open62541/src/server/ua_services_nodemanagement.c

#include "ua_server_internal.h"
#include "ua_services.h"

/************/
/* Add Node */
/************/


static void
Service_AddNodes_single(UA_Server *server, UA_Session *session,
                        const UA_AddNodesItem *item, UA_AddNodesResult *result,
                        UA_InstantiationCallback *instantiationCallback);

static UA_StatusCode
copyChildNodesToNode(UA_Server *server, UA_Session *session, 
                     const UA_NodeId *sourceNodeId, const UA_NodeId *destinationNodeId,
                     UA_InstantiationCallback *instantiationCallback);

static UA_NodeId
instanceFindAggregateByBrowsename(UA_Server *server, UA_Session *session, 
                                  const UA_NodeId *searchInstance, 
                                  const UA_QualifiedName *browseName);

/* copy an existing variable under the given parent. then instantiate the
 * variable for its type */
static UA_StatusCode
copyExistingVariable(UA_Server *server, UA_Session *session, const UA_NodeId *variable,
                     const UA_NodeId *referenceType, const UA_NodeId *parent,
                     UA_InstantiationCallback *instantiationCallback) {
    const UA_VariableNode *node =
        (const UA_VariableNode*)UA_NodeStore_get(server->nodestore, variable);
    if(!node)
        return UA_STATUSCODE_BADNODEIDINVALID;
    if(node->nodeClass != UA_NODECLASS_VARIABLE)
        return UA_STATUSCODE_BADNODECLASSINVALID;

    // copy the variable attributes
    UA_VariableAttributes attr;
    UA_VariableAttributes_init(&attr);
    attr.displayName = node->displayName;
    attr.description = node->description;
    attr.writeMask = node->writeMask;
    attr.userWriteMask = node->userWriteMask;
    if(node->valueSource == UA_VALUESOURCE_DATA)
        attr.value = node->value.data.value.value;
    else {
        // todo: handle data source and make a copy of the current value
    }
    attr.dataType = node->dataType;
    attr.valueRank = node->valueRank;
    attr.arrayDimensionsSize = node->arrayDimensionsSize;
    attr.arrayDimensions = node->arrayDimensions;
    attr.accessLevel = node->accessLevel;
    attr.userAccessLevel = node->userAccessLevel;
    attr.minimumSamplingInterval = node->minimumSamplingInterval;
    attr.historizing = node->historizing;

    UA_AddNodesItem item;
    UA_AddNodesItem_init(&item);
    item.nodeClass = UA_NODECLASS_VARIABLE;
    item.parentNodeId.nodeId = *parent;
    item.referenceTypeId = *referenceType;
    item.browseName = node->browseName;
    item.nodeAttributes.encoding = UA_EXTENSIONOBJECT_DECODED_NODELETE;
    item.nodeAttributes.content.decoded.type = &UA_TYPES[UA_TYPES_VARIABLEATTRIBUTES];
    item.nodeAttributes.content.decoded.data = &attr;
    const UA_Node *vartype = getNodeType(server, (const UA_Node*)node);
    if(vartype)
        item.typeDefinition.nodeId = vartype->nodeId;
    else
        return UA_STATUSCODE_BADTYPEDEFINITIONINVALID;

    /* add the new variable */
    UA_AddNodesResult res;
    UA_AddNodesResult_init(&res);
    Service_AddNodes_single(server, session, &item, &res, instantiationCallback);
    
    /* Copy any aggregated/nested variables/methods/subobjects this object contains 
     * These objects may not be part of the nodes type.
     */
    copyChildNodesToNode(server, session, &node->nodeId, &res.addedNodeId, instantiationCallback);
    
    UA_NodeId_deleteMembers(&res.addedNodeId);
    return res.statusCode;
}

/* Copy an existing object under the given parent. Then instantiate for all
 * hastypedefinitions of the original version. */
static UA_StatusCode
copyExistingObject(UA_Server *server, UA_Session *session, const UA_NodeId *object,
                   const UA_NodeId *referenceType, const UA_NodeId *parent,
                   UA_InstantiationCallback *instantiationCallback) {
    const UA_ObjectNode *node =
        (const UA_ObjectNode*)UA_NodeStore_get(server->nodestore, object);
    if(!node)
        return UA_STATUSCODE_BADNODEIDINVALID;
    if(node->nodeClass != UA_NODECLASS_OBJECT)
        return UA_STATUSCODE_BADNODECLASSINVALID;

    /* Prepare the item */
    UA_ObjectAttributes attr;
    UA_ObjectAttributes_init(&attr);
    attr.displayName = node->displayName;
    attr.description = node->description;
    attr.writeMask = node->writeMask;
    attr.userWriteMask = node->userWriteMask;
    attr.eventNotifier = node->eventNotifier;

    UA_AddNodesItem item;
    UA_AddNodesItem_init(&item);
    item.nodeClass = UA_NODECLASS_OBJECT;
    item.parentNodeId.nodeId = *parent;
    item.referenceTypeId = *referenceType;
    item.browseName = node->browseName;
    item.nodeAttributes.encoding = UA_EXTENSIONOBJECT_DECODED_NODELETE;
    item.nodeAttributes.content.decoded.type = &UA_TYPES[UA_TYPES_OBJECTATTRIBUTES];
    item.nodeAttributes.content.decoded.data = &attr;
    const UA_Node *objtype = getNodeType(server, (const UA_Node*)node);
    if(objtype)
        item.typeDefinition.nodeId = objtype->nodeId;
    else
        return UA_STATUSCODE_BADTYPEDEFINITIONINVALID;

    /* add the new object */
    UA_AddNodesResult res;
    UA_AddNodesResult_init(&res);
    Service_AddNodes_single(server, session, &item, &res, instantiationCallback);
    
    /* Copy any aggregated/nested variables/methods/subobjects this object contains 
     * These objects may not be part of the nodes type.
     */
    copyChildNodesToNode(server, session, &node->nodeId, &res.addedNodeId, instantiationCallback);
    
    UA_NodeId_deleteMembers(&res.addedNodeId);
    
    return res.statusCode;
}

static UA_StatusCode
setObjectInstanceHandle(UA_Server *server, UA_Session *session,
                        UA_ObjectNode* node, void * (*constructor)(const UA_NodeId instance)) {
    if(node->nodeClass != UA_NODECLASS_OBJECT)
        return UA_STATUSCODE_BADNODECLASSINVALID;
    if(!node->instanceHandle)
        node->instanceHandle = constructor(node->nodeId);
    return UA_STATUSCODE_GOOD;
}

static UA_StatusCode
instantiateObjectNode(UA_Server *server, UA_Session *session,
                      const UA_NodeId *nodeId, const UA_NodeId *typeId, size_t depth,
                      UA_InstantiationCallback *instantiationCallback) {
    /* see if the type is derived from baseobjecttype */
    UA_Boolean found = false;
    const UA_NodeId hassubtype = UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE);
    const UA_NodeId baseobjtype = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEOBJECTTYPE);
    UA_StatusCode retval = isNodeInTree(server->nodestore, typeId,
                                        &baseobjtype, &hassubtype, 1, &found);
    if(!found || retval != UA_STATUSCODE_GOOD) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: The object if not derived from BaseObjectType");
        return UA_STATUSCODE_BADTYPEDEFINITIONINVALID;
    }

    /* see if the type node is correct */
    const UA_ObjectTypeNode *typenode =
        (const UA_ObjectTypeNode*)UA_NodeStore_get(server->nodestore, typeId);
    if(!typenode || typenode->nodeClass != UA_NODECLASS_OBJECTTYPE || typenode->isAbstract)
        return UA_STATUSCODE_BADTYPEDEFINITIONINVALID;

    /* Add all the child nodes */
    copyChildNodesToNode(server, session, typeId, nodeId, instantiationCallback);
    
