Fix #970 by making sure the session state handler can be called

Before, the session did call Session::stop_capture() and fired
the signal to notify of its capture state change. However, the
Session object was deleted before the next run of the Qt event
loop. As the Qt event loop dismisses signals originating from
deleted objects, the connected event handler
MainWindow::on_capture_state_changed() was never called.

To remedy this, we call Session::stop_capture() before the
destruction of the object and force a run of the event loop
immediately afterwards. This way, the event handler is called
and the run/stop button updated properly.

diff --git a/pv/mainwindow.cpp b/pv/mainwindow.cpp
index a20f12a6712a087522ab45d6d770e0fba668fe03..9a3f197d4c2174edd3a9b814b9b340d1fc695fce 100644 (file)
--- a/pv/mainwindow.cpp
+++ b/pv/mainwindow.cpp
@@ -303,8 +303,18 @@ shared_ptr<Session> MainWindow::add_session()
 
 void MainWindow::remove_session(shared_ptr<Session> session)
 {
+       // Determine the height of the button before it collapses
        int h = new_session_button_->height();
 
+       // Stop capture while the session still exists so that the UI can be
+       // updated in case we're currently running. If so, this will schedule a
+       // call to our on_capture_state_changed() slot for the next run of the
+       // event loop. We need to have this executed immediately or else it will
+       // be dismissed since the session object will be deleted by the time we
+       // leave this method and the event loop gets a chance to run again.
+       session->stop_capture();
+       QApplication::processEvents();
+
        for (shared_ptr<views::ViewBase> view : session->views())
                remove_view(view);
 
@@ -316,6 +326,7 @@ void MainWindow::remove_session(shared_ptr<Session> session)
        if (last_focused_session_ == session)
                last_focused_session_.reset();
 
+       // Remove the session from our list of sessions (which also destroys it)
        sessions_.remove_if([&](shared_ptr<Session> s) {
                return s == session; });