coalib.misc.decorator() - Code Metrics - Inspection of "coalib: Add flag -o to coala-json" - coala-analyzer/coala - Measure and Improve Code Quality continuously with Scrutinizer

Failed Conditions

Pull Request — master (#1311)

by Sudheesh

created 2016-02-20 14:36 UTC

coalib.misc.decorator() B

↳ Parent: coalib.misc.generate_repr()

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Metric	Value
cc	5
dl	0
loc	3
rs	8.5454

import inspect
from functools import total_ordering


def yield_once(iterator):
    """
    Decorator to make an iterator yield each result only once.

    :param iterator: Any iterator
    :return:         An iterator that yields every result only once at most.
    """
    def yield_once_generator(*args, **kwargs):
        yielded = []
        for item in iterator(*args, **kwargs):
            if item in yielded:
                pass
            else:
                yielded.append(item)
                yield item

    return yield_once_generator


def _to_list(var):
    """
    Make variable to list.

    :param var: variable of any type
    :return:    list
    """
    if isinstance(var, list):
        return var
    elif var is None:
        return []
    elif isinstance(var, str) or isinstance(var, dict):
        # We dont want to make a list out of those via the default constructor
        return [var]
    else:
        try:
            return list(var)
        except TypeError:
            return [var]


def arguments_to_lists(function):
    """
    Decorator for a function that converts all arguments to lists.

    :param function: target function
    :return:         target function with only lists as parameters
    """
    def l_function(*args, **kwargs):
        l_args = [_to_list(arg) for arg in args]
        l_kwargs = {}

        for key, value in kwargs.items():
            l_kwargs[key] = _to_list(value)
        return function(*l_args, **l_kwargs)

    return l_function


def _get_member(obj, member):
    # If not found, pass AttributeError to invoking function.
    attribute = getattr(obj, member)

    if callable(attribute) and hasattr(attribute, "__self__"):
        # If the value is a bound method, invoke it like a getter and return
        # its value.
        try:
            return attribute()
        except TypeError:
            # Don't use repr() to display the member more accurately, because
            # invoking repr() on a bound method prints in this format:
            # <bound method CLASS.METHOD of **repr(instance)**>
            # This invokes repr() recursively.
            raise TypeError("Given bound method '" + member + "' must be "
                            "callable like a getter, taking no arguments.")
    else:
        # Otherwise it's a member variable or property (or any other attribute
        # that holds a value).
        return attribute


def _construct_repr_string(obj, members):
    # The passed entries have format (member-name, repr-function).
    values = ", ".join(member + "=" + func(_get_member(obj, member))
                       for member, func in members)
    return ("<" + type(obj).__name__ + " object(" + values + ") at "
            + hex(id(obj)) + ">")


def get_public_members(obj):
    """
    Retrieves a list of member-like objects (members or properties) that are
    publically exposed.

    :param obj: The object to probe.
    :return:    A list of strings.
    """
    return {attr: getattr(obj, attr) for attr in dir(obj)
            if not attr.startswith("_")
            and not hasattr(getattr(obj, attr), '__call__')}


def generate_repr(*members):
    """
    Decorator that binds an auto-generated `__repr__()` function to a class.

    The generated `__repr__()` function prints in following format:
    <ClassName object(field1=1, field2='A string', field3=[1, 2, 3]) at 0xAAAA>

    Note that this decorator modifies the given class in place!

    :param members:         An iterable of member names to include into the
                            representation-string. Providing no members yields
                            to inclusion of all member variables and properties
                            in alphabetical order (except if they start with an
                            underscore).

                            To control the representation of each member, you
                            can also pass a tuple where the first element
                            contains the member to print and the second one the
                            representation function (which defaults to the
                            built-in `repr()`). Using None as representation
                            function is the same as using `repr()`.

