Cornelia Huck <coh...@redhat.com> writes:
> 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 <coh...@redhat.com>
> ---
> hw/vfio/ccw.c | 18 +++--------------
> include/qemu/error-report.h | 5 +++++
> util/qemu-error.c | 48
> +++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 56 insertions(+), 15 deletions(-)
>
> diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
> index e96bbdc78b..9246729a75 100644
> --- a/hw/vfio/ccw.c
> +++ b/hw/vfio/ccw.c
> @@ -37,24 +37,12 @@ typedef struct VFIOCCWDevice {
> bool warned_orb_pfch;
> } VFIOCCWDevice;
>
> -static inline void warn_once(bool *warned, const char *fmt, ...)
> -{
> - va_list ap;
> -
> - if (!warned || *warned) {
> - return;
> - }
> - *warned = true;
> - va_start(ap, fmt);
> - warn_vreport(fmt, ap);
> - va_end(ap);
> -}
> -
> static inline void warn_once_pfch(VFIOCCWDevice *vcdev, SubchDev *sch,
> const char *msg)
> {
> - warn_once(&vcdev->warned_orb_pfch, "vfio-ccw (devno %x.%x.%04x): %s",
> - sch->cssid, sch->ssid, sch->devno, msg);
> + warn_report_once_cond(&vcdev->warned_orb_pfch,
> + "vfio-ccw (devno %x.%x.%04x): %s",
> + sch->cssid, sch->ssid, sch->devno, msg);
> }
>
> static void vfio_ccw_compute_needs_reset(VFIODevice *vdev)
> diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
> index 72fab2b031..e415128ac4 100644
> --- a/include/qemu/error-report.h
> +++ b/include/qemu/error-report.h
> @@ -44,6 +44,11 @@ void error_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
> void warn_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
> void info_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
>
> +bool error_report_once_cond(bool *printed, const char *fmt, ...)
> + GCC_FMT_ATTR(2, 3);
> +bool warn_report_once_cond(bool *printed, const char *fmt, ...)
> + GCC_FMT_ATTR(2, 3);
> +
> /*
> * Similar to error_report(), except it prints the message just once.
> * Return true when it prints, false otherwise.
> diff --git a/util/qemu-error.c b/util/qemu-error.c
> index a25d3b94c6..b77e0bac4c 100644
> --- a/util/qemu-error.c
> +++ b/util/qemu-error.c
> @@ -310,3 +310,51 @@ void info_report(const char *fmt, ...)
> vreport(REPORT_TYPE_INFO, fmt, ap);
> va_end(ap);
> }
> +
> +/*
> + * If *printed is false, print an error message to current monitor if we
> + * have one, else to stderr, and flip *printed to true.
I like function contracts to state the function's purpose in one line if
at all possible. Perhaps:
* Like error_report(), except print just once.
* If *printed is false, print the message, and flip *printed to true.
> + * Returns false if message was not printed, else true.
Uh, confusing negative. What about
* Return whether the message was printed.
Happy to make these tweaks in my tree.
> + * Format arguments like sprintf(). The resulting message should be
> + * a single phrase, with no newline or trailing punctuation.
> + * Prepend the current location and append a newline.
> + * It's wrong to call this in a QMP monitor. Use error_setg() there.
> + */
> +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;
> +}
> +
> +/*
> + * If *printed is false, print a warning message to current monitor if we
> + * have one, else to stderr, and flip *printed to true.
> + * Returns false if message was not printed, else true.
> + * Format arguments like sprintf(). The resulting message should be
> + * a single phrase, with no newline or trailing punctuation.
> + * Prepend the current location and append a newline.
> + * It's wrong to call this in a QMP monitor. Use error_setg() there.
> + */
> +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;
> +}
Preferably with improved comments:
Reviewed-by: Markus Armbruster <arm...@redhat.com>
