event.js

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/*
Copyright (c) 2006, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.net/yui/license.txt
Version: 0.11.4
*/

/**
 * The CustomEvent class lets you define events for your application
 * that can be subscribed to by one or more independent component.
 *
 * @param {String}  type The type of event, which is passed to the callback
 *                  when the event fires
 * @param {Object}  oScope The context the event will fire from.  "this" will
 *                  refer to this object in the callback.  Default value:
 *                  the window object.  The listener can override this.
 * @param {boolean} silent pass true to prevent the event from writing to
 *                  the log system
 * @namespace YAHOO.util
 * @class CustomEvent
 * @constructor
 */
YAHOO.util.CustomEvent = function(type, oScope, silent) {

    /**
     * The type of event, returned to subscribers when the event fires
     * @property type
     * @type string
     */
    this.type = type;

    /**
     * The scope the the event will fire from by default.  Defaults to the window
     * obj
     * @property scope
     * @type object
     */
    this.scope = oScope || window;

    /**
     * By default all custom events are logged in the debug build, set silent
     * to true to disable logging for this event.
     * @property silent
     * @type boolean
     */
    this.silent = silent;

    /**
     * The subscribers to this event
     * @property subscribers
     * @type Subscriber[]
     */
    this.subscribers = [];

    if (!this.silent) {
    }

    // Only add subscribe events for events that are not generated by CustomEvent
    //if (oScope && (oScope.constructor != this.constructor)) {

        /*
         * Custom events provide a custom event that fires whenever there is
         * a new subscriber to the event.  This provides an opportunity to
         * handle the case where there is a non-repeating event that has
         * already fired has a new subscriber.
         *
         * type CustomEvent
         */
        //this.subscribeEvent =
                //new YAHOO.util.CustomEvent("subscribe", this, true);

    //}
};

YAHOO.util.CustomEvent.prototype = {
    /**
     * Subscribes the caller to this event
     * @method subscribe
     * @param {Function} fn       The function to execute
     * @param {Object}   obj      An object to be passed along when the event fires
     * @param {boolean}  bOverride If true, the obj passed in becomes the execution
     *                            scope of the listener
     */
    subscribe: function(fn, obj, bOverride) {
        //if (this.subscribeEvent) {
            //this.subscribeEvent.fire(fn, obj, bOverride);
        //}

        this.subscribers.push( new YAHOO.util.Subscriber(fn, obj, bOverride) );
    },

    /**
     * Unsubscribes the caller from this event
     * @method unsubscribe
     * @param {Function} fn  The function to execute
     * @param {Object}   obj An object to be passed along when the event fires
     * @return {boolean} True if the subscriber was found and detached.
     */
    unsubscribe: function(fn, obj) {
        var found = false;
        for (var i=0, len=this.subscribers.length; i<len; ++i) {
            var s = this.subscribers[i];
            if (s && s.contains(fn, obj)) {
                this._delete(i);
                found = true;
            }
        }

        return found;
    },

    /**
     * Notifies the subscribers.  The callback functions will be executed
     * from the scope specified when the event was created, and with the following
     * parameters:
     *   <pre>
     *   - The type of event
     *   - All of the arguments fire() was executed with as an array
     *   - The custom object (if any) that was passed into the subscribe() method
     *   </pre>
     * @method fire
     * @param {Array} an arbitrary set of parameters to pass to the handler
     */
    fire: function() {
        var len=this.subscribers.length;
        if (!len && this.silent) {
            return;
        }

        var args = [];

        for (var i=0; i<arguments.length; ++i) {
            args.push(arguments[i]);
        }

        if (!this.silent) {
        }

        for (i=0; i<len; ++i) {
            var s = this.subscribers[i];
            if (s) {
                if (!this.silent) {
                }
                var scope = (s.override) ? s.obj : this.scope;
                s.fn.call(scope, this.type, args, s.obj);
            }
        }
    },

    /**
     * Removes all listeners
     * @method unsubscribeAll
     */
    unsubscribeAll: function() {
        for (var i=0, len=this.subscribers.length; i<len; ++i) {
            this._delete(len - 1 - i);
        }
    },

    /**
     * @method _delete
     * @private
     */
    _delete: function(index) {
        var s = this.subscribers[index];
        if (s) {
            delete s.fn;
            delete s.obj;
        }

        // delete this.subscribers[index];
        this.subscribers.splice(index, 1);
    },

    /**
     * @method toString
     */
    toString: function() {
         return "CustomEvent: " + "'" + this.type  + "', " +
             "scope: " + this.scope;

    }
};

/////////////////////////////////////////////////////////////////////

/**
 * Stores the subscriber information to be used when the event fires.
 * @param {Function} fn       The function to execute
 * @param {Object}   obj      An object to be passed along when the event fires
 * @param {boolean}  bOverride If true, the obj passed in becomes the execution
 *                            scope of the listener
 * @class Subscriber
 * @constructor
 */
YAHOO.util.Subscriber = function(fn, obj, bOverride) {

    /**
     * The callback that will be execute when the event fires
     * @property fn
     * @type function
     */
    this.fn = fn;

    /**
     * An optional custom object that will passed to the callback when
     * the event fires
     * @property obj
     * @type object
     */
    this.obj = obj || null;

    /**
     * The default execution scope for the event listener is defined when the
     * event is created (usually the object which contains the event).
     * By setting override to true, the execution scope becomes the custom
     * object passed in by the subscriber
     * @property override
     * @type boolean
     */
    this.override = (bOverride);
};

/**
 * Returns true if the fn and obj match this objects properties.
 * Used by the unsubscribe method to match the right subscriber.
 *
 * @method contains
 * @param {Function} fn the function to execute
 * @param {Object} obj an object to be passed along when the event fires
 * @return {boolean} true if the supplied arguments match this
 *                   subscriber's signature.
 */
YAHOO.util.Subscriber.prototype.contains = function(fn, obj) {
    return (this.fn == fn && this.obj == obj);
};

/**
 * @method toString
 */
YAHOO.util.Subscriber.prototype.toString = function() {
    return "Subscriber { obj: " + (this.obj || "")  +
           ", override: " +  (this.override || "no") + " }";
};

// The first instance of Event will win if it is loaded more than once.
if (!YAHOO.util.Event) {

/**
 * 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.
 * @namespace YAHOO.util
 * @class Event
 */
    YAHOO.util.Event = function() {

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

        /**
         * Cache of wrapped listeners
         * @property listeners
         * @type array
         * @private
         */
        var listeners = [];

        /**
         * Listeners that will be attached during the onload event
         * @property delayedListeners
         * @type array
         * @private
         */
        var delayedListeners = [];

        /**
         * User-defined unload function that will be fired before all events
         * are detached
         * @property unloadListeners
         * @type array
         * @private
         */
        var unloadListeners = [];

        /**
         * Cache of DOM0 event handlers to work around issues with DOM2 events
         * in Safari
         * @property legacyEvents
         * @private
         */
        var legacyEvents = [];

        /**
         * Listener stack for DOM0 events
         * @property legacyHandlers
         * @private
         */
        var legacyHandlers = [];

        /**
         * 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
         * @private
         */
        var retryCount = 0;

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

        /**
         * Lookup table for legacy events
         * @property legacyMap
         * @private
         */
        var legacyMap = [];

        /**
         * Counter for auto id generation
         * @property counter
         * @private