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Help with timer and JavaScript slot.

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  • kshegunovK kshegunov

    @SPlatten said in Help with timer and JavaScript slot.:

    I cannot call currentThread() from pobjGetScriptEng(), it returns a pointer to QJSEngine.

    Correct. I meant to write:

    Q_ASSERT(clsJSON::pobjGetScriptEng()->thread() == QThread::currentThread());
    
    SPlattenS Offline
    SPlattenS Offline
    SPlatten
    wrote on last edited by
    #28

    @kshegunov , have now changed code to:

    ptmrScript = new QTimer(this);
    ptmrScript->moveToThread(pobjScriptEngThread);
    ptmrScript->setInterval(cuintInterval);
    

    Output is now different:

    setupForm() !!!!
    S000000000028E000000000716T09:06:20.132W:QObject: Cannot create children for a parent that is in a different thread.
    (Parent is clsScriptHelper(0x600000202820), parent's thread is QThread(0x600000004150), current thread is QThread(0x60000025e1c0)
    S000000000029E000000000716T09:06:20.132W:QObject::startTimer: Timers cannot be started from another thread
    S000000000030E000000000716T09:06:20.132DL00000688F../clsScriptHelper.cpp[void clsScriptHelper::createTimer]
    Is timer active: true
    S000000000031E000000000716T09:06:20.132DL00000207Fsimon2.js[void clsScriptHelper::log]
    setupForm() !!!!
    

    I will add another API function to allow the script to start the timer.

    Kind Regards,
    Sy

    JonBJ 1 Reply Last reply
    0
    • SPlattenS SPlatten

      @kshegunov , have now changed code to:

      ptmrScript = new QTimer(this);
      ptmrScript->moveToThread(pobjScriptEngThread);
      ptmrScript->setInterval(cuintInterval);
      

      Output is now different:

      setupForm() !!!!
      S000000000028E000000000716T09:06:20.132W:QObject: Cannot create children for a parent that is in a different thread.
      (Parent is clsScriptHelper(0x600000202820), parent's thread is QThread(0x600000004150), current thread is QThread(0x60000025e1c0)
      S000000000029E000000000716T09:06:20.132W:QObject::startTimer: Timers cannot be started from another thread
      S000000000030E000000000716T09:06:20.132DL00000688F../clsScriptHelper.cpp[void clsScriptHelper::createTimer]
      Is timer active: true
      S000000000031E000000000716T09:06:20.132DL00000207Fsimon2.js[void clsScriptHelper::log]
      setupForm() !!!!
      

      I will add another API function to allow the script to start the timer.

      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by JonB
      #29

      @SPlatten said in Help with timer and JavaScript slot.:

      Cannot create children for a parent that is in a different thread.

      You still have this. Excuse my complete guesswork, but do you need to go new QTimer(); rather than new QTimer(this); to move to another thread? (I have never been sure which statement causes the error message, which you can discover by stepping over or putting in qDebug() markers.)

      But if all this is beyond me and being solved by @kshegunov please ignore me --- I'm just watching the discussion :)

      1 Reply Last reply
      0
      • SPlattenS SPlatten

        @kshegunov , realised that after posting, modified output to:

        qdbg() << "Script Eng Thread: " << pobjScriptEng->thread();
        qdbg() << "Before Timer creation: " << pobjCurrThread;
        

        Result is:

        S000000000028E000000000784T09:03:45.243DL00000642F../clsScriptHelper.cpp[void clsScriptHelper::createTimer]
        Script Eng Thread: QThread(0x60000000c0d0)
        S000000000029E000000000784T09:03:45.243DL00000643F../clsScriptHelper.cpp[void clsScriptHelper::createTimer]
        Before Timer creation: QThread(0x60000026f260)
        S000000000030E000000000784T09:03:45.243W:QObject: Cannot create children for a parent that is in a different thread.
        (Parent is clsScriptHelper(0x600000208d80), parent's thread is QThread(0x60000000c0d0), current thread is QThread(0x60000026f260)
        S000000000031E000000000784T09:03:45.244DL00000664F../clsScriptHelper.cpp[void clsScriptHelper::createTimer]
        Before QObject::connect: QThread(0x60000026f260)
        
        kshegunovK Offline
        kshegunovK Offline
        kshegunov
        Moderators
        wrote on last edited by kshegunov
        #30

        Right, so now comes the million bucks question(s):

        Why is clsScriptHelper::createTimer called from thread different from the one pobjScriptEng has affinity for?
        Why do you need to use threads to begin with?

