base/js/BaseBuild.js

BaseBuild.js revision 64953b0596d07dbee9a9b521ed61c434ce4709b5
   /**
    * The base-build submodule provides Base.build functionality, which
    * can be used to create custom classes, by aggregating extensions onto
    * a main class.
    *
    * @module base
    * @submodule base-build
    */

   var Base = Y.Base,
       L = Y.Lang;

   /**
    * The build configuration for the Base class.
    *
    * Defines the static fields which need to be aggregated
    * when the Base class is used as the main class passed to
    * the <a href="#method_build">Base.build</a> method.
    *
    * @property _buildCfg
    * @type Object
    * @static
    * @final
    * @private
    */
   Base._buildCfg = {
       aggregates : ["ATTRS", "_PLUG", "_UNPLUG"]
   };

   /**
    * <p>
    * Builds a custom constructor function (class) from the
    * main function, and array of extension functions (classes)
    * provided. The NAME field for the constructor function is
    * defined by the first argument passed in.
    * </p>
    * <p>
    * The cfg object literal supports the following properties
    * </p>
    * <dl>
    *    <dt>dynamic &#60;boolean&#62;</dt>
    *    <dd>
    *    <p>If true (default), a completely new class
    *    is created which extends the main class, and acts as the
    *    host on which the extension classes are augmented.</p>
    *    <p>If false, the extensions classes are augmented directly to
    *    the main class, modifying the main class' prototype.</p>
    *    </dd>
    *    <dt>aggregates &#60;String[]&#62;</dt>
    *    <dd>An array of static property names, which will get aggregated
    *    on to the built class, in addition to the default properties build
    *    will always aggregate as defined by the main class' _buildCfg
    *    property.
    *    </dd>
    * </dl>
    *
    * @method build
    * @static
    * @param {Function} main The name of the new class. Used to defined the NAME property for the new class.
    * @param {Function} main The main class on which to base the built class
    * @param {Function[]} extensions The set of extension classes which will be
    * augmented/aggregated to the built class.
    * @param {Object} cfg Optional. Build configuration for the class (see description).
    * @return {Function} A custom class, created from the provided main and extension classes
    */
   Base.build = function(name, main, extensions, cfg) {

       var build = Base.build,
           builtClass = build._getClass(main, cfg),
           aggregates = build._getAggregates(main, cfg),
           dynamic = builtClass._yuibuild.dynamic,
           i, l, val, extClass;

       // Shallow isolate aggregates
       if (dynamic) {
           if (aggregates) {
               for (i = 0, l = aggregates.length; i < l; ++i) {
                   val = aggregates[i];
                   if (main.hasOwnProperty(val)) {
                       builtClass[val] = L.isArray(main[val]) ? [] : {};
                   }
               }
               Y.aggregate(builtClass, main, true, aggregates);
           }
       }

       // Augment/Aggregate
       for (i = 0, l = extensions.length; i < l; i++) {
           extClass = extensions[i];

           if (aggregates) {
               Y.aggregate(builtClass, extClass, true, aggregates);
           }

           // Old augment
           Y.mix(builtClass, extClass, true, null, 1);

           builtClass._yuibuild.exts.push(extClass);
       }

       builtClass.prototype.hasImpl = build._hasImpl;

       if (dynamic) {
           builtClass.NAME = name;
           builtClass.prototype.constructor = builtClass;
       }

       return builtClass;
   };

   Y.mix(Base.build, {

       _template: function(main) {

           function BuiltClass() {

               BuiltClass.superclass.constructor.apply(this, arguments);

               var f = BuiltClass._yuibuild.exts,
                   l = f.length,
                   i;

               for (i = 0; i < l; i++) {
                   f[i].apply(this, arguments);
               }

               return this;
           }
           Y.extend(BuiltClass, main);

           return BuiltClass;
       },

       _hasImpl : function(extClass) {
           if (this.constructor._yuibuild) {
               var f = this.constructor._yuibuild.exts,
                   l = f.length,
                   i;

               for (i = 0; i < l; i++) {
                   if (f[i] === extClass) {
                       return true;
                   }
               }
           }
           return false;
       },

       _getClass : function(main, cfg) {

          var dynamic = (cfg && false === cfg.dynamic) ? false : true,
               builtClass = (dynamic) ? Base.build._template(main) : main;

           builtClass._yuibuild = {
               id: null,
               exts : [],
               dynamic : dynamic
           };

           return builtClass;
       },

       _getAggregates : function(main, cfg) {
           var aggr = [],
               cfgAggr = (cfg && cfg.aggregates),
               c = main,
               classAggr;

           while (c && c.prototype) {
               classAggr = c._buildCfg && c._buildCfg.aggregates;
               if (classAggr) {
                   aggr = aggr.concat(classAggr);
               }
               c = c.superclass ? c.superclass.constructor : null;
           }

           if (cfgAggr) {
               aggr = aggr.concat(cfgAggr);
           }

           return aggr;
       }
   });