    /* Instantiate supertype attributes if a supertype is available */
    UA_BrowseDescription browseChildren;
    UA_BrowseDescription_init(&browseChildren);
    UA_BrowseResult browseResult;
    UA_BrowseResult_init(&browseResult);
    browseChildren.nodeId = *typeId;
    browseChildren.referenceTypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE);
    browseChildren.includeSubtypes = false;
    browseChildren.browseDirection = UA_BROWSEDIRECTION_INVERSE; // isSubtypeOf
    browseChildren.nodeClassMask = UA_NODECLASS_OBJECTTYPE;
    browseChildren.resultMask = UA_BROWSERESULTMASK_REFERENCETYPEID | UA_BROWSERESULTMASK_NODECLASS;
    // todo: continuation points if there are too many results
    Service_Browse_single(server, session, NULL, &browseChildren, 100, &browseResult);
    for(size_t i = 0; i < browseResult.referencesSize; i++) {
        UA_ReferenceDescription *rd = &browseResult.references[i];
        instantiateObjectNode(server, session, nodeId, &rd->nodeId.nodeId,
                              depth+1, instantiationCallback);
    }
    UA_BrowseResult_deleteMembers(&browseResult);
    
    /* add a hastypedefinition reference */
    if(depth == 0) {
        UA_AddReferencesItem addref;
        UA_AddReferencesItem_init(&addref);
        addref.sourceNodeId = *nodeId;
        addref.referenceTypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_HASTYPEDEFINITION);
        addref.isForward = true;
        addref.targetNodeId.nodeId = *typeId;
        addref.targetNodeClass = UA_NODECLASS_OBJECTTYPE;
        Service_AddReferences_single(server, session, &addref);
    }

    /* call the constructor */
    const UA_ObjectLifecycleManagement *olm = &typenode->lifecycleManagement;
    if(olm->constructor)
        UA_Server_editNode(server, session, nodeId,
                           (UA_EditNodeCallback)setObjectInstanceHandle,
                           olm->constructor);
    return UA_STATUSCODE_GOOD;
}

static UA_StatusCode
instantiateVariableNode(UA_Server *server, UA_Session *session, const UA_NodeId *nodeId,
                        const UA_NodeId *typeId, size_t depth,
                        UA_InstantiationCallback *instantiationCallback) {
    /* see if the type is derived from basevariabletype */
    UA_Boolean found = false;
    const UA_NodeId hassubtype = UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE);
    const UA_NodeId basevartype = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEVARIABLETYPE);
    UA_StatusCode retval = isNodeInTree(server->nodestore, typeId,
                                        &basevartype, &hassubtype, 1, &found);
    if(!found || retval != UA_STATUSCODE_GOOD) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: The variable is not derived from BaseVariableType");
        return UA_STATUSCODE_BADTYPEDEFINITIONINVALID;
    }

    /* see if the type is correct */
    const UA_VariableTypeNode *typenode =
        (const UA_VariableTypeNode*)UA_NodeStore_get(server->nodestore, typeId);
    if(!typenode || typenode->nodeClass != UA_NODECLASS_VARIABLETYPE || typenode->isAbstract)
        return UA_STATUSCODE_BADNODEIDINVALID;

    /* get the references to child properties */
    /* Add all the child nodes */
    copyChildNodesToNode(server, session, typeId, nodeId, instantiationCallback);
    
    /* Instantiate supertypes */
    UA_BrowseDescription browseChildren;
    UA_BrowseDescription_init(&browseChildren);
    UA_BrowseResult browseResult;
    UA_BrowseResult_init(&browseResult);
    browseChildren.nodeId = *typeId;
    browseChildren.referenceTypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE);
    browseChildren.includeSubtypes = false;
    browseChildren.browseDirection = UA_BROWSEDIRECTION_INVERSE; // isSubtypeOf
    browseChildren.nodeClassMask = UA_NODECLASS_VARIABLETYPE;
    browseChildren.resultMask = UA_BROWSERESULTMASK_REFERENCETYPEID | UA_BROWSERESULTMASK_NODECLASS;
    // todo: continuation points if there are too many results
    Service_Browse_single(server, session, NULL, &browseChildren, 100, &browseResult);
    for(size_t i = 0; i < browseResult.referencesSize; i++) {
        UA_ReferenceDescription *rd = &browseResult.references[i];
        instantiateVariableNode(server, session, nodeId, &rd->nodeId.nodeId,
                                depth+1, instantiationCallback);
    }
    UA_BrowseResult_deleteMembers(&browseResult);

    /* add a hastypedefinition reference */
    if(depth == 0) {
        UA_AddReferencesItem addref;
        UA_AddReferencesItem_init(&addref);
        addref.sourceNodeId = *nodeId;
        addref.referenceTypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_HASTYPEDEFINITION);
        addref.isForward = true;
        addref.targetNodeId.nodeId = *typeId;
        addref.targetNodeClass = UA_NODECLASS_OBJECTTYPE;
        /* TODO: Check result */
        Service_AddReferences_single(server, session, &addref);
    }

    return UA_STATUSCODE_GOOD;
} 

/* Search for an instance of "browseName" in node searchInstance
 * Used during copyChildNodes to find overwritable/mergable nodes
 */
static UA_NodeId
instanceFindAggregateByBrowsename(UA_Server *server, UA_Session *session, 
                                  const UA_NodeId *searchInstance, 
                                  const UA_QualifiedName *browseName) {
    UA_NodeId retval = UA_NODEID_NULL;
    
    UA_BrowseDescription browseChildren;
    UA_BrowseDescription_init(&browseChildren);
    UA_NodeId_copy(searchInstance, &browseChildren.nodeId);
    browseChildren.referenceTypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_AGGREGATES);
    browseChildren.includeSubtypes = true;
    browseChildren.browseDirection = UA_BROWSEDIRECTION_FORWARD;
    browseChildren.nodeClassMask = UA_NODECLASS_OBJECT | UA_NODECLASS_VARIABLE | UA_NODECLASS_METHOD;
    browseChildren.resultMask = UA_BROWSERESULTMASK_NODECLASS | UA_BROWSERESULTMASK_BROWSENAME;
    
    UA_BrowseResult browseResult;
    UA_BrowseResult_init(&browseResult);
    Service_Browse_single(server, session, NULL, &browseChildren, 100, &browseResult);
    
    for(size_t i = 0; i < browseResult.referencesSize; i++) {
      UA_ReferenceDescription *rd = &browseResult.references[i];
      if (strncmp((const char*) rd->browseName.name.data, (const char*) browseName->name.data, 
        (browseName->name.length>rd->browseName.name.length ? browseName->name.length : rd->browseName.name.length) ) == 0) {
        // Found
        retval = rd->nodeId.nodeId;
        break;
      }
    }
    
    UA_BrowseResult_deleteMembers(&browseResult);
    return retval;
}

/* Copy any children of Node sourceNodeId to another node destinationNodeId 
 * Used at 2 places: 
 *  (1) During instantiation, when any children of the Type are copied
 *  (2) During instantiation to copy any *nested* instances to the new node
 */
static UA_StatusCode
copyChildNodesToNode(UA_Server* server, UA_Session* session, 
                     const UA_NodeId* sourceNodeId, const UA_NodeId* destinationNodeId, 
                     UA_InstantiationCallback* instantiationCallback) {
  /* Add all the child nodes */
  UA_BrowseDescription browseChildren;
  UA_BrowseDescription_init(&browseChildren);
  UA_NodeId_copy(sourceNodeId, &browseChildren.nodeId);
  browseChildren.referenceTypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_AGGREGATES);
  browseChildren.includeSubtypes = true;
  browseChildren.browseDirection = UA_BROWSEDIRECTION_FORWARD;
  browseChildren.nodeClassMask = UA_NODECLASS_OBJECT | UA_NODECLASS_VARIABLE | UA_NODECLASS_METHOD;
  browseChildren.resultMask = UA_BROWSERESULTMASK_REFERENCETYPEID | UA_BROWSERESULTMASK_NODECLASS | UA_BROWSERESULTMASK_BROWSENAME;
  
