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cpython/Lib/pickle.py
Tim Peters d97da80dd5 save_tuple(): So long as the charter is rewriting for clarity, the snaky 
control flow had to be simplified.
2003-01-28 05:48:29 +00:00

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"""Create portable serialized representations of Python objects.
See module cPickle for a (much) faster implementation.
See module copy_reg for a mechanism for registering custom picklers.
See module pickletools source for extensive comments.
Classes:
Pickler
Unpickler
Functions:
dump(object, file)
dumps(object) -> string
load(file) -> object
loads(string) -> object
Misc variables:
__version__
format_version
compatible_formats
"""
__version__ = "$Revision$" # Code version
from types import *
from copy_reg import dispatch_table, safe_constructors
import marshal
import sys
import struct
import re
__all__ = ["PickleError", "PicklingError", "UnpicklingError", "Pickler",
"Unpickler", "dump", "dumps", "load", "loads"]
# These are purely informational; no code usues these
format_version = "2.0" # File format version we write
compatible_formats = ["1.0", # Original protocol 0
"1.1", # Protocol 0 with class supprt added
"1.2", # Original protocol 1
"1.3", # Protocol 1 with BINFLOAT added
"2.0", # Protocol 2
] # Old format versions we can read
# Why use struct.pack() for pickling but marshal.loads() for
# unpickling? struct.pack() is 40% faster than marshal.loads(), but
# marshal.loads() is twice as fast as struct.unpack()!
mloads = marshal.loads
class PickleError(Exception):
"""A common base class for the other pickling exceptions."""
pass
class PicklingError(PickleError):
"""This exception is raised when an unpicklable object is passed to the
dump() method.
"""
pass
class UnpicklingError(PickleError):
"""This exception is raised when there is a problem unpickling an object,
such as a security violation.
Note that other exceptions may also be raised during unpickling, including
(but not necessarily limited to) AttributeError, EOFError, ImportError,
and IndexError.
"""
pass
class _Stop(Exception):
def __init__(self, value):
self.value = value
try:
from org.python.core import PyStringMap
except ImportError:
PyStringMap = None
try:
UnicodeType
except NameError:
UnicodeType = None
# Pickle opcodes. See pickletools.py for extensive docs. The listing
# here is in kind-of alphabetical order of 1-character pickle code.
# pickletools groups them by purpose.
MARK = '(' # push special markobject on stack
STOP = '.' # every pickle ends with STOP
POP = '0' # discard topmost stack item
POP_MARK = '1' # discard stack top through topmost markobject
DUP = '2' # duplicate top stack item
FLOAT = 'F' # push float object; decimal string argument
INT = 'I' # push integer or bool; decimal string argument
BININT = 'J' # push four-byte signed int
BININT1 = 'K' # push 1-byte unsigned int
LONG = 'L' # push long; decimal string argument
BININT2 = 'M' # push 2-byte unsigned int
NONE = 'N' # push None
PERSID = 'P' # push persistent object; id is taken from string arg
BINPERSID = 'Q' # " " " ; " " " " stack
REDUCE = 'R' # apply callable to argtuple, both on stack
STRING = 'S' # push string; NL-terminated string argument
BINSTRING = 'T' # push string; counted binary string argument
SHORT_BINSTRING = 'U' # " " ; " " " " < 256 bytes
UNICODE = 'V' # push Unicode string; raw-unicode-escaped'd argument
BINUNICODE = 'X' # " " " ; counted UTF-8 string argument
APPEND = 'a' # append stack top to list below it
BUILD = 'b' # call __setstate__ or __dict__.update()
