better, more maintainable version of the prefilters execution and transport selection

diff --git a/src/ajax.js b/src/ajax.js
index 2be654a85f4e83302ea70ab51c06b106f661e43d..394c84e66e216829ee6d1ea886c611b23eff5d89 100644 (file)
--- a/src/ajax.js
+++ b/src/ajax.js
@@ -88,43 +88,28 @@ function addToPrefiltersOrTransports( structure ) {
 }
 
 // Base inspection function for prefilters and transports
-function inspectPrefiltersOrTransports( structure, options, originalOptions, jqXHR,
-               dataType /* internal */, inspected /* internal */ ) {
-
-       dataType = dataType || options.dataTypes[ 0 ];
-       inspected = inspected || {};
-
-       inspected[ dataType ] = true;
-
-       var selection,
-               list = structure[ dataType ],
-               i = 0,
-               length = list ? list.length : 0,
-               executeOnly = ( structure === prefilters );
-
-       for ( ; i < length && ( executeOnly || !selection ); i++ ) {
-               selection = list[ i ]( options, originalOptions, jqXHR );
-               // If we got redirected to another dataType
-               // we try there if executing only and not done already
-               if ( typeof selection === "string" ) {
-                       if ( !executeOnly || inspected[ selection ] ) {
-                               selection = undefined;
-                       } else {
-                               options.dataTypes.unshift( selection );
-                               selection = inspectPrefiltersOrTransports(
-                                               structure, options, originalOptions, jqXHR, selection, inspected );
+function inspectPrefiltersOrTransports( structure, options, originalOptions, jqXHR ) {
+
+       var inspected = {},
+               seekingTransport = ( structure === transports );
+
+       function inspect( dataType ) {
+               var selected;
+               inspected[ dataType ] = true;
+               jQuery.each( structure[ dataType ] || [], function( _, prefilterOrFactory ) {
+                       var dataTypeOrTransport = prefilterOrFactory( options, originalOptions, jqXHR );
+                       if( typeof dataTypeOrTransport === "string" && !seekingTransport && !inspected[ dataTypeOrTransport ] ) {
+                               options.dataTypes.unshift( dataTypeOrTransport );
+                               inspect( dataTypeOrTransport );
+                               return false;
+                       } else if ( seekingTransport ) {
+                               return !( selected = dataTypeOrTransport );
                        }
-               }
-       }
-       // If we're only executing or nothing was selected
-       // we try the catchall dataType if not done already
-       if ( ( executeOnly || !selection ) && !inspected[ "*" ] ) {
-               selection = inspectPrefiltersOrTransports(
-                               structure, options, originalOptions, jqXHR, "*", inspected );
+               });
+               return selected;
        }
-       // unnecessary when only executing (prefilters)
-       // but it'll be ignored by the caller in that case
-       return selection;
+
+       return inspect( options.dataTypes[ 0 ] ) || !inspected[ "*" ] && inspect( "*" );
 }
 
 // A special extend for ajax options