git/contrib
Jeff King f932729cc7 memoize common git-path "constant" files
One of the most common uses of git_path() is to pass a
constant, like git_path("MERGE_MSG"). This has two
drawbacks:

  1. The return value is a static buffer, and the lifetime
     is dependent on other calls to git_path, etc.

  2. There's no compile-time checking of the pathname. This
     is OK for a one-off (after all, we have to spell it
     correctly at least once), but many of these constant
     strings appear throughout the code.

This patch introduces a series of functions to "memoize"
these strings, which are essentially globals for the
lifetime of the program. We compute the value once, take
ownership of the buffer, and return the cached value for
subsequent calls.  cache.h provides a helper macro for
defining these functions as one-liners, and defines a few
common ones for global use.

Using a macro is a little bit gross, but it does nicely
document the purpose of the functions. If we need to touch
them all later (e.g., because we learned how to change the
git_dir variable at runtime, and need to invalidate all of
the stored values), it will be much easier to have the
complete list.

Note that the shared-global functions have separate, manual
declarations. We could do something clever with the macros
(e.g., expand it to a declaration in some places, and a
declaration _and_ a definition in path.c). But there aren't
that many, and it's probably better to stay away from
too-magical macros.

Likewise, if we abandon the C preprocessor in favor of
generating these with a script, we could get much fancier.
E.g., normalizing "FOO/BAR-BAZ" into "git_path_foo_bar_baz".
But the small amount of saved typing is probably not worth
the resulting confusion to readers who want to grep for the
function's definition.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-10 15:37:14 -07:00
..
buildsystems mark Windows build scripts executable 2013-11-25 15:01:22 -08:00
completion Merge branch 'sg/bash-prompt-untracked-optim' 2015-08-03 11:01:26 -07:00
contacts contacts: add a Makefile to generate docs and install 2014-10-15 15:18:27 -07:00
convert-objects various contrib: Fix links in man pages 2014-08-07 09:43:21 -07:00
credential wincred: fix get credential if username has "@" 2015-01-25 20:08:56 -08:00
diff-highlight Merge branch 'jk/colors' into maint 2015-04-21 12:12:25 -07:00
emacs emacs: make 'git-status' work with separate git dirs 2012-11-26 09:34:28 -08:00
examples memoize common git-path "constant" files 2015-08-10 15:37:14 -07:00
fast-import comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
git-jump git-jump: ignore (custom) prefix in diff mode 2012-09-17 12:31:57 -07:00
git-shell-commands Add sample commands for git-shell 2010-08-12 15:16:31 -07:00
gitview various contrib: Fix links in man pages 2014-08-07 09:43:21 -07:00
hg-to-git hg-to-git: --allow-empty-message in git commit 2013-07-23 12:17:23 -07:00
hooks Merge branch 'pa/auto-gc-mac-osx' into maint 2015-07-15 11:41:17 -07:00
mw-to-git Merge branch 'ep/shell-command-substitution' 2014-06-03 12:06:45 -07:00
persistent-https Add persistent-https to contrib 2012-05-30 13:50:45 -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 Merge branch 'da/subtree-date-confusion' 2015-08-03 11:01:31 -07:00
svn-fe contrib/svn-fe: fix Makefile 2014-08-28 15:41:28 -07:00
thunderbird-patch-inline appp.sh: use the $( ... ) construct for command substitution 2014-04-23 15:17:01 -07:00
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 War on whitespace 2007-06-07 00:04:01 -07:00
remotes2config.sh contrib: Make remotes2config.sh script more robust 2007-12-04 14:35:08 -08:00
rerere-train.sh contrib/rerere-train: use installed git-sh-setup 2012-04-30 12:50:38 -07:00

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