Coverage for python/lsst/daf/butler/core/storageClass.py: 45%
357 statements
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1# This file is part of daf_butler.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (http://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This software is dual licensed under the GNU General Public License and also
10# under a 3-clause BSD license. Recipients may choose which of these licenses
11# to use; please see the files gpl-3.0.txt and/or bsd_license.txt,
12# respectively. If you choose the GPL option then the following text applies
13# (but note that there is still no warranty even if you opt for BSD instead):
14#
15# This program is free software: you can redistribute it and/or modify
16# it under the terms of the GNU General Public License as published by
17# the Free Software Foundation, either version 3 of the License, or
18# (at your option) any later version.
19#
20# This program is distributed in the hope that it will be useful,
21# but WITHOUT ANY WARRANTY; without even the implied warranty of
22# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23# GNU General Public License for more details.
24#
25# You should have received a copy of the GNU General Public License
26# along with this program. If not, see <http://www.gnu.org/licenses/>.
28"""Support for Storage Classes."""
30from __future__ import annotations
32__all__ = ("StorageClass", "StorageClassFactory", "StorageClassConfig")
34import builtins
35import itertools
36import logging
37from collections import ChainMap
38from collections.abc import (
39 Callable,
40 Collection,
41 ItemsView,
42 Iterator,
43 KeysView,
44 Mapping,
45 Sequence,
46 Set,
47 ValuesView,
48)
49from typing import Any
51from lsst.utils import doImportType
52from lsst.utils.classes import Singleton
53from lsst.utils.introspection import get_full_type_name
55from .config import Config, ConfigSubset
56from .configSupport import LookupKey
57from .storageClassDelegate import StorageClassDelegate
59log = logging.getLogger(__name__)
62class StorageClassConfig(ConfigSubset):
63 """Configuration class for defining Storage Classes."""
65 component = "storageClasses"
66 defaultConfigFile = "storageClasses.yaml"
69class StorageClass:
70 """Class describing how a label maps to a particular Python type.
72 Parameters
73 ----------
74 name : `str`
75 Name to use for this class.
76 pytype : `type` or `str`
77 Python type (or name of type) to associate with the `StorageClass`
78 components : `dict`, optional
79 `dict` mapping name of a component to another `StorageClass`.
80 derivedComponents : `dict`, optional
81 `dict` mapping name of a derived component to another `StorageClass`.
82 parameters : `~collections.abc.Sequence` or `~collections.abc.Set`
83 Parameters understood by this `StorageClass` that can control
84 reading of data from datastores.
85 delegate : `str`, optional
86 Fully qualified name of class supporting assembly and disassembly
87 of a `pytype` instance.
88 converters : `dict` [`str`, `str`], optional
89 Mapping of python type to function that can be called to convert
90 that python type to the valid type of this storage class.
91 """
93 _cls_name: str = "BaseStorageClass"
94 _cls_components: dict[str, StorageClass] | None = None
95 _cls_derivedComponents: dict[str, StorageClass] | None = None
96 _cls_parameters: Set[str] | Sequence[str] | None = None
97 _cls_delegate: str | None = None
98 _cls_pytype: type | str | None = None
99 _cls_converters: dict[str, str] | None = None
100 defaultDelegate: type = StorageClassDelegate
101 defaultDelegateName: str = get_full_type_name(defaultDelegate)
103 def __init__(
104 self,
105 name: str | None = None,
106 pytype: type | str | None = None,
107 components: dict[str, StorageClass] | None = None,
108 derivedComponents: dict[str, StorageClass] | None = None,
109 parameters: Sequence[str] | Set[str] | None = None,
110 delegate: str | None = None,
111 converters: dict[str, str] | None = None,
112 ):
113 if name is None:
114 name = self._cls_name
115 if pytype is None: 115 ↛ 117line 115 didn't jump to line 117, because the condition on line 115 was never false
116 pytype = self._cls_pytype
117 if components is None: 117 ↛ 119line 117 didn't jump to line 119, because the condition on line 117 was never false
118 components = self._cls_components
119 if derivedComponents is None: 119 ↛ 121line 119 didn't jump to line 121, because the condition on line 119 was never false
120 derivedComponents = self._cls_derivedComponents
121 if parameters is None: 121 ↛ 123line 121 didn't jump to line 123, because the condition on line 121 was never false
122 parameters = self._cls_parameters
123 if delegate is None: 123 ↛ 127line 123 didn't jump to line 127, because the condition on line 123 was never false
124 delegate = self._cls_delegate
126 # Merge converters with class defaults.
