Yahoo! UI Library

/**
 * The YAHOO object is the single global object used by YUI Library.  It
 * contains utility function for setting up namespaces, inheritance, and
 * logging.  YAHOO.util, YAHOO.widget, and YAHOO.example are namespaces
 * created automatically for and used by the library.
 * @module yahoo
 * @title  YAHOO Global
 */

/**
 * YAHOO_config is not included part of the library.  Instead it is an object
 * that can be defined by the implementer immediately before including the
 * YUI library.  The properties included in this object will be used to
 * configure global properties needed as soon as the library begins to load.
 * @class YAHOO_config
 * @static
 */

/**
 * A reference to a function that will be executed every time a YAHOO module
 * is loaded.  As parameter, this function will receive the version
 * information for the module. See <a href="YAHOO.env.html#getVersion">
 * YAHOO.env.getVersion</a> for the description of the version data structure.
 * @property listener
 * @static
 */
if (typeof YAHOO == "undefined") {
    /**
     * The YAHOO global namespace object.  If YAHOO is already defined, the
     * existing YAHOO object will not be overwritten so that defined
     * namespaces are preserved.
     * @class YAHOO
     * @static
     */
    var YAHOO = {};
}

/**
 * Returns the namespace specified and creates it if it doesn't exist
 * <pre>
 * YAHOO.namespace("property.package");
 * YAHOO.namespace("YAHOO.property.package");
 * </pre>
 * Either of the above would create YAHOO.property, then
 * YAHOO.property.package
 *
 * Be careful when naming packages. Reserved words may work in some browsers
 * and not others. For instance, the following will fail in Safari:
 * <pre>
 * YAHOO.namespace("really.long.nested.namespace");
 * </pre>
 * This fails because "long" is a future reserved word in ECMAScript
 *
 * @method namespace
 * @static
 * @param  {String*} arguments 1-n namespaces to create 
 * @return {Object}  A reference to the last namespace object created
 */
YAHOO.namespace = function() {
    var a=arguments, o=null, i, j, d;
    for (i=0; i<a.length; i=i+1) {
        d=a[i].split(".");
        o=YAHOO;

        // YAHOO is implied, so it is ignored if it is included
        for (j=(d[0] == "YAHOO") ? 1 : 0; j<d.length; j=j+1) {
            o[d[j]]=o[d[j]] || {};
            o=o[d[j]];
        }
    }

    return o;
};

/**
 * Uses YAHOO.widget.Logger to output a log message, if the widget is
 * available.
 *
 * @method log
 * @static
 * @param  {String}  msg  The message to log.
 * @param  {String}  cat  The log category for the message.  Default
 *                        categories are "info", "warn", "error", time".
 *                        Custom categories can be used as well. (opt)
 * @param  {String}  src  The source of the the message (opt)
 * @return {Boolean}      True if the log operation was successful.
 */
YAHOO.log = function(msg, cat, src) {
    var l=YAHOO.widget.Logger;
    if(l && l.log) {
        return l.log(msg, cat, src);
    } else {
        return false;
    }
};


/**
 * Initializes the global by creating the default namespaces and applying
 * any new configuration information that is detected.
 * @method init
 * @static
 */
YAHOO.init = function() {
    this.namespace("util", "widget", "example");
    if (typeof YAHOO_config != "undefined") {
        var l=YAHOO_config.listener,ls=YAHOO.env.listeners,unique=true,i;
        if (l) {
            // if YAHOO is loaded multiple times we need to check to see if
            // this is a new config object.  If it is, add the new component
            // load listener to the stack
            for (i=0;i<ls.length;i=i+1) {
                if (ls[i]==l) {
                    unique=false;
                    break;
                }
            }
            if (unique) {
                ls.push(l);
            }
        }
    }
};

