jquery/src/traversing.js

var runtil = /Until$/,
	rparentsprev = /^(?:parents|prevUntil|prevAll)/,
	// Note: This RegExp should be improved, or likely pulled from Sizzle
	rmultiselector = /,/,
	slice = Array.prototype.slice;

// Implement the identical functionality for filter and not
var winnow = function( elements, qualifier, keep ) {
	if ( jQuery.isFunction( qualifier ) ) {
		return jQuery.grep(elements, function(elem, i) {
			return !!qualifier.call( elem, i ) === keep;
		});

	} else if ( qualifier.nodeType ) {
		return jQuery.grep(elements, function(elem, i) {
			return (elem === qualifier) === keep;
		});

	} else if ( typeof qualifier === "string" ) {
		var filtered = jQuery.grep(elements, function(elem) {
			return elem.nodeType === 1;
		});

		if ( isSimple.test( qualifier ) ) {
			return jQuery.filter(qualifier, filtered, !keep);
		} else {
			qualifier = jQuery.filter( qualifier, elements );
		}
	}

	return jQuery.grep(elements, function(elem, i) {
		return (jQuery.inArray( elem, qualifier ) >= 0) === keep;
	});
};

jQuery.fn.extend({
	find: function( selector ) {
		var ret = this.pushStack( "", "find", selector ), length = 0;

		for ( var i = 0, l = this.length; i < l; i++ ) {
			length = ret.length;
			jQuery.find( selector, this[i], ret );

			if ( i > 0 ) {
				// Make sure that the results are unique
				for ( var n = length; n < ret.length; n++ ) {
					for ( var r = 0; r < length; r++ ) {
						if ( ret[r] === ret[n] ) {
							ret.splice(n--, 1);
							break;
						}
					}
				}
			}
		}

		return ret;
	},

	has: function( target ) {
		var targets = jQuery( target );
		return this.filter(function() {
			for ( var i = 0, l = targets.length; i < l; i++ ) {
				if ( jQuery.contains( this, targets[i] ) ) {
					return true;
				}
			}
		});
	},

	contains: function( target ) {
		return this.has( target ).length > 0;
	},

	not: function( selector ) {
		return this.pushStack( winnow(this, selector, false), "not", selector);
	},

	filter: function( selector ) {
		return this.pushStack( winnow(this, selector, true), "filter", selector );
	},

	closest: function( selectors, context ) {
		if ( jQuery.isArray( selectors ) ) {
			var ret = [], cur = this[0], match, matches = {}, selector;

			if ( cur && selectors.length ) {
				for ( var i = 0, l = selectors.length; i < l; i++ ) {
					selector = selectors[i];

					if ( !matches[selector] ) {
						matches[selector] = jQuery.expr.match.POS.test( selector ) ? 
							jQuery( selector, context || this.context ) :
							selector;
					}
				}

				while ( cur && cur.ownerDocument && cur !== context ) {
					for ( selector in matches ) {
						match = matches[selector];

						if ( match.jquery ? match.index(cur) > -1 : jQuery(cur).is(match) ) {
							ret.push({ selector: selector, elem: cur });
							delete matches[selector];
						}
					}
					cur = cur.parentNode;
				}
			}

			return ret;
		}

		var pos = jQuery.expr.match.POS.test( selectors ) ? 
			jQuery( selectors, context || this.context ) : null;

		return this.map(function(i, cur){
			while ( cur && cur.ownerDocument && cur !== context ) {
				if ( pos ? pos.index(cur) > -1 : jQuery(cur).is(selectors) ) {
					return cur;
				}
				cur = cur.parentNode;
			}
			return null;
		});
	},

	add: function( selector, context ) {
		var set = typeof selector === "string" ?
				jQuery( selector, context || this.context ) :
				jQuery.makeArray( selector ),
			all = jQuery.merge( this.get(), set );

		return this.pushStack( set[0] && (set[0].setInterval || set[0].nodeType === 9 || (set[0].parentNode && set[0].parentNode.nodeType !== 11)) ?
			jQuery.unique( all ) :
			all );
	},

	eq: function( i ) {
		return i === -1 ?
			this.slice( i ) :
			this.slice( i, +i + 1 );
	},

	first: function() {
		return this.eq( 0 );
	},

	last: function() {
		return this.eq( -1 );
	},

	slice: function() {
		return this.pushStack( slice.apply( this, arguments ),
			"slice", slice.call(arguments).join(",") );
	},

	map: function( callback ) {
		return this.pushStack( jQuery.map(this, function(elem, i){
			return callback.call( elem, i, elem );
		}));
	},

	andSelf: function() {
		return this.add( this.prevObject );
	},

	end: function() {
		return this.prevObject || jQuery(null);
	}
});

jQuery.each({
	parent: function(elem){return elem.parentNode;},
	parents: function(elem){return jQuery.dir(elem,"parentNode");},
	parentsUntil: function(elem,i,until){return jQuery.dir(elem,"parentNode",until);},
	next: function(elem){return jQuery.nth(elem,2,"nextSibling");},
	prev: function(elem){return jQuery.nth(elem,2,"previousSibling");},
	nextAll: function(elem){return jQuery.dir(elem,"nextSibling");},
	prevAll: function(elem){return jQuery.dir(elem,"previousSibling");},
	nextUntil: function(elem,i,until){return jQuery.dir(elem,"nextSibling",until);},
	prevUntil: function(elem,i,until){return jQuery.dir(elem,"previousSibling",until);},
	siblings: function(elem){return jQuery.sibling(elem.parentNode.firstChild,elem);},
	children: function(elem){return jQuery.sibling(elem.firstChild);},
	contents: function(elem){return jQuery.nodeName(elem,"iframe")?elem.contentDocument||elem.contentWindow.document:jQuery.makeArray(elem.childNodes);}
}, function(name, fn){
	jQuery.fn[ name ] = function( until, selector ) {
		var ret = jQuery.map( this, fn, until );
		
		if ( !runtil.test( name ) ) {
			selector = until;
		}

		if ( selector && typeof selector === "string" ) {
			ret = jQuery.filter( selector, ret );
		}

		ret = this.length > 1 ? jQuery.unique( ret ) : ret;

		if ( (this.length > 1 || rmultiselector.test( selector )) && rparentsprev.test( name ) ) {
			ret = ret.reverse();
		}

		return this.pushStack( ret, name, slice.call(arguments).join(",") );
	};
});

jQuery.extend({
	filter: function( expr, elems, not ) {
		if ( not ) {
			expr = ":not(" + expr + ")";
		}

		return jQuery.find.matches(expr, elems);
	},
	
	dir: function( elem, dir, until ) {
		var matched = [], cur = elem[dir];
		while ( cur && cur.nodeType !== 9 && (until === undefined || !jQuery( cur ).is( until )) ) {
			if ( cur.nodeType === 1 ) {
				matched.push( cur );
			}
			cur = cur[dir];
		}
		return matched;
	},

	nth: function( cur, result, dir, elem ) {
		result = result || 1;
		var num = 0;

		for ( ; cur; cur = cur[dir] ) {
			if ( cur.nodeType === 1 && ++num === result ) {
				break;
			}
		}

		return cur;
	},

	sibling: function( n, elem ) {
		var r = [];

		for ( ; n; n = n.nextSibling ) {
			if ( n.nodeType === 1 && n !== elem ) {
				r.push( n );
			}
		}

		return r;
	}
});