127 self._converters = {}
128 if self._cls_converters is not None:
129 self._converters.update(self._cls_converters)
130 if converters: 130 ↛ 131line 130 didn't jump to line 131, because the condition on line 130 was never true
131 self._converters.update(converters)
133 # Version of converters where the python types have been
134 # Do not try to import anything until needed.
135 self._converters_by_type: dict[type, Callable[[Any], Any]] | None = None
137 self.name = name
139 if pytype is None:
140 pytype = object
142 self._pytype: type | None
143 if not isinstance(pytype, str):
144 # Already have a type so store it and get the name
145 self._pytypeName = get_full_type_name(pytype)
146 self._pytype = pytype
147 else:
148 # Store the type name and defer loading of type
149 self._pytypeName = pytype
150 self._pytype = None
152 if components is not None:
153 if len(components) == 1: 153 ↛ 154line 153 didn't jump to line 154, because the condition on line 153 was never true
154 raise ValueError(
155 f"Composite storage class {name} is not allowed to have"
156 f" only one component '{next(iter(components))}'."
157 " Did you mean it to be a derived component?"
158 )
159 self._components = components
160 else:
161 self._components = {}
162 self._derivedComponents = derivedComponents if derivedComponents is not None else {}
163 self._parameters = frozenset(parameters) if parameters is not None else frozenset()
164 # if the delegate is not None also set it and clear the default
165 # delegate
166 self._delegate: type | None
167 self._delegateClassName: str | None
168 if delegate is not None:
169 self._delegateClassName = delegate
170 self._delegate = None
171 elif components is not None: 171 ↛ 174line 171 didn't jump to line 174, because the condition on line 171 was never true
172 # We set a default delegate for composites so that a class is
173 # guaranteed to support something if it is a composite.
174 log.debug("Setting default delegate for %s", self.name)
175 self._delegate = self.defaultDelegate
176 self._delegateClassName = self.defaultDelegateName
177 else:
178 self._delegate = None
179 self._delegateClassName = None
181 @property
182 def components(self) -> Mapping[str, StorageClass]:
183 """Return the components associated with this `StorageClass`."""
184 return self._components
186 @property
187 def derivedComponents(self) -> Mapping[str, StorageClass]:
188 """Return derived components associated with `StorageClass`."""
189 return self._derivedComponents
191 @property
192 def converters(self) -> Mapping[str, str]:
193 """Return the type converters supported by this `StorageClass`."""
194 return self._converters
196 def _get_converters_by_type(self) -> Mapping[type, Callable[[Any], Any]]:
197 """Return the type converters as python types."""
198 if self._converters_by_type is None:
199 self._converters_by_type = {}
201 # Loop over list because the dict can be edited in loop.
202 for candidate_type_str, converter_str in list(self.converters.items()):
203 if hasattr(builtins, candidate_type_str):
204 candidate_type = getattr(builtins, candidate_type_str)
205 else:
206 try:
207 candidate_type = doImportType(candidate_type_str)
208 except ImportError as e:
209 log.warning(
210 "Unable to import type %s associated with storage class %s (%s)",
211 candidate_type_str,
212 self.name,
213 e,
214 )
215 del self._converters[candidate_type_str]
216 continue
218 try:
219 converter = doImportType(converter_str)
220 except ImportError as e:
221 log.warning(
222 "Unable to import conversion function %s associated with storage class %s "
223 "required to convert type %s (%s)",
224 converter_str,
225 self.name,
226 candidate_type_str,
227 e,
228 )
229 del self._converters[candidate_type_str]
230 continue
231 if not callable(converter):
232 # doImportType is annotated to return a Type but in actual
233 # fact it can return Any except ModuleType because package
234 # variables can be accessed. This make mypy believe it
235 # is impossible for the return value to not be a callable
236 # so we must ignore the warning.