GLOBAL = 'c' # push self.find_class(modname, name); 2 string args
DICT = 'd' # build a dict from stack items
EMPTY_DICT = '}' # push empty dict
APPENDS = 'e' # extend list on stack by topmost stack slice
GET = 'g' # push item from memo on stack; index is string arg
BINGET = 'h' # " " " " " " ; " " 1-byte arg
INST = 'i' # build & push class instance
LONG_BINGET = 'j' # push item from memo on stack; index is 4-byte arg
LIST = 'l' # build list from topmost stack items
EMPTY_LIST = ']' # push empty list
OBJ = 'o' # build & push class instance
PUT = 'p' # store stack top in memo; index is string arg
BINPUT = 'q' # " " " " " ; " " 1-byte arg
LONG_BINPUT = 'r' # " " " " " ; " " 4-byte arg
SETITEM = 's' # add key+value pair to dict
TUPLE = 't' # build tuple from topmost stack items
EMPTY_TUPLE = ')' # push empty tuple
SETITEMS = 'u' # modify dict by adding topmost key+value pairs
BINFLOAT = 'G' # push float; arg is 8-byte float encoding
TRUE = 'I01\n' # not an opcode; see INT docs in pickletools.py
FALSE = 'I00\n' # not an opcode; see INT docs in pickletools.py
# Protocol 2 (not yet implemented).
PROTO = '\x80' # identify pickle protocol
NEWOBJ = '\x81' # build object by applying cls.__new__ to argtuple
EXT1 = '\x82' # push object from extension registry; 1-byte index
EXT2 = '\x83' # ditto, but 2-byte index
EXT4 = '\x84' # ditto, but 4-byte index
TUPLE1 = '\x85' # build 1-tuple from stack top
TUPLE2 = '\x86' # build 2-tuple from two topmost stack items
TUPLE3 = '\x87' # build 3-tuple from three topmost stack items
NEWTRUE = '\x88' # push True
NEWFALSE = '\x89' # push False
LONG1 = '\x8a' # push long from < 256 bytes
LONG4 = '\x8b' # push really big long
_tuplesize2code = [EMPTY_TUPLE, TUPLE1, TUPLE2, TUPLE3]
__all__.extend([x for x in dir() if re.match("[A-Z][A-Z0-9_]+$",x)])
del x
_quotes = ["'", '"']
class Pickler:
def __init__(self, file, proto=1):
"""This takes a file-like object for writing a pickle data stream.
The optional proto argument tells the pickler to use the given
protocol; supported protocols are 0, 1, 2. The default
protocol is 1 (in previous Python versions the default was 0).
Protocol 1 is more efficient than protocol 0; protocol 2 is
more efficient than protocol 1. Protocol 2 is not the default
because it is not supported by older Python versions.
XXX Protocol 2 is not yet implemented.
The file parameter must have a write() method that accepts a single
string argument. It can thus be an open file object, a StringIO
object, or any other custom object that meets this interface.
"""
if not 0 <= proto <= 2:
raise ValueError, "pickle protocol must be 0, 1 or 2"
self.write = file.write
self.memo = {}
self.proto = proto
self.bin = proto >= 1
def clear_memo(self):
"""Clears the pickler's "memo".
The memo is the data structure that remembers which objects the
pickler has already seen, so that shared or recursive objects are
pickled by reference and not by value. This method is useful when
re-using picklers.
"""
self.memo.clear()
def dump(self, object):
"""Write a pickled representation of object to the open file object.
Either the binary or ASCII format will be used, depending on the
value of the bin flag passed to the constructor.
"""
if self.proto >= 2:
self.write(PROTO + chr(self.proto))
self.save(object)
self.write(STOP)
def memoize(self, obj):
"""Store an object in the memo."""
