/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 *    Copyright 2019 (c) Fraunhofer IOSB (Author: Klaus Schick)

 *    Copyright 2019, 2025 (c) Fraunhofer IOSB (Author: Julius Pfrommer)

 *    Copyright 2026 (c) o6 Automation GmbH (Author: Julius Pfrommer)

 */

#include "ua_server_internal.h"

/* The layout of the results array is:

 * [results-array] | padding | UA_AsyncResponse | padding | [UA_AsyncOperation]

 *

 * We need to take care about memory alignment (padding). */

static void *

allocateResultsArray(const UA_DataType *resultsType, size_t resultsLen,

                     UA_AsyncResponse **resp, UA_AsyncOperation **ops) {

    const size_t padding = sizeof(size_t) - 1;

    const size_t fixedSize = sizeof(UA_AsyncResponse) + 2 * padding;

    const size_t elementSize =

        resultsType->memSize + sizeof(UA_AsyncOperation);

    /* Reserve the maximum padding at both alignment boundaries. */

    if(resultsLen > (SIZE_MAX - fixedSize) / elementSize)

        return NULL;

    size_t responseBegin =

        (resultsType->memSize * resultsLen + padding) & ~padding;

    size_t opsBegin =

        (responseBegin + sizeof(UA_AsyncResponse) + padding) & ~padding;

    size_t allocationSize =

        opsBegin + sizeof(UA_AsyncOperation) * resultsLen;

    void *arr = UA_calloc(1, allocationSize);

    if(!arr)

        return NULL;

    uintptr_t arrMem = (uintptr_t)arr;

    *resp = (UA_AsyncResponse*)(arrMem + responseBegin);

    *ops = (UA_AsyncOperation*)(arrMem + opsBegin);

    return arr;

}

/* Cancel the operation, but don't _clear it here */

static void

UA_AsyncOperation_cancel(UA_Server *server, UA_AsyncOperation *op,

                         UA_StatusCode opstatus) {

    UA_ServerConfig *sc = &server->config;

    void *cancelPtr = NULL;

    /* Set the status and get the pointer that identifies the operation */

    switch(op->asyncOperationType) {

    case UA_ASYNCOPERATIONTYPE_READ_REQUEST:

        cancelPtr = op->output.read;

        op->output.read->hasStatus = true;

        op->output.read->status = opstatus;

        break;

    case UA_ASYNCOPERATIONTYPE_READ_DIRECT:

        cancelPtr = &op->output.directRead;

        op->output.directRead.hasStatus = true;

        op->output.directRead.status = opstatus;

        break;

    case UA_ASYNCOPERATIONTYPE_WRITE_REQUEST:

        cancelPtr = &op->context.writeValue.value;

        *op->output.write = opstatus;

        break;

    case UA_ASYNCOPERATIONTYPE_WRITE_DIRECT:

        cancelPtr = &op->context.writeValue.value;

        op->output.directWrite = opstatus;

        break;

    case UA_ASYNCOPERATIONTYPE_CALL_REQUEST:

        /* outputArguments is always an allocated pointer, also if the length is zero */

        cancelPtr = op->output.call->outputArguments;

        op->output.call->statusCode = opstatus;

        break;

    case UA_ASYNCOPERATIONTYPE_CALL_DIRECT:

        /* outputArguments is always an allocated pointer, also if the length is zero */

        cancelPtr = op->output.directCall.outputArguments;

        op->output.directCall.statusCode = opstatus;

        break;

    default: UA_assert(false); return;

    }

    /* Notify the application that it must no longer set the async result */

    if(sc->asyncOperationCancelCallback)

        sc->asyncOperationCancelCallback(server, cancelPtr);

}

static void

UA_AsyncOperation_delete(UA_AsyncOperation *op) {

    UA_assert(op->asyncOperationType >= UA_ASYNCOPERATIONTYPE_CALL_DIRECT);

    switch(op->asyncOperationType) {

    case UA_ASYNCOPERATIONTYPE_READ_DIRECT:

        UA_DataValue_clear(&op->output.directRead);

        break;

    case UA_ASYNCOPERATIONTYPE_WRITE_DIRECT:

        break;

    case UA_ASYNCOPERATIONTYPE_CALL_DIRECT:

        UA_CallMethodResult_clear(&op->output.directCall);

        break;

    default: UA_assert(false); break;

    }

    UA_free(op);

}

static void

UA_AsyncResponse_delete(UA_AsyncResponse *ar) {

    UA_NodeId_clear(&ar->sessionId);