237 log.warning( # type: ignore
238 "Conversion function %s associated with storage class "
239 "%s to convert type %s is not a callable.",
240 converter_str,
241 self.name,
242 candidate_type_str,
243 )
244 del self._converters[candidate_type_str]
245 continue
246 self._converters_by_type[candidate_type] = converter
247 return self._converters_by_type
249 @property
250 def parameters(self) -> set[str]:
251 """Return `set` of names of supported parameters."""
252 return set(self._parameters)
254 @property
255 def pytype(self) -> type:
256 """Return Python type associated with this `StorageClass`."""
257 if self._pytype is not None:
258 return self._pytype
260 if hasattr(builtins, self._pytypeName):
261 pytype = getattr(builtins, self._pytypeName)
262 else:
263 pytype = doImportType(self._pytypeName)
264 self._pytype = pytype
265 return self._pytype
267 @property
268 def delegateClass(self) -> type | None:
269 """Class to use to delegate type-specific actions."""
270 if self._delegate is not None:
271 return self._delegate
272 if self._delegateClassName is None:
273 return None
274 delegate_class = doImportType(self._delegateClassName)
275 self._delegate = delegate_class
276 return self._delegate
278 def allComponents(self) -> Mapping[str, StorageClass]:
279 """Return all defined components.
281 This mapping includes all the derived and read/write components
282 for the corresponding storage class.
284 Returns
285 -------
286 comp : `dict` of [`str`, `StorageClass`]
287 The component name to storage class mapping.
288 """
289 return ChainMap(self._components, self._derivedComponents)
291 def delegate(self) -> StorageClassDelegate:
292 """Return an instance of a storage class delegate.
294 Returns
295 -------
296 delegate : `StorageClassDelegate`
297 Instance of the delegate associated with this `StorageClass`.
298 The delegate is constructed with this `StorageClass`.
300 Raises
301 ------
302 TypeError
303 This StorageClass has no associated delegate.
304 """
305 cls = self.delegateClass
306 if cls is None:
307 raise TypeError(f"No delegate class is associated with StorageClass {self.name}")
308 return cls(storageClass=self)
310 def isComposite(self) -> bool:
311 """Return Boolean indicating whether this is a composite or not.
313 Returns
314 -------
315 isComposite : `bool`
316 `True` if this `StorageClass` is a composite, `False`
317 otherwise.
318 """
319 if self.components:
320 return True
321 return False
323 def _lookupNames(self) -> tuple[LookupKey, ...]:
324 """Keys to use when looking up this DatasetRef in a configuration.
326 The names are returned in order of priority.
328 Returns
329 -------
330 names : `tuple` of `LookupKey`
331 Tuple of a `LookupKey` using the `StorageClass` name.
332 """
333 return (LookupKey(name=self.name),)
335 def knownParameters(self) -> set[str]:
336 """Return set of all parameters known to this `StorageClass`.
338 The set includes parameters understood by components of a composite.
340 Returns
341 -------
342 known : `set`
343 All parameter keys of this `StorageClass` and the component
344 storage classes.
345 """
346 known = set(self._parameters)
347 for sc in self.components.values():
348 known.update(sc.knownParameters())
349 return known
351 def validateParameters(self, parameters: Collection | None = None) -> None:
352 """Check that the parameters are known to this `StorageClass`.
354 Does not check the values.
356 Parameters
357 ----------
358 parameters : `~collections.abc.Collection`, optional
359 Collection containing the parameters. Can be `dict`-like or
360 `set`-like. The parameter values are not checked.
361 If no parameters are supplied, always returns without error.
363 Raises
364 ------
365 KeyError
366 Some parameters are not understood by this `StorageClass`.
367 """
368 # No parameters is always okay
369 if not parameters:
370 return
372 # Extract the important information into a set. Works for dict and
373 # list.
374 external = set(parameters)
376 diff = external - self.knownParameters()
377 if diff:
378 s = "s" if len(diff) > 1 else ""
379 unknown = "', '".join(diff)
380 raise KeyError(f"Parameter{s} '{unknown}' not understood by StorageClass {self.name}")
382 def filterParameters(
383 self, parameters: Mapping[str, Any] | None, subset: Collection | None = None
384 ) -> Mapping[str, Any]:
385 """Filter out parameters that are not known to this `StorageClass`.