        As for the "solution":

        QMetaObject::Connection cn = QObject::connect(ptmrScript
                                                                 ,&QTimer::timeout
        

        Shall provide a context object for the execution. Looking at the body, I'd say it should be something like:

        QMetaObject::Connection cn = QObject::connect(ptmrScript , &QTimer::timeout, pobjScriptEng
                                                                 ,[pobjScriptEng
                                                                  ,ptmrScript
                                                                  ,strFile
                                                                  ,strFunc
                                                                  ,strScriptWithCall]() {
        

        Also the timer should be created with the correct affinity, I assume:

        ptmrScript = new QTimer(pobjScriptEng);
        

        The original questions stand notwithstanding

        PS: You have race conditions all over the place ...

        Read and abide by the Qt Code of Conduct

        SPlattenS 2 Replies Last reply
        0
        • kshegunovK kshegunov

          Right, so now comes the million bucks question(s):

          Why is clsScriptHelper::createTimer called from thread different from the one pobjScriptEng has affinity for?
          Why do you need to use threads to begin with?

          As for the "solution":

          QMetaObject::Connection cn = QObject::connect(ptmrScript
                                                                   ,&QTimer::timeout
          

          Shall provide a context object for the execution. Looking at the body, I'd say it should be something like:

          QMetaObject::Connection cn = QObject::connect(ptmrScript , &QTimer::timeout, pobjScriptEng
                                                                   ,[pobjScriptEng
                                                                    ,ptmrScript
                                                                    ,strFile
                                                                    ,strFunc
                                                                    ,strScriptWithCall]() {
          

          Also the timer should be created with the correct affinity, I assume:

          ptmrScript = new QTimer(pobjScriptEng);
          

          The original questions stand notwithstanding

          PS: You have race conditions all over the place ...

          SPlattenS Offline
          SPlattenS Offline
          SPlatten
          wrote on last edited by
          #31

          @kshegunov , createTimer is called by JavaScript:

          function setupForm() {
          	//Query all people	  
          	xmleng.log(0, "setupForm() !!!!", cstrThis, 202);
          	//Create request counter property
          	xmleng.setProperty(cstrFormTest, cstrStageCtr, "0");
          	//Create timer to issue SQL requests
          	xmleng.createTimer("t1", 50, "simon2.js@testTimer");
          	xmleng.log(0, "setupForm() !!!!", cstrThis, 207);
          	xmleng.startTimer("t1");
          };
          
          

          Kind Regards,
          Sy

          1 Reply Last reply
          0
          • kshegunovK kshegunov

            Right, so now comes the million bucks question(s):

            Why is clsScriptHelper::createTimer called from thread different from the one pobjScriptEng has affinity for?
            Why do you need to use threads to begin with?

            As for the "solution":

            QMetaObject::Connection cn = QObject::connect(ptmrScript
                                                                     ,&QTimer::timeout
            

            Shall provide a context object for the execution. Looking at the body, I'd say it should be something like:

            QMetaObject::Connection cn = QObject::connect(ptmrScript , &QTimer::timeout, pobjScriptEng
                                                                     ,[pobjScriptEng
                                                                      ,ptmrScript
                                                                      ,strFile
                                                                      ,strFunc
                                                                      ,strScriptWithCall]() {
            

            Also the timer should be created with the correct affinity, I assume:

            ptmrScript = new QTimer(pobjScriptEng);
            

            The original questions stand notwithstanding

            PS: You have race conditions all over the place ...