  UA_BrowseResult browseResult;
  UA_BrowseResult_init(&browseResult);
  // todo: continuation points if there are too many results
  Service_Browse_single(server, session, NULL, &browseChildren, 100, &browseResult);
  
  for(size_t i = 0; i < browseResult.referencesSize; i++) {
    UA_ReferenceDescription *rd = &browseResult.references[i];
    // Check for deduplication
    UA_NodeId existing = instanceFindAggregateByBrowsename(server, session, destinationNodeId, &rd->browseName);
    if (UA_NodeId_equal(&UA_NODEID_NULL, &existing) == UA_TRUE) {
      if(rd->nodeClass == UA_NODECLASS_METHOD) {
        /* add a reference to the method in the objecttype */
        UA_AddReferencesItem newItem;
        UA_AddReferencesItem_init(&newItem);
        UA_NodeId_copy(destinationNodeId, &newItem.sourceNodeId);
        newItem.referenceTypeId = rd->referenceTypeId;
        newItem.isForward = true;
        newItem.targetNodeId = rd->nodeId;
        newItem.targetNodeClass = UA_NODECLASS_METHOD;
        Service_AddReferences_single(server, session, &newItem);
      } else if(rd->nodeClass == UA_NODECLASS_VARIABLE)
          copyExistingVariable(server, session, &rd->nodeId.nodeId,
                              &rd->referenceTypeId, destinationNodeId, instantiationCallback);
        else if(rd->nodeClass == UA_NODECLASS_OBJECT)
          copyExistingObject(server, session, &rd->nodeId.nodeId,
                            &rd->referenceTypeId, destinationNodeId, instantiationCallback);
    }
  }
  UA_BrowseResult_deleteMembers(&browseResult);
  
  return UA_STATUSCODE_GOOD;
}

static UA_StatusCode
checkParentReference(UA_Server *server, UA_Session *session, UA_NodeClass nodeClass,
                     const UA_NodeId *parentNodeId, const UA_NodeId *referenceTypeId) {
    /* See if the parent exists */
    const UA_Node *parent = UA_NodeStore_get(server->nodestore, parentNodeId);
    if(!parent) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: Parent node not found");
        return UA_STATUSCODE_BADPARENTNODEIDINVALID;
    }

    /* Check the referencetype exists */
    const UA_ReferenceTypeNode *referenceType =
        (const UA_ReferenceTypeNode*)UA_NodeStore_get(server->nodestore, referenceTypeId);
    if(!referenceType) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: Reference type to the parent not found");
        return UA_STATUSCODE_BADREFERENCETYPEIDINVALID;
    }

    /* Check if the referencetype is a reference type node */
    if(referenceType->nodeClass != UA_NODECLASS_REFERENCETYPE) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: Reference type to the parent invalid");
        return UA_STATUSCODE_BADREFERENCETYPEIDINVALID;
    }

    /* Check that the reference type is not abstract */
    if(referenceType->isAbstract == true) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: Abstract reference type to the parent invalid");
        return UA_STATUSCODE_BADREFERENCENOTALLOWED;
    }

    /* Check hassubtype relation for type nodes */
    const UA_NodeId subtypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE);
    if(nodeClass == UA_NODECLASS_DATATYPE ||
       nodeClass == UA_NODECLASS_VARIABLETYPE ||
       nodeClass == UA_NODECLASS_OBJECTTYPE ||
       nodeClass == UA_NODECLASS_REFERENCETYPE) {
        /* type needs hassubtype reference to the supertype */
        if(!UA_NodeId_equal(referenceTypeId, &subtypeId)) {
            UA_LOG_DEBUG_SESSION(server->config.logger, session,
                                 "AddNodes: New type node need to have a "
                                 "hassubtype reference");
            return UA_STATUSCODE_BADREFERENCENOTALLOWED;
        }
        /* supertype needs to be of the same node type  */
        if(parent->nodeClass != nodeClass) {
            UA_LOG_DEBUG_SESSION(server->config.logger, session,
                                 "AddNodes: New type node needs to be of the same "
                                 "node type as the parent");
            return UA_STATUSCODE_BADPARENTNODEIDINVALID;
        }
        return UA_STATUSCODE_GOOD;
    }

    /* Test if the referencetype is hierarchical */
    const UA_NodeId hierarchicalReference =
        UA_NODEID_NUMERIC(0, UA_NS0ID_HIERARCHICALREFERENCES);
    UA_Boolean found = false;
    UA_StatusCode retval = isNodeInTree(server->nodestore, referenceTypeId,
                                        &hierarchicalReference, &subtypeId, 1, &found);
    if(retval != UA_STATUSCODE_GOOD || !found) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: Reference type is not hierarchical");
        return UA_STATUSCODE_BADREFERENCETYPEIDINVALID;
    }

    return UA_STATUSCODE_GOOD;
}

UA_StatusCode
Service_AddNodes_existing(UA_Server *server, UA_Session *session, UA_Node *node,
                          const UA_NodeId *parentNodeId, const UA_NodeId *referenceTypeId,
                          const UA_NodeId *typeDefinition,
                          UA_InstantiationCallback *instantiationCallback,
                          UA_NodeId *addedNodeId) {
    /* Check the namespaceindex */
    if(node->nodeId.namespaceIndex >= server->namespacesSize) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session, "AddNodes: Namespace invalid");
        UA_NodeStore_deleteNode(node);
        return UA_STATUSCODE_BADNODEIDINVALID;
    }

    /* Fall back to a default typedefinition for variables and objects */
    const UA_NodeId basedatavariabletype = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE);
    const UA_NodeId baseobjecttype = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEOBJECTTYPE);
    if(node->nodeClass == UA_NODECLASS_VARIABLE ||
       node->nodeClass == UA_NODECLASS_OBJECT) {
        if(!typeDefinition || UA_NodeId_isNull(typeDefinition)) {
            if(node->nodeClass == UA_NODECLASS_VARIABLE)
                typeDefinition = &basedatavariabletype;
            else
                typeDefinition = &baseobjecttype;
        }
    }

    /* Check the reference to the parent */
    UA_StatusCode retval = checkParentReference(server, session, node->nodeClass,
                                                parentNodeId, referenceTypeId);
    if(retval != UA_STATUSCODE_GOOD) {
        UA_NodeStore_deleteNode(node);
        return retval;
    }

    /* Add the node to the nodestore */
    retval = UA_NodeStore_insert(server->nodestore, node);
    if(retval != UA_STATUSCODE_GOOD) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: Node could not be added to the nodestore "
                             "with error code 0x%08x", retval);
        return retval;
    }

    /* Copy the nodeid if needed */
    if(addedNodeId) {
        retval = UA_NodeId_copy(&node->nodeId, addedNodeId);
        if(retval != UA_STATUSCODE_GOOD) {
            UA_LOG_DEBUG_SESSION(server->config.logger, session,
                                 "AddNodes: Could not copy the nodeid");
            goto remove_node;
        }
    }

    /* Hierarchical reference back to the parent */
    UA_AddReferencesItem item;
    UA_AddReferencesItem_init(&item);
    item.sourceNodeId = node->nodeId;
    item.referenceTypeId = *referenceTypeId;
    item.isForward = false;
    item.targetNodeId.nodeId = *parentNodeId;
    retval = Service_AddReferences_single(server, session, &item);
    if(retval != UA_STATUSCODE_GOOD) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: Could not add the reference to the parent");
        goto remove_node;
    }

    /* Instantiate variables and objects */
    if(node->nodeClass == UA_NODECLASS_OBJECT)
        retval = instantiateObjectNode(server, session, &node->nodeId,
                                       typeDefinition, 0, instantiationCallback);
    else if(node->nodeClass == UA_NODECLASS_VARIABLE)
        retval = instantiateVariableNode(server, session, &node->nodeId,
                                         typeDefinition, 0, instantiationCallback);
    if(retval != UA_STATUSCODE_GOOD) {
        UA_LOG_DEBUG_SESSION(server->config.logger, session,
                             "AddNodes: Could not instantiate the node");
        goto remove_node;
    }