387 Parameters
388 ----------
389 parameters : `~collections.abc.Mapping`, optional
390 Candidate parameters. Can be `None` if no parameters have
391 been provided.
392 subset : `~collections.abc.Collection`, optional
393 Subset of supported parameters that the caller is interested
394 in using. The subset must be known to the `StorageClass`
395 if specified. If `None` the supplied parameters will all
396 be checked, else only the keys in this set will be checked.
398 Returns
399 -------
400 filtered : `~collections.abc.Mapping`
401 Valid parameters. Empty `dict` if none are suitable.
403 Raises
404 ------
405 ValueError
406 Raised if the provided subset is not a subset of the supported
407 parameters or if it is an empty set.
408 """
409 if not parameters:
410 return {}
412 known = self.knownParameters()
414 if subset is not None:
415 if not subset:
416 raise ValueError("Specified a parameter subset but it was empty")
417 subset = set(subset)
418 if not subset.issubset(known):
419 raise ValueError(f"Requested subset ({subset}) is not a subset of known parameters ({known})")
420 wanted = subset
421 else:
422 wanted = known
424 return {k: parameters[k] for k in wanted if k in parameters}
426 def validateInstance(self, instance: Any) -> bool:
427 """Check that the supplied Python object has the expected Python type.
429 Parameters
430 ----------
431 instance : `object`
432 Object to check.
434 Returns
435 -------
436 isOk : `bool`
437 True if the supplied instance object can be handled by this
438 `StorageClass`, False otherwise.
439 """
440 return isinstance(instance, self.pytype)
442 def is_type(self, other: type, compare_types: bool = False) -> bool:
443 """Return Boolean indicating whether the supplied type matches
444 the type in this `StorageClass`.
446 Parameters
447 ----------
448 other : `type`
449 The type to be checked.
450 compare_types : `bool`, optional
451 If `True` the python type will be used in the comparison
452 if the type names do not match. This may trigger an import
453 of code and so can be slower.
455 Returns
456 -------
457 match : `bool`
458 `True` if the types are equal.
460 Notes
461 -----
462 If this `StorageClass` has not yet imported the Python type the
463 check is done against the full type name, this prevents an attempt
464 to import the type when it will likely not match.
465 """
466 if self._pytype:
467 return self._pytype is other
469 other_name = get_full_type_name(other)
470 if self._pytypeName == other_name:
471 return True
473 if compare_types:
474 # Must protect against the import failing.
475 try:
476 return self.pytype is other
477 except Exception:
478 pass
480 return False
482 def can_convert(self, other: StorageClass) -> bool:
483 """Return `True` if this storage class can convert python types
484 in the other storage class.
486 Parameters
487 ----------
488 other : `StorageClass`
489 The storage class to check.
491 Returns
492 -------
493 can : `bool`
494 `True` if this storage class has a registered converter for
495 the python type associated with the other storage class. That
496 converter will convert the other python type to the one associated
497 with this storage class.
498 """
499 if other.name == self.name:
500 # Identical storage classes are compatible.
501 return True
503 # It may be that the storage class being compared is not
504 # available because the python type can't be imported. In that
505 # case conversion must be impossible.
506 try:
507 other_pytype = other.pytype
508 except Exception:
509 return False
511 # Or even this storage class itself can not have the type imported.
512 try:
513 self_pytype = self.pytype
514 except Exception:
515 return False
517 if issubclass(other_pytype, self_pytype):
518 # Storage classes have different names but the same python type.
519 return True
521 for candidate_type in self._get_converters_by_type():
522 if issubclass(other_pytype, candidate_type):
523 return True
524 return False
526 def coerce_type(self, incorrect: Any) -> Any:
527 """Coerce the supplied incorrect instance to the python type
528 associated with this `StorageClass`.
530 Parameters
531 ----------
532 incorrect : `object`
533 An object that might be the incorrect type.
535 Returns
536 -------
537 correct : `object`
538 An object that matches the python type of this `StorageClass`.
539 Can be the same object as given. If `None`, `None` will be
540 returned.
