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From: Junio C Hamano <gitster@pobox.com>
To: Pierre Habouzit <madcoder@debian.org>
Cc: git@vger.kernel.org
Subject: Re: [PATCH] Simplify strbuf uses in archive-tar.c using the proper functions.
Date: Wed, 19 Sep 2007 01:06:24 -0700	[thread overview]
Message-ID: <7v8x73qdtr.fsf@gitster.siamese.dyndns.org> (raw)
In-Reply-To: <11890199232128-git-send-email-madcoder@debian.org> (Pierre Habouzit's message of "Wed, 5 Sep 2007 21:18:37 +0200")

Pierre Habouzit <madcoder@debian.org> writes:

>   This is just cleaner way to deal with strbufs, using its API rather than
> reinventing it in the module (e.g. strbuf_append_string is just the plain
> strbuf_addstr function, and it was used to perform what strbuf_addch does
> anyways).
> ---
>  archive-tar.c |   65 ++++++++++++++-------------------------------------------
>  1 files changed, 16 insertions(+), 49 deletions(-)
>
> diff --git a/archive-tar.c b/archive-tar.c
> index a0763c5..c84d7c0 100644
> --- a/archive-tar.c
> +++ b/archive-tar.c
> @@ -260,28 +237,18 @@ static int write_tar_entry(const unsigned char *sha1,
>                             const char *base, int baselen,
>                             const char *filename, unsigned mode, int stage)
>  {
> -	static struct strbuf path;
> +	static struct strbuf path = STRBUF_INIT;
>  	int filenamelen = strlen(filename);
>  	void *buffer;
>  	enum object_type type;
>  	unsigned long size;
>  
> -	if (!path.alloc) {
> -		path.buf = xmalloc(PATH_MAX);
> -		path.alloc = PATH_MAX;
> -		path.len = path.eof = 0;
> -	}
> -	if (path.alloc < baselen + filenamelen + 1) {
> -		free(path.buf);
> -		path.buf = xmalloc(baselen + filenamelen + 1);
> -		path.alloc = baselen + filenamelen + 1;
> -	}
> -	memcpy(path.buf, base, baselen);
> -	memcpy(path.buf + baselen, filename, filenamelen);
> -	path.len = baselen + filenamelen;
> -	path.buf[path.len] = '\0';
> +	strbuf_grow(&path, MAX(PATH_MAX, baselen + filenamelen + 1));

Where are you getting the MAX() macro from?  On my Linux box
it appears that <sys/params.h> happens to define it but I do not
think that is something we can rely upon portably.

Moreover, isn't this allocation wrong?  I thought "grow" was
about "we want this much more in addition to the existing
length", not "reserve at least this much", and this "path" is a
static that will keep the buffer and length from the previous
invocation.

> +	strbuf_reset(&path);
> +	strbuf_add(&path, base, baselen);
> +	strbuf_add(&path, filename, filenamelen);
>  	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
> -		strbuf_append_string(&path, "/");
> +		strbuf_addch(&path, '/');
>  		buffer = NULL;
>  		size = 0;
>  	} else {

Having said that, I suspect that the preallocation does not
really matter in practice.  How about doing something like:

	strbuf_reset(&path);
        strbuf_grow(&path, PATH_MAX);
        strbuf_add(&path, base, baselen);
        strbuf_add(&path, filename, filenamelen);

  parent reply	other threads:[~2007-09-19  8:06 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-09-02 22:42 strbuf API Pierre Habouzit
2007-09-03  5:43 ` Johan Herland
2007-09-03  8:46   ` Pierre Habouzit
2007-09-04  1:52     ` Miles Bader
2007-09-04  8:47       ` strbuf new semantics, let's give it a try Pierre Habouzit
2007-09-04  8:47       ` [PATCH] Rework strbuf API and semantics Pierre Habouzit
2007-09-04 11:11         ` Johannes Schindelin
2007-09-04 11:53           ` Pierre Habouzit
2007-09-04 13:34             ` Andreas Ericsson
2007-09-04 14:01             ` Pierre Habouzit
2007-09-04 15:44               ` Johannes Schindelin
2007-09-04 16:18                 ` Pierre Habouzit
2007-09-04 17:18                   ` Wincent Colaiuta
2007-09-04 14:01             ` [PATCH] Simplify strbuf uses in fast-import.c using the proper functions Pierre Habouzit
2007-09-04 23:46               ` René Scharfe
2007-09-04 23:46               ` René Scharfe
2007-09-05  7:48                 ` Pierre Habouzit
2007-09-05  8:05                   ` Junio C Hamano
2007-09-05  8:57                     ` Pierre Habouzit
2007-09-05 19:18                       ` [PATCH] Rework strbuf API and semantics Pierre Habouzit
2007-09-05 19:18                         ` [PATCH] Simplify strbuf uses in archive-tar.c using the proper functions Pierre Habouzit
2007-09-05 19:18                           ` [PATCH] Simplify strbuf uses in fast-import.c " Pierre Habouzit
2007-09-05 19:18                             ` [PATCH] Use proper strbuf API, and also simplify cmd_data code Pierre Habouzit
2007-09-05 19:18                               ` [PATCH] Simplify write_tree using strbuf's Pierre Habouzit
2007-09-05 19:18                                 ` [PATCH] Further strbuf re-engineering Pierre Habouzit
2007-09-05 19:18                                   ` [PATCH] Eradicate yet-another-buffer implementation in buitin-rerere.c Pierre Habouzit
2007-09-05 19:18                                     ` [PATCH] More strbuf uses in cache-tree.c Pierre Habouzit
2007-09-19  8:05                                   ` [PATCH] Further strbuf re-engineering Junio C Hamano
2007-09-05 19:21                             ` [PATCH] Simplify strbuf uses in fast-import.c using the proper functions Pierre Habouzit
2007-09-19  8:06                           ` Junio C Hamano [this message]
2007-09-19  8:36                             ` [PATCH] Simplify strbuf uses in archive-tar.c " Pierre Habouzit
2007-09-06  9:31                         ` [PATCH] Rework strbuf API and semantics Junio C Hamano
2007-09-06  9:49                           ` Pierre Habouzit
2007-09-06 10:03                         ` Junio C Hamano
2007-09-06 10:22                           ` Pierre Habouzit
2007-09-04 14:01             ` [PATCH] Use proper strbuf API, and also simplify cmd_data code Pierre Habouzit
2007-09-05  4:44             ` [PATCH] Rework strbuf API and semantics Miles Bader
2007-09-04  8:48       ` [PATCH] Add strbuf_fread, use it in fast-import.c Pierre Habouzit
2007-09-03  8:32 ` strbuf API Matthieu Moy
2007-09-03  8:49   ` Pierre Habouzit
2007-09-03  9:02     ` Matthieu Moy
2007-09-03  9:18     ` Junio C Hamano
2007-09-03 11:53       ` Pierre Habouzit
2007-09-03 12:29       ` Johannes Schindelin
2007-09-06 11:20 ` strbuf new API, take 2 for inclusion Pierre Habouzit
2007-09-06 11:20   ` [PATCH 1/7] Rework strbuf API and semantics Pierre Habouzit
2007-09-06 11:20     ` [PATCH 2/7] Simplify strbuf uses in archive-tar.c using the proper functions Pierre Habouzit
2007-09-06 11:20       ` [PATCH 3/7] Use proper strbuf API, and also simplify cmd_data code Pierre Habouzit
2007-09-06 11:20         ` [PATCH 4/7] Simplify write_tree using strbuf's Pierre Habouzit
2007-09-06 11:20           ` [PATCH 5/7] Further strbuf re-engineering Pierre Habouzit
2007-09-06 11:20             ` [PATCH 6/7] Eradicate yet-another-buffer implementation in buitin-rerere.c Pierre Habouzit
2007-09-06 11:20               ` [PATCH 7/7] More strbuf uses in cache-tree.c Pierre Habouzit
2007-09-06 14:05               ` [PATCH 6/7] Eradicate yet-another-buffer implementation in buitin-rerere.c Johannes Schindelin
2007-09-06 17:17                 ` Pierre Habouzit
2007-09-06 20:16                   ` David Kastrup
2007-09-06 20:54                     ` Pierre Habouzit
2007-09-07  8:03                   ` Junio C Hamano
2007-09-07  9:02                     ` Pierre Habouzit
2007-09-06 17:59       ` [PATCH 2/7] Simplify strbuf uses in archive-tar.c using the proper functions Kristian Høgsberg
2007-09-06 18:08         ` Pierre Habouzit
2007-09-06 18:18           ` Kristian Høgsberg
2007-09-06 18:27             ` Pierre Habouzit
2007-09-06 22:54               ` René Scharfe
2007-09-06 14:09     ` [PATCH 1/7] Rework strbuf API and semantics Johannes Schindelin
2007-09-06 14:21       ` Jeff King
2007-09-06 14:44         ` David Kastrup
2007-09-06 14:50           ` Jeff King
2007-09-06 15:06             ` David Kastrup
2007-09-06 15:36               ` Jeff King
2007-09-06 15:53                 ` David Kastrup
2007-09-06 15:45               ` Johannes Sixt
2007-09-06 14:43       ` David Kastrup
2007-09-06 14:52         ` Jeff King
2007-09-06 17:49     ` Kristian Høgsberg
2007-09-06 12:58   ` strbuf new API, take 2 for inclusion Jeff King
2007-09-06 17:15     ` Pierre Habouzit
2007-09-06 17:16       ` Jeff King
2007-09-06 17:19         ` Pierre Habouzit
2007-09-08 11:53 ` Use strbufs in commit.c (pretty printing) Pierre Habouzit
2007-09-08 11:53   ` [PATCH 1/3] Add strbuf_rtrim (to remove trailing spaces) Pierre Habouzit
2007-09-08 11:53     ` [PATCH 2/3] Change semantics of interpolate to work like snprintf Pierre Habouzit
2007-09-08 11:53       ` [PATCH 3/3] Rework pretty_print_commit to use strbufs instead of custom buffers Pierre Habouzit
2007-09-08 11:59         ` David Kastrup
2007-09-08 12:17           ` Pierre Habouzit
2007-09-08 12:28           ` Pierre Habouzit
2007-09-08 18:40         ` René Scharfe
2007-09-08 18:49           ` Pierre Habouzit
2007-09-08 16:18     ` [PATCH 1/3] Add strbuf_rtrim (to remove trailing spaces) René Scharfe
2007-09-08 22:53       ` Pierre Habouzit
2007-09-08 23:44         ` Pierre Habouzit

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