Re: [PATCH v2 3/7] prefer "!=" when checking read_in_full() result

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 27, 2017, 06:59 UTC
Message-ID: <xmqqr2us4ofw.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20170927060028.ehddn5zwf6v6jsvs@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 11 quoted lines

> diff --git a/csum-file.c b/csum-file.c
> index a172199e44..2adae04073 100644
> --- a/csum-file.c
> +++ b/csum-file.c
> @@ -19,7 +19,7 @@ static void flush(struct sha1file *f, const void *buf, unsigned int count)
>  
>  		if (ret < 0)
>  			die_errno("%s: sha1 file read error", f->name);
> -		if (ret < count)
> +		if (ret != count)
>  			die("%s: sha1 file truncated", f->name);

I personally find that this "ret < count" that comes after checking if ret is negative expresses what it is checking in a more natural way than "ret must be exactly count".

It is not a big deal, as either one needs to be read with an understanding that read_in_full() would read at most "count" bytes to see if the right condition is being checked to declare "truncated" anyway. But I somehow find

	ret = read up to count
	if (ret < 0)
		read failed
	if (ret < count)
		we failed to read as much as expected

a bit more natural.

Show 12 quoted lines

> diff --git a/pkt-line.c b/pkt-line.c
> index 647bbd3bce..93ea311443 100644
> --- a/pkt-line.c
> +++ b/pkt-line.c
> @@ -258,7 +258,7 @@ static int get_packet_data(int fd, char **src_buf, size_t *src_size,
>  	}
>  
>  	/* And complain if we didn't get enough bytes to satisfy the read. */
> -	if (ret < size) {
> +	if (ret != size) {
>  		if (options & PACKET_READ_GENTLE_ON_EOF)
>  			return -1;

Likewise, even though it is harder to see that this follows another explicit check for "ret < 0".

Thanks.