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cpython/Lib/pickle.py

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"""Create portable serialized representations of Python objects.
See module copyreg 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
"""
from types import FunctionType, BuiltinFunctionType
from copyreg import dispatch_table
from copyreg import _extension_registry, _inverted_registry, _extension_cache
import marshal
import sys
import struct
import re
import io
import codecs
import _compat_pickle
__all__ = ["PickleError", "PicklingError", "UnpicklingError", "Pickler",
"Unpickler", "dump", "dumps", "load", "loads"]
# Shortcut for use in isinstance testing
bytes_types = (bytes, bytearray)
# These are purely informational; no code uses these.
format_version = "3.0" # File format version we write
compatible_formats = ["1.0", # Original protocol 0
"1.1", # Protocol 0 with INST added
"1.2", # Original protocol 1
"1.3", # Protocol 1 with BINFLOAT added
"2.0", # Protocol 2
"3.0", # Protocol 3
] # Old format versions we can read
# This is the highest protocol number we know how to read.
HIGHEST_PROTOCOL = 3
# The protocol we write by default. May be less than HIGHEST_PROTOCOL.
# We intentionally write a protocol that Python 2.x cannot read;
# there are too many issues with that.
DEFAULT_PROTOCOL = 3
# Why use struct.pack() for pickling but marshal.loads() for
# unpickling? struct.pack() is 40% faster than marshal.dumps(), 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
# An instance of _Stop is raised by Unpickler.load_stop() in response to
# the STOP opcode, passing the object that is the result of unpickling.
class _Stop(Exception):
def __init__(self, value):
self.value = value
# Jython has PyStringMap; it's a dict subclass with string keys
try:
from org.python.core import PyStringMap
except ImportError:
PyStringMap = 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 = b'(' # push special markobject on stack
STOP = b'.' # every pickle ends with STOP
POP = b'0' # discard topmost stack item
POP_MARK = b'1' # discard stack top through topmost markobject
DUP = b'2' # duplicate top stack item
FLOAT = b'F' # push float object; decimal string argument
INT = b'I' # push integer or bool; decimal string argument
BININT = b'J' # push four-byte signed int
BININT1 = b'K' # push 1-byte unsigned int
LONG = b'L' # push long; decimal string argument
BININT2 = b'M' # push 2-byte unsigned int
NONE = b'N' # push None
PERSID = b'P' # push persistent object; id is taken from string arg
BINPERSID = b'Q' # " " " ; " " " " stack
REDUCE = b'R' # apply callable to argtuple, both on stack
STRING = b'S' # push string; NL-terminated string argument
BINSTRING = b'T' # push string; counted binary string argument
SHORT_BINSTRING= b'U' # " " ; " " " " < 256 bytes
UNICODE = b'V' # push Unicode string; raw-unicode-escaped'd argument
BINUNICODE = b'X' # " " " ; counted UTF-8 string argument
APPEND = b'a' # append stack top to list below it
BUILD = b'b' # call __setstate__ or __dict__.update()
GLOBAL = b'c' # push self.find_class(modname, name); 2 string args
DICT = b'd' # build a dict from stack items
EMPTY_DICT = b'}' # push empty dict
APPENDS = b'e' # extend list on stack by topmost stack slice
GET = b'g' # push item from memo on stack; index is string arg
BINGET = b'h' # " " " " " " ; " " 1-byte arg
INST = b'i' # build & push class instance
LONG_BINGET = b'j' # push item from memo on stack; index is 4-byte arg
LIST = b'l' # build list from topmost stack items
EMPTY_LIST = b']' # push empty list
OBJ = b'o' # build & push class instance
PUT = b'p' # store stack top in memo; index is string arg
BINPUT = b'q' # " " " " " ; " " 1-byte arg
LONG_BINPUT = b'r' # " " " " " ; " " 4-byte arg
SETITEM = b's' # add key+value pair to dict
TUPLE = b't' # build tuple from topmost stack items
EMPTY_TUPLE = b')' # push empty tuple
SETITEMS = b'u' # modify dict by adding topmost key+value pairs
BINFLOAT = b'G' # push float; arg is 8-byte float encoding
TRUE = b'I01\n' # not an opcode; see INT docs in pickletools.py
FALSE = b'I00\n' # not an opcode; see INT docs in pickletools.py
# Protocol 2
PROTO = b'\x80' # identify pickle protocol
NEWOBJ = b'\x81' # build object by applying cls.__new__ to argtuple
EXT1 = b'\x82' # push object from extension registry; 1-byte index
EXT2 = b'\x83' # ditto, but 2-byte index
EXT4 = b'\x84' # ditto, but 4-byte index
TUPLE1 = b'\x85' # build 1-tuple from stack top
TUPLE2 = b'\x86' # build 2-tuple from two topmost stack items
TUPLE3 = b'\x87' # build 3-tuple from three topmost stack items
NEWTRUE = b'\x88' # push True
NEWFALSE = b'\x89' # push False
LONG1 = b'\x8a' # push long from < 256 bytes
LONG4 = b'\x8b' # push really big long
_tuplesize2code = [EMPTY_TUPLE, TUPLE1, TUPLE2, TUPLE3]
# Protocol 3 (Python 3.x)
BINBYTES = b'B' # push bytes; counted binary string argument
SHORT_BINBYTES = b'C' # " " ; " " " " < 256 bytes
__all__.extend([x for x in dir() if re.match("[A-Z][A-Z0-9_]+$",x)])
# Pickling machinery
class _Pickler:
def __init__(self, file, protocol=None, *, fix_imports=True):
"""This takes a binary file for writing a pickle data stream.
