bpython/bpython/inspection.py at master · ORG-MARS/bpython · GitHub

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# The MIT License

# Permission is hereby granted, free of charge, to any person obtaining a copy

# of this software and associated documentation files (the "Software"), to deal

# in the Software without restriction, including without limitation the rights

# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

# copies of the Software, and to permit persons to whom the Software is

# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in

# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

# THE SOFTWARE.

import inspect

import keyword

import pydoc

from collections import namedtuple

from pygments.token import Token

from pygments.lexers import Python3Lexer

from types import MemberDescriptorType

from .lazyre import LazyReCompile

ArgSpec = namedtuple(

"ArgSpec",

[

"args",

"varargs",

"varkwargs",

"defaults",

"kwonly",

"kwonly_defaults",

"annotations",

)

FuncProps = namedtuple("FuncProps", ["func", "argspec", "is_bound_method"])

class AttrCleaner:

"""A context manager that tries to make an object not exhibit side-effects

on attribute lookup."""

def __init__(self, obj):

self.obj = obj

def __enter__(self):

"""Try to make an object not exhibit side-effects on attribute

lookup."""

type_ = type(self.obj)

__getattribute__ = None

__getattr__ = None

# Dark magic:

# If __getattribute__ doesn't exist on the class and __getattr__ does

# then __getattr__ will be called when doing

# getattr(type_, '__getattribute__', None)

# so we need to first remove the __getattr__, then the

# __getattribute__, then look up the attributes and then restore the

# original methods. :-(

# The upshot being that introspecting on an object to display its

# attributes will avoid unwanted side-effects.

__getattr__ = getattr(type_, "__getattr__", None)

if __getattr__ is not None:

try:

setattr(type_, "__getattr__", (lambda *_, **__: None))

except TypeError:

__getattr__ = None

__getattribute__ = getattr(type_, "__getattribute__", None)

if __getattribute__ is not None:

try:

setattr(type_, "__getattribute__", object.__getattribute__)

except TypeError:

# XXX: This happens for e.g. built-in types

__getattribute__ = None

self.attribs = (__getattribute__, __getattr__)

# /Dark magic

def __exit__(self, exc_type, exc_val, exc_tb):

"""Restore an object's magic methods."""

type_ = type(self.obj)

__getattribute__, __getattr__ = self.attribs

# Dark magic:

if __getattribute__ is not None:

setattr(type_, "__getattribute__", __getattribute__)

if __getattr__ is not None:

setattr(type_, "__getattr__", __getattr__)

# /Dark magic

class _Repr:

"""

Helper for `fixlongargs()`: Returns the given value in `__repr__()`.

"""

def __init__(self, value):

self.value = value

def __repr__(self):

return self.value

__str__ = __repr__

def parsekeywordpairs(signature):

tokens = Python3Lexer().get_tokens(signature)

preamble = True

stack = []

substack = []

parendepth = 0

for token, value in tokens:

if preamble:

if token is Token.Punctuation and value == "(":

preamble = False

continue

if token is Token.Punctuation:

if value in ("(", "{", "["):

parendepth += 1

elif value in (")", "}", "]"):

parendepth -= 1

elif value == ":" and parendepth == -1:

# End of signature reached

break

if (value == "," and parendepth == 0) or (

value == ")" and parendepth == -1

stack.append(substack)

substack = []

continue

if value and (parendepth > 0 or value.strip()):

substack.append(value)

return {item[0]: "".join(item[2:]) for item in stack if len(item) >= 3}

def fixlongargs(f, argspec):

"""Functions taking default arguments that are references to other objects

whose str() is too big will cause breakage, so we swap out the object

itself with the name it was referenced with in the source by parsing the

source itself !"""

if argspec[3] is None:

# No keyword args, no need to do anything

return

values = list(argspec[3])

if not values:

return

keys = argspec[0][-len(values) :]

try:

src = inspect.getsourcelines(f)

except (OSError, IndexError):

# IndexError is raised in inspect.findsource(), can happen in

# some situations. See issue #94.

return

signature = "".join(src[0])

kwparsed = parsekeywordpairs(signature)

for i, (key, value) in enumerate(zip(keys, values)):

if len(repr(value)) != len(kwparsed[key]):

values[i] = _Repr(kwparsed[key])

argspec[3] = values

getpydocspec_re = LazyReCompile(r"([a-zA-Z_][a-zA-Z0-9_]*?)$(.*?)$")

def getpydocspec(f, func):

try:

argspec = pydoc.getdoc(f)

except NameError:

return None

s = getpydocspec_re.search(argspec)

if s is None:

return None

if not hasattr_safe(f, "__name__") or s.groups()[0] != f.__name__:

return None

args = list()

defaults = list()

varargs = varkwargs = None

kwonly_args = list()

kwonly_defaults = dict()

for arg in s.group(2).split(","):

arg = arg.strip()

if arg.startswith("**"):

varkwargs = arg[2:]

elif arg.startswith("*"):

varargs = arg[1:]

else:

arg, _, default = arg.partition("=")

if varargs is not None:

kwonly_args.append(arg)

if default:

kwonly_defaults[arg] = default

else:

args.append(arg)

if default:

defaults.append(default)

return ArgSpec(

args, varargs, varkwargs, defaults, kwonly_args, kwonly_defaults, None

)

def getfuncprops(func, f):

# Check if it's a real bound method or if it's implicitly calling __init__

# (i.e. FooClass(...) and not FooClass.__init__(...) -- the former would

# not take 'self', the latter would:

try:

func_name = getattr(f, "__name__", None)

except:

# if calling foo.__name__ would result in an error

func_name = None

try:

is_bound_method = (

(inspect.ismethod(f) and f.__self__ is not None)

or (func_name == "__init__" and not func.endswith(".__init__"))

or (func_name == "__new__" and not func.endswith(".__new__"))

)

except:

# if f is a method from a xmlrpclib.Server instance, func_name ==

# '__init__' throws xmlrpclib.Fault (see #202)

return None

try:

argspec = get_argspec_from_signature(f)

fixlongargs(f, argspec)

if len(argspec) == 4:

argspec = argspec + [list(), dict(), None]

argspec = ArgSpec(*argspec)

fprops = FuncProps(func, argspec, is_bound_method)

except (TypeError, KeyError, ValueError):

argspec = getpydocspec(f, func)

if argspec is None:

return None

if inspect.ismethoddescriptor(f):

argspec.args.insert(0, "obj")

fprops = FuncProps(func, argspec, is_bound_method)

return fprops

def is_eval_safe_name(string):

return all(

part.isidentifier() and not keyword.iskeyword(part)

for part in string.split(".")

)

def get_argspec_from_signature(f):

"""Get callable signature from inspect.signature in argspec format.

inspect.signature is a Python 3 only function that returns the signature of

a function. Its advantage over inspect.getfullargspec is that it returns

the signature of a decorated function, if the wrapper function itself is

decorated with functools.wraps.

"""

args = []

varargs = varkwargs = None

defaults = []

kwonly = []

kwonly_defaults = {}

annotations = {}

signature = inspect.signature(f)

for parameter in signature.parameters.values():

if parameter.annotation is not inspect._empty:

annotations[parameter.name] = parameter.annotation

if parameter.kind == inspect.Parameter.POSITIONAL_OR_KEYWORD:

args.append(parameter.name)

if parameter.default is not inspect._empty:

defaults.append(parameter.default)

elif parameter.kind == inspect.Parameter.POSITIONAL_ONLY:

args.append(parameter.name)

elif parameter.kind == inspect.Parameter.VAR_POSITIONAL:

varargs = parameter.name

elif parameter.kind == inspect.Parameter.KEYWORD_ONLY:

kwonly.append(parameter.name)

kwonly_defaults[parameter.name] = parameter.default

elif parameter.kind == inspect.Parameter.VAR_KEYWORD:

varkwargs = parameter.name

# inspect.getfullargspec returns None for 'defaults', 'kwonly_defaults' and

# 'annotations' if there are no values for them.

if not defaults:

defaults = None

if not kwonly_defaults:

kwonly_defaults = None

if not annotations:

annotations = None

return [

args,

varargs,

varkwargs,

defaults,

kwonly,

kwonly_defaults,

annotations,

]

get_encoding_line_re = LazyReCompile(r"^.*coding[:=]\s*([-\w.]+).*$")

def get_encoding(obj):

"""Try to obtain encoding information of the source of an object."""

for line in inspect.findsource(obj)[0][:2]:

m = get_encoding_line_re.search(line)

if m:

return m.group(1)

return "ascii"

def get_encoding_file(fname):

"""Try to obtain encoding information from a Python source file."""

with open(fname, encoding="ascii", errors="ignore") as f:

for unused in range(2):

line = f.readline()

match = get_encoding_line_re.search(line)

if match:

return match.group(1)

return "ascii"

def getattr_safe(obj, name):

"""side effect free getattr (calls getattr_static)."""

result = inspect.getattr_static(obj, name)

# Slots are a MemberDescriptorType

if isinstance(result, MemberDescriptorType):

result = getattr(obj, name)

return result

def hasattr_safe(obj, name):

try:

getattr_safe(obj, name)

return True

except AttributeError:

return False

def get_source_unicode(obj):

"""Returns a decoded source of object"""

return inspect.getsource(obj)

bpython/bpython/inspection.py at master · ORG-MARS/bpython · GitHub

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