Cleans up and simplifies code shared by ajaxPrefilter and ajaxTransport....

Cleans up and simplifies code shared by ajaxPrefilter and ajaxTransport. Removes chainability of ajaxSetup, ajaxPrefilter and ajaxTransport. Also makes sure context is handled properly by ajaxSetup (unit test added).

src/ajax.js

@@ -161,7 +161,9 @@ jQuery.extend({
 
 	ajaxSetup: function( settings ) {
 		jQuery.extend( true, jQuery.ajaxSettings, settings );
-		return this;
+		if ( settings.context ) {
+			jQuery.ajaxSettings.context = settings.context;
+		}
 	},
 
 	ajaxSettings: {
@@ -278,6 +280,14 @@ jQuery.extend({
 
 	},
 
+	ajaxPrefilter: function( a , b ) {
+		ajaxPrefilterOrTransport( "prefilters" , a , b );
+	},
+
+	ajaxTransport: function( a , b ) {
+		return ajaxPrefilterOrTransport( "transports" , a , b );
+	},
+
 	// Main method
 	ajax: function( url , options ) {
 
@@ -299,7 +309,11 @@ jQuery.extend({
 			jQuery_lastModified = jQuery.lastModified,
 			jQuery_etag = jQuery.etag,
 			// Callbacks contexts
-			callbackContext = options.context || s.context || s,
+			// We force the original context if it exists
+			// or take it from jQuery.ajaxSettings otherwise
+			// (plain objects used as context get extended)
+			callbackContext =
+				( s.context = ( "context" in options ? options : jQuery.ajaxSettings ).context ) || s,
 			globalEventContext = callbackContext === s ? jQuery.event : jQuery( callbackContext ),
 			// Deferreds
 			deferred = jQuery.Deferred(),
@@ -373,10 +387,6 @@ jQuery.extend({
 				}
 			};
 
-		// We force the original context
-		// (plain objects used as context get extended)
-		s.context = options.context;
-
 		// Callback for when everything is done
 		// It is defined here because jslint complains if it is declared
 		// at the end of the function (which would be more logical and readable)
@@ -850,126 +860,97 @@ jQuery.extend({
 
 });
 
-//Execute or select from functions in a given structure of options
-function ajax_selectOrExecute( structure , s , options ) {
+// Base function for both ajaxPrefilter and ajaxTransport
+function ajaxPrefilterOrTransport( arg0 , arg1 , arg2 ) {
 
-	var dataTypes = s.dataTypes,
-		transportDataType,
-		list,
-		selected,
+	var type = jQuery.type( arg1 ),
+		structure = jQuery.ajaxSettings[ arg0 ],
 		i,
-		length,
-		checked = {},
-		flag,
-		noSelect = structure !== "transports";
-
-	function initSearch( dataType ) {
-
-		flag = transportDataType !== dataType && ! checked[ dataType ];
-
-		if ( flag ) {
-
-			checked[ dataType ] = 1;
-			transportDataType = dataType;
-			list = s[ structure ][ dataType ];
-			i = -1;
-			length = list ? list.length : 0 ;
-		}
-
-		return flag;
+		length;
+
+	// We have an options map so we have to inspect the structure
+	if ( type === "object" ) {
+
+		var options = arg1,
+			originalOptions = arg2,
+			// When dealing with prefilters, we execute only
+			// (no selection so we never stop when a function
+			// returns a non-falsy, non-string value)
+			executeOnly = ( arg0 === "prefilters" ),
+			inspect = function( dataType, tested ) {
+
+				if ( ! tested[ dataType ] ) {
+
+					tested[ dataType ] = true;
+
+					var list = structure[ dataType ],
+						selected;
+
+					for( i = 0, length = list ? list.length : 0 ; ( executeOnly || ! selected ) && i < length ; i++ ) {
+						selected = list[ i ]( options , originalOptions );
+						// If we got redirected to a different dataType,
+						// we add it and switch to the corresponding list
+						if ( typeof( selected ) === "string" && selected !== dataType ) {
+							options.dataTypes.unshift( selected );
+							selected = inspect( selected , tested );
+							// We always break in order not to continue
+							// to iterate in previous list
+							break;
 						}
-
-	initSearch( dataTypes[ 0 ] );
-
-	for ( i = 0 ; ( noSelect || ! selected ) && i <= length ; i++ ) {
-
-		if ( i === length ) {
-
-			initSearch( "*" );
-
-		} else {
-
-			selected = list[ i ]( s , options );
-
-			// If we got redirected to another dataType
-			// Search there (if not in progress or already tried)
-			if ( typeof( selected ) === "string" &&
-				initSearch( selected ) ) {
-
-				dataTypes.unshift( selected );
-				selected = 0;
 					}
+					// If we're only executing or nothing was selected
+					// we try the catchall dataType
+					if ( executeOnly || ! selected ) {
+						selected = inspect( "*" , tested );
 					}
+					// This will be ignored by ajaxPrefilter
+					// so it's safe to return no matter what
+					return selected;
 				}
 
