yorm.wrapped() - Code Metrics - Inspection of "Update project structure" - jacebrowning/yorm - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — develop ( b517c8...2e9112 )

by Jace

created 2016-02-13 02:11 UTC

yorm.wrapped() A

↳ Parent: yorm.prevent_recursion()

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	7
CRAP Score	2

Metric	Value
cc	2
dl	0
loc	8
ccs	7
cts	7
cp	1
crap	2
rs	9.4285

"""Core YAML mapping functionality."""

import os
import abc
import functools
from pprint import pformat

from . import common, exceptions, settings
from .bases import Container

MAPPER = '__mapper__'

log = common.logger(__name__)


def get_mapper(obj):
    """Get `Mapper` instance attached to an object."""
    return getattr(obj, MAPPER, None)


def set_mapper(obj, path, attrs, auto=True, root=None):
    """Create and attach a `Mapper` instance to an object."""
    mapper = Mapper(obj, path, attrs, auto=auto, root=root)
    setattr(obj, MAPPER, mapper)
    return mapper


def file_required(create=False):
    """Decorator for methods that require the file to exist.

    :param create: boolean or the method to decorate

    """
    def decorator(method):

        @functools.wraps(method)
        def wrapped(self, *args, **kwargs):
            if not self.path:
                return None
            if not self.exists and self.auto:
                if create is True and not self.deleted:
                    self.create()
                else:
                    msg = "Cannot access deleted: {}".format(self.path)
                    raise exceptions.FileDeletedError(msg)

            return method(self, *args, **kwargs)

        return wrapped

    if callable(create):
        return decorator(create)
    else:
        return decorator


def prevent_recursion(method):
    """Decorator to prevent indirect recursive calls."""

    # pylint: disable=protected-access

    @functools.wraps(method)
    def wrapped(self, *args, **kwargs):
        if self._activity:
            return
        self._activity = True
        result = method(self, *args, **kwargs)
        self._activity = False
        return result

    return wrapped


def prefix(obj):
    """Prefix a string with a fake designator if enabled."""
    fake = "(fake) " if settings.fake else ""
    name = obj if isinstance(obj, str) else "'{}'".format(obj)
    return fake + name


class BaseHelper(metaclass=abc.ABCMeta):
    """Utility class to map attributes to text files.

    To start mapping attributes to a file:

        create -> [empty] -> FILE

    When getting an attribute:

        FILE -> read -> [text] -> load -> [dict] -> fetch -> ATTRIBUTES

    When setting an attribute:

        ATTRIBUTES -> store -> [dict] -> dump -> [text] -> write -> FILE

    After the mapped file is no longer needed:

        delete -> [null] -> FILE

    """

    def __init__(self, path, auto=True):
        self.path = path
        self.auto = auto
        self.auto_store = False
        self.exists = self.path and os.path.isfile(self.path)
        self.deleted = False
        self._activity = False
        self._timestamp = 0
        self._fake = ""

    def __str__(self):
        return str(self.path)

    @property
    def text(self):
        """Get file contents."""
        log.info("Getting contents of %s...", prefix(self))
        if settings.fake:
            text = self._fake
        else:
            text = self._read()
        log.trace("Text read: \n%s", text[:-1])
        return text

    @text.setter
    def text(self, text):
        """Set file contents."""
        log.info("Setting contents of %s...", prefix(self))
        if settings.fake:
            self._fake = text
        else:
            self._write(text)
        log.trace("Text wrote: \n%s", text[:-1])
        self.modified = True

    @property
    def modified(self):
        """Determine if the file has been modified."""
        if settings.fake:
            changes = self._timestamp is not None
            return changes
        elif not self.exists:
            return True
        else:
            was = self._timestamp
            now = common.stamp(self.path)
            return was != now

    @modified.setter
    def modified(self, changes):
        """Mark the file as modified if there are changes."""
        if changes:
            log.debug("Marked %s as modified", prefix(self))
            self._timestamp = 0
        else:
            if settings.fake or self.path is None:
                self._timestamp = None
            else:
                self._timestamp = common.stamp(self.path)
            log.debug("Marked %s as unmodified", prefix(self))

