You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
111 lines
3.6 KiB
111 lines
3.6 KiB
:mod:`pickletools` --- Tools for pickle developers
|
|
==================================================
|
|
|
|
.. module:: pickletools
|
|
:synopsis: Contains extensive comments about the pickle protocols and
|
|
pickle-machine opcodes, as well as some useful functions.
|
|
|
|
**Source code:** :source:`Lib/pickletools.py`
|
|
|
|
--------------
|
|
|
|
|
|
This module contains various constants relating to the intimate details of the
|
|
:mod:`pickle` module, some lengthy comments about the implementation, and a
|
|
few useful functions for analyzing pickled data. The contents of this module
|
|
are useful for Python core developers who are working on the :mod:`pickle`;
|
|
ordinary users of the :mod:`pickle` module probably won't find the
|
|
:mod:`pickletools` module relevant.
|
|
|
|
Command line usage
|
|
------------------
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
When invoked from the command line, ``python -m pickletools`` will
|
|
disassemble the contents of one or more pickle files. Note that if
|
|
you want to see the Python object stored in the pickle rather than the
|
|
details of pickle format, you may want to use ``-m pickle`` instead.
|
|
However, when the pickle file that you want to examine comes from an
|
|
untrusted source, ``-m pickletools`` is a safer option because it does
|
|
not execute pickle bytecode.
|
|
|
|
For example, with a tuple ``(1, 2)`` pickled in file ``x.pickle``:
|
|
|
|
.. code-block:: shell-session
|
|
|
|
$ python -m pickle x.pickle
|
|
(1, 2)
|
|
|
|
$ python -m pickletools x.pickle
|
|
0: \x80 PROTO 3
|
|
2: K BININT1 1
|
|
4: K BININT1 2
|
|
6: \x86 TUPLE2
|
|
7: q BINPUT 0
|
|
9: . STOP
|
|
highest protocol among opcodes = 2
|
|
|
|
Command line options
|
|
^^^^^^^^^^^^^^^^^^^^
|
|
|
|
.. program:: pickletools
|
|
|
|
.. cmdoption:: -a, --annotate
|
|
|
|
Annotate each line with a short opcode description.
|
|
|
|
.. cmdoption:: -o, --output=<file>
|
|
|
|
Name of a file where the output should be written.
|
|
|
|
.. cmdoption:: -l, --indentlevel=<num>
|
|
|
|
The number of blanks by which to indent a new MARK level.
|
|
|
|
.. cmdoption:: -m, --memo
|
|
|
|
When multiple objects are disassembled, preserve memo between
|
|
disassemblies.
|
|
|
|
.. cmdoption:: -p, --preamble=<preamble>
|
|
|
|
When more than one pickle file are specified, print given preamble
|
|
before each disassembly.
|
|
|
|
|
|
|
|
Programmatic Interface
|
|
----------------------
|
|
|
|
|
|
.. function:: dis(pickle, out=None, memo=None, indentlevel=4, annotate=0)
|
|
|
|
Outputs a symbolic disassembly of the pickle to the file-like
|
|
object *out*, defaulting to ``sys.stdout``. *pickle* can be a
|
|
string or a file-like object. *memo* can be a Python dictionary
|
|
that will be used as the pickle's memo; it can be used to perform
|
|
disassemblies across multiple pickles created by the same
|
|
pickler. Successive levels, indicated by ``MARK`` opcodes in the
|
|
stream, are indented by *indentlevel* spaces. If a nonzero value
|
|
is given to *annotate*, each opcode in the output is annotated with
|
|
a short description. The value of *annotate* is used as a hint for
|
|
the column where annotation should start.
|
|
|
|
.. versionadded:: 3.2
|
|
The *annotate* argument.
|
|
|
|
.. function:: genops(pickle)
|
|
|
|
Provides an :term:`iterator` over all of the opcodes in a pickle, returning a
|
|
sequence of ``(opcode, arg, pos)`` triples. *opcode* is an instance of an
|
|
:class:`OpcodeInfo` class; *arg* is the decoded value, as a Python object, of
|
|
the opcode's argument; *pos* is the position at which this opcode is located.
|
|
*pickle* can be a string or a file-like object.
|
|
|
|
.. function:: optimize(picklestring)
|
|
|
|
Returns a new equivalent pickle string after eliminating unused ``PUT``
|
|
opcodes. The optimized pickle is shorter, takes less transmission time,
|
|
requires less storage space, and unpickles more efficiently.
|