+=item check_options
+
+For a passed I<$options> hashref, validates any options that
+have 'validate' subroutines defined in the info hash,
+then validates the entire hashref if the price plan has
+its own 'validate' subroutine defined in the info hash
+(I<$options> values might be altered.)
+
+Returns error message, or empty string if valid.
+
+Invoked by L</insert> and L</replace> via the equivalent
+methods in L<FS::option_Common>.
+
+=cut
+
+sub check_options {
+ my ($self,$options) = @_;
+ foreach my $option (keys %$options) {
+ if (exists $plans{ $self->plan }->{fields}->{$option}) {
+ if (exists($plans{$self->plan}->{fields}->{$option}->{'validate'})) {
+ # pass option name for use in error message
+ # pass a reference to the $options value, so it can be cleaned up
+ my $error = &{$plans{$self->plan}->{fields}->{$option}->{'validate'}}($option,\($options->{$option}));
+ return $error if $error;
+ }
+ } # else "option does not exist" error?
+ }
+ if (exists($plans{$self->plan}->{'validate'})) {
+ my $error = &{$plans{$self->plan}->{'validate'}}($options);
+ return $error if $error;
+ }
+ return '';
+}
+