2222from __future__ import division
2323from __future__ import print_function
2424
25+ import collections
2526import csv
2627import io
2728import string
@@ -76,6 +77,24 @@ def __call__(cls, *args, **kwargs):
7677 return type .__call__ (cls , * args )
7778
7879
80+ # NOTE about Genericity and Metaclass of ArgumentParser.
81+ # (1) In the .py source (this file)
82+ # - is not declared as Generic
83+ # - has _ArgumentParserCache as a metaclass
84+ # (2) In the .pyi source (type stub)
85+ # - is declared as Generic
86+ # - doesn't have a metaclass
87+ # The reason we need this is due to Generic having a different metaclass
88+ # (for python versions <= 3.7) and a class can have only one metaclass.
89+ #
90+ # * Lack of metaclass in .pyi is not a deal breaker, since the metaclass
91+ # doesn't affect any type information. Also type checkers can check the type
92+ # parameters.
93+ # * However, not declaring ArgumentParser as Generic in the source affects
94+ # runtime annotation processing. In particular this means, subclasses should
95+ # inherit from `ArgumentParser` and not `ArgumentParser[SomeType]`.
96+ # The corresponding DEFINE_someType method (the public API) can be annotated
97+ # to return FlagHolder[SomeType].
7998class ArgumentParser (six .with_metaclass (_ArgumentParserCache , object )):
8099 """Base class used to parse and convert arguments.
81100
@@ -354,11 +373,13 @@ def flag_type(self):
354373class EnumClassParser (ArgumentParser ):
355374 """Parser of an Enum class member."""
356375
357- def __init__ (self , enum_class ):
376+ def __init__ (self , enum_class , case_sensitive = True ):
358377 """Initializes EnumParser.
359378
360379 Args:
361380 enum_class: class, the Enum class with all possible flag values.
381+ case_sensitive: bool, whether or not the enum is to be case-sensitive. If
382+ False, all member names must be unique when case is ignored.
362383
363384 Raises:
364385 TypeError: When enum_class is not a subclass of Enum.
@@ -373,9 +394,30 @@ def __init__(self, enum_class):
373394 if not enum_class .__members__ :
374395 raise ValueError ('enum_class cannot be empty, but "{}" is empty.'
375396 .format (enum_class ))
397+ if not case_sensitive :
398+ members = collections .Counter (
399+ name .lower () for name in enum_class .__members__ )
400+ duplicate_keys = {
401+ member for member , count in members .items () if count > 1
402+ }
403+ if duplicate_keys :
404+ raise ValueError (
405+ 'Duplicate enum values for {} using case_sensitive=False' .format (
406+ duplicate_keys ))
376407
377408 super (EnumClassParser , self ).__init__ ()
378409 self .enum_class = enum_class
410+ self ._case_sensitive = case_sensitive
411+ if case_sensitive :
412+ self ._member_names = tuple (enum_class .__members__ )
413+ else :
414+ self ._member_names = tuple (
415+ name .lower () for name in enum_class .__members__ )
416+
417+ @property
418+ def member_names (self ):
419+ """The accepted enum names, in lowercase if not case sensitive."""
420+ return self ._member_names
379421
380422 def parse (self , argument ):
381423 """Determines validity of argument and returns the correct element of enum.
@@ -391,11 +433,19 @@ def parse(self, argument):
391433 """
392434 if isinstance (argument , self .enum_class ):
393435 return argument
394- if argument not in self .enum_class .__members__ :
395- raise ValueError ('value should be one of <%s>' %
396- '|' .join (self .enum_class .__members__ .keys ()))
436+ elif not isinstance (argument , six .string_types ):
437+ raise ValueError (
438+ '{} is not an enum member or a name of a member in {}' .format (
439+ argument , self .enum_class ))
440+ key = EnumParser (
441+ self ._member_names , case_sensitive = self ._case_sensitive ).parse (argument )
442+ if self ._case_sensitive :
443+ return self .enum_class [key ]
397444 else :
398- return self .enum_class [argument ]
445+ # If EnumParser.parse() return a value, we're guaranteed to find it
446+ # as a member of the class
447+ return next (value for name , value in self .enum_class .__members__ .items ()
448+ if name .lower () == key .lower ())
399449
400450 def flag_type (self ):
401451 """See base class."""
@@ -413,13 +463,30 @@ def serialize(self, value):
413463
414464
415465class EnumClassListSerializer (ListSerializer ):
466+ """A serializer for MultiEnumClass flags.
467+
468+ This serializer simply joins the output of `EnumClassSerializer` using a
469+ provided seperator.
470+ """
471+
472+ def __init__ (self , list_sep , ** kwargs ):
473+ """Initializes EnumClassListSerializer.
474+
475+ Args:
476+ list_sep: String to be used as a separator when serializing
477+ **kwargs: Keyword arguments to the `EnumClassSerializer` used to serialize
478+ individual values.
479+ """
480+ super (EnumClassListSerializer , self ).__init__ (list_sep )
481+ self ._element_serializer = EnumClassSerializer (** kwargs )
416482
417483 def serialize (self , value ):
418484 """See base class."""
419485 if isinstance (value , list ):
420- return self .list_sep .join (_helpers .str_or_unicode (x .name ) for x in value )
486+ return self .list_sep .join (
487+ self ._element_serializer .serialize (x ) for x in value )
421488 else :
422- return _helpers . str_or_unicode (value . name )
489+ return self . _element_serializer . serialize (value )
423490
424491
425492class CsvListSerializer (ArgumentSerializer ):
@@ -448,9 +515,18 @@ def serialize(self, value):
448515class EnumClassSerializer (ArgumentSerializer ):
449516 """Class for generating string representations of an enum class flag value."""
450517
518+ def __init__ (self , lowercase ):
519+ """Initializes EnumClassSerializer.
520+
521+ Args:
522+ lowercase: If True, enum member names are lowercased during serialization.
523+ """
524+ self ._lowercase = lowercase
525+
451526 def serialize (self , value ):
452527 """Returns a serialized string of the Enum class value."""
453- return _helpers .str_or_unicode (value .name )
528+ as_string = _helpers .str_or_unicode (value .name )
529+ return as_string .lower () if self ._lowercase else as_string
454530
455531
456532class BaseListParser (ArgumentParser ):
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