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Diffstat (limited to 'third_party/python_gflags/gflags_validators.py')
| -rwxr-xr-x | third_party/python_gflags/gflags_validators.py | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/third_party/python_gflags/gflags_validators.py b/third_party/python_gflags/gflags_validators.py new file mode 100755 index 0000000..d83058d5 --- /dev/null +++ b/third_party/python_gflags/gflags_validators.py @@ -0,0 +1,187 @@ +#!/usr/bin/env python + +# Copyright (c) 2010, Google Inc. +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# * Redistributions in binary form must reproduce the above +# copyright notice, this list of conditions and the following disclaimer +# in the documentation and/or other materials provided with the +# distribution. +# * Neither the name of Google Inc. nor the names of its +# contributors may be used to endorse or promote products derived from +# this software without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +"""Module to enforce different constraints on flags. + +A validator represents an invariant, enforced over a one or more flags. +See 'FLAGS VALIDATORS' in gflags.py's docstring for a usage manual. +""" + +__author__ = 'olexiy@google.com (Olexiy Oryeshko)' + + +class Error(Exception): + """Thrown If validator constraint is not satisfied.""" + + +class Validator(object): + """Base class for flags validators. + + Users should NOT overload these classes, and use gflags.Register... + methods instead. + """ + + # Used to assign each validator an unique insertion_index + validators_count = 0 + + def __init__(self, checker, message): + """Constructor to create all validators. + + Args: + checker: function to verify the constraint. + Input of this method varies, see SimpleValidator and + DictionaryValidator for a detailed description. + message: string, error message to be shown to the user + """ + self.checker = checker + self.message = message + Validator.validators_count += 1 + # Used to assert validators in the order they were registered (CL/18694236) + self.insertion_index = Validator.validators_count + + def Verify(self, flag_values): + """Verify that constraint is satisfied. + + flags library calls this method to verify Validator's constraint. + Args: + flag_values: gflags.FlagValues, containing all flags + Raises: + Error: if constraint is not satisfied. + """ + param = self._GetInputToCheckerFunction(flag_values) + if not self.checker(param): + raise Error(self.message) + + def GetFlagsNames(self): + """Return the names of the flags checked by this validator. + + Returns: + [string], names of the flags + """ + raise NotImplementedError('This method should be overloaded') + + def PrintFlagsWithValues(self, flag_values): + raise NotImplementedError('This method should be overloaded') + + def _GetInputToCheckerFunction(self, flag_values): + """Given flag values, construct the input to be given to checker. + + Args: + flag_values: gflags.FlagValues, containing all flags. + Returns: + Return type depends on the specific validator. + """ + raise NotImplementedError('This method should be overloaded') + + +class SimpleValidator(Validator): + """Validator behind RegisterValidator() method. + + Validates that a single flag passes its checker function. The checker function + takes the flag value and returns True (if value looks fine) or, if flag value + is not valid, either returns False or raises an Exception.""" + def __init__(self, flag_name, checker, message): + """Constructor. + + Args: + flag_name: string, name of the flag. + checker: function to verify the validator. + input - value of the corresponding flag (string, boolean, etc). + output - Boolean. Must return True if validator constraint is satisfied. + If constraint is not satisfied, it should either return False or + raise Error. + message: string, error message to be shown to the user if validator's + condition is not satisfied + """ + super(SimpleValidator, self).__init__(checker, message) + self.flag_name = flag_name + + def GetFlagsNames(self): + return [self.flag_name] + + def PrintFlagsWithValues(self, flag_values): + return 'flag --%s=%s' % (self.flag_name, flag_values[self.flag_name].value) + + def _GetInputToCheckerFunction(self, flag_values): + """Given flag values, construct the input to be given to checker. + + Args: + flag_values: gflags.FlagValues + Returns: + value of the corresponding flag. + """ + return flag_values[self.flag_name].value + + +class DictionaryValidator(Validator): + """Validator behind RegisterDictionaryValidator method. + + Validates that flag values pass their common checker function. The checker + function takes flag values and returns True (if values look fine) or, + if values are not valid, either returns False or raises an Exception. + """ + def __init__(self, flag_names, checker, message): + """Constructor. + + Args: + flag_names: [string], containing names of the flags used by checker. + checker: function to verify the validator. + input - dictionary, with keys() being flag_names, and value for each + key being the value of the corresponding flag (string, boolean, etc). + output - Boolean. Must return True if validator constraint is satisfied. + If constraint is not satisfied, it should either return False or + raise Error. + message: string, error message to be shown to the user if validator's + condition is not satisfied + """ + super(DictionaryValidator, self).__init__(checker, message) + self.flag_names = flag_names + + def _GetInputToCheckerFunction(self, flag_values): + """Given flag values, construct the input to be given to checker. + + Args: + flag_values: gflags.FlagValues + Returns: + dictionary, with keys() being self.lag_names, and value for each key + being the value of the corresponding flag (string, boolean, etc). + """ + return dict([key, flag_values[key].value] for key in self.flag_names) + + def PrintFlagsWithValues(self, flag_values): + prefix = 'flags ' + flags_with_values = [] + for key in self.flag_names: + flags_with_values.append('%s=%s' % (key, flag_values[key].value)) + return prefix + ', '.join(flags_with_values) + + def GetFlagsNames(self): + return self.flag_names |