/**
 * Registers a module with the YAHOO object
 * @method register
 * @static
 * @param {String}   name    the name of the module (event, slider, etc)
 * @param {Function} mainClass a reference to class in the module.  This
 *                             class will be tagged with the version info
 *                             so that it will be possible to identify the
 *                             version that is in use when multiple versions
 *                             have loaded
 * @param {Object}   data      metadata object for the module.  Currently it
 *                             is expected to contain a "version" property
 *                             and a "build" property at minimum.
 */
YAHOO.register = function(name, mainClass, data) {
    var mods = YAHOO.env.modules;
    if (!mods[name]) {
        mods[name] = { versions:[], builds:[] };
    }
    var m=mods[name],v=data.version,b=data.build,ls=YAHOO.env.listeners;
    m.name = name;
    m.version = v;
    m.build = b;
    m.versions.push(v);
    m.builds.push(b);
    m.mainClass = mainClass;
    // fire the module load listeners
    for (var i=0;i<ls.length;i=i+1) {
        ls[i](m);
    }
    // label the main class
    if (mainClass) {
        mainClass.VERSION = v;
        mainClass.BUILD = b;
    } else {
        YAHOO.log("mainClass is undefined for module " + name, "warn");
    }
};

/**
 * YAHOO.env is used to keep track of what is known about the YUI library and
 * the browsing environment
 * @class YAHOO.env
 * @type Object
 * @static
 */
YAHOO.env = YAHOO.env || {
    /**
     * Keeps the version info for all YUI modules that have reported themselves
     * @property modules
     * @type Object[]
     */
    modules: [],
    
    /**
     * List of functions that should be executed every time a YUI module
     * reports itself.
     * @property listeners
     * @type Function[]
     */
    listeners: [],
    
    /**
     * Returns the version data for the specified module:
     *      <dl>
     *      <dt>name:</dt>      <dd>The name of the module</dd>
     *      <dt>version:</dt>   <dd>The version in use</dd>
     *      <dt>build:</dt>     <dd>The build number in use</dd>
     *      <dt>versions:</dt>  <dd>All versions that were registered</dd>
     *      <dt>builds:</dt>    <dd>All builds that were registered.</dd>
     *      <dt>mainClass:</dt> <dd>An object that was was stamped with the
     *                 current version and build. If 
     *                 mainClass.VERSION != version or mainClass.BUILD != build,
     *                 multiple versions of pieces of the library have been
     *                 loaded, potentially causing issues.</dd>
     *       </dl>
     *
     * @method getVersion
     * @static
     * @param {String}  name the name of the module (event, slider, etc)
     * @return {Object} The version info
     */
    getVersion: function(name) {
        return YAHOO.env.modules[name] || null;
    }
};

/**
 * Provides the language utilites and extensions used by the library
 * @class YAHOO.lang
 */
YAHOO.lang = {
    /**
     * Determines whether or not the provided object is an array
     * @method isArray
     * @param {any} obj The object being testing
     * @return Boolean
     */
    isArray: function(obj) { // frames lose type, so test constructor string
        if (obj.constructor && obj.constructor.toString().indexOf('Array') > -1) {
            return true;
        } else {
            return YAHOO.lang.isObject(obj) && obj.constructor == Array;
        }
    },

    /**
     * Determines whether or not the provided object is a boolean
     * @method isBoolean
     * @param {any} obj The object being testing
     * @return Boolean
     */
    isBoolean: function(obj) {
        return typeof obj == 'boolean';
    },
    
    /**
     * Determines whether or not the provided object is a function
     * @method isFunction
     * @param {any} obj The object being testing
     * @return Boolean
     */
    isFunction: function(obj) {
        return typeof obj == 'function';
    },
        
    /**
     * Determines whether or not the provided object is null
     * @method isNull
     * @param {any} obj The object being testing
     * @return Boolean
     */
    isNull: function(obj) {
        return obj === null;
    },
        
    /**
     * Determines whether or not the provided object is a legal number
     * @method isNumber
     * @param {any} obj The object being testing
     * @return Boolean
     */
    isNumber: function(obj) {
        return typeof obj == 'number' && isFinite(obj);
    },
      
    /**
     * Determines whether or not the provided object is of type object
     * or function
     * @method isObject
     * @param {any} obj The object being testing
     * @return Boolean
     */  
    isObject: function(obj) {
        return typeof obj == 'object' || YAHOO.lang.isFunction(obj);
    },
        
    /**
     * Determines whether or not the provided object is a string
     * @method isString
     * @param {any} obj The object being testing
     * @return Boolean
     */
    isString: function(obj) {
        return typeof obj == 'string';
    },
        
    /**
     * Determines whether or not the provided object is undefined
     * @method isUndefined
     * @param {any} obj The object being testing
     * @return Boolean
     */
    isUndefined: function(obj) {
        return typeof obj == 'undefined';
    },
    
