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From: Jeff King <peff@peff.net>
To: Eric Sunshine <sunshine@sunshineco.com>
Cc: Duy Nguyen <pclouds@gmail.com>,
	Rafael Ascensao <rafa.almas@gmail.com>,
	Git Mailing List <git@vger.kernel.org>
Subject: Re: [PATCH 2/4] add chdir-notify API
Date: Wed, 28 Mar 2018 14:02:10 -0400	[thread overview]
Message-ID: <20180328180210.GA16565@sigill.intra.peff.net> (raw)
In-Reply-To: <CAPig+cQ0D+k+WmDWcaFHQj7DBb1RPfaUYwOvLosWXdHOzsoLOw@mail.gmail.com>

On Wed, Mar 28, 2018 at 01:58:18PM -0400, Eric Sunshine wrote:

> On Wed, Mar 28, 2018 at 1:40 PM, Jeff King <peff@peff.net> wrote:
> > [...]
> > Let's provide an API to let code that stores relative paths
> > "subscribe" to updates to the current working directory.
> > This means that callers of chdir() don't need to know about
> > all subscribers ahead of time; they can simply consult a
> > dynamically built list.
> > [...]
> > Signed-off-by: Jeff King <peff@peff.net>
> > ---
> > diff --git a/chdir-notify.c b/chdir-notify.c
> > @@ -0,0 +1,71 @@
> > +int chdir_notify(const char *new_cwd)
> > +{
> > +       struct strbuf old_cwd = STRBUF_INIT;
> > +       struct list_head *pos;
> > +
> > +       if (strbuf_getcwd(&old_cwd) < 0)
> > +               return -1;
> > +       if (chdir(new_cwd) < 0)
> > +               return -1;
> 
> This 'return' is leaking 'old_cwd', isn't it?

Whoops, yes. I wrote it the other way around first to avoid the leak,
but of course that has other problems. ;)

> > diff --git a/chdir-notify.h b/chdir-notify.h
> > @@ -0,0 +1,64 @@
> > + * In practice most callers will want to move a relative path to the new root;
> > + * they can use the reparent_relative_path() helper for that. If that's all
> > + * you're doing, you can also use the convenience function:
> > + *
> > + *   chdir_notify_reparent(&my_path);
> > + */
> > +typedef void (*chdir_notify_callback)(const char *old_cwd,
> > +                                     const char *new_cwd,
> > +                                     void *data);
> > +void chdir_notify_register(chdir_notify_callback cb, void *data);
> > +void chdir_notify_reparent(char **path);
> 
> Can we have some documentation here (or in the chdir_notify_reparent()
> example above) explaining that *path is a heap-allocated value? I had
> to consult the implementation to understand ownership.

Sure. I originally had reparent_relative_path() handle the freeing and
allocation, and it explained the ownership in its docstring. But as I
revised that to simply return its value, that got lost. I'll add it back
in here.

-Peff

  reply	other threads:[~2018-03-28 18:02 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-26 21:27 git complains packed-refs is not a directory when used with GIT_DIR and GIT_WORK_TREE envvars Rafael Ascensao
2018-03-26 21:44 ` Ævar Arnfjörð Bjarmason
2018-03-27  6:31 ` Jeff King
2018-03-27 14:56   ` Duy Nguyen
2018-03-27 16:47     ` Jeff King
2018-03-27 17:09       ` Duy Nguyen
2018-03-27 17:30         ` Duy Nguyen
2018-03-28  9:52           ` Jeff King
2018-03-28 10:10             ` Duy Nguyen
2018-03-28 17:36               ` Jeff King
2018-03-28 17:38                 ` [PATCH 1/4] set_git_dir: die when setenv() fails Jeff King
2018-03-28 17:40                 ` [PATCH 2/4] add chdir-notify API Jeff King
2018-03-28 17:58                   ` Eric Sunshine
2018-03-28 18:02                     ` Jeff King [this message]
2018-03-29 14:53                   ` Duy Nguyen
2018-03-29 17:48                     ` Jeff King
2018-03-29 18:12                       ` Duy Nguyen
2018-03-28 17:42                 ` [PATCH 3/4] set_work_tree: use chdir_notify Jeff King
2018-03-29 17:02                   ` Duy Nguyen
2018-03-29 17:23                     ` Duy Nguyen
2018-03-29 17:50                       ` Jeff King
2018-03-29 17:50                     ` Jeff King
2018-03-29 18:01                       ` Duy Nguyen
2018-03-30 17:23                         ` Jeff King
2018-03-28 17:43                 ` [PATCH 4/4] refs: use chdir_notify to update cached relative paths Jeff King
2018-03-30 18:34                 ` [PATCH v2 0/5] re-parenting relative directories after chdir Jeff King
2018-03-30 18:34                   ` [PATCH v2 1/5] set_git_dir: die when setenv() fails Jeff King
2018-03-30 18:34                   ` [PATCH v2 2/5] trace.c: export trace_setup_key Jeff King
2018-03-30 19:46                     ` Junio C Hamano
2018-03-30 19:47                       ` Jeff King
2018-03-30 19:50                         ` Junio C Hamano
2018-03-30 19:54                           ` Jeff King
2018-03-30 18:35                   ` [PATCH v2 3/5] add chdir-notify API Jeff King
2018-03-30 18:35                   ` [PATCH v2 4/5] set_work_tree: use chdir_notify Jeff King
2018-03-30 18:35                   ` [PATCH v2 5/5] refs: use chdir_notify to update cached relative paths Jeff King
2018-03-30 19:36                   ` [PATCH v2 0/5] re-parenting relative directories after chdir Duy Nguyen
2018-03-28  9:47         ` git complains packed-refs is not a directory when used with GIT_DIR and GIT_WORK_TREE envvars Jeff King
2018-03-28 17:55           ` [PATCH 0/8] " Nguyễn Thái Ngọc Duy
2018-03-28 17:55             ` [PATCH 1/8] strbuf.c: add strbuf_ensure_trailing_dr_sep() Nguyễn Thái Ngọc Duy
2018-03-28 17:55             ` [PATCH 2/8] strbuf.c: reintroduce get_pwd_cwd() (with strbuf_ prefix) Nguyễn Thái Ngọc Duy
2018-03-28 18:02               ` Stefan Beller
2018-03-28 18:05                 ` Duy Nguyen
2018-03-28 17:55             ` [PATCH 3/8] trace.c: export trace_setup_key Nguyễn Thái Ngọc Duy
2018-03-28 17:55             ` [PATCH 4/8] setup.c: introduce setup_adjust_path() Nguyễn Thái Ngọc Duy
2018-03-28 17:55             ` [PATCH 5/8] setup.c: allow other code to be notified when $CWD moves Nguyễn Thái Ngọc Duy
2018-03-28 17:55             ` [PATCH 6/8] environment.c: adjust env containing relpath when $CWD is moved Nguyễn Thái Ngọc Duy
2018-03-28 18:30               ` Jeff King
2018-03-28 18:45                 ` Duy Nguyen
2018-03-28 17:55             ` [PATCH 7/8] repository: adjust repo paths when $CWD moves Nguyễn Thái Ngọc Duy
2018-03-28 17:55             ` [PATCH 8/8] refs: adjust main " Nguyễn Thái Ngọc Duy
2018-03-28 18:19             ` [PATCH 0/8] Re: git complains packed-refs is not a directory when used with GIT_DIR and GIT_WORK_TREE envvars Jeff King
2018-03-29 14:57               ` Duy Nguyen
2018-03-30 17:21                 ` Jeff King
2018-03-28 22:24             ` Junio C Hamano

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