The optional protocol argument tells the pickler to use the
given protocol; supported protocols are 0, 1, 2, 3. The default
protocol is 3; a backward-incompatible protocol designed for
Python 3.0.
Specifying a negative protocol version selects the highest
protocol version supported. The higher the protocol used, the
more recent the version of Python needed to read the pickle
produced.
The file argument must have a write() method that accepts a single
bytes argument. It can thus be a file object opened for binary
writing, a io.BytesIO instance, or any other custom object that
meets this interface.
If fix_imports is True and protocol is less than 3, pickle will try to
map the new Python 3.x names to the old module names used in Python
2.x, so that the pickle data stream is readable with Python 2.x.
"""
if protocol is None:
protocol = DEFAULT_PROTOCOL
if protocol < 0:
protocol = HIGHEST_PROTOCOL
elif not 0 <= protocol <= HIGHEST_PROTOCOL:
raise ValueError("pickle protocol must be <= %d" % HIGHEST_PROTOCOL)
try:
self.write = file.write
except AttributeError:
raise TypeError("file must have a 'write' attribute")
self.memo = {}
self.proto = int(protocol)
self.bin = protocol >= 1
self.fast = 0
self.fix_imports = fix_imports and protocol < 3
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, obj):
"""Write a pickled representation of obj to the open file."""
# Check whether Pickler was initialized correctly. This is
# only needed to mimic the behavior of _pickle.Pickler.dump().
if not hasattr(self, "write"):
raise PicklingError("Pickler.__init__() was not called by "
"%s.__init__()" % (self.__class__.__name__,))
if self.proto >= 2:
self.write(PROTO + bytes([self.proto]))
self.save(obj)
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.
if self.fast:
return
assert id(obj) not in self.memo
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 + bytes([i])
else:
return LONG_BINPUT + pack("<I", i)
return PUT + repr(i).encode("ascii") + b'\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 + bytes([i])
else:
return LONG_BINGET + pack("<I", i)
return GET + repr(i).encode("ascii") + b'\n'
def save(self, obj, save_persistent_id=True):
# Check for persistent id (defined by a subclass)
pid = self.persistent_id(obj)
if pid is not None and save_persistent_id:
self.save_pers(pid)
return
# Check the memo
x = self.memo.get(id(obj))
if x:
self.write(self.get(x[0]))
return
# Check the type dispatch table
t = type(obj)
f = self.dispatch.get(t)
if f:
f(self, obj) # Call unbound method with explicit self
return
# Check private dispatch table if any, or else copyreg.dispatch_table
reduce = getattr(self, 'dispatch_table', dispatch_table).get(t)
if reduce:
rv = reduce(obj)
else:
# Check for a class with a custom metaclass; treat as regular class
try:
issc = issubclass(t, type)
except TypeError: # t is not a class (old Boost; see SF #502085)
issc = False
if issc:
self.save_global(obj)
return
# Check for a __reduce_ex__ method, fall back to __reduce__
reduce = getattr(obj, "__reduce_ex__", None)
if reduce:
rv = reduce(self.proto)
else:
reduce = getattr(obj, "__reduce__", None)
if reduce:
rv = reduce()
else:
raise PicklingError("Can't pickle %r object: %r" %
(t.__name__, obj))
# Check for string returned by reduce(), meaning "save as global"
if isinstance(rv, str):
self.save_global(obj, rv)
return
# Assert that reduce() returned a tuple
if not isinstance(rv, tuple):
raise PicklingError("%s must return string or tuple" % reduce)
# Assert that it returned an appropriately sized tuple
l = len(rv)
if not (2 <= l <= 5):
raise PicklingError("Tuple returned by %s must have "
"two to five elements" % reduce)
# Save the reduce() output and finally memoize the object
self.save_reduce(obj=obj, *rv)
def persistent_id(self, obj):
# This exists so a subclass can override it
return None
def save_pers(self, pid):