542 Raises
543 ------
544 TypeError
545 Raised if no conversion can be found.
546 """
547 if incorrect is None:
548 return None
550 # Possible this is the correct type already.
551 if self.validateInstance(incorrect):
552 return incorrect
554 # Check each registered converter.
555 for candidate_type, converter in self._get_converters_by_type().items():
556 if isinstance(incorrect, candidate_type):
557 try:
558 return converter(incorrect)
559 except Exception:
560 log.error(
561 "Converter %s failed to convert type %s",
562 get_full_type_name(converter),
563 get_full_type_name(incorrect),
564 )
565 raise
566 raise TypeError(
567 "Type does not match and no valid converter found to convert"
568 f" '{get_full_type_name(incorrect)}' to '{get_full_type_name(self.pytype)}'"
569 )
571 def __eq__(self, other: Any) -> bool:
572 """Equality checks name, pytype name, delegate name, and components."""
573 if not isinstance(other, StorageClass):
574 return NotImplemented
576 if self.name != other.name:
577 return False
579 # We must compare pytype and delegate by name since we do not want
580 # to trigger an import of external module code here
581 if self._delegateClassName != other._delegateClassName:
582 return False
583 if self._pytypeName != other._pytypeName:
584 return False
586 # Ensure we have the same component keys in each
587 if set(self.components.keys()) != set(other.components.keys()):
588 return False
590 # Same parameters
591 if self.parameters != other.parameters:
592 return False
594 # Ensure that all the components have the same type
595 return all(self.components[k] == other.components[k] for k in self.components)
597 def __hash__(self) -> int:
598 return hash(self.name)
600 def __repr__(self) -> str:
601 optionals: dict[str, Any] = {}
602 if self._pytypeName != "object":
603 optionals["pytype"] = self._pytypeName
604 if self._delegateClassName is not None:
605 optionals["delegate"] = self._delegateClassName
606 if self._parameters:
607 optionals["parameters"] = self._parameters
608 if self.components:
609 optionals["components"] = self.components
610 if self.converters:
611 optionals["converters"] = self.converters
613 # order is preserved in the dict
614 options = ", ".join(f"{k}={v!r}" for k, v in optionals.items())
616 # Start with mandatory fields
617 r = f"{self.__class__.__name__}({self.name!r}"
618 if options:
619 r = r + ", " + options
620 r = r + ")"
621 return r
623 def __str__(self) -> str:
624 return self.name
627class StorageClassFactory(metaclass=Singleton):
628 """Factory for `StorageClass` instances.
630 This class is a singleton, with each instance sharing the pool of
631 StorageClasses. Since code can not know whether it is the first
632 time the instance has been created, the constructor takes no arguments.
633 To populate the factory with storage classes, a call to
634 `~StorageClassFactory.addFromConfig()` should be made.
636 Parameters
637 ----------
638 config : `StorageClassConfig` or `str`, optional
639 Load configuration. In a ButlerConfig` the relevant configuration
640 is located in the ``storageClasses`` section.
641 """
643 def __init__(self, config: StorageClassConfig | str | None = None):
644 self._storageClasses: dict[str, StorageClass] = {}
645 self._configs: list[StorageClassConfig] = []
647 # Always seed with the default config
648 self.addFromConfig(StorageClassConfig())
650 if config is not None: 650 ↛ 651line 650 didn't jump to line 651, because the condition on line 650 was never true
651 self.addFromConfig(config)
653 def __str__(self) -> str:
654 """Return summary of factory.
656 Returns
657 -------
658 summary : `str`
659 Summary of the factory status.
660 """
661 sep = "\n"
662 return f"""Number of registered StorageClasses: {len(self._storageClasses)}
664StorageClasses
665--------------
666{sep.join(f"{s}: {self._storageClasses[s]}" for s in self._storageClasses)}
667"""
669 def __contains__(self, storageClassOrName: StorageClass | str) -> bool:
670 """Indicate whether the storage class exists in the factory.
672 Parameters
673 ----------
674 storageClassOrName : `str` or `StorageClass`
675 If `str` is given existence of the named StorageClass
676 in the factory is checked. If `StorageClass` is given
677 existence and equality are checked.
679 Returns
680 -------
681 in : `bool`
682 True if the supplied string is present, or if the supplied
683 `StorageClass` is present and identical.