# The Pickler memo is a dictionary mapping object ids to 2-tuples
# that contain the Unpickler memo key and the object being memoized.
# The memo key is written to the pickle and will become
# the key in the Unpickler's memo. The object is stored in the
# Pickler memo so that transient objects are kept alive during
# pickling.
# The use of the Unpickler memo length as the memo key is just a
# convention. The only requirement is that the memo values be unique.
# But there appears no advantage to any other scheme, and this
# scheme allows the Unpickler memo to be implemented as a plain (but
# growable) array, indexed by memo key.
memo_len = len(self.memo)
self.write(self.put(memo_len))
self.memo[id(obj)] = memo_len, obj
# Return a PUT (BINPUT, LONG_BINPUT) opcode string, with argument i.
def put(self, i, pack=struct.pack):
if self.bin:
if i < 256:
return BINPUT + chr(i)
else:
return LONG_BINPUT + pack("<i", i)
return PUT + `i` + '\n'
# Return a GET (BINGET, LONG_BINGET) opcode string, with argument i.
def get(self, i, pack=struct.pack):
if self.bin:
if i < 256:
return BINGET + chr(i)
else:
return LONG_BINGET + pack("<i", i)
return GET + `i` + '\n'
def save(self, object):
memo = self.memo
pid = self.persistent_id(object)
if pid is not None:
self.save_pers(pid)
return
d = id(object)
t = type(object)
if d in memo:
self.write(self.get(memo[d][0]))
return
try:
f = self.dispatch[t]
except KeyError:
pass
else:
f(self, object)
return
# The dispatch table doesn't know about type t.
try:
issc = issubclass(t, TypeType)
except TypeError: # t is not a class
issc = 0
if issc:
self.save_global(object)
return
try:
reduce = dispatch_table[t]
except KeyError:
try:
reduce = object.__reduce__
except AttributeError:
raise PicklingError, \
"can't pickle %s object: %s" % (`t.__name__`,
`object`)
else:
tup = reduce()
else:
tup = reduce(object)
if type(tup) is StringType:
self.save_global(object, tup)
return
if type(tup) is not TupleType:
raise PicklingError, "Value returned by %s must be a " \
"tuple" % reduce
l = len(tup)
if (l != 2) and (l != 3):
raise PicklingError, "tuple returned by %s must contain " \
"only two or three elements" % reduce
callable = tup[0]
arg_tup = tup[1]
if l > 2:
state = tup[2]
else:
state = None
if type(arg_tup) is not TupleType and arg_tup is not None:
raise PicklingError, "Second element of tuple returned " \
"by %s must be a tuple" % reduce
self.save_reduce(callable, arg_tup, state)
self.memoize(object)
def persistent_id(self, object):
return None
def save_pers(self, pid):
if self.bin:
self.save(pid)
self.write(BINPERSID)
else:
self.write(PERSID + str(pid) + '\n')
def save_reduce(self, acallable, arg_tup, state = None):
write = self.write
save = self.save
if not callable(acallable):
raise PicklingError("__reduce__() must return callable as "
"first argument, not %s" % `acallable`)
save(acallable)
save(arg_tup)
write(REDUCE)
if state is not None:
save(state)
write(BUILD)
dispatch = {}
def save_none(self, object):
self.write(NONE)
dispatch[NoneType] = save_none
def save_bool(self, object):
if self.proto >= 2:
self.write(object and NEWTRUE or NEWFALSE)
else:
self.write(object and TRUE or FALSE)
dispatch[bool] = save_bool
def save_int(self, object, pack=struct.pack):
if self.bin:
# If the int is small enough to fit in a signed 4-byte 2's-comp
# format, we can store it more efficiently than the general
# case.
# First one- and two-byte unsigned ints:
if object >= 0:
if object <= 0xff:
self.write(BININT1 + chr(object))
return
if object <= 0xffff:
self.write(BININT2 + chr(object&0xff) + chr(object>>8))
return
# Next check for 4-byte signed ints:
high_bits = object >> 31 # note that Python shift sign-extends
if high_bits == 0 or high_bits == -1:
# All high bits are copies of bit 2**31, so the value
# fits in a 4-byte signed int.
self.write(BININT + pack("<i", object))
