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pickle.py
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1962 lines (1702 loc) · 69.5 KB
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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(bytes) -> object
Misc variables:
format_version
compatible_formats
"""
from types import FunctionType
from copyreg import dispatch_table
from copyreg import _extension_registry, _inverted_registry, _extension_cache
from itertools import batched
from functools import partial
import sys
from sys import maxsize
from struct import pack, unpack
import io
import codecs
import _compat_pickle
__all__ = ["PickleError", "PicklingError", "UnpicklingError", "Pickler",
"Unpickler", "dump", "dumps", "load", "loads"]
try:
from _pickle import PickleBuffer
__all__.append("PickleBuffer")
_HAVE_PICKLE_BUFFER = True
except ImportError:
_HAVE_PICKLE_BUFFER = False
# Shortcut for use in isinstance testing
bytes_types = (bytes, bytearray)
# These are purely informational; no code uses these.
format_version = "5.0" # 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
"4.0", # Protocol 4
"5.0", # Protocol 5
] # Old format versions we can read
# This is the highest protocol number we know how to read.
HIGHEST_PROTOCOL = 5
# The protocol we write by default. May be less than HIGHEST_PROTOCOL.
# Only bump this if the oldest still supported version of Python already
# includes it.
DEFAULT_PROTOCOL = 5
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
# 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
# Protocol 4
SHORT_BINUNICODE = b'\x8c' # push short string; UTF-8 length < 256 bytes
BINUNICODE8 = b'\x8d' # push very long string
BINBYTES8 = b'\x8e' # push very long bytes string
EMPTY_SET = b'\x8f' # push empty set on the stack
ADDITEMS = b'\x90' # modify set by adding topmost stack items
FROZENSET = b'\x91' # build frozenset from topmost stack items
NEWOBJ_EX = b'\x92' # like NEWOBJ but work with keyword only arguments
STACK_GLOBAL = b'\x93' # same as GLOBAL but using names on the stacks
MEMOIZE = b'\x94' # store top of the stack in memo
FRAME = b'\x95' # indicate the beginning of a new frame
# Protocol 5
BYTEARRAY8 = b'\x96' # push bytearray
NEXT_BUFFER = b'\x97' # push next out-of-band buffer
READONLY_BUFFER = b'\x98' # make top of stack readonly
__all__.extend(x for x in dir() if x.isupper() and not x.startswith('_'))
# Data larger than this will be read in chunks, to prevent extreme
# overallocation.
_MIN_READ_BUF_SIZE = (1 << 20)
class _Framer:
_FRAME_SIZE_MIN = 4
_FRAME_SIZE_TARGET = 64 * 1024
def __init__(self, file_write):
self.file_write = file_write
self.current_frame = None
def start_framing(self):
self.current_frame = io.BytesIO()
def end_framing(self):
if self.current_frame and self.current_frame.tell() > 0:
self.commit_frame(force=True)
self.current_frame = None
def commit_frame(self, force=False):
if self.current_frame:
f = self.current_frame
if f.tell() >= self._FRAME_SIZE_TARGET or force:
data = f.getbuffer()
write = self.file_write
if len(data) >= self._FRAME_SIZE_MIN:
# Issue a single call to the write method of the underlying
# file object for the frame opcode with the size of the
# frame. The concatenation is expected to be less expensive
# than issuing an additional call to write.
write(FRAME + pack("<Q", len(data)))
# Issue a separate call to write to append the frame
# contents without concatenation to the above to avoid a
# memory copy.
write(data)
# Start the new frame with a new io.BytesIO instance so that
# the file object can have delayed access to the previous frame
# contents via an unreleased memoryview of the previous
# io.BytesIO instance.
self.current_frame = io.BytesIO()
def write(self, data):
if self.current_frame:
return self.current_frame.write(data)
else:
return self.file_write(data)
def write_large_bytes(self, header, payload):
write = self.file_write
if self.current_frame:
# Terminate the current frame and flush it to the file.
self.commit_frame(force=True)
