Update 2025-04-24_11:44:19

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__version_info__ = ('1', '17', '2')
__version__ = '.'.join(__version_info__)
from .__wrapt__ import (ObjectProxy, CallableObjectProxy, FunctionWrapper,
BoundFunctionWrapper, PartialCallableObjectProxy)
from .patches import (resolve_path, apply_patch, wrap_object, wrap_object_attribute,
function_wrapper, wrap_function_wrapper, patch_function_wrapper,
transient_function_wrapper)
from .weakrefs import WeakFunctionProxy
from .decorators import (adapter_factory, AdapterFactory, decorator,
synchronized)
from .importer import (register_post_import_hook, when_imported,
notify_module_loaded, discover_post_import_hooks)
# Import of inspect.getcallargs() included for backward compatibility. An
# implementation of this was previously bundled and made available here for
# Python <2.7. Avoid using this in future.
from inspect import getcallargs
# Variant of inspect.formatargspec() included here for forward compatibility.
# This is being done because Python 3.11 dropped inspect.formatargspec() but
# code for handling signature changing decorators relied on it. Exposing the
# bundled implementation here in case any user of wrapt was also needing it.
from .arguments import formatargspec

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import os
from .wrappers import (ObjectProxy, CallableObjectProxy,
PartialCallableObjectProxy, FunctionWrapper,
BoundFunctionWrapper, _FunctionWrapperBase)
try:
if not os.environ.get('WRAPT_DISABLE_EXTENSIONS'):
from ._wrappers import (ObjectProxy, CallableObjectProxy,
PartialCallableObjectProxy, FunctionWrapper,
BoundFunctionWrapper, _FunctionWrapperBase)
except ImportError:
pass

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# The inspect.formatargspec() function was dropped in Python 3.11 but we need
# need it for when constructing signature changing decorators based on result of
# inspect.getargspec() or inspect.getfullargspec(). The code here implements
# inspect.formatargspec() base on Parameter and Signature from inspect module,
# which were added in Python 3.6. Thanks to Cyril Jouve for the implementation.
try:
from inspect import Parameter, Signature
except ImportError:
from inspect import formatargspec
else:
def formatargspec(args, varargs=None, varkw=None, defaults=None,
kwonlyargs=(), kwonlydefaults={}, annotations={}):
if kwonlydefaults is None:
kwonlydefaults = {}
ndefaults = len(defaults) if defaults else 0
parameters = [
Parameter(
arg,
Parameter.POSITIONAL_OR_KEYWORD,
default=defaults[i] if i >= 0 else Parameter.empty,
annotation=annotations.get(arg, Parameter.empty),
) for i, arg in enumerate(args, ndefaults - len(args))
]
if varargs:
parameters.append(Parameter(varargs, Parameter.VAR_POSITIONAL))
parameters.extend(
Parameter(
kwonlyarg,
Parameter.KEYWORD_ONLY,
default=kwonlydefaults.get(kwonlyarg, Parameter.empty),
annotation=annotations.get(kwonlyarg, Parameter.empty),
) for kwonlyarg in kwonlyargs
)
if varkw:
parameters.append(Parameter(varkw, Parameter.VAR_KEYWORD))
return_annotation = annotations.get('return', Signature.empty)
return str(Signature(parameters, return_annotation=return_annotation))

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"""This module implements decorators for implementing other decorators
as well as some commonly used decorators.
"""
import sys
PY2 = sys.version_info[0] == 2
if PY2:
string_types = basestring,
def exec_(_code_, _globs_=None, _locs_=None):
"""Execute code in a namespace."""
if _globs_ is None:
frame = sys._getframe(1)
_globs_ = frame.f_globals
if _locs_ is None:
_locs_ = frame.f_locals
del frame
elif _locs_ is None:
_locs_ = _globs_
exec("""exec _code_ in _globs_, _locs_""")
else:
string_types = str,
import builtins
exec_ = getattr(builtins, "exec")
del builtins
from functools import partial
from inspect import isclass
from threading import Lock, RLock
from .arguments import formatargspec
try:
from inspect import signature
except ImportError:
pass
from .__wrapt__ import (FunctionWrapper, BoundFunctionWrapper, ObjectProxy,
CallableObjectProxy)
# Adapter wrapper for the wrapped function which will overlay certain
# properties from the adapter function onto the wrapped function so that
# functions such as inspect.getargspec(), inspect.getfullargspec(),
# inspect.signature() and inspect.getsource() return the correct results
# one would expect.
class _AdapterFunctionCode(CallableObjectProxy):
def __init__(self, wrapped_code, adapter_code):
super(_AdapterFunctionCode, self).__init__(wrapped_code)
self._self_adapter_code = adapter_code
@property
def co_argcount(self):
return self._self_adapter_code.co_argcount
@property
def co_code(self):
return self._self_adapter_code.co_code
@property
def co_flags(self):
return self._self_adapter_code.co_flags
@property
def co_kwonlyargcount(self):
return self._self_adapter_code.co_kwonlyargcount
@property
def co_varnames(self):
return self._self_adapter_code.co_varnames
class _AdapterFunctionSurrogate(CallableObjectProxy):
def __init__(self, wrapped, adapter):
super(_AdapterFunctionSurrogate, self).__init__(wrapped)
self._self_adapter = adapter
@property
def __code__(self):
return _AdapterFunctionCode(self.__wrapped__.__code__,
self._self_adapter.__code__)
@property
def __defaults__(self):
return self._self_adapter.__defaults__
@property
def __kwdefaults__(self):
return self._self_adapter.__kwdefaults__
@property
def __signature__(self):
if 'signature' not in globals():
return self._self_adapter.__signature__
else:
return signature(self._self_adapter)
if PY2:
func_code = __code__
func_defaults = __defaults__
class _BoundAdapterWrapper(BoundFunctionWrapper):
@property
def __func__(self):
return _AdapterFunctionSurrogate(self.__wrapped__.__func__,
self._self_parent._self_adapter)
@property
def __signature__(self):
if 'signature' not in globals():
return self.__wrapped__.__signature__
else:
return signature(self._self_parent._self_adapter)
if PY2:
im_func = __func__
class AdapterWrapper(FunctionWrapper):
__bound_function_wrapper__ = _BoundAdapterWrapper
def __init__(self, *args, **kwargs):
adapter = kwargs.pop('adapter')
super(AdapterWrapper, self).__init__(*args, **kwargs)
self._self_surrogate = _AdapterFunctionSurrogate(
self.__wrapped__, adapter)
self._self_adapter = adapter
@property
def __code__(self):
return self._self_surrogate.__code__
@property
def __defaults__(self):
return self._self_surrogate.__defaults__
@property
def __kwdefaults__(self):
return self._self_surrogate.__kwdefaults__
if PY2:
func_code = __code__
func_defaults = __defaults__
@property
def __signature__(self):
return self._self_surrogate.__signature__
class AdapterFactory(object):
def __call__(self, wrapped):
raise NotImplementedError()
class DelegatedAdapterFactory(AdapterFactory):
def __init__(self, factory):
super(DelegatedAdapterFactory, self).__init__()
self.factory = factory
def __call__(self, wrapped):
return self.factory(wrapped)