return
# Text pickle, or int too big to fit in signed 4-byte format.
self.write(INT + `object` + '\n')
dispatch[IntType] = save_int
def save_long(self, object, pack=struct.pack):
if self.proto >= 2:
bytes = encode_long(object)
n = len(bytes)
if n < 256:
self.write(LONG1 + chr(n) + bytes)
else:
self.write(LONG4 + pack("<i", n) + bytes)
self.write(LONG + `object` + '\n')
dispatch[LongType] = save_long
def save_float(self, object, pack=struct.pack):
if self.bin:
self.write(BINFLOAT + pack('>d', object))
else:
self.write(FLOAT + `object` + '\n')
dispatch[FloatType] = save_float
def save_string(self, object, pack=struct.pack):
if self.bin:
n = len(object)
if n < 256:
self.write(SHORT_BINSTRING + chr(n) + object)
else:
self.write(BINSTRING + pack("<i", n) + object)
else:
self.write(STRING + `object` + '\n')
self.memoize(object)
dispatch[StringType] = save_string
def save_unicode(self, object, pack=struct.pack):
if self.bin:
encoding = object.encode('utf-8')
n = len(encoding)
self.write(BINUNICODE + pack("<i", n) + encoding)
else:
object = object.replace("\\", "\\u005c")
object = object.replace("\n", "\\u000a")
self.write(UNICODE + object.encode('raw-unicode-escape') + '\n')
self.memoize(object)
dispatch[UnicodeType] = save_unicode
if StringType == UnicodeType:
# This is true for Jython
def save_string(self, object, pack=struct.pack):
unicode = object.isunicode()
if self.bin:
if unicode:
object = object.encode("utf-8")
l = len(object)
if l < 256 and not unicode:
self.write(SHORT_BINSTRING + chr(l) + object)
else:
s = pack("<i", l)
if unicode:
self.write(BINUNICODE + s + object)
else:
self.write(BINSTRING + s + object)
else:
if unicode:
object = object.replace("\\", "\\u005c")
object = object.replace("\n", "\\u000a")
object = object.encode('raw-unicode-escape')
self.write(UNICODE + object + '\n')
else:
self.write(STRING + `object` + '\n')
self.memoize(object)
dispatch[StringType] = save_string
def save_tuple(self, object):
write = self.write
proto = self.proto
n = len(object)
if n == 0 and proto:
write(EMPTY_TUPLE)
return
save = self.save
memo = self.memo
if n <= 3 and proto >= 2:
for element in object:
save(element)
# Subtle. Same as in the big comment below.
if id(object) in memo:
get = self.get(memo[id(object)][0])
write(POP * n + get)
else:
write(_tuplesize2code[n])
self.memoize(object)
return
# proto 0, or proto 1 and tuple isn't empty, or proto > 1 and tuple
# has more than 3 elements.
write(MARK)
for element in object:
save(element)
if n and id(object) in memo:
# Subtle. d was not in memo when we entered save_tuple(), so
# the process of saving the tuple's elements must have saved
# the tuple itself: the tuple is recursive. The proper action
# now is to throw away everything we put on the stack, and
# simply GET the tuple (it's already constructed). This check
# could have been done in the "for element" loop instead, but
# recursive tuples are a rare thing.
get = self.get(memo[id(object)][0])
if proto:
write(POP_MARK + get)
else: # proto 0 -- POP_MARK not available
write(POP * (n+1) + get)
return
# No recursion (including the empty-tuple case for protocol 0).
self.write(TUPLE)
self.memoize(object) # XXX shouldn't memoize empty tuple?!
