Fix what empirically seems to be a double-delete, though I'm not sure how it is.

[dcpomatic.git] / src / lib / signaller.h

diff --git a/src/lib/signaller.h b/src/lib/signaller.h
index 13474ee91baa3eac4e9c7d98042e29f17f68f0aa..a6c74c954feb7eea674e51f608d8235c5feccb34 100644 (file)
--- a/src/lib/signaller.h
+++ b/src/lib/signaller.h
@@ -1,19 +1,20 @@
 /*
     Copyright (C) 2015 Carl Hetherington <cth@carlh.net>
 
-    This program is free software; you can redistribute it and/or modify
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.
 
-    This program is distributed in the hope that it will be useful,
+    DCP-o-matic is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
     You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
 
 */
 
@@ -41,7 +42,17 @@ public:
        }
 
        bool finished () const {
-               boost::mutex::scoped_lock lm (_mutex);
+               boost::mutex::scoped_lock lm (_mutex, boost::try_to_lock);
+               if (!lm) {
+                       /* It's possible that emission of this
+                          wrapper's signal causes another signal to
+                          be emitted, which causes finished() on this
+                          wrapper to be called (by Signaller::emit).
+                          In this case, just say that the wrapper is
+                          not yet finished.
+                       */
+                       return false;
+               }
                return _finished;
        }