Lukas Fleischer <lfleischer@xxxxxxx> writes:
> 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.
With input from Dscho that recent Git-for-Windows does the right
thing without limiting us to use only a subset of stdio, perhaps we
would want to squash something like this in.
diff --git a/sideband.c b/sideband.c
index 226a8c2..72e2c5c 100644
--- a/sideband.c
+++ b/sideband.c
@@ -58,13 +58,12 @@ int recv_sideband(const char *me, int in_stream, int out)
* 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.
+ * The output is accumulated in a buffer and
+ * each line is printed to stderr using
+ * fwrite(3). This is a "best effort"
+ * approach to suppor inter-process atomicity
+ * (single fwrite(3) call is likely to end up
+ * in single atomic write() system calls).
*/
while ((brk = strpbrk(b, "\n\r"))) {
int linelen = brk - b;
@@ -75,8 +74,7 @@ int recv_sideband(const char *me, int in_stream, int out)
} else {
strbuf_addf(&outbuf, "%c", *brk);
}
- fprintf(stderr, "%.*s", (int)outbuf.len,
- outbuf.buf);
+ fwrite(output.buf, 1, output.len, stderr);
strbuf_reset(&outbuf);
strbuf_addf(&outbuf, "%s", PREFIX);
@@ -98,7 +96,7 @@ int recv_sideband(const char *me, int in_stream, int out)
}
if (outbuf.len > 0)
- fprintf(stderr, "%.*s", (int)outbuf.len, outbuf.buf);
+ fwrite(output.buf, 1, output.len, stderr);
strbuf_release(&outbuf);
return retval;
}
--
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