From: Junio C Hamano <gitster@pobox.com>
To: Lukas Fleischer <lfleischer@lfos.de>
Cc: git@vger.kernel.org, Nicolas Pitre <nico@fluxnic.net>,
Johannes Sixt <j6t@kdbg.org>
Subject: Re: [PATCH v2] Refactor recv_sideband()
Date: Tue, 14 Jun 2016 14:25:42 -0700 [thread overview]
Message-ID: <xmqqbn338nu1.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20160614210038.31465-1-lfleischer@lfos.de> (Lukas Fleischer's message of "Tue, 14 Jun 2016 23:00:38 +0200")
Lukas Fleischer <lfleischer@lfos.de> writes:
Lukas Fleischer <lfleischer@lfos.de> writes:
> Improve the readability of recv_sideband() significantly by replacing
s/significantly //; "making it readable" is already a subjective
goodness criterion, and you do not have to make it sound even more
subjective. Let the updated result convince the reader that it is
vastly more readable.
> Also, reorganize the overall control flow, remove some superfluous
> variables and replace a custom implementation of strpbrk() with a call
> to the standard C library function.
I find that calling the loop "a custom implementation" is a bit
unfair. The original tried to avoid looking beyond "len", but in
the updated code because you have buf[len] = '\0' to terminate the
line, and because you pass LARGE_PACKET_MAX to packet_read() while
your buf[] allocates one more byte, you can use strpbrk() here
safely. Which would mean "a custom implementation" was done for a
reason.
But that is a minor point.
I'll omit the preimage lines from the following.
> int recv_sideband(const char *me, int in_stream, int out)
> {
> + const char *term, *suffix;
> + char buf[LARGE_PACKET_MAX + 1];
> + struct strbuf outbuf = STRBUF_INIT;
> + const char *b, *brk;
>
> + strbuf_addf(&outbuf, "%s", PREFIX);
I highly suspect that you are better off without this line being
here.
> ...
> while (1) {
> int band, len;
> + len = packet_read(in_stream, NULL, NULL, buf, LARGE_PACKET_MAX, 0);
> if (len == 0)
> break;
> if (len < 1) {
> fprintf(stderr, "%s: protocol error: no band designator\n", me);
> return SIDEBAND_PROTOCOL_ERROR;
> }
> + band = buf[0] & 0xff;
> + buf[len] = '\0';
> len--;
> switch (band) {
> case 3:
> + fprintf(stderr, "%s%s\n", PREFIX, buf + 1);
> return SIDEBAND_REMOTE_ERROR;
Two "return"s we see above will leak outbuf.buf that holds PREFIX.
> case 2:
> + b = buf + 1;
>
> + /*
> + * Append a suffix to each nonempty line to clear the
> + * end of the screen line.
> + */
> + while ((brk = strpbrk(b, "\n\r"))) {
> + int linelen = brk - b;
>
> + if (linelen > 0) {
> + strbuf_addf(&outbuf, "%.*s%s%c",
> + linelen, b, suffix, *brk);
> } else {
> + strbuf_addf(&outbuf, "%c", *brk);
> }
> + xwrite(STDERR_FILENO, outbuf.buf, outbuf.len);
> + strbuf_reset(&outbuf);
> + strbuf_addf(&outbuf, "%s", PREFIX);
Instead of doing "we assume outbuf already has PREFIX when we add
contents from buf[]", the code structure would be better if you:
* make outbuf.buf contain PREFIX at the beginning of this innermost
loop; lose the reset/addf from here.
* move strbuf_reset(&outbuf) at the end of the next if (*b) block
to just before "continue;"
perhaps?
