git/contrib
SZEDER Gábor e896369beb completion: let 'for-each-ref' and 'ls-remote' filter matching refs
When completing refs, several __git_refs() code paths list all the
refs from the refs/{heads,tags,remotes}/ hierarchy and then
__gitcomp_nl() iterates over those refs in a shell loop to filter out
refs not matching the current ref to be completed.  This comes with a
considerable performance penalty when a repository contains a lot of
refs but the current ref can be uniquely completed or when only a
handful of refs match the current ref.

Reduce the number of iterations in __gitcomp_nl() from the number of
refs to the number of matching refs by specifying appropriate globbing
patterns to 'git for-each-ref' and 'git ls-remote' to list only those
refs that match the current ref to be completed.  However, do so only
when the ref to match is explicitly given as parameter, because the
current word on the command line might contain a prefix like
'--option=' or 'branch..'.  The __git_complete_refs() and
__git_complete_fetch_refspecs() helpers introduced previously in this
patch series already call __git_refs() specifying this current ref
parameter, so all their callsites, i.e. all places in the completion
script doing refs completion, can benefit from this optimization.

Furthermore, list only those symbolic and pseudo refs that match the
current ref to be completed.  Though it doesn't matter at all in
itself performance-wise, it will allow us further significant
optimizations later in this series.

This speeds up refs completion considerably when there are a lot of
non-matching refs to be filtered out.  Uniquely completing a branch in
a repository with 100k local branches, all packed, best of five:

  On Linux, before:

    $ time __git_complete_refs --cur=maste

    real    0m0.831s
    user    0m0.808s
    sys     0m0.028s

  After:

    real    0m0.119s
    user    0m0.104s
    sys     0m0.008s

  On Windows, before:

    real    0m1.480s
    user    0m1.031s
    sys     0m0.060s

  After:

    real    0m0.377s
    user    0m0.015s
    sys     0m0.030s

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-23 11:18:22 -07:00
..
buildsystems mark Windows build scripts executable 2013-11-25 15:01:22 -08:00
coccinelle Merge branch 'rs/absolute-pathdup' 2017-02-02 13:36:55 -08:00
completion completion: let 'for-each-ref' and 'ls-remote' filter matching refs 2017-03-23 11:18:22 -07:00
contacts contacts: add a Makefile to generate docs and install 2014-10-15 15:18:27 -07:00
credential Merge branch 'mm/credential-libsecret' 2016-10-26 13:14:45 -07:00
diff-highlight diff-highlight: avoid highlighting combined diffs 2016-08-31 09:59:53 -07:00
emacs emacs: make 'git-status' work with separate git dirs 2012-11-26 09:34:28 -08:00
examples Merge branch 'js/difftool-builtin' 2017-01-31 13:15:00 -08:00
fast-import import-tars: support hard links 2016-08-03 09:46:11 -07:00
git-jump contrib/git-jump: fix typo in README 2016-07-22 12:34:51 -07:00
git-shell-commands Add sample commands for git-shell 2010-08-12 15:16:31 -07:00
hg-to-git hg-to-git: --allow-empty-message in git commit 2013-07-23 12:17:23 -07:00
hooks git-multimail: update to release 1.4.0 2016-08-17 11:36:08 -07:00
long-running-filter docs: warn about possible '=' in clean/smudge filter process values 2016-12-06 11:29:52 -08:00
mw-to-git Spelling fixes 2016-08-11 14:35:42 -07:00
persistent-https contrib/persistent-https: use Git version for build label 2016-07-22 10:59:03 -07:00
remote-helpers Revert "Merge branch 'jc/graduate-remote-hg-bzr' (early part)" 2014-05-20 14:48:11 -07:00
stats contrib: update stats/mailmap script 2012-12-12 11:09:11 -08:00
subtree Spelling fixes 2016-08-11 14:35:42 -07:00
svn-fe contrib/svn-fe: fix Makefile 2014-08-28 15:41:28 -07:00
thunderbird-patch-inline contrib/thunderbird-patch-inline/appp.sh: use the $( ... ) construct for command substitution 2015-12-27 15:33:13 -08:00
update-unicode update_unicode.sh: remove the plane filter 2016-12-14 09:48:07 -08:00
workdir git-new-workdir: don't fail if the target directory is empty 2014-12-03 12:49:24 -08:00
convert-grafts-to-replace-refs.sh contrib: add convert-grafts-to-replace-refs.sh 2014-07-21 12:05:53 -07:00
git-resurrect.sh git-sh-setup.sh: add variable to use the stuck-long mode 2014-02-03 12:11:10 -08:00
README
remotes2config.sh contrib: Make remotes2config.sh script more robust 2007-12-04 14:35:08 -08:00
rerere-train.sh Escape Git's exec path in contrib/rerere-train.sh script 2015-11-20 06:43:00 -05:00

Contributed Software

Although these pieces are available as part of the official git
source tree, they are in somewhat different status.  The
intention is to keep interesting tools around git here, maybe
even experimental ones, to give users an easier access to them,
and to give tools wider exposure, so that they can be improved
faster.

I am not expecting to touch these myself that much.  As far as
my day-to-day operation is concerned, these subdirectories are
owned by their respective primary authors.  I am willing to help
if users of these components and the contrib/ subtree "owners"
have technical/design issues to resolve, but the initiative to
fix and/or enhance things _must_ be on the side of the subtree
owners.  IOW, I won't be actively looking for bugs and rooms for
enhancements in them as the git maintainer -- I may only do so
just as one of the users when I want to scratch my own itch.  If
you have patches to things in contrib/ area, the patch should be
first sent to the primary author, and then the primary author
should ack and forward it to me (git pull request is nicer).
This is the same way as how I have been treating gitk, and to a
lesser degree various foreign SCM interfaces, so you know the
drill.

I expect that things that start their life in the contrib/ area
to graduate out of contrib/ once they mature, either by becoming
projects on their own, or moving to the toplevel directory.  On
the other hand, I expect I'll be proposing removal of disused
and inactive ones from time to time.

If you have new things to add to this area, please first propose
it on the git mailing list, and after a list discussion proves
there are some general interests (it does not have to be a
list-wide consensus for a tool targeted to a relatively narrow
audience -- for example I do not work with projects whose
upstream is svn, so I have no use for git-svn myself, but it is
of general interest for people who need to interoperate with SVN
repositories in a way git-svn works better than git-svnimport),
submit a patch to create a subdirectory of contrib/ and put your
stuff there.

-jc