Do not expose plugin_slot.

PiperOrigin-RevId: 683215401
Change-Id: Ic64f7221ed83ca3b0c8cca16eb680ea67c67b564

doc/APIreference/functions.rst

@@ -1516,7 +1516,7 @@ mjs_activatePlugin
 
 .. mujoco-include:: mjs_activatePlugin
 
-Activate plugin, return slot number.
+Activate plugin.
 
 .. _Errorandmemory:
 

doc/includes/references.h

@@ -1739,9 +1739,8 @@ typedef struct mjsOrientation_ {   // alternative orientation specifiers
 } mjsOrientation;
 typedef struct mjsPlugin_ {        // plugin specification
   mjsElement* element;             // element type
-  mjString* name;                  // name
+  mjString* name;                  // instance name
   mjString* plugin_name;           // plugin name
-  int plugin_slot;                 // global registered slot number of the plugin
   mjtByte active;                  // is the plugin active
   mjString* info;                  // message appended to compiler errors
 } mjsPlugin;
@@ -3171,7 +3170,7 @@ int mj_setLengthRange(mjModel* m, mjData* d, int index,
 mjSpec* mj_makeSpec(void);
 mjSpec* mj_copySpec(const mjSpec* s);
 void mj_deleteSpec(mjSpec* s);
-int mjs_activatePlugin(mjSpec* s, const char* name);
+void mjs_activatePlugin(mjSpec* s, const char* name);
 void mj_printFormattedModel(const mjModel* m, const char* filename, const char* float_format);
 void mj_printModel(const mjModel* m, const char* filename);
 void mj_printFormattedData(const mjModel* m, mjData* d, const char* filename,

include/mujoco/mjspec.h

@@ -182,9 +182,8 @@ typedef struct mjsOrientation_ {   // alternative orientation specifiers
 
 typedef struct mjsPlugin_ {        // plugin specification
   mjsElement* element;             // element type
-  mjString* name;                  // name
+  mjString* name;                  // instance name
   mjString* plugin_name;           // plugin name
-  int plugin_slot;                 // global registered slot number of the plugin
   mjtByte active;                  // is the plugin active
   mjString* info;                  // message appended to compiler errors
 } mjsPlugin;

include/mujoco/mujoco.h

@@ -241,8 +241,8 @@ MJAPI mjSpec* mj_copySpec(const mjSpec* s);
 // Free memory allocation in mjSpec.
 MJAPI void mj_deleteSpec(mjSpec* s);
 
-// Activate plugin, return slot number.
+// Activate plugin.
-MJAPI int mjs_activatePlugin(mjSpec* s, const char* name);
+MJAPI void mjs_activatePlugin(mjSpec* s, const char* name);
 
 
 //---------------------------------- Printing ------------------------------------------------------

introspect/functions.py

@@ -1048,7 +1048,7 @@ FUNCTIONS: Mapping[str, FunctionDecl] = dict([
     ('mjs_activatePlugin',
      FunctionDecl(
          name='mjs_activatePlugin',
-         return_type=ValueType(name='int'),
+         return_type=ValueType(name='void'),
          parameters=(
              FunctionParameterDecl(
                  name='s',
@@ -1063,7 +1063,7 @@ FUNCTIONS: Mapping[str, FunctionDecl] = dict([
                  ),
              ),
          ),
-         doc='Activate plugin, return slot number.',
+         doc='Activate plugin.',
      )),
     ('mj_printFormattedModel',
      FunctionDecl(

introspect/structs.py

@@ -8576,7 +8576,7 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                  type=PointerType(
                      inner_type=ValueType(name='mjString'),
                  ),
-                 doc='name',
+                 doc='instance name',
              ),
              StructFieldDecl(
                  name='plugin_name',
@@ -8585,11 +8585,6 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                  ),
                  doc='plugin name',
              ),
-             StructFieldDecl(
-                 name='plugin_slot',
-                 type=ValueType(name='int'),
-                 doc='global registered slot number of the plugin',
-             ),
              StructFieldDecl(
                  name='active',
                  type=ValueType(name='mjtByte'),

python/mujoco/codegen/generate_spec_bindings.py

@@ -461,11 +461,6 @@ def generate_add() -> None:
                 } catch (const py::cast_error &e) {
                   throw pybind11::value_error("plugin.instance_name should be a string.");
                 }
-                try {
-                  plugin.plugin_slot = input->plugin_slot;
-                } catch (const py::cast_error &e) {
-                  throw pybind11::value_error("plugin.plugin_slot should be an int.");
-                }
                 try {
                   plugin.active = input->active;
                 } catch (const py::cast_error &e) {

python/mujoco/specs_test.py

@@ -207,13 +207,11 @@ class SpecsTest(absltest.TestCase):
     plugin = spec.add_plugin(
         name='instance_name',
         plugin_name='mujoco.plugin',
-        plugin_slot=7,
         active=True,
         info='info',
     )
     self.assertEqual(plugin.name, 'instance_name')
     self.assertEqual(plugin.plugin_name, 'mujoco.plugin')
-    self.assertEqual(plugin.plugin_slot, 7)
     self.assertEqual(plugin.active, True)
     self.assertEqual(plugin.info, 'info')
 
