zentao/www/js/jquery/tablesorter/metadata.js

/*
 * Metadata - jQuery plugin for parsing metadata from elements
 *
 * Copyright (c) 2006 John Resig, Yehuda Katz, Jörn Zaefferer, Paul McLanahan
 *
 * Dual licensed under the MIT and GPL licenses:
 *   http://www.opensource.org/licenses/mit-license.php
 *   http://www.gnu.org/licenses/gpl.html
 *
 */

/**
 * Sets the type of metadata to use. Metadata is encoded in JSON, and each property
 * in the JSON will become a property of the element itself.
 *
 * There are three supported types of metadata storage:
 *
 *   attr:  Inside an attribute. The name parameter indicates *which* attribute.
 *
 *   class: Inside the class attribute, wrapped in curly braces: { }
 *
 *   elem:  Inside a child element (e.g. a script tag). The
 *          name parameter indicates *which* element.
 *
 * The metadata for an element is loaded the first time the element is accessed via jQuery.
 *
 * As a result, you can define the metadata type, use $(expr) to load the metadata into the elements
 * matched by expr, then redefine the metadata type and run another $(expr) for other elements.
 *
 * @name $.metadata.setType
 *
 * @example <p id="one" class="some_class {item_id: 1, item_label: 'Label'}">This is a p</p>
 * @before $.metadata.setType("class")
 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
 * @desc Reads metadata from the class attribute
 *
 * @example <p id="one" class="some_class" data="{item_id: 1, item_label: 'Label'}">This is a p</p>
 * @before $.metadata.setType("attr", "data")
 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
 * @desc Reads metadata from a "data" attribute
 *
 * @example <p id="one" class="some_class"><script>{item_id: 1, item_label: 'Label'}</script>This is a p</p>
 * @before $.metadata.setType("elem", "script")
 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
 * @desc Reads metadata from a nested script element
 *
 * @param String type The encoding type
 * @param String name The name of the attribute to be used to get metadata (optional)
 * @cat Plugins/Metadata
 * @descr Sets the type of encoding to be used when loading metadata for the first time
 * @type undefined
 * @see metadata()
 */

 (function($) {

	$.extend({
		metadata : {
			defaults : {
				type: 'class',
				name: 'metadata',
				cre: /({.*})/,
				single: 'metadata'
			},
			setType: function( type, name ){
				this.defaults.type = type;
				this.defaults.name = name;
			},
			get: function( elem, opts ){
				var settings = $.extend({},this.defaults,opts);
				// check for empty string in single property
				if ( !settings.single.length ) settings.single = 'metadata';

				var data = $.data(elem, settings.single);
				// returned cached data if it already exists
				if ( data ) return data;

				data = "{}";

				if ( settings.type == "class" ) {
					var m = settings.cre.exec( elem.className );
					if ( m )
						data = m[1];
				} else if ( settings.type == "elem" ) {
					if( !elem.getElementsByTagName )
						return undefined;
					var e = elem.getElementsByTagName(settings.name);
					if ( e.length )
						data = $.trim(e[0].innerHTML);
				} else if ( elem.getAttribute != undefined ) {
					var attr = elem.getAttribute( settings.name );
					if ( attr )
						data = attr;
				}

				if ( data.indexOf( '{' ) <0 )
				data = "{" + data + "}";

				data = eval("(" + data + ")");

				$.data( elem, settings.single, data );
				return data;
			}
		}
	});

	/**
	 * Returns the metadata object for the first member of the jQuery object.
	 *
	 * @name metadata
	 * @descr Returns element's metadata object
	 * @param Object opts An object contianing settings to override the defaults
	 * @type jQuery
	 * @cat Plugins/Metadata
	 */
	$.fn.metadata = function( opts ){
		return $.metadata.get( this[0], opts );
	};

})(jQuery);