    @property
    def ext(self):
        if '.' in self.path:
            return self.path.split('.')[-1]
        else:
            return 'yml'

    def create(self, obj):
        """Create a new file for the object."""
        log.info("Creating %s for %r...", prefix(self), obj)
        if self.exists:
            log.warning("Already created: %s", self)
            return
        if not settings.fake:
            common.create_dirname(self.path)
            common.touch(self.path)
        self.exists = True
        self.deleted = False

    @file_required
    @prevent_recursion
    def fetch(self, obj, attrs):
        """Update the object's mapped attributes from its file."""
        log.info("Fetching %r from %s...", obj, prefix(self))

        # Parse data from file
        text = self._read()
        data = self._load(text=text, path=self.path, ext=self.ext)
        log.trace("Loaded data: \n%s", pformat(data))

        # Update all attributes
        attrs2 = attrs.copy()
        for name, data in data.items():
            attrs2.pop(name, None)

            # Find a matching converter
            try:
                converter = attrs[name]
            except KeyError:
                # TODO: determine if runtime import is the best way to avoid
                # cyclic import
                from .types import match
                converter = match(name, data)
                attrs[name] = converter

            # Convert the loaded attribute
            attr = getattr(obj, name, None)
            if all((isinstance(attr, converter),
                    issubclass(converter, Container))):
                attr.update_value(data)
            else:
                attr = converter.to_value(data)
                setattr(obj, name, attr)
            self._remap(attr)
            log.trace("Value fetched: %s = %r", name, attr)

        # Add missing attributes
        for name, converter in attrs2.items():
            if not hasattr(obj, name):
                value = converter.to_value(None)
                msg = "Fetched default value for missing attribute: %s = %r"
                log.warning(msg, name, value)
                setattr(obj, name, value)

        # Set meta attributes
        self.modified = False

    @file_required(create=True)
    @prevent_recursion
    def store(self, obj, attrs):
        """Format and save the object's mapped attributes to its file."""
        log.info("Storing %r to %s...", obj, prefix(self))

        # Format the data items
        data = {}
        for name, converter in attrs.items():
            try:
                value = getattr(obj, name)
            except AttributeError:
                value = None
                msg = "Storing default data for missing attribute '%s'..."
                log.warning(msg, name)

            data2 = converter.to_data(value)

            log.trace("Data to store: %s = %r", name, data2)
            data[name] = data2

        # Dump data to file
        text = self._dump(data=data, ext=self.ext)
        self._write(text)

        # Set meta attributes
        self.modified = True
        self.auto_store = self.auto

    def delete(self):
        """Delete the object's file from the file system."""
        if self.exists:
            log.info("Deleting %s...", prefix(self))
            if not settings.fake:
                common.delete(self.path)
        else:
            log.warning("Already deleted: %s", self)
        self.exists = False
        self.deleted = True

    @file_required
    def _read(self):
        """Read text from the object's file.

        :param path: path to a text file

        :return: contexts of text file

        """
        if settings.fake:
            return self._fake
        elif not self.exists:
            return ""
        else:
            return common.read_text(self.path)

    @file_required
    def _write(self, text):
        """Write text to the object's file.

        :param text: text to write to a file
        :param path: path to the file

        """
        if settings.fake:
            self._fake = text
        else:
            common.write_text(text, self.path)

    @abc.abstractstaticmethod
    def _load(text, path, ext):  # pragma: no cover (abstract method)
        """Parsed data from text.

        :param text: text read from a file
        :param path: path to the file (for displaying errors)

        :return: dictionary of parsed data

        """
        raise NotImplementedError

    @abc.abstractstaticmethod
    def _dump(data, ext):  # pragma: no cover (abstract method)
        """Dump data to text.

        :param data: dictionary of data

        :return: text to write to a file

        """
        raise NotImplementedError

    def _remap(self, obj):
        """Restore mapping on nested attributes."""
        if isinstance(obj, Container):
            set_mapper(obj, None, common.attrs[obj.__class__], root=self)
            if isinstance(obj, dict):
                for obj2 in obj.values():
                    self._remap(obj2)
            else:
                assert isinstance(obj, list)
                for obj2 in obj:
                    self._remap(obj2)


class Helper(BaseHelper):
    """Utility class to map attributes to YAML files."""

    @staticmethod
    def _load(text, path, ext):
        """Load YAML data from text.