@@ -229,7 +227,6 @@ class SpecsTest(absltest.TestCase):
     body_with_plugin = spec.worldbody.add_body(plugin=plugin)
     self.assertEqual(body_with_plugin.plugin.name, 'instance_name')
     self.assertEqual(body_with_plugin.plugin.plugin_name, 'mujoco.plugin')
-    self.assertEqual(body_with_plugin.plugin.plugin_slot, 7)
     self.assertEqual(body_with_plugin.plugin.active, True)
     self.assertEqual(body_with_plugin.plugin.info, 'info')
 

src/user/user_api.cc

@@ -206,16 +206,14 @@ void mjs_addSpec(mjSpec* s, mjSpec* child) {
 
 
 // activate plugin
-int mjs_activatePlugin(mjSpec* s, const char* name) {
+void mjs_activatePlugin(mjSpec* s, const char* name) {
   int plugin_slot = -1;
   const mjpPlugin* plugin = mjp_getPlugin(name, &plugin_slot);
   if (!plugin) {
     mju_error("unknown plugin '%s'", name);
-    return -1;
   }
   mjCModel* model = static_cast<mjCModel*>(s->element);
   model->ActivatePlugin(plugin, plugin_slot);
-  return plugin_slot;
 }
 
 

src/user/user_api.h

@@ -63,8 +63,8 @@ MJAPI void mj_deleteSpec(mjSpec* s);
 // Add spec (model asset) to spec.
 MJAPI void mjs_addSpec(mjSpec* s, mjSpec* child);
 
-// Activate plugin, return slot number.
+// Activate plugin.
-MJAPI int mjs_activatePlugin(mjSpec* s, const char* name);
+MJAPI void mjs_activatePlugin(mjSpec* s, const char* name);
 
 
 //---------------------------------- Attachment ----------------------------------------------------

src/user/user_init.c

@@ -402,6 +402,5 @@ void mjs_defaultKey(mjsKey* key) {
 // default plugin attributes
 void mjs_defaultPlugin(mjsPlugin* plugin) {
   memset(plugin, 0, sizeof(mjsPlugin));
-  plugin->plugin_slot = -1;
 }
 

src/user/user_mesh.cc

@@ -294,7 +294,7 @@ void mjCMesh::LoadSDF() {
   mjCPlugin* plugin_instance = static_cast<mjCPlugin*>(plugin.element);
   model->ResolvePlugin(this, plugin_name, plugin_instance_name, &plugin_instance);
   plugin.element = plugin_instance;
-  const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->spec.plugin_slot);
+  const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->plugin_slot);
   if (!(pplugin->capabilityflags & mjPLUGIN_SDF)) {
     throw mjCError(this, "plugin '%s' does not support signed distance fields", pplugin->name);
   }

src/user/user_model.cc

@@ -315,6 +315,7 @@ void mjCModel::CopyPlugin(std::vector<mjCPlugin*>& dest,
       continue;
     }
     mjCPlugin* candidate = new mjCPlugin(*plugin);
+    candidate->model = this;
     candidate->NameSpace(plugin->model);
     bool referenced = instances.find(candidate->name) != instances.end();
     auto same_name = [candidate](const mjCPlugin* dest) { return dest->name == candidate->name; };
@@ -3973,7 +3974,7 @@ void mjCModel::TryCompile(mjModel*& m, mjData*& d, const mjVFS* vfs) {
   {
     int adr = 0;
     for (int i = 0; i < nplugin; ++i) {
-      m->plugin[i] = plugins_[i]->spec.plugin_slot;
+      m->plugin[i] = plugins_[i]->plugin_slot;
       const int size = plugins_[i]->flattened_attributes.size();
       std::memcpy(m->plugin_attr + adr,
                   plugins_[i]->flattened_attributes.data(), size);
@@ -4499,24 +4500,37 @@ void mjCModel::ActivatePlugin(const mjpPlugin* plugin, int slot) {
 
