refactor the algorithm for testing the cors

while here:
- send cors headers even if the status is 404
- add: access_control_expose_headers config option - list of additional headers sent in Access-Control-Expose-Headers
- add: access_control_allow_credentials config option - if true return Access-Control-Allow-Credentials header equal "true"

winixd/core/request.cpp

@@ -1531,37 +1531,10 @@ void Request::PrepareSessionCookie()
 }
 
 
-// preflight request are tested in function->MakeOption()
-void Request::CheckCorsHeaders()
-{
-	pt::Space * origin = headers_in.get_space_nc(L"Origin");
-
-	if( origin && origin->is_wstr() && function )
-	{
-		if( !out_headers.has_key(Header::access_control_allow_origin) )
-		{
-			if( function->IsCorsOriginAvailable(*origin->get_wstr()) )
-			{
-				function->AddAccessControlAllowOriginHeader(*origin->get_wstr());
-			}
-		}
-
-		if( !out_headers.has_key(Header::access_control_allow_credentials) )
-		{
-			if( function->AreCorsCredentialsAvailable() )
-			{
-				function->AddAccessControlAllowCredentialsHeader();
-			}
-		}
-	}
-}
-
-
 
 void Request::PrepareHeaders(bool compressing, int compress_encoding, size_t output_size)
 {
 	PrepareSessionCookie();
-	CheckCorsHeaders();
 
 	if( send_as_attachment )
 	{