3 files changed, 35 insertions, 0 deletions
diff --git a/src/lib/j2k_encoder.cc b/src/lib/j2k_encoder.cc
index 7c9777c16..32d2fefc2 100644
--- a/src/lib/j2k_encoder.cc
+++ b/src/lib/j2k_encoder.cc
@@ -69,6 +69,16 @@ J2KEncoder::~J2KEncoder ()
 {
 	_server_found_connection.disconnect();
 
+	/* One of our encoder threads may be waiting on Writer::write() to return, if that method
+	 * is blocked with the writer queue full waiting for _full_condition.  In that case, the
+	 * attempt to terminate the encoder threads below (in terminate_threads()) will fail because
+	 * the encoder thread waiting for ::write() will have interruption disabled.
+	 *
+	 * To work around that, make the writer into a zombie to unblock any pending write()s and
+	 * not block on any future ones.
+	 */
+	_writer.zombify();
+
 	boost::mutex::scoped_lock lm (_threads_mutex);
 	terminate_threads ();
 }
diff --git a/src/lib/writer.cc b/src/lib/writer.cc
index fbe2d248d..7b9defd73 100644
--- a/src/lib/writer.cc
+++ b/src/lib/writer.cc
@@ -144,6 +144,10 @@ Writer::write (shared_ptr<const Data> encoded, Frame frame, Eyes eyes)
 {
 	boost::mutex::scoped_lock lock (_state_mutex);
 
+	if (_zombie) {
+		return;
+	}
+
 	while (_queued_full_in_memory > _maximum_frames_in_memory) {
 		/* There are too many full frames in memory; wake the main writer thread and
 		   wait until it sorts everything out */
@@ -377,6 +381,9 @@ try
 	while (true)
 	{
 		boost::mutex::scoped_lock lock (_state_mutex);
+		if (_zombie) {
+			return;
+		}
 
 		while (true) {
 
@@ -1042,3 +1049,17 @@ Writer::write_hanging_text (ReelWriter& reel)
 	}
 	_hanging_texts = new_hanging_texts;
 }
+
+
+/** Set the writer so that it has no queue and drops any pending or future requests to write images */
+void
+Writer::zombify()
+{
+	boost::mutex::scoped_lock lock(_state_mutex);
+
+	_queue.clear();
+	_queued_full_in_memory = 0;
+	_zombie = true;
+	_full_condition.notify_all();
+}
+
diff --git a/src/lib/writer.h b/src/lib/writer.h
index 6e7f5ca90..f0f1fe69a 100644
--- a/src/lib/writer.h
+++ b/src/lib/writer.h
@@ -127,6 +127,8 @@ public:
 
 	void set_encoder_threads (int threads);
 
+	void zombify();
+
 private:
 	friend struct ::writer_disambiguate_font_ids1;
 	friend struct ::writer_disambiguate_font_ids2;
@@ -229,6 +231,8 @@ private:
 	};
 
 	std::vector<HangingText> _hanging_texts;
+
+	bool _zombie = false;
 };