 void mjCModel::ResolvePlugin(mjCBase* obj, const std::string& plugin_name,
                              const std::string& plugin_instance_name, mjCPlugin** plugin_instance) {
+  std::string pname = plugin_name;
+
+  // if the plugin name is not specified by the user, infer it from the plugin instance
+  if (plugin_name.empty() && !plugin_instance_name.empty()) {
+    mjCBase* plugin_obj = FindObject(mjOBJ_PLUGIN, plugin_instance_name);
+    if (plugin_obj) {
+      pname = static_cast<mjCPlugin*>(plugin_obj)->plugin_name;
+    } else {
+      throw mjCError(obj, "unrecognized name '%s' for plugin instance",
+                     plugin_instance_name.c_str());
+    }
+  }
+
   // if plugin_name is specified, check if it is in the list of active plugins
   // (in XML, active plugins are those declared as <required>)
   int plugin_slot = -1;
-  if (!plugin_name.empty()) {
+  if (!pname.empty()) {
     for (int i = 0; i < active_plugins_.size(); ++i) {
-      if (active_plugins_[i].first->name == plugin_name) {
+      if (active_plugins_[i].first->name == pname) {
         plugin_slot = active_plugins_[i].second;
         break;
       }
     }
     if (plugin_slot == -1) {
-      throw mjCError(obj, "unrecognized plugin '%s'", plugin_name.c_str());
+      throw mjCError(obj, "unrecognized plugin '%s'", pname.c_str());
     }
   }
 
   // implicit plugin instance
-  if (*plugin_instance && (*plugin_instance)->spec.plugin_slot == -1) {
+  if (*plugin_instance && (*plugin_instance)->plugin_slot == -1) {
-      (*plugin_instance)->spec.plugin_slot = plugin_slot;
+      (*plugin_instance)->plugin_slot = plugin_slot;
       (*plugin_instance)->parent = obj;
   }
 
@@ -4524,14 +4538,15 @@ void mjCModel::ResolvePlugin(mjCBase* obj, const std::string& plugin_name,
   else if (!*plugin_instance) {
     *plugin_instance =
         static_cast<mjCPlugin*>(FindObject(mjOBJ_PLUGIN, plugin_instance_name));
+    (*plugin_instance)->plugin_slot = plugin_slot;
     if (!*plugin_instance) {
       throw mjCError(
           obj, "unrecognized name '%s' for plugin instance", plugin_instance_name.c_str());
     }
-    if (plugin_slot != -1 && plugin_slot != (*plugin_instance)->spec.plugin_slot) {
+    if (plugin_slot != -1 && plugin_slot != (*plugin_instance)->plugin_slot) {
       throw mjCError(
           obj, "'plugin' attribute does not match that of the instance");
     }
-    plugin_slot = (*plugin_instance)->spec.plugin_slot;
+    plugin_slot = (*plugin_instance)->plugin_slot;
   }
 }

src/user/user_objects.cc

@@ -1695,7 +1695,7 @@ void mjCBody::Compile(void) {
     mjCPlugin* plugin_instance = static_cast<mjCPlugin*>(plugin.element);
     model->ResolvePlugin(this, plugin_name, plugin_instance_name, &plugin_instance);
     plugin.element = plugin_instance;
-    const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->spec.plugin_slot);
+    const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->plugin_slot);
     if (!(pplugin->capabilityflags & mjPLUGIN_PASSIVE)) {
       throw mjCError(this, "plugin '%s' does not support passive forces", pplugin->name);
     }
@@ -2949,7 +2949,7 @@ void mjCGeom::Compile(void) {
     mjCPlugin* plugin_instance = static_cast<mjCPlugin*>(plugin.element);
     model->ResolvePlugin(this, plugin_name, plugin_instance_name, &plugin_instance);
     plugin.element = plugin_instance;
-    const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->spec.plugin_slot);
+    const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->plugin_slot);
     if (!(pplugin->capabilityflags & mjPLUGIN_SDF)) {
       throw mjCError(this, "plugin '%s' does not support sign distance fields", pplugin->name);
     }
@@ -5908,7 +5908,7 @@ void mjCActuator::Compile(void) {
     mjCPlugin* plugin_instance = static_cast<mjCPlugin*>(plugin.element);
     model->ResolvePlugin(this, plugin_name, plugin_instance_name, &plugin_instance);
     plugin.element = plugin_instance;
-    const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->spec.plugin_slot);
+    const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->plugin_slot);
     if (!(pplugin->capabilityflags & mjPLUGIN_ACTUATOR)) {
       throw mjCError(this, "plugin '%s' does not support actuators", pplugin->name);
     }
@@ -6415,7 +6415,7 @@ void mjCSensor::Compile(void) {
       mjCPlugin* plugin_instance = static_cast<mjCPlugin*>(plugin.element);
       model->ResolvePlugin(this, plugin_name, plugin_instance_name, &plugin_instance);
       plugin.element = plugin_instance;
-      const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->spec.plugin_slot);
+      const mjpPlugin* pplugin = mjp_getPluginAtSlot(plugin_instance->plugin_slot);
       if (!(pplugin->capabilityflags & mjPLUGIN_SENSOR)) {
         throw mjCError(this, "plugin '%s' does not support sensors", pplugin->name);
       }
@@ -6918,6 +6918,7 @@ void mjCKey::Compile(const mjModel* m) {
 mjCPlugin::mjCPlugin(mjCModel* _model) {
   name = "";
   nstate = -1;
+  plugin_slot = -1;
   parent = this;
   model = _model;
   name.clear();
@@ -6945,6 +6946,7 @@ mjCPlugin& mjCPlugin::operator=(const mjCPlugin& other) {
     this->spec = other.spec;
     *static_cast<mjCPlugin_*>(this) = static_cast<const mjCPlugin_&>(other);
     parent = this;
+    plugin_slot = other.plugin_slot;
   }
   return *this;
 }
@@ -6953,7 +6955,9 @@ mjCPlugin& mjCPlugin::operator=(const mjCPlugin& other) {
 