dispatch[TupleType] = save_tuple
def save_empty_tuple(self, object):
self.write(EMPTY_TUPLE)
def save_list(self, object):
write = self.write
save = self.save
if self.bin:
write(EMPTY_LIST)
self.memoize(object)
n = len(object)
if n > 1:
write(MARK)
for element in object:
save(element)
write(APPENDS)
elif n:
assert n == 1
save(object[0])
write(APPEND)
# else the list is empty, and we're already done
else: # proto 0 -- can't use EMPTY_LIST or APPENDS
write(MARK + LIST)
self.memoize(object)
for element in object:
save(element)
write(APPEND)
dispatch[ListType] = save_list
def save_dict(self, object):
write = self.write
save = self.save
items = object.iteritems()
if self.bin:
write(EMPTY_DICT)
self.memoize(object)
if len(object) > 1:
write(MARK)
for key, value in items:
save(key)
save(value)
write(SETITEMS)
return
else: # proto 0 -- can't use EMPTY_DICT or SETITEMS
write(MARK + DICT)
self.memoize(object)
# proto 0 or len(object) < 2
for key, value in items:
save(key)
save(value)
write(SETITEM)
dispatch[DictionaryType] = save_dict
if not PyStringMap is None:
dispatch[PyStringMap] = save_dict
def save_inst(self, object):
cls = object.__class__
memo = self.memo
write = self.write
save = self.save
if hasattr(object, '__getinitargs__'):
args = object.__getinitargs__()
len(args) # XXX Assert it's a sequence
_keep_alive(args, memo)
else:
args = ()
write(MARK)
if self.bin:
save(cls)
for arg in args:
save(arg)
write(OBJ)
else:
for arg in args:
save(arg)
write(INST + cls.__module__ + '\n' + cls.__name__ + '\n')
self.memoize(object)
try:
getstate = object.__getstate__
except AttributeError:
stuff = object.__dict__
else:
stuff = getstate()
_keep_alive(stuff, memo)
save(stuff)
write(BUILD)
dispatch[InstanceType] = save_inst
def save_global(self, object, name = None):
write = self.write
memo = self.memo
if name is None:
name = object.__name__
try:
module = object.__module__
except AttributeError:
module = whichmodule(object, name)
try:
__import__(module)
mod = sys.modules[module]
klass = getattr(mod, name)
except (ImportError, KeyError, AttributeError):
raise PicklingError(
"Can't pickle %r: it's not found as %s.%s" %
(object, module, name))
else:
if klass is not object:
raise PicklingError(
"Can't pickle %r: it's not the same object as %s.%s" %
(object, module, name))
write(GLOBAL + module + '\n' + name + '\n')
self.memoize(object)
dispatch[ClassType] = save_global
dispatch[FunctionType] = save_global
dispatch[BuiltinFunctionType] = save_global
dispatch[TypeType] = save_global
def _keep_alive(x, memo):
"""Keeps a reference to the object x in the memo.
Because we remember objects by their id, we have
to assure that possibly temporary objects are kept
alive by referencing them.
We store a reference at the id of the memo, which should
normally not be used unless someone tries to deepcopy
the memo itself...
"""
try:
memo[id(memo)].append(x)
except KeyError:
# aha, this is the first one :-)
memo[id(memo)]=[x]
classmap = {} # called classmap for backwards compatibility
def whichmodule(func, funcname):
"""Figure out the module in which a function occurs.
Search sys.modules for the module.
Cache in classmap.
Return a module name.
If the function cannot be found, return __main__.
"""
if func in classmap:
return classmap[func]
for name, module in sys.modules.items():
if module is None:
continue # skip dummy package entries
if name != '__main__' and \
hasattr(module, funcname) and \
getattr(module, funcname) is func:
break
else:
name = '__main__'
classmap[func] = name
return name
class Unpickler:
def __init__(self, file):
"""This takes a file-like object for reading a pickle data stream.
This class automatically determines whether the data stream was
written in binary mode or not, so it does not need a flag as in
the Pickler class factory.
The file-like object must have two methods, a read() method that
takes an integer argument, and a readline() method that requires no
arguments. Both methods should return a string. Thus file-like
object can be a file object opened for reading, a StringIO object,
or any other custom object that meets this interface.
"""
self.readline = file.readline
self.read = file.read
self.memo = {}
def load(self):
"""Read a pickled object representation from the open file object.
Return the reconstituted object hierarchy specified in the file
object.
"""
self.mark = object() # any new unique object
self.stack = []
self.append = self.stack.append
read = self.read
dispatch = self.dispatch
try:
while 1:
key = read(1)
dispatch[key](self)
except _Stop, stopinst:
return stopinst.value
# Return largest index k such that self.stack[k] is self.mark.
# If the stack doesn't contain a mark, eventually raises IndexError.
# This could be sped by maintaining another stack, of indices at which
# the mark appears. For that matter, the latter stack would suffice,
# and we wouldn't need to push mark objects on self.stack at all.
# Doing so is probably a good thing, though, since if the pickle is
# corrupt (or hostile) we may get a clue from finding self.mark embedded
# in unpickled objects.
def marker(self):
stack = self.stack
mark = self.mark
k = len(stack)-1
while stack[k] is not mark: k = k-1
return k
dispatch = {}
def load_eof(self):
raise EOFError
dispatch[''] = load_eof
def load_proto(self):
proto = ord(self.read(1))
if not 0 <= proto <= 2:
raise ValueError, "unsupported pickle protocol: %d" % proto
dispatch[PROTO] = load_proto
def load_persid(self):
pid = self.readline()[:-1]
self.append(self.persistent_load(pid))
dispatch[PERSID] = load_persid
def load_binpersid(self):
pid = self.stack.pop()
self.append(self.persistent_load(pid))
dispatch[BINPERSID] = load_binpersid
def load_none(self):
self.append(None)
dispatch[NONE] = load_none
def load_false(self):
self.append(False)
dispatch[NEWFALSE] = load_false
def load_true(self):
self.append(True)
dispatch[NEWTRUE] = load_true
def load_int(self):
data = self.readline()
if data == FALSE[1:]:
val = False
elif data == TRUE[1:]:
val = True
else:
try:
val = int(data)
except ValueError:
val = long(data)
self.append(val)
dispatch[INT] = load_int
def load_binint(self):
self.append(mloads('i' + self.read(4)))
dispatch[BININT] = load_binint
def load_binint1(self):
self.append(ord(self.read(1)))
dispatch[BININT1] = load_binint1
def load_binint2(self):
self.append(mloads('i' + self.read(2) + '\000\000'))
dispatch[BININT2] = load_binint2
def load_long(self):
self.append(long(self.readline()[:-1], 0))
dispatch[LONG] = load_long
def load_long1(self):
n = ord(self.read(1))
bytes = self.read(n)
return decode_long(bytes)
dispatch[LONG1] = load_long1
def load_long4(self):
n = mloads('i' + self.read(4))
bytes = self.read(n)
return decode_long(bytes)
dispatch[LONG4] = load_long4
def load_float(self):
self.append(float(self.readline()[:-1]))
dispatch[FLOAT] = load_float
def load_binfloat(self, unpack=struct.unpack):
self.append(unpack('>d', self.read(8))[0])
dispatch[BINFLOAT] = load_binfloat
def load_string(self):
rep = self.readline()[:-1]
for q in _quotes:
if rep.startswith(q):
if not rep.endswith(q):
raise ValueError, "insecure string pickle"
rep = rep[len(q):-len(q)]
break
else:
raise ValueError, "insecure string pickle"
self.append(rep.decode("string-escape"))
dispatch[STRING] = load_string
def _is_string_secure(self, s):
"""Return true if s contains a string that is safe to eval
The definition of secure string is based on the implementation
in cPickle. s is secure as long as it only contains a quoted
string and optional trailing whitespace.
"""
q = s[0]
if q not in ("'", '"'):
return 0
# find the closing quote
offset = 1
i = None
while 1:
try:
i = s.index(q, offset)
except ValueError:
# if there is an error the first time, there is no
# close quote
if offset == 1:
return 0
if s[i-1] != '\\':
break
# check to see if this one is escaped
nslash = 0
j = i - 1
while j >= offset and s[j] == '\\':
j = j - 1
nslash = nslash + 1
if nslash % 2 == 0:
break
offset = i + 1
for c in s[i+1:]:
if ord(c) > 32:
return 0
return 1
def load_binstring(self):
len = mloads('i' + self.read(4))
self.append(self.read(len))
dispatch[BINSTRING] = load_binstring
def load_unicode(self):
