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 <peff@peff.net> Helped-by: Junio C Hamano <gitster@pobox.com> Helped-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Lukas Fleischer <lfleischer@lfos.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Lukas Fleischer committed
Jun 28, 2016 at 06:35 UTC
5e5be9e257239b3599701f05518ce9e45f565e9f
1 file changed
+58
-74
sideband.c
+58
-74
@@ -13,111 +13,95 @@
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* the remote died unexpectedly. A flush() concludes the stream.
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*/
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-#define PREFIX "remote:"
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+#define PREFIX "remote: "
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#define ANSI_SUFFIX "\033[K"
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#define DUMB_SUFFIX " "
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-#define FIX_SIZE 10 /* large enough for any of the above */
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-
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int recv_sideband(const char *me, int in_stream, int out)
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{
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- unsigned pf = strlen(PREFIX);
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- unsigned sf;
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- char buf[LARGE_PACKET_MAX + 2*FIX_SIZE];
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- char *suffix, *term;
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- int skip_pf = 0;
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+ const char *term, *suffix;
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+ char buf[LARGE_PACKET_MAX + 1];
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+ struct strbuf outbuf = STRBUF_INIT;
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+ int retval = 0;
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- memcpy(buf, PREFIX, pf);
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term = getenv("TERM");
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if (isatty(2) && term && strcmp(term, "dumb"))
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suffix = ANSI_SUFFIX;
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else
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suffix = DUMB_SUFFIX;
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- sf = strlen(suffix);
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- while (1) {
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+ while (!retval) {
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+ const char *b, *brk;
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int band, len;
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- len = packet_read(in_stream, NULL, NULL, buf + pf, LARGE_PACKET_MAX, 0);
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+ len = packet_read(in_stream, NULL, NULL, buf, LARGE_PACKET_MAX, 0);
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if (len == 0)
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break;
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if (len < 1) {
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- fprintf(stderr, "%s: protocol error: no band designator\n", me);
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- return SIDEBAND_PROTOCOL_ERROR;
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+ strbuf_addf(&outbuf,
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+ "%s%s: protocol error: no band designator",
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+ outbuf.len ? "\n" : "", me);
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+ retval = SIDEBAND_PROTOCOL_ERROR;
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+ break;
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}
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- band = buf[pf] & 0xff;
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+ band = buf[0] & 0xff;
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+ buf[len] = '\0';
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len--;
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switch (band) {
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case 3:
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- buf[pf] = ' ';
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- buf[pf+1+len] = '\0';
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- fprintf(stderr, "%s\n", buf);
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- return SIDEBAND_REMOTE_ERROR;
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+ strbuf_addf(&outbuf, "%s%s%s", outbuf.len ? "\n" : "",
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+ PREFIX, buf + 1);
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+ retval = SIDEBAND_REMOTE_ERROR;
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+ break;
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case 2:
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- buf[pf] = ' ';
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- do {
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- char *b = buf;
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- int brk = 0;
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+ b = buf + 1;
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- /*
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- * If the last buffer didn't end with a line
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- * break then we should not print a prefix
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- * this time around.
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- */
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- if (skip_pf) {
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- b += pf+1;
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- } else {
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- len += pf+1;
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- brk += pf+1;
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- }
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-
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- /* Look for a line break. */
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- for (;;) {
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- brk++;
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- if (brk > len) {
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- brk = 0;
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- break;
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- }
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- if (b[brk-1] == '\n' ||
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- b[brk-1] == '\r')
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- break;
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- }
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+ /*
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+ * Append a suffix to each nonempty line to clear the
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+ * end of the screen line.
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+ *
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+ * The output is accumulated in a buffer and
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+ * each line is printed to stderr using
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+ * write(2) to ensure inter-process atomicity.
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+ */
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+ while ((brk = strpbrk(b, "\n\r"))) {
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+ int linelen = brk - b;
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- /*
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- * Let's insert a suffix to clear the end
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- * of the screen line if a line break was
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- * found. Also, if we don't skip the
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- * prefix, then a non-empty string must be
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- * present too.
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- */
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- if (brk > (skip_pf ? 0 : (pf+1 + 1))) {
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- char save[FIX_SIZE];
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- memcpy(save, b + brk, sf);
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- b[brk + sf - 1] = b[brk - 1];
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- memcpy(b + brk - 1, suffix, sf);
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- fprintf(stderr, "%.*s", brk + sf, b);
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- memcpy(b + brk, save, sf);
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- len -= brk;
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+ if (!outbuf.len)
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+ strbuf_addf(&outbuf, "%s", PREFIX);
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+ if (linelen > 0) {
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+ strbuf_addf(&outbuf, "%.*s%s%c",
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+ linelen, b, suffix, *brk);
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} else {
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- int l = brk ? brk : len;
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- fprintf(stderr, "%.*s", l, b);
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- len -= l;
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+ strbuf_addf(&outbuf, "%c", *brk);
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}
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+ xwrite(2, outbuf.buf, outbuf.len);
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+ strbuf_reset(&outbuf);
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- skip_pf = !brk;
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- memmove(buf + pf+1, b + brk, len);
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- } while (len);
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- continue;
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+ b = brk + 1;
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+ }
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+
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+ if (*b)
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+ strbuf_addf(&outbuf, "%s%s",
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+ outbuf.len ? "" : PREFIX, b);
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+ break;
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case 1:
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- write_or_die(out, buf + pf+1, len);
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- continue;
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+ write_or_die(out, buf + 1, len);
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+ break;
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default:
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- fprintf(stderr, "%s: protocol error: bad band #%d\n",
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- me, band);
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- return SIDEBAND_PROTOCOL_ERROR;
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+ strbuf_addf(&outbuf, "%s%s: protocol error: bad band #%d",
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+ outbuf.len ? "\n" : "", me, band);
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+ retval = SIDEBAND_PROTOCOL_ERROR;
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+ break;
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}
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}
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- return 0;
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+
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+ if (outbuf.len) {
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+ strbuf_addf(&outbuf, "\n");
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+ xwrite(2, outbuf.buf, outbuf.len);
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+ }
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+ strbuf_release(&outbuf);
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+ return retval;
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}
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/*