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author | Damien <damien.p.george@gmail.com> | 2013-12-29 18:21:02 +0000 |
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committer | Damien <damien.p.george@gmail.com> | 2013-12-29 18:21:02 +0000 |
commit | 2eda70874ef193c609207db2ba87324244afcf84 (patch) | |
tree | 5a570df6296c40f7774d6d25cd3cc4c38fc1e1ff /tests/bytecode/pylib-tests/abc.py | |
parent | de690d128bbec4f53e8a7d6149738a6facae4382 (diff) | |
download | micropython-2eda70874ef193c609207db2ba87324244afcf84.tar.gz micropython-2eda70874ef193c609207db2ba87324244afcf84.zip |
Add tests to test compiler and emitted byte code.
Diffstat (limited to 'tests/bytecode/pylib-tests/abc.py')
-rw-r--r-- | tests/bytecode/pylib-tests/abc.py | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/tests/bytecode/pylib-tests/abc.py b/tests/bytecode/pylib-tests/abc.py new file mode 100644 index 0000000000..09778e8609 --- /dev/null +++ b/tests/bytecode/pylib-tests/abc.py @@ -0,0 +1,228 @@ +# Copyright 2007 Google, Inc. All Rights Reserved. +# Licensed to PSF under a Contributor Agreement. + +"""Abstract Base Classes (ABCs) according to PEP 3119.""" + +from _weakrefset import WeakSet + +def abstractmethod(funcobj): + """A decorator indicating abstract methods. + + Requires that the metaclass is ABCMeta or derived from it. A + class that has a metaclass derived from ABCMeta cannot be + instantiated unless all of its abstract methods are overridden. + The abstract methods can be called using any of the normal + 'super' call mechanisms. + + Usage: + + class C(metaclass=ABCMeta): + @abstractmethod + def my_abstract_method(self, ...): + ... + """ + funcobj.__isabstractmethod__ = True + return funcobj + + +class abstractclassmethod(classmethod): + """ + A decorator indicating abstract classmethods. + + Similar to abstractmethod. + + Usage: + + class C(metaclass=ABCMeta): + @abstractclassmethod + def my_abstract_classmethod(cls, ...): + ... + + 'abstractclassmethod' is deprecated. Use 'classmethod' with + 'abstractmethod' instead. + """ + + __isabstractmethod__ = True + + def __init__(self, callable): + callable.__isabstractmethod__ = True + super().__init__(callable) + + +class abstractstaticmethod(staticmethod): + """ + A decorator indicating abstract staticmethods. + + Similar to abstractmethod. + + Usage: + + class C(metaclass=ABCMeta): + @abstractstaticmethod + def my_abstract_staticmethod(...): + ... + + 'abstractstaticmethod' is deprecated. Use 'staticmethod' with + 'abstractmethod' instead. + """ + + __isabstractmethod__ = True + + def __init__(self, callable): + callable.__isabstractmethod__ = True + super().__init__(callable) + + +class abstractproperty(property): + """ + A decorator indicating abstract properties. + + Requires that the metaclass is ABCMeta or derived from it. A + class that has a metaclass derived from ABCMeta cannot be + instantiated unless all of its abstract properties are overridden. + The abstract properties can be called using any of the normal + 'super' call mechanisms. + + Usage: + + class C(metaclass=ABCMeta): + @abstractproperty + def my_abstract_property(self): + ... + + This defines a read-only property; you can also define a read-write + abstract property using the 'long' form of property declaration: + + class C(metaclass=ABCMeta): + def getx(self): ... + def setx(self, value): ... + x = abstractproperty(getx, setx) + + 'abstractproperty' is deprecated. Use 'property' with 'abstractmethod' + instead. + """ + + __isabstractmethod__ = True + + +class ABCMeta(type): + + """Metaclass for defining Abstract Base Classes (ABCs). + + Use this metaclass to create an ABC. An ABC can be subclassed + directly, and then acts as a mix-in class. You can also register + unrelated concrete classes (even built-in classes) and unrelated + ABCs as 'virtual subclasses' -- these and their descendants will + be considered subclasses of the registering ABC by the built-in + issubclass() function, but the registering ABC won't show up in + their MRO (Method Resolution Order) nor will method + implementations defined by the registering ABC be callable (not + even via super()). + + """ + + # A global counter that is incremented each time a class is + # registered as a virtual subclass of anything. It forces the + # negative cache to be cleared before its next use. + _abc_invalidation_counter = 0 + + def __new__(mcls, name, bases, namespace): + cls = super().