adapter_factory = DelegatedAdapterFactory
# Decorator for creating other decorators. This decorator and the
# wrappers which they use are designed to properly preserve any name
# attributes, function signatures etc, in addition to the wrappers
# themselves acting like a transparent proxy for the original wrapped
# function so the wrapper is effectively indistinguishable from the
# original wrapped function.
def decorator(wrapper=None, enabled=None, adapter=None, proxy=FunctionWrapper):
# The decorator should be supplied with a single positional argument
# which is the wrapper function to be used to implement the
# decorator. This may be preceded by a step whereby the keyword
# arguments are supplied to customise the behaviour of the
# decorator. The 'adapter' argument is used to optionally denote a
# separate function which is notionally used by an adapter
# decorator. In that case parts of the function '__code__' and
# '__defaults__' attributes are used from the adapter function
# rather than those of the wrapped function. This allows for the
# argument specification from inspect.getfullargspec() and similar
# functions to be overridden with a prototype for a different
# function than what was wrapped. The 'enabled' argument provides a
# way to enable/disable the use of the decorator. If the type of
# 'enabled' is a boolean, then it is evaluated immediately and the
# wrapper not even applied if it is False. If not a boolean, it will
# be evaluated when the wrapper is called for an unbound wrapper,
# and when binding occurs for a bound wrapper. When being evaluated,
# if 'enabled' is callable it will be called to obtain the value to
# be checked. If False, the wrapper will not be called and instead
# the original wrapped function will be called directly instead.
# The 'proxy' argument provides a way of passing a custom version of
# the FunctionWrapper class used in decorating the function.
if wrapper is not None:
# Helper function for creating wrapper of the appropriate
# time when we need it down below.
def _build(wrapped, wrapper, enabled=None, adapter=None):
if adapter:
if isinstance(adapter, AdapterFactory):
adapter = adapter(wrapped)
if not callable(adapter):
ns = {}
# Check if the signature argument specification has
# annotations. If it does then we need to remember
# it but also drop it when attempting to manufacture
# a standin adapter function. This is necessary else
# it will try and look up any types referenced in
# the annotations in the empty namespace we use,
# which will fail.
annotations = {}
if not isinstance(adapter, string_types):
if len(adapter) == 7:
annotations = adapter[-1]
adapter = adapter[:-1]
adapter = formatargspec(*adapter)
exec_('def adapter{}: pass'.format(adapter), ns, ns)
adapter = ns['adapter']
# Override the annotations for the manufactured
# adapter function so they match the original
# adapter signature argument specification.
if annotations:
adapter.__annotations__ = annotations
return AdapterWrapper(wrapped=wrapped, wrapper=wrapper,
enabled=enabled, adapter=adapter)
return proxy(wrapped=wrapped, wrapper=wrapper, enabled=enabled)
# The wrapper has been provided so return the final decorator.
# The decorator is itself one of our function wrappers so we
# can determine when it is applied to functions, instance methods
# or class methods. This allows us to bind the instance or class
# method so the appropriate self or cls attribute is supplied
# when it is finally called.
def _wrapper(wrapped, instance, args, kwargs):
# We first check for the case where the decorator was applied
# to a class type.
#
# @decorator
# class mydecoratorclass(object):
# def __init__(self, arg=None):
# self.arg = arg
# def __call__(self, wrapped, instance, args, kwargs):
# return wrapped(*args, **kwargs)
#
# @mydecoratorclass(arg=1)
# def function():
# pass
#
# In this case an instance of the class is to be used as the
# decorator wrapper function. If args was empty at this point,
# then it means that there were optional keyword arguments
# supplied to be used when creating an instance of the class
# to be used as the wrapper function.
if instance is None and isclass(wrapped) and not args:
# We still need to be passed the target function to be
# wrapped as yet, so we need to return a further function
# to be able to capture it.
def _capture(target_wrapped):
# Now have the target function to be wrapped and need
# to create an instance of the class which is to act
# as the decorator wrapper function. Before we do that,
# we need to first check that use of the decorator
# hadn't been disabled by a simple boolean. If it was,
# the target function to be wrapped is returned instead.
_enabled = enabled
if type(_enabled) is bool:
if not _enabled:
return target_wrapped
_enabled = None
# Now create an instance of the class which is to act
# as the decorator wrapper function. Any arguments had
# to be supplied as keyword only arguments so that is
# all we pass when creating it.
target_wrapper = wrapped(**kwargs)
# Finally build the wrapper itself and return it.
return _build(target_wrapped, target_wrapper,
_enabled, adapter)
return _capture
# We should always have the target function to be wrapped at
# this point as the first (and only) value in args.
target_wrapped = args[0]
# Need to now check that use of the decorator hadn't been
# disabled by a simple boolean. If it was, then target
# function to be wrapped is returned instead.
_enabled = enabled
if type(_enabled) is bool:
if not _enabled:
return target_wrapped
_enabled = None
# We now need to build the wrapper, but there are a couple of
# different cases we need to consider.
if instance is None:
if isclass(wrapped):
# In this case the decorator was applied to a class
# type but optional keyword arguments were not supplied
# for initialising an instance of the class to be used
# as the decorator wrapper function.
#
# @decorator
# class mydecoratorclass(object):
# def __init__(self, arg=None):
# self.arg = arg
# def __call__(self, wrapped, instance,
# args, kwargs):
# return wrapped(*args, **kwargs)
#
# @mydecoratorclass
# def function():
# pass
#
# We still need to create an instance of the class to
# be used as the decorator wrapper function, but no
# arguments are pass.
target_wrapper = wrapped()
else:
# In this case the decorator was applied to a normal
# function, or possibly a static method of a class.
#
# @decorator
# def mydecoratorfuntion(wrapped, instance,
# args, kwargs):
# return wrapped(*args, **kwargs)
#
# @mydecoratorfunction
# def function():
# pass
#
# That normal function becomes the decorator wrapper
# function.
target_wrapper = wrapper
else:
if isclass(instance):
# In this case the decorator was applied to a class
# method.
#
# class myclass(object):
# @decorator
# @classmethod
# def decoratorclassmethod(cls, wrapped,
# instance, args, kwargs):
# return wrapped(*args, **kwargs)
#
# instance = myclass()
#
# @instance.decoratorclassmethod
# def function():
# pass
#
# This one is a bit strange because binding was actually
# performed on the wrapper created by our decorator
# factory. We need to apply that binding to the decorator
# wrapper function that the decorator factory
# was applied to.
target_wrapper = wrapper.__get__(None, instance)
else:
# In this case the decorator was applied to an instance
# method.
#
# class myclass(object):
# @decorator
# def decoratorclassmethod(self, wrapped,
# instance, args, kwargs):
# return wrapped(*args, **kwargs)
#
# instance = myclass()
#
# @instance.decoratorclassmethod
# def function():
# pass
#
# This one is a bit strange because binding was actually
# performed on the wrapper created by our decorator
# factory. We need to apply that binding to the decorator
# wrapper function that the decorator factory
# was applied to.
target_wrapper = wrapper.__get__(instance, type(instance))
# Finally build the wrapper itself and return it.
return _build(target_wrapped, target_wrapper, _enabled, adapter)
# We first return our magic function wrapper here so we can
# determine in what context the decorator factory was used. In
# other words, it is itself a universal decorator. The decorator
# function is used as the adapter so that linters see a signature
# corresponding to the decorator and not the wrapper it is being
# applied to.
return _build(wrapper, _wrapper, adapter=decorator)
else:
# The wrapper still has not been provided, so we are just
# collecting the optional keyword arguments. Return the
# decorator again wrapped in a partial using the collected
# arguments.
return partial(decorator, enabled=enabled, adapter=adapter,
proxy=proxy)
# Decorator for implementing thread synchronization. It can be used as a
# decorator, in which case the synchronization context is determined by
# what type of function is wrapped, or it can also be used as a context
# manager, where the user needs to supply the correct synchronization
# context. It is also possible to supply an object which appears to be a
# synchronization primitive of some sort, by virtue of having release()
# and acquire() methods. In that case that will be used directly as the
# synchronization primitive without creating a separate lock against the
# derived or supplied context.
def synchronized(wrapped):
# Determine if being passed an object which is a synchronization
# primitive. We can't check by type for Lock, RLock, Semaphore etc,
# as the means of creating them isn't the type. Therefore use the
# existence of acquire() and release() methods. This is more
# extensible anyway as it allows custom synchronization mechanisms.
if hasattr(wrapped, 'acquire') and hasattr(wrapped, 'release'):
# We remember what the original lock is and then return a new
# decorator which accesses and locks it. When returning the new
# decorator we wrap it with an object proxy so we can override
# the context manager methods in case it is being used to wrap
# synchronized statements with a 'with' statement.
lock = wrapped
@decorator
def _synchronized(wrapped, instance, args, kwargs):
# Execute the wrapped function while the original supplied
# lock is held.
with lock:
return wrapped(*args, **kwargs)
class _PartialDecorator(CallableObjectProxy):
def __enter__(self):
lock.acquire()
return lock
def __exit__(self, *args):
lock.release()
return _PartialDecorator(wrapped=_synchronized)
# Following only apply when the lock is being created automatically
# based on the context of what was supplied. In this case we supply
# a final decorator, but need to use FunctionWrapper directly as we
# want to derive from it to add context manager methods in case it is
# being used to wrap synchronized statements with a 'with' statement.
def _synchronized_lock(context):
# Attempt to retrieve the lock for the specific context.
lock = vars(context).get('_synchronized_lock', None)
if lock is None:
# There is no existing lock defined for the context we
# are dealing with so we need to create one. This needs
# to be done in a way to guarantee there is only one
# created, even if multiple threads try and create it at
# the same time. We can't always use the setdefault()
# method on the __dict__ for the context. This is the
# case where the context is a class, as __dict__ is
# actually a dictproxy. What we therefore do is use a
# meta lock on this wrapper itself, to control the
# creation and assignment of the lock attribute against
# the context.
with synchronized._synchronized_meta_lock:
# We need to check again for whether the lock we want
# exists in case two threads were trying to create it
# at the same time and were competing to create the
# meta lock.
lock = vars(context).get('_synchronized_lock', None)
if lock is None:
lock = RLock()
setattr(context, '_synchronized_lock', lock)
return lock
def _synchronized_wrapper(wrapped, instance, args, kwargs):
# Execute the wrapped function while the lock for the
# desired context is held. If instance is None then the
# wrapped function is used as the context.
with _synchronized_lock(instance if instance is not None else wrapped):
return wrapped(*args, **kwargs)
class _FinalDecorator(FunctionWrapper):
def __enter__(self):
self._self_lock = _synchronized_lock(self.__wrapped__)
self._self_lock.acquire()
return self._self_lock
def __exit__(self, *args):
self._self_lock.release()
return _FinalDecorator(wrapped=wrapped, wrapper=_synchronized_wrapper)
synchronized._synchronized_meta_lock = Lock()

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"""This module implements a post import hook mechanism styled after what is
described in PEP-369. Note that it doesn't cope with modules being reloaded.
"""
import sys
import threading
PY2 = sys.version_info[0] == 2
if PY2:
string_types = basestring,
find_spec = None
else:
string_types = str,
from importlib.util import find_spec
from .__wrapt__ import ObjectProxy
# The dictionary registering any post import hooks to be triggered once
# the target module has been imported. Once a module has been imported
# and the hooks fired, the list of hooks recorded against the target
# module will be truncated but the list left in the dictionary. This
# acts as a flag to indicate that the module had already been imported.
_post_import_hooks = {}
_post_import_hooks_init = False
_post_import_hooks_lock = threading.RLock()
# Register a new post import hook for the target module name. This
# differs from the PEP-369 implementation in that it also allows the
# hook function to be specified as a string consisting of the name of
# the callback in the form 'module:function'. This will result in a
# proxy callback being registered which will defer loading of the
# specified module containing the callback function until required.
def _create_import_hook_from_string(name):
def import_hook(module):
module_name, function = name.split(':')
attrs = function.split('.')
__import__(module_name)
callback = sys.modules[module_name]
for attr in attrs:
callback = getattr(callback, attr)
return callback(module)
return import_hook
def register_post_import_hook(hook, name):
# Create a deferred import hook if hook is a string name rather than
# a callable function.
if isinstance(hook, string_types):
hook = _create_import_hook_from_string(hook)
with _post_import_hooks_lock:
# Automatically install the import hook finder if it has not already
# been installed.
global _post_import_hooks_init
if not _post_import_hooks_init:
_post_import_hooks_init = True
sys.meta_path.insert(0, ImportHookFinder())
# Check if the module is already imported. If not, register the hook
# to be called after import.
module = sys.modules.get(name, None)
if module is None:
_post_import_hooks.setdefault(name, []).append(hook)
# If the module is already imported, we fire the hook right away. Note that
# the hook is called outside of the lock to avoid deadlocks if code run as a
# consequence of calling the module import hook in turn triggers a separate
# thread which tries to register an import hook.
if module is not None:
hook(module)
# Register post import hooks defined as package entry points.
def _create_import_hook_from_entrypoint(entrypoint):
def import_hook(module):
__import__(entrypoint.module_name)
callback = sys.modules[entrypoint.module_name]
for attr in entrypoint.attrs:
callback = getattr(callback, attr)
return callback(module)
return import_hook
def discover_post_import_hooks(group):
try:
import pkg_resources
except ImportError:
return
for entrypoint in pkg_resources.iter_entry_points(group=group):
callback = _create_import_hook_from_entrypoint(entrypoint)
register_post_import_hook(callback, entrypoint.name)