    /* Custom callback */
    if(instantiationCallback)
        instantiationCallback->method(node->nodeId, *typeDefinition,
                                      instantiationCallback->handle);
    return UA_STATUSCODE_GOOD;

 remove_node:
    Service_DeleteNodes_single(server, &adminSession, &node->nodeId, true);
    return retval;
}

/***********************************************/
/* Create a node from an attribute description */
/***********************************************/

static UA_StatusCode
copyStandardAttributes(UA_Node *node, const UA_AddNodesItem *item,
                       const UA_NodeAttributes *attr) {
    UA_StatusCode retval;
    retval  = UA_NodeId_copy(&item->requestedNewNodeId.nodeId, &node->nodeId);
    retval |= UA_QualifiedName_copy(&item->browseName, &node->browseName);
    retval |= UA_LocalizedText_copy(&attr->displayName, &node->displayName);
    retval |= UA_LocalizedText_copy(&attr->description, &node->description);
    node->writeMask = attr->writeMask;
    node->userWriteMask = attr->userWriteMask;
    return retval;
}

static UA_StatusCode
copyCommonVariableAttributes(UA_Server *server, UA_VariableNode *node,
                             const UA_AddNodesItem *item,
                             const UA_VariableAttributes *attr) {
    const UA_NodeId basevartype = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEVARIABLETYPE);
    const UA_NodeId basedatavartype = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE);
    const UA_NodeId *typeDef = &item->typeDefinition.nodeId;
    if(UA_NodeId_isNull(typeDef))
        typeDef = &basedatavartype;
    
    
    /* Make sure we can instantiate the basetypes themselves */
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    if(UA_NodeId_equal(&node->nodeId, &basevartype) == UA_TRUE || 
       UA_NodeId_equal(&node->nodeId, &basedatavartype) == UA_TRUE
    ) {
      node->dataType = UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATATYPE);
      node->valueRank = -2;
      return retval;
    }
    
    const UA_VariableTypeNode *vt =
        (const UA_VariableTypeNode*)UA_NodeStore_get(server->nodestore, typeDef);
    if(!vt || vt->nodeClass != UA_NODECLASS_VARIABLETYPE)
        return UA_STATUSCODE_BADTYPEDEFINITIONINVALID;
    
    /* Set the constraints */
    if(!UA_NodeId_isNull(&attr->dataType))
        retval  = UA_VariableNode_setDataType(server, node, vt, &attr->dataType);
    else /* workaround common error where the datatype is left as NA_NODEID_NULL */
      /* Note that most NS0 VarTypeNodes are DataTypes, not VariableTypes! */
      if (vt->nodeClass == UA_NODECLASS_DATATYPE) 
        UA_NodeId_copy(&vt->nodeId, &node->dataType);
      else
        retval = UA_VariableNode_setDataType(server, node, vt, &vt->dataType);
        
    node->valueRank = -2; /* allow all dimensions first */
    retval |= UA_VariableNode_setArrayDimensions(server, node, vt,
                                                attr->arrayDimensionsSize,
                                                attr->arrayDimensions);

    if(attr->valueRank != 0 || !UA_Variant_isScalar(&attr->value))
        retval |= UA_VariableNode_setValueRank(server, node, vt, attr->valueRank);
    else /* workaround common error where the valuerank is left as 0 */
        retval |= UA_VariableNode_setValueRank(server, node, vt, vt->valueRank);
    
    /* Set the value */
    UA_DataValue value;
    UA_DataValue_init(&value);
    value.value = attr->value;
    value.hasValue = true;
    retval |= UA_VariableNode_setValue(server, node, &value, NULL);
    return retval;
}

static UA_StatusCode
variableNodeFromAttributes(UA_Server *server, UA_VariableNode *vnode,
                           const UA_AddNodesItem *item,
                           const UA_VariableAttributes *attr) {
    vnode->accessLevel = attr->accessLevel;
    vnode->userAccessLevel = attr->userAccessLevel;
    vnode->historizing = attr->historizing;
    vnode->minimumSamplingInterval = attr->minimumSamplingInterval;
    return copyCommonVariableAttributes(server, vnode, item, attr);
}

static UA_StatusCode
variableTypeNodeFromAttributes(UA_Server *server, UA_VariableTypeNode *vtnode,
                               const UA_AddNodesItem *item,
                               const UA_VariableTypeAttributes *attr) {
    vtnode->isAbstract = attr->isAbstract;
    return copyCommonVariableAttributes(server, (UA_VariableNode*)vtnode, item,
                                        (const UA_VariableAttributes*)attr);
}

static UA_StatusCode
objectNodeFromAttributes(UA_ObjectNode *onode, const UA_ObjectAttributes *attr) {
    onode->eventNotifier = attr->eventNotifier;
    return UA_STATUSCODE_GOOD;
}

static UA_StatusCode
referenceTypeNodeFromAttributes(UA_ReferenceTypeNode *rtnode,
                                const UA_ReferenceTypeAttributes *attr) {
    rtnode->isAbstract = attr->isAbstract;
    rtnode->symmetric = attr->symmetric;
    return UA_LocalizedText_copy(&attr->inverseName, &rtnode->inverseName);
}

static UA_StatusCode
objectTypeNodeFromAttributes(UA_ObjectTypeNode *otnode,
                             const UA_ObjectTypeAttributes *attr) {
    otnode->isAbstract = attr->isAbstract;
    return UA_STATUSCODE_GOOD;
}

static UA_StatusCode
viewNodeFromAttributes(UA_ViewNode *vnode, const UA_ViewAttributes *attr) {
    vnode->containsNoLoops = attr->containsNoLoops;
    vnode->eventNotifier = attr->eventNotifier;
    return UA_STATUSCODE_GOOD;
}

static UA_StatusCode
dataTypeNodeFromAttributes(UA_DataTypeNode *dtnode,
                           const UA_DataTypeAttributes *attr) {
    dtnode->isAbstract = attr->isAbstract;
    return UA_STATUSCODE_GOOD;
}

#define CHECK_ATTRIBUTES(TYPE)                                          \
    if(item->nodeAttributes.content.decoded.type != &UA_TYPES[UA_TYPES_##TYPE]) { \
        result->statusCode = UA_STATUSCODE_BADNODEATTRIBUTESINVALID;    \
        break;                                                          \
    }

static void
Service_AddNodes_single(UA_Server *server, UA_Session *session,
                        const UA_AddNodesItem *item, UA_AddNodesResult *result,
                        UA_InstantiationCallback *instantiationCallback) {
    if(item->nodeAttributes.encoding < UA_EXTENSIONOBJECT_DECODED ||
       !item->nodeAttributes.content.decoded.type) {
        result->statusCode = UA_STATUSCODE_BADNODEATTRIBUTESINVALID;
        return;
    }