-	return noSelect ? jQuery : selected;
-}
-
-// Add an element to one of the structures in ajaxSettings
-function ajax_addElement( structure , args ) {
-
-	var i,
-		start = 0,
-		length = args.length,
-		dataTypes = [ "*" ],
-		dLength = 1,
-		dataType,
-		functors = [],
-		first,
-		append,
-		list;
-
-	if ( length ) {
-
-		first = jQuery.type( args[ 0 ] );
-
-		if ( first === "object" ) {
-			return ajax_selectOrExecute( structure , args[ 0 ] , args[ 1 ] );
-		}
+			};
 
-		structure = jQuery.ajaxSettings[ structure ];
+		// Start inspection with current transport dataType
+		return inspect( options.dataTypes[ 0 ] , {} );
 
-		if ( first !== "function" ) {
+	} else {
 
-			dataTypes = args[ 0 ].toLowerCase().split(/\s+/);
-			dLength = dataTypes.length;
-			start = 1;
+		// We're requested to add to the structure
+		// Signature is ( dataTypeExpression , function )
+		// with dataTypeExpression being optional and
+		// defaulting to catchAll (*)
+		type = type === "function";
 
+		if ( type ) {
+			arg2 = arg1;
+			arg1 = undefined;
 		}
+		arg1 = arg1 || "*";
 
-		if ( dLength && start < length ) {
-
-			functors = sliceFunc.call( args , start );
+		// We control that the second argument is really a function
+		if ( type || jQuery.isFunction( arg2 ) ) {
 
-			for( i = 0 ; i < dLength ; i++ ) {
+			var dataTypes = arg1.split( /\s+/ ),
+				functor = arg2,
+				dataType,
+				list,
+				placeBefore;
 
+			// For each dataType in the dataTypeExpression
+			for( i = 0 , length = dataTypes.length ; i < length ; i++ ) {
 				dataType = dataTypes[ i ];
-
-				first = /^\+/.test( dataType );
-
-				if (first) {
-					dataType = dataType.substr(1);
+				// We control if we're asked to add before
+				// any existing element
+				placeBefore = /^\+/.test( dataType );
+				if ( placeBefore ) {
+					dataType = dataType.substr( 1 );
 				}
-
-				if ( dataType !== "" ) {
-
-					append = Array.prototype[ first ? "unshift" : "push" ];
 				list = structure[ dataType ] = structure[ dataType ] || [];
-					append.apply( list , functors );
-				}
+				// then we add to the structure accordingly
+				list[ placeBefore ? "unshift" : "push" ]( functor );
 			}
 		}
 	}
-
-	return jQuery;
 }
 
-// Install prefilter & transport methods
-jQuery.each( [ "Prefilter" , "Transport" ] , function( _ , name ) {
-	_ = name.toLowerCase() + "s";
-	jQuery[ "ajax" + name ] = function() {
-		return ajax_addElement( _ , arguments );
-	};
-} );
-
 })( jQuery );

src/ajax/jsonp.js

@@ -9,10 +9,11 @@ jQuery.ajaxSetup({
 	jsonpCallback: function() {
 		return "jsonp" + jsc++;
 	}
+});
 
 // Detect, normalize options and install callbacks for jsonp requests
 // (dataIsString is used internally)
-}).ajaxPrefilter("json jsonp", function(s, originalSettings, dataIsString) {
+jQuery.ajaxPrefilter("json jsonp", function(s, originalSettings, dataIsString) {
 
 	dataIsString = ( typeof(s.data) === "string" );
 

src/ajax/script.js

@@ -14,9 +14,10 @@ jQuery.ajaxSetup({
 	converters: {
 		"text script": jQuery.globalEval
 	}
+});
 
 // Handle cache's special case and global
-}).ajaxPrefilter("script", function(s) {
+jQuery.ajaxPrefilter("script", function(s) {
 
 	if ( s.cache === undefined ) {
 		s.cache = false;
@@ -26,9 +27,10 @@ jQuery.ajaxSetup({
 		s.type = "GET";
 		s.global = false;
 	}
+});
 
 // Bind script tag hack transport
-}).ajaxTransport("script", function(s) {
+jQuery.ajaxTransport("script", function(s) {
 
 	// This transport only deals with cross domain requests
 	if ( s.crossDomain ) {

test/unit/ajax.js

@@ -599,6 +599,47 @@ test("jQuery.ajax context modification", function() {
 	equals( obj.test, "foo", "Make sure the original object is maintained." );
 });
 
+test("jQuery.ajax context modification through ajaxSetup", function() {
+	expect(4);
+
+	stop();
+
+	var obj = {};
+
+	jQuery.ajaxSetup({
+		context: obj
+	});
+
+	strictEqual( jQuery.ajaxSettings.context, obj, "Make sure the context is properly set in ajaxSettings." );
+
+	jQuery.ajax({
+		url: url("data/name.html"),
+		complete: function() {
+			strictEqual( this, obj, "Make sure the original object is maintained." );
+			jQuery.ajax({
+				url: url("data/name.html"),
+				context: {},
+				complete: function() {
+					ok( this !== obj, "Make sure overidding context is possible." );
+					jQuery.ajaxSetup({
+						context: false
+					});
+					jQuery.ajax({
+						url: url("data/name.html"),
+						beforeSend: function(){
+							this.test = "foo2";
+						},
+						complete: function() {
+							ok( this !== obj, "Make sure unsetting context is possible." );
+							start();
+						}
+					});
+				}
+			});
+		}
+	});
+});
+
 test("jQuery.ajax() - disabled globals", function() {
 	expect( 3 );
 	stop();