Resolve KASM-4489 "Feature/ watermark time"

unix/KasmVNC/CallbackValidator.pm

@@ -0,0 +1,37 @@
+package KasmVNC::CallbackValidator;
+
+use strict;
+use warnings;
+use v5.10;
+use Data::Dumper;
+
+use KasmVNC::Utils;
+
+sub new {
+    my ($class, $args) = @_;
+    my $self = bless {
+      isValidCallback => $args->{isValidCallback},
+      errorMessage => $args->{errorMessage}
+    }, $class;
+}
+
+sub validate {
+  my $self = shift;
+  $self->{configKey} = shift;
+  my @values = @{ listify($self->{configKey}->value()) };
+
+  foreach my $value (@values) {
+    $self->validateValue($value);
+  }
+}
+
+sub validateValue {
+  my $self = shift;
+  my $value = shift;
+
+  unless ($self->{isValidCallback}($value)) {
+    $self->{configKey}->addErrorMessage($self->{errorMessage});
+  }
+}
+
+1;

unix/KasmVNC/Utils.pm

@@ -45,6 +45,8 @@ sub isPresent {
 sub deriveBoolean {
   my $value = shift;
 
+  return $value if containsWideSymbols($value);
+
   switch($value) {
     case 'true' {
       return 1;
@@ -63,4 +65,12 @@ sub printStackTrace {
   print { *STDERR } $trace->as_string;
 }
 
+sub containsWideSymbols {
+	my $string = shift;
+
+  return 1 unless defined($string);
+
+	$string =~ /[^\x00-\xFF]/;
+}
+
 1;