    /* Clean up the results array last. Because the results array memory also

     * includes ar. */

    void *arr = NULL;

    size_t arrSize = 0;

    const UA_DataType *arrType;

    if(ar->responseType == &UA_TYPES[UA_TYPES_CALLRESPONSE]) {

        arr = ar->response.callResponse.results;

        arrSize = ar->response.callResponse.resultsSize;

        ar->response.callResponse.results = NULL;

        ar->response.callResponse.resultsSize = 0;

        arrType = &UA_TYPES[UA_TYPES_CALLMETHODRESULT];

    } else if(ar->responseType == &UA_TYPES[UA_TYPES_READRESPONSE]) {

        arr = ar->response.readResponse.results;

        arrSize = ar->response.readResponse.resultsSize;

        ar->response.readResponse.results = NULL;

        ar->response.readResponse.resultsSize = 0;

        arrType = &UA_TYPES[UA_TYPES_DATAVALUE];

    } else /* if(ar->responseType == &UA_TYPES[UA_TYPES_WRITERESPONSE]) */ {

        UA_assert(ar->responseType == &UA_TYPES[UA_TYPES_WRITERESPONSE]);

        arr = ar->response.writeResponse.results;

        arrSize = ar->response.writeResponse.resultsSize;

        ar->response.writeResponse.results = NULL;

        ar->response.writeResponse.resultsSize = 0;

        arrType = &UA_TYPES[UA_TYPES_STATUSCODE];

    }

    UA_clear(&ar->response.callResponse, ar->responseType);

    UA_Array_delete(arr, arrSize, arrType);

}

static void

notifyServiceEnd(UA_Server *server, UA_AsyncResponse *ar,

                 UA_Session *session, UA_SecureChannel *sc) {

    /* Nothing to do? */

    UA_ServerConfig *config = UA_Server_getConfig(server);

    if(!config->globalNotificationCallback && !config->serviceNotificationCallback)

        return;

    /* Collect the payload */

    UA_NodeId sessionId = (session) ? session->sessionId : UA_NODEID_NULL;

    UA_UInt32 secureChannelId = (sc) ? sc->securityToken.channelId : 0;

    UA_NodeId serviceTypeId;

    if(ar->responseType == &UA_TYPES[UA_TYPES_CALLRESPONSE]) {

        serviceTypeId = UA_TYPES[UA_TYPES_CALLREQUEST].typeId;

    } else if(ar->responseType == &UA_TYPES[UA_TYPES_READRESPONSE]) {

        serviceTypeId = UA_TYPES[UA_TYPES_READREQUEST].typeId;

    } else /* if(ar->responseType == &UA_TYPES[UA_TYPES_WRITERESPONSE]) */ {

        serviceTypeId = UA_TYPES[UA_TYPES_WRITEREQUEST].typeId;

    }

    /* Notify the application */

    static UA_THREAD_LOCAL UA_KeyValuePair notifyPayload[4] = {

        {{0, UA_STRING_STATIC("securechannel-id")}, {0}},

        {{0, UA_STRING_STATIC("session-id")}, {0}},

        {{0, UA_STRING_STATIC("request-id")}, {0}},

        {{0, UA_STRING_STATIC("service-type")}, {0}}

    };

    UA_KeyValueMap notifyPayloadMap = {4, notifyPayload};

    if(config->serviceNotificationCallback || config->globalNotificationCallback) {

        UA_Variant_setScalar(&notifyPayload[0].value, &secureChannelId,

                             &UA_TYPES[UA_TYPES_UINT32]);

        UA_Variant_setScalar(&notifyPayload[1].value, &sessionId,

                             &UA_TYPES[UA_TYPES_NODEID]);

        UA_Variant_setScalar(&notifyPayload[2].value, &ar->requestId,

                             &UA_TYPES[UA_TYPES_UINT32]);

        UA_Variant_setScalar(&notifyPayload[3].value, &serviceTypeId,

                             &UA_TYPES[UA_TYPES_NODEID]);

    }

    UA_ApplicationNotificationType nt = UA_APPLICATIONNOTIFICATIONTYPE_SERVICE_END;

    if(config->serviceNotificationCallback)

        config->serviceNotificationCallback(server, nt, notifyPayloadMap);

    if(config->globalNotificationCallback)

        config->globalNotificationCallback(server, nt, notifyPayloadMap);

}

static void

sendAsyncResponse(UA_Server *server, UA_AsyncResponse *ar) {

    UA_assert(ar->opCountdown == 0);

    /* Get the session */

    UA_Session *session = getSessionById(server, &ar->sessionId);

    UA_SecureChannel *channel = (session) ? session->channel : NULL;

    /* Notify that processing the service has ended */

    notifyServiceEnd(server, ar, session, channel);

    /* Check the session */

    if(!session) {

        UA_LOG_WARNING(server->config.logging, UA_LOGCATEGORY_SERVER,

                       "Async Service: Session %N no longer exists", ar->sessionId);

        return;

