Give ownership of info files to ReelWriters (#2912).v2.18.2

The motivation here is to stop a pattern where we create a file, close
it, and then re-open it (many times) as I think there are problems on
Windows when a virus scanner sees the new file, opens it for checking,
and then we can't re-open it.

This also makes things a fair bit simpler, as a lock is removed and we
don't try to differentiate read/write cases by opening the file in
different ways; it's now always writeable.

1 files changed, 9 insertions, 3 deletions

diff --git a/src/lib/frame_info.h b/src/lib/frame_info.h
index a5a22bd9e..da9503248 100644
--- a/src/lib/frame_info.h
+++ b/src/lib/frame_info.h
@@ -29,9 +29,15 @@ class J2KFrameInfo : public dcp::J2KFrameInfo
 public:
 	J2KFrameInfo(dcp::J2KFrameInfo const& info);
 	J2KFrameInfo(uint64_t offset_, uint64_t size_, std::string hash_);
-	J2KFrameInfo(std::shared_ptr<InfoFileHandle> info_file, Frame frame, Eyes eyes);
-
-	void write(std::shared_ptr<InfoFileHandle> info_file, Frame frame, Eyes eyes) const;
+	/** Seek to the required position in info_file and read the info for
+	 *  the given frame and eyes.
+	 */
+	J2KFrameInfo(dcp::File& info_file, Frame frame, Eyes eyes);
+
+	/** Seek to the required position in info_file and write the info for
+	 *  the given frame and eyes.
+	 */
+	void write(dcp::File& info_file, Frame frame, Eyes eyes) const;
 
 	static int size_on_disk() {
 		return _size_on_disk;