This yields a second or so speedup in unused, find, etc. Seems that even
when the ByteString is immediately split and then converted to Strings,
it's faster.
I may try to push ByteStrings out into more of git-annex gradually,
although I suspect most of the time-critical parts are already covered
now, and many of the rest rely on libraries that only support Strings.
Added Git.ByteString which replaces Git IO methods with ones using lazy
ByteStrings. This can be more efficient when large quantities of data are
being read from git.
In Git.LsTree, parse git ls-tree output more efficiently, thanks
to ByteString. This benchmarks 25% faster, in a benchmark that includes
(probably predominately) the run time for git ls-tree itself.
In real world numbers, this makes git annex unused 2 seconds faster for
each branch it needs to check, in my usual large repo.
Fixed the laziness space leak, so it runs in 60 mb or so again. Slightly
faster due to using Data.Set.difference now, although this also makes it
use slightly more memory.
Also added display of the refs being checked, and made unused --from
also check all refs for things in the remote.
Using Sets is the right thing; they have constant size lookup like my
SizeList, and logn insertation, which beats nub to death.
Runs faster than --fast mode did before, and gives accurate counts.
13 seconds total runtime with a warm cache in a repository with 40 thousand
keys.
Do not need to check the location log in this case, can just check inAnnex.
This is both an optimisation and perhaps a correctness measure
(fsck --in . should fsck files even if the location log is damaged.)
filterM is not a good idea if you were streaming in a large list of files.
Fixing this memory leak that I introduced earlier today was a PITA because
to avoid the filterM, it's necessary to do the filtering only after
building up the data structures like BackendFile, and that means each
separate data structure needs it own function to apply the filter,
at least in this naive implementation.
There is also a minor performance regression, when using copy/drop/get/fsck
with a filter, git is now asked to look up attributes for all files,
since that now comes before the filter is applied. This is only a very
minor thing, since getting the attributes is very fast and --exclude was
probably not typically used to speed it up.