self.append(unicode(self.readline()[:-1],'raw-unicode-escape'))
dispatch[UNICODE] = load_unicode
def load_binunicode(self):
len = mloads('i' + self.read(4))
self.append(unicode(self.read(len),'utf-8'))
dispatch[BINUNICODE] = load_binunicode
def load_short_binstring(self):
len = ord(self.read(1))
self.append(self.read(len))
dispatch[SHORT_BINSTRING] = load_short_binstring
def load_tuple(self):
k = self.marker()
self.stack[k:] = [tuple(self.stack[k+1:])]
dispatch[TUPLE] = load_tuple
def load_empty_tuple(self):
self.stack.append(())
dispatch[EMPTY_TUPLE] = load_empty_tuple
def load_tuple1(self):
self.stack[-1] = (self.stack[-1],)
dispatch[TUPLE1] = load_tuple1
def load_tuple2(self):
self.stack[-2:] = [(self.stack[-2], self.stack[-1])]
dispatch[TUPLE2] = load_tuple2
def load_tuple3(self):
self.stack[-3:] = [(self.stack[-3], self.stack[-2], self.stack[-1])]
dispatch[TUPLE3] = load_tuple3
def load_empty_list(self):
self.stack.append([])
dispatch[EMPTY_LIST] = load_empty_list
def load_empty_dictionary(self):
self.stack.append({})
dispatch[EMPTY_DICT] = load_empty_dictionary
def load_list(self):
k = self.marker()
self.stack[k:] = [self.stack[k+1:]]
dispatch[LIST] = load_list
def load_dict(self):
k = self.marker()
d = {}
items = self.stack[k+1:]
for i in range(0, len(items), 2):
key = items[i]
value = items[i+1]
d[key] = value
self.stack[k:] = [d]
dispatch[DICT] = load_dict
def load_inst(self):
k = self.marker()
args = tuple(self.stack[k+1:])
del self.stack[k:]
module = self.readline()[:-1]
name = self.readline()[:-1]
klass = self.find_class(module, name)
instantiated = 0
if (not args and type(klass) is ClassType and
not hasattr(klass, "__getinitargs__")):
try:
value = _EmptyClass()
value.__class__ = klass
instantiated = 1
except RuntimeError:
# In restricted execution, assignment to inst.__class__ is
# prohibited
pass
if not instantiated:
try:
if not hasattr(klass, '__safe_for_unpickling__'):
raise UnpicklingError('%s is not safe for unpickling' %
klass)
value = apply(klass, args)
except TypeError, err:
raise TypeError, "in constructor for %s: %s" % (
klass.__name__, str(err)), sys.exc_info()[2]
self.append(value)
dispatch[INST] = load_inst
def load_obj(self):
stack = self.stack
k = self.marker()
klass = stack[k + 1]
del stack[k + 1]
args = tuple(stack[k + 1:])
del stack[k:]
instantiated = 0
if (not args and type(klass) is ClassType and
not hasattr(klass, "__getinitargs__")):
try:
value = _EmptyClass()
value.__class__ = klass
instantiated = 1
except RuntimeError:
# In restricted execution, assignment to inst.__class__ is
# prohibited
pass
if not instantiated:
value = apply(klass, args)
self.append(value)
dispatch[OBJ] = load_obj
def load_global(self):
module = self.readline()[:-1]
name = self.readline()[:-1]
klass = self.find_class(module, name)
self.append(klass)
dispatch[GLOBAL] = load_global
def find_class(self, module, name):
__import__(module)
mod = sys.modules[module]
klass = getattr(mod, name)
return klass
def load_reduce(self):
stack = self.stack
callable = stack[-2]
arg_tup = stack[-1]
del stack[-2:]
if type(callable) is not ClassType:
if not callable in safe_constructors:
try:
safe = callable.__safe_for_unpickling__
except AttributeError:
safe = None
if not safe:
raise UnpicklingError, "%s is not safe for " \
"unpickling" % callable
if arg_tup is None:
import warnings
warnings.warn("The None return argument form of __reduce__ is "
"deprecated. Return a tuple of arguments instead.",
DeprecationWarning)
value = callable.__basicnew__()
else:
value = apply(callable, arg_tup)
self.append(value)
dispatch[REDUCE] = load_reduce
def load_pop(self):
