jquery/src/data.js

var expando = "jQuery" + now(), uuid = 0, windowData = {};
var emptyObject = {};

jQuery.extend({
	cache: {},
	
	expando:expando,

	data: function( elem, name, data ) {
		elem = elem == window ?
			windowData :
			elem;

		var id = elem[ expando ], cache = jQuery.cache, thisCache;

		// Handle the case where there's no name immediately
		if ( !name && !id ) {
			return null;
		}

		// Compute a unique ID for the element
		if ( !id ) { 
			id = ++uuid;
		}

		// Avoid generating a new cache unless none exists and we
		// want to manipulate it.
		if ( cache[ id ] ) {
			thisCache = cache[ id ];
		} else if ( typeof data === "undefined" ) {
			thisCache = emptyObject;
		} else {
			thisCache = cache[ id ] = {};
		}
		
		// Prevent overriding the named cache with undefined values
		if ( data !== undefined ) {
			elem[ expando ] = id;
			thisCache[ name ] = data;
		}
		
		return name ? thisCache[ name ] : thisCache;
	},

	removeData: function( elem, name ) {
		elem = elem == window ?
			windowData :
			elem;

		var id = elem[ expando ], cache = jQuery.cache, thisCache = cache[ id ];

		// If we want to remove a specific section of the element's data
		if ( name ) {
			if ( thisCache ) {
				// Remove the section of cache data
				delete thisCache[ name ];

				// If we've removed all the data, remove the element's cache
				if ( jQuery.isEmptyObject(thisCache) ) {
					jQuery.removeData( elem );
				}
			}

		// Otherwise, we want to remove all of the element's data
		} else {
			// Clean up the element expando
			try {
				delete elem[ expando ];
			} catch( e ) {
				// IE has trouble directly removing the expando
				// but it's ok with using removeAttribute
				if ( elem.removeAttribute ) {
					elem.removeAttribute( expando );
				}
			}

			// Completely remove the data cache
			delete cache[ id ];
		}
	},
	
	queue: function( elem, type, data ) {
		if( !elem ) return;

		type = (type || "fx") + "queue";
		var q = jQuery.data( elem, type );

		// Speed up dequeue by getting out quickly if this is just a lookup
		if( !data ) return q || [];

		if ( !q || jQuery.isArray(data) )
			q = jQuery.data( elem, type, jQuery.makeArray(data) );
		else
			q.push( data );

		return q;
	},

	dequeue: function( elem, type ){
		type = type || "fx";

		var queue = jQuery.queue( elem, type ), fn = queue.shift();

		// If the fx queue is dequeued, always remove the progress sentinel
		if( fn === "inprogress" ) fn = queue.shift();

		if( fn ) {
			// Add a progress sentinel to prevent the fx queue from being
			// automatically dequeued
			if( type == "fx" ) queue.unshift("inprogress");

			fn.call(elem, function() { jQuery.dequeue(elem, type); });
		}
	}
});

jQuery.fn.extend({
	data: function( key, value ){
		if ( typeof key === "undefined" && this.length ) {
			return jQuery.data( this[0] );
		}

		var parts = key.split(".");
		parts[1] = parts[1] ? "." + parts[1] : "";

		if ( value === undefined ) {
			var data = this.triggerHandler("getData" + parts[1] + "!", [parts[0]]);

			if ( data === undefined && this.length )
				data = jQuery.data( this[0], key );

			return data === undefined && parts[1] ?
				this.data( parts[0] ) :
				data;
		} else
			return this.trigger("setData" + parts[1] + "!", [parts[0], value]).each(function(){
				jQuery.data( this, key, value );
			});
	},

	removeData: function( key ){
		return this.each(function(){
			jQuery.removeData( this, key );
		});
	},
	queue: function(type, data){
		if ( typeof type !== "string" ) {
			data = type;
			type = "fx";
		}

		if ( data === undefined )
			return jQuery.queue( this[0], type );

		return this.each(function(i, elem){
			var queue = jQuery.queue( this, type, data );

			if( type == "fx" && queue[0] !== "inprogress" )
				jQuery.dequeue( this, type )
		});
	},
	dequeue: function(type){
		return this.each(function(){
			jQuery.dequeue( this, type );
		});
	},
	clearQueue: function(type){
		return this.queue( type || "fx", [] );
	}
});