32.13. "pickletools" --- Tools for pickle developers
****************************************************

**Source code:** Lib/pickletools.py

======================================================================

This module contains various constants relating to the intimate
details of the "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 "pickle"; ordinary users of the "pickle" module
probably won't find the "pickletools" module relevant.


32.13.1. Command line usage
===========================

3.2 版新加入.

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":

   $ 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


32.13.1.1. Command line options
-------------------------------

-a, --annotate

   Annotate each line with a short opcode description.

-o, --output=<file>

   Name of a file where the output should be written.

-l, --indentlevel=<num>

   The number of blanks by which to indent a new MARK level.

-m, --memo

   When multiple objects are disassembled, preserve memo between
   disassemblies.

-p, --preamble=<preamble>

   When more than one pickle file are specified, print given preamble
   before each disassembly.


32.13.2. Programmatic Interface
===============================

pickletools.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.

   3.2 版新加入: The *annotate* argument.

pickletools.genops(pickle)

   Provides an *iterator* over all of the opcodes in a pickle,
   returning a sequence of "(opcode, arg, pos)" triples.  *opcode* is
   an instance of an "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.

pickletools.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.
