On Tue, 28 Jun 2016, Junio C Hamano wrote:
> Junio C Hamano <gitster@xxxxxxxxx> writes:
>
> > It's just that if you take the latter, then the conditional after
> > the loop exits (i.e. the last transmission was an incomplete line)
> > cannot be "is outbuf empty?", as your base state is "has PREFIX and
> > can never be empty". I was working back from that if statement.
>
> Let's try this again. How does this look?
Still broken.
> In this version:
>
> - "outbuf" is where we keep the (possibly partial) data collected
> to be eventually shown;
>
> - output of pending (possibly partial) data is handled by a helper
> function drain(). It is responsible for prepending of the
> PREFIX, which is treated purely as a cosmetic thing. It also is
> responsible for completing an incomplete line at the end of the
> transmission (e.g. flushing of the buffered input upon reception of
> the emergency exit packet).
It uses strbuf_complete_line() which destroys the intended result for
lines that end with '\r'.
> - locally generated errors go directly to fprintf(stderr),
> bypassing outbuf (hence drain()).
>
> sideband.c | 43 +++++++++++++++++++++++++------------------
> 1 file changed, 25 insertions(+), 18 deletions(-)
>
> diff --git a/sideband.c b/sideband.c
> index 226a8c2..6873137 100644
> --- a/sideband.c
> +++ b/sideband.c
> @@ -18,6 +18,16 @@
> #define ANSI_SUFFIX "\033[K"
> #define DUMB_SUFFIX " "
>
> +static void drain(struct strbuf *outbuf)
> +{
> + if (!outbuf->len)
> + return;
> + strbuf_splice(outbuf, 0, 0, PREFIX, strlen(PREFIX));
> + strbuf_complete_line(outbuf);
> + fwrite(outbuf->buf, 1, outbuf->len, stderr);
> + strbuf_reset(outbuf);
> +}
> +
> int recv_sideband(const char *me, int in_stream, int out)
> {
> const char *term, *suffix;
> @@ -26,20 +36,21 @@ int recv_sideband(const char *me, int in_stream, int out)
> const char *b, *brk;
> int retval = 0;
>
> - strbuf_addf(&outbuf, "%s", PREFIX);
> term = getenv("TERM");
> if (isatty(2) && term && strcmp(term, "dumb"))
> suffix = ANSI_SUFFIX;
> else
> suffix = DUMB_SUFFIX;
>
> - while (retval == 0) {
> + while (!retval) {
> 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);
> + drain(&outbuf);
> + fprintf(stderr, "%s: protocol error: no band designator\n",
> + me);
> retval = SIDEBAND_PROTOCOL_ERROR;
> break;
> }
> @@ -48,7 +59,8 @@ int recv_sideband(const char *me, int in_stream, int out)
> len--;
> switch (band) {
> case 3:
> - fprintf(stderr, "%s%s\n", PREFIX, buf + 1);
> + drain(&outbuf);
> + strbuf_addf(&outbuf, "%s\n", buf + 1);
> retval = SIDEBAND_REMOTE_ERROR;
> break;
> case 2:
> @@ -58,13 +70,12 @@ 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 support 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;
> @@ -75,11 +86,7 @@ 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);
> - strbuf_reset(&outbuf);
> - strbuf_addf(&outbuf, "%s", PREFIX);
> -
> + drain(&outbuf);
> b = brk + 1;
> }
>
> @@ -90,6 +97,7 @@ int recv_sideband(const char *me, int in_stream, int out)
> write_or_die(out, buf + 1, len);
> break;
> default:
> + drain(&outbuf);
> fprintf(stderr, "%s: protocol error: bad band #%d\n",
> me, band);
> retval = SIDEBAND_PROTOCOL_ERROR;
> @@ -97,8 +105,7 @@ int recv_sideband(const char *me, int in_stream, int out)
> }
> }
>
> - if (outbuf.len > 0)
> - fprintf(stderr, "%.*s", (int)outbuf.len, outbuf.buf);
> + drain(&outbuf);
> strbuf_release(&outbuf);
> return retval;
> }
> --
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