iframe-proxy | Sunbelt Computer Software

History

206 lines (173 loc) · 6.84 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

"""Helper to provide extensibility for pickle.

This is only useful to add pickle support for extension types defined in

C, not for instances of user-defined classes.

"""

__all__ = ["pickle", "constructor",

"add_extension", "remove_extension", "clear_extension_cache"]

dispatch_table = {}

def pickle(ob_type, pickle_function, constructor_ob=None):

if not callable(pickle_function):

raise TypeError("reduction functions must be callable")

dispatch_table[ob_type] = pickle_function

# The constructor_ob function is a vestige of safe for unpickling.

# There is no reason for the caller to pass it anymore.

if constructor_ob is not None:

constructor(constructor_ob)

def constructor(object):

if not callable(object):

raise TypeError("constructors must be callable")

# Example: provide pickling support for complex numbers.

try:

complex

except NameError:

pass

else:

def pickle_complex(c):

return complex, (c.real, c.imag)

pickle(complex, pickle_complex, complex)

# Support for pickling new-style objects

def _reconstructor(cls, base, state):

if base is object:

obj = object.__new__(cls)

else:

obj = base.__new__(cls, state)

if base.__init__ != object.__init__:

base.__init__(obj, state)

return obj

_HEAPTYPE = 1<<9

# Python code for object.__reduce_ex__ for protocols 0 and 1

def _reduce_ex(self, proto):

assert proto < 2

for base in self.__class__.__mro__:

if hasattr(base, '__flags__') and not base.__flags__ & _HEAPTYPE:

break

else:

base = object # not really reachable

if base is object:

state = None

else:

if base is self.__class__:

raise TypeError("can't pickle %s objects" % base.__name__)

state = base(self)

args = (self.__class__, base, state)

try:

getstate = self.__getstate__

except AttributeError:

if getattr(self, "__slots__", None):

raise TypeError("a class that defines __slots__ without "

"defining __getstate__ cannot be pickled")

try:

dict = self.__dict__

except AttributeError:

dict = None

else:

dict = getstate()

if dict:

return _reconstructor, args, dict

else:

return _reconstructor, args

# Helper for __reduce_ex__ protocol 2

def __newobj__(cls, *args):

return cls.__new__(cls, *args)

def __newobj_ex__(cls, args, kwargs):

"""Used by pickle protocol 4, instead of __newobj__ to allow classes with

keyword-only arguments to be pickled correctly.

"""

return cls.__new__(cls, *args, **kwargs)

def _slotnames(cls):

"""Return a list of slot names for a given class.

This needs to find slots defined by the class and its bases, so we

can't simply return the __slots__ attribute. We must walk down

the Method Resolution Order and concatenate the __slots__ of each

class found there. (This assumes classes don't modify their

__slots__ attribute to misrepresent their slots after the class is

defined.)

"""

# Get the value from a cache in the class if possible

names = cls.__dict__.get("__slotnames__")

if names is not None:

return names

# Not cached -- calculate the value

names = []

if not hasattr(cls, "__slots__"):

# This class has no slots

pass

else:

# Slots found -- gather slot names from all base classes

for c in cls.__mro__:

if "__slots__" in c.__dict__:

slots = c.__dict__['__slots__']

# if class has a single slot, it can be given as a string

if isinstance(slots, str):

slots = (slots,)

for name in slots:

# special descriptors

if name in ("__dict__", "__weakref__"):

continue

# mangled names

elif name.startswith('__') and not name.endswith('__'):

stripped = c.__name__.lstrip('_')

if stripped:

names.append('_%s%s' % (stripped, name))

else:

names.append(name)

else:

names.append(name)

# Cache the outcome in the class if at all possible

try:

cls.__slotnames__ = names

except:

pass # But don't die if we can't

return names

# A registry of extension codes. This is an ad-hoc compression

# mechanism. Whenever a global reference to <module>, <name> is about

# to be pickled, the (<module>, <name>) tuple is looked up here to see

# if it is a registered extension code for it. Extension codes are

# universal, so that the meaning of a pickle does not depend on

# context. (There are also some codes reserved for local use that

# don't have this restriction.) Codes are positive ints; 0 is

# reserved.

_extension_registry = {} # key -> code

_inverted_registry = {} # code -> key

_extension_cache = {} # code -> object

# Don't ever rebind those names: pickling grabs a reference to them when

# it's initialized, and won't see a rebinding.

def add_extension(module, name, code):

"""Register an extension code."""

code = int(code)

if not 1 <= code <= 0x7fffffff:

raise ValueError("code out of range")

key = (module, name)

if (_extension_registry.get(key) == code and

_inverted_registry.get(code) == key):

return # Redundant registrations are benign

if key in _extension_registry:

raise ValueError("key %s is already registered with code %s" %

(key, _extension_registry[key]))

if code in _inverted_registry:

raise ValueError("code %s is already in use for key %s" %

(code, _inverted_registry[code]))

_extension_registry[key] = code

_inverted_registry[code] = key

def remove_extension(module, name, code):

"""Unregister an extension code. For testing only."""

key = (module, name)

if (_extension_registry.get(key) != code or

_inverted_registry.get(code) != key):

raise ValueError("key %s is not registered with code %s" %

(key, code))

del _extension_registry[key]

del _inverted_registry[code]

if code in _extension_cache:

del _extension_cache[code]

def clear_extension_cache():

_extension_cache.clear()

# Standard extension code assignments

# Reserved ranges

# First Last Count Purpose

# 1 127 127 Reserved for Python standard library

# 128 191 64 Reserved for Zope

# 192 239 48 Reserved for 3rd parties

# 240 255 16 Reserved for private use (will never be assigned)

# 256 Inf Inf Reserved for future assignment

# Extension codes are assigned by the Python Software Foundation.

Sunbelt Computer Software

PL/B Language Development and Support

Navigation Menu

Uh oh!

Sunbelt Computer Software

PL/B Language Development and Support

Uh oh!

FilesExpand file tree

copyreg.py

Latest commit

History

copyreg.py

File metadata and controls