Xen devel - Feb 2013 - [PATCH v2] tools/xc: update tty detection in stdiostream_progress

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1361974429 -3600
# Node ID c438c98e13163cdb3106917469e3b86226f96168
# Parent  dc086ced6b0c7ecf21e56155f42fb16dabe39097
tools/xc: update tty detection in stdiostream_progress

As suggested by IanJ:
Check isatty only once to preserve the errno of ->progress users, and to
reduce the noice in strace output.

v2:
 - fix compile error
 - rename ->isatty to ->tty

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r dc086ced6b0c -r c438c98e1316 tools/libxc/xtl_logger_stdio.c
--- a/tools/libxc/xtl_logger_stdio.c
+++ b/tools/libxc/xtl_logger_stdio.c
@@ -35,6 +35,7 @@ struct xentoollog_logger_stdiostream {
     xentoollog_level min_level;
     unsigned flags;
     int progress_erase_len, progress_last_percent;
+    int tty;
 };
 
 static void progress_erase(xentoollog_logger_stdiostream *lg) {
@@ -118,7 +119,7 @@ static void stdiostream_progress(struct 
 
     lg->progress_last_percent = percent;
 
-    if (isatty(fileno(lg->f)) <= 0) {
+    if (!lg->tty) {
         stdiostream_message(logger_in, this_level, context,
                             "%s: %lu/%lu  %3d%%",
                             doing_what, done, total, percent);
@@ -166,6 +167,7 @@ xentoollog_logger_stdiostream *xtl_creat
     newlogger.f = f;
     newlogger.min_level = min_level;
     newlogger.flags = flags;
+    newlogger.tty = isatty(fileno(newlogger.f)) > 0;
 
     if (newlogger.flags & XTL_STDIOSTREAM_SHOW_DATE) tzset();

Olaf Hering writes ("[PATCH v2] tools/xc: update tty detection in
stdiostream_progress"):
> tools/xc: update tty detection in stdiostream_progress
> 
> As suggested by IanJ:
> Check isatty only once to preserve the errno of ->progress users, and to
> reduce the noice in strace output.
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

Thanks,
Ian.