    /**
     * Determines whether or not the property was added
     * to the object instance.  Returns false if the property is not present
     * in the object, or was inherited from the prototype.
     * This abstraction is provided to enable hasOwnProperty for Safari 1.3.x.
     * There is a discrepancy between YAHOO.lang.hasOwnProperty and
     * Object.prototype.hasOwnProperty when the property is a primitive added to
     * both the instance AND prototype with the same value:
     * <pre>
     * var A = function() {};
     * A.prototype.foo = 'foo';
     * var a = new A();
     * a.foo = 'foo';
     * alert(a.hasOwnProperty('foo')); // true
     * alert(YAHOO.lang.hasOwnProperty(a, 'foo')); // false when using fallback
     * </pre>
     * @method hasOwnProperty
     * @param {any} obj The object being testing
     * @return Boolean
     */
    hasOwnProperty: function(obj, prop) {
        if (Object.prototype.hasOwnProperty) {
            return obj.hasOwnProperty(prop);
        }
        
        return !YAHOO.lang.isUndefined(obj[prop]) && 
                obj.constructor.prototype[prop] !== obj[prop];
    },
        
    /**
     * Utility to set up the prototype, constructor and superclass properties to
     * support an inheritance strategy that can chain constructors and methods.
     *
     * @method extend
     * @static
     * @param {Function} subc   the object to modify
     * @param {Function} superc the object to inherit
     * @param {Object} overrides  additional properties/methods to add to the
     *                              subclass prototype.  These will override the
     *                              matching items obtained from the superclass 
     *                              if present.
     */
    extend: function(subc, superc, overrides) {
        var F = function() {};
        F.prototype=superc.prototype;
        subc.prototype=new F();
        subc.prototype.constructor=subc;
        subc.superclass=superc.prototype;
        if (superc.prototype.constructor == Object.prototype.constructor) {
            superc.prototype.constructor=superc;
        }
    
        if (overrides) {
            for (var i in overrides) {
                subc.prototype[i]=overrides[i];
            }
        }
    },
    
    /**
     * Applies all prototype properties in the supplier to the receiver if the
     * receiver does not have these properties yet.  Optionally, one or more
     * methods/properties can be specified (as additional parameters).  This
     * option will overwrite the property if receiver has it already.
     *
     * @method augment
     * @static
     * @param {Function} r  the object to receive the augmentation
     * @param {Function} s  the object that supplies the properties to augment
     * @param {String*}  arguments zero or more properties methods to augment the
     *                             receiver with.  If none specified, everything
     *                             in the supplier will be used unless it would
     *                             overwrite an existing property in the receiver
     */
    augment: function(r, s) {
        var rp=r.prototype, sp=s.prototype, a=arguments, i, p;
        if (a[2]) {
            for (i=2; i<a.length; i=i+1) {
                rp[a[i]] = sp[a[i]];
            }
        } else {
            for (p in sp) { 
                if (!rp[p]) {
                    rp[p] = sp[p];
                }
            }
        }
    }
};

YAHOO.init();

/*
 * An alias for <a href="YAHOO.lang.html">YAHOO.lang</a>
 * @class YAHOO.util.Lang
 */
YAHOO.util.Lang = YAHOO.lang;

/**
 * An alias for <a href="YAHOO.lang.html#augment">YAHOO.lang.augment</a>
 * @for YAHOO
 * @method augment
 * @static
 * @param {Function} r  the object to receive the augmentation
 * @param {Function} s  the object that supplies the properties to augment
 * @param {String*}  arguments zero or more properties methods to augment the
 *                             receiver with.  If none specified, everything
 *                             in the supplier will be used unless it would
 *                             overwrite an existing property in the receiver
 */
YAHOO.augment = YAHOO.lang.augment;
       
/**
 * An alias for <a href="YAHOO.lang.html#extend">YAHOO.lang.extend</a>
 * @method extend
 * @static
 * @param {Function} subc   the object to modify
 * @param {Function} superc the object to inherit
 * @param {Object} overrides  additional properties/methods to add to the
 *                              subclass prototype.  These will override the
 *                              matching items obtained from the superclass 
 *                              if present.
 */
YAHOO.extend = YAHOO.lang.extend;