Source code for spack.util.pattern

# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
# SPDX-License-Identifier: (Apache-2.0 OR MIT)

import functools
import inspect

from llnl.util.compat import MutableSequence

[docs]class Delegate(object): def __init__(self, name, container): = name self.container = container def __call__(self, *args, **kwargs): return [getattr(item,*args, **kwargs) for item in self.container]
[docs]class Composite(list): def __init__(self, fns_to_delegate): self.fns_to_delegate = fns_to_delegate def __getattr__(self, name): if name != 'fns_to_delegate' and name in self.fns_to_delegate: return Delegate(name, self) else: return self.__getattribute__(name)
[docs]def composite(interface=None, method_list=None, container=list): """Decorator implementing the GoF composite pattern. Args: interface (type): class exposing the interface to which the composite object must conform. Only non-private and non-special methods will be taken into account method_list (list): names of methods that should be part of the composite container (MutableSequence): container for the composite object (default = list). Must fulfill the MutableSequence contract. The composite class will expose the container API to manage object composition Returns: a class decorator that patches a class adding all the methods it needs to be a composite for a given interface. """ # Check if container fulfills the MutableSequence contract and raise an # exception if it doesn't. The patched class returned by the decorator will # inherit from the container class to expose the interface needed to manage # objects composition if not issubclass(container, MutableSequence): raise TypeError("Container must fulfill the MutableSequence contract") # Check if at least one of the 'interface' or the 'method_list' arguments # are defined if interface is None and method_list is None: raise TypeError( "Either 'interface' or 'method_list' must be defined on a call " "to composite") def cls_decorator(cls): # Retrieve the base class of the composite. Inspect its methods and # decide which ones will be overridden def no_special_no_private(x): return callable(x) and not x.__name__.startswith('_') # Patch the behavior of each of the methods in the previous list. # This is done associating an instance of the descriptor below to # any method that needs to be patched. class IterateOver(object): """Decorator used to patch methods in a composite. It iterates over all the items in the instance containing the associated attribute and calls for each of them an attribute with the same name """ def __init__(self, name, func=None): = name self.func = func def __get__(self, instance, owner): def getter(*args, **kwargs): for item in instance: getattr(item,*args, **kwargs) # If we are using this descriptor to wrap a method from an # interface, then we must conditionally use the # `functools.wraps` decorator to set the appropriate fields if self.func is not None: getter = functools.wraps(self.func)(getter) return getter dictionary_for_type_call = {} # Construct a dictionary with the methods explicitly passed as name if method_list is not None: dictionary_for_type_call.update( (name, IterateOver(name)) for name in method_list) # Construct a dictionary with the methods inspected from the interface if interface is not None: dictionary_for_type_call.update( (name, IterateOver(name, method)) for name, method in inspect.getmembers( interface, predicate=no_special_no_private)) # Get the methods that are defined in the scope of the composite # class and override any previous definition dictionary_for_type_call.update( (name, method) for name, method in inspect.getmembers( cls, predicate=inspect.ismethod)) # Generate the new class on the fly and return it # FIXME : inherit from interface if we start to use ABC classes? wrapper_class = type(cls.__name__, (cls, container), dictionary_for_type_call) return wrapper_class return cls_decorator
[docs]class Bunch(object): """Carries a bunch of named attributes (from Alex Martelli bunch)""" def __init__(self, **kwargs): self.__dict__.update(kwargs)
[docs]class Args(Bunch): """Subclass of Bunch to write argparse args more naturally.""" def __init__(self, *flags, **kwargs): super(Args, self).__init__(flags=tuple(flags), kwargs=kwargs)