    /* Create the node */
    UA_Node *node = UA_NodeStore_newNode(item->nodeClass);
    if(!node) {
        // todo: case where the nodeclass is faulty
        result->statusCode = UA_STATUSCODE_BADOUTOFMEMORY;
        return;
    }

    void *data = item->nodeAttributes.content.decoded.data;
    result->statusCode = copyStandardAttributes(node, item, data);
    switch(item->nodeClass) {
    case UA_NODECLASS_OBJECT:
        CHECK_ATTRIBUTES(OBJECTATTRIBUTES);
        result->statusCode |= objectNodeFromAttributes((UA_ObjectNode*)node, data);
        break;
    case UA_NODECLASS_VARIABLE:
        CHECK_ATTRIBUTES(VARIABLEATTRIBUTES);
        result->statusCode |= variableNodeFromAttributes(server, (UA_VariableNode*)node,
                                                         item, data);
        break;
    case UA_NODECLASS_OBJECTTYPE:
        CHECK_ATTRIBUTES(OBJECTTYPEATTRIBUTES);
        result->statusCode |= objectTypeNodeFromAttributes((UA_ObjectTypeNode*)node, data);
        break;
    case UA_NODECLASS_VARIABLETYPE:
        CHECK_ATTRIBUTES(VARIABLETYPEATTRIBUTES);
        result->statusCode |= variableTypeNodeFromAttributes(server, (UA_VariableTypeNode*)node,
                                                             item, data);
        break;
    case UA_NODECLASS_REFERENCETYPE:
        CHECK_ATTRIBUTES(REFERENCETYPEATTRIBUTES);
        result->statusCode |= referenceTypeNodeFromAttributes((UA_ReferenceTypeNode*)node, data);
        break;
    case UA_NODECLASS_DATATYPE:
        CHECK_ATTRIBUTES(DATATYPEATTRIBUTES);
        result->statusCode |= dataTypeNodeFromAttributes((UA_DataTypeNode*)node, data);
        break;
    case UA_NODECLASS_VIEW:
        CHECK_ATTRIBUTES(VIEWATTRIBUTES);
        result->statusCode |= viewNodeFromAttributes((UA_ViewNode*)node, data);
        break;
    case UA_NODECLASS_METHOD:
    case UA_NODECLASS_UNSPECIFIED:
    default:
        result->statusCode = UA_STATUSCODE_BADNODECLASSINVALID;
    }

    if(result->statusCode == UA_STATUSCODE_GOOD) {
        result->statusCode = Service_AddNodes_existing(server, session, node, &item->parentNodeId.nodeId,
                                                       &item->referenceTypeId, &item->typeDefinition.nodeId,
                                                       instantiationCallback, &result->addedNodeId);
    } else {
        UA_LOG_DEBUG_SESSION(server->config.logger, session, "AddNodes: Could not "
                             "prepare the new node with status code 0x%08x", result->statusCode);
        UA_NodeStore_deleteNode(node);
    }
}

void Service_AddNodes(UA_Server *server, UA_Session *session,
                      const UA_AddNodesRequest *request,
                      UA_AddNodesResponse *response) {
    UA_LOG_DEBUG_SESSION(server->config.logger, session, "Processing AddNodesRequest");
    if(request->nodesToAddSize <= 0) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTHINGTODO;
        return;
    }
    size_t size = request->nodesToAddSize;

    response->results = UA_Array_new(size, &UA_TYPES[UA_TYPES_ADDNODESRESULT]);
    if(!response->results) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;
        return;
    }

#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
#ifdef _MSC_VER
    UA_Boolean *isExternal = UA_alloca(size);
    UA_UInt32 *indices = UA_alloca(sizeof(UA_UInt32)*size);
#else
    UA_Boolean isExternal[size];
    UA_UInt32 indices[size];
#endif
    memset(isExternal, false, sizeof(UA_Boolean) * size);
    for(size_t j = 0; j <server->externalNamespacesSize; j++) {
        size_t indexSize = 0;
        for(size_t i = 0;i < size;i++) {
            if(request->nodesToAdd[i].requestedNewNodeId.nodeId.namespaceIndex !=
               server->externalNamespaces[j].index)
                continue;
            isExternal[i] = true;
            indices[indexSize] = (UA_UInt32)i;
            indexSize++;
        }
        if(indexSize == 0)
            continue;
        UA_ExternalNodeStore *ens = &server->externalNamespaces[j].externalNodeStore;
        ens->addNodes(ens->ensHandle, &request->requestHeader,
                      request->nodesToAdd, indices, (UA_UInt32)indexSize,
                      response->results, response->diagnosticInfos);
    }
#endif

    response->resultsSize = size;
    for(size_t i = 0; i < size; i++) {
#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
        if(!isExternal[i])
#endif
            Service_AddNodes_single(server, session, &request->nodesToAdd[i],
                                    &response->results[i], NULL);
    }
}

UA_StatusCode
__UA_Server_addNode(UA_Server *server, const UA_NodeClass nodeClass,
                    const UA_NodeId requestedNewNodeId, const UA_NodeId parentNodeId,
                    const UA_NodeId referenceTypeId, const UA_QualifiedName browseName,
                    const UA_NodeId typeDefinition, const UA_NodeAttributes *attr,
                    const UA_DataType *attributeType,
                    UA_InstantiationCallback *instantiationCallback, UA_NodeId *outNewNodeId) {
    /* prepare the item */
    UA_AddNodesItem item;
    UA_AddNodesItem_init(&item);
    item.parentNodeId.nodeId = parentNodeId;
    item.referenceTypeId = referenceTypeId;
    item.requestedNewNodeId.nodeId = requestedNewNodeId;
    item.browseName = browseName;
    item.nodeClass = nodeClass;
    item.typeDefinition.nodeId = typeDefinition;
    item.nodeAttributes = (UA_ExtensionObject){
        .encoding = UA_EXTENSIONOBJECT_DECODED_NODELETE,
        .content.decoded = {attributeType, (void*)(uintptr_t)attr}};

    /* run the service */
    UA_AddNodesResult result;
    UA_AddNodesResult_init(&result);
    UA_RCU_LOCK();
    Service_AddNodes_single(server, &adminSession, &item, &result, instantiationCallback);
    UA_RCU_UNLOCK();

    /* prepare the output */
    if(outNewNodeId && result.statusCode == UA_STATUSCODE_GOOD)
        *outNewNodeId = result.addedNodeId;
    else
        UA_NodeId_deleteMembers(&result.addedNodeId);
    return result.statusCode;
}

/**************************************************/
/* Add Special Nodes (not possible over the wire) */
/**************************************************/

UA_StatusCode
UA_Server_addDataSourceVariableNode(UA_Server *server, const UA_NodeId requestedNewNodeId,
                                    const UA_NodeId parentNodeId, const UA_NodeId referenceTypeId,
                                    const UA_QualifiedName browseName, const UA_NodeId typeDefinition,
                                    const UA_VariableAttributes attr, const UA_DataSource dataSource,
                                    UA_NodeId *outNewNodeId) {
    /* Create the new node */
    UA_VariableNode *node = UA_NodeStore_newVariableNode();
    if(!node)
        return UA_STATUSCODE_BADOUTOFMEMORY;

    /* Read the current value (to do typechecking) */
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    UA_VariableAttributes editAttr = attr;
    UA_DataValue value;
    UA_DataValue_init(&value);
    if(dataSource.read)
        retval = dataSource.read(dataSource.handle, requestedNewNodeId,
                                 false, NULL, &value);
    else
        retval = UA_STATUSCODE_BADTYPEMISMATCH;
    editAttr.value = value.value;

    if(retval != UA_STATUSCODE_GOOD) {
        UA_NodeStore_deleteNode((UA_Node*)node);
        return retval;
    }

    /* Copy attributes into node */
    UA_AddNodesItem item;
    UA_AddNodesItem_init(&item);
    item.requestedNewNodeId.nodeId = requestedNewNodeId;
    item.browseName = browseName;
    item.typeDefinition.nodeId = typeDefinition;
    item.parentNodeId.nodeId = parentNodeId;
    retval |= copyStandardAttributes((UA_Node*)node, &item, (const UA_NodeAttributes*)&editAttr);
    retval |= copyCommonVariableAttributes(server, node, &item, &editAttr);
    UA_DataValue_deleteMembers(&node->value.data.value);
    node->valueSource = UA_VALUESOURCE_DATASOURCE;
    node->value.dataSource = dataSource;
    UA_DataValue_deleteMembers(&value);
    if(retval != UA_STATUSCODE_GOOD) {
        UA_NodeStore_deleteNode((UA_Node*)node);
        return retval;
    }

    /* Add the node */
    UA_AddNodesResult result;
    UA_AddNodesResult_init(&result);
    UA_RCU_LOCK();
    retval = Service_AddNodes_existing(server, &adminSession, (UA_Node*)node, &parentNodeId,
                                       &referenceTypeId, &typeDefinition, NULL, outNewNodeId);
    UA_RCU_UNLOCK();
    return retval;
}