                            Supported members are fields/variables, properties
                            and getter-like functions (functions that accept no
                            arguments).
    :raises ValueError:     Raised when the passed
                            (member, repr-function)-tuples have not a length of
                            2.
    :raises AttributeError: Raised when a given member/attribute was not found
                            in class.
    :raises TypeError:      Raised when a provided member is a bound method
                            that is not a getter-like function (means it must
                            accept no parameters).
    :return:                The class armed with an auto-generated __repr__
                            function.
    """
    def decorator(cls):
        cls.__repr__ = __repr__
        return cls

    if members:
        # Prepare members list.
        members_to_print = list(members)
        for i, member in enumerate(members_to_print):
            if isinstance(member, tuple):
                # Check tuple dimensions.
                length = len(member)
                if length == 2:
                    members_to_print[i] = (member[0],
                                           member[1] if member[1] else repr)
                else:
                    raise ValueError("Passed tuple " + repr(member) +
                                     " needs to be 2-dimensional, but has " +
                                     str(length) + " dimensions.")
            else:
                members_to_print[i] = (member, repr)

        def __repr__(self):
            return _construct_repr_string(self, members_to_print)
    else:
        def __repr__(self):
            # Need to fetch member variables every time since they are unknown
            # until class instantation.
            members_to_print = get_public_members(self)

            member_repr_list = ((member, repr) for member in
                                sorted(members_to_print, key=str.lower))

            return _construct_repr_string(self, member_repr_list)

    return decorator


def generate_eq(*members):
    """
    Decorator that generates equality and inequality operators for the
    decorated class. The given members as well as the type of self and other
    will be taken into account.

    Note that this decorator modifies the given class in place!

    :param members: A list of members to compare for equality.
    """
    def decorator(cls):
        def eq(self, other):
            if type(other) is not type(self):
                return False

            return all(getattr(self, member) == getattr(other, member)
                       for member in members)

        def ne(self, other):
            return not eq(self, other)

        cls.__eq__ = eq
        cls.__ne__ = ne
        return cls

    return decorator


def generate_ordering(*members):
    """
    Decorator that generates ordering operators for the decorated class based
    on the given member names. All ordering except equality functions will
    raise a TypeError when a comparison with an unrelated class is attempted.
    (Comparisons with child classes will thus work fine with the capabilities
    of the base class as python will choose the base classes comparison
    operator in that case.)

    Note that this decorator modifies the given class in place!

    :param members: A list of members to compare, ordered from high priority to
                    low. I.e. if the first member is equal the second will be
                    taken for comparison and so on. If a member is None it is
                    considered smaller than any other value except None.
    """
    def decorator(cls):
        def lt(self, other):
            if not isinstance(other, cls):
                raise TypeError("Comparison with unrelated classes is "
                                "unsupported.")

            for member in members:
                if getattr(self, member) == getattr(other, member):
                    continue

                if (
                        getattr(self, member) is None or
                        getattr(other, member) is None):
                    return getattr(self, member) is None

                return getattr(self, member) < getattr(other, member)

            return False

        cls.__lt__ = lt
        return total_ordering(generate_eq(*members)(cls))

    return decorator


def _assert_right_type(value, types, argname):
    if isinstance(types, type) or types is None:
        types = (types,)

    for typ in types:
        if value == typ or (isinstance(typ, type) and isinstance(value, typ)):
            return

    raise TypeError("{} must be an instance of one of {} (provided value: "
                    "{})".format(argname, types, repr(value)))


def enforce_signature(function):
    """
    Enforces the signature of the function by throwing TypeError's if invalid
    arguments are provided. The return value is not checked.

    You can annotate any parameter of your function with the desired type or a
    tuple of allowed types. If you annotate the function with a value, this
    value only will be allowed (useful especially for None). Example:

    >>> @enforce_signature
    ... def test(arg: bool, another: (int, None)):
    ...     pass
    ...
    >>> test(True, 5)
    >>> test(True, None)

    Any string value for any parameter e.g. would then trigger a TypeError.

    :param function: The function to check.
    """
    argspec = inspect.getfullargspec(function)
    annotations = argspec.annotations
    argnames = argspec.args

    unnamed_annotations = {}
    for i, arg in enumerate(argnames):
        if arg in annotations:
            unnamed_annotations[i] = (annotations[arg], arg)

    def decorated(*args, **kwargs):
        for i, annotation in unnamed_annotations.items():
            if i < len(args):
                _assert_right_type(args[i], annotation[0], annotation[1])

        for argname, argval in kwargs.items():
            if argname in annotations:
                _assert_right_type(argval, annotations[argname], argname)

        return function(*args, **kwargs)

