Fix corruption of an existing DCP when a new one is made with the same video

asset (#1126).

diff --git a/src/lib/reel_writer.cc b/src/lib/reel_writer.cc
index fde977c3a97838e4247c603ec80de9eabe097c3c..10d405961ad4af041128e72a9a3e39a6ee57fa0c 100644 (file)
--- a/src/lib/reel_writer.cc
+++ b/src/lib/reel_writer.cc
@@ -197,14 +197,26 @@ ReelWriter::frame_info_position (Frame frame, Eyes eyes) const
 Frame
 ReelWriter::check_existing_picture_asset ()
 {
-       /* Try to open the existing asset */
        DCPOMATIC_ASSERT (_picture_asset->file());
-       FILE* asset_file = fopen_boost (_picture_asset->file().get(), "rb");
+       boost::filesystem::path asset = _picture_asset->file().get();
+
+       /* If there is an existing asset, break any hard links to it as we are about to change its contents
+          (if only by changing the IDs); see #1126.
+       */
+
+       if (boost::filesystem::exists(asset) && boost::filesystem::hard_link_count(asset) > 1) {
+               boost::filesystem::copy_file (asset, asset.string() + ".tmp");
+               boost::filesystem::remove (asset);
+               boost::filesystem::rename (asset.string() + ".tmp", asset);
+       }
+
+       /* Try to open the existing asset */
+       FILE* asset_file = fopen_boost (asset, "rb");
        if (!asset_file) {
-               LOG_GENERAL ("Could not open existing asset at %1 (errno=%2)", _picture_asset->file()->string(), errno);
+               LOG_GENERAL ("Could not open existing asset at %1 (errno=%2)", asset.string(), errno);
                return 0;
        } else {
-               LOG_GENERAL ("Opened existing asset at %1", _picture_asset->file()->string());
+               LOG_GENERAL ("Opened existing asset at %1", asset.string());
        }
 
        /* Offset of the last dcp::FrameInfo in the info file */

diff --git a/test/remake_id_test.cc b/test/remake_id_test.cc
new file mode 100644 (file)
index 0000000..d8bb5df
--- /dev/null
+++ b/test/remake_id_test.cc
@@ -0,0 +1,55 @@
+/*
+    Copyright (C) 2017 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DCP-o-matic is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include "lib/ffmpeg_content.h"
+#include "lib/content_factory.h"
+#include "lib/subtitle_content.h"
+#include "lib/film.h"
+#include "test.h"
+#include <boost/test/unit_test.hpp>
+
+using boost::shared_ptr;
+using boost::dynamic_pointer_cast;
+
+/** Check for bug #1126 whereby making a new DCP using the same video asset as an old one
+ *  corrupts the old one.
+ */
+BOOST_AUTO_TEST_CASE (remake_id_test)
+{
+       /* Make a DCP */
+       shared_ptr<Film> film = new_test_film2 ("remake_id_test");
+       shared_ptr<Content> content = content_factory(film, "test/data/flat_red.png").front();
+       film->examine_and_add_content (content);
+       BOOST_REQUIRE (!wait_for_jobs ());
+       film->make_dcp ();
+       BOOST_REQUIRE (!wait_for_jobs ());
+
+       /* Copy the video file */
+       boost::filesystem::path first_video = video_file(film);
+       boost::filesystem::copy_file (first_video, first_video.string() + ".copy");
+
+       /* Make a new DCP with the same video file */
+       film->set_name ("remake_id_test2");
+       film->make_dcp ();
+       BOOST_REQUIRE (!wait_for_jobs ());
+
+       /* Check that the video in the first DCP hasn't changed */
+       check_file (first_video, first_video.string() + ".copy");
+}

diff --git a/test/wscript b/test/wscript
index 6340627cd04266d00a7c42dc77d68e219e1aa965..ecbc32faba96f5800c55d86b61c3ef81f8b8ad4b 100644 (file)
--- a/test/wscript
+++ b/test/wscript
@@ -87,6 +87,7 @@ def build(bld):
                  rect_test.cc
                  reels_test.cc
                  required_disk_space_test.cc
+                 remake_id_test.cc
                  remake_with_subtitle_test.cc
                  render_subtitles_test.cc
                  scaling_test.cc