#ifdef UA_ENABLE_METHODCALLS

UA_StatusCode
UA_Server_addMethodNode(UA_Server *server, const UA_NodeId requestedNewNodeId,
                        const UA_NodeId parentNodeId, const UA_NodeId referenceTypeId,
                        const UA_QualifiedName browseName, const UA_MethodAttributes attr,
                        UA_MethodCallback method, void *handle,
                        size_t inputArgumentsSize, const UA_Argument* inputArguments,
                        size_t outputArgumentsSize, const UA_Argument* outputArguments,
                        UA_NodeId *outNewNodeId) {
    UA_MethodNode *node = UA_NodeStore_newMethodNode();
    if(!node)
        return UA_STATUSCODE_BADOUTOFMEMORY;

    UA_AddNodesItem item;
    UA_AddNodesItem_init(&item);
    item.requestedNewNodeId.nodeId = requestedNewNodeId;
    item.browseName = browseName;
    copyStandardAttributes((UA_Node*)node, &item, (const UA_NodeAttributes*)&attr);
    node->executable = attr.executable;
    node->userExecutable = attr.userExecutable;
    node->attachedMethod = method;
    node->methodHandle = handle;

    /* Add the node */
    UA_NodeId newMethodId;
    UA_NodeId_init(&newMethodId);
    UA_RCU_LOCK();
    UA_StatusCode retval = Service_AddNodes_existing(server, &adminSession, (UA_Node*)node, &parentNodeId,
                                                     &referenceTypeId, &UA_NODEID_NULL, NULL, &newMethodId);
    UA_RCU_UNLOCK();
    if(retval != UA_STATUSCODE_GOOD)
        return retval;

    const UA_NodeId hasproperty = UA_NODEID_NUMERIC(0, UA_NS0ID_HASPROPERTY);
    const UA_NodeId propertytype = UA_NODEID_NUMERIC(0, UA_NS0ID_PROPERTYTYPE);

    if(inputArgumentsSize > 0) {
        UA_VariableNode *inputArgumentsVariableNode = UA_NodeStore_newVariableNode();
        inputArgumentsVariableNode->nodeId.namespaceIndex = newMethodId.namespaceIndex;
        inputArgumentsVariableNode->browseName = UA_QUALIFIEDNAME_ALLOC(0, "InputArguments");
        inputArgumentsVariableNode->displayName = UA_LOCALIZEDTEXT_ALLOC("en_US", "InputArguments");
        inputArgumentsVariableNode->description = UA_LOCALIZEDTEXT_ALLOC("en_US", "InputArguments");
        inputArgumentsVariableNode->valueRank = 1;

        /* UAExport creates a monitoreditem on inputarguments ... */
        inputArgumentsVariableNode->minimumSamplingInterval = 10000.0f;

        //TODO: 0.3 work item: the addMethodNode API does not have the possibility to set nodeIDs
        //actually we need to change the signature to pass UA_NS0ID_SERVER_GETMONITOREDITEMS_INPUTARGUMENTS
        //and UA_NS0ID_SERVER_GETMONITOREDITEMS_OUTPUTARGUMENTS into the function :/
        if(newMethodId.namespaceIndex == 0 &&
           newMethodId.identifierType == UA_NODEIDTYPE_NUMERIC &&
           newMethodId.identifier.numeric == UA_NS0ID_SERVER_GETMONITOREDITEMS) {
            inputArgumentsVariableNode->nodeId =
                UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER_GETMONITOREDITEMS_INPUTARGUMENTS);
        }
        UA_Variant_setArrayCopy(&inputArgumentsVariableNode->value.data.value.value,
                                inputArguments, inputArgumentsSize,
                                &UA_TYPES[UA_TYPES_ARGUMENT]);
        inputArgumentsVariableNode->value.data.value.hasValue = true;
        UA_RCU_LOCK();
        // todo: check if adding succeeded
        Service_AddNodes_existing(server, &adminSession, (UA_Node*)inputArgumentsVariableNode,
                                  &newMethodId, &hasproperty, &propertytype, NULL, NULL);
        UA_RCU_UNLOCK();
    }

    if(outputArgumentsSize > 0) {
        /* create OutputArguments */
        UA_VariableNode *outputArgumentsVariableNode  = UA_NodeStore_newVariableNode();
        outputArgumentsVariableNode->nodeId.namespaceIndex = newMethodId.namespaceIndex;
        outputArgumentsVariableNode->browseName  = UA_QUALIFIEDNAME_ALLOC(0, "OutputArguments");
        outputArgumentsVariableNode->displayName = UA_LOCALIZEDTEXT_ALLOC("en_US", "OutputArguments");
        outputArgumentsVariableNode->description = UA_LOCALIZEDTEXT_ALLOC("en_US", "OutputArguments");
        outputArgumentsVariableNode->valueRank = 1;
        //FIXME: comment in line 882
        if(newMethodId.namespaceIndex == 0 &&
           newMethodId.identifierType == UA_NODEIDTYPE_NUMERIC &&
           newMethodId.identifier.numeric == UA_NS0ID_SERVER_GETMONITOREDITEMS) {
            outputArgumentsVariableNode->nodeId =
                UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER_GETMONITOREDITEMS_OUTPUTARGUMENTS);
        }
        UA_Variant_setArrayCopy(&outputArgumentsVariableNode->value.data.value.value,
                                outputArguments, outputArgumentsSize,
                                &UA_TYPES[UA_TYPES_ARGUMENT]);
        outputArgumentsVariableNode->value.data.value.hasValue = true;
        UA_RCU_LOCK();
        // todo: check if adding succeeded
        Service_AddNodes_existing(server, &adminSession, (UA_Node*)outputArgumentsVariableNode,
                                  &newMethodId, &hasproperty, &propertytype, NULL, NULL);
        UA_RCU_UNLOCK();
    }

    if(outNewNodeId)
        *outNewNodeId = newMethodId;
    else
        UA_NodeId_deleteMembers(&newMethodId);
    return retval;
}

#endif

/******************/
/* Add References */
/******************/

/* Adds a one-way reference to the local nodestore */
static UA_StatusCode
addOneWayReference(UA_Server *server, UA_Session *session,
                   UA_Node *node, const UA_AddReferencesItem *item) {
    size_t i = node->referencesSize;
    size_t refssize = (i+1) | 3; // so the realloc is not necessary every time
    UA_ReferenceNode *new_refs = UA_realloc(node->references, sizeof(UA_ReferenceNode) * refssize);
    if(!new_refs)
        return UA_STATUSCODE_BADOUTOFMEMORY;
    node->references = new_refs;
    UA_ReferenceNode_init(&new_refs[i]);
    UA_StatusCode retval = UA_NodeId_copy(&item->referenceTypeId, &new_refs[i].referenceTypeId);
    retval |= UA_ExpandedNodeId_copy(&item->targetNodeId, &new_refs[i].targetId);
    new_refs[i].isInverse = !item->isForward;
    if(retval == UA_STATUSCODE_GOOD)
        node->referencesSize = i+1;
    else
        UA_ReferenceNode_deleteMembers(&new_refs[i]);
    return retval;
}

UA_StatusCode
Service_AddReferences_single(UA_Server *server, UA_Session *session,
                             const UA_AddReferencesItem *item) {
UA_StatusCode retval = UA_STATUSCODE_GOOD;
#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
    UA_Boolean handledExternally = UA_FALSE;
#endif
    if(item->targetServerUri.length > 0)
        return UA_STATUSCODE_BADNOTIMPLEMENTED; // currently no expandednodeids are allowed