# Indicate that a module has been loaded. Any post import hooks which
# were registered against the target module will be invoked. If an
# exception is raised in any of the post import hooks, that will cause
# the import of the target module to fail.
def notify_module_loaded(module):
name = getattr(module, '__name__', None)
with _post_import_hooks_lock:
hooks = _post_import_hooks.pop(name, ())
# Note that the hook is called outside of the lock to avoid deadlocks if
# code run as a consequence of calling the module import hook in turn
# triggers a separate thread which tries to register an import hook.
for hook in hooks:
hook(module)
# A custom module import finder. This intercepts attempts to import
# modules and watches out for attempts to import target modules of
# interest. When a module of interest is imported, then any post import
# hooks which are registered will be invoked.
class _ImportHookLoader:
def load_module(self, fullname):
module = sys.modules[fullname]
notify_module_loaded(module)
return module
class _ImportHookChainedLoader(ObjectProxy):
def __init__(self, loader):
super(_ImportHookChainedLoader, self).__init__(loader)
if hasattr(loader, "load_module"):
self.__self_setattr__('load_module', self._self_load_module)
if hasattr(loader, "create_module"):
self.__self_setattr__('create_module', self._self_create_module)
if hasattr(loader, "exec_module"):
self.__self_setattr__('exec_module', self._self_exec_module)
def _self_set_loader(self, module):
# Set module's loader to self.__wrapped__ unless it's already set to
# something else. Import machinery will set it to spec.loader if it is
# None, so handle None as well. The module may not support attribute
# assignment, in which case we simply skip it. Note that we also deal
# with __loader__ not existing at all. This is to future proof things
# due to proposal to remove the attribue as described in the GitHub
# issue at https://github.com/python/cpython/issues/77458. Also prior
# to Python 3.3, the __loader__ attribute was only set if a custom
# module loader was used. It isn't clear whether the attribute still
# existed in that case or was set to None.
class UNDEFINED: pass
if getattr(module, "__loader__", UNDEFINED) in (None, self):
try:
module.__loader__ = self.__wrapped__
except AttributeError:
pass
if (getattr(module, "__spec__", None) is not None
and getattr(module.__spec__, "loader", None) is self):
module.__spec__.loader = self.__wrapped__
def _self_load_module(self, fullname):
module = self.__wrapped__.load_module(fullname)
self._self_set_loader(module)
notify_module_loaded(module)
return module
# Python 3.4 introduced create_module() and exec_module() instead of
# load_module() alone. Splitting the two steps.
def _self_create_module(self, spec):
return self.__wrapped__.create_module(spec)
def _self_exec_module(self, module):
self._self_set_loader(module)
self.__wrapped__.exec_module(module)
notify_module_loaded(module)
class ImportHookFinder:
def __init__(self):
self.in_progress = {}
def find_module(self, fullname, path=None):
# If the module being imported is not one we have registered
# post import hooks for, we can return immediately. We will
# take no further part in the importing of this module.
with _post_import_hooks_lock:
if fullname not in _post_import_hooks:
return None
# When we are interested in a specific module, we will call back
# into the import system a second time to defer to the import
# finder that is supposed to handle the importing of the module.
# We set an in progress flag for the target module so that on
# the second time through we don't trigger another call back
# into the import system and cause a infinite loop.
if fullname in self.in_progress:
return None
self.in_progress[fullname] = True
# Now call back into the import system again.
try:
if not find_spec:
# For Python 2 we don't have much choice but to
# call back in to __import__(). This will
# actually cause the module to be imported. If no
# module could be found then ImportError will be
# raised. Otherwise we return a loader which
# returns the already loaded module and invokes
# the post import hooks.
__import__(fullname)
return _ImportHookLoader()
else:
# For Python 3 we need to use find_spec().loader
# from the importlib.util module. It doesn't actually
# import the target module and only finds the
# loader. If a loader is found, we need to return
# our own loader which will then in turn call the
# real loader to import the module and invoke the
# post import hooks.
loader = getattr(find_spec(fullname), "loader", None)
if loader and not isinstance(loader, _ImportHookChainedLoader):
return _ImportHookChainedLoader(loader)
finally:
del self.in_progress[fullname]
def find_spec(self, fullname, path=None, target=None):
# Since Python 3.4, you are meant to implement find_spec() method
# instead of find_module() and since Python 3.10 you get deprecation
# warnings if you don't define find_spec().
# If the module being imported is not one we have registered
# post import hooks for, we can return immediately. We will
# take no further part in the importing of this module.
with _post_import_hooks_lock:
if fullname not in _post_import_hooks:
return None
# When we are interested in a specific module, we will call back
# into the import system a second time to defer to the import
# finder that is supposed to handle the importing of the module.
# We set an in progress flag for the target module so that on
# the second time through we don't trigger another call back
# into the import system and cause a infinite loop.
if fullname in self.in_progress:
return None
self.in_progress[fullname] = True
# Now call back into the import system again.
try:
# This should only be Python 3 so find_spec() should always
# exist so don't need to check.
spec = find_spec(fullname)
loader = getattr(spec, "loader", None)
if loader and not isinstance(loader, _ImportHookChainedLoader):
spec.loader = _ImportHookChainedLoader(loader)
return spec
finally:
del self.in_progress[fullname]
# Decorator for marking that a function should be called as a post
# import hook when the target module is imported.
def when_imported(name):
def register(hook):
register_post_import_hook(hook, name)
return hook
return register

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import inspect
import sys
PY2 = sys.version_info[0] == 2
if PY2:
string_types = basestring,
else:
string_types = str,
from .__wrapt__ import FunctionWrapper
# Helper functions for applying wrappers to existing functions.
def resolve_path(module, name):
if isinstance(module, string_types):
__import__(module)
module = sys.modules[module]
parent = module
path = name.split('.')
attribute = path[0]
# We can't just always use getattr() because in doing
# that on a class it will cause binding to occur which
# will complicate things later and cause some things not
# to work. For the case of a class we therefore access
# the __dict__ directly. To cope though with the wrong
# class being given to us, or a method being moved into
# a base class, we need to walk the class hierarchy to
# work out exactly which __dict__ the method was defined
# in, as accessing it from __dict__ will fail if it was
# not actually on the class given. Fallback to using
# getattr() if we can't find it. If it truly doesn't
# exist, then that will fail.
def lookup_attribute(parent, attribute):
if inspect.isclass(parent):
for cls in inspect.getmro(parent):
if attribute in vars(cls):
return vars(cls)[attribute]
else:
return getattr(parent, attribute)
else:
return getattr(parent, attribute)
original = lookup_attribute(parent, attribute)
for attribute in path[1:]:
parent = original
original = lookup_attribute(parent, attribute)
return (parent, attribute, original)
def apply_patch(parent, attribute, replacement):
setattr(parent, attribute, replacement)
def wrap_object(module, name, factory, args=(), kwargs={}):
(parent, attribute, original) = resolve_path(module, name)
wrapper = factory(original, *args, **kwargs)
apply_patch(parent, attribute, wrapper)
