This turns out to be possible after all, because the old one decomposed
a unicode Char to multiple Word8s and encoded those. It should be faster
in some places, particularly in Git.Filename.encodeAlways.
The old version encoded all unicode by default as well as ascii control
characters and also '"'. The new one only encodes ascii control
characters by default.
That old behavior was visible in Utility.Format.format, which did escape
'"' when used in eg git-annex find --format='${escaped_file}\n'
So made sure to keep that working the same. Although the man page only
says it will escape "unusual" characters, so it might be able to be
changed.
Git.Filename.encodeAlways also needs to escape '"' ; that was the
original reason that was escaped.
Types.Transferrer I judge is ok to not escape '"', because the escaped
value is sent in a line-based protocol, which is decoded at the other
end by decode_c. So old git-annex and new will be fine whether that is
escaped or not, the result will be the same.
Note that when asked to escape a double quote, it is escaped to \"
rather than to \042. That's the same behavior as git has. It's
perhaps somehow more of a special case than it needs to be.
Sponsored-by: k0ld on Patreon
This speeds up a few things, notably CmdLine.Seek using Git.Filename
which uses decode_c and this avoids a conversion to String and back,
and probably the ByteString implementation of decode_c is also faster
for simple cases at least than the string version.
encode_c cannot be converted to ByteString (or if it did, it would have
to convert right back to String in order to handle unicode).
Sponsored-by: Brock Spratlen on Patreon
Rather than using Read/Show, which would force me to preserve data types
into the future.
I considered just deriving json and sending that, but I don't much like
deriving json with data types that have named constructors (like Key
does) because again it locks in data type details.
So instead, used SimpleProtocol, with a fairly complex and unreadable
protocol. But it is as efficient as the p2p protocol at least, and as
future proof.
(Writing my own custom json instances would have worked but I thought
of it too late and don't want to do all the work twice. The only real
benefit might be that aeson could be faster.)
Note that, when a new protocol request type is added later, git-annex
trying to use it will cause the git-annex transferrer to display a
protocol error message. That seems ok; it would only happen if a new
git-annex found an old version of itself in PATH or the program
file. So it's unlikely, and all it can do anyway is display an error.
(The error message could perhaps be improved..)
This commit was sponsored by Jack Hill on Patreon.