#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
    for(size_t j = 0; j <server->externalNamespacesSize; j++) {
        if(item->sourceNodeId.namespaceIndex != server->externalNamespaces[j].index) {
                continue;
        } else {
            UA_ExternalNodeStore *ens = &server->externalNamespaces[j].externalNodeStore;
            retval = ens->addOneWayReference(ens->ensHandle, item);
            handledExternally = UA_TRUE;
            break;
        }
    }
    if(handledExternally == UA_FALSE) {
#endif
    /* cast away the const to loop the call through UA_Server_editNode beware
     * the "if" above for external nodestores */
    retval = UA_Server_editNode(server, session, &item->sourceNodeId,
                                (UA_EditNodeCallback)addOneWayReference, item);
#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
    }
#endif

    if(retval != UA_STATUSCODE_GOOD)
        return retval;

    UA_AddReferencesItem secondItem;
    secondItem = *item;
    secondItem.targetNodeId.nodeId = item->sourceNodeId;
    secondItem.sourceNodeId = item->targetNodeId.nodeId;
    secondItem.isForward = !item->isForward;
#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
    handledExternally = UA_FALSE;
    for(size_t j = 0; j <server->externalNamespacesSize; j++) {
        if(secondItem.sourceNodeId.namespaceIndex != server->externalNamespaces[j].index) {
                continue;
        } else {
            UA_ExternalNodeStore *ens = &server->externalNamespaces[j].externalNodeStore;
            retval = ens->addOneWayReference(ens->ensHandle, &secondItem);
            handledExternally = UA_TRUE;
            break;
        }

    }
    if(handledExternally == UA_FALSE) {
#endif
    retval = UA_Server_editNode(server, session, &secondItem.sourceNodeId,
                                (UA_EditNodeCallback)addOneWayReference, &secondItem);
#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
    }
#endif
    // todo: remove reference if the second direction failed
    return retval;
}

void Service_AddReferences(UA_Server *server, UA_Session *session,
                           const UA_AddReferencesRequest *request,
                           UA_AddReferencesResponse *response) {
    UA_LOG_DEBUG_SESSION(server->config.logger, session,
                         "Processing AddReferencesRequest");
    if(request->referencesToAddSize <= 0) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTHINGTODO;
        return;
    }
    size_t size = request->referencesToAddSize;

    if(!(response->results = UA_malloc(sizeof(UA_StatusCode) * size))) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;
        return;
    }
    response->resultsSize = size;

#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
#ifdef NO_ALLOCA
    UA_Boolean isExternal[size];
    UA_UInt32 indices[size];
#else
    UA_Boolean *isExternal = UA_alloca(sizeof(UA_Boolean) * size);
    UA_UInt32 *indices = UA_alloca(sizeof(UA_UInt32) * size);
#endif /*NO_ALLOCA */
    memset(isExternal, false, sizeof(UA_Boolean) * size);
    for(size_t j = 0; j < server->externalNamespacesSize; j++) {
        size_t indicesSize = 0;
        for(size_t i = 0;i < size;i++) {
            if(request->referencesToAdd[i].sourceNodeId.namespaceIndex
               != server->externalNamespaces[j].index)
                continue;
            isExternal[i] = true;
            indices[indicesSize] = (UA_UInt32)i;
            indicesSize++;
        }
        if (indicesSize == 0)
            continue;
        UA_ExternalNodeStore *ens = &server->externalNamespaces[j].externalNodeStore;
        ens->addReferences(ens->ensHandle, &request->requestHeader, request->referencesToAdd,
                           indices, (UA_UInt32)indicesSize, response->results, response->diagnosticInfos);
    }
#endif

    for(size_t i = 0; i < response->resultsSize; i++) {
#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
        if(!isExternal[i])
#endif
            response->results[i] = Service_AddReferences_single(server, session, &request->referencesToAdd[i]);
    }
}

UA_StatusCode
UA_Server_addReference(UA_Server *server, const UA_NodeId sourceId,
                       const UA_NodeId refTypeId, const UA_ExpandedNodeId targetId,
                       UA_Boolean isForward) {
    UA_AddReferencesItem item;
    UA_AddReferencesItem_init(&item);
    item.sourceNodeId = sourceId;
    item.referenceTypeId = refTypeId;
    item.isForward = isForward;
    item.targetNodeId = targetId;
    UA_RCU_LOCK();
    UA_StatusCode retval = Service_AddReferences_single(server, &adminSession, &item);
    UA_RCU_UNLOCK();
    return retval;
}

/****************/
/* Delete Nodes */
/****************/

static UA_StatusCode
deleteOneWayReference(UA_Server *server, UA_Session *session, UA_Node *node,
                      const UA_DeleteReferencesItem *item);

UA_StatusCode
Service_DeleteNodes_single(UA_Server *server, UA_Session *session,
                           const UA_NodeId *nodeId, UA_Boolean deleteReferences) {
    const UA_Node *node = UA_NodeStore_get(server->nodestore, nodeId);
    if(!node)
        return UA_STATUSCODE_BADNODEIDUNKNOWN;

    /* destroy an object before removing it */
    if(node->nodeClass == UA_NODECLASS_OBJECT) {
        /* find the object type(s) */
        UA_BrowseDescription bd;
        UA_BrowseDescription_init(&bd);
        bd.browseDirection = UA_BROWSEDIRECTION_INVERSE;
        bd.nodeId = *nodeId;
        bd.referenceTypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE);
        bd.includeSubtypes = true;
        bd.nodeClassMask = UA_NODECLASS_OBJECTTYPE;

        /* browse type definitions with admin rights */
        UA_BrowseResult result;
        UA_BrowseResult_init(&result);
        Service_Browse_single(server, &adminSession, NULL, &bd, UA_UINT32_MAX, &result);
        for(size_t i = 0; i < result.referencesSize; i++) {
            /* call the destructor */
            UA_ReferenceDescription *rd = &result.references[i];
            const UA_ObjectTypeNode *typenode =
                (const UA_ObjectTypeNode*)UA_NodeStore_get(server->nodestore, &rd->nodeId.nodeId);
            if(!typenode)
                continue;
            if(typenode->nodeClass != UA_NODECLASS_OBJECTTYPE || !typenode->lifecycleManagement.destructor)
                continue;

            /* if there are several types with lifecycle management, call all the destructors */
            typenode->lifecycleManagement.destructor(*nodeId, ((const UA_ObjectNode*)node)->instanceHandle);
        }
        UA_BrowseResult_deleteMembers(&result);
    }

    /* remove references */
    /* TODO: check if consistency is violated */
    if(deleteReferences == true) { 
        for(size_t i = 0; i < node->referencesSize; i++) {
            UA_DeleteReferencesItem item;
            UA_DeleteReferencesItem_init(&item);
            item.isForward = node->references[i].isInverse;
            item.sourceNodeId = node->references[i].targetId.nodeId;
            item.targetNodeId.nodeId = node->nodeId;
            UA_Server_editNode(server, session, &node->references[i].targetId.nodeId,
                               (UA_EditNodeCallback)deleteOneWayReference, &item);
        }
    }

    return UA_NodeStore_remove(server->nodestore, nodeId);
}

void Service_DeleteNodes(UA_Server *server, UA_Session *session,
                         const UA_DeleteNodesRequest *request,
                         UA_DeleteNodesResponse *response) {
    UA_LOG_DEBUG_SESSION(server->config.logger, session,
                         "Processing DeleteNodesRequest");
    if(request->nodesToDeleteSize == 0) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTHINGTODO;
        return;
    }

    response->results = UA_malloc(sizeof(UA_StatusCode) * request->nodesToDeleteSize);
    if(!response->results) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;;
        return;
    }

    response->resultsSize = request->nodesToDeleteSize;
    for(size_t i = 0; i < request->nodesToDeleteSize; i++) {
        UA_DeleteNodesItem *item = &request->nodesToDelete[i];
        response->results[i] = Service_DeleteNodes_single(server, session, &item->nodeId,
                                                          item->deleteTargetReferences);
    }
}

UA_StatusCode
UA_Server_deleteNode(UA_Server *server, const UA_NodeId nodeId,
                     UA_Boolean deleteReferences) {
    UA_RCU_LOCK();
    UA_StatusCode retval = Service_DeleteNodes_single(server, &adminSession,
                                                      &nodeId, deleteReferences);
    UA_RCU_UNLOCK();
    return retval;
}