return wrapper
# Function for applying a proxy object to an attribute of a class
# instance. The wrapper works by defining an attribute of the same name
# on the class which is a descriptor and which intercepts access to the
# instance attribute. Note that this cannot be used on attributes which
# are themselves defined by a property object.
class AttributeWrapper(object):
def __init__(self, attribute, factory, args, kwargs):
self.attribute = attribute
self.factory = factory
self.args = args
self.kwargs = kwargs
def __get__(self, instance, owner):
value = instance.__dict__[self.attribute]
return self.factory(value, *self.args, **self.kwargs)
def __set__(self, instance, value):
instance.__dict__[self.attribute] = value
def __delete__(self, instance):
del instance.__dict__[self.attribute]
def wrap_object_attribute(module, name, factory, args=(), kwargs={}):
path, attribute = name.rsplit('.', 1)
parent = resolve_path(module, path)[2]
wrapper = AttributeWrapper(attribute, factory, args, kwargs)
apply_patch(parent, attribute, wrapper)
return wrapper
# Functions for creating a simple decorator using a FunctionWrapper,
# plus short cut functions for applying wrappers to functions. These are
# for use when doing monkey patching. For a more featured way of
# creating decorators see the decorator decorator instead.
def function_wrapper(wrapper):
def _wrapper(wrapped, instance, args, kwargs):
target_wrapped = args[0]
if instance is None:
target_wrapper = wrapper
elif inspect.isclass(instance):
target_wrapper = wrapper.__get__(None, instance)
else:
target_wrapper = wrapper.__get__(instance, type(instance))
return FunctionWrapper(target_wrapped, target_wrapper)
return FunctionWrapper(wrapper, _wrapper)
def wrap_function_wrapper(module, name, wrapper):
return wrap_object(module, name, FunctionWrapper, (wrapper,))
def patch_function_wrapper(module, name, enabled=None):
def _wrapper(wrapper):
return wrap_object(module, name, FunctionWrapper, (wrapper, enabled))
return _wrapper
def transient_function_wrapper(module, name):
def _decorator(wrapper):
def _wrapper(wrapped, instance, args, kwargs):
target_wrapped = args[0]
if instance is None:
target_wrapper = wrapper
elif inspect.isclass(instance):
target_wrapper = wrapper.__get__(None, instance)
else:
target_wrapper = wrapper.__get__(instance, type(instance))
def _execute(wrapped, instance, args, kwargs):
(parent, attribute, original) = resolve_path(module, name)
replacement = FunctionWrapper(original, target_wrapper)
setattr(parent, attribute, replacement)
try:
return wrapped(*args, **kwargs)
finally:
setattr(parent, attribute, original)
return FunctionWrapper(target_wrapped, _execute)
return FunctionWrapper(wrapper, _wrapper)
return _decorator

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import functools
import weakref
from .__wrapt__ import ObjectProxy, _FunctionWrapperBase
# A weak function proxy. This will work on instance methods, class
# methods, static methods and regular functions. Special treatment is
# needed for the method types because the bound method is effectively a
# transient object and applying a weak reference to one will immediately
# result in it being destroyed and the weakref callback called. The weak
# reference is therefore applied to the instance the method is bound to
# and the original function. The function is then rebound at the point
# of a call via the weak function proxy.
def _weak_function_proxy_callback(ref, proxy, callback):
if proxy._self_expired:
return
proxy._self_expired = True
# This could raise an exception. We let it propagate back and let
# the weakref.proxy() deal with it, at which point it generally
# prints out a short error message direct to stderr and keeps going.
if callback is not None:
callback(proxy)
class WeakFunctionProxy(ObjectProxy):
__slots__ = ('_self_expired', '_self_instance')
def __init__(self, wrapped, callback=None):
# We need to determine if the wrapped function is actually a
# bound method. In the case of a bound method, we need to keep a
# reference to the original unbound function and the instance.
# This is necessary because if we hold a reference to the bound
# function, it will be the only reference and given it is a
# temporary object, it will almost immediately expire and
# the weakref callback triggered. So what is done is that we
# hold a reference to the instance and unbound function and
# when called bind the function to the instance once again and
# then call it. Note that we avoid using a nested function for
# the callback here so as not to cause any odd reference cycles.
_callback = callback and functools.partial(
_weak_function_proxy_callback, proxy=self,
callback=callback)
self._self_expired = False
if isinstance(wrapped, _FunctionWrapperBase):
self._self_instance = weakref.ref(wrapped._self_instance,
_callback)
if wrapped._self_parent is not None:
super(WeakFunctionProxy, self).__init__(
weakref.proxy(wrapped._self_parent, _callback))
else:
super(WeakFunctionProxy, self).__init__(
weakref.proxy(wrapped, _callback))
return
try:
self._self_instance = weakref.ref(wrapped.__self__, _callback)
super(WeakFunctionProxy, self).__init__(
weakref.proxy(wrapped.__func__, _callback))
except AttributeError:
self._self_instance = None
super(WeakFunctionProxy, self).__init__(
weakref.proxy(wrapped, _callback))
def __call__(*args, **kwargs):
def _unpack_self(self, *args):
return self, args
self, args = _unpack_self(*args)
# We perform a boolean check here on the instance and wrapped
# function as that will trigger the reference error prior to
# calling if the reference had expired.
instance = self._self_instance and self._self_instance()
function = self.__wrapped__ and self.__wrapped__
# If the wrapped function was originally a bound function, for
# which we retained a reference to the instance and the unbound
# function we need to rebind the function and then call it. If
# not just called the wrapped function.
if instance is None:
return self.__wrapped__(*args, **kwargs)
return function.__get__(instance, type(instance))(*args, **kwargs)

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import sys
import operator
import inspect
PY2 = sys.version_info[0] == 2
if PY2:
string_types = basestring,
else:
string_types = str,
def with_metaclass(meta, *bases):
"""Create a base class with a metaclass."""
return meta("NewBase", bases, {})
class _ObjectProxyMethods(object):
# We use properties to override the values of __module__ and
# __doc__. If we add these in ObjectProxy, the derived class
# __dict__ will still be setup to have string variants of these
# attributes and the rules of descriptors means that they appear to
# take precedence over the properties in the base class. To avoid
# that, we copy the properties into the derived class type itself
# via a meta class. In that way the properties will always take
# precedence.
@property
def __module__(self):
return self.__wrapped__.__module__
@__module__.setter
def __module__(self, value):
self.__wrapped__.__module__ = value
@property
def __doc__(self):
return self.__wrapped__.__doc__
@__doc__.setter
def __doc__(self, value):
self.__wrapped__.__doc__ = value
# We similar use a property for __dict__. We need __dict__ to be
# explicit to ensure that vars() works as expected.
@property
def __dict__(self):
