On Fri, Mar 27, 2015 at 11:01:23AM +0100, Pavel Hrdina wrote:
> Similar to VIR_EXLUSIVE_FLAGS, it will error out if flag requirement is
> not met.
>
> Signed-off-by: Pavel Hrdina <phrdina@xxxxxxxxxx>
> ---
> src/internal.h | 43 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/src/internal.h b/src/internal.h
> index eb8d231..6363e58 100644
> --- a/src/internal.h
> +++ b/src/internal.h
> @@ -371,6 +371,49 @@
> goto LABEL; \
> }
>
> +/* Macros to help dealing with flag requirements. */
> +
> +/**
> + * VIR_REQUIRE_FLAG_RET:
> + *
> + * @FLAG1: First flag to be checked.
> + * @FLAG2: Second flag that is required by first flag.
> + * @RET: Return value.
> + *
> + * Check whether required flag is set. The checked flags are compared
> + * with flags variable.
> + *
> + * This helper does an early return and therefore it has to be called
> + * before anything that would require cleanup.
> + */
> +# define VIR_REQUIRE_FLAG_RET(FLAG1, FLAG2, RET) \
> + if ((flags & FLAG1) && !(flags & FLAG2)) { \
> + virReportInvalidArg(ctl, \
> + _("Flag '%s' is required by flag '%s'"), \
> + #FLAG2, #FLAG1); \
> + return RET; \
> + }
> +
I recommend encapsulating this within a "do { ... } while (1)"
statement. The problem is that the macro hides/exposes an -if-
statement to which an -else- keyword can be bound:
if (something)
VIR_REQUIRE_FLAG_RET(f1, f2, foo)
else // matches with -if- inside VIR_REQUIRE_FLAG_RET
// doesn't execute when you think it does
Note that other macros (see definition of virCheckNonNullArgReturn
below) follow this practice.
> +/**
> + * VIR_REQUIRE_FLAG_GOTO:
> + *
> + * @FLAG1: First flag to be checked.
> + * @FLAG2: Second flag that is required by first flag.
> + * @LABEL: Label to jump to.
> + *
> + * Check whether required flag is set. The checked flags are compared
> + * with flags variable.
> + *
> + * Returns nothing. Jumps to a label if required flag is not set.
> + */
> +# define VIR_REQUIRE_FLAG_GOTO(FLAG1, FLAG2, LABEL) \
> + if ((flags & FLAG1) && !(flags & FLAG2)) { \
> + virReportInvalidArg(ctl, \
> + _("Flag '%s' is required by flag '%s'"), \
> + #FLAG2, #FLAG1); \
> + goto LABEL; \
> + }
> +
Same feedback as above.
-Jeff
> # define virCheckNonNullArgReturn(argname, retval) \
> do { \
> if (argname == NULL) { \
> --
> 2.0.5
>
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