_instantiate() - Code Metrics - Inspection of "[WIP] Implement match()" - jacebrowning/yorm - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — develop (#143)

unknown

created 2017-05-30 20:26 UTC

_instantiate() A

↳ Parent: Project

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	6
CRAP Score	3

Importance

Changes	2
Bugs	0	Features	0

Metric	Value
cc	3
c	2
b	0
f	0
dl	0
loc	8
ccs	6
cts	6
cp	1
crap	3
rs	9.4285

"""Functions to interact with mapped classes and instances."""

import inspect
import logging
import string
import glob
import types
import parse

from . import common, exceptions

log = logging.getLogger(__name__)



def create(class_or_instance, *args, overwrite=False, **kwargs):
    """Create a new mapped object.

    NOTE: Calling this function is unnecessary with 'auto_create' enabled.

    """
    instance = _instantiate(class_or_instance, *args, **kwargs)
    mapper = common.get_mapper(instance, expected=True)

    if mapper.exists and not overwrite:
        msg = "{!r} already exists".format(mapper.path)
        raise exceptions.DuplicateMappingError(msg)

    return load(save(instance))


def find(class_or_instance, *args, create=False, **kwargs):  # pylint: disable=redefined-outer-name

    """Find a matching mapped object or return None."""
    instance = _instantiate(class_or_instance, *args, **kwargs)
    mapper = common.get_mapper(instance, expected=True)

    if mapper.exists:
        return instance
    elif create:
        return save(instance)
    else:
        return None


class GlobFormatter(string.Formatter):
    """
    Uses '*' for all unknown fields
    """

    WILDCARD = object()

    def get_value(self, key, args, kwargs):
        try:
            return super().get_value(key, args, kwargs)
        except (KeyError, IndexError):
            return self.WILDCARD

    def convert_field(self, value, conversion):
        if value is self.WILDCARD:
            return self.WILDCARD
        else:
            return super().convert_field(value, conversion)

    def format_field(self, value, format_spec):
        if value is self.WILDCARD:
            return '*'
        else:
            return super().format_field(value, format_spec)


def _unpack_parsed_fields(pathfields):
class SomeClass:
    def some_method(self):
        """Do x and return foo."""
    return {
        (k[len('self.'):] if k.startswith('self.') else k): v
        for k, v in pathfields.items()
    }


def match(cls_or_path, factory=None, **kwargs):
    """match(class, [callable], ...) -> instance, ...
    match(str, callable, ...) -> instance, ...

    Yield all matching mapped objects. Can be used two ways:
    * With a YORM-decorated class, optionally with a factory callable
    * With a Python 3-style string template and a factory callable

    The factory callable must accept keyuword arguments, extracted from the file
    name merged with those passed to match(). If no factory is given, the class
    itself is used as the factory (same signature).
    """
    if isinstance(cls_or_path, type):
        path_format = ...(cls_or_path)
        if factory is None:
            factory = cls_or_path
    else:
        path_format = cls_or_path
        if factory is None:
            raise TypeError("Factory must be given if a string template is used")

    log.debug((path_format, factory, kwargs))
    gf = GlobFormatter()

    mock = types.SimpleNamespace(**kwargs)

    posix_pattern = gf.format(path_format, self=mock, **kwargs)

    py_pattern = parse.compile(path_format)


    for filename in glob.iglob(posix_pattern, recursive=False):

        pathfields = py_pattern.parse(filename)
        fields = _unpack_parsed_fields(pathfields)
        fields.update(kwargs)
        yield factory(**fields)



def load(instance):
    """Force the loading of a mapped object's file.

    NOTE: Calling this function is unnecessary. It exists for the
        aesthetic purpose of having symmetry between save and load.

    """
    mapper = common.get_mapper(instance, expected=True)

    mapper.load()

    return instance


def save(instance):
    """Save a mapped object to file.

    NOTE: Calling this function is unnecessary with 'auto_save' enabled.