685 Notes
686 -----
687 The two different checks (one for "key" and one for "value") based on
688 the type of the given argument mean that it is possible for
689 StorageClass.name to be in the factory but StorageClass to not be
690 in the factory.
691 """
692 if isinstance(storageClassOrName, str): 692 ↛ 694line 692 didn't jump to line 694, because the condition on line 692 was never false
693 return storageClassOrName in self._storageClasses
694 elif isinstance(storageClassOrName, StorageClass) and storageClassOrName.name in self._storageClasses:
695 return storageClassOrName == self._storageClasses[storageClassOrName.name]
696 return False
698 def __len__(self) -> int:
699 return len(self._storageClasses)
701 def __iter__(self) -> Iterator[str]:
702 return iter(self._storageClasses)
704 def values(self) -> ValuesView[StorageClass]:
705 return self._storageClasses.values()
707 def keys(self) -> KeysView[str]:
708 return self._storageClasses.keys()
710 def items(self) -> ItemsView[str, StorageClass]:
711 return self._storageClasses.items()
713 def addFromConfig(self, config: StorageClassConfig | Config | str) -> None:
714 """Add more `StorageClass` definitions from a config file.
716 Parameters
717 ----------
718 config : `StorageClassConfig`, `Config` or `str`
719 Storage class configuration. Can contain a ``storageClasses``
720 key if part of a global configuration.
721 """
722 sconfig = StorageClassConfig(config)
723 self._configs.append(sconfig)
725 # Since we can not assume that we will get definitions of
726 # components or parents before their classes are defined
727 # we have a helper function that we can call recursively
728 # to extract definitions from the configuration.
729 def processStorageClass(name: str, sconfig: StorageClassConfig, msg: str = "") -> None:
730 # Maybe we've already processed this through recursion
731 if name not in sconfig:
732 return
733 info = sconfig.pop(name)
735 # Always create the storage class so we can ensure that
736 # we are not trying to overwrite with a different definition
737 components = None
739 # Extract scalar items from dict that are needed for
740 # StorageClass Constructor
741 storageClassKwargs = {k: info[k] for k in ("pytype", "delegate", "parameters") if k in info}
743 if "converters" in info:
744 storageClassKwargs["converters"] = info["converters"].toDict()
746 for compName in ("components", "derivedComponents"):
747 if compName not in info:
748 continue
749 components = {}
750 for cname, ctype in info[compName].items():
751 if ctype not in self:
752 processStorageClass(ctype, sconfig, msg)
753 components[cname] = self.getStorageClass(ctype)
755 # Fill in other items
756 storageClassKwargs[compName] = components
758 # Create the new storage class and register it
759 baseClass = None
760 if "inheritsFrom" in info:
761 baseName = info["inheritsFrom"]
762 if baseName not in self: 762 ↛ 763line 762 didn't jump to line 763, because the condition on line 762 was never true
763 processStorageClass(baseName, sconfig, msg)
764 baseClass = type(self.getStorageClass(baseName))
766 newStorageClassType = self.makeNewStorageClass(name, baseClass, **storageClassKwargs)
767 newStorageClass = newStorageClassType()
768 self.registerStorageClass(newStorageClass, msg=msg)
770 # In case there is a problem, construct a context message for any
771 # error reporting.
772 files = [str(f) for f in itertools.chain([sconfig.configFile], sconfig.filesRead) if f]
773 context = f"when adding definitions from {', '.join(files)}" if files else ""
774 log.debug("Adding definitions from config %s", ", ".join(files))
776 for name in list(sconfig.keys()):
777 processStorageClass(name, sconfig, context)
779 @staticmethod
780 def makeNewStorageClass(
781 name: str, baseClass: type[StorageClass] | None = StorageClass, **kwargs: Any
782 ) -> type[StorageClass]:
783 """Create a new Python class as a subclass of `StorageClass`.
785 Parameters
786 ----------
787 name : `str`
788 Name to use for this class.
789 baseClass : `type`, optional
790 Base class for this `StorageClass`. Must be either `StorageClass`
791 or a subclass of `StorageClass`. If `None`, `StorageClass` will
792 be used.