# Save a persistent id reference
if self.bin:
self.save(pid, save_persistent_id=False)
self.write(BINPERSID)
else:
self.write(PERSID + str(pid).encode("ascii") + b'\n')
def save_reduce(self, func, args, state=None,
listitems=None, dictitems=None, obj=None):
# This API is called by some subclasses
# Assert that args is a tuple
if not isinstance(args, tuple):
raise PicklingError("args from save_reduce() should be a tuple")
# Assert that func is callable
if not callable(func):
raise PicklingError("func from save_reduce() should be callable")
save = self.save
write = self.write
# Protocol 2 special case: if func's name is __newobj__, use NEWOBJ
if self.proto >= 2 and getattr(func, "__name__", "") == "__newobj__":
# A __reduce__ implementation can direct protocol 2 to
# use the more efficient NEWOBJ opcode, while still
# allowing protocol 0 and 1 to work normally. For this to
# work, the function returned by __reduce__ should be
# called __newobj__, and its first argument should be a
# class. The implementation for __newobj__
# should be as follows, although pickle has no way to
# verify this:
#
# def __newobj__(cls, *args):
# return cls.__new__(cls, *args)
#
# Protocols 0 and 1 will pickle a reference to __newobj__,
# while protocol 2 (and above) will pickle a reference to
# cls, the remaining args tuple, and the NEWOBJ code,
# which calls cls.__new__(cls, *args) at unpickling time
# (see load_newobj below). If __reduce__ returns a
# three-tuple, the state from the third tuple item will be
# pickled regardless of the protocol, calling __setstate__
# at unpickling time (see load_build below).
#
# Note that no standard __newobj__ implementation exists;
# you have to provide your own. This is to enforce
# compatibility with Python 2.2 (pickles written using
# protocol 0 or 1 in Python 2.3 should be unpicklable by
# Python 2.2).
cls = args[0]
if not hasattr(cls, "__new__"):
raise PicklingError(
"args[0] from __newobj__ args has no __new__")
if obj is not None and cls is not obj.__class__:
raise PicklingError(
"args[0] from __newobj__ args has the wrong class")
args = args[1:]
save(cls)
save(args)
write(NEWOBJ)
else:
save(func)
save(args)
write(REDUCE)
if obj is not None:
self.memoize(obj)
# More new special cases (that work with older protocols as
# well): when __reduce__ returns a tuple with 4 or 5 items,
# the 4th and 5th item should be iterators that provide list
# items and dict items (as (key, value) tuples), or None.
if listitems is not None:
self._batch_appends(listitems)
if dictitems is not None:
self._batch_setitems(dictitems)
if state is not None:
save(state)
write(BUILD)
# Methods below this point are dispatched through the dispatch table
dispatch = {}
def save_none(self, obj):
self.write(NONE)
dispatch[type(None)] = save_none
def save_ellipsis(self, obj):
self.save_global(Ellipsis, 'Ellipsis')
dispatch[type(Ellipsis)] = save_ellipsis
def save_notimplemented(self, obj):
self.save_global(NotImplemented, 'NotImplemented')
dispatch[type(NotImplemented)] = save_notimplemented
def save_bool(self, obj):
if self.proto >= 2:
self.write(obj and NEWTRUE or NEWFALSE)
else:
self.write(obj and TRUE or FALSE)
dispatch[bool] = save_bool
def save_long(self, obj, 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 obj >= 0:
if obj <= 0xff:
self.write(BININT1 + bytes([obj]))
return
if obj <= 0xffff:
self.write(BININT2 + bytes([obj&0xff, obj>>8]))
return
# Next check for 4-byte signed ints:
high_bits = obj >> 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", obj))
return
if self.proto >= 2:
encoded = encode_long(obj)
n = len(encoded)
if n < 256:
self.write(LONG1 + bytes([n]) + encoded)
else:
self.write(LONG4 + pack("<i", n) + encoded)
return
self.write(LONG + repr(obj).encode("ascii") + b'L\n')
dispatch[int] = save_long
def save_float(self, obj, pack=struct.pack):
if self.bin:
self.write(BINFLOAT + pack('>d', obj))
else:
self.write(FLOAT + repr(obj).encode("ascii") + b'\n')
dispatch[float] = save_float
def save_bytes(self, obj, pack=struct.pack):
if self.proto < 3:
if len(obj) == 0:
self.save_reduce(bytes, (), obj=obj)
else:
self.save_reduce(codecs.encode,
(str(obj, 'latin1'), 'latin1'), obj=obj)
return
n = len(obj)
if n < 256:
self.write(SHORT_BINBYTES + bytes([n]) + bytes(obj))
else:
self.write(BINBYTES + pack("<I", n) + bytes(obj))
self.memoize(obj)
dispatch[bytes] = save_bytes
def save_str(self, obj, pack=struct.pack):
if self.bin:
encoded = obj.encode('utf-8', 'surrogatepass')
n = len(encoded)
self.write(BINUNICODE + pack("<I", n) + encoded)
else:
obj = obj.replace("\\", "\\u005c")
obj = obj.replace("\n", "\\u000a")
self.write(UNICODE + bytes(obj.encode('raw-unicode-escape')) +
b'\n')
self.memoize(obj)
dispatch[str] = save_str
def save_tuple(self, obj):
write = self.write
proto = self.proto
n = len(obj)
if n == 0:
if proto:
write(EMPTY_TUPLE)
else:
write(MARK + TUPLE)
return
save = self.save
memo = self.memo
if n <= 3 and proto >= 2:
for element in obj:
save(element)
# Subtle. Same as in the big comment below.
if id(obj) in memo:
get = self.get(memo[id(obj)][0])
write(POP * n + get)
else:
write(_tuplesize2code[n])
self.memoize(obj)
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 obj:
save(element)
if id(obj) 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(obj)][0])
if proto:
write(POP_MARK + get)
else: # proto 0 -- POP_MARK not available
write(POP * (n+1) + get)
return
# No recursion.
self.write(TUPLE)
self.memoize(obj)
dispatch[tuple] = save_tuple
def save_list(self, obj):
write = self.write
if self.bin:
write(EMPTY_LIST)
else: # proto 0 -- can't use EMPTY_LIST
write(MARK + LIST)
self.memoize(obj)
self._batch_appends(obj)
dispatch[list] = save_list
_BATCHSIZE = 1000
def _batch_appends(self, items):
# Helper to batch up APPENDS sequences
save = self.save
write = self.write
if not self.bin:
for x in items:
save(x)
write(APPEND)
return
items = iter(items)
r = range(self._BATCHSIZE)
while items is not None:
tmp = []
for i in r:
try:
x = next(items)
tmp.append(x)
except StopIteration:
items = None
break
n = len(tmp)
if n > 1:
write(MARK)
for x in tmp:
save(x)
write(APPENDS)
elif n:
save(tmp[0])
write(APPEND)
# else tmp is empty, and we're done
def save_dict(self, obj):
write = self.write
if self.bin:
write(EMPTY_DICT)
else: # proto 0 -- can't use EMPTY_DICT
write(MARK + DICT)
self.memoize(obj)
self._batch_setitems(obj.items())
dispatch[dict] = save_dict
if PyStringMap is not None:
dispatch[PyStringMap] = save_dict
def _batch_setitems(self, items):
# Helper to batch up SETITEMS sequences; proto >= 1 only
save = self.save
write = self.write
if not self.bin:
for k, v in items:
save(k)
save(v)
write(SETITEM)
return
items = iter(items)
r = range(self._BATCHSIZE)
while items is not None:
tmp = []
for i in r:
try:
tmp.append(next(items))
except StopIteration:
items = None
break
n = len(tmp)
if n > 1:
write(MARK)
for k, v in tmp:
save(k)
save(v)
write(SETITEMS)
elif n:
k, v = tmp[0]
save(k)
save(v)
write(SETITEM)
# else tmp is empty, and we're done
def save_global(self, obj, name=None, pack=struct.pack):
write = self.write
memo = self.memo
if name is None:
name = obj.__name__
module = getattr(obj, "__module__", None)
if module is None:
module = whichmodule(obj, name)
try:
__import__(module, level=0)
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" %
(obj, module, name))
else:
if klass is not obj:
raise PicklingError(
"Can't pickle %r: it's not the same object as %s.%s" %
(obj, module, name))
if self.proto >= 2:
code = _extension_registry.get((module, name))
if code:
assert code > 0
if code <= 0xff:
write(EXT1 + bytes([code]))
elif code <= 0xffff:
write(EXT2 + bytes([code&0xff, code>>8]))
else:
write(EXT4 + pack("<i", code))
