From cfa822570e6f2d2d09fe1c36a81b224ded07c6b6 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Sun, 5 Jul 2020 22:10:03 +0200
Subject: [PATCH] Improve butler error reporting during export.

---
 src/lib/butler.cc         | 8 +++++++-
 src/lib/butler.h          | 4 +++-
 src/lib/ffmpeg_encoder.cc | 1 +
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/lib/butler.cc b/src/lib/butler.cc
index 20180330e..595d98809 100644
--- a/src/lib/butler.cc
+++ b/src/lib/butler.cc
@@ -238,7 +238,13 @@ Butler::get_video (bool blocking, Error* e)
 
 	if (_video.empty()) {
 		if (e) {
-			*e = NONE;
+			if (_died) {
+				*e = DIED;
+			} else if (_finished) {
+				*e = FINISHED;
+			} else {
+				*e = NONE;
+			}
 		}
 		return make_pair(shared_ptr<PlayerVideo>(), DCPTime());
 	}
diff --git a/src/lib/butler.h b/src/lib/butler.h
index ce3c9ae48..6263d6143 100644
--- a/src/lib/butler.h
+++ b/src/lib/butler.h
@@ -51,7 +51,9 @@ public:
 
 	enum Error {
 		NONE,
-		AGAIN
+		AGAIN,
+		DIED,
+		FINISHED
 	};
 
 	std::pair<boost::shared_ptr<PlayerVideo>, dcpomatic::DCPTime> get_video (bool blocking, Error* e = 0);
diff --git a/src/lib/ffmpeg_encoder.cc b/src/lib/ffmpeg_encoder.cc
index ee49a0646..15e27e633 100644
--- a/src/lib/ffmpeg_encoder.cc
+++ b/src/lib/ffmpeg_encoder.cc
@@ -166,6 +166,7 @@ FFmpegEncoder::go ()
 		for (int j = 0; j < gets_per_frame; ++j) {
 			Butler::Error e;
 			pair<shared_ptr<PlayerVideo>, DCPTime> v = _butler->get_video (true, &e);
+			_butler->rethrow ();
 			if (!v.first) {
 				throw ProgrammingError(__FILE__, __LINE__, String::compose("butler returned no video; error was %1", static_cast<int>(e)));
 			}
-- 
2.30.2