Before this patch, 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.
A strbuf is used for accumulating the output which is then printed using
a single fprintf() call with a single conversion specifier per line,
such that the atomicity of the output is preserved. See 9ac13ec (atomic
write for sideband remote messages, 2006-10-11) for details.
Helped-by: Jeff King <peff@xxxxxxxx>
Helped-by: Junio C Hamano <gitster@xxxxxxxxx>
Helped-by: Nicolas Pitre <nico@xxxxxxxxxxx>
Signed-off-by: Lukas Fleischer <lfleischer@xxxxxxx>
---
Changes since v3:
* The new code always frees the strbuf used for the output.
* Switched back to fprintf() to support ANSI codes under Windows.
* Added a comment on the tradeoff between atomicity and Windows support.
sideband.c | 125 ++++++++++++++++++++++++++-----------------------------------
1 file changed, 54 insertions(+), 71 deletions(-)
diff --git a/sideband.c b/sideband.c
index fde8adc..835d77d 100644
--- a/sideband.c
+++ b/sideband.c
@@ -13,111 +13,94 @@
* 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;
+ const char *b, *brk;
+ int retval = 0;
- memcpy(buf, PREFIX, pf);
+ strbuf_addf(&outbuf, "%s", PREFIX);
term = getenv("TERM");
if (isatty(2) && term && strcmp(term, "dumb"))
suffix = ANSI_SUFFIX;
else
suffix = DUMB_SUFFIX;
- sf = strlen(suffix);
- while (1) {
+ while (retval == 0) {
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;
+ 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;
+ fprintf(stderr, "%s%s\n", PREFIX, buf + 1);
+ retval = SIDEBAND_REMOTE_ERROR;
+ break;
case 2:
- buf[pf] = ' ';
- do {
- char *b = buf;
- int brk = 0;
-
- /*
- * 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;
- }
+ b = buf + 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 fprintf() with a single
+ * conversion specifier. This is a "best effort"
+ * approach to supporting both inter-process atomicity
+ * (single conversion specifiers are likely to end up
+ * in single atomic write() system calls) and the ANSI
+ * control code emulation under Windows.
+ */
+ 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 (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);
}
+ fprintf(stderr, "%.*s", (int)outbuf.len,
+ outbuf.buf);
+ strbuf_reset(&outbuf);
+ strbuf_addf(&outbuf, "%s", PREFIX);
+
+ b = brk + 1;
+ }
- skip_pf = !brk;
- memmove(buf + pf+1, b + brk, len);
- } while (len);
- continue;
+ if (*b)
+ strbuf_addf(&outbuf, "%s", 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;
+ retval = SIDEBAND_PROTOCOL_ERROR;
+ break;
}
}
- return 0;
+
+ if (outbuf.len > 0)
+ fprintf(stderr, "%.*s", (int)outbuf.len, outbuf.buf);
+ strbuf_release(&outbuf);
+ return retval;
}
/*
--
2.9.0
--
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