From 5e5be9e257239b3599701f05518ce9e45f565e9f Mon Sep 17 00:00:00 2001 From: Lukas Fleischer Date: Tue, 28 Jun 2016 06:35:26 +0200 Subject: sideband.c: refactor recv_sideband() We used character buffer manipulations to split messages from the sideband at line breaks and insert "remote: " at the beginning of each line, using the packet size to determine the end of a message. However, since it is safe to assume that diagnostic messages from the sideband never contain NUL characters, we can also NUL-terminate the buffer, use strpbrk() for splitting lines and use format strings to insert the prefix, to make the code easier to read and maintain. A strbuf is used for accumulating the output which is then printed using a single write(2) call to ensure the atomicity of the output. See 9ac13ec (atomic write for sideband remote messages, 2006-10-11) for details. Helped-by: Jeff King Helped-by: Junio C Hamano Helped-by: Nicolas Pitre Signed-off-by: Lukas Fleischer Signed-off-by: Junio C Hamano --- sideband.c | 132 +++++++++++++++++++++++++++---------------------------------- 1 file changed, 58 insertions(+), 74 deletions(-) (limited to 'sideband.c') diff --git a/sideband.c b/sideband.c index 7f9dc229f..2782df800 100644 --- a/sideband.c +++ b/sideband.c @@ -13,111 +13,95 @@ * the remote died unexpectedly. A flush() concludes the stream. */ -#define PREFIX "remote:" +#define PREFIX "remote: " #define ANSI_SUFFIX "\033[K" #define DUMB_SUFFIX " " -#define FIX_SIZE 10 /* large enough for any of the above */ - int recv_sideband(const char *me, int in_stream, int out) { - unsigned pf = strlen(PREFIX); - unsigned sf; - char buf[LARGE_PACKET_MAX + 2*FIX_SIZE]; - char *suffix, *term; - int skip_pf = 0; + const char *term, *suffix; + char buf[LARGE_PACKET_MAX + 1]; + struct strbuf outbuf = STRBUF_INIT; + int retval = 0; - memcpy(buf, PREFIX, pf); term = getenv("TERM"); if (isatty(2) && term && strcmp(term, "dumb")) suffix = ANSI_SUFFIX; else suffix = DUMB_SUFFIX; - sf = strlen(suffix); - while (1) { + while (!retval) { + const char *b, *brk; int band, len; - len = packet_read(in_stream, NULL, NULL, buf + pf, LARGE_PACKET_MAX, 0); + 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; + strbuf_addf(&outbuf, + "%s%s: protocol error: no band designator", + outbuf.len ? "\n" : "", me); + retval = SIDEBAND_PROTOCOL_ERROR; + break; } - band = buf[pf] & 0xff; + band = buf[0] & 0xff; + buf[len] = '\0'; len--; switch (band) { case 3: - buf[pf] = ' '; - buf[pf+1+len] = '\0'; - fprintf(stderr, "%s\n", buf); - return SIDEBAND_REMOTE_ERROR; + strbuf_addf(&outbuf, "%s%s%s", outbuf.len ? "\n" : "", + PREFIX, buf + 1); + retval = SIDEBAND_REMOTE_ERROR; + break; case 2: - buf[pf] = ' '; - do { - char *b = buf; - int brk = 0; + b = buf + 1; - /* - * If the last buffer didn't end with a line - * break then we should not print a prefix - * this time around. - */ - if (skip_pf) { - b += pf+1; - } else { - len += pf+1; - brk += pf+1; - } - - /* Look for a line break. */ - for (;;) { - brk++; - if (brk > len) { - brk = 0; - break; - } - if (b[brk-1] == '\n' || - b[brk-1] == '\r') - break; - } + /* + * Append a suffix to each nonempty line to clear the + * end of the screen line. + * + * The output is accumulated in a buffer and + * each line is printed to stderr using + * write(2) to ensure inter-process atomicity. + */ + while ((brk = strpbrk(b, "\n\r"))) { + int linelen = brk - b; - /* - * Let's insert a suffix to clear the end - * of the screen line if a line break was - * found. Also, if we don't skip the - * prefix, then a non-empty string must be - * present too. - */ - if (brk > (skip_pf ? 0 : (pf+1 + 1))) { - char save[FIX_SIZE]; - memcpy(save, b + brk, sf); - b[brk + sf - 1] = b[brk - 1]; - memcpy(b + brk - 1, suffix, sf); - fprintf(stderr, "%.*s", brk + sf, b); - memcpy(b + brk, save, sf); - len -= brk; + if (!outbuf.len) + strbuf_addf(&outbuf, "%s", PREFIX); + if (linelen > 0) { + strbuf_addf(&outbuf, "%.*s%s%c", + linelen, b, suffix, *brk); } else { - int l = brk ? brk : len; - fprintf(stderr, "%.*s", l, b); - len -= l; + strbuf_addf(&outbuf, "%c", *brk); } + xwrite(2, outbuf.buf, outbuf.len); + strbuf_reset(&outbuf); - skip_pf = !brk; - memmove(buf + pf+1, b + brk, len); - } while (len); - continue; + b = brk + 1; + } + + if (*b) + strbuf_addf(&outbuf, "%s%s", + outbuf.len ? "" : PREFIX, b); + break; case 1: - write_or_die(out, buf + pf+1, len); - continue; + write_or_die(out, buf + 1, len); + break; default: - fprintf(stderr, "%s: protocol error: bad band #%d\n", - me, band); - return SIDEBAND_PROTOCOL_ERROR; + strbuf_addf(&outbuf, "%s%s: protocol error: bad band #%d", + outbuf.len ? "\n" : "", me, band); + retval = SIDEBAND_PROTOCOL_ERROR; + break; } } - return 0; + + if (outbuf.len) { + strbuf_addf(&outbuf, "\n"); + xwrite(2, outbuf.buf, outbuf.len); + } + strbuf_release(&outbuf); + return retval; } /* -- cgit v1.2.1 From c61b2af7bd2c7225bcf576a39c245cebf9397ead Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Tue, 5 Jul 2016 16:35:50 -0400 Subject: sideband.c: small optimization of strbuf usage Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano --- sideband.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'sideband.c') diff --git a/sideband.c b/sideband.c index 2782df800..c0b6dcf70 100644 --- a/sideband.c +++ b/sideband.c @@ -68,12 +68,12 @@ int recv_sideband(const char *me, int in_stream, int out) int linelen = brk - b; if (!outbuf.len) - strbuf_addf(&outbuf, "%s", PREFIX); + strbuf_addstr(&outbuf, PREFIX); if (linelen > 0) { strbuf_addf(&outbuf, "%.*s%s%c", linelen, b, suffix, *brk); } else { - strbuf_addf(&outbuf, "%c", *brk); + strbuf_addch(&outbuf, *brk); } xwrite(2, outbuf.buf, outbuf.len); strbuf_reset(&outbuf); @@ -97,7 +97,7 @@ int recv_sideband(const char *me, int in_stream, int out) } if (outbuf.len) { - strbuf_addf(&outbuf, "\n"); + strbuf_addch(&outbuf, '\n'); xwrite(2, outbuf.buf, outbuf.len); } strbuf_release(&outbuf); -- cgit v1.2.1