, arguments);
                }
            
            }, true); // overwrite existing EventTarget methods