return
# Non-ASCII identifiers are supported only with protocols >= 3.
if self.proto >= 3:
write(GLOBAL + bytes(module, "utf-8") + b'\n' +
bytes(name, "utf-8") + b'\n')
else:
if self.fix_imports:
if (module, name) in _compat_pickle.REVERSE_NAME_MAPPING:
module, name = _compat_pickle.REVERSE_NAME_MAPPING[(module, name)]
if module in _compat_pickle.REVERSE_IMPORT_MAPPING:
module = _compat_pickle.REVERSE_IMPORT_MAPPING[module]
try:
write(GLOBAL + bytes(module, "ascii") + b'\n' +
bytes(name, "ascii") + b'\n')
except UnicodeEncodeError:
raise PicklingError(
"can't pickle global identifier '%s.%s' using "
"pickle protocol %i" % (module, name, self.proto))
self.memoize(obj)
dispatch[FunctionType] = save_global
dispatch[BuiltinFunctionType] = save_global
dispatch[type] = save_global
# Pickling helpers
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]
# A cache for whichmodule(), mapping a function object to the name of
# the module in which the function was found.
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__".
"""
# Python functions should always get an __module__ from their globals.
mod = getattr(func, "__module__", None)
if mod is not None:
return mod
if func in classmap:
return classmap[func]
for name, module in list(sys.modules.items()):
if module is None:
continue # skip dummy package entries
if name != '__main__' and getattr(module, funcname, None) is func:
break
else:
name = '__main__'
classmap[func] = name
return name
# Unpickling machinery
class _Unpickler:
def __init__(self, file, *, fix_imports=True,
encoding="ASCII", errors="strict"):
"""This takes a binary file for reading a pickle data stream.
The protocol version of the pickle is detected automatically, so no
proto argument is needed.
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 bytes.
Thus file-like object can be a binary file object opened for
reading, a BytesIO object, or any other custom object that
meets this interface.
Optional keyword arguments are *fix_imports*, *encoding* and *errors*,
which are used to control compatiblity support for pickle stream
generated by Python 2.x. If *fix_imports* is True, pickle will try to
map the old Python 2.x names to the new names used in Python 3.x. The
*encoding* and *errors* tell pickle how to decode 8-bit string
instances pickled by Python 2.x; these default to 'ASCII' and
'strict', respectively.
"""
self.readline = file.readline
self.read = file.read
self.memo = {}
self.encoding = encoding
self.errors = errors
self.proto = 0
self.fix_imports = fix_imports
def load(self):
"""Read a pickled object representation from the open file.
Return the reconstituted object hierarchy specified in the file.
"""