del self.stack[-1]
dispatch[POP] = load_pop
def load_pop_mark(self):
k = self.marker()
del self.stack[k:]
dispatch[POP_MARK] = load_pop_mark
def load_dup(self):
self.append(self.stack[-1])
dispatch[DUP] = load_dup
def load_get(self):
self.append(self.memo[self.readline()[:-1]])
dispatch[GET] = load_get
def load_binget(self):
i = ord(self.read(1))
self.append(self.memo[`i`])
dispatch[BINGET] = load_binget
def load_long_binget(self):
i = mloads('i' + self.read(4))
self.append(self.memo[`i`])
dispatch[LONG_BINGET] = load_long_binget
def load_put(self):
self.memo[self.readline()[:-1]] = self.stack[-1]
dispatch[PUT] = load_put
def load_binput(self):
i = ord(self.read(1))
self.memo[`i`] = self.stack[-1]
dispatch[BINPUT] = load_binput
def load_long_binput(self):
i = mloads('i' + self.read(4))
self.memo[`i`] = self.stack[-1]
dispatch[LONG_BINPUT] = load_long_binput
def load_append(self):
stack = self.stack
value = stack.pop()
list = stack[-1]
list.append(value)
dispatch[APPEND] = load_append
def load_appends(self):
stack = self.stack
mark = self.marker()
list = stack[mark - 1]
list.extend(stack[mark + 1:])
del stack[mark:]
dispatch[APPENDS] = load_appends
def load_setitem(self):
stack = self.stack
value = stack.pop()
key = stack.pop()
dict = stack[-1]
dict[key] = value
dispatch[SETITEM] = load_setitem
def load_setitems(self):
stack = self.stack
mark = self.marker()
dict = stack[mark - 1]
for i in range(mark + 1, len(stack), 2):
dict[stack[i]] = stack[i + 1]
del stack[mark:]
dispatch[SETITEMS] = load_setitems
def load_build(self):
stack = self.stack
value = stack.pop()
inst = stack[-1]
try:
setstate = inst.__setstate__
except AttributeError:
try:
inst.__dict__.update(value)
except RuntimeError:
# XXX In restricted execution, the instance's __dict__ is not
# accessible. Use the old way of unpickling the instance
# variables. This is a semantic different when unpickling in
# restricted vs. unrestricted modes.
for k, v in value.items():
setattr(inst, k, v)
else:
setstate(value)
dispatch[BUILD] = load_build
def load_mark(self):
self.append(self.mark)
dispatch[MARK] = load_mark
def load_stop(self):
value = self.stack.pop()
raise _Stop(value)
dispatch[STOP] = load_stop
# Helper class for load_inst/load_obj
class _EmptyClass:
pass
# Encode/decode longs.
def encode_long(x):
r"""Encode a long to a two's complement little-ending binary string.
>>> encode_long(255L)
'\xff\x00'
>>> encode_long(32767L)
'\xff\x7f'
>>> encode_long(-256L)
'\x00\xff'
>>> encode_long(-32768L)
'\x00\x80'
>>> encode_long(-128L)
'\x80'
>>> encode_long(127L)
'\x7f'
>>>
"""
digits = []
while not -128 <= x < 128:
digits.append(x & 0xff)
x >>= 8
digits.append(x & 0xff)
return "".join(map(chr, digits))
def decode_long(data):
r"""Decode a long from a two's complement little-endian binary string.
>>> decode_long("\xff\x00")
255L
>>> decode_long("\xff\x7f")
32767L
>>> decode_long("\x00\xff")
-256L
>>> decode_long("\x00\x80")
-32768L
>>> decode_long("\x80")
-128L
>>> decode_long("\x7f")
127L
"""
x = 0L
i = 0L
for c in data:
x |= long(ord(c)) << i
i += 8L
if data and ord(c) >= 0x80:
x -= 1L << i
return x
# Shorthands
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
def dump(object, file, proto=1):
Pickler(file, proto).dump(object)
def dumps(object, proto=1):
file = StringIO()
Pickler(file, proto).dump(object)
return file.getvalue()
def load(file):
return Unpickler(file).load()
def loads(str):
file = StringIO(str)
return Unpickler(file).load()
# Doctest
def _test():
import doctest
return doctest.testmod()
if __name__ == "__main__":
_test()
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