return self.__wrapped__.__dict__
# Need to also propagate the special __weakref__ attribute for case
# where decorating classes which will define this. If do not define
# it and use a function like inspect.getmembers() on a decorator
# class it will fail. This can't be in the derived classes.
@property
def __weakref__(self):
return self.__wrapped__.__weakref__
class _ObjectProxyMetaType(type):
def __new__(cls, name, bases, dictionary):
# Copy our special properties into the class so that they
# always take precedence over attributes of the same name added
# during construction of a derived class. This is to save
# duplicating the implementation for them in all derived classes.
dictionary.update(vars(_ObjectProxyMethods))
return type.__new__(cls, name, bases, dictionary)
class ObjectProxy(with_metaclass(_ObjectProxyMetaType)):
__slots__ = '__wrapped__'
def __init__(self, wrapped):
object.__setattr__(self, '__wrapped__', wrapped)
# Python 3.2+ has the __qualname__ attribute, but it does not
# allow it to be overridden using a property and it must instead
# be an actual string object instead.
try:
object.__setattr__(self, '__qualname__', wrapped.__qualname__)
except AttributeError:
pass
# Python 3.10 onwards also does not allow itself to be overridden
# using a property and it must instead be set explicitly.
try:
object.__setattr__(self, '__annotations__', wrapped.__annotations__)
except AttributeError:
pass
def __self_setattr__(self, name, value):
object.__setattr__(self, name, value)
@property
def __name__(self):
return self.__wrapped__.__name__
@__name__.setter
def __name__(self, value):
self.__wrapped__.__name__ = value
@property
def __class__(self):
return self.__wrapped__.__class__
@__class__.setter
def __class__(self, value):
self.__wrapped__.__class__ = value
def __dir__(self):
return dir(self.__wrapped__)
def __str__(self):
return str(self.__wrapped__)
if not PY2:
def __bytes__(self):
return bytes(self.__wrapped__)
def __repr__(self):
return '<{} at 0x{:x} for {} at 0x{:x}>'.format(
type(self).__name__, id(self),
type(self.__wrapped__).__name__,
id(self.__wrapped__))
def __format__(self, format_spec):
return format(self.__wrapped__, format_spec)
def __reversed__(self):
return reversed(self.__wrapped__)
if not PY2:
def __round__(self, ndigits=None):
return round(self.__wrapped__, ndigits)
if sys.hexversion >= 0x03070000:
def __mro_entries__(self, bases):
return (self.__wrapped__,)
def __lt__(self, other):
return self.__wrapped__ < other
def __le__(self, other):
return self.__wrapped__ <= other
def __eq__(self, other):
return self.__wrapped__ == other
def __ne__(self, other):
return self.__wrapped__ != other
def __gt__(self, other):
return self.__wrapped__ > other
def __ge__(self, other):
return self.__wrapped__ >= other
def __hash__(self):
return hash(self.__wrapped__)
def __nonzero__(self):
return bool(self.__wrapped__)
def __bool__(self):
return bool(self.__wrapped__)
def __setattr__(self, name, value):
if name.startswith('_self_'):
object.__setattr__(self, name, value)
elif name == '__wrapped__':
object.__setattr__(self, name, value)
try:
object.__delattr__(self, '__qualname__')
except AttributeError:
pass
try:
object.__setattr__(self, '__qualname__', value.__qualname__)
except AttributeError:
pass
try:
object.__delattr__(self, '__annotations__')
except AttributeError:
pass
try:
object.__setattr__(self, '__annotations__', value.__annotations__)
except AttributeError:
pass
elif name == '__qualname__':
setattr(self.__wrapped__, name, value)
object.__setattr__(self, name, value)
elif name == '__annotations__':
setattr(self.__wrapped__, name, value)
object.__setattr__(self, name, value)
elif hasattr(type(self), name):
object.__setattr__(self, name, value)
else:
setattr(self.__wrapped__, name, value)
def __getattr__(self, name):
# If we are being to lookup '__wrapped__' then the
# '__init__()' method cannot have been called.
if name == '__wrapped__':
raise ValueError('wrapper has not been initialised')
return getattr(self.__wrapped__, name)
def __delattr__(self, name):
if name.startswith('_self_'):
object.__delattr__(self, name)
elif name == '__wrapped__':
raise TypeError('__wrapped__ must be an object')
elif name == '__qualname__':
object.__delattr__(self, name)
delattr(self.__wrapped__, name)
elif hasattr(type(self), name):
object.__delattr__(self, name)
else:
delattr(self.__wrapped__, name)
def __add__(self, other):
return self.__wrapped__ + other
def __sub__(self, other):
return self.__wrapped__ - other
def __mul__(self, other):
return self.__wrapped__ * other
def __div__(self, other):
return operator.div(self.__wrapped__, other)
def __truediv__(self, other):
return operator.truediv(self.__wrapped__, other)
def __floordiv__(self, other):
return self.__wrapped__ // other
def __mod__(self, other):
return self.__wrapped__ % other
def __divmod__(self, other):
return divmod(self.__wrapped__, other)
def __pow__(self, other, *args):
return pow(self.__wrapped__, other, *args)
def __lshift__(self, other):
return self.__wrapped__ << other
def __rshift__(self, other):
return self.__wrapped__ >> other
def __and__(self, other):
return self.__wrapped__ & other
def __xor__(self, other):
return self.__wrapped__ ^ other
def __or__(self, other):
return self.__wrapped__ | other
def __radd__(self, other):
return other + self.__wrapped__
def __rsub__(self, other):
return other - self.__wrapped__
def __rmul__(self, other):
return other * self.__wrapped__
def __rdiv__(self, other):
return operator.div(other, self.__wrapped__)
def __rtruediv__(self, other):
return operator.truediv(other, self.__wrapped__)
def __rfloordiv__(self, other):
return other // self.__wrapped__
def __rmod__(self, other):
return other % self.__wrapped__
def __rdivmod__(self, other):
return divmod(other, self.__wrapped__)
def __rpow__(self, other, *args):
return pow(other, self.__wrapped__, *args)
def __rlshift__(self, other):
return other << self.__wrapped__
def __rrshift__(self, other):
return other >> self.__wrapped__
def __rand__(self, other):
return other & self.__wrapped__
def __rxor__(self, other):
return other ^ self.__wrapped__
def __ror__(self, other):
return other | self.__wrapped__
def __iadd__(self, other):
self.__wrapped__ += other
return self
def __isub__(self, other):
self.__wrapped__ -= other
return self
def __imul__(self, other):
self.__wrapped__ *= other
return self
def __idiv__(self, other):
self.__wrapped__ = operator.idiv(self.__wrapped__, other)
return self
def __itruediv__(self, other):
self.__wrapped__ = operator.itruediv(self.__wrapped__, other)
return self
def __ifloordiv__(self, other):
self.__wrapped__ //= other
return self
def __imod__(self, other):
self.__wrapped__ %= other
return self
def __ipow__(self, other):
self.__wrapped__ **= other
return self
def __ilshift__(self, other):
self.__wrapped__ <<= other
return self
def __irshift__(self, other):
self.__wrapped__ >>= other
return self
def __iand__(self, other):
self.__wrapped__ &= other
return self
def __ixor__(self, other):
self.__wrapped__ ^= other
