root / lib / outils.py @ 28d466dc
History | View | Annotate | Download (4.3 kB)
1 |
#
|
---|---|
2 |
#
|
3 |
|
4 |
# Copyright (C) 2012 Google Inc.
|
5 |
#
|
6 |
# This program is free software; you can redistribute it and/or modify
|
7 |
# it under the terms of the GNU General Public License as published by
|
8 |
# the Free Software Foundation; either version 2 of the License, or
|
9 |
# (at your option) any later version.
|
10 |
#
|
11 |
# This program is distributed in the hope that it will be useful, but
|
12 |
# WITHOUT ANY WARRANTY; without even the implied warranty of
|
13 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
14 |
# General Public License for more details.
|
15 |
#
|
16 |
# You should have received a copy of the GNU General Public License
|
17 |
# along with this program; if not, write to the Free Software
|
18 |
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
19 |
# 02110-1301, USA.
|
20 |
|
21 |
"""Module for object related utils."""
|
22 |
|
23 |
|
24 |
#: Supported container types for serialization/de-serialization (must be a
|
25 |
#: tuple as it's used as a parameter for C{isinstance})
|
26 |
_SEQUENCE_TYPES = (list, tuple, set, frozenset) |
27 |
|
28 |
|
29 |
class AutoSlots(type): |
30 |
"""Meta base class for __slots__ definitions.
|
31 |
|
32 |
"""
|
33 |
def __new__(mcs, name, bases, attrs): |
34 |
"""Called when a class should be created.
|
35 |
|
36 |
@param mcs: The meta class
|
37 |
@param name: Name of created class
|
38 |
@param bases: Base classes
|
39 |
@type attrs: dict
|
40 |
@param attrs: Class attributes
|
41 |
|
42 |
"""
|
43 |
assert "__slots__" not in attrs, \ |
44 |
"Class '%s' defines __slots__ when it should not" % name
|
45 |
|
46 |
attrs["__slots__"] = mcs._GetSlots(attrs)
|
47 |
|
48 |
return type.__new__(mcs, name, bases, attrs) |
49 |
|
50 |
@classmethod
|
51 |
def _GetSlots(mcs, attrs): |
52 |
"""Used to get the list of defined slots.
|
53 |
|
54 |
@param attrs: The attributes of the class
|
55 |
|
56 |
"""
|
57 |
raise NotImplementedError |
58 |
|
59 |
|
60 |
class ValidatedSlots(object): |
61 |
"""Sets and validates slots.
|
62 |
|
63 |
"""
|
64 |
__slots__ = [] |
65 |
|
66 |
def __init__(self, **kwargs): |
67 |
"""Constructor for BaseOpCode.
|
68 |
|
69 |
The constructor takes only keyword arguments and will set
|
70 |
attributes on this object based on the passed arguments. As such,
|
71 |
it means that you should not pass arguments which are not in the
|
72 |
__slots__ attribute for this class.
|
73 |
|
74 |
"""
|
75 |
slots = self.GetAllSlots()
|
76 |
for (key, value) in kwargs.items(): |
77 |
if key not in slots: |
78 |
raise TypeError("Object %s doesn't support the parameter '%s'" % |
79 |
(self.__class__.__name__, key))
|
80 |
setattr(self, key, value) |
81 |
|
82 |
@classmethod
|
83 |
def GetAllSlots(cls): |
84 |
"""Compute the list of all declared slots for a class.
|
85 |
|
86 |
"""
|
87 |
slots = [] |
88 |
for parent in cls.__mro__: |
89 |
slots.extend(getattr(parent, "__slots__", [])) |
90 |
return slots
|
91 |
|
92 |
def Validate(self): |
93 |
"""Validates the slots.
|
94 |
|
95 |
This method must be implemented by the child classes.
|
96 |
|
97 |
"""
|
98 |
raise NotImplementedError |
99 |
|
100 |
|
101 |
def ContainerToDicts(container): |
102 |
"""Convert the elements of a container to standard Python types.
|
103 |
|
104 |
This method converts a container with elements to standard Python types. If
|
105 |
the input container is of the type C{dict}, only its values are touched.
|
106 |
Those values, as well as all elements of input sequences, must support a
|
107 |
C{ToDict} method returning a serialized version.
|
108 |
|
109 |
@type container: dict or sequence (see L{_SEQUENCE_TYPES})
|
110 |
|
111 |
"""
|
112 |
if isinstance(container, dict): |
113 |
ret = dict([(k, v.ToDict()) for k, v in container.items()]) |
114 |
elif isinstance(container, _SEQUENCE_TYPES): |
115 |
ret = [elem.ToDict() for elem in container] |
116 |
else:
|
117 |
raise TypeError("Unknown container type '%s'" % type(container)) |
118 |
|
119 |
return ret
|
120 |
|
121 |
|
122 |
def ContainerFromDicts(source, c_type, e_type): |
123 |
"""Convert a container from standard python types.
|
124 |
|
125 |
This method converts a container with standard Python types to objects. If
|
126 |
the container is a dict, we don't touch the keys, only the values.
|
127 |
|
128 |
@type source: None, dict or sequence (see L{_SEQUENCE_TYPES})
|
129 |
@param source: Input data
|
130 |
@type c_type: type class
|
131 |
@param c_type: Desired type for returned container
|
132 |
@type e_type: element type class
|
133 |
@param e_type: Item type for elements in returned container (must have a
|
134 |
C{FromDict} class method)
|
135 |
|
136 |
"""
|
137 |
if not isinstance(c_type, type): |
138 |
raise TypeError("Container type '%s' is not a type" % type(c_type)) |
139 |
|
140 |
if source is None: |
141 |
source = c_type() |
142 |
|
143 |
if c_type is dict: |
144 |
ret = dict([(k, e_type.FromDict(v)) for k, v in source.items()]) |
145 |
elif c_type in _SEQUENCE_TYPES: |
146 |
ret = c_type(map(e_type.FromDict, source))
|
147 |
else:
|
148 |
raise TypeError("Unknown container type '%s'" % c_type) |
149 |
|
150 |
return ret
|