    }

    /* Check the channel */

    if(!channel) {

        UA_LOG_WARNING_SESSION(server->config.logging, session,

                               "Async Service Response cannot be sent. "

                               "No SecureChannel for the session.");

        return;

    }

    /* Set the request handle */

    UA_ResponseHeader *responseHeader = (UA_ResponseHeader*)

        &ar->response.callResponse.responseHeader;

    responseHeader->requestHandle = ar->requestHandle;

    /* Send the Response */

    UA_StatusCode res = sendResponse(server, channel, ar->requestId,

                                     (UA_Response*)&ar->response, ar->responseType);

    if(res != UA_STATUSCODE_GOOD) {

        UA_LOG_WARNING_SESSION(server->config.logging, session,

                               "Async Response for Req# %" PRIu32 " failed "

                               "with StatusCode %s", ar->requestId,

                               UA_StatusCode_name(res));

    }

}

static void

directOpCallback(UA_Server *server, UA_AsyncOperation *op) {

    switch(op->asyncOperationType) {

    case UA_ASYNCOPERATIONTYPE_READ_DIRECT:

        op->handling.callback.method.read(server,

                                          op->handling.callback.context,

                                          &op->output.directRead);

        break;

    case UA_ASYNCOPERATIONTYPE_WRITE_DIRECT:

        op->handling.callback.method.write(server,

                                           op->handling.callback.context,

                                           op->output.directWrite);

        break;

    case UA_ASYNCOPERATIONTYPE_CALL_DIRECT:

        op->handling.callback.method.call(server,

                                          op->handling.callback.context,

                                          &op->output.directCall);

        break;

    default: UA_assert(false); break;

    }

}

/* Called from the EventLoop via a delayed callback */

static void

UA_AsyncManager_processReady(UA_Server *server, UA_AsyncManager *am) {

    lockServer(server);

    /* Reset the delayed callback */

    UA_atomic_xchg((void**)&am->dc.callback, NULL);

    /* Process ready direct operations and free them */

    UA_AsyncOperation *op = NULL, *op_tmp = NULL;

    TAILQ_FOREACH_SAFE(op, &am->readyOps, pointers, op_tmp) {

        TAILQ_REMOVE(&am->readyOps, op, pointers);

        am->opsCount--;

        directOpCallback(server, op);

        UA_AsyncOperation_delete(op);

    }

    /* Send out ready responses */

    UA_AsyncResponse *ar, *temp;

    TAILQ_FOREACH_SAFE(ar, &am->readyResponses, pointers, temp) {

        TAILQ_REMOVE(&am->readyResponses, ar, pointers);

        sendAsyncResponse(server, ar);

        UA_AsyncResponse_delete(ar);

    }

    unlockServer(server);

}

static void

processOperationResult(UA_Server *server, UA_AsyncOperation *op) {

    UA_AsyncManager *am = &server->asyncManager;

    if(op->asyncOperationType >= UA_ASYNCOPERATIONTYPE_CALL_DIRECT) {

        /* Direct operation */

        TAILQ_REMOVE(&am->waitingOps, op, pointers);

        TAILQ_INSERT_TAIL(&am->readyOps, op, pointers);

    } else {

        /* Part of a service request */

        TAILQ_REMOVE(&am->waitingOps, op, pointers);

        am->opsCount--;

        UA_AsyncResponse *ar = op->handling.response;

        ar->opCountdown -= 1;

        if(ar->opCountdown > 0)

            return;

        /* Enqueue ar in the readyResponses */

        TAILQ_REMOVE(&am->waitingResponses, ar, pointers);

        TAILQ_INSERT_TAIL(&am->readyResponses, ar, pointers);

    }

    /* Trigger the main server thread to handle ready operations and responses */

    if(am->dc.callback == NULL) {

        UA_EventLoop *el = server->config.eventLoop;

        am->dc.callback = (UA_Callback)UA_AsyncManager_processReady;

        am->dc.application = server;

        am->dc.context = am;

        el->addDelayedCallback(el, &am->dc);

        el->cancel(el); /* Wake up the EventLoop if currently waiting in select() */

    }

}

/* Check if any operations have timed out */

static void

checkTimeouts(UA_Server *server, void *_) {

    /* Timeouts are not configured */

    if(server->config.asyncOperationTimeout <= 0.0)

        return;

    lockServer(server);

    UA_EventLoop *el = server->config.eventLoop;

    UA_AsyncManager *am = &server->asyncManager;

    const UA_DateTime tNow = el->dateTime_nowMonotonic(el);

    /* Loop over the waiting ops */

    UA_AsyncOperation *op = NULL, *op_tmp = NULL;

