# Copyright 2016 Quora, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
__doc__ = """
Code inspection helpers.
"""
import functools
import inspect
import six
import sys
def get_original_fn(fn):
"""Gets the very original function of a decorated one."""
fn_type = type(fn)
if fn_type is classmethod or fn_type is staticmethod:
return get_original_fn(fn.__func__)
if hasattr(fn, "original_fn"):
return fn.original_fn
if hasattr(fn, "fn"):
fn.original_fn = get_original_fn(fn.fn)
return fn.original_fn
return fn
def get_full_name(src):
"""Gets full class or function name."""
if hasattr(src, "_full_name_"):
return src._full_name_
if hasattr(src, "is_decorator"):
# Our own decorator or binder
if hasattr(src, "decorator"):
# Our own binder
_full_name_ = str(src.decorator)
# It's a short-living object, so we don't cache result
else:
# Our own decorator
_full_name_ = str(src)
try:
src._full_name_ = _full_name_
except AttributeError:
pass
except TypeError:
pass
elif hasattr(src, "im_class"):
# Bound method
cls = src.im_class
_full_name_ = get_full_name(cls) + "." + src.__name__
# It's a short-living object, so we don't cache result
elif hasattr(src, "__module__") and hasattr(src, "__name__"):
# Func or class
_full_name_ = (
("<unknown module>" if src.__module__ is None else src.__module__)
+ "."
+ src.__name__
)
try:
src._full_name_ = _full_name_
except AttributeError:
pass
except TypeError:
pass
else:
# Something else
_full_name_ = str(get_original_fn(src))
return _full_name_
def get_function_call_str(fn, args, kwargs):
"""Converts method call (function and its arguments) to a str(...)-like string."""
def str_converter(v):
try:
return str(v)
except Exception:
try:
return repr(v)
except Exception:
return "<n/a str raised>"
result = get_full_name(fn) + "("
first = True
for v in args:
if first:
first = False
else:
result += ","
result += str_converter(v)
for k, v in kwargs.items():
if first:
first = False
else:
result += ","
result += str(k) + "=" + str_converter(v)
result += ")"
return result
def get_function_call_repr(fn, args, kwargs):
"""Converts method call (function and its arguments) to a repr(...)-like string."""
result = get_full_name(fn) + "("
first = True
for v in args:
if first:
first = False
else:
result += ","
result += repr(v)
for k, v in kwargs.items():
if first:
first = False
else:
result += ","
result += str(k) + "=" + repr(v)
result += ")"
return result
def getargspec(func):
"""Variation of inspect.getargspec that works for more functions.
This function works for Cythonized, non-cpdef functions, which expose argspec information but
are not accepted by getargspec. It also works for Python 3 functions that use annotations, which
are simply ignored. However, keyword-only arguments are not supported.
"""
if inspect.ismethod(func):
func = func.__func__
# Cythonized functions have a .__code__, but don't pass inspect.isfunction()
try:
code = func.__code__
except AttributeError:
raise TypeError("{!r} is not a Python function".format(func))
if hasattr(code, "co_kwonlyargcount") and code.co_kwonlyargcount > 0:
raise ValueError("keyword-only arguments are not supported by getargspec()")
args, varargs, varkw = inspect.getargs(code)
return inspect.ArgSpec(args, varargs, varkw, func.__defaults__)
def is_cython_or_generator(fn):
"""Returns whether this function is either a generator function or a Cythonized function."""
if hasattr(fn, "__func__"):
fn = fn.__func__ # Class method, static method
if inspect.isgeneratorfunction(fn):
return True
name = type(fn).__name__
return (
name == "generator"
or name == "method_descriptor"
or name == "cython_function_or_method"
or name == "builtin_function_or_method"
)
def is_cython_function(fn):
"""Checks if a function is compiled w/Cython."""
if hasattr(fn, "__func__"):
fn = fn.__func__ # Class method, static method
name = type(fn).__name__
return (
name == "method_descriptor"
or name == "cython_function_or_method"
or name == "builtin_function_or_method"
)
def is_cython_class(cls):
"""Returns whether a class is a Cython extension class."""
return "__pyx_vtable__" in cls.__dict__
def is_classmethod(fn):
"""Returns whether f is a classmethod."""
# This is True for bound methods
if not inspect.ismethod(fn):
return False
if not hasattr(fn, "__self__"):
return False
im_self = fn.__self__
# This is None for instance methods on classes, but True
# for instance methods on instances.
if im_self is None:
return False
# This is True for class methods of new- and old-style classes, respectively
return isinstance(im_self, six.class_types)
def wraps(
wrapped, assigned=functools.WRAPPER_ASSIGNMENTS, updated=functools.WRAPPER_UPDATES
):
"""Cython-compatible functools.wraps implementation."""
if not is_cython_function(wrapped):
return functools.wraps(wrapped, assigned, updated)
else:
return lambda wrapper: wrapper
def get_subclass_tree(cls, ensure_unique=True):
"""Returns all subclasses (direct and recursive) of cls."""
subclasses = []
# cls.__subclasses__() fails on classes inheriting from type
for subcls in type.__subclasses__(cls):
subclasses.append(subcls)
subclasses.extend(get_subclass_tree(subcls, ensure_unique))
return list(set(subclasses)) if ensure_unique else subclasses
def lazy_stack():
"""Return a generator of records for the stack above the caller's frame.
Equivalent to inspect.stack() but potentially faster because it does not compute info for all
stack frames.
As a further optimization, yields raw frame objects instead of tuples describing the frame. To
get the full information, call inspect.getframeinfo(frame).
"""
frame = sys._getframe(1)
while frame:
yield frame
frame = frame.f_back
