Another writer deadlock fix.

diff --git a/src/lib/writer.cc b/src/lib/writer.cc
index 8ee6293094c1397d58ef8a7384a94cde58aff9d4..96fb9e179cc30b76ae5815899c4bf2f86187339f 100644 (file)
--- a/src/lib/writer.cc
+++ b/src/lib/writer.cc
@@ -173,8 +173,10 @@ Writer::repeat (Frame frame, Eyes eyes)
 {
        boost::mutex::scoped_lock lock (_state_mutex);
 
-       while (_queue.size() > _maximum_queue_size) {
-               /* The queue is too big; wait until that is sorted out */
+       while (_queue.size() > _maximum_queue_size && have_sequenced_image_at_queue_head()) {
+               /* The queue is too big, and the main writer thread can run and fix it, so
+                  wait until it has done.
+               */
                _full_condition.wait (lock);
        }
 
@@ -201,12 +203,9 @@ Writer::fake_write (Frame frame, Eyes eyes)
 {
        boost::mutex::scoped_lock lock (_state_mutex);
 
-       while (_queue.size() > _maximum_queue_size) {
-               /* The queue is too big; wait until that is sorted out.  We're assuming here
-                  that it will be sorted out either by time or by a necessary full-written
-                  frame being given to us.  fake_write() must be called more-or-less in
-                  order or this will deadlock due to the main write thread waiting for
-                  a frame that never arrives because we're waiting here.
+       while (_queue.size() > _maximum_queue_size && have_sequenced_image_at_queue_head()) {
+               /* The queue is too big, and the main writer thread can run and fix it, so
+                  wait until it has done.
                */
                _full_condition.wait (lock);
        }