    TAILQ_FOREACH_SAFE(op, &am->waitingOps, pointers, op_tmp) {

        /* Check the timeout */

        if(op->asyncOperationType <= UA_ASYNCOPERATIONTYPE_WRITE_REQUEST) {

            if(tNow <= op->handling.response->timeout)

                continue;

        } else {

            if(tNow <= op->handling.callback.timeout)

                continue;

        }

        UA_LOG_WARNING(server->config.logging, UA_LOGCATEGORY_SERVER,

                       "Operation was removed due to a timeout");

        /* Mark operation as timed out integrate */

        UA_AsyncOperation_cancel(server, op, UA_STATUSCODE_BADTIMEOUT);

        processOperationResult(server, op);

    }

    unlockServer(server);

}

void

UA_AsyncManager_init(UA_AsyncManager *am, UA_Server *server) {

    memset(am, 0, sizeof(UA_AsyncManager));

    TAILQ_INIT(&am->waitingResponses);

    TAILQ_INIT(&am->readyResponses);

    TAILQ_INIT(&am->waitingOps);

    TAILQ_INIT(&am->readyOps);

}

void UA_AsyncManager_start(UA_AsyncManager *am, UA_Server *server) {

    /* Add a regular callback for cleanup and sending finished responses at a

     * 1s interval. */

    UA_StatusCode res = addRepeatedCallback(server, (UA_ServerCallback)checkTimeouts,

                    NULL, 1000.0, &am->checkTimeoutCallbackId);

    if(res != UA_STATUSCODE_GOOD) {

        UA_LOG_WARNING(server->config.logging, UA_LOGCATEGORY_SERVER,

                    "Failed to register async timeout callback. "

                    "Async operations will not be cleaned up on timeout. StatusCode: %s",

                    UA_StatusCode_name(res));

        am->checkTimeoutCallbackId = 0;

    }

}

void UA_AsyncManager_stop(UA_AsyncManager *am, UA_Server *server) {

    removeCallback(server, am->checkTimeoutCallbackId);

    if(am->dc.callback) {

        UA_EventLoop *el = server->config.eventLoop;

        el->removeDelayedCallback(el, &am->dc);

    }

}

void

UA_AsyncManager_clear(UA_AsyncManager *am, UA_Server *server) {

    UA_LOCK_ASSERT(&server->serviceMutex);

    /* Cancel all operations. This moves all operations and responses into the

     * ready state. */

    UA_AsyncOperation *op, *op_tmp;

    TAILQ_FOREACH_SAFE(op, &am->waitingOps, pointers, op_tmp) {

        UA_AsyncOperation_cancel(server, op, UA_STATUSCODE_BADSHUTDOWN);

        processOperationResult(server, op);

    }

    /* This sends out/notifies and removes all direct operations and async requests */

    UA_AsyncManager_processReady(server, am);

    UA_assert(am->opsCount == 0);

}

UA_UInt32

UA_AsyncManager_cancel(UA_Server *server, UA_Session *session, UA_UInt32 requestHandle) {

    UA_LOCK_ASSERT(&server->serviceMutex);

    /* Loop over all waiting operations */

    UA_UInt32 count = 0;

    UA_AsyncOperation *op, *op_tmp;

    UA_AsyncManager *am = &server->asyncManager;

    TAILQ_FOREACH_SAFE(op, &am->waitingOps, pointers, op_tmp) {

        /* Only request operations own a handling.response. */

        if(op->asyncOperationType >= UA_ASYNCOPERATIONTYPE_CALL_DIRECT)

            continue;

        UA_AsyncResponse *ar = op->handling.response;

        if(ar->requestHandle != requestHandle ||

           !UA_NodeId_equal(&session->sessionId, &ar->sessionId))

            continue;

        count++; /* Found a matching request */

        /* Set the status of the overall response */

        ar->response.callResponse.responseHeader.serviceResult =

            UA_STATUSCODE_BADREQUESTCANCELLEDBYCLIENT;

        /* Notify, set operation status and integrate */

        UA_AsyncOperation_cancel(server, op, UA_STATUSCODE_BADOPERATIONABANDONED);

        processOperationResult(server, op);

    }

    return count;

}

static void

persistAsyncResponse(UA_Server *server, UA_Session *session,

                     void *response, UA_AsyncResponse *ar) {

    UA_LOCK_ASSERT(&server->serviceMutex);

    UA_AsyncManager *am = &server->asyncManager;

    /* Pending results, attach the AsyncResponse to the AsyncManager. RequestId

     * and -Handle are set in the AsyncManager before processing the request. */

    ar->requestId = am->currentRequestId;

    ar->requestHandle = am->currentRequestHandle;

    ar->sessionId = session->sessionId;

    ar->timeout = UA_INT64_MAX;