# Check whether Unpickler was initialized correctly. This is
# only needed to mimic the behavior of _pickle.Unpickler.dump().
if not hasattr(self, "read"):
raise UnpicklingError("Unpickler.__init__() was not called by "
"%s.__init__()" % (self.__class__.__name__,))
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)
if not key:
raise EOFError
assert isinstance(key, bytes_types)
dispatch[key[0]](self)
except _Stop as 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
def persistent_load(self, pid):
raise UnpicklingError("unsupported persistent id encountered")
dispatch = {}
def load_proto(self):
proto = ord(self.read(1))
if not 0 <= proto <= HIGHEST_PROTOCOL:
raise ValueError("unsupported pickle protocol: %d" % proto)
self.proto = proto
dispatch[PROTO[0]] = load_proto
def load_persid(self):
pid = self.readline()[:-1].decode("ascii")
self.append(self.persistent_load(pid))
dispatch[PERSID[0]] = load_persid
def load_binpersid(self):
pid = self.stack.pop()
self.append(self.persistent_load(pid))
dispatch[BINPERSID[0]] = load_binpersid
def load_none(self):
self.append(None)
dispatch[NONE[0]] = load_none
def load_false(self):
self.append(False)
dispatch[NEWFALSE[0]] = load_false
def load_true(self):
self.append(True)
dispatch[NEWTRUE[0]] = 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, 0)
except ValueError:
val = int(data, 0)
self.append(val)
dispatch[INT[0]] = load_int
def load_binint(self):
self.append(mloads(b'i' + self.read(4)))
dispatch[BININT[0]] = load_binint
def load_binint1(self):
self.append(ord(self.read(1)))
dispatch[BININT1[0]] = load_binint1
def load_binint2(self):
self.append(mloads(b'i' + self.read(2) + b'\000\000'))
dispatch[BININT2[0]] = load_binint2
def load_long(self):
val = self.readline()[:-1].decode("ascii")
if val and val[-1] == 'L':
val = val[:-1]
self.append(int(val, 0))
dispatch[LONG[0]] = load_long
def load_long1(self):
n = ord(self.read(1))
data = self.read(n)
self.append(decode_long(data))
dispatch[LONG1[0]] = load_long1
def load_long4(self):
n = mloads(b'i' + self.read(4))
if n < 0:
# Corrupt or hostile pickle -- we never write one like this
raise UnpicklingError("LONG pickle has negative byte count");
data = self.read(n)
self.append(decode_long(data))
dispatch[LONG4[0]] = load_long4
def load_float(self):
self.append(float(self.readline()[:-1]))
dispatch[FLOAT[0]] = load_float
def load_binfloat(self, unpack=struct.unpack):
self.append(unpack('>d', self.read(8))[0])
dispatch[BINFLOAT[0]] = load_binfloat
def load_string(self):
orig = self.readline()
rep = orig[:-1]
for q in (b'"', b"'"): # double or single quote
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: %r" % orig)
self.append(codecs.escape_decode(rep)[0]
.decode(self.encoding, self.errors))
dispatch[STRING[0]] = load_string
def load_binstring(self):
# Deprecated BINSTRING uses signed 32-bit length
len = mloads(b'i' + self.read(4))
if len < 0:
raise UnpicklingError("BINSTRING pickle has negative byte count");
data = self.read(len)
value = str(data, self.encoding, self.errors)
self.append(value)
dispatch[BINSTRING[0]] = load_binstring
def load_binbytes(self, unpack=struct.unpack, maxsize=sys.maxsize):
len, = unpack('<I', self.read(4))
if len > maxsize:
raise UnpicklingError("BINBYTES exceeds system's maximum size of %d bytes" % maxsize);
self.append(self.read(len))
dispatch[BINBYTES[0]] = load_binbytes
def load_unicode(self):
self.append(str(self.readline()[:-1], 'raw-unicode-escape'))
dispatch[UNICODE[0]] = load_unicode
def load_binunicode(self, unpack=struct.unpack, maxsize=sys.maxsize):
len, = unpack('<I', self.read(4))
if len > maxsize:
raise UnpicklingError("BINUNICODE exceeds system's maximum size of %d bytes" % maxsize);
self.append(str(self.read(len), 'utf-8', 'surrogatepass'))
dispatch[BINUNICODE[0]] = load_binunicode
def load_short_binstring(self):
len = ord(self.read(1))
data = bytes(self.read(len))
value = str(data, self.encoding, self.errors)
self.append(value)
dispatch[SHORT_BINSTRING[0]] = load_short_binstring
def load_short_binbytes(self):
len = ord(self.read(1))
self.append(bytes(self.read(len)))
dispatch[SHORT_BINBYTES[0]] = load_short_binbytes
def load_tuple(self):
k = self.marker()
self.stack[k:] = [tuple(self.stack[k+1:])]
dispatch[TUPLE[0]] = load_tuple
def load_empty_tuple(self):
self.append(())
dispatch[EMPTY_TUPLE[0]] = load_empty_tuple
def load_tuple1(self):
self.stack[-1] = (self.stack[-1],)
dispatch[TUPLE1[0]] = load_tuple1
def load_tuple2(self):
self.stack[-2:] = [(self.stack[-2], self.stack[-1])]
dispatch[TUPLE2[0]] = load_tuple2
def load_tuple3(self):
self.stack[-3:] = [(self.stack[-3], self.stack[-2], self.stack[-1])]
dispatch[TUPLE3[0]] = load_tuple3
def load_empty_list(self):
self.append([])
dispatch[EMPTY_LIST[0]] = load_empty_list
def load_empty_dictionary(self):
self.append({})
dispatch[EMPTY_DICT[0]] = load_empty_dictionary
def load_list(self):
k = self.marker()
self.stack[k:] = [self.stack[k+1:]]
dispatch[LIST[0]] = 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[0]] = load_dict