# Perform direct write of the header and payload of the large binary
# object. Be careful not to concatenate the header and the payload
# prior to calling 'write' as we do not want to allocate a large
# temporary bytes object.
# We intentionally do not insert a protocol 4 frame opcode to make
# it possible to optimize file.read calls in the loader.
write(header)
write(payload)
class _Unframer:
def __init__(self, file_read, file_readline, file_tell=None):
self.file_read = file_read
self.file_readline = file_readline
self.current_frame = None
def readinto(self, buf):
if self.current_frame:
n = self.current_frame.readinto(buf)
if n == 0 and len(buf) != 0:
self.current_frame = None
n = len(buf)
buf[:] = self.file_read(n)
return n
if n < len(buf):
raise UnpicklingError(
"pickle exhausted before end of frame")
return n
else:
n = len(buf)
buf[:] = self.file_read(n)
return n
def read(self, n):
if self.current_frame:
data = self.current_frame.read(n)
if not data and n != 0:
self.current_frame = None
return self.file_read(n)
if len(data) < n:
raise UnpicklingError(
"pickle exhausted before end of frame")
return data
else:
return self._chunked_file_read(n)
def readline(self):
if self.current_frame:
data = self.current_frame.readline()
if not data:
self.current_frame = None
return self.file_readline()
if data[-1] != b'\n'[0]:
raise UnpicklingError(
"pickle exhausted before end of frame")
return data
else:
return self.file_readline()
def _chunked_file_read(self, size):
cursize = min(size, _MIN_READ_BUF_SIZE)
b = self.file_read(cursize)
while cursize < size and len(b) == cursize:
delta = min(cursize, size - cursize)
b += self.file_read(delta)
cursize += delta
return b
def load_frame(self, frame_size):
if self.current_frame and self.current_frame.read() != b'':
raise UnpicklingError(
"beginning of a new frame before end of current frame")
data = self._chunked_file_read(frame_size)
if len(data) < frame_size:
raise EOFError
self.current_frame = io.BytesIO(data)
# Tools used for pickling.
def _getattribute(obj, dotted_path):
for subpath in dotted_path:
obj = getattr(obj, subpath)
return obj
def whichmodule(obj, name):
"""Find the module an object belong to."""
dotted_path = name.split('.')
module_name = getattr(obj, '__module__', None)
if '<locals>' in dotted_path:
raise PicklingError(f"Can't pickle local object {obj!r}")
if module_name is None:
# Protect the iteration by using a list copy of sys.modules against dynamic
# modules that trigger imports of other modules upon calls to getattr.
for module_name, module in sys.modules.copy().items():
if (module_name == '__main__'
or module_name == '__mp_main__' # bpo-42406
or module is None):
continue
try:
if _getattribute(module, dotted_path) is obj:
return module_name
except AttributeError:
pass
module_name = '__main__'
try:
__import__(module_name, level=0)
module = sys.modules[module_name]
except (ImportError, ValueError, KeyError) as exc:
raise PicklingError(f"Can't pickle {obj!r}: {exc!s}")
try:
if _getattribute(module, dotted_path) is obj:
return module_name
except AttributeError:
raise PicklingError(f"Can't pickle {obj!r}: "
f"it's not found as {module_name}.{name}")
raise PicklingError(
f"Can't pickle {obj!r}: it's not the same object as {module_name}.{name}")
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)
def _T(obj):
cls = type(obj)
module = cls.__module__
if module in (None, 'builtins', '__main__'):
return cls.__qualname__
return f'{module}.{cls.__qualname__}'
_NoValue = object()
# Pickling machinery
class _Pickler:
def __init__(self, file, protocol=None, *, fix_imports=True,
buffer_callback=None):
"""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, 4 and 5.
The default protocol is 5. It was introduced in Python 3.8, and
is incompatible with previous versions.
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, an 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 names to the old module names
used in Python 2, so that the pickle data stream is readable
with Python 2.
If *buffer_callback* is None (the default), buffer views are
serialized into *file* as part of the pickle stream.
If *buffer_callback* is not None, then it can be called any number
of times with a buffer view. If the callback returns a false value
(such as None), the given buffer is out-of-band; otherwise the
buffer is serialized in-band, i.e. inside the pickle stream.
