python: move Validator base class and ValidationError to getopt

It makes more sense for these to exist in the top package, because they are used by SambaOption.

validators.py can still exist in netcmd, just not the base class and exception.

Signed-off-by: Rob van der Linde <rob@catalyst.net.nz>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

python/samba/getopt.py

@@ -22,6 +22,7 @@ __docformat__ = "restructuredText"
 import optparse
 import os
 import sys
+from abc import ABCMeta, abstractmethod
 from copy import copy
 
 from samba.credentials import (
@@ -74,6 +75,17 @@ def check_bytes(option, opt, value):
         raise optparse.OptionValueError(msg)
 
 
+class ValidationError(Exception):
+    pass
+
+
+class Validator(metaclass=ABCMeta):
+
+    @abstractmethod
+    def __call__(self, field, value):
+        pass
+
+
 class SambaOption(optparse.Option):
     ATTRS = optparse.Option.ATTRS + ["validators"]
     TYPES = optparse.Option.TYPES + ("bytes",)