# INST and OBJ differ only in how they get a class object. It's not
# only sensible to do the rest in a common routine, the two routines
# previously diverged and grew different bugs.
# klass is the class to instantiate, and k points to the topmost mark
# object, following which are the arguments for klass.__init__.
def _instantiate(self, klass, k):
args = tuple(self.stack[k+1:])
del self.stack[k:]
if (args or not isinstance(klass, type) or
hasattr(klass, "__getinitargs__")):
try:
value = klass(*args)
except TypeError as err:
raise TypeError("in constructor for %s: %s" %
(klass.__name__, str(err)), sys.exc_info()[2])
else:
value = klass.__new__(klass)
self.append(value)
def load_inst(self):
module = self.readline()[:-1].decode("ascii")
name = self.readline()[:-1].decode("ascii")
klass = self.find_class(module, name)
self._instantiate(klass, self.marker())
dispatch[INST[0]] = load_inst
def load_obj(self):
# Stack is ... markobject classobject arg1 arg2 ...
k = self.marker()
klass = self.stack.pop(k+1)
self._instantiate(klass, k)
dispatch[OBJ[0]] = load_obj
def load_newobj(self):
args = self.stack.pop()
cls = self.stack[-1]
obj = cls.__new__(cls, *args)
self.stack[-1] = obj
dispatch[NEWOBJ[0]] = load_newobj
def load_global(self):
module = self.readline()[:-1].decode("utf-8")
name = self.readline()[:-1].decode("utf-8")
klass = self.find_class(module, name)
self.append(klass)
dispatch[GLOBAL[0]] = load_global
def load_ext1(self):
code = ord(self.read(1))
self.get_extension(code)
dispatch[EXT1[0]] = load_ext1
def load_ext2(self):
code = mloads(b'i' + self.read(2) + b'\000\000')
self.get_extension(code)
dispatch[EXT2[0]] = load_ext2
def load_ext4(self):
code = mloads(b'i' + self.read(4))
self.get_extension(code)
dispatch[EXT4[0]] = load_ext4
def get_extension(self, code):
nil = []
obj = _extension_cache.get(code, nil)
if obj is not nil:
self.append(obj)
return
key = _inverted_registry.get(code)
if not key:
if code <= 0: # note that 0 is forbidden
# Corrupt or hostile pickle.
raise UnpicklingError("EXT specifies code <= 0");
raise ValueError("unregistered extension code %d" % code)
obj = self.find_class(*key)
_extension_cache[code] = obj
self.append(obj)
def find_class(self, module, name):
# Subclasses may override this.
if self.proto < 3 and self.fix_imports:
if (module, name) in _compat_pickle.NAME_MAPPING:
module, name = _compat_pickle.NAME_MAPPING[(module, name)]
if module in _compat_pickle.IMPORT_MAPPING:
module = _compat_pickle.IMPORT_MAPPING[module]
__import__(module, level=0)
mod = sys.modules[module]
klass = getattr(mod, name)
return klass
def load_reduce(self):
stack = self.stack
args = stack.pop()
func = stack[-1]
try:
value = func(*args)
except:
print(sys.exc_info())
print(func, args)
raise
stack[-1] = value
dispatch[REDUCE[0]] = load_reduce
def load_pop(self):
del self.stack[-1]
dispatch[POP[0]] = load_pop
def load_pop_mark(self):
k = self.marker()
del self.stack[k:]
dispatch[POP_MARK[0]] = load_pop_mark
def load_dup(self):
self.append(self.stack[-1])
dispatch[DUP[0]] = load_dup
def load_get(self):
i = int(self.readline()[:-1])
self.append(self.memo[i])
dispatch[GET[0]] = load_get
def load_binget(self):
i = self.read(1)[0]
self.append(self.memo[i])
dispatch[BINGET[0]] = load_binget
def load_long_binget(self, unpack=struct.unpack):
i, = unpack('<I', self.read(4))
self.append(self.memo[i])
dispatch[LONG_BINGET[0]] = load_long_binget
def load_put(self):
i = int(self.readline()[:-1])
if i < 0:
raise ValueError("negative PUT argument")
self.memo[i] = self.stack[-1]
dispatch[PUT[0]] = load_put
def load_binput(self):
i = self.read(1)[0]
if i < 0:
raise ValueError("negative BINPUT argument")
self.memo[i] = self.stack[-1]
dispatch[BINPUT[0]] = load_binput
def load_long_binput(self, unpack=struct.unpack, maxsize=sys.maxsize):
i, = unpack('<I', self.read(4))
if i > maxsize:
raise ValueError("negative LONG_BINPUT argument")
self.memo[i] = self.stack[-1]
dispatch[LONG_BINPUT[0]] = load_long_binput
def load_append(self):
stack = self.stack
value = stack.pop()
list = stack[-1]
list.append(value)
dispatch[APPEND[0]] = 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[0]] = load_appends
def load_setitem(self):
stack = self.stack
value = stack.pop()
key = stack.pop()
dict = stack[-1]
dict[key] = value
dispatch[SETITEM[0]] = 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[0]] = load_setitems
def load_build(self):
stack = self.stack
state = stack.pop()
inst = stack[-1]
setstate = getattr(inst, "__setstate__", None)
if setstate:
setstate(state)
return
slotstate = None
if isinstance(state, tuple) and len(state) == 2:
state, slotstate = state
if state:
inst_dict = inst.__dict__
intern = sys.intern
for k, v in state.items():
if type(k) is str:
inst_dict[intern(k)] = v
else:
inst_dict[k] = v
if slotstate:
for k, v in slotstate.items():
setattr(inst, k, v)
dispatch[BUILD[0]] = load_build
def load_mark(self):
self.append(self.mark)
dispatch[MARK[0]] = load_mark
def load_stop(self):
value = self.stack.pop()
raise _Stop(value)
dispatch[STOP[0]] = load_stop
# Encode/decode longs.
def encode_long(x):
r"""Encode a long to a two's complement little-endian binary string.
Note that 0 is a special case, returning an empty string, to save a
byte in the LONG1 pickling context.
>>> encode_long(0)
b''
>>> encode_long(255)
b'\xff\x00'
>>> encode_long(32767)
b'\xff\x7f'
>>> encode_long(-256)
b'\x00\xff'
>>> encode_long(-32768)
b'\x00\x80'
>>> encode_long(-128)
b'\x80'
>>> encode_long(127)
b'\x7f'
>>>
"""
if x == 0:
return b''
nbytes = (x.bit_length() >> 3) + 1
result = x.to_bytes(nbytes, byteorder='little', signed=True)
if x < 0 and nbytes > 1:
if result[-1] == 0xff and (result[-2] & 0x80) != 0:
result = result[:-1]
return result
def decode_long(data):
r"""Decode a long from a two's complement little-endian binary string.
>>> decode_long(b'')
0
>>> decode_long(b"\xff\x00")
255
>>> decode_long(b"\xff\x7f")
32767
>>> decode_long(b"\x00\xff")
-256
>>> decode_long(b"\x00\x80")
-32768
>>> decode_long(b"\x80")
-128
>>> decode_long(b"\x7f")
127
"""
return int.from_bytes(data, byteorder='little', signed=True)
# Shorthands
def dump(obj, file, protocol=None, *, fix_imports=True):
Pickler(file, protocol, fix_imports=fix_imports).dump(obj)
def dumps(obj, protocol=None, *, fix_imports=True):
f = io.BytesIO()
Pickler(f, protocol, fix_imports=fix_imports).dump(obj)
res = f.getvalue()
assert isinstance(res, bytes_types)
return res
def load(file, *, fix_imports=True, encoding="ASCII", errors="strict"):
return Unpickler(file, fix_imports=fix_imports,
encoding=encoding, errors=errors).load()
def loads(s, *, fix_imports=True, encoding="ASCII", errors="strict"):
if isinstance(s, str):
raise TypeError("Can't load pickle from unicode string")
file = io.BytesIO(s)
return Unpickler(file, fix_imports=fix_imports,
encoding=encoding, errors=errors).load()
# Use the faster _pickle if possible
try:
from _pickle import *
except ImportError:
Pickler, Unpickler = _Pickler, _Unpickler
# Doctest
def _test():
import doctest
return doctest.testmod()
if __name__ == "__main__":
import argparse
parser = argparse.ArgumentParser(
description='display contents of the pickle files')
parser.add_argument(
'pickle_file', type=argparse.FileType('br'),
nargs='*', help='the pickle file')
parser.add_argument(
'-t', '--test', action='store_true',
help='run self-test suite')
parser.add_argument(
'-v', action='store_true',
help='run verbosely; only affects self-test run')
args = parser.parse_args()
if args.test:
_test()
else:
if not args.pickle_file:
parser.print_help()
else:
import pprint
for f in args.pickle_file:
obj = load(f)
pprint.pprint(obj)
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