            SPlattenS Offline
            SPlattenS Offline
            SPlatten
            wrote on last edited by
            #32

            @kshegunov , I've modified my source to:

             QMetaObject::Connection cn = QObject::connect(ptmrScript
                                                          ,&QTimer::timeout
                                                          ,pobjScriptEng
                                                          ,[pobjScriptEng
                                                           ,ptmrScript
                                                           ,strFile
                                                           ,strFunc
                                                           ,strScriptWithCall]() {
            

            still getting:

            S000000000027E000000000747T09:17:30.915DL00000202Fsimon2.js[void clsScriptHelper::log]
            setupForm() !!!!
            S000000000028E000000000747T09:17:30.915DL00000207Fsimon2.js[void clsScriptHelper::log]
            setupForm() !!!!
            S000000000029E000000000747T09:17:30.915W:QObject::startTimer: Timers cannot be started from another thread
            

            Kind Regards,
            Sy

            kshegunovK 1 Reply Last reply
            0
            • SPlattenS SPlatten

              @kshegunov , I've modified my source to:

               QMetaObject::Connection cn = QObject::connect(ptmrScript
                                                            ,&QTimer::timeout
                                                            ,pobjScriptEng
                                                            ,[pobjScriptEng
                                                             ,ptmrScript
                                                             ,strFile
                                                             ,strFunc
                                                             ,strScriptWithCall]() {
              

              still getting:

              S000000000027E000000000747T09:17:30.915DL00000202Fsimon2.js[void clsScriptHelper::log]
              setupForm() !!!!
              S000000000028E000000000747T09:17:30.915DL00000207Fsimon2.js[void clsScriptHelper::log]
              setupForm() !!!!
              S000000000029E000000000747T09:17:30.915W:QObject::startTimer: Timers cannot be started from another thread
              
              kshegunovK Offline
              kshegunovK Offline
              kshegunov
              Moderators
              wrote on last edited by
              #33

              @SPlatten said in Help with timer and JavaScript slot.:

              still getting

              Did you also parent the timer to the QJSEngine?

              Read and abide by the Qt Code of Conduct

              SPlattenS 1 Reply Last reply
              0
              • kshegunovK kshegunov

                @SPlatten said in Help with timer and JavaScript slot.:

                still getting

                Did you also parent the timer to the QJSEngine?

                SPlattenS Offline
                SPlattenS Offline
                SPlatten
                wrote on last edited by SPlatten
                #34

                @kshegunov, this is how it is now:

                QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                QThread* pobjScriptEngThread(pobjScriptEng->thread());
                //Create new timer
                ptmrScript = new QTimer();
                ptmrScript->moveToThread(pobjScriptEngThread);
                ptmrScript->setInterval(cuintInterval);
                

                Have just modified to:

                QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                QThread* pobjScriptEngThread(pobjScriptEng->thread());
                //Create new timer
                ptmrScript = new QTimer();
                ptmrScript->setParent(pobjScriptEng);
                ptmrScript->moveToThread(pobjScriptEngThread);
                ptmrScript->setInterval(cuintInterval);
                

                Output is still:

                S000000000027E000000000743T09:24:17.520DL00000202Fsimon2.js[void clsScriptHelper::log]
                setupForm() !!!!
                S000000000028E000000000743T09:24:17.520W:QObject::setParent: Cannot set parent, new parent is in a different thread
                S000000000029E000000000743T09:24:17.520DL00000207Fsimon2.js[void clsScriptHelper::log]
                setupForm() !!!!
                

                Kind Regards,
                Sy

                JonBJ kshegunovK KroMignonK 3 Replies Last reply
                0
                • SPlattenS SPlatten

                  @kshegunov, this is how it is now:

                  QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                  QThread* pobjScriptEngThread(pobjScriptEng->thread());
                  //Create new timer
                  ptmrScript = new QTimer();
                  ptmrScript->moveToThread(pobjScriptEngThread);
                  ptmrScript->setInterval(cuintInterval);
                  

                  Have just modified to:

                  QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                  QThread* pobjScriptEngThread(pobjScriptEng->thread());
                  //Create new timer
                  ptmrScript = new QTimer();
                  ptmrScript->setParent(pobjScriptEng);
                  ptmrScript->moveToThread(pobjScriptEngThread);
                  ptmrScript->setInterval(cuintInterval);
                  

                  Output is still:

                  S000000000027E000000000743T09:24:17.520DL00000202Fsimon2.js[void clsScriptHelper::log]
                  setupForm() !!!!
                  S000000000028E000000000743T09:24:17.520W:QObject::setParent: Cannot set parent, new parent is in a different thread
                  S000000000029E000000000743T09:24:17.520DL00000207Fsimon2.js[void clsScriptHelper::log]
                  setupForm() !!!!
                  