    """
    mapper = common.get_mapper(instance, expected=True)

    if mapper.deleted:
        msg = "{!r} was deleted".format(mapper.path)
        raise exceptions.DeletedFileError(msg)

    if not mapper.exists:
        mapper.create()

    mapper.save()

    return instance


def delete(instance):
    """Delete a mapped object's file."""
    mapper = common.get_mapper(instance, expected=True)

    mapper.delete()

    return None


def _instantiate(class_or_instance, *args, **kwargs):
class SomeClass:
    def some_method(self):
        """Do x and return foo."""
    if inspect.isclass(class_or_instance):
        instance = class_or_instance(*args, **kwargs)
    else:
        assert not args
        instance = class_or_instance

    return instance


1		"""Functions to interact with mapped classes and instances."""
2
3	1	import inspect
4	1	import logging
5		import string
6	1	import glob
7		import types
8	1	import parse
9
10		from . import common, exceptions
11	1
12		log = logging.getLogger(__name__)
		0 ignored issues – show Coding Style Naming introduced 2017-01-24 21:22 UTC by Report Bug Copy Issue Report The name `log` does not conform to the constant naming conventions (`(([A-Z_][A-Z0-9_])\|(__.__))$`). This check looks for invalid names for a range of different identifiers. You can set regular expressions to which the identifiers must conform if the defaults do not match your requirements. If your project includes a Pylint configuration file, the settings contained in that file take precedence. To find out more about Pylint, please refer to their site. Loading history...
13
14
15		def create(class_or_instance, args, overwrite=False, *kwargs):
16		"""Create a new mapped object.
17	1
18	1	NOTE: Calling this function is unnecessary with 'auto_create' enabled.
19
20	1	"""
21	1	instance = _instantiate(class_or_instance, args, *kwargs)
22	1	mapper = common.get_mapper(instance, expected=True)
23
24	1	if mapper.exists and not overwrite:
25		msg = "{!r} already exists".format(mapper.path)
26		raise exceptions.DuplicateMappingError(msg)
27	1
28		return load(save(instance))
29	1
30	1
31		def find(class_or_instance, args, create=False, *kwargs): # pylint: disable=redefined-outer-name
		0 ignored issues – show introduced 2017-01-24 21:22 UTC by Report Bug Copy Issue Report Locally disabling redefined-outer-name (W0621) Loading history...
32	1	"""Find a matching mapped object or return None."""
33	1	instance = _instantiate(class_or_instance, args, *kwargs)
34	1	mapper = common.get_mapper(instance, expected=True)
35	1
36		if mapper.exists:
37	1	return instance
38		elif create:
39		return save(instance)
40	1	else:
41		return None
42	1
43	1
44		class GlobFormatter(string.Formatter):
45		"""
46	1	Uses '*' for all unknown fields
47		"""
48
49		WILDCARD = object()
50
51		def get_value(self, key, args, kwargs):
52		try:
53	1	return super().get_value(key, args, kwargs)
54		except (KeyError, IndexError):
55	1	return self.WILDCARD
56
57	1	def convert_field(self, value, conversion):
58		if value is self.WILDCARD:
59		return self.WILDCARD
60	1	else:
61		return super().convert_field(value, conversion)
62
63		def format_field(self, value, format_spec):
64		if value is self.WILDCARD:
65		return '*'
66	1	else:
67		return super().format_field(value, format_spec)
68	1
69	1
70	1	def _unpack_parsed_fields(pathfields):
		0 ignored issues – show Coding Style introduced 2017-05-30 20:35 UTC by Report Bug Copy Issue Report This function should have a docstring. The coding style of this project requires that you add a docstring to this code element. Below, you find an example for methods: class SomeClass: def some_method(self): """Do x and return foo.""" If you would like to know more about docstrings, we recommend to read PEP-257: Docstring Conventions. Loading history...
71		return {
72	1	(k[len('self.'):] if k.startswith('self.') else k): v
73	1	for k, v in pathfields.items()
74		}
75	1
76
77	1	def match(cls_or_path, factory=None, **kwargs):
78		"""match(class, [callable], ...) -> instance, ...
79		match(str, callable, ...) -> instance, ...
80	1
81		Yield all matching mapped objects. Can be used two ways:
82	1	* With a YORM-decorated class, optionally with a factory callable
83		* With a Python 3-style string template and a factory callable
84	1
85		The factory callable must accept keyuword arguments, extracted from the file
