Add various improvements for resource providers.

PiperOrigin-RevId: 529706437
Change-Id: I20385e031446674584349c301982dbe13b812477

src/xml/xml.cc

@@ -129,7 +129,7 @@ bool mjWriteXML(mjCModel* model, string filename, char* error, int error_sz) {
 
 // find include elements recursively, replace them with subtree from xml file
 static XMLElement* mjIncludeXML(XMLElement* elem, string dir,
-                                int default_provider, vector<string>& included) {
+                                int vfs_provider, vector<string>& included) {
   // include element: process
   if (!strcasecmp(elem->Value(), "include")) {
     // make sure include has no children
@@ -152,9 +152,9 @@ static XMLElement* mjIncludeXML(XMLElement* elem, string dir,
     // get data source
     mjResource *resource = nullptr;
     const char* xmlstring = nullptr;
-    if ((resource = mju_openResource(filename.c_str(), default_provider)) == nullptr) {
+    if ((resource = mju_openResource(filename.c_str(), vfs_provider)) == nullptr) {
       // load from OS filesystem
-      if (!default_provider || (resource = mju_openResource(filename.c_str(), 0)) == nullptr) {
+      if (!vfs_provider || (resource = mju_openResource(filename.c_str(), 0)) == nullptr) {
         throw mjXError(elem, "Could not open file '%s'", filename.c_str());
       }
     }
@@ -215,14 +215,14 @@ static XMLElement* mjIncludeXML(XMLElement* elem, string dir,
     }
 
     // run XMLInclude on first new child
-    return mjIncludeXML(first->ToElement(), dir, default_provider, included);
+    return mjIncludeXML(first->ToElement(), dir, vfs_provider, included);
   }
 
   // otherwise check all child elements, return self
   else {
     XMLElement* child = elem->FirstChildElement();
     while (child) {
-      child = mjIncludeXML(child, dir, default_provider, included);
+      child = mjIncludeXML(child, dir, vfs_provider, included);
       if (child) {
         child = child->NextSiblingElement();
       }
@@ -234,7 +234,7 @@ static XMLElement* mjIncludeXML(XMLElement* elem, string dir,
 
 
 // Main parser function
-mjCModel* mjParseXML(const char* filename, int default_provider, char* error, int error_sz) {
+mjCModel* mjParseXML(const char* filename, int vfs_provider, char* error, int error_sz) {
   LocaleOverride locale_override;
 
   // check arguments
@@ -254,9 +254,9 @@ mjCModel* mjParseXML(const char* filename, int default_provider, char* error, in
   // get data source
   mjResource* resource = nullptr;
   const char* xmlstring = nullptr;
-  if ((resource = mju_openResource(filename, default_provider)) == nullptr) {
+  if ((resource = mju_openResource(filename, vfs_provider)) == nullptr) {
     // load from OS filesystem
-    if (!default_provider || (resource = mju_openResource(filename, 0)) == nullptr) {
+    if (!vfs_provider || (resource = mju_openResource(filename, 0)) == nullptr) {
       if (error) {
         snprintf(error, error_sz, "mjParseXML: could not open file '%s'", filename);
       }
@@ -284,29 +284,37 @@ mjCModel* mjParseXML(const char* filename, int default_provider, char* error, in
   XMLDocument doc;
   doc.Parse(xmlstring, buffer_size);
 
-  // close resource
-  mju_closeResource(resource);
-
-
   // error checking
   if (doc.Error()) {
     if (error) {
       snprintf(error, error_sz, "XML parse error %d:\n%s\n",
                doc.ErrorID(), doc.ErrorStr());
     }
+    mju_closeResource(resource);
     return nullptr;
   }
 
   // get top-level element
   XMLElement* root = doc.RootElement();
   if (!root) {
+    mju_closeResource(resource);
     mjCopyError(error, "XML root element not found", error_sz);
     return nullptr;
   }
 
   // create model, set filedir
   model = new mjCModel;
-  model->modelfiledir = mjuu_getfiledir(filename);
+  const char* dir;
+  int ndir = 0;
+  mju_getResourceDir(resource, &dir, &ndir);
+  if (dir != nullptr) {
+    model->modelfiledir = std::string(dir, ndir);
+  } else {
+    model->modelfiledir = "";
+  }
+
+  // close resource
+  mju_closeResource(resource);
 
   // parse with exceptions
   try {
@@ -314,7 +322,7 @@ mjCModel* mjParseXML(const char* filename, int default_provider, char* error, in
       // find include elements, replace them with subtree from xml file
       vector<string> included;
       included.push_back(filename);
-      mjIncludeXML(root, model->modelfiledir, default_provider, included);
+      mjIncludeXML(root, model->modelfiledir, vfs_provider, included);
 
       // parse MuJoCo model
       mjXReader parser;

src/xml/xml.h

@@ -26,7 +26,7 @@
 bool mjWriteXML(mjCModel* model, std::string filename, char* error, int error_sz);
 
 // Main parser function
-mjCModel* mjParseXML(const char* filename, int default_provider, char* error, int error_sz);
+mjCModel* mjParseXML(const char* filename, int vfs_provider, char* error, int error_sz);
 
 
 #endif  // MUJOCO_SRC_XML_XML_H_

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;