    UA_EventLoop *el = server->config.eventLoop;

    if(server->config.asyncOperationTimeout > 0.0)

        ar->timeout = el->dateTime_nowMonotonic(el) + (UA_DateTime)

            (server->config.asyncOperationTimeout * (UA_DateTime)UA_DATETIME_MSEC);

    /* Move the response content to the AsyncResponse */

    memcpy(&ar->response, response, ar->responseType->memSize);

    UA_init(response, ar->responseType);

    /* Enqueue the ar */

    TAILQ_INSERT_TAIL(&am->waitingResponses, ar, pointers);

}

static void

persistAsyncResponseOperation(UA_Server *server, UA_AsyncOperation *op,

                              UA_AsyncOperationType opType, UA_AsyncResponse *ar,

                              void *outputPtr) {

    /* Set up the async operation */

    op->asyncOperationType = opType;

    op->handling.response = ar;

    op->output.read = (UA_DataValue*)outputPtr;

    /* Not enough resources to store the async operation */

    UA_AsyncManager *am = &server->asyncManager;

    if(server->config.maxAsyncOperationQueueSize != 0 &&

       am->opsCount >= server->config.maxAsyncOperationQueueSize) {

        UA_LOG_WARNING(server->config.logging, UA_LOGCATEGORY_SERVER,

                       "Cannot create async operation: Queue exceeds limit (%d).",

                       (int unsigned)server->config.maxAsyncOperationQueueSize);

        /* No need to call processOperationResult or UA_AsyncOperation_delete

         * here. The response already has the status code integrated. */

        UA_AsyncOperation_cancel(server, op, UA_STATUSCODE_BADTOOMANYOPERATIONS);

        return;

    }

    /* Enqueue the asyncop in the async manager */

    TAILQ_INSERT_TAIL(&am->waitingOps, op, pointers);

    ar->opCountdown++;

    am->opsCount++;

}

static UA_StatusCode

persistAsyncDirectOperation(UA_Server *server, UA_AsyncOperation *op,

                            UA_AsyncOperationType opType, void *context,

                            uintptr_t callback, UA_DateTime timeout) {

    /* Set up the async operation */

    op->asyncOperationType = opType;

    op->handling.callback.timeout = timeout;

    op->handling.callback.context = context;

    op->handling.callback.method.read = (UA_ServerAsyncReadResultCallback)callback;

    /* Not enough resources to store the async operation */

    UA_AsyncManager *am = &server->asyncManager;

    if(server->config.maxAsyncOperationQueueSize != 0 &&

       am->opsCount >= server->config.maxAsyncOperationQueueSize) {

        UA_LOG_WARNING(server->config.logging, UA_LOGCATEGORY_SERVER,

                       "Cannot create async operation: Queue exceeds limit (%d).",

                       (int unsigned)server->config.maxAsyncOperationQueueSize);

        UA_AsyncOperation_cancel(server, op, UA_STATUSCODE_BADTOOMANYOPERATIONS);

        UA_AsyncOperation_delete(op);

        return UA_STATUSCODE_BADTOOMANYOPERATIONS;

    }

    /* Enqueue the asyncop in the async manager */

    TAILQ_INSERT_TAIL(&am->waitingOps, op, pointers);

    am->opsCount++;

    return UA_STATUSCODE_GOOD;

}

void

async_cancel(UA_Server *server, void *context, UA_StatusCode opstatus,

             UA_Boolean cancelSynchronous) {

    UA_AsyncManager *am = &server->asyncManager;

    UA_AsyncOperation *op = NULL, *op_tmp = NULL;

    /* Cancel operations that are still waiting for the result */

    TAILQ_FOREACH_SAFE(op, &am->waitingOps, pointers, op_tmp) {

        /* Only direct operations own a handling.callback. */

        if(op->asyncOperationType < UA_ASYNCOPERATIONTYPE_CALL_DIRECT)

            continue;

        if(op->handling.callback.context != context)

            continue;

        /* Cancel the operation. This sets the StatusCode and calls the

         * asyncOperationCancelCallback. */

        UA_AsyncOperation_cancel(server, op, opstatus);

        /* Call the result-callback of the local async operation.

