Re: [PATCH] GSoC2014 Microproject rewrite finish_bulk_checkin()

[Michael Haggerty <mhagger@alum.mit.edu>]

On 02/27/2014 08:02 PM, Faiz Kothari wrote:
> Signed-off-by: Faiz Kothari <faiz.off93@gmail.com>
> ---
>  bulk-checkin.c |   12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/bulk-checkin.c b/bulk-checkin.c
> index 118c625..feeff9f 100644
> --- a/bulk-checkin.c
> +++ b/bulk-checkin.c
> @@ -23,7 +23,7 @@ static struct bulk_checkin_state {
>  static void finish_bulk_checkin(struct bulk_checkin_state *state)
>  {
>  	unsigned char sha1[20];
> -	char packname[PATH_MAX];
> +	struct strbuf packname;
>  	int i;
>  
>  	if (!state->f)
> @@ -42,9 +42,11 @@ static void finish_bulk_checkin(struct bulk_checkin_state *state)
>  					 state->offset);
>  		close(fd);
>  	}
> -
> -	sprintf(packname, "%s/pack/pack-", get_object_directory());
> -	finish_tmp_packfile(packname, state->pack_tmp_name,
> +	
> +	packname.len = packname.alloc = 64 + strlen(get_object_directory());
> +	packname.buf = (char *)malloc(packname.len * sizeof(char));
> +	sprintf(packname.buf, "%s/pack/pack-", get_object_directory());
> +	finish_tmp_packfile(packname.buf, state->pack_tmp_name,
>  			    state->written, state->nr_written,
>  			    &state->pack_idx_opts, sha1);
>  	for (i = 0; i < state->nr_written; i++)
> @@ -53,7 +55,7 @@ static void finish_bulk_checkin(struct bulk_checkin_state *state)
>  clear_exit:
>  	free(state->written);
>  	memset(state, 0, sizeof(*state));
> -
> +	free(packname.buf);
>  	/* Make objects we just wrote available to ourselves */
>  	reprepare_packed_git();
>  }
> -- 1.7.9.5
>> Rewrite bulk-checkin.c:finish_bulk_checkin() to use a strbuf for handling packname, and explain why this is useful.
>> Also check if the first argument of pack-write.c:finish_tmp_packfile() can be made const.
> 
> Adding 64 to strlen(get_object_directory()) to accomodate sha1_to_hex(sha1) and itself.
> Using the APIs for strbuf is giving me test failures(12/15) during t1050-large.sh 
> So, I used the malloc() and free() instead.

This is not OK.  I promise you, the strbuf API works correctly if it is
used correctly.  (And if it really *were* broken, you should fix the
problem or at least diagnose and document it rather than working around it.)

> Instead of having packname on stack and cause stackoverflow because of MAX_PATH ~ 4KB, have it on heap.
> Can have first parameter to pack-write.c:finish_tmp_packfile() as const because packname is not required to be modified.
> 
> I apologise for my two earlier patches not being in proper format. I have finally got it working properly. Will make sure,
> it does not happen again.

Almost.  This last set of comments should be moved to directly after the
"---" line.

But: please rather stick to *one* microproject and get it perfect, and
leave the others to other students.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/