From 39c880731c36cffd8310ea536509313de9f5fbd6 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Tue, 14 Aug 2018 22:55:06 +0100
Subject: [PATCH] Give filename (where possible) when image file decoding
 fails.

---
 src/lib/magick_image_proxy.cc | 7 ++++++-
 src/lib/magick_image_proxy.h  | 4 ++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/lib/magick_image_proxy.cc b/src/lib/magick_image_proxy.cc
index b12a81db5..cd5749bb6 100644
--- a/src/lib/magick_image_proxy.cc
+++ b/src/lib/magick_image_proxy.cc
@@ -39,6 +39,7 @@ using boost::optional;
 using boost::dynamic_pointer_cast;
 
 MagickImageProxy::MagickImageProxy (boost::filesystem::path path)
+	: _path (path)
 {
 	/* Read the file into a Blob */
 
@@ -101,7 +102,11 @@ MagickImageProxy::image (optional<dcp::NoteHandler>, optional<dcp::Size>) const
 		/* If we failed both an auto-detect and a forced-Targa we give the error from
 		   the auto-detect.
 		*/
-		throw DecodeError (String::compose (_("Could not decode image file (%1)"), error));
+		if (_path) {
+			throw DecodeError (String::compose (_("Could not decode image file %1 (%2)"), _path->string(), error));
+		} else {
+			throw DecodeError (String::compose (_("Could not decode image file (%1)"), error));
+		}
 	}
 
 	unsigned char const * data = static_cast<unsigned char const *>(_blob.data());
diff --git a/src/lib/magick_image_proxy.h b/src/lib/magick_image_proxy.h
index 7d2b69afe..62f3afa2e 100644
--- a/src/lib/magick_image_proxy.h
+++ b/src/lib/magick_image_proxy.h
@@ -42,6 +42,10 @@ public:
 
 private:
 	Magick::Blob _blob;
+	/** Path of a file that this image came from, if applicable; stored so that
+	    failed-decode errors can give more detail.
+	*/
+	boost::optional<boost::filesystem::path> _path;
 	mutable boost::shared_ptr<Image> _image;
 	mutable boost::mutex _mutex;
 };
-- 
2.30.2