It is an error if *buffer_callback* is not None and *protocol*
is None or smaller than 5.
"""
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)
if buffer_callback is not None and protocol < 5:
raise ValueError("buffer_callback needs protocol >= 5")
self._buffer_callback = buffer_callback
try:
self._file_write = file.write
except AttributeError:
raise TypeError("file must have a 'write' attribute")
self.framer = _Framer(self._file_write)
self.write = self.framer.write
self._write_large_bytes = self.framer.write_large_bytes
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, "_file_write"):
raise PicklingError("Pickler.__init__() was not called by "
"%s.__init__()" % (self.__class__.__name__,))
if self.proto >= 2:
self.write(PROTO + pack("<B", self.proto))
if self.proto >= 4:
self.framer.start_framing()
self.save(obj)
self.write(STOP)
self.framer.end_framing()
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
idx = len(self.memo)
self.write(self.put(idx))
self.memo[id(obj)] = idx, obj
# Return a PUT (BINPUT, LONG_BINPUT) opcode string, with argument i.
def put(self, idx):
if self.proto >= 4:
return MEMOIZE
elif self.bin:
if idx < 256:
return BINPUT + pack("<B", idx)
else:
return LONG_BINPUT + pack("<I", idx)
else:
return PUT + repr(idx).encode("ascii") + b'\n'
# Return a GET (BINGET, LONG_BINGET) opcode string, with argument i.
def get(self, i):
if self.bin:
if i < 256:
return BINGET + pack("<B", i)
else:
return LONG_BINGET + pack("<I", i)
return GET + repr(i).encode("ascii") + b'\n'
def save(self, obj, save_persistent_id=True):
self.framer.commit_frame()
# Check for persistent id (defined by a subclass)
if save_persistent_id:
pid = self.persistent_id(obj)
if pid is not None:
self.save_pers(pid)
return
# Check the memo
x = self.memo.get(id(obj))
if x is not None:
self.write(self.get(x[0]))
return
rv = NotImplemented
reduce = getattr(self, "reducer_override", _NoValue)
if reduce is not _NoValue:
rv = reduce(obj)
if rv is NotImplemented:
# Check the type dispatch table
t = type(obj)
f = self.dispatch.get(t)
if f is not None:
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, _NoValue)
if reduce is not _NoValue:
rv = reduce(obj)
else:
# Check for a class with a custom metaclass; treat as regular
# class
if issubclass(t, type):
self.save_global(obj)
return
# Check for a __reduce_ex__ method, fall back to __reduce__
reduce = getattr(obj, "__reduce_ex__", _NoValue)
if reduce is not _NoValue:
rv = reduce(self.proto)
else:
reduce = getattr(obj, "__reduce__", _NoValue)
if reduce is not _NoValue:
rv = reduce()
else:
raise PicklingError(f"Can't pickle {_T(t)} object")
# Check for string returned by reduce(), meaning "save as global"
if isinstance(rv, str):
self.save_global(obj, rv)
return
try:
# Assert that reduce() returned a tuple
if not isinstance(rv, tuple):
raise PicklingError(f'__reduce__ must return a string or tuple, not {_T(rv)}')
# Assert that it returned an appropriately sized tuple
l = len(rv)
if not (2 <= l <= 6):
raise PicklingError("tuple returned by __reduce__ "
"must contain 2 through 6 elements")
# Save the reduce() output and finally memoize the object
self.save_reduce(obj=obj, *rv)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} object')
raise
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:
try:
self.write(PERSID + str(pid).encode("ascii") + b'\n')
except UnicodeEncodeError:
raise PicklingError(
"persistent IDs in protocol 0 must be ASCII strings")
def save_reduce(self, func, args, state=None, listitems=None,
dictitems=None, state_setter=None, *, obj=None):
# This API is called by some subclasses
if not callable(func):
raise PicklingError(f"first item of the tuple returned by __reduce__ "
f"must be callable, not {_T(func)}")
if not isinstance(args, tuple):