        :param text: text read from a file
        :param path: path to the file (for displaying errors)

        :return: dictionary of YAML data

        """
        return common.load_file(text, path, ext)

    @staticmethod
    def _dump(data, ext):
        """Dump YAML data to text.

        :param data: dictionary of YAML data

        :return: text to write to a file

        """
        return common.dump_file(data, ext)


class Mapper(Helper):
    """Maps an object's attribute to YAML files."""

    # TODO: rewrite this class to use composition
    # pylint: disable=arguments-differ

    def __init__(self, obj, path, attrs, auto=True, root=None):
        super().__init__(path, auto=auto)
        self.obj = obj
        self.attrs = attrs
        self.root = root

    def create(self):
        super().create(self.obj)

    def fetch(self):
        if self.root and self.root.auto and not self._activity:
            self._activity = True
            self.root.fetch()
            self._activity = False
        super().fetch(self.obj, self.attrs)

    def store(self):
        if self.root and self.root.auto and not self._activity:
            self._activity = True
            self.root.store()
            self._activity = False
        super().store(self.obj, self.attrs)


1		"""Core YAML mapping functionality."""
2
3	1	import os
4	1	import abc
5	1	import functools
6	1	from pprint import pformat
7
8	1	from . import common, exceptions, settings
9	1	from .bases import Container
10
11	1	MAPPER = '__mapper__'
12
13	1	log = common.logger(__name__)
14
15
16	1	def get_mapper(obj):
17		"""Get `Mapper` instance attached to an object."""
18	1	return getattr(obj, MAPPER, None)
19
20
21	1	def set_mapper(obj, path, attrs, auto=True, root=None):
22		"""Create and attach a `Mapper` instance to an object."""
23	1	mapper = Mapper(obj, path, attrs, auto=auto, root=root)
24	1	setattr(obj, MAPPER, mapper)
25	1	return mapper
26
27
28	1	def file_required(create=False):
29		"""Decorator for methods that require the file to exist.
30
31		:param create: boolean or the method to decorate
32
33		"""
34	1	def decorator(method):
35
36	1	@functools.wraps(method)
37		def wrapped(self, args, *kwargs):
38	1	if not self.path:
39	1	return None
40	1	if not self.exists and self.auto:
41	1	if create is True and not self.deleted:
42	1	self.create()
43		else:
44	1	msg = "Cannot access deleted: {}".format(self.path)
45	1	raise exceptions.FileDeletedError(msg)
46
47	1	return method(self, args, *kwargs)
48
49	1	return wrapped
50
51	1	if callable(create):
52	1	return decorator(create)
53		else:
54	1	return decorator
55
56
57	1	def prevent_recursion(method):
58		"""Decorator to prevent indirect recursive calls."""
59
60		# pylint: disable=protected-access
61
62	1	@functools.wraps(method)
63		def wrapped(self, args, *kwargs):
64	1	if self._activity:
65	1	return
66	1	self._activity = True
67	1	result = method(self, args, *kwargs)
68	1	self._activity = False
69	1	return result
70
71	1	return wrapped
72
73
74	1	def prefix(obj):
75		"""Prefix a string with a fake designator if enabled."""
76	1	fake = "(fake) " if settings.fake else ""
77	1	name = obj if isinstance(obj, str) else "'{}'".format(obj)
78	1	return fake + name
79
80
81	1	class BaseHelper(metaclass=abc.ABCMeta):
82		"""Utility class to map attributes to text files.
83
84		To start mapping attributes to a file:
85
86		create -> [empty] -> FILE
87
88		When getting an attribute:
89
90		FILE -> read -> [text] -> load -> [dict] -> fetch -> ATTRIBUTES
91
92		When setting an attribute:
93
94		ATTRIBUTES -> store -> [dict] -> dump -> [text] -> write -> FILE
95
96		After the mapped file is no longer needed:
97
98		delete -> [null] -> FILE
99
100		"""
101
102	1	def __init__(self, path, auto=True):
103	1	self.path = path
104	1	self.auto = auto
105	1	self.auto_store = False
106	1	self.exists = self.path and os.path.isfile(self.path)
