zipline.utils.Sentinel - Code Metrics - Inspection of "BUG: fix issues with sentinel" - quantopian/zipline - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#872)

unknown

created 2015-11-24 21:03 UTC

zipline.utils.Sentinel A

↳ Parent: zipline.utils.sentinel()

Complexity

Total Complexity

Size/Duplication

Total Lines	20
Duplicated Lines	0 %

Metric	Value
dl	0
loc	20
rs	10
wmc	5

"""
Construction of sentinel objects.

Sentinel objects are used when you only care to check for object identity.
"""
import sys


def sentinel(name, doc=None):
    try:
        value = sentinel._cache[name]  # memoized
    except KeyError:
        pass
    else:
        if doc == value.__doc__:
            return value

        raise ValueError(
            'attempted to create sentinel with a used name and a different'
            ' docstring: %r\noriginal docstring:\n%s' % (name, value.__doc__),
        )

    @object.__new__   # bind a single instance to the name 'Sentinel'
    class Sentinel(object):
        __doc__ = doc
        __slots__ = ('__weakref__',)
        __name__ = name

        def __new__(cls):
            raise TypeError("Can't construct new instances of %r" % name)

        def __repr__(self):
            return 'sentinel(%r)' % name

        def __reduce__(self):
            return sentinel, (name, doc)

        def __deepcopy__(self, _memo):
            return self

        def __copy__(self):
            return self

    cls = type(Sentinel)
    try:
        # traverse up one frame to find the module where this is defined
        cls.__module__ = sys._getframe(1).f_globals['__name__']
    except (AttributeError, ValueError, KeyError):
        # Couldn't get the name from the calling scope, just use None.
        cls.__module__ = None

    sentinel._cache[name] = Sentinel  # cache result
    return Sentinel
sentinel._cache = {}


1			"""
2			Construction of sentinel objects.
3
4			Sentinel objects are used when you only care to check for object identity.
5			"""
6			import sys
7
8
9			def sentinel(name, doc=None):
10			try:
11			value = sentinel._cache[name] # memoized
12			except KeyError:
13			pass
14			else:
15			if doc == value.__doc__:
16			return value
17
18			raise ValueError(
19			'attempted to create sentinel with a used name and a different'
20			' docstring: %r\noriginal docstring:\n%s' % (name, value.__doc__),
21			)
22
23			@object.__new__ # bind a single instance to the name 'Sentinel'
24			class Sentinel(object):
25			__doc__ = doc
26			__slots__ = ('__weakref__',)
27			__name__ = name
28
29			def __new__(cls):
30			raise TypeError("Can't construct new instances of %r" % name)
31
32			def __repr__(self):
33			return 'sentinel(%r)' % name
34
35			def __reduce__(self):
36			return sentinel, (name, doc)
37
38			def __deepcopy__(self, _memo):
39			return self
40
41			def __copy__(self):
42			return self
43
44			cls = type(Sentinel)
45			try:
46			# traverse up one frame to find the module where this is defined
47			cls.__module__ = sys._getframe(1).f_globals['__name__']
48			except (AttributeError, ValueError, KeyError):
49			# Couldn't get the name from the calling scope, just use None.
50			cls.__module__ = None
51
52			sentinel._cache[name] = Sentinel # cache result
53			return Sentinel
54			sentinel._cache = {}
55

quantopian / zipline

Pull Request — master (#872)

zipline.utils.Sentinel A

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