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1# Protocol Buffers - Google's data interchange format
2# Copyright 2008 Google Inc.  All rights reserved.
3# https://developers.google.com/protocol-buffers/
4#
5# Redistribution and use in source and binary forms, with or without
6# modification, are permitted provided that the following conditions are
7# met:
8#
9#     * Redistributions of source code must retain the above copyright
10# notice, this list of conditions and the following disclaimer.
11#     * Redistributions in binary form must reproduce the above
12# copyright notice, this list of conditions and the following disclaimer
13# in the documentation and/or other materials provided with the
14# distribution.
15#     * Neither the name of Google Inc. nor the names of its
16# contributors may be used to endorse or promote products derived from
17# this software without specific prior written permission.
18#
19# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31"""A simple wrapper around enum types to expose utility functions.
32
33Instances are created as properties with the same name as the enum they wrap
34on proto classes.  For usage, see:
35  reflection_test.py
36"""
37
38__author__ = 'rabsatt@google.com (Kevin Rabsatt)'
39
40import six
41
42
43class EnumTypeWrapper(object):
44  """A utility for finding the names of enum values."""
45
46  DESCRIPTOR = None
47
48  def __init__(self, enum_type):
49    """Inits EnumTypeWrapper with an EnumDescriptor."""
50    self._enum_type = enum_type
51    self.DESCRIPTOR = enum_type  # pylint: disable=invalid-name
52
53  def Name(self, number):  # pylint: disable=invalid-name
54    """Returns a string containing the name of an enum value."""
55    try:
56      return self._enum_type.values_by_number[number].name
57    except KeyError:
58      pass  # fall out to break exception chaining
59
60    if not isinstance(number, six.integer_types):
61      raise TypeError(
62          'Enum value for {} must be an int, but got {} {!r}.'.format(
63              self._enum_type.name, type(number), number))
64    else:
65      # repr here to handle the odd case when you pass in a boolean.
66      raise ValueError('Enum {} has no name defined for value {!r}'.format(
67          self._enum_type.name, number))
68
69  def Value(self, name):  # pylint: disable=invalid-name
70    """Returns the value corresponding to the given enum name."""
71    try:
72      return self._enum_type.values_by_name[name].number
73    except KeyError:
74      pass  # fall out to break exception chaining
75    raise ValueError('Enum {} has no value defined for name {!r}'.format(
76        self._enum_type.name, name))
77
78  def keys(self):
79    """Return a list of the string names in the enum.
80
81    Returns:
82      A list of strs, in the order they were defined in the .proto file.
83    """
84
85    return [value_descriptor.name
86            for value_descriptor in self._enum_type.values]
87
88  def values(self):
89    """Return a list of the integer values in the enum.
90
91    Returns:
92      A list of ints, in the order they were defined in the .proto file.
93    """
94
95    return [value_descriptor.number
96            for value_descriptor in self._enum_type.values]
97
98  def items(self):
99    """Return a list of the (name, value) pairs of the enum.
100
101    Returns:
102      A list of (str, int) pairs, in the order they were defined
103      in the .proto file.
104    """
105    return [(value_descriptor.name, value_descriptor.number)
106            for value_descriptor in self._enum_type.values]
107
108  def __getattr__(self, name):
109    """Returns the value corresponding to the given enum name."""
110    try:
111      return self._enum_type.values_by_name[name].number
112    except KeyError:
113      pass  # fall out to break exception chaining
114    raise AttributeError('Enum {} has no value defined for name {!r}'.format(
115        self._enum_type.name, name))
116