/*********************/
/* Delete References */
/*********************/

// TODO: Check consistency constraints, remove the references.
static UA_StatusCode
deleteOneWayReference(UA_Server *server, UA_Session *session, UA_Node *node,
                      const UA_DeleteReferencesItem *item) {
    UA_Boolean edited = false;
    for(size_t i = node->referencesSize-1; ; i--) {
        if(i > node->referencesSize)
            break; /* underflow after i == 0 */
        if(!UA_NodeId_equal(&item->targetNodeId.nodeId, &node->references[i].targetId.nodeId))
            continue;
        if(!UA_NodeId_equal(&item->referenceTypeId, &node->references[i].referenceTypeId))
            continue;
        if(item->isForward == node->references[i].isInverse)
            continue;
        /* move the last entry to override the current position */
        UA_ReferenceNode_deleteMembers(&node->references[i]);
        node->references[i] = node->references[node->referencesSize-1];
        node->referencesSize--;
        edited = true;
        break;
    }
    if(!edited)
        return UA_STATUSCODE_UNCERTAINREFERENCENOTDELETED;
    /* we removed the last reference */
    if(node->referencesSize == 0 && node->references)
        UA_free(node->references);
    return UA_STATUSCODE_GOOD;;
}

UA_StatusCode
Service_DeleteReferences_single(UA_Server *server, UA_Session *session,
                                const UA_DeleteReferencesItem *item) {
    UA_StatusCode retval = UA_Server_editNode(server, session, &item->sourceNodeId,
                                              (UA_EditNodeCallback)deleteOneWayReference, item);
    if(retval != UA_STATUSCODE_GOOD)
        return retval;
    if(!item->deleteBidirectional || item->targetNodeId.serverIndex != 0)
        return retval;
    UA_DeleteReferencesItem secondItem;
    UA_DeleteReferencesItem_init(&secondItem);
    secondItem.isForward = !item->isForward;
    secondItem.sourceNodeId = item->targetNodeId.nodeId;
    secondItem.targetNodeId.nodeId = item->sourceNodeId;
    return UA_Server_editNode(server, session, &secondItem.sourceNodeId,
                              (UA_EditNodeCallback)deleteOneWayReference, &secondItem);
}

void
Service_DeleteReferences(UA_Server *server, UA_Session *session,
                         const UA_DeleteReferencesRequest *request,
                         UA_DeleteReferencesResponse *response) {
    UA_LOG_DEBUG_SESSION(server->config.logger, session,
                         "Processing DeleteReferencesRequest");
    if(request->referencesToDeleteSize <= 0) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTHINGTODO;
        return;
    }

    response->results = UA_malloc(sizeof(UA_StatusCode) * request->referencesToDeleteSize);
    if(!response->results) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;;
        return;
    }
    response->resultsSize = request->referencesToDeleteSize;

    for(size_t i = 0; i < request->referencesToDeleteSize; i++)
        response->results[i] =
            Service_DeleteReferences_single(server, session, &request->referencesToDelete[i]);
}

UA_StatusCode
UA_Server_deleteReference(UA_Server *server, const UA_NodeId sourceNodeId,
                          const UA_NodeId referenceTypeId,
                          UA_Boolean isForward, const UA_ExpandedNodeId targetNodeId,
                          UA_Boolean deleteBidirectional) {
    UA_DeleteReferencesItem item;
    item.sourceNodeId = sourceNodeId;
    item.referenceTypeId = referenceTypeId;
    item.isForward = isForward;
    item.targetNodeId = targetNodeId;
    item.deleteBidirectional = deleteBidirectional;
    UA_RCU_LOCK();
    UA_StatusCode retval = Service_DeleteReferences_single(server, &adminSession, &item);
    UA_RCU_UNLOCK();
    return retval;
}

/**********************/
/* Set Value Callback */
/**********************/

static UA_StatusCode
setValueCallback(UA_Server *server, UA_Session *session,
                 UA_VariableNode *node, UA_ValueCallback *callback) {
    if(node->nodeClass != UA_NODECLASS_VARIABLE)
        return UA_STATUSCODE_BADNODECLASSINVALID;
    node->value.data.callback = *callback;
    return UA_STATUSCODE_GOOD;
}

UA_StatusCode UA_EXPORT
UA_Server_setVariableNode_valueCallback(UA_Server *server, const UA_NodeId nodeId,
                                        const UA_ValueCallback callback) {
    UA_RCU_LOCK();
    UA_StatusCode retval = UA_Server_editNode(server, &adminSession, &nodeId,
                                              (UA_EditNodeCallback)setValueCallback, &callback);
    UA_RCU_UNLOCK();
    return retval;
}

/******************/
/* Set DataSource */
/******************/

static UA_StatusCode
setDataSource(UA_Server *server, UA_Session *session,
              UA_VariableNode* node, UA_DataSource *dataSource) {
    if(node->nodeClass != UA_NODECLASS_VARIABLE)
        return UA_STATUSCODE_BADNODECLASSINVALID;
    if(node->valueSource == UA_VALUESOURCE_DATA)
        UA_DataValue_deleteMembers(&node->value.data.value);
    node->value.dataSource = *dataSource;
    node->valueSource = UA_VALUESOURCE_DATASOURCE;
    return UA_STATUSCODE_GOOD;
}

UA_StatusCode
UA_Server_setVariableNode_dataSource(UA_Server *server, const UA_NodeId nodeId,
                                     const UA_DataSource dataSource) {
    UA_RCU_LOCK();
    UA_StatusCode retval = UA_Server_editNode(server, &adminSession, &nodeId,
                                              (UA_EditNodeCallback)setDataSource, &dataSource);
    UA_RCU_UNLOCK();
    return retval;
}

/****************************/
/* Set Lifecycle Management */
/****************************/

static UA_StatusCode
setObjectTypeLifecycleManagement(UA_Server *server, UA_Session *session,
                                 UA_ObjectTypeNode* node,
                                 UA_ObjectLifecycleManagement *olm) {
    if(node->nodeClass != UA_NODECLASS_OBJECTTYPE)
        return UA_STATUSCODE_BADNODECLASSINVALID;
    node->lifecycleManagement = *olm;
    return UA_STATUSCODE_GOOD;
}

UA_StatusCode UA_EXPORT
UA_Server_setObjectTypeNode_lifecycleManagement(UA_Server *server, UA_NodeId nodeId,
                                                UA_ObjectLifecycleManagement olm) {
    UA_RCU_LOCK();
    UA_StatusCode retval = UA_Server_editNode(server, &adminSession, &nodeId,
                                              (UA_EditNodeCallback)setObjectTypeLifecycleManagement, &olm);
    UA_RCU_UNLOCK();
    return retval;
}

/***********************/
/* Set Method Callback */
/***********************/

#ifdef UA_ENABLE_METHODCALLS

struct addMethodCallback {
    UA_MethodCallback callback;
    void *handle;
};

static UA_StatusCode
editMethodCallback(UA_Server *server, UA_Session* session, UA_Node* node, const void* handle) {
    if(node->nodeClass != UA_NODECLASS_METHOD)
        return UA_STATUSCODE_BADNODECLASSINVALID;
    const struct addMethodCallback *newCallback = handle;
    UA_MethodNode *mnode = (UA_MethodNode*) node;
    mnode->attachedMethod = newCallback->callback;
    mnode->methodHandle   = newCallback->handle;
    return UA_STATUSCODE_GOOD;
}

UA_StatusCode UA_EXPORT
UA_Server_setMethodNode_callback(UA_Server *server, const UA_NodeId methodNodeId,
                                 UA_MethodCallback method, void *handle) {
    struct addMethodCallback cb = { method, handle };
    UA_RCU_LOCK();
    UA_StatusCode retval = UA_Server_editNode(server, &adminSession,
                                              &methodNodeId, editMethodCallback, &cb);
    UA_RCU_UNLOCK();
    return retval;
}

#endif