Add basic validators

to be used by the properties and datatypes.
(more patches coming!)

Change-Id: I6adc8be2a3215e8f6ec2b4c28e16c5b509a28cbf
Reviewed-on: https://forge.frm2.tum.de/review/20406
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>

secop/basic_validators.py

@@ -0,0 +1,148 @@
+#  -*- coding: utf-8 -*-
+# *****************************************************************************
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# Module authors:
+#   Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
+#
+# *****************************************************************************
+"""basic validators (for properties)"""
+
+from __future__ import division, print_function
+
+import re
+
+from secop.errors import ProgrammingError
+
+try:
+    # py2
+    unicode
+except NameError:
+    # py3
+    unicode = str  # pylint: disable=redefined-builtin
+
+
+def FloatProperty(value):
+    return float(value)
+
+
+def PositiveFloatProperty(value):
+    value = float(value)
+    if value > 0:
+        return value
+    raise ValueError(u'Value must be >0 !')
+
+
+def NonNegativeFloatProperty(value):
+    value = float(value)
+    if value >= 0:
+        return value
+    raise ValueError(u'Value must be >=0 !')
+
+
+def IntProperty(value):
+    if int(value) == float(value):
+        return int(value)
+    raise ValueError(u'Can\'t convert %r to int!' % value)
+
+
+def PositiveIntProperty(value):
+    value = IntProperty(value)
+    if value > 0:
+        return value
+    raise ValueError(u'Value must be >0 !')
+
+
+def NonNegativeIntProperty(value):
+    value = IntProperty(value)
+    if value >= 0:
+        return value
+    raise ValueError(u'Value must be >=0 !')
+
+
+def BoolProperty(value):
+    try:
+        if value.lower() in [u'0', u'false', u'no', u'off',]:
+            return False
+        if value.lower() in [u'1', u'true', u'yes', u'on', ]:
+            return True
+    except AttributeError: # was no string
+        if bool(value) == value:
+            return value
+    raise ValueError(u'%r is no valid boolean: try one of True, False, "on", "off",...' % value)
+
+
+def StringProperty(value):
+    return unicode(value)
+
+
+def UnitProperty(value):
+    # probably too simple!
+    for s in unicode(value):
+        if s.lower() not in u'°abcdefghijklmnopqrstuvwxyz':
+            raise ValueError(u'%r is not a valid unit!')
+
+
+def FmtStrProperty(value, regexp=re.compile(r'^%\.?\d+[efg]$')):
+    value=unicode(value)
+    if regexp.match(value):
+        return value
+    raise ValueError(u'%r is not a valid fmtstr!' % value)
+
+
+def OneOfProperty(*args):
+    # literally oneof!
+    if not args:
+        raise ProgrammingError(u'OneOfProperty needs some argumets to check against!')
+    def OneOfChecker(value):
+        if value not in args:
+            raise ValueError(u'Value must be one of %r' % list(args))
+        return value
+    return OneOfChecker
+
+
+def NoneOr(checker):
+    if not callable(checker):
+        raise ProgrammingError(u'NoneOr needs a basic validator as Argument!')
+    def NoneOrChecker(value):
+        if value is None:
+            return None
+        return checker(value)
+    return NoneOrChecker
+
+
+def EnumProperty(**kwds):
+    if not kwds:
+        raise ProgrammingError(u'EnumProperty needs a mapping!')
+    def EnumChecker(value):
+        if value in kwds:
+            return kwds[value]
+        if value in kwds.values():
+            return value
+        raise ValueError(u'Value must be one of %r' % list(kwds))
+    return EnumChecker
+
+def TupleProperty(*checkers):
+    if not checkers:
+        checkers = [None]
+    for c in checkers:
+        if not callable(c):
+            raise ProgrammingError(u'TupleProperty needs basic validators as Arguments!')
+    def TupleChecker(values):
+        if len(values)==len(checkers):
+            return tuple(c(v) for c, v in zip(checkers, values))
+        raise ValueError(u'Value needs %d elements!' % len(checkers))
+    return TupleChecker