 // compiler
 void mjCPlugin::Compile(void) {
-  const mjpPlugin* plugin = mjp_getPluginAtSlot(spec.plugin_slot);
+  mjCPlugin* plugin_instance = this;
+  model->ResolvePlugin(this, plugin_name, name, &plugin_instance);
+  const mjpPlugin* plugin = mjp_getPluginAtSlot(plugin_slot);
 
   // clear precompiled
   flattened_attributes.clear();

src/user/user_objects.h

@@ -1424,7 +1424,8 @@ class mjCPlugin : public mjCPlugin_ {
   mjCPlugin(const mjCPlugin& other);
   mjCPlugin& operator=(const mjCPlugin& other);
   mjsPlugin spec;
-  mjCBase* parent;   // parent object (only used when generating error message)
+  mjCBase* parent;  // parent object (only used when generating error message)
+  int plugin_slot;  // global registered slot number of the plugin
 
  private:
   void Compile(void);              // compiler

src/xml/xml_native_reader.cc

@@ -2890,7 +2890,7 @@ void mjXReader::Extension(XMLElement* section) {
     if (name == "plugin") {
       string plugin_name;
       ReadAttrTxt(elem, "plugin", plugin_name, /* required = */ true);
-      int plugin_slot = mjs_activatePlugin(spec, plugin_name.c_str());
+      mjs_activatePlugin(spec, plugin_name.c_str());
 
       XMLElement* child = FirstChildElement(elem);
       while (child) {
@@ -2909,7 +2909,6 @@ void mjXReader::Extension(XMLElement* section) {
             throw mjXError(child, "plugin instance must have a name");
           }
           ReadPluginConfigs(child, p);
-          p->plugin_slot = plugin_slot;
         }
         child = NextSiblingElement(child);
       }

src/xml/xml_native_writer.cc

@@ -827,7 +827,7 @@ void mjXWriter::OnePlugin(XMLElement* elem, const mjsPlugin* plugin) {
   } else {
     WriteAttrTxt(elem, "plugin", plugin_name);
     const mjpPlugin* pplugin = mjp_getPluginAtSlot(
-        static_cast<mjCPlugin*>(plugin->element)->spec.plugin_slot);
+        static_cast<mjCPlugin*>(plugin->element)->plugin_slot);
     const char* c = &(static_cast<mjCPlugin*>(plugin->element)->flattened_attributes[0]);
     for (int i = 0; i < pplugin->nattribute; ++i) {
       string value(c);
@@ -1338,7 +1338,7 @@ void mjXWriter::Extension(XMLElement* root) {
     }
 
     // check if we need to open a new <plugin> section
-    const mjpPlugin* plugin = mjp_getPluginAtSlot(pp->spec.plugin_slot);
+    const mjpPlugin* plugin = mjp_getPluginAtSlot(pp->plugin_slot);
     if (plugin != last_plugin) {
       plugin_elem = InsertEnd(section, "plugin");
       WriteAttrTxt(plugin_elem, "plugin", plugin->name);