Cut down on some more function calls for jQuery(...). Everything points back...

Cut down on some more function calls for jQuery(...). Everything points back to the same root jQuery(document) object now. Going towards ticket #4240.

src/core.js

@@ -10,7 +10,9 @@ var
 
 	jQuery = window.jQuery = window.$ = function( selector, context ) {
 		// The jQuery object is actually just the init constructor 'enhanced'
-		return new jQuery.fn.init( selector, context );
+		return selector === undefined ?
+			rootjQuery :
+			new jQuery.fn.init( selector, context );
 	},
 
 	// A simple way to check for HTML strings or ID strings
@@ -21,15 +23,9 @@ var
 
 jQuery.fn = jQuery.prototype = {
 	init: function( selector, context ) {
-		// Make sure that a selection was provided
-		if ( selector === undefined ) {
-			selector = document;
-		}
-
-		// Handle "", null
+		// Handle $("") or $(null)
 		if ( !selector ) {
 			this.length = 0;
-			this.context = document;
 			return this;
 		}
 
@@ -60,32 +56,30 @@ jQuery.fn = jQuery.prototype = {
 					// Handle the case where IE and Opera return items
 					// by name instead of ID
 					if ( elem && elem.id != match[3] ) {
-						return jQuery().find( selector );
+						return rootjQuery.find( selector );
 					}
 
 					// Otherwise, we inject the element directly into the jQuery object
-					var ret = jQuery( elem || [] );
+					var ret = jQuery( elem || null );
 					ret.context = document;
 					ret.selector = selector;
 					return ret;
 				}
 
-			// HANDLE: $(expr, [context])
-			// (which is just equivalent to: $(content).find(expr)
-			} else if ( !context || context.nodeType ) {
-				this[0] = context || document;
-				this.length = 1;
-				this.context = context;
-				return this.find( selector );
+			// HANDLE: $(expr, $(...))
+			} else if ( !context || context.jquery ) {
+				return (context || rootjQuery).find( selector );
 
+			// HANDLE: $(expr, context)
+			// (which is just equivalent to: $(content).find(expr)
 			} else {
-				return (context.jquery ? context : jQuery( context )).find( selector );
+				return jQuery( context ).find( selector );
 			}
 
 		// HANDLE: $(function)
 		// Shortcut for document ready
 		} else if ( jQuery.isFunction( selector ) ) {
-			return jQuery( document ).ready( selector );
+			return rootjQuery.ready( selector );
 		}
 
 		// Make sure that old selector state is passed along
@@ -126,7 +120,7 @@ jQuery.fn = jQuery.prototype = {
 	// (returning the new matched element set)
 	pushStack: function( elems, name, selector ) {
 		// Build a new jQuery matched element set
-		var ret = jQuery( elems );
+		var ret = jQuery( elems || null );
 
 		// Add the old object onto the stack (as a reference)
 		ret.prevObject = this;
@@ -282,7 +276,7 @@ jQuery.fn = jQuery.prototype = {
 	},
 
 	end: function() {
-		return this.prevObject || jQuery( [] );
+		return this.prevObject || jQuery(null);
 	},
 
 	// For internal use only.
@@ -1164,6 +1158,9 @@ jQuery.extend({
 	}
 });
 
+// All jQuery objects should point back to these
+var rootjQuery = jQuery(document);
+
 // Use of jQuery.browser is deprecated.
 // It's included for backwards compatibility and plugins,
 // although they should work to migrate away.