Add various improvements for resource providers.

PiperOrigin-RevId: 529706437
Change-Id: I20385e031446674584349c301982dbe13b812477

src/xml/xml_api.cc

@@ -83,19 +83,19 @@ void mj_deactivate(void) {
 
 
 // mj_loadXML helper function
-mjModel* _loadXML(const char* filename, int default_provider,
+mjModel* _loadXML(const char* filename, int vfs_provider,
                   char* error, int error_sz) {
   // serialize access to themodel
   std::lock_guard<std::mutex> lock(themutex);
 
   // parse new model
-  mjCModel* newmodel = mjParseXML(filename, default_provider, error, error_sz);
+  mjCModel* newmodel = mjParseXML(filename, vfs_provider, error, error_sz);
   if (!newmodel) {
     return nullptr;
   }
 
   // compile new model
-  mjModel* m = newmodel->Compile(default_provider);
+  mjModel* m = newmodel->Compile(vfs_provider);
   if (!m) {
     mjCopyError(error, newmodel->GetError().message, error_sz);
     delete newmodel;