static UA_StatusCode
readValueAttributeFromNode(UA_Server *server, UA_Session *session,
                           const UA_VariableNode *vn, UA_DataValue *v,
                           UA_NumericRange *rangeptr) {
    if(vn->value.data.callback.onRead) {
        vn->value.data.callback.onRead(server, &session->sessionId,
                                       session->sessionHandle, &vn->nodeId,
                                       vn->context, rangeptr, &vn->value.data.value);
        const UA_Node *old = (const UA_Node *)vn;
        /* Reopen the node to see the changes from onRead */
        vn = (const UA_VariableNode*)UA_Nodestore_get(server, &vn->nodeId);
        UA_Nodestore_release(server, old);
    }
    if(rangeptr)
        return UA_Variant_copyRange(&vn->value.data.value.value, &v->value, *rangeptr);
    *v = vn->value.data.value;
    v->value.storageType = UA_VARIANT_DATA_NODELETE;
    return UA_STATUSCODE_GOOD;
}
static UA_StatusCode
setMonitoredItemSettings(UA_Server *server, UA_MonitoredItem *mon,
                         UA_MonitoringMode monitoringMode,
                         const UA_MonitoringParameters *params,
                         const UA_DataType* dataType) {
    /* Filter */
    if(params->filter.encoding != UA_EXTENSIONOBJECT_DECODED) {
        UA_DataChangeFilter_init(&(mon->filter.dataChangeFilter));
        mon->filter.dataChangeFilter.trigger = UA_DATACHANGETRIGGER_STATUSVALUE;
    } else if(params->filter.content.decoded.type == &UA_TYPES[UA_TYPES_DATACHANGEFILTER]) {
        UA_DataChangeFilter *filter = (UA_DataChangeFilter *)params->filter.content.decoded.data;
        // TODO implement EURange to support UA_DEADBANDTYPE_PERCENT
        switch(filter->deadbandType) {
        case UA_DEADBANDTYPE_NONE:
            break;
        case UA_DEADBANDTYPE_ABSOLUTE:
            if(!dataType || !UA_DataType_isNumeric(dataType))
                return UA_STATUSCODE_BADFILTERNOTALLOWED;
            break;
        case UA_DEADBANDTYPE_PERCENT:
            return UA_STATUSCODE_BADMONITOREDITEMFILTERUNSUPPORTED;
        default:
            return UA_STATUSCODE_BADMONITOREDITEMFILTERUNSUPPORTED;
        }
        UA_DataChangeFilter_copy(filter, &mon->filter.dataChangeFilter);
#ifdef UA_ENABLE_SUBSCRIPTIONS_EVENTS
    } else if (params->filter.content.decoded.type == &UA_TYPES[UA_TYPES_EVENTFILTER]) {
        UA_EventFilter_copy((UA_EventFilter *)params->filter.content.decoded.data,
                            &mon->filter.eventFilter);
#endif
    } else {
        return UA_STATUSCODE_BADMONITOREDITEMFILTERINVALID;
    }

    /* <-- The point of no return --> */

    /* Unregister the callback */
    UA_MonitoredItem_unregisterSampleCallback(server, mon);

    /* Remove the old samples */
    UA_ByteString_deleteMembers(&mon->lastSampledValue);
    UA_Variant_deleteMembers(&mon->lastValue);

    /* ClientHandle */
    mon->clientHandle = params->clientHandle;

    /* SamplingInterval */
    UA_Double samplingInterval = params->samplingInterval;
    if(mon->attributeId == UA_ATTRIBUTEID_VALUE) {
        mon->monitoredItemType = UA_MONITOREDITEMTYPE_CHANGENOTIFY;
        const UA_VariableNode *vn = (const UA_VariableNode *)
            UA_Nodestore_get(server, &mon->monitoredNodeId);
        if(vn) {
            if(vn->nodeClass == UA_NODECLASS_VARIABLE &&
               samplingInterval < vn->minimumSamplingInterval)
                samplingInterval = vn->minimumSamplingInterval;
            UA_Nodestore_release(server, (const UA_Node *)vn);
        }
    } else if(mon->attributeId == UA_ATTRIBUTEID_EVENTNOTIFIER) {
        /* TODO: events should not need a samplinginterval */
        samplingInterval = 10000.0f; // 10 seconds to reduce the load
        mon->monitoredItemType = UA_MONITOREDITEMTYPE_EVENTNOTIFY;
    } else {
        mon->monitoredItemType = UA_MONITOREDITEMTYPE_CHANGENOTIFY;
    }
    mon->samplingInterval = samplingInterval;
    UA_BOUNDEDVALUE_SETWBOUNDS(server->config.samplingIntervalLimits,
                               samplingInterval, mon->samplingInterval);
    if(samplingInterval != samplingInterval) /* Check for nan */
        mon->samplingInterval = server->config.samplingIntervalLimits.min;

    UA_assert(mon->monitoredItemType != 0);

    /* QueueSize */
    UA_BOUNDEDVALUE_SETWBOUNDS(server->config.queueSizeLimits,
                               params->queueSize, mon->maxQueueSize);

    /* DiscardOldest */
    mon->discardOldest = params->discardOldest;

    /* Register sample callback if reporting is enabled */
    mon->monitoringMode = monitoringMode;
    if(monitoringMode == UA_MONITORINGMODE_REPORTING)
        return UA_MonitoredItem_registerSampleCallback(server, mon);

    return UA_STATUSCODE_GOOD;
}
static void
Operation_Read(UA_Server *server, UA_Session *session,
               const UA_ReadValueId *id, UA_DataValue *v) {
    UA_LOG_DEBUG_SESSION(server->config.logger, session,
                         "Read the attribute %i", id->attributeId);

    /* XML encoding is not supported */
    if(id->dataEncoding.name.length > 0 &&
       !UA_String_equal(&binEncoding, &id->dataEncoding.name)) {
           v->hasStatus = true;
           v->status = UA_STATUSCODE_BADDATAENCODINGUNSUPPORTED;
           return;
    }

    /* Index range for an attribute other than value */
    if(id->indexRange.length > 0 && id->attributeId != UA_ATTRIBUTEID_VALUE) {
        v->hasStatus = true;
        v->status = UA_STATUSCODE_BADINDEXRANGENODATA;
        return;
    }

    /* Get the node */
    const UA_Node *node = UA_Nodestore_get(server, &id->nodeId);
    if(!node) {
        v->hasStatus = true;
        v->status = UA_STATUSCODE_BADNODEIDUNKNOWN;
        return;
    }

    /* Read the attribute */
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    switch(id->attributeId) {
    case UA_ATTRIBUTEID_NODEID:
        retval = UA_Variant_setScalarCopy(&v->value, &node->nodeId, &UA_TYPES[UA_TYPES_NODEID]);
        break;
    case UA_ATTRIBUTEID_NODECLASS:
        retval = UA_Variant_setScalarCopy(&v->value, &node->nodeClass, &UA_TYPES[UA_TYPES_NODECLASS]);
        break;
    case UA_ATTRIBUTEID_BROWSENAME:
        retval = UA_Variant_setScalarCopy(&v->value, &node->browseName, &UA_TYPES[UA_TYPES_QUALIFIEDNAME]);
        break;
    case UA_ATTRIBUTEID_DISPLAYNAME:
        retval = UA_Variant_setScalarCopy(&v->value, &node->displayName, &UA_TYPES[UA_TYPES_LOCALIZEDTEXT]);
        break;
    case UA_ATTRIBUTEID_DESCRIPTION:
        retval = UA_Variant_setScalarCopy(&v->value, &node->description, &UA_TYPES[UA_TYPES_LOCALIZEDTEXT]);
        break;
    case UA_ATTRIBUTEID_WRITEMASK:
        retval = UA_Variant_setScalarCopy(&v->value, &node->writeMask, &UA_TYPES[UA_TYPES_UINT32]);
        break;
    case UA_ATTRIBUTEID_USERWRITEMASK: {
        UA_UInt32 userWriteMask = getUserWriteMask(server, session, node);
        retval = UA_Variant_setScalarCopy(&v->value, &userWriteMask, &UA_TYPES[UA_TYPES_UINT32]);
        break; }
    case UA_ATTRIBUTEID_ISABSTRACT:
        retval = readIsAbstractAttribute(node, &v->value);
        break;
    case UA_ATTRIBUTEID_SYMMETRIC:
        CHECK_NODECLASS(UA_NODECLASS_REFERENCETYPE);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_ReferenceTypeNode*)node)->symmetric,
                                          &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    case UA_ATTRIBUTEID_INVERSENAME:
        CHECK_NODECLASS(UA_NODECLASS_REFERENCETYPE);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_ReferenceTypeNode*)node)->inverseName,
                                          &UA_TYPES[UA_TYPES_LOCALIZEDTEXT]);
        break;
    case UA_ATTRIBUTEID_CONTAINSNOLOOPS:
        CHECK_NODECLASS(UA_NODECLASS_VIEW);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_ViewNode*)node)->containsNoLoops,
                                          &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    case UA_ATTRIBUTEID_EVENTNOTIFIER:
        CHECK_NODECLASS(UA_NODECLASS_VIEW | UA_NODECLASS_OBJECT);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_ViewNode*)node)->eventNotifier,
                                          &UA_TYPES[UA_TYPES_BYTE]);
        break;
    case UA_ATTRIBUTEID_VALUE: {
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        /* VariableTypes don't have the AccessLevel concept. Always allow reading the value. */
        if(node->nodeClass == UA_NODECLASS_VARIABLE) {
            /* The access to a value variable is granted via the AccessLevel
             * and UserAccessLevel attributes */
            UA_Byte accessLevel = getAccessLevel(server, session, (const UA_VariableNode*)node);
            if(!(accessLevel & (UA_ACCESSLEVELMASK_READ))) {
                retval = UA_STATUSCODE_BADNOTREADABLE;
                break;
            }
            accessLevel = getUserAccessLevel(server, session,
                                             (const UA_VariableNode*)node);
            if(!(accessLevel & (UA_ACCESSLEVELMASK_READ))) {
                retval = UA_STATUSCODE_BADUSERACCESSDENIED;
                break;
            }
        }
        retval = readValueAttributeComplete(server, session, (const UA_VariableNode*)node,
                                            op_timestampsToReturn, &id->indexRange, v);
        break;
    }
    case UA_ATTRIBUTEID_DATATYPE:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_VariableTypeNode*)node)->dataType,
                                          &UA_TYPES[UA_TYPES_NODEID]);
        break;
    case UA_ATTRIBUTEID_VALUERANK:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_VariableTypeNode*)node)->valueRank,
                                          &UA_TYPES[UA_TYPES_INT32]);
        break;
    case UA_ATTRIBUTEID_ARRAYDIMENSIONS:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        retval = readArrayDimensionsAttribute((const UA_VariableNode*)node, v);
        break;
    case UA_ATTRIBUTEID_ACCESSLEVEL:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_VariableNode*)node)->accessLevel,
                                          &UA_TYPES[UA_TYPES_BYTE]);
        break;
    case UA_ATTRIBUTEID_USERACCESSLEVEL: {
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE);
        UA_Byte userAccessLevel = getUserAccessLevel(server, session,
                                                     (const UA_VariableNode*)node);
        retval = UA_Variant_setScalarCopy(&v->value, &userAccessLevel, &UA_TYPES[UA_TYPES_BYTE]);
        break; }
    case UA_ATTRIBUTEID_MINIMUMSAMPLINGINTERVAL:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_VariableNode*)node)->minimumSamplingInterval,
                                          &UA_TYPES[UA_TYPES_DOUBLE]);
        break;
    case UA_ATTRIBUTEID_HISTORIZING:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_VariableNode*)node)->historizing,
                                          &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    case UA_ATTRIBUTEID_EXECUTABLE:
        CHECK_NODECLASS(UA_NODECLASS_METHOD);
        retval = UA_Variant_setScalarCopy(&v->value, &((const UA_MethodNode*)node)->executable,
                                          &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    case UA_ATTRIBUTEID_USEREXECUTABLE: {
        CHECK_NODECLASS(UA_NODECLASS_METHOD);
        UA_Boolean userExecutable = getUserExecutable(server, session,
                                                      (const UA_MethodNode*)node);
        retval = UA_Variant_setScalarCopy(&v->value, &userExecutable, &UA_TYPES[UA_TYPES_BOOLEAN]);
        break; }
    default:
        retval = UA_STATUSCODE_BADATTRIBUTEIDINVALID;
    }

    /* Release nodes */
    UA_Nodestore_release(server, node);

    /* Return error code when reading has failed */
    if(retval != UA_STATUSCODE_GOOD) {
        v->hasStatus = true;
        v->status = retval;
        return;
    }

    v->hasValue = true;

    /* Create server timestamp */
    if(op_timestampsToReturn == UA_TIMESTAMPSTORETURN_SERVER ||
       op_timestampsToReturn == UA_TIMESTAMPSTORETURN_BOTH) {
        v->serverTimestamp = UA_DateTime_now();
        v->hasServerTimestamp = true;
    }

