assert (joinable) before joining threads; fix possible crash after cancelling jobs.

diff --git a/src/lib/job.cc b/src/lib/job.cc
index 439000e5876dcc61b061c8ddbfdf6645be026905..7aaac748c115a1d9e65144027e7eacf96f1d6640 100644 (file)
--- a/src/lib/job.cc
+++ b/src/lib/job.cc
@@ -59,6 +59,7 @@ Job::~Job ()
 {
        if (_thread) {
                _thread->interrupt ();
+               DCPOMATIC_ASSERT (_thread->joinable ());
                _thread->join ();
        }
 
@@ -416,7 +417,10 @@ Job::cancel ()
        }
 
        _thread->interrupt ();
+       DCPOMATIC_ASSERT (_thread->joinable ());
        _thread->join ();
+       delete _thread;
+       _thread = 0;
 }
 
 void