         * Right away or in the next EventLoop iteration. */

        if(cancelSynchronous) {

            TAILQ_REMOVE(&am->waitingOps, op, pointers);

            am->opsCount--;

            directOpCallback(server, op);

            UA_AsyncOperation_delete(op);

        } else {

            processOperationResult(server, op);

        }

    }

    /* All "ready" operations get processed in the next EventLoop iteration anyway */

    if(!cancelSynchronous)

        return;

    /* Process matching ready operations synchronously and delete them */

    TAILQ_FOREACH_SAFE(op, &am->readyOps, pointers, op_tmp) {

        if(op->handling.callback.context != context)

            continue;

        TAILQ_REMOVE(&am->readyOps, op, pointers);

        am->opsCount--;

        directOpCallback(server, op);

        UA_AsyncOperation_delete(op);

    }

}

void

UA_Server_cancelAsync(UA_Server *server, void *context, UA_StatusCode opstatus,

                      UA_Boolean synchronousResultCallback) {

    lockServer(server);

    async_cancel(server, context, opstatus, synchronousResultCallback);

    unlockServer(server);

}

/********/

/* Read */

/********/

UA_Boolean

Service_Read(UA_Server *server, UA_Session *session, const UA_ReadRequest *request,

             UA_ReadResponse *response) {

    UA_LOG_DEBUG_SESSION(server->config.logging, session, "Processing ReadRequest");

    UA_LOCK_ASSERT(&server->serviceMutex);

    /* Check if the timestampstoreturn is valid */

    if(request->timestampsToReturn > UA_TIMESTAMPSTORETURN_NEITHER) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADTIMESTAMPSTORETURNINVALID;

        return true;

    }

    /* Check if maxAge is valid */

    if(request->maxAge < 0) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADMAXAGEINVALID;

        return true;

    }

    /* Check if there are too many operations */

    if(server->config.maxNodesPerRead != 0 &&

       request->nodesToReadSize > server->config.maxNodesPerRead) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADTOOMANYOPERATIONS;

        return true;

    }

    /* Check if there are no operations */

    if(request->nodesToReadSize == 0) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTHINGTODO;

        return true;

    }

    /* Allocate the results array */

    UA_AsyncResponse *ar = NULL;

    UA_AsyncOperation *aopArray = NULL;

    response->results = (UA_DataValue*)

        allocateResultsArray(&UA_TYPES[UA_TYPES_DATAVALUE],

                             request->nodesToReadSize, &ar, &aopArray);

    if(!response->results) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;

        return true;

    }

    response->resultsSize = request->nodesToReadSize;

    /* Execute the operations */

    for(size_t i = 0; i < request->nodesToReadSize; i++) {

        UA_Boolean done = Operation_Read(server, session, request->timestampsToReturn,

                                         &request->nodesToRead[i], &response->results[i]);

        if(!done)

            persistAsyncResponseOperation(server, &aopArray[i],

                                          UA_ASYNCOPERATIONTYPE_READ_REQUEST,

                                          ar, &response->results[i]);

    }

    /* If async operations are pending, persist them and signal the service is

     * not done */

    if(ar->opCountdown > 0) {

        ar->responseType = &UA_TYPES[UA_TYPES_READRESPONSE];

        persistAsyncResponse(server, session, response, ar);

    }

    return (ar->opCountdown == 0);

}

UA_StatusCode

read_async(UA_Server *server, UA_Session *session, const UA_ReadValueId *operation,

           UA_TimestampsToReturn ttr, UA_ServerAsyncReadResultCallback callback,

           void *context, UA_UInt32 timeout) {

    /* Allocate the async operation. Do this first as we need the pointer to the

     * datavalue to be stable.*/

    UA_AsyncOperation *op = (UA_AsyncOperation*)UA_calloc(1, sizeof(UA_AsyncOperation));

    if(!op)

        return UA_STATUSCODE_BADOUTOFMEMORY;

    UA_AsyncManager *am = &server->asyncManager;

    if(server->config.maxAsyncOperationQueueSize != 0 &&

       am->opsCount >= server->config.maxAsyncOperationQueueSize) {

        UA_free(op);

        return UA_STATUSCODE_BADTOOMANYOPERATIONS;

    }

    UA_DateTime timeoutDate = UA_INT64_MAX;

    if(timeout > 0) {

        UA_EventLoop *el = server->config.eventLoop;

        const UA_DateTime tNow = el->dateTime_nowMonotonic(el);

        timeoutDate = tNow + (timeout * UA_DATETIME_MSEC);

    }

    /* Call the operation */

    UA_Boolean done = Operation_Read(server, session, ttr, operation, &op->output.directRead);

    if(!done)

        return persistAsyncDirectOperation(server, op, UA_ASYNCOPERATIONTYPE_READ_DIRECT,

                                           context, (uintptr_t)callback, timeoutDate);

    callback(server, context, &op->output.directRead);

    UA_DataValue_clear(&op->output.directRead);

    UA_free(op);

    return UA_STATUSCODE_GOOD;

}

UA_StatusCode

UA_Server_read_async(UA_Server *server, const UA_ReadValueId *operation,

                     UA_TimestampsToReturn ttr, UA_ServerAsyncReadResultCallback callback,

                     void *context, UA_UInt32 timeout) {

    lockServer(server);

