From: Junio C Hamano <gitster@pobox•com>
To: Johannes Sixt <j.sixt@viscovery•net>
Cc: "SZEDER Gábor" <szeder@ira•uka.de>, git@vger•kernel.org
Subject: Re: [PATCH 12/19] bash prompt: use bash builtins to check whether inside git dir
Date: Wed, 09 May 2012 13:06:24 -0700 [thread overview]
Message-ID: <7vvck5qfun.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <4FAA25B9.3010208@viscovery.net> (Johannes Sixt's message of "Wed, 09 May 2012 10:07:21 +0200")
Johannes Sixt <j.sixt@viscovery•net> writes:
>> __git_ps1() runs the '$(git rev-parse --is-inside-git-dir)' command
>> substitution to check whether we are inside a .git directory and the
>> bash prompt needs to be adjusted accordingly (i.e. display 'BARE!' or
>> 'GIT_DIR!'). This imposes the overhead of fork()ing a subshell and
>> fork()+exec()ing a git process.
>>
>> Perform this check by comparing the path to the repository and the
>> current directory using only bash builtins, thereby sparing all that
>> fork()+exec() overhead.
>
>> - if [ "true" = "$(git rev-parse --is-inside-git-dir 2>/dev/null)" ]; then
>> + local pwd_p
>> + __git_pwd_p pwd_p
>> + # inside .git dir?
>> + if [ "$__git_dir" = "." -o \
>> + "${pwd_p#$__git_dir}" != "$pwd_p" ]; then
>
> At this point, $__git_dir is c:/dir style, whereas $pwd_p is /c/dir style,
> and the intended prefix check does not trigger.
>
> As long as $__git_dir is only used to access files, it does not matter
> whether it is Windows style or POSIX style. But if $__git_dir is used in a
> comparison, then you must make 100% sure that the involved paths are of
> the same vintage.
>
> What would be lost if this patch were dropped?
One loss of fork/exec is what would be lost, I would guess, and that seems
to be the primary point of this entire series, so...
At the conceptual level, I think the optimization in this patch makes
sense, but if the assumed primary beneficiary (i.e. Windows) cannot
benefit from this particular optimization due to two different path
representations, it wouldn't help being conceptually sound X-<.
next prev parent reply other threads:[~2012-05-09 20:06 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-09 0:44 [PATCH 00/19] Bash prompt speedup SZEDER Gábor
2012-05-09 0:44 ` [PATCH 01/19] tests: move code to run tests under bash into a helper library SZEDER Gábor
2012-05-09 0:44 ` [PATCH 02/19] tests: add tests for the bash prompt functions in the completion script SZEDER Gábor
2012-05-09 8:07 ` Johannes Sixt
2012-05-09 18:08 ` Junio C Hamano
2012-05-10 6:09 ` Johannes Sixt
2012-05-09 18:36 ` Junio C Hamano
2012-05-09 20:33 ` SZEDER Gábor
2012-05-09 0:44 ` [PATCH 03/19] completion: use __gitdir() in _git_log() SZEDER Gábor
2012-05-09 18:41 ` Junio C Hamano
2012-05-09 19:01 ` SZEDER Gábor
2012-05-09 0:44 ` [PATCH 04/19] completion: respect $GIT_DIR SZEDER Gábor
2012-05-09 8:09 ` Johannes Sixt
2012-05-09 18:54 ` Junio C Hamano
2012-05-09 0:44 ` [PATCH 05/19] bash prompt: don't show the prompt when .git/HEAD is unreadable SZEDER Gábor
2012-05-09 19:32 ` Junio C Hamano
2012-05-09 19:45 ` SZEDER Gábor
2012-05-09 0:44 ` [PATCH 06/19] bash prompt: return early from __git_ps1() when not in a git repository SZEDER Gábor
2012-05-09 0:44 ` [PATCH 07/19] completion: make __gitdir() store repository path in $__git_dir SZEDER Gábor
2012-05-09 19:36 ` Junio C Hamano
2012-05-09 0:44 ` [PATCH 08/19] completion: use $__git_dir instead of $(__gitdir) SZEDER Gábor
2012-05-09 19:43 ` Junio C Hamano
2012-05-09 20:22 ` SZEDER Gábor
2012-05-09 20:56 ` Junio C Hamano
2012-05-09 21:36 ` SZEDER Gábor
2012-05-09 0:44 ` [RFC PATCH 09/19] completion: platform-specific helper function to get physical path SZEDER Gábor
2012-05-09 7:37 ` Johannes Sixt
2012-05-09 0:44 ` [PATCH 10/19] completion: use bash builtins to search for repository SZEDER Gábor
2012-05-09 19:52 ` Junio C Hamano
2012-05-09 22:34 ` SZEDER Gábor
2012-05-09 22:59 ` Junio C Hamano
2012-05-09 0:44 ` [PATCH 11/19] bash prompt: use bash builtins to find out current branch SZEDER Gábor
2012-05-09 20:02 ` Junio C Hamano
2012-05-09 21:11 ` SZEDER Gábor
2012-05-09 21:25 ` Junio C Hamano
2012-05-09 21:45 ` SZEDER Gábor
2012-05-09 21:50 ` Junio C Hamano
2012-05-09 0:44 ` [PATCH 12/19] bash prompt: use bash builtins to check whether inside git dir SZEDER Gábor
2012-05-09 8:07 ` Johannes Sixt
2012-05-09 20:06 ` Junio C Hamano [this message]
2012-05-09 0:44 ` [PATCH 13/19] bash prompt: check whether inside the worktree only when necessary SZEDER Gábor
2012-05-09 0:44 ` [PATCH 14/19] bash prompt: use bash builtins to find out current branch during rebase SZEDER Gábor
2012-05-09 0:44 ` [PATCH 15/19] bash prompt: use bash builtins to get detached HEAD abbrev. object name SZEDER Gábor
2012-05-09 0:44 ` [PATCH 16/19] bash prompt: display stash and upstream state even inside the repository SZEDER Gábor
2012-05-09 0:44 ` [PATCH 17/19] bash prompt: use bash builtins to check stash state SZEDER Gábor
2012-05-09 0:44 ` [RFC PATCH 18/19] bash prompt: avoid command substitution when checking for untracked files SZEDER Gábor
2012-05-09 20:32 ` Junio C Hamano
2012-05-09 0:44 ` [PATCH 19/19] bash prompt: alternative git prompt without command substitution SZEDER Gábor
2012-05-09 19:38 ` Andrew Sayers
2012-05-09 22:08 ` SZEDER Gábor
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