"""
My own variation on function-specific inspect-like features.
"""
# Author: Gael Varoquaux <gael dot varoquaux at normalesup dot org>
# Copyright (c) 2009 Gael Varoquaux
# License: BSD Style, 3 clauses.
from __future__ import with_statement
from itertools import islice
import inspect
import warnings
import os
def get_func_code(func):
""" Attempts to retrieve a reliable function code hash.
The reason we don't use inspect.getsource is that it caches the
source, whereas we want this to be modified on the fly when the
function is modified.
Returns
-------
func_code: string
The function code
source_file: string
The path to the file in which the function is defined.
first_line: int
The first line of the code in the source file.
Notes
------
This function does a bit more magic than inspect, and is thus
more robust.
"""
source_file = None
try:
# Try to retrieve the source code.
source_file = func.func_code.co_filename
with open(source_file) as source_file_obj:
first_line = func.func_code.co_firstlineno
# All the lines after the function definition:
source_lines = list(islice(source_file_obj, first_line - 1, None))
return ''.join(inspect.getblock(source_lines)), source_file, first_line
except:
# If the source code fails, we use the hash. This is fragile and
# might change from one session to another.
if hasattr(func, 'func_code'):
return str(func.func_code.__hash__()), source_file, -1
else:
# Weird objects like numpy ufunc don't have func_code
# This is fragile, as quite often the id of the object is
# in the repr, so it might not persist accross sessions,
# however it will work for ufuncs.
return repr(func), source_file, -1
def _clean_win_chars(string):
"Windows cannot encode some characters in filenames"
import urllib
for char in ('<', '>', '!', ':', '\\'):
string = string.replace(char, urllib.quote(char))
return string
def get_func_name(func, resolv_alias=True, win_characters=True):
""" Return the function import path (as a list of module names), and
a name for the function.
Parameters
----------
func: callable
The func to inspect
resolv_alias: boolean, optional
If true, possible local aliases are indicated.
win_characters: boolean, optional
If true, substitute special characters using urllib.quote
This is useful in Windows, as it cannot encode some filenames
"""
if hasattr(func, '__module__'):
module = func.__module__
else:
try:
module = inspect.getmodule(func)
except TypeError:
if hasattr(func, '__class__'):
module = func.__class__.__module__
else:
module = 'unknown'
if module is None:
# Happens in doctests, eg
module = ''
if module == '__main__':
try:
filename = os.path.abspath(inspect.getsourcefile(func))
except:
filename = None
if filename is not None:
# mangling of full path to filename
filename = filename.replace(os.sep, '-')
filename = filename.replace(":", "-")
if filename.endswith('.py'):
filename = filename[:-3]
module = module + '-' + filename
module = module.split('.')
if hasattr(func, 'func_name'):
name = func.func_name
elif hasattr(func, '__name__'):
name = func.__name__
else:
name = 'unknown'
# Hack to detect functions not defined at the module-level
if resolv_alias:
# TODO: Maybe add a warning here?
if hasattr(func, 'func_globals') and name in func.func_globals:
if not func.func_globals[name] is func:
name = '%s-alias' % name
if inspect.ismethod(func):
# We need to add the name of the class
if hasattr(func, 'im_class'):
klass = func.im_class
module.append(klass.__name__)
if os.name == 'nt' and win_characters:
# Stupid windows can't encode certain characters in filenames
name = _clean_win_chars(name)
module = [_clean_win_chars(s) for s in module]
return module, name
def filter_args(func, ignore_lst, args=(), kwargs=dict()):
""" Filters the given args and kwargs using a list of arguments to
ignore, and a function specification.
Parameters
----------
func: callable
Function giving the argument specification
ignore_lst: list of strings
List of arguments to ignore (either a name of an argument
in the function spec, or '*', or '**')
*args: list
Positional arguments passed to the function.
**kwargs: dict
Keyword arguments passed to the function
Returns
-------
filtered_args: list
List of filtered positional arguments.
filtered_kwdargs: dict
List of filtered Keyword arguments.
"""
args = list(args)
if isinstance(ignore_lst, basestring):
# Catch a common mistake
raise ValueError('ignore_lst must be a list of parameters to ignore '
'%s (type %s) was given' % (ignore_lst, type(ignore_lst)))
# Special case for functools.partial objects
if (not inspect.ismethod(func) and not inspect.isfunction(func)):
if ignore_lst:
warnings.warn('Cannot inspect object %s, ignore list will '
'not work.' % func, stacklevel=2)
return {'*': args, '**': kwargs}
arg_spec = inspect.getargspec(func)
# We need to if/them to account for different versions of Python
if hasattr(arg_spec, 'args'):
arg_names = arg_spec.args
arg_defaults = arg_spec.defaults
arg_keywords = arg_spec.keywords
arg_varargs = arg_spec.varargs
else:
arg_names, arg_varargs, arg_keywords, arg_defaults = arg_spec
arg_defaults = arg_defaults or {}
if inspect.ismethod(func):
# First argument is 'self', it has been removed by Python
# we need to add it back:
args = [func.im_self, ] + args
# XXX: Maybe I need an inspect.isbuiltin to detect C-level methods, such
# as on ndarrays.
_, name = get_func_name(func, resolv_alias=False)
arg_dict = dict()
arg_position = -1
for arg_position, arg_name in enumerate(arg_names):
if arg_position < len(args):
# Positional argument or keyword argument given as positional
arg_dict[arg_name] = args[arg_position]
else:
position = arg_position - len(arg_names)
if arg_name in kwargs:
arg_dict[arg_name] = kwargs.pop(arg_name)
else:
try:
arg_dict[arg_name] = arg_defaults[position]
except (IndexError, KeyError):
# Missing argument
raise ValueError('Wrong number of arguments for %s%s:\n'
' %s(%s, %s) was called.'
% (name,
inspect.formatargspec(*inspect.getargspec(func)),
name,
repr(args)[1:-1],
', '.join('%s=%s' % (k, v)
for k, v in kwargs.iteritems())
)
)
varkwargs = dict()
for arg_name, arg_value in sorted(kwargs.items()):
if arg_name in arg_dict:
arg_dict[arg_name] = arg_value
elif arg_keywords is not None:
varkwargs[arg_name] = arg_value
else:
raise TypeError("Ignore list for %s() contains an unexpected "
"keyword argument '%s'" % (name, arg_name))
if arg_keywords is not None:
arg_dict['**'] = varkwargs
if arg_varargs is not None:
varargs = args[arg_position + 1:]
arg_dict['*'] = varargs
# Now remove the arguments to be ignored
for item in ignore_lst:
if item in arg_dict:
arg_dict.pop(item)
else:
raise ValueError("Ignore list: argument '%s' is not defined for "
"function %s%s" %
(item, name,
inspect.formatargspec(arg_names,
arg_varargs,
arg_keywords,
arg_defaults,
)))
# XXX: Return a sorted list of pairs?
return arg_dict