    UA_StatusCode res = read_async(server, &server->adminSession, operation,

                                   ttr, callback, context, timeout);

    unlockServer(server);

    return res;

}

UA_StatusCode

UA_Server_setAsyncReadResult(UA_Server *server, UA_DataValue *result) {

    lockServer(server);

    UA_AsyncManager *am = &server->asyncManager;

    UA_AsyncOperation *op = NULL;

    TAILQ_FOREACH(op, &am->waitingOps, pointers) {

        if(op->output.read == result || &op->output.directRead == result) {

            processOperationResult(server, op);

            break;

        }

    }

    unlockServer(server);

    return (op) ? UA_STATUSCODE_GOOD : UA_STATUSCODE_BADNOTFOUND;

}

/*********/

/* Write */

/*********/

UA_Boolean

Service_Write(UA_Server *server, UA_Session *session,

              const UA_WriteRequest *request, UA_WriteResponse *response) {

    UA_assert(session != NULL);

    UA_LOG_DEBUG_SESSION(server->config.logging, session,

                         "Processing WriteRequest");

    UA_LOCK_ASSERT(&server->serviceMutex);

    if(server->config.maxNodesPerWrite != 0 &&

       request->nodesToWriteSize > server->config.maxNodesPerWrite) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADTOOMANYOPERATIONS;

        return true;

    }

    if(request->nodesToWriteSize == 0) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTHINGTODO;

        return true;

    }

    /* Allocate the results array */

    UA_AsyncResponse *ar = NULL;

    UA_AsyncOperation *aopArray = NULL;

    response->results = (UA_StatusCode*)

        allocateResultsArray(&UA_TYPES[UA_TYPES_STATUSCODE],

                             request->nodesToWriteSize, &ar, &aopArray);

    if(!response->results) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;

        return true;

    }

    response->resultsSize = request->nodesToWriteSize;

    /* Execute the operations */

    for(size_t i = 0; i < request->nodesToWriteSize; i++) {

        /* Ensure a stable pointer for the writevalue. Doesn't get written to,

         * just used for the lookup of the async operation later on.

         * The original writeValue might be _clear'ed before the lookup. */

        UA_AsyncOperation *aop = &aopArray[i];

        aop->context.writeValue = request->nodesToWrite[i];

        UA_Boolean done = Operation_Write(server, session, &aop->context.writeValue,

                                          &response->results[i]);

        if(!done)

            persistAsyncResponseOperation(server, aop, UA_ASYNCOPERATIONTYPE_WRITE_REQUEST,

                                          ar, &response->results[i]);

    }

    /* If async operations are pending, persist them and signal the service is

     * not done */

    if(ar->opCountdown > 0) {

        ar->responseType = &UA_TYPES[UA_TYPES_WRITERESPONSE];

        persistAsyncResponse(server, session, response, ar);

    }

    return (ar->opCountdown == 0);

}

UA_StatusCode

write_async(UA_Server *server, UA_Session *session, const UA_WriteValue *operation,

            UA_ServerAsyncWriteResultCallback callback, void *context,

            UA_UInt32 timeout) {

    /* Allocate the async operation. Do this first as we need the pointer to the

     * datavalue to be stable.*/

    UA_AsyncOperation *op = (UA_AsyncOperation*)UA_calloc(1, sizeof(UA_AsyncOperation));

    if(!op)

        return UA_STATUSCODE_BADOUTOFMEMORY;

    UA_AsyncManager *am = &server->asyncManager;

    if(server->config.maxAsyncOperationQueueSize != 0 &&

       am->opsCount >= server->config.maxAsyncOperationQueueSize) {

        UA_free(op);

        return UA_STATUSCODE_BADTOOMANYOPERATIONS;

    }

    UA_DateTime timeoutDate = UA_INT64_MAX;

    if(timeout > 0) {

        UA_EventLoop *el = server->config.eventLoop;

        const UA_DateTime tNow = el->dateTime_nowMonotonic(el);

        timeoutDate = tNow + (timeout * UA_DATETIME_MSEC);

    }

    /* Call the operation */

    op->context.writeValue = *operation; /* Stable pointer */

    UA_Boolean done = Operation_Write(server, session, &op->context.writeValue,

                                      &op->output.directWrite);

    if(!done)

        return persistAsyncDirectOperation(server, op, UA_ASYNCOPERATIONTYPE_WRITE_DIRECT,

                                           context, (uintptr_t)callback, timeoutDate);

    /* Done, return right away */

    callback(server, context, op->output.directWrite);

    UA_free(op);

    return UA_STATUSCODE_GOOD;

