128 lines
3.0 KiB
JavaScript
128 lines
3.0 KiB
JavaScript
/**
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* Contains basic inheritance mechanism
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*
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* Copyright (C) 2010 Mike Gerwitz
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* @author Mike Gerwitz
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* @package core
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*/
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/**
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* Default class implementation
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*
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* @return undefined
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*/
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var Class = function()
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{
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};
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/**
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* Copies properties to the destination object
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*
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* The destination object is directly modified.
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*
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* @param {Object} props properties to copy
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* @param {Object} dest destination object
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*
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* @return undefined
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*/
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var prop_copy = function( props, dest )
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{
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// copy each of the properties to the destination object
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for ( property in props )
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{
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dest[ property ] = props[ property ];
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}
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}
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/**
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* Mimics class inheritance
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*
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* This method will mimic inheritance by setting up the prototype with the
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* provided base class (or, by default, Class) and copying the additional
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* properties atop of it.
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*
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* The class to inherit from (the first argument) is optional. If omitted, the
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* first argument will be considered to be the properties list.
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*
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* @return {Object} extended class
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*/
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var extend = function()
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{
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var args = Array.prototype.slice.call( arguments ),
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props = args.pop() || {},
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base = args.pop() || Class,
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prototype = new base(),
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new_class = function()
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{
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if ( this.__construct instanceof Function )
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{
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this.__construct.apply( this, arguments );
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}
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};
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// copy the given properties into the new prototype
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prop_copy( props, prototype );
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// set up the new class
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new_class.prototype = prototype;
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new_class.constructor = new_class;
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return new_class;
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}
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/**
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* Creates a class, inheriting either from the provided base class or the
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* default base class
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*
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* @param {Object} base object to extend (extends Class by default)
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*
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* @return {Object} extended class
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*/
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exports.extend = function( base )
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{
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return extend.apply( this, arguments );
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}
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/**
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* Shorthand for extending classes
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*
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* This method can be invoked on the object, rater than having to call
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* Class.extend( this ).
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*
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* @param {Object} props properties to add to extended class
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*
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* @return {Object} extended class
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*/
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Object.defineProperty( Class, 'extend',
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{
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value: function( props )
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{
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return extend( this, props );
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},
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enumerable: false,
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writable: false,
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configurable: false,
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} );
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