> + b = brk + 1;
> + }
>
> + if (*b) {
> + xwrite(STDERR_FILENO, outbuf.buf, outbuf.len);
> + /* Incomplete line, skip the next prefix. */
> + strbuf_reset(&outbuf);
> + }
> continue;
> case 1:
> + write_or_die(out, buf + 1, len);
> continue;
> default:
> fprintf(stderr, "%s: protocol error: bad band #%d\n",
next prev parent reply other threads:[~2016-06-14 21:25 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-13 19:52 [PATCH] Refactor recv_sideband() Lukas Fleischer
2016-06-13 21:07 ` Nicolas Pitre
2016-06-14 13:44 ` Johannes Schindelin
2016-06-14 15:04 ` Nicolas Pitre
2016-06-14 15:30 ` Johannes Schindelin
[not found] ` <Cq7rbYgOpb0CVCq7sbGmpL@videotron.ca>
2016-06-14 16:43 ` Nicolas Pitre
2016-06-14 17:09 ` Nicolas Pitre
[not found] ` <CsLdb3qLMBok7CsLebwX38@videotron.ca>
2016-06-14 17:55 ` Nicolas Pitre
2016-06-14 18:11 ` Junio C Hamano
2016-06-14 19:11 ` Lukas Fleischer
2016-06-14 19:16 ` Junio C Hamano
[not found] ` <Ct7VbfLfTHEALCt7Wbh8Xs@videotron.ca>
2016-06-14 20:10 ` Nicolas Pitre
2016-06-14 21:00 ` [PATCH v2] " Lukas Fleischer
2016-06-14 21:11 ` Lukas Fleischer
2016-06-14 21:25 ` Junio C Hamano [this message]
2016-06-15 3:44 ` Jeff King
[not found] ` <146597489449.32143.1327156804178869158@s-8d3a2dc3.on.site.uni-stuttgart.de>
2016-06-19 10:48 ` Lukas Fleischer
2016-06-24 15:31 ` Jeff King
2016-06-24 17:45 ` Johannes Schindelin
2016-06-24 18:14 ` Jeff King
2016-06-24 18:32 ` Junio C Hamano
2016-06-27 10:58 ` Lukas Fleischer
2016-06-27 15:54 ` Junio C Hamano
2016-06-27 16:16 ` Jeff King
2016-06-27 17:50 ` Junio C Hamano
2016-06-27 20:34 ` Lukas Fleischer
2016-06-27 20:47 ` Nicolas Pitre
2016-06-28 4:01 ` Lukas Fleischer
2016-06-28 5:20 ` Junio C Hamano
2016-06-28 10:04 ` Johannes Schindelin
2016-06-28 10:05 ` Johannes Schindelin
2016-06-28 15:13 ` Junio C Hamano
2016-06-28 16:21 ` Johannes Schindelin
2016-06-24 20:07 ` Dennis Kaarsemaker
2016-06-22 5:29 ` [PATCH v3] " Lukas Fleischer
2016-06-22 15:02 ` Nicolas Pitre
2016-06-22 22:47 ` Nicolas Pitre
2016-06-23 17:35 ` Lukas Fleischer
2016-06-23 18:59 ` Nicolas Pitre
2016-06-28 4:35 ` [PATCH v4] " Lukas Fleischer
2016-06-28 16:57 ` Junio C Hamano
2016-06-28 17:24 ` Junio C Hamano
2016-06-28 17:46 ` Nicolas Pitre
2016-06-28 18:13 ` Junio C Hamano
2016-06-28 18:28 ` Nicolas Pitre
2016-06-28 19:51 ` Junio C Hamano
2016-06-28 20:36 ` Nicolas Pitre
2016-06-28 21:09 ` Junio C Hamano
2016-06-28 21:44 ` Nicolas Pitre
2016-06-28 22:33 ` Junio C Hamano
2016-06-28 22:47 ` Junio C Hamano
2016-06-29 3:00 ` Junio C Hamano
2016-06-29 3:41 ` Nicolas Pitre
2016-06-29 2:02 ` Nicolas Pitre
2016-06-29 16:40 ` Junio C Hamano
2016-06-30 6:16 ` Lukas Fleischer
2016-07-01 20:01 ` Junio C Hamano
2016-07-05 20:35 ` Nicolas Pitre
2016-07-06 21:11 ` Junio C Hamano
2016-07-07 0:56 ` Nicolas Pitre
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