}

UA_StatusCode

UA_Server_write_async(UA_Server *server, const UA_WriteValue *operation,

                      UA_ServerAsyncWriteResultCallback callback,

                      void *context, UA_UInt32 timeout) {

    lockServer(server);

    UA_StatusCode res = write_async(server, &server->adminSession, operation,

                                    callback, context, timeout);

    unlockServer(server);

    return res;

}

UA_StatusCode

UA_Server_setAsyncWriteResult(UA_Server *server,

                              const UA_DataValue *value,

                              UA_StatusCode result) {

    lockServer(server);

    UA_AsyncManager *am = &server->asyncManager;

    UA_AsyncOperation *op = NULL;

    TAILQ_FOREACH(op, &am->waitingOps, pointers) {

        if(&op->context.writeValue.value == value) {

            if(op->asyncOperationType == UA_ASYNCOPERATIONTYPE_WRITE_REQUEST)

                *op->output.write = result;

            else

                op->output.directWrite = result;

            processOperationResult(server, op);

            break;

        }

    }

    unlockServer(server);

    return (op) ? UA_STATUSCODE_GOOD : UA_STATUSCODE_BADNOTFOUND;

}

/********/

/* Call */

/********/

#ifdef UA_ENABLE_METHODCALLS

UA_Boolean

Service_Call(UA_Server *server, UA_Session *session,

             const UA_CallRequest *request, UA_CallResponse *response) {

    UA_LOG_DEBUG_SESSION(server->config.logging, session, "Processing CallRequest");

    UA_LOCK_ASSERT(&server->serviceMutex);

    if(server->config.maxNodesPerMethodCall != 0 &&

        request->methodsToCallSize > server->config.maxNodesPerMethodCall) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADTOOMANYOPERATIONS;

        return true;

    }

    if(request->methodsToCallSize == 0) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTHINGTODO;

        return true;

    }

    /* Allocate the results array */

    UA_AsyncResponse *ar = NULL;

    UA_AsyncOperation *aopArray = NULL;

    response->results = (UA_CallMethodResult*)

        allocateResultsArray(&UA_TYPES[UA_TYPES_CALLMETHODRESULT],

                             request->methodsToCallSize, &ar, &aopArray);

    if(!response->results) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;

        return true;

    }

    response->resultsSize = request->methodsToCallSize;

    /* Execute the operations */

    for(size_t i = 0; i < request->methodsToCallSize; i++) {

        UA_Boolean done = Operation_CallMethod(server, session, &request->methodsToCall[i],

                                               &response->results[i]);

        if(!done)

            persistAsyncResponseOperation(server, &aopArray[i],

                                          UA_ASYNCOPERATIONTYPE_CALL_REQUEST,

                                          ar, &response->results[i]);

    }

    /* If async operations are pending, persist them and signal the service is

     * not done */

    if(ar->opCountdown > 0) {

        ar->responseType = &UA_TYPES[UA_TYPES_CALLRESPONSE];

        persistAsyncResponse(server, session, response, ar);

    }

    return (ar->opCountdown == 0);

}

UA_StatusCode

call_async(UA_Server *server, UA_Session *session, const UA_CallMethodRequest *operation,

           UA_ServerAsyncMethodResultCallback callback, void *context,

           UA_UInt32 timeout) {

    /* Allocate the async operation. Do this first as we need the pointer to the

     * datavalue to be stable.*/

    UA_AsyncOperation *op = (UA_AsyncOperation*)UA_calloc(1, sizeof(UA_AsyncOperation));

    if(!op)

        return UA_STATUSCODE_BADOUTOFMEMORY;

    UA_AsyncManager *am = &server->asyncManager;

    if(server->config.maxAsyncOperationQueueSize != 0 &&

       am->opsCount >= server->config.maxAsyncOperationQueueSize) {

        UA_free(op);

        return UA_STATUSCODE_BADTOOMANYOPERATIONS;

    }

    UA_DateTime timeoutDate = UA_INT64_MAX;

    if(timeout > 0) {

        UA_EventLoop *el = server->config.eventLoop;

        const UA_DateTime tNow = el->dateTime_nowMonotonic(el);

        timeoutDate = tNow + (timeout * UA_DATETIME_MSEC);

    }

    /* Call the operation */

    UA_Boolean done = Operation_CallMethod(server, session, operation,

                                           &op->output.directCall);

    if(!done)

        return persistAsyncDirectOperation(server, op, UA_ASYNCOPERATIONTYPE_CALL_DIRECT,

                                           context, (uintptr_t)callback, timeoutDate);

    /* Done, return right away */

    callback(server, context, &op->output.directCall);

    UA_CallMethodResult_clear(&op->output.directCall);

    UA_free(op);

    return UA_STATUSCODE_GOOD;

}