Fix deadlock on cancelling jobs.v2.16.21

1 files changed, 10 insertions, 1 deletions

diff --git a/src/tools/dcpomatic.cc b/src/tools/dcpomatic.cc
index 6f55b1771..57fad5a0a 100644
--- a/src/tools/dcpomatic.cc
+++ b/src/tools/dcpomatic.cc
@@ -372,7 +372,7 @@ public:
 		_film_editor->content_panel()->SelectionChanged.connect (boost::bind (&DOMFrame::set_menu_sensitivity, this));
 		set_title ();
 
-		JobManager::instance()->ActiveJobsChanged.connect (boost::bind (&DOMFrame::set_menu_sensitivity, this));
+		JobManager::instance()->ActiveJobsChanged.connect(boost::bind(&DOMFrame::active_jobs_changed, this));
 
 		overall_panel->SetSizer (main_sizer);
 
@@ -1200,6 +1200,15 @@ private:
 		ev.Skip ();
 	}
 
+	void active_jobs_changed()
+	{
+		/* ActiveJobsChanged can be called while JobManager holds a lock on its mutex, making
+		 * the call to JobManager::get() in set_menu_sensitivity() deadlock unless we work around
+		 * it by using an idle callback.  This feels quite unpleasant.
+		 */
+		signal_manager->when_idle(boost::bind(&DOMFrame::set_menu_sensitivity, this));
+	}
+
 	void set_menu_sensitivity ()
 	{
 		auto jobs = JobManager::instance()->get ();