107	1	self.deleted = False
108	1	self._activity = False
109	1	self._timestamp = 0
110	1	self._fake = ""
111
112	1	def __str__(self):
113	1	return str(self.path)
114
115	1	@property
116		def text(self):
117		"""Get file contents."""
118	1	log.info("Getting contents of %s...", prefix(self))
119	1	if settings.fake:
120	1	text = self._fake
121		else:
122	1	text = self._read()
123	1	log.trace("Text read: \n%s", text[:-1])
124	1	return text
125
126	1	@text.setter
127		def text(self, text):
128		"""Set file contents."""
129	1	log.info("Setting contents of %s...", prefix(self))
130	1	if settings.fake:
131	1	self._fake = text
132		else:
133	1	self._write(text)
134	1	log.trace("Text wrote: \n%s", text[:-1])
135	1	self.modified = True
136
137	1	@property
138		def modified(self):
139		"""Determine if the file has been modified."""
140	1	if settings.fake:
141	1	changes = self._timestamp is not None
142	1	return changes
143	1	elif not self.exists:
144	1	return True
145		else:
146	1	was = self._timestamp
147	1	now = common.stamp(self.path)
148	1	return was != now
149
150	1	@modified.setter
151		def modified(self, changes):
152		"""Mark the file as modified if there are changes."""
153	1	if changes:
154	1	log.debug("Marked %s as modified", prefix(self))
155	1	self._timestamp = 0
156		else:
157	1	if settings.fake or self.path is None:
158	1	self._timestamp = None
159		else:
160	1	self._timestamp = common.stamp(self.path)
161	1	log.debug("Marked %s as unmodified", prefix(self))
162
163	1	@property
164		def ext(self):
165	1	if '.' in self.path:
166	1	return self.path.split('.')[-1]
167		else:
168	1	return 'yml'
169
170	1	def create(self, obj):
171		"""Create a new file for the object."""
172	1	log.info("Creating %s for %r...", prefix(self), obj)
173	1	if self.exists:
174	1	log.warning("Already created: %s", self)
175	1	return
176	1	if not settings.fake:
177	1	common.create_dirname(self.path)
178	1	common.touch(self.path)
179	1	self.exists = True
180	1	self.deleted = False
181
182	1	@file_required
183	1	@prevent_recursion
184		def fetch(self, obj, attrs):
185		"""Update the object's mapped attributes from its file."""
186	1	log.info("Fetching %r from %s...", obj, prefix(self))
187
188		# Parse data from file
189	1	text = self._read()
190	1	data = self._load(text=text, path=self.path, ext=self.ext)
191	1	log.trace("Loaded data: \n%s", pformat(data))
192
193		# Update all attributes
194	1	attrs2 = attrs.copy()
195	1	for name, data in data.items():
196	1	attrs2.pop(name, None)
197
198		# Find a matching converter
199	1	try:
200	1	converter = attrs[name]
201	1	except KeyError:
202		# TODO: determine if runtime import is the best way to avoid
203		# cyclic import
204	1	from .types import match
205	1	converter = match(name, data)
206	1	attrs[name] = converter
207
208		# Convert the loaded attribute
209	1	attr = getattr(obj, name, None)
210	1	if all((isinstance(attr, converter),
211		issubclass(converter, Container))):
212	1	attr.update_value(data)
213		else:
214	1	attr = converter.to_value(data)
215	1	setattr(obj, name, attr)
216	1	self._remap(attr)
217	1	log.trace("Value fetched: %s = %r", name, attr)
218
219		# Add missing attributes
220	1	for name, converter in attrs2.items():
221	1	if not hasattr(obj, name):
222	1	value = converter.to_value(None)
223	1	msg = "Fetched default value for missing attribute: %s = %r"
224	1	log.warning(msg, name, value)
225	1	setattr(obj, name, value)
226
227		# Set meta attributes
228	1	self.modified = False
229
230	1	@file_required(create=True)
231	1	@prevent_recursion
232		def store(self, obj, attrs):
233		"""Format and save the object's mapped attributes to its file."""
234	1	log.info("Storing %r to %s...", obj, prefix(self))
235
236		# Format the data items
237	1	data = {}
238	1	for name, converter in attrs.items():
239	1	try:
240	1	value = getattr(obj, name)
241	1	except AttributeError:
242	1	value = None