raise PicklingError(f"second item of the tuple returned by __reduce__ "
f"must be a tuple, not {_T(args)}")
save = self.save
write = self.write
func_name = getattr(func, "__name__", "")
if self.proto >= 2 and func_name == "__newobj_ex__":
cls, args, kwargs = args
if not hasattr(cls, "__new__"):
raise PicklingError("first argument to __newobj_ex__() has no __new__")
if obj is not None and cls is not obj.__class__:
raise PicklingError(f"first argument to __newobj_ex__() "
f"must be {obj.__class__!r}, not {cls!r}")
if self.proto >= 4:
try:
save(cls)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} class')
raise
try:
save(args)
save(kwargs)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} __new__ arguments')
raise
write(NEWOBJ_EX)
else:
func = partial(cls.__new__, cls, *args, **kwargs)
try:
save(func)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} reconstructor')
raise
save(())
write(REDUCE)
elif self.proto >= 2 and func_name == "__newobj__":
# A __reduce__ implementation can direct protocol 2 or newer 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("first argument to __newobj__() has no __new__")
if obj is not None and cls is not obj.__class__:
raise PicklingError(f"first argument to __newobj__() "
f"must be {obj.__class__!r}, not {cls!r}")
args = args[1:]
try:
save(cls)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} class')
raise
try:
save(args)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} __new__ arguments')
raise
write(NEWOBJ)
else:
try:
save(func)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} reconstructor')
raise
try:
save(args)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} reconstructor arguments')
raise
write(REDUCE)
if obj is not None:
# If the object is already in the memo, this means it is
# recursive. In this case, throw away everything we put on the
# stack, and fetch the object back from the memo.
if id(obj) in self.memo:
write(POP + self.get(self.memo[id(obj)][0]))
else:
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, obj)
if dictitems is not None:
self._batch_setitems(dictitems, obj)
if state is not None:
if state_setter is None:
try:
save(state)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} state')
raise
write(BUILD)
else:
# If a state_setter is specified, call it instead of load_build
# to update obj's with its previous state.
# First, push state_setter and its tuple of expected arguments
# (obj, state) onto the stack.
try:
save(state_setter)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} state setter')
raise
save(obj) # simple BINGET opcode as obj is already memoized.
try:
save(state)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} state')
raise
write(TUPLE2)
# Trigger a state_setter(obj, state) function call.
write(REDUCE)
# The purpose of state_setter is to carry-out an
# inplace modification of obj. We do not care about what the
# method might return, so its output is eventually removed from
# the stack.
write(POP)
# 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_bool(self, obj):
if self.proto >= 2:
self.write(NEWTRUE if obj else NEWFALSE)
else:
self.write(TRUE if obj else FALSE)
dispatch[bool] = save_bool
def save_long(self, obj):
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 + pack("<B", obj))
return
if obj <= 0xffff:
self.write(BININT2 + pack("<H", obj))
return
# Next check for 4-byte signed ints:
if -0x80000000 <= obj <= 0x7fffffff:
self.write(BININT + pack("<i", obj))
return
if self.proto >= 2:
encoded = encode_long(obj)
n = len(encoded)
if n < 256:
self.write(LONG1 + pack("<B", n) + encoded)
else:
self.write(LONG4 + pack("<i", n) + encoded)
return
if -0x80000000 <= obj <= 0x7fffffff:
self.write(INT + repr(obj).encode("ascii") + b'\n')
else:
self.write(LONG + repr(obj).encode("ascii") + b'L\n')
