qemu-error: add {error, warn}_report_once_cond

Add two functions to print an error/warning report once depending
on a passed-in condition variable and flip it if printed. This is
useful if you want to print a message not once-globally, but e.g.
once-per-device.

Inspired by warn_once() in hw/vfio/ccw.c, which has been replaced
with warn_report_once_cond().

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20180830145902.27376-2-cohuck@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Function comments reworded]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This commit is contained in:
Cornelia Huck 2018-08-30 16:59:01 +02:00 committed by Markus Armbruster
parent d6f71af654
commit c55510b722
3 changed files with 48 additions and 15 deletions

View file

@ -310,3 +310,43 @@ void info_report(const char *fmt, ...)
vreport(REPORT_TYPE_INFO, fmt, ap);
va_end(ap);
}
/*
* Like error_report(), except print just once.
* If *printed is false, print the message, and flip *printed to true.
* Return whether the message was printed.
*/
bool error_report_once_cond(bool *printed, const char *fmt, ...)
{
va_list ap;
assert(printed);
if (*printed) {
return false;
}
*printed = true;
va_start(ap, fmt);
vreport(REPORT_TYPE_ERROR, fmt, ap);
va_end(ap);
return true;
}
/*
* Like warn_report(), except print just once.
* If *printed is false, print the message, and flip *printed to true.
* Return whether the message was printed.
*/
bool warn_report_once_cond(bool *printed, const char *fmt, ...)
{
va_list ap;
assert(printed);
if (*printed) {
return false;
}
*printed = true;
va_start(ap, fmt);
vreport(REPORT_TYPE_WARNING, fmt, ap);
va_end(ap);
return true;
}