    return decorated


1			import inspect
2			from functools import total_ordering
3
4
5			def yield_once(iterator):
6			"""
7			Decorator to make an iterator yield each result only once.
8
9			:param iterator: Any iterator
10			:return: An iterator that yields every result only once at most.
11			"""
12			def yield_once_generator(args, *kwargs):
13			yielded = []
14			for item in iterator(args, *kwargs):
15			if item in yielded:
16			pass
17			else:
18			yielded.append(item)
19			yield item
20
21			return yield_once_generator
22
23
24			def _to_list(var):
25			"""
26			Make variable to list.
27
28			:param var: variable of any type
29			:return: list
30			"""
31			if isinstance(var, list):
32			return var
33			elif var is None:
34			return []
35			elif isinstance(var, str) or isinstance(var, dict):
36			# We dont want to make a list out of those via the default constructor
37			return [var]
38			else:
39			try:
40			return list(var)
41			except TypeError:
42			return [var]
43
44
45			def arguments_to_lists(function):
46			"""
47			Decorator for a function that converts all arguments to lists.
48
49			:param function: target function
50			:return: target function with only lists as parameters
51			"""
52			def l_function(args, *kwargs):
53			l_args = [_to_list(arg) for arg in args]
54			l_kwargs = {}
55
56			for key, value in kwargs.items():
57			l_kwargs[key] = _to_list(value)
58			return function(l_args, *l_kwargs)
59
60			return l_function
61
62
63			def _get_member(obj, member):
64			# If not found, pass AttributeError to invoking function.
65			attribute = getattr(obj, member)
66
67			if callable(attribute) and hasattr(attribute, "__self__"):
68			# If the value is a bound method, invoke it like a getter and return
69			# its value.
70			try:
71			return attribute()
72			except TypeError:
73			# Don't use repr() to display the member more accurately, because
74			# invoking repr() on a bound method prints in this format:
75			# <bound method CLASS.METHOD of repr(instance)>
76			# This invokes repr() recursively.
77			raise TypeError("Given bound method '" + member + "' must be "
78			"callable like a getter, taking no arguments.")
79			else:
80			# Otherwise it's a member variable or property (or any other attribute
81			# that holds a value).
82			return attribute
83
84
85			def _construct_repr_string(obj, members):
86			# The passed entries have format (member-name, repr-function).
87			values = ", ".join(member + "=" + func(_get_member(obj, member))
88			for member, func in members)
89			return ("<" + type(obj).__name__ + " object(" + values + ") at "
90			+ hex(id(obj)) + ">")
91
92
93			def get_public_members(obj):
94			"""
95			Retrieves a list of member-like objects (members or properties) that are
96			publically exposed.
97
98			:param obj: The object to probe.
99			:return: A list of strings.
100			"""
101			return {attr: getattr(obj, attr) for attr in dir(obj)
102			if not attr.startswith("_")
103			and not hasattr(getattr(obj, attr), '__call__')}
104
105
106			def generate_repr(*members):
107			"""
108			Decorator that binds an auto-generated `__repr__()` function to a class.
109
110			The generated `__repr__()` function prints in following format:
111			<ClassName object(field1=1, field2='A string', field3=[1, 2, 3]) at 0xAAAA>
112
113			Note that this decorator modifies the given class in place!
114
115			:param members: An iterable of member names to include into the
116			representation-string. Providing no members yields
117			to inclusion of all member variables and properties
118			in alphabetical order (except if they start with an
119			underscore).
120
121			To control the representation of each member, you
122			can also pass a tuple where the first element
123			contains the member to print and the second one the
124			representation function (which defaults to the
125			built-in `repr()`). Using None as representation
126			function is the same as using `repr()`.
127
128			Supported members are fields/variables, properties
129			and getter-like functions (functions that accept no
130			arguments).
131			:raises ValueError: Raised when the passed
132			(member, repr-function)-tuples have not a length of
133			2.
134			:raises AttributeError: Raised when a given member/attribute was not found
135			in class.
136			:raises TypeError: Raised when a provided member is a bound method
137			that is not a getter-like function (means it must
138			accept no parameters).
139			:return: The class armed with an auto-generated __repr__
140			function.
141			"""
142			def decorator(cls):
143			cls.__repr__ = __repr__
144			return cls
145
146			if members:
147			# Prepare members list.
148			members_to_print = list(members)
149			for i, member in enumerate(members_to_print):
150			if isinstance(member, tuple):
151			# Check tuple dimensions.
152			length = len(member)
153			if length == 2:
