Re: [PATCH v5 1/8] pkt-line: add packet_read_line_gently()

[Lars Schneider <larsxschneider@gmail.com>]

> On 07 Apr 2017, at 14:03, Ben Peart <peartben@gmail.com> wrote:
> 
> Add packet_read_line_gently() to enable reading a line without dying on
> EOF.
> 
> Signed-off-by: Ben Peart <benpeart@microsoft.com>
> ---
> pkt-line.c | 12 ++++++++++++
> pkt-line.h | 10 ++++++++++
> 2 files changed, 22 insertions(+)
> 
> diff --git a/pkt-line.c b/pkt-line.c
> index d4b6bfe076..58842544b4 100644
> --- a/pkt-line.c
> +++ b/pkt-line.c
> @@ -323,6 +323,18 @@ char *packet_read_line(int fd, int *len_p)
> 	return packet_read_line_generic(fd, NULL, NULL, len_p);
> }
> 
> +int packet_read_line_gently(int fd, int *dst_len, char** dst_line)
> +{
> +	int len = packet_read(fd, NULL, NULL,
> +		packet_buffer, sizeof(packet_buffer),
> +		PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);

Really minor nit: you could align the parameters according to fd
similar to the "packet_read_line_generic" code (tab width 8).

> +	if (dst_len)
> +		*dst_len = len;
> +	if (dst_line)
> +		*dst_line = (len > 0) ? packet_buffer : NULL;

Minor nit: The explicit check "len > 0" is necessary here as len can
be "-1". The original "packet_read_line_generic" just checks for 
"len". I think it would be nice if the code would be consistent and both
would check "len > 0".

> +	return len;
> +}
> +
> char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
> {
> 	return packet_read_line_generic(-1, src, src_len, dst_len);
> diff --git a/pkt-line.h b/pkt-line.h
> index 18eac64830..12b18991f6 100644
> --- a/pkt-line.h
> +++ b/pkt-line.h
> @@ -74,6 +74,16 @@ int packet_read(int fd, char **src_buffer, size_t *src_len, char
> char *packet_read_line(int fd, int *size);
> 
> /*
> + * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF
> + * and CHOMP_NEWLINE options. The return value specifies the number of bytes
> + * read into the buffer or -1 on truncated input. if the *dst_line parameter

s/if/If/


> + * is not NULL it will return NULL for a flush packet and otherwise points to

This sentences is a bit confusing to me. Maybe:

If the *dst_line parameter is not NULL, then it will point to a static buffer
(that may be overwritten by subsequent calls) or it will return NULL for a flush 
packet.

... feel free to completely ignore this as I am no native speaker.

> + * a static buffer (that may be overwritten by subsequent calls). If the size
> + * parameter is not NULL, the length of the packet is written to it.
> + */
> +int packet_read_line_gently(int fd, int *size, char** dst_line);
> +
> +/*
>  * Same as packet_read_line, but read from a buf rather than a descriptor;
>  * see packet_read for details on how src_* is used.
>  */

If you send another round then you could address the minor nits.
If not, then this patch as it is looks good to me.

Thanks,
Lars