794 Returns
795 -------
796 newtype : `type` subclass of `StorageClass`
797 Newly created Python type.
798 """
799 if baseClass is None:
800 baseClass = StorageClass
801 if not issubclass(baseClass, StorageClass): 801 ↛ 802line 801 didn't jump to line 802, because the condition on line 801 was never true
802 raise ValueError(f"Base class must be a StorageClass not {baseClass}")
804 # convert the arguments to use different internal names
805 clsargs = {f"_cls_{k}": v for k, v in kwargs.items() if v is not None}
806 clsargs["_cls_name"] = name
808 # Some container items need to merge with the base class values
809 # so that a child can inherit but override one bit.
810 # lists (which you get from configs) are treated as sets for this to
811 # work consistently.
812 for k in ("components", "parameters", "derivedComponents", "converters"):
813 classKey = f"_cls_{k}"
814 if classKey in clsargs:
815 baseValue = getattr(baseClass, classKey, None)
816 if baseValue is not None:
817 currentValue = clsargs[classKey]
818 if isinstance(currentValue, dict): 818 ↛ 821line 818 didn't jump to line 821, because the condition on line 818 was never false
819 newValue = baseValue.copy()
820 else:
821 newValue = set(baseValue)
822 newValue.update(currentValue)
823 clsargs[classKey] = newValue
825 # If we have parameters they should be a frozen set so that the
826 # parameters in the class can not be modified.
827 pk = "_cls_parameters"
828 if pk in clsargs:
829 clsargs[pk] = frozenset(clsargs[pk])
831 return type(f"StorageClass{name}", (baseClass,), clsargs)
833 def getStorageClass(self, storageClassName: str) -> StorageClass:
834 """Get a StorageClass instance associated with the supplied name.
836 Parameters
837 ----------
838 storageClassName : `str`
839 Name of the storage class to retrieve.
841 Returns
842 -------
843 instance : `StorageClass`
844 Instance of the correct `StorageClass`.
846 Raises
847 ------
848 KeyError
849 The requested storage class name is not registered.
850 """
851 return self._storageClasses[storageClassName]
853 def findStorageClass(self, pytype: type, compare_types: bool = False) -> StorageClass:
854 """Find the storage class associated with this python type.
856 Parameters
857 ----------
858 pytype : `type`
859 The Python type to be matched.
860 compare_types : `bool`, optional
861 If `False`, the type will be checked against name of the python
862 type. This comparison is always done first. If `True` and the
863 string comparison failed, each candidate storage class will be
864 forced to have its type imported. This can be significantly slower.
866 Returns
867 -------
868 storageClass : `StorageClass`
869 The matching storage class.
871 Raises
872 ------
873 KeyError
874 Raised if no match could be found.
876 Notes
877 -----
878 It is possible for a python type to be associated with multiple
879 storage classes. This method will currently return the first that
880 matches.
881 """
882 result = self._find_storage_class(pytype, False)
883 if result:
884 return result
886 if compare_types:
887 # The fast comparison failed and we were asked to try the
888 # variant that might involve code imports.
889 result = self._find_storage_class(pytype, True)
890 if result:
891 return result
893 raise KeyError(f"Unable to find a StorageClass associated with type {get_full_type_name(pytype)!r}")
895 def _find_storage_class(self, pytype: type, compare_types: bool) -> StorageClass | None:
896 """Iterate through all storage classes to find a match.
898 Parameters
899 ----------
900 pytype : `type`
901 The Python type to be matched.
902 compare_types : `bool`, optional
903 Whether to use type name matching or explicit type matching.
904 The latter can be slower.
906 Returns
907 -------
908 storageClass : `StorageClass` or `None`
909 The matching storage class, or `None` if no match was found.
911 Notes
912 -----
913 Helper method for ``findStorageClass``.
914 """
915 for storageClass in self.values():
916 if storageClass.is_type(pytype, compare_types=compare_types):
917 return storageClass
918 return None
920 def registerStorageClass(self, storageClass: StorageClass, msg: str | None = None) -> None:
921 """Store the `StorageClass` in the factory.
923 Will be indexed by `StorageClass.name` and will return instances
924 of the supplied `StorageClass`.
926 Parameters
927 ----------
928 storageClