statusbar: disconnect old task when connecting a new one

app/window/mainwindow/mainstatusbar.cpp

@@ -26,7 +26,8 @@ OLIVE_NAMESPACE_ENTER
 
 MainStatusBar::MainStatusBar(QWidget *parent) :
   QStatusBar(parent),
-  manager_(nullptr)
+  manager_(nullptr),
+  connected_task_(nullptr)
 {
   setSizeGripEnabled(false);
 
@@ -37,7 +38,8 @@ MainStatusBar::MainStatusBar(QWidget *parent) :
   bar_->setMaximum(100);
   bar_->setVisible(false);
 
-  showMessage(tr("Welcome to %1 %2").arg(QCoreApplication::applicationName(), QCoreApplication::applicationVersion()));
+  showMessage(tr("Welcome to %1 %2").arg(QCoreApplication::applicationName(),
+                                         QCoreApplication::applicationVersion()));
 }
 
 void MainStatusBar::ConnectTaskManager(TaskManager *manager)
@@ -73,7 +75,15 @@ void MainStatusBar::UpdateStatus()
     }
 
     bar_->setVisible(true);
-    connect(t, &Task::ProgressChanged, this, &MainStatusBar::SetProgressBarValue);
+
+    if (connected_task_) {
+      disconnect(connected_task_, &Task::ProgressChanged, this, &MainStatusBar::SetProgressBarValue);
+      disconnect(connected_task_, &Task::destroyed, this, &MainStatusBar::ConnectedTaskDeleted);
+    }
+
+    connected_task_ = t;
+    connect(connected_task_, &Task::ProgressChanged, this, &MainStatusBar::SetProgressBarValue);
+    connect(connected_task_, &Task::destroyed, this, &MainStatusBar::ConnectedTaskDeleted);
   }
 }
 
@@ -82,6 +92,11 @@ void MainStatusBar::SetProgressBarValue(double d)
   bar_->setValue(qRound(100.0 * d));
 }
 
+void MainStatusBar::ConnectedTaskDeleted()
+{
+  connected_task_ = nullptr;
+}
+
 void MainStatusBar::mouseDoubleClickEvent(QMouseEvent* e)
 {
   QStatusBar::mouseDoubleClickEvent(e);

app/window/mainwindow/mainstatusbar.h

@@ -50,11 +50,15 @@ private slots:
 
   void SetProgressBarValue(double d);
 
+  void ConnectedTaskDeleted();
+
 private:
   TaskManager* manager_;
 
   QProgressBar* bar_;
 
+  Task* connected_task_;
+
 };
 
 OLIVE_NAMESPACE_EXIT