                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by
                  #35

                  @SPlatten
                  Perhaps not relevant, but how can you go

                              ptmrScript->moveToThread(pobjScriptEngThread);
                              ptmrScript->setInterval(cuintInterval);
                  

                  Once moved to other thread, are you still allowed to set its interval from this (different) thread?

                  1 Reply Last reply
                  0
                  • SPlattenS SPlatten

                    @kshegunov, this is how it is now:

                    QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                    QThread* pobjScriptEngThread(pobjScriptEng->thread());
                    //Create new timer
                    ptmrScript = new QTimer();
                    ptmrScript->moveToThread(pobjScriptEngThread);
                    ptmrScript->setInterval(cuintInterval);
                    

                    Have just modified to:

                    QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                    QThread* pobjScriptEngThread(pobjScriptEng->thread());
                    //Create new timer
                    ptmrScript = new QTimer();
                    ptmrScript->setParent(pobjScriptEng);
                    ptmrScript->moveToThread(pobjScriptEngThread);
                    ptmrScript->setInterval(cuintInterval);
                    

                    Output is still:

                    S000000000027E000000000743T09:24:17.520DL00000202Fsimon2.js[void clsScriptHelper::log]
                    setupForm() !!!!
                    S000000000028E000000000743T09:24:17.520W:QObject::setParent: Cannot set parent, new parent is in a different thread
                    S000000000029E000000000743T09:24:17.520DL00000207Fsimon2.js[void clsScriptHelper::log]
                    setupForm() !!!!
                    
                    kshegunovK Offline
                    kshegunovK Offline
                    kshegunov
                    Moderators
                    wrote on last edited by
                    #36

                    Okay, I'm getting really tangled. Where is QTimer::start called? In createTimer? If so, then:

                    QTimer timer = new QTimer();
                    ...
                    // Connect the lambda with a context object, as mentioned!
                    ...
                    timer->start();
                    

                    Read and abide by the Qt Code of Conduct

                    SPlattenS 1 Reply Last reply
                    0
                    • kshegunovK kshegunov

                      Okay, I'm getting really tangled. Where is QTimer::start called? In createTimer? If so, then:

                      QTimer timer = new QTimer();
                      ...
                      // Connect the lambda with a context object, as mentioned!
                      ...
                      timer->start();
                      
                      SPlattenS Offline
                      SPlattenS Offline
                      SPlatten
                      wrote on last edited by
                      #37

                      @kshegunov , I'm trying lots of things without taking the time to think about it.

                      Kind Regards,
                      Sy

                      kshegunovK 1 Reply Last reply
                      0
                      • SPlattenS SPlatten

                        @kshegunov , I'm trying lots of things without taking the time to think about it.

                        kshegunovK Offline
                        kshegunovK Offline
                        kshegunov
                        Moderators
                        wrote on last edited by
                        #38

                        @SPlatten said in Help with timer and JavaScript slot.:

                        I'm trying lots of things without taking the time to think about it.

                        Yes, do so. Which is the whole reason I requested the call stack. How am I supposed to guess what calls what ...

                        Read and abide by the Qt Code of Conduct

                        SPlattenS 1 Reply Last reply
                        0
                        • kshegunovK kshegunov

                          @SPlatten said in Help with timer and JavaScript slot.:

                          I'm trying lots of things without taking the time to think about it.

                          Yes, do so. Which is the whole reason I requested the call stack. How am I supposed to guess what calls what ...

                          SPlattenS Offline
                          SPlattenS Offline
                          SPlatten
                          wrote on last edited by
                          #39

                          @kshegunov I would provide the call stack, but execution doesn't halt, so where would you like me to break to then get the stack?

                          Kind Regards,
                          Sy

                          kshegunovK 1 Reply Last reply
                          0
                          • SPlattenS SPlatten

                            @kshegunov, this is how it is now:

                            QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                            QThread* pobjScriptEngThread(pobjScriptEng->thread());
                            //Create new timer
                            ptmrScript = new QTimer();
                            ptmrScript->moveToThread(pobjScriptEngThread);
                            ptmrScript->setInterval(cuintInterval);
                            

                            Have just modified to:

                            QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                            QThread* pobjScriptEngThread(pobjScriptEng->thread());
                            //Create new timer
                            ptmrScript = new QTimer();
                            ptmrScript->setParent(pobjScriptEng);
                            ptmrScript->moveToThread(pobjScriptEngThread);
                            ptmrScript->setInterval(cuintInterval);
                            

                            Output is still:

                            S000000000027E000000000743T09:24:17.520DL00000202Fsimon2.js[void clsScriptHelper::log]
                            setupForm() !!!!
                            S000000000028E000000000743T09:24:17.520W:QObject::setParent: Cannot set parent, new parent is in a different thread
                            S000000000029E000000000743T09:24:17.520DL00000207Fsimon2.js[void clsScriptHelper::log]
                            setupForm() !!!!
                            
                            KroMignonK Offline
                            KroMignonK Offline
                            KroMignon
                            wrote on last edited by KroMignon
                            #40

                            @SPlatten I am always surprised how complicated you are trying to solve common issues.

                            What is the real issue here?
                            You want to create a timer in a specific thread and start it. I am right?
                            QTimer muss be started, and stopped from the owned thread.
                            That's not so complicated to solve:

                            auto myTimer = new  QTimer();
                            connect(myTimer; &QTimer::timeout, ...);
                            // move to thread
                            myTimer->moveToThread(theWorkingThread);
                            
                            // start the timer
                            QTimer::singleShot(0, myTimer, [myTimer]() { myTimer->start(); } );
                            

                            It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

                            SPlattenS 1 Reply Last reply
                            1
                            • KroMignonK KroMignon

                              @SPlatten I am always surprised how complicated you are trying to solve common issues.

                              What is the real issue here?
                              You want to create a timer in a specific thread and start it. I am right?
                              QTimer muss be started, and stopped from the owned thread.
                              That's not so complicated to solve:

                              auto myTimer = new  QTimer();
                              connect(myTimer; &QTimer::timeout, ...);
                              // move to thread
                              myTimer->moveToThread(theWorkingThread);
                              
                              // start the timer
                              QTimer::singleShot(0, myTimer, [myTimer]() { myTimer->start(); } );
                              
                              SPlattenS Offline
                              SPlattenS Offline
                              SPlatten
                              wrote on last edited by SPlatten
                              #41

                              @KroMignon , thank you, will try this now, right now before trying your suggestion the output is:

                              S000000000027E000000000715T09:32:03.904DL00000202Fsimon2.js[void clsScriptHelper::log]
                              setupForm() !!!!
                              S000000000028E000000000715T09:32:03.904DL00000207Fsimon2.js[void clsScriptHelper::log]
                              setupForm() !!!!
                              S000000000029E000000003405T09:32:06.594W:QObject::startTimer: Timers cannot be started from another thread
                              

                              @KroMignon, thank you so much, this now works, here are the prototypes:

                              Q_INVOKABLE void createTimer(const QString& crstrID, const uint cuintInterval
                                                          ,const QString& crstrFunction);
                              Q_INVOKABLE void startTimer(const QString& crstrID);
                              

                              And the final implementations:

                              /**
                               * @brief clsScriptHelper::createTimer
                               * @param crstrID : Constant reference to Timer ID
                               * @param cuintInterval : Constant millisecond interval
                               * @param crstrFunction : Constant reference to JSfile@Function
                               */
                              void clsScriptHelper::createTimer(const QString& crstrID, const uint cuintInterval
                                                               ,const QString& crstrFunction) {
                                  if ( crstrID.trimmed().isEmpty() == true || cuintInterval == 0
                                    || crstrFunction.trimmed().isEmpty() == true
                                    || crstrFunction.indexOf(clsXMLnode::msccScriptDelimiter) == -1 ) {
                                  //One or more of the parameters are invalid, do nothing
                                      return;
                                  }
                                  //Get Application instance
                                  clsMainWnd* pAppInstance(clsMainWnd::pobjGetAppWnd());
                                  if ( pAppInstance == nullptr ) {
                                  //Cannot get application instance!
                                      return;
                                  }
                                  //Look for registered timer
                                  QTimer* ptmrScript(pAppInstance->ptmrGetTimer(crstrID));
                                  if ( ptmrScript != nullptr ) {
                                  //Already registered, do nothing
                                      return;
                                  }
                                  //No timer locatd with that ID, its safe to proceed
                                  QStringList slstScript = crstrFunction.split(clsXMLnode::msccScriptDelimiter);
                                  mpScripts* pmpScriptsMap;
                                  if ( slstScript.length() == SSF_PARAM_COUNT
                                  && (pmpScriptsMap = clsMainWnd::pmpGetScriptsMap()) != nullptr ) {
                                  //Look for the script in the scripts map
                                      mpScripts::iterator itrScript(pmpScriptsMap->find(slstScript[SFF_FILE_IDX]));
                                      if ( itrScript != pmpScriptsMap->end() ) {
                                  //Found it, build the script up ready for the signal connection
                                          QString strScript(itrScript->second);
                                  //Get pointer to script engine
                                          QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                                  //Create new timer
                                          ptmrScript = new QTimer();
                                          ptmrScript->setInterval(cuintInterval);
                                  //Register the new timer using the supplied ID
                                          pAppInstance->registerTimer(ptmrScript, crstrID);
                                  //Add any globals to the script
                                          clsScriptHelper::pobjGetInstance()->addGlobals(pobjScriptEng);
                                  //Build up script function call
                                          QString strFile(slstScript[SFF_FILE_IDX])
                                                 ,strCall(slstScript[SSF_FUNCTION_IDX])
                                                 ,strScriptWithCall(strScript)
                                                 ,strFunc(strCall
                                                        + QString(clsDebugService::msccBrktOpen)
                                                        + QString(clsDebugService::msccBrktClose)
                                                        + QString(clsXMLnode::msccScriptFunctionTerminator));
                                           if ( strScriptWithCall.endsWith(clsXMLnode::msccScriptFunctionTerminator) != true ) {
                                               strScriptWithCall += clsXMLnode::msccScriptFunctionTerminator;
                                           }
                                           strScriptWithCall += strFunc;
                                  //Create connection to timer and script
                                           QMetaObject::Connection cn = QObject::connect(ptmrScript
                                                                                       ,&QTimer::timeout
                                                                                       ,pobjScriptEng
                                                                                       ,[pobjScriptEng
                                                                                        ,ptmrScript
                                                                                        ,strFile
                                                                                        ,strFunc
                                                                                        ,strScriptWithCall]() {
                                               QJSValue objResult(pobjScriptEng->evaluate(strScriptWithCall));
                                               QString strError;
                                               if ( objResult.isError() == true ) {
                                                   strError = QString("%1\n%2\n%3").arg(strFile).arg(strFunc)
                                                                                   .arg(objResult.toString());
                                               } else {
                                                   QString strResult(objResult.toString());
                                                   if ( strResult.compare("undefined") != 0 ) {
                                                       strError = strResult;
                                                   }
                                               }
                                               if ( strError.isEmpty() != true ) {
                                                   clsXMLnode* pobjRoot(clsXMLnode::spobjGetRoot());
                                                   emit pobjRoot->error(strError);
                                                   ptmrScript->deleteLater();
                                               }
                                          });
                                          QThread* pobjScriptEngThread(pobjScriptEng->thread());
                                          ptmrScript->moveToThread(pobjScriptEngThread);
                                      }
                                  }
                              }
                              /**
                               * @brief clsScriptHelper::startTimer
                               * @param crstrID : Constant reference to timer ID
                               */
                              void clsScriptHelper::startTimer(const QString& crstrID) {
                                  //Get Application instance
                                  clsMainWnd* pAppInstance(clsMainWnd::pobjGetAppWnd());
                                  if ( pAppInstance == nullptr ) {
                                  //Cannot get application instance!
                                      return;
                                  }
                                  QTimer* ptmrScript(pAppInstance->ptmrGetTimer(crstrID));
                                  if ( ptmrScript != nullptr ) {
                                      QTimer::singleShot(0, ptmrScript, [ptmrScript]() { ptmrScript->start(); } );
                                  }
                              }
                              