__new__(mcls, name, bases, namespace) + # Compute set of abstract method names + abstracts = {name + for name, value in namespace.items() + if getattr(value, "__isabstractmethod__", False)} + for base in bases: + for name in getattr(base, "__abstractmethods__", set()): + value = getattr(cls, name, None) + if getattr(value, "__isabstractmethod__", False): + abstracts.add(name) + cls.__abstractmethods__ = frozenset(abstracts) + # Set up inheritance registry + cls._abc_registry = WeakSet() + cls._abc_cache = WeakSet() + cls._abc_negative_cache = WeakSet() + cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter + return cls + + def register(cls, subclass): + """Register a virtual subclass of an ABC. + + Returns the subclass, to allow usage as a class decorator. + """ + if not isinstance(subclass, type): + raise TypeError("Can only register classes") + if issubclass(subclass, cls): + return subclass # Already a subclass + # Subtle: test for cycles *after* testing for "already a subclass"; + # this means we allow X.register(X) and interpret it as a no-op. + if issubclass(cls, subclass): + # This would create a cycle, which is bad for the algorithm below + raise RuntimeError("Refusing to create an inheritance cycle") + cls._abc_registry.add(subclass) + ABCMeta._abc_invalidation_counter += 1 # Invalidate negative cache + return subclass + + def _dump_registry(cls, file=None): + """Debug helper to print the ABC registry.""" + print("Class: %s.%s" % (cls.__module__, cls.__name__), file=file) + print("Inv.counter: %s" % ABCMeta._abc_invalidation_counter, file=file) + for name in sorted(cls.__dict__.keys()): + if name.startswith("_abc_"): + value = getattr(cls, name) + print("%s: %r" % (name, value), file=file) + + def __instancecheck__(cls, instance): + """Override for isinstance(instance, cls).""" + # Inline the cache checking + subclass = instance.__class__ + if subclass in cls._abc_cache: + return True + subtype = type(instance) + if subtype is subclass: + if (cls._abc_negative_cache_version == + ABCMeta._abc_invalidation_counter and + subclass in cls._abc_negative_cache): + return False + # Fall back to the subclass check. + return cls.__subclasscheck__(subclass) + return any(cls.__subclasscheck__(c) for c in {subclass, subtype}) + + def __subclasscheck__(cls, subclass): + """Override for issubclass(subclass, cls).""" + # Check cache + if subclass in cls._abc_cache: + return True + # Check negative cache; may have to invalidate + if cls._abc_negative_cache_version < ABCMeta._abc_invalidation_counter: + # Invalidate the negative cache + cls._abc_negative_cache = WeakSet() + cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter + elif subclass in cls._abc_negative_cache: + return False + # Check the subclass hook + ok = cls.__subclasshook__(subclass) + if ok is not NotImplemented: + assert isinstance(ok, bool) + if ok: + cls._abc_cache.add(subclass) + else: + cls._abc_negative_cache.add(subclass) + return ok + # Check if it's a direct subclass + if cls in getattr(subclass, '__mro__', ()): + cls._abc_cache.add(subclass) + return True + # Check if it's a subclass of a registered class (recursive) + for rcls in cls._abc_registry: + if issubclass(subclass, rcls): + cls._abc_cache.add(subclass) + return True + # Check if it's a subclass of a subclass (recursive) + for scls in cls.__subclasses__(): + if issubclass(subclass, scls): + cls._abc_cache.add(subclass) + return True + # No dice; update negative cache + cls._abc_negative_cache.add(subclass) + return False |