    /* Handle source time stamp */
    if(id->attributeId == UA_ATTRIBUTEID_VALUE) {
        if(op_timestampsToReturn == UA_TIMESTAMPSTORETURN_SERVER ||
           op_timestampsToReturn == UA_TIMESTAMPSTORETURN_NEITHER) {
            v->hasSourceTimestamp = false;
            v->hasSourcePicoseconds = false;
        } else if(!v->hasSourceTimestamp) {
            v->sourceTimestamp = UA_DateTime_now();
            v->hasSourceTimestamp = true;
        }
    }
}
/* This function implements the main part of the write service and operates on a
   copy of the node (not in single-threaded mode). */
static UA_StatusCode
copyAttributeIntoNode(UA_Server *server, UA_Session *session,
                      UA_Node *node, const UA_WriteValue *wvalue) {
    const void *value = wvalue->value.value.data;
    UA_UInt32 userWriteMask = getUserWriteMask(server, session, node);
    UA_StatusCode retval = UA_STATUSCODE_GOOD;

    const UA_VariableTypeNode *type;

    switch(wvalue->attributeId) {
    case UA_ATTRIBUTEID_NODEID:
    case UA_ATTRIBUTEID_NODECLASS:
    case UA_ATTRIBUTEID_USERWRITEMASK:
    case UA_ATTRIBUTEID_USERACCESSLEVEL:
    case UA_ATTRIBUTEID_USEREXECUTABLE:
        retval = UA_STATUSCODE_BADWRITENOTSUPPORTED;
        break;
    case UA_ATTRIBUTEID_BROWSENAME:
        CHECK_USERWRITEMASK(UA_WRITEMASK_BROWSENAME);
        CHECK_DATATYPE_SCALAR(QUALIFIEDNAME);
        UA_QualifiedName_deleteMembers(&node->browseName);
        UA_QualifiedName_copy((const UA_QualifiedName *)value, &node->browseName);
        break;
    case UA_ATTRIBUTEID_DISPLAYNAME:
        CHECK_USERWRITEMASK(UA_WRITEMASK_DISPLAYNAME);
        CHECK_DATATYPE_SCALAR(LOCALIZEDTEXT);
        UA_LocalizedText_deleteMembers(&node->displayName);
        UA_LocalizedText_copy((const UA_LocalizedText *)value, &node->displayName);
        break;
    case UA_ATTRIBUTEID_DESCRIPTION:
        CHECK_USERWRITEMASK(UA_WRITEMASK_DESCRIPTION);
        CHECK_DATATYPE_SCALAR(LOCALIZEDTEXT);
        UA_LocalizedText_deleteMembers(&node->description);
        UA_LocalizedText_copy((const UA_LocalizedText *)value, &node->description);
        break;
    case UA_ATTRIBUTEID_WRITEMASK:
        CHECK_USERWRITEMASK(UA_WRITEMASK_WRITEMASK);
        CHECK_DATATYPE_SCALAR(UINT32);
        node->writeMask = *(const UA_UInt32*)value;
        break;
    case UA_ATTRIBUTEID_ISABSTRACT:
        CHECK_USERWRITEMASK(UA_WRITEMASK_ISABSTRACT);
        CHECK_DATATYPE_SCALAR(BOOLEAN);
        retval = writeIsAbstractAttribute(node, *(const UA_Boolean*)value);
        break;
    case UA_ATTRIBUTEID_SYMMETRIC:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_REFERENCETYPE);
        CHECK_USERWRITEMASK(UA_WRITEMASK_SYMMETRIC);
        CHECK_DATATYPE_SCALAR(BOOLEAN);
        ((UA_ReferenceTypeNode*)node)->symmetric = *(const UA_Boolean*)value;
        break;
    case UA_ATTRIBUTEID_INVERSENAME:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_REFERENCETYPE);
        CHECK_USERWRITEMASK(UA_WRITEMASK_INVERSENAME);
        CHECK_DATATYPE_SCALAR(LOCALIZEDTEXT);
        UA_LocalizedText_deleteMembers(&((UA_ReferenceTypeNode*)node)->inverseName);
        UA_LocalizedText_copy((const UA_LocalizedText *)value,
                              &((UA_ReferenceTypeNode*)node)->inverseName);
        break;
    case UA_ATTRIBUTEID_CONTAINSNOLOOPS:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_VIEW);
        CHECK_USERWRITEMASK(UA_WRITEMASK_CONTAINSNOLOOPS);
        CHECK_DATATYPE_SCALAR(BOOLEAN);
        ((UA_ViewNode*)node)->containsNoLoops = *(const UA_Boolean*)value;
        break;
    case UA_ATTRIBUTEID_EVENTNOTIFIER:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_VIEW | UA_NODECLASS_OBJECT);
        CHECK_USERWRITEMASK(UA_WRITEMASK_EVENTNOTIFIER);
        CHECK_DATATYPE_SCALAR(BYTE);
        ((UA_ViewNode*)node)->eventNotifier = *(const UA_Byte*)value;
        break;