return self
def __ior__(self, other):
self.__wrapped__ |= other
return self
def __neg__(self):
return -self.__wrapped__
def __pos__(self):
return +self.__wrapped__
def __abs__(self):
return abs(self.__wrapped__)
def __invert__(self):
return ~self.__wrapped__
def __int__(self):
return int(self.__wrapped__)
def __long__(self):
return long(self.__wrapped__)
def __float__(self):
return float(self.__wrapped__)
def __complex__(self):
return complex(self.__wrapped__)
def __oct__(self):
return oct(self.__wrapped__)
def __hex__(self):
return hex(self.__wrapped__)
def __index__(self):
return operator.index(self.__wrapped__)
def __len__(self):
return len(self.__wrapped__)
def __contains__(self, value):
return value in self.__wrapped__
def __getitem__(self, key):
return self.__wrapped__[key]
def __setitem__(self, key, value):
self.__wrapped__[key] = value
def __delitem__(self, key):
del self.__wrapped__[key]
def __getslice__(self, i, j):
return self.__wrapped__[i:j]
def __setslice__(self, i, j, value):
self.__wrapped__[i:j] = value
def __delslice__(self, i, j):
del self.__wrapped__[i:j]
def __enter__(self):
return self.__wrapped__.__enter__()
def __exit__(self, *args, **kwargs):
return self.__wrapped__.__exit__(*args, **kwargs)
def __iter__(self):
return iter(self.__wrapped__)
def __copy__(self):
raise NotImplementedError('object proxy must define __copy__()')
def __deepcopy__(self, memo):
raise NotImplementedError('object proxy must define __deepcopy__()')
def __reduce__(self):
raise NotImplementedError(
'object proxy must define __reduce__()')
def __reduce_ex__(self, protocol):
raise NotImplementedError(
'object proxy must define __reduce_ex__()')
class CallableObjectProxy(ObjectProxy):
def __call__(*args, **kwargs):
def _unpack_self(self, *args):
return self, args
self, args = _unpack_self(*args)
return self.__wrapped__(*args, **kwargs)
class PartialCallableObjectProxy(ObjectProxy):
def __init__(*args, **kwargs):
def _unpack_self(self, *args):
return self, args
self, args = _unpack_self(*args)
if len(args) < 1:
raise TypeError('partial type takes at least one argument')
wrapped, args = args[0], args[1:]
if not callable(wrapped):
raise TypeError('the first argument must be callable')
super(PartialCallableObjectProxy, self).__init__(wrapped)
self._self_args = args
self._self_kwargs = kwargs
def __call__(*args, **kwargs):
def _unpack_self(self, *args):
return self, args
self, args = _unpack_self(*args)
_args = self._self_args + args
_kwargs = dict(self._self_kwargs)
_kwargs.update(kwargs)
return self.__wrapped__(*_args, **_kwargs)
class _FunctionWrapperBase(ObjectProxy):
__slots__ = ('_self_instance', '_self_wrapper', '_self_enabled',
'_self_binding', '_self_parent', '_self_owner')
def __init__(self, wrapped, instance, wrapper, enabled=None,
binding='callable', parent=None, owner=None):
super(_FunctionWrapperBase, self).__init__(wrapped)
object.__setattr__(self, '_self_instance', instance)
object.__setattr__(self, '_self_wrapper', wrapper)
object.__setattr__(self, '_self_enabled', enabled)
object.__setattr__(self, '_self_binding', binding)
object.__setattr__(self, '_self_parent', parent)
object.__setattr__(self, '_self_owner', owner)
def __get__(self, instance, owner):
# This method is actually doing double duty for both unbound and bound
# derived wrapper classes. It should possibly be broken up and the
# distinct functionality moved into the derived classes. Can't do that
# straight away due to some legacy code which is relying on it being
# here in this base class.
#
# The distinguishing attribute which determines whether we are being
# called in an unbound or bound wrapper is the parent attribute. If
# binding has never occurred, then the parent will be None.
#
# First therefore, is if we are called in an unbound wrapper. In this
# case we perform the binding.
#
# We have two special cases to worry about here. These are where we are
# decorating a class or builtin function as neither provide a __get__()
# method to call. In this case we simply return self.
#
# Note that we otherwise still do binding even if instance is None and
# accessing an unbound instance method from a class. This is because we
# need to be able to later detect that specific case as we will need to
# extract the instance from the first argument of those passed in.
if self._self_parent is None:
# Technically can probably just check for existence of __get__ on
# the wrapped object, but this is more explicit.
if self._self_binding == 'builtin':
return self
if self._self_binding == "class":
return self
binder = getattr(self.__wrapped__, '__get__', None)
if binder is None:
return self
descriptor = binder(instance, owner)
return self.__bound_function_wrapper__(descriptor, instance,
self._self_wrapper, self._self_enabled,
self._self_binding, self, owner)
# Now we have the case of binding occurring a second time on what was
# already a bound function. In this case we would usually return
# ourselves again. This mirrors what Python does.
#
# The special case this time is where we were originally bound with an
# instance of None and we were likely an instance method. In that case
# we rebind against the original wrapped function from the parent again.
if self._self_instance is None and self._self_binding in ('function', 'instancemethod', 'callable'):
descriptor = self._self_parent.__wrapped__.__get__(
instance, owner)
return self._self_parent.__bound_function_wrapper__(
descriptor, instance, self._self_wrapper,
self._self_enabled, self._self_binding,
self._self_parent, owner)
return self
def __call__(*args, **kwargs):
def _unpack_self(self, *args):
return self, args
self, args = _unpack_self(*args)
# If enabled has been specified, then evaluate it at this point
# and if the wrapper is not to be executed, then simply return
# the bound function rather than a bound wrapper for the bound
# function. When evaluating enabled, if it is callable we call
# it, otherwise we evaluate it as a boolean.
if self._self_enabled is not None:
if callable(self._self_enabled):
if not self._self_enabled():
return self.__wrapped__(*args, **kwargs)
elif not self._self_enabled:
return self.__wrapped__(*args, **kwargs)
# This can occur where initial function wrapper was applied to
# a function that was already bound to an instance. In that case
# we want to extract the instance from the function and use it.
if self._self_binding in ('function', 'instancemethod', 'classmethod', 'callable'):
if self._self_instance is None:
instance = getattr(self.__wrapped__, '__self__', None)
if instance is not None:
return self._self_wrapper(self.__wrapped__, instance,
args, kwargs)
# This is generally invoked when the wrapped function is being
# called as a normal function and is not bound to a class as an
# instance method. This is also invoked in the case where the
# wrapped function was a method, but this wrapper was in turn
# wrapped using the staticmethod decorator.
return self._self_wrapper(self.__wrapped__, self._self_instance,
args, kwargs)
def __set_name__(self, owner, name):