86	1	name merged with those passed to match(). If no factory is given, the class
87		itself is used as the factory (same signature).
88		"""
89	1	if isinstance(cls_or_path, type):
90	1	path_format = ...(cls_or_path)
91	1	if factory is None:
92		factory = cls_or_path
93	1	else:
94	1	path_format = cls_or_path
95		if factory is None:
96	1	raise TypeError("Factory must be given if a string template is used")
97
98		log.debug((path_format, factory, kwargs))
99		gf = GlobFormatter()
		0 ignored issues – show Coding Style Naming introduced 2017-05-30 19:29 UTC by Report Bug Copy Issue Report The name `gf` does not conform to the variable naming conventions (`[a-z_][a-z0-9_]{2,30}$`). This check looks for invalid names for a range of different identifiers. You can set regular expressions to which the identifiers must conform if the defaults do not match your requirements. If your project includes a Pylint configuration file, the settings contained in that file take precedence. To find out more about Pylint, please refer to their site. Loading history...
100		mock = types.SimpleNamespace(**kwargs)
101
102		posix_pattern = gf.format(path_format, self=mock, **kwargs)
		0 ignored issues – show Unused Code introduced 2017-05-30 20:35 UTC by Report Bug Copy Issue Report Argument 'self' passed by position and keyword in method call Loading history...
103		py_pattern = parse.compile(path_format)
		0 ignored issues – show Bug introduced 2017-05-30 20:35 UTC by Report Bug Copy Issue Report The Module `parse` does not seem to have a member named `compile`. This check looks for calls to members that are non-existent. These calls will fail. The member could have been renamed or removed. Loading history...
104
105		for filename in glob.iglob(posix_pattern, recursive=False):
		0 ignored issues – show Bug introduced 2017-05-30 19:29 UTC by Report Bug Copy Issue Report The keyword `recursive` does not seem to exist for the function call. Loading history...
106		pathfields = py_pattern.parse(filename)
107		fields = _unpack_parsed_fields(pathfields)
108		fields.update(kwargs)
109		yield factory(**fields)
		0 ignored issues – show Coding Style introduced 2017-05-30 20:35 UTC by Report Bug Copy Issue Report Usage of `` or `` arguments should usually be done with care. Generally, there is nothing wrong with usage of `` or `**` arguments. For readability of the code base, we suggest to not over-use these language constructs though. For more information, we can recommend this blog post from Ned Batchelder including its comments which also touches this aspect. Loading history...
110
111
112		def load(instance):
113		"""Force the loading of a mapped object's file.
114
115		NOTE: Calling this function is unnecessary. It exists for the
116		aesthetic purpose of having symmetry between save and load.
117
118		"""
119		mapper = common.get_mapper(instance, expected=True)
120
121		mapper.load()
122
123		return instance
124
125
126		def save(instance):
127		"""Save a mapped object to file.
128
129		NOTE: Calling this function is unnecessary with 'auto_save' enabled.
130
131		"""
132		mapper = common.get_mapper(instance, expected=True)
133
134		if mapper.deleted:
135		msg = "{!r} was deleted".format(mapper.path)
136		raise exceptions.DeletedFileError(msg)
137
138		if not mapper.exists:
139		mapper.create()
140
141		mapper.save()
142
143		return instance
144
145
146		def delete(instance):
147		"""Delete a mapped object's file."""
148		mapper = common.get_mapper(instance, expected=True)
149
150		mapper.delete()
151
152		return None
153
154
155		def _instantiate(class_or_instance, args, *kwargs):
		0 ignored issues – show Coding Style introduced 2017-01-24 21:22 UTC by Report Bug Copy Issue Report This function should have a docstring. The coding style of this project requires that you add a docstring to this code element. Below, you find an example for methods: class SomeClass: def some_method(self): """Do x and return foo.""" If you would like to know more about docstrings, we recommend to read PEP-257: Docstring Conventions. Loading history...
156		if inspect.isclass(class_or_instance):
157		instance = class_or_instance(args, *kwargs)
158		else:
159		assert not args
160		instance = class_or_instance
161
162		return instance
163

jacebrowning / yorm

Pull Request — develop (#143)

_instantiate() A

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