    case UA_ATTRIBUTEID_VALUE:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        if(node->nodeClass == UA_NODECLASS_VARIABLE) {
            /* The access to a value variable is granted via the AccessLevel
             * and UserAccessLevel attributes */
            UA_Byte accessLevel = getAccessLevel(server, session, (const UA_VariableNode*)node);
            if(!(accessLevel & (UA_ACCESSLEVELMASK_WRITE))) {
                retval = UA_STATUSCODE_BADNOTWRITABLE;
                break;
            }
            accessLevel = getUserAccessLevel(server, session,
                                             (const UA_VariableNode*)node);
            if(!(accessLevel & (UA_ACCESSLEVELMASK_WRITE))) {
                retval = UA_STATUSCODE_BADUSERACCESSDENIED;
                break;
            }
        } else { /* UA_NODECLASS_VARIABLETYPE */
            CHECK_USERWRITEMASK(UA_WRITEMASK_VALUEFORVARIABLETYPE);
        }
        retval = writeValueAttribute(server, session, (UA_VariableNode*)node,
                                     &wvalue->value, &wvalue->indexRange);
        break;
    case UA_ATTRIBUTEID_DATATYPE:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        CHECK_USERWRITEMASK(UA_WRITEMASK_DATATYPE);
        CHECK_DATATYPE_SCALAR(NODEID);
        GET_NODETYPE
        retval = writeDataTypeAttribute(server, session, (UA_VariableNode*)node,
                                        type, (const UA_NodeId*)value);
        UA_Nodestore_release(server, (const UA_Node*)type);
        break;
    case UA_ATTRIBUTEID_VALUERANK:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        CHECK_USERWRITEMASK(UA_WRITEMASK_VALUERANK);
        CHECK_DATATYPE_SCALAR(INT32);
        GET_NODETYPE
        retval = writeValueRankAttribute(server, session, (UA_VariableNode*)node,
                                         type, *(const UA_Int32*)value);
        UA_Nodestore_release(server, (const UA_Node*)type);
        break;
    case UA_ATTRIBUTEID_ARRAYDIMENSIONS:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        CHECK_USERWRITEMASK(UA_WRITEMASK_ARRRAYDIMENSIONS);
        CHECK_DATATYPE_ARRAY(UINT32);
        GET_NODETYPE
        retval = writeArrayDimensionsAttribute(server, session, (UA_VariableNode*)node,
                                               type, wvalue->value.value.arrayLength,
                                               (UA_UInt32 *)wvalue->value.value.data);
        UA_Nodestore_release(server, (const UA_Node*)type);
        break;
    case UA_ATTRIBUTEID_ACCESSLEVEL:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE);
        CHECK_USERWRITEMASK(UA_WRITEMASK_ACCESSLEVEL);
        CHECK_DATATYPE_SCALAR(BYTE);
        ((UA_VariableNode*)node)->accessLevel = *(const UA_Byte*)value;
        break;
    case UA_ATTRIBUTEID_MINIMUMSAMPLINGINTERVAL:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE);
        CHECK_USERWRITEMASK(UA_WRITEMASK_MINIMUMSAMPLINGINTERVAL);
        CHECK_DATATYPE_SCALAR(DOUBLE);
        ((UA_VariableNode*)node)->minimumSamplingInterval = *(const UA_Double*)value;
        break;
    case UA_ATTRIBUTEID_HISTORIZING:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE);
        CHECK_USERWRITEMASK(UA_WRITEMASK_HISTORIZING);
        CHECK_DATATYPE_SCALAR(BOOLEAN);
        ((UA_VariableNode*)node)->historizing = *(const UA_Boolean*)value;
        break;
    case UA_ATTRIBUTEID_EXECUTABLE:
        CHECK_NODECLASS_WRITE(UA_NODECLASS_METHOD);
        CHECK_USERWRITEMASK(UA_WRITEMASK_EXECUTABLE);
        CHECK_DATATYPE_SCALAR(BOOLEAN);
        ((UA_MethodNode*)node)->executable = *(const UA_Boolean*)value;
        break;
    default:
        retval = UA_STATUSCODE_BADATTRIBUTEIDINVALID;
        break;
    }
    if(retval != UA_STATUSCODE_GOOD)
        UA_LOG_INFO_SESSION(server->config.logger, session,
                            "WriteRequest returned status code %s",
                            UA_StatusCode_name(retval));
    return retval;
}