243	1	msg = "Storing default data for missing attribute '%s'..."
244	1	log.warning(msg, name)
245
246	1	data2 = converter.to_data(value)
247
248	1	log.trace("Data to store: %s = %r", name, data2)
249	1	data[name] = data2
250
251		# Dump data to file
252	1	text = self._dump(data=data, ext=self.ext)
253	1	self._write(text)
254
255		# Set meta attributes
256	1	self.modified = True
257	1	self.auto_store = self.auto
258
259	1	def delete(self):
260		"""Delete the object's file from the file system."""
261	1	if self.exists:
262	1	log.info("Deleting %s...", prefix(self))
263	1	if not settings.fake:
264	1	common.delete(self.path)
265		else:
266	1	log.warning("Already deleted: %s", self)
267	1	self.exists = False
268	1	self.deleted = True
269
270	1	@file_required
271		def _read(self):
272		"""Read text from the object's file.
273
274		:param path: path to a text file
275
276		:return: contexts of text file
277
278		"""
279	1	if settings.fake:
280	1	return self._fake
281	1	elif not self.exists:
282	1	return ""
283		else:
284	1	return common.read_text(self.path)
285
286	1	@file_required
287		def _write(self, text):
288		"""Write text to the object's file.
289
290		:param text: text to write to a file
291		:param path: path to the file
292
293		"""
294	1	if settings.fake:
295	1	self._fake = text
296		else:
297	1	common.write_text(text, self.path)
298
299	1	@abc.abstractstaticmethod
300		def _load(text, path, ext): # pragma: no cover (abstract method)
301		"""Parsed data from text.
302
303		:param text: text read from a file
304		:param path: path to the file (for displaying errors)
305
306		:return: dictionary of parsed data
307
308		"""
309		raise NotImplementedError
310
311	1	@abc.abstractstaticmethod
312		def _dump(data, ext): # pragma: no cover (abstract method)
313		"""Dump data to text.
314
315		:param data: dictionary of data
316
317		:return: text to write to a file
318
319		"""
320		raise NotImplementedError
321
322	1	def _remap(self, obj):
323		"""Restore mapping on nested attributes."""
324	1	if isinstance(obj, Container):
325	1	set_mapper(obj, None, common.attrs[obj.__class__], root=self)
326	1	if isinstance(obj, dict):
327	1	for obj2 in obj.values():
328	1	self._remap(obj2)
329		else:
330	1	assert isinstance(obj, list)
331	1	for obj2 in obj:
332	1	self._remap(obj2)
333
334
335	1	class Helper(BaseHelper):
336		"""Utility class to map attributes to YAML files."""
337
338	1	@staticmethod
339		def _load(text, path, ext):
340		"""Load YAML data from text.
341
342		:param text: text read from a file
343		:param path: path to the file (for displaying errors)
344
345		:return: dictionary of YAML data
346
347		"""
348	1	return common.load_file(text, path, ext)
349
350	1	@staticmethod
351		def _dump(data, ext):
352		"""Dump YAML data to text.
353
354		:param data: dictionary of YAML data
355
356		:return: text to write to a file
357
358		"""
359	1	return common.dump_file(data, ext)
360
361
362	1	class Mapper(Helper):
363		"""Maps an object's attribute to YAML files."""
364
365		# TODO: rewrite this class to use composition
366		# pylint: disable=arguments-differ
367
368	1	def __init__(self, obj, path, attrs, auto=True, root=None):
369	1	super().__init__(path, auto=auto)
370	1	self.obj = obj
371	1	self.attrs = attrs
372	1	self.root = root
373
374	1	def create(self):
375	1	super().create(self.obj)
376
377	1	def fetch(self):
378	1	if self.root and self.root.auto and not self._activity:
379	1	self._activity = True
380	1	self.root.fetch()
381	1	self._activity = False
382	1	super().fetch(self.obj, self.attrs)
383
384	1	def store(self):
385	1	if self.root and self.root.auto and not self._activity:
386	1	self._activity = True
387	1	self.root.store()
388	1	self._activity = False
389		super().store(self.obj, self.attrs)
390

jacebrowning / yorm

Push — develop ( b517c8...2e9112 )

yorm.wrapped() A

Complexity

Size

Duplication

Code Coverage

Duplication Side-by-Side

Filter issues like