pickletools —- Tools for pickle developers

Source code:Lib/pickletools.py

This module contains various constants relating to the intimate details of thepickle module, some lengthy comments about the implementation, and afew useful functions for analyzing pickled data. The contents of this moduleare useful for Python core developers who are working on the pickle;ordinary users of the pickle module probably won't find thepickletools module relevant.

命令行语法

3.2 新版功能.

When invoked from the command line, python -m pickletools willdisassemble the contents of one or more pickle files. Note that ifyou want to see the Python object stored in the pickle rather than thedetails of pickle format, you may want to use -m pickle instead.However, when the pickle file that you want to examine comes from anuntrusted source, -m pickletools is a safer option because it doesnot 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

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 betweendisassemblies.

• -p, —preamble=<preamble>

• When more than one pickle file are specified, print given preamblebefore each disassembly.

Programmatic Interface

• pickletools.dis(pickle, out=None, memo=None, indentlevel=4, annotate=0)
• Outputs a symbolic disassembly of the pickle to the file-likeobject out, defaulting to sys.stdout. pickle can be astring or a file-like object. memo can be a Python dictionarythat will be used as the pickle's memo; it can be used to performdisassemblies across multiple pickles created by the samepickler. Successive levels, indicated by MARK opcodes in thestream, are indented by indentlevel spaces. If a nonzero valueis given to annotate, each opcode in the output is annotated witha short description. The value of annotate is used as a hint forthe column where annotation should start.

3.2 新版功能: The annotate argument.

• pickletools.genops(pickle)

• Provides an iterator over all of the opcodes in a pickle, returning asequence of (opcode, arg, pos) triples. opcode is an instance of anOpcodeInfo class; arg is the decoded value, as a Python object, ofthe 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 PUTopcodes. The optimized pickle is shorter, takes less transmission time,requires less storage space, and unpickles more efficiently.