                              Kind Regards,
                              Sy

                              KroMignonK 1 Reply Last reply
                              0
                              • SPlattenS SPlatten

                                @kshegunov I would provide the call stack, but execution doesn't halt, so where would you like me to break to then get the stack?

                                kshegunovK Offline
                                kshegunovK Offline
                                kshegunov
                                Moderators
                                wrote on last edited by
                                #42

                                @SPlatten said in Help with timer and JavaScript slot.:

                                I would provide the call stack, but execution doesn't halt, so where would you like me to break to then get the stack?

                                Before doing the connect for the timer timeout. Provide the following things (in one post please):

                                1. The whole source of the enclosing function.
                                2. The call stack.
                                3. The output of this added just before doing the connect:
                                qDebug() << ptmrScript->thread() << QThread::currentThread() << ptmrScript->parent();
                                

                                Read and abide by the Qt Code of Conduct

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                                • SPlattenS SPlatten

                                  @KroMignon , thank you, will try this now, right now before trying your suggestion the output is:

                                  S000000000027E000000000715T09:32:03.904DL00000202Fsimon2.js[void clsScriptHelper::log]
                                  setupForm() !!!!
                                  S000000000028E000000000715T09:32:03.904DL00000207Fsimon2.js[void clsScriptHelper::log]
                                  setupForm() !!!!
                                  S000000000029E000000003405T09:32:06.594W:QObject::startTimer: Timers cannot be started from another thread
                                  

                                  @KroMignon, thank you so much, this now works, here are the prototypes:

                                  Q_INVOKABLE void createTimer(const QString& crstrID, const uint cuintInterval
                                                              ,const QString& crstrFunction);
                                  Q_INVOKABLE void startTimer(const QString& crstrID);
                                  

                                  And the final implementations:

                                  /**
                                   * @brief clsScriptHelper::createTimer
                                   * @param crstrID : Constant reference to Timer ID
                                   * @param cuintInterval : Constant millisecond interval
                                   * @param crstrFunction : Constant reference to JSfile@Function
                                   */
                                  void clsScriptHelper::createTimer(const QString& crstrID, const uint cuintInterval
                                                                   ,const QString& crstrFunction) {
                                      if ( crstrID.trimmed().isEmpty() == true || cuintInterval == 0
                                        || crstrFunction.trimmed().isEmpty() == true
                                        || crstrFunction.indexOf(clsXMLnode::msccScriptDelimiter) == -1 ) {
                                      //One or more of the parameters are invalid, do nothing
                                          return;
                                      }
                                      //Get Application instance
                                      clsMainWnd* pAppInstance(clsMainWnd::pobjGetAppWnd());
                                      if ( pAppInstance == nullptr ) {
                                      //Cannot get application instance!
                                          return;
                                      }
                                      //Look for registered timer
                                      QTimer* ptmrScript(pAppInstance->ptmrGetTimer(crstrID));
                                      if ( ptmrScript != nullptr ) {
                                      //Already registered, do nothing
                                          return;
                                      }
                                      //No timer locatd with that ID, its safe to proceed
                                      QStringList slstScript = crstrFunction.split(clsXMLnode::msccScriptDelimiter);
                                      mpScripts* pmpScriptsMap;
                                      if ( slstScript.length() == SSF_PARAM_COUNT
                                      && (pmpScriptsMap = clsMainWnd::pmpGetScriptsMap()) != nullptr ) {
                                      //Look for the script in the scripts map
                                          mpScripts::iterator itrScript(pmpScriptsMap->find(slstScript[SFF_FILE_IDX]));
                                          if ( itrScript != pmpScriptsMap->end() ) {
                                      //Found it, build the script up ready for the signal connection
                                              QString strScript(itrScript->second);
                                      //Get pointer to script engine
                                              QJSEngine* pobjScriptEng(clsJSON::pobjGetScriptEng());
                                      //Create new timer
                                              ptmrScript = new QTimer();
                                              ptmrScript->setInterval(cuintInterval);
                                      //Register the new timer using the supplied ID
                                              pAppInstance->registerTimer(ptmrScript, crstrID);
                                      //Add any globals to the script
                                              clsScriptHelper::pobjGetInstance()->addGlobals(pobjScriptEng);
                                      //Build up script function call
                                              QString strFile(slstScript[SFF_FILE_IDX])
                                                     ,strCall(slstScript[SSF_FUNCTION_IDX])
                                                     ,strScriptWithCall(strScript)
                                                     ,strFunc(strCall
                                                            + QString(clsDebugService::msccBrktOpen)
                                                            + QString(clsDebugService::msccBrktClose)
                                                            + QString(clsXMLnode::msccScriptFunctionTerminator));
                                               if ( strScriptWithCall.endsWith(clsXMLnode::msccScriptFunctionTerminator) != true ) {
                                                   strScriptWithCall += clsXMLnode::msccScriptFunctionTerminator;
                                               }
                                               strScriptWithCall += strFunc;
                                      //Create connection to timer and script
                                               QMetaObject::Connection cn = QObject::connect(ptmrScript
                                                                                           ,&QTimer::timeout
                                                                                           ,pobjScriptEng
                                                                                           ,[pobjScriptEng
                                                                                            ,ptmrScript
                                                                                            ,strFile
                                                                                            ,strFunc
                                                                                            ,strScriptWithCall]() {
                                                   QJSValue objResult(pobjScriptEng->evaluate(strScriptWithCall));
                                                   QString strError;
                                                   if ( objResult.isError() == true ) {
                                                       strError = QString("%1\n%2\n%3").arg(strFile).arg(strFunc)
                                                                                       .arg(objResult.toString());
                                                   } else {
                                                       QString strResult(objResult.toString());
                                                       if ( strResult.compare("undefined") != 0 ) {
                                                           strError = strResult;
                                                       }
                                                   }
                                                   if ( strError.isEmpty() != true ) {
                                                       clsXMLnode* pobjRoot(clsXMLnode::spobjGetRoot());
                                                       emit pobjRoot->error(strError);
                                                       ptmrScript->deleteLater();
                                                   }
                                              });
                                              QThread* pobjScriptEngThread(pobjScriptEng->thread());
                                              ptmrScript->moveToThread(pobjScriptEngThread);
                                          }
                                      }
                                  }
                                  /**
                                   * @brief clsScriptHelper::startTimer
                                   * @param crstrID : Constant reference to timer ID
                                   */
                                  void clsScriptHelper::startTimer(const QString& crstrID) {
                                      //Get Application instance
                                      clsMainWnd* pAppInstance(clsMainWnd::pobjGetAppWnd());
                                      if ( pAppInstance == nullptr ) {
                                      //Cannot get application instance!
                                          return;
                                      }
                                      QTimer* ptmrScript(pAppInstance->ptmrGetTimer(crstrID));
                                      if ( ptmrScript != nullptr ) {
                                          QTimer::singleShot(0, ptmrScript, [ptmrScript]() { ptmrScript->start(); } );
                                      }
                                  }
                                  
                                  KroMignonK Offline
                                  KroMignonK Offline
                                  KroMignon
                                  wrote on last edited by
                                  #43

                                  @SPlatten said in Help with timer and JavaScript slot.:

                                  right now before trying your suggestion the output is:

                                     setupForm() !!!!
                                     S000000000029E000000003405T09:32:06.594W:QObject::startTimer: Timers cannot be started from another thread
                                  

                                  Same issue, you are trying to start a QTimer from the wrong thread.
                                  QTimer::singleShot(0, myTimer, [myTimer]() { myTimer->start(); } ); will solve this.

                                  It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

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