154			members_to_print[i] = (member[0],
155			member[1] if member[1] else repr)
156			else:
157			raise ValueError("Passed tuple " + repr(member) +
158			" needs to be 2-dimensional, but has " +
159			str(length) + " dimensions.")
160			else:
161			members_to_print[i] = (member, repr)
162
163			def __repr__(self):
164			return _construct_repr_string(self, members_to_print)
165			else:
166			def __repr__(self):
167			# Need to fetch member variables every time since they are unknown
168			# until class instantation.
169			members_to_print = get_public_members(self)
170
171			member_repr_list = ((member, repr) for member in
172			sorted(members_to_print, key=str.lower))
173
174			return _construct_repr_string(self, member_repr_list)
175
176			return decorator
177
178
179			def generate_eq(*members):
180			"""
181			Decorator that generates equality and inequality operators for the
182			decorated class. The given members as well as the type of self and other
183			will be taken into account.
184
185			Note that this decorator modifies the given class in place!
186
187			:param members: A list of members to compare for equality.
188			"""
189			def decorator(cls):
190			def eq(self, other):
191			if type(other) is not type(self):
192			return False
193
194			return all(getattr(self, member) == getattr(other, member)
195			for member in members)
196
197			def ne(self, other):
198			return not eq(self, other)
199
200			cls.__eq__ = eq
201			cls.__ne__ = ne
202			return cls
203
204			return decorator
205
206
207			def generate_ordering(*members):
208			"""
209			Decorator that generates ordering operators for the decorated class based
210			on the given member names. All ordering except equality functions will
211			raise a TypeError when a comparison with an unrelated class is attempted.
212			(Comparisons with child classes will thus work fine with the capabilities
213			of the base class as python will choose the base classes comparison
214			operator in that case.)
215
216			Note that this decorator modifies the given class in place!
217
218			:param members: A list of members to compare, ordered from high priority to
219			low. I.e. if the first member is equal the second will be
220			taken for comparison and so on. If a member is None it is
221			considered smaller than any other value except None.
222			"""
223			def decorator(cls):
224			def lt(self, other):
225			if not isinstance(other, cls):
226			raise TypeError("Comparison with unrelated classes is "
227			"unsupported.")
228
229			for member in members:
230			if getattr(self, member) == getattr(other, member):
231			continue
232
233			if (
234			getattr(self, member) is None or
235			getattr(other, member) is None):
236			return getattr(self, member) is None
237
238			return getattr(self, member) < getattr(other, member)
239
240			return False
241
242			cls.__lt__ = lt
243			return total_ordering(generate_eq(*members)(cls))
244
245			return decorator
246
247
248			def _assert_right_type(value, types, argname):
249			if isinstance(types, type) or types is None:
250			types = (types,)
251
252			for typ in types:
253			if value == typ or (isinstance(typ, type) and isinstance(value, typ)):
254			return
255
256			raise TypeError("{} must be an instance of one of {} (provided value: "
257			"{})".format(argname, types, repr(value)))
258
259
260			def enforce_signature(function):
261			"""
262			Enforces the signature of the function by throwing TypeError's if invalid
263			arguments are provided. The return value is not checked.
264
265			You can annotate any parameter of your function with the desired type or a
266			tuple of allowed types. If you annotate the function with a value, this
267			value only will be allowed (useful especially for None). Example:
268
269			>>> @enforce_signature
270			... def test(arg: bool, another: (int, None)):
271			... pass
272			...
273			>>> test(True, 5)
274			>>> test(True, None)
275
276			Any string value for any parameter e.g. would then trigger a TypeError.
277
278			:param function: The function to check.
279			"""
280			argspec = inspect.getfullargspec(function)
281			annotations = argspec.annotations
282			argnames = argspec.args
283
284			unnamed_annotations = {}
285			for i, arg in enumerate(argnames):
286			if arg in annotations:
287			unnamed_annotations[i] = (annotations[arg], arg)
288
289			def decorated(args, *kwargs):
290			for i, annotation in unnamed_annotations.items():
291			if i < len(args):
292			_assert_right_type(args[i], annotation[0], annotation[1])
293
294			for argname, argval in kwargs.items():
295			if argname in annotations:
296			_assert_right_type(argval, annotations[argname], argname)
297
298			return function(args, *kwargs)
299
300			return decorated
301

coala-analyzer / coala

Pull Request — master (#1311)

coalib.misc.decorator() B

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