dispatch[int] = save_long
def save_float(self, obj):
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_no_memo(self, obj):
# helper for writing bytes objects for protocol >= 3
# without memoizing them
assert self.proto >= 3
n = len(obj)
if n <= 0xff:
self.write(SHORT_BINBYTES + pack("<B", n) + obj)
elif n > 0xffffffff and self.proto >= 4:
self._write_large_bytes(BINBYTES8 + pack("<Q", n), obj)
elif n >= self.framer._FRAME_SIZE_TARGET:
self._write_large_bytes(BINBYTES + pack("<I", n), obj)
else:
self.write(BINBYTES + pack("<I", n) + obj)
def save_bytes(self, obj):
if self.proto < 3:
if not obj: # bytes object is empty
self.save_reduce(bytes, (), obj=obj)
else:
self.save_reduce(codecs.encode,
(str(obj, 'latin1'), 'latin1'), obj=obj)
return
self._save_bytes_no_memo(obj)
self.memoize(obj)
dispatch[bytes] = save_bytes
def _save_bytearray_no_memo(self, obj):
# helper for writing bytearray objects for protocol >= 5
# without memoizing them
assert self.proto >= 5
n = len(obj)
if n >= self.framer._FRAME_SIZE_TARGET:
self._write_large_bytes(BYTEARRAY8 + pack("<Q", n), obj)
else:
self.write(BYTEARRAY8 + pack("<Q", n) + obj)
def save_bytearray(self, obj):
if self.proto < 5:
if not obj: # bytearray is empty
self.save_reduce(bytearray, (), obj=obj)
else:
self.save_reduce(bytearray, (bytes(obj),), obj=obj)
return
self._save_bytearray_no_memo(obj)
self.memoize(obj)
dispatch[bytearray] = save_bytearray
if _HAVE_PICKLE_BUFFER:
def save_picklebuffer(self, obj):
if self.proto < 5:
raise PicklingError("PickleBuffer can only be pickled with "
"protocol >= 5")
with obj.raw() as m:
if not m.contiguous:
raise PicklingError("PickleBuffer can not be pickled when "
"pointing to a non-contiguous buffer")
in_band = True
if self._buffer_callback is not None:
in_band = bool(self._buffer_callback(obj))
if in_band:
# Write data in-band
# XXX The C implementation avoids a copy here
buf = m.tobytes()
in_memo = id(buf) in self.memo
if m.readonly:
if in_memo:
self._save_bytes_no_memo(buf)
else:
self.save_bytes(buf)
else:
if in_memo:
self._save_bytearray_no_memo(buf)
else:
self.save_bytearray(buf)
else:
# Write data out-of-band
self.write(NEXT_BUFFER)
if m.readonly:
self.write(READONLY_BUFFER)
dispatch[PickleBuffer] = save_picklebuffer
def save_str(self, obj):
if self.bin:
encoded = obj.encode('utf-8', 'surrogatepass')
n = len(encoded)
if n <= 0xff and self.proto >= 4:
self.write(SHORT_BINUNICODE + pack("<B", n) + encoded)
elif n > 0xffffffff and self.proto >= 4:
self._write_large_bytes(BINUNICODE8 + pack("<Q", n), encoded)
elif n >= self.framer._FRAME_SIZE_TARGET:
self._write_large_bytes(BINUNICODE + pack("<I", n), encoded)
else:
self.write(BINUNICODE + pack("<I", n) + encoded)
else:
# Escape what raw-unicode-escape doesn't, but memoize the original.
tmp = obj.replace("\\", "\\u005c")
tmp = tmp.replace("\0", "\\u0000")
tmp = tmp.replace("\n", "\\u000a")
tmp = tmp.replace("\r", "\\u000d")
tmp = tmp.replace("\x1a", "\\u001a") # EOF on DOS
self.write(UNICODE + tmp.encode('raw-unicode-escape') + b'\n')
self.memoize(obj)
dispatch[str] = save_str
def save_tuple(self, obj):
if not obj: # tuple is empty
if self.bin:
self.write(EMPTY_TUPLE)
else:
self.write(MARK + TUPLE)
return
n = len(obj)
save = self.save
memo = self.memo
if n <= 3 and self.proto >= 2:
for i, element in enumerate(obj):
try:
save(element)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} item {i}')
raise
# Subtle. Same as in the big comment below.
if id(obj) in memo:
get = self.get(memo[id(obj)][0])
self.write(POP * n + get)
else:
self.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 = self.write
write(MARK)
for i, element in enumerate(obj):
try:
save(element)
except BaseException as exc:
exc.add_note(f'when serializing {_T(obj)} item {i}')