# This is a special method use to supply information to
# descriptors about what the name of variable in a class
# definition is. Not wanting to add this to ObjectProxy as not
# sure of broader implications of doing that. Thus restrict to
# FunctionWrapper used by decorators.
if hasattr(self.__wrapped__, "__set_name__"):
self.__wrapped__.__set_name__(owner, name)
def __instancecheck__(self, instance):
# This is a special method used by isinstance() to make checks
# instance of the `__wrapped__`.
return isinstance(instance, self.__wrapped__)
def __subclasscheck__(self, subclass):
# This is a special method used by issubclass() to make checks
# about inheritance of classes. We need to upwrap any object
# proxy. Not wanting to add this to ObjectProxy as not sure of
# broader implications of doing that. Thus restrict to
# FunctionWrapper used by decorators.
if hasattr(subclass, "__wrapped__"):
return issubclass(subclass.__wrapped__, self.__wrapped__)
else:
return issubclass(subclass, self.__wrapped__)
class BoundFunctionWrapper(_FunctionWrapperBase):
def __call__(*args, **kwargs):
def _unpack_self(self, *args):
return self, args
self, args = _unpack_self(*args)
# If enabled has been specified, then evaluate it at this point and if
# the wrapper is not to be executed, then simply return the bound
# function rather than a bound wrapper for the bound function. When
# evaluating enabled, if it is callable we call it, otherwise we
# evaluate it as a boolean.
if self._self_enabled is not None:
if callable(self._self_enabled):
if not self._self_enabled():
return self.__wrapped__(*args, **kwargs)
elif not self._self_enabled:
return self.__wrapped__(*args, **kwargs)
# We need to do things different depending on whether we are likely
# wrapping an instance method vs a static method or class method.
if self._self_binding == 'function':
if self._self_instance is None and args:
instance, newargs = args[0], args[1:]
if isinstance(instance, self._self_owner):
wrapped = PartialCallableObjectProxy(self.__wrapped__, instance)
return self._self_wrapper(wrapped, instance, newargs, kwargs)
return self._self_wrapper(self.__wrapped__, self._self_instance,
args, kwargs)
elif self._self_binding == 'callable':
if self._self_instance is None:
# This situation can occur where someone is calling the
# instancemethod via the class type and passing the instance as
# the first argument. We need to shift the args before making
# the call to the wrapper and effectively bind the instance to
# the wrapped function using a partial so the wrapper doesn't
# see anything as being different.
if not args:
raise TypeError('missing 1 required positional argument')
instance, args = args[0], args[1:]
wrapped = PartialCallableObjectProxy(self.__wrapped__, instance)
return self._self_wrapper(wrapped, instance, args, kwargs)
return self._self_wrapper(self.__wrapped__, self._self_instance,
args, kwargs)
else:
# As in this case we would be dealing with a classmethod or
# staticmethod, then _self_instance will only tell us whether
# when calling the classmethod or staticmethod they did it via an
# instance of the class it is bound to and not the case where
# done by the class type itself. We thus ignore _self_instance
# and use the __self__ attribute of the bound function instead.
# For a classmethod, this means instance will be the class type
# and for a staticmethod it will be None. This is probably the
# more useful thing we can pass through even though we loose
# knowledge of whether they were called on the instance vs the
# class type, as it reflects what they have available in the
# decoratored function.
instance = getattr(self.__wrapped__, '__self__', None)
return self._self_wrapper(self.__wrapped__, instance, args,
kwargs)
class FunctionWrapper(_FunctionWrapperBase):
__bound_function_wrapper__ = BoundFunctionWrapper
def __init__(self, wrapped, wrapper, enabled=None):
# What it is we are wrapping here could be anything. We need to
# try and detect specific cases though. In particular, we need
# to detect when we are given something that is a method of a
# class. Further, we need to know when it is likely an instance
# method, as opposed to a class or static method. This can
# become problematic though as there isn't strictly a fool proof
# method of knowing.
#
# The situations we could encounter when wrapping a method are:
#
# 1. The wrapper is being applied as part of a decorator which
# is a part of the class definition. In this case what we are
# given is the raw unbound function, classmethod or staticmethod
# wrapper objects.
#
# The problem here is that we will not know we are being applied
# in the context of the class being set up. This becomes
# important later for the case of an instance method, because in
# that case we just see it as a raw function and can't
# distinguish it from wrapping a normal function outside of
# a class context.
#
# 2. The wrapper is being applied when performing monkey
# patching of the class type afterwards and the method to be
# wrapped was retrieved direct from the __dict__ of the class
# type. This is effectively the same as (1) above.
#
# 3. The wrapper is being applied when performing monkey
# patching of the class type afterwards and the method to be
# wrapped was retrieved from the class type. In this case
# binding will have been performed where the instance against
# which the method is bound will be None at that point.
#
# This case is a problem because we can no longer tell if the
# method was a static method, plus if using Python3, we cannot
# tell if it was an instance method as the concept of an
# unnbound method no longer exists.
#
# 4. The wrapper is being applied when performing monkey
# patching of an instance of a class. In this case binding will
# have been perfomed where the instance was not None.
#
# This case is a problem because we can no longer tell if the
# method was a static method.
#
# Overall, the best we can do is look at the original type of the
# object which was wrapped prior to any binding being done and
# see if it is an instance of classmethod or staticmethod. In
# the case where other decorators are between us and them, if
# they do not propagate the __class__ attribute so that the
# isinstance() checks works, then likely this will do the wrong
# thing where classmethod and staticmethod are used.
#
# Since it is likely to be very rare that anyone even puts
# decorators around classmethod and staticmethod, likelihood of
# that being an issue is very small, so we accept it and suggest
# that those other decorators be fixed. It is also only an issue
# if a decorator wants to actually do things with the arguments.
#
# As to not being able to identify static methods properly, we
# just hope that that isn't something people are going to want
# to wrap, or if they do suggest they do it the correct way by
# ensuring that it is decorated in the class definition itself,
# or patch it in the __dict__ of the class type.
#
# So to get the best outcome we can, whenever we aren't sure what
# it is, we label it as a 'callable'. If it was already bound and
# that is rebound later, we assume that it will be an instance
# method and try and cope with the possibility that the 'self'
# argument it being passed as an explicit argument and shuffle
# the arguments around to extract 'self' for use as the instance.
binding = None
if isinstance(wrapped, _FunctionWrapperBase):
binding = wrapped._self_binding
if not binding:
if inspect.isbuiltin(wrapped):
binding = 'builtin'
elif inspect.isfunction(wrapped):
binding = 'function'
elif inspect.isclass(wrapped):
binding = 'class'
elif isinstance(wrapped, classmethod):
binding = 'classmethod'
elif isinstance(wrapped, staticmethod):
binding = 'staticmethod'
elif hasattr(wrapped, '__self__'):
if inspect.isclass(wrapped.__self__):
binding = 'classmethod'
elif inspect.ismethod(wrapped):
binding = 'instancemethod'
else:
binding = 'callable'
else:
binding = 'callable'
super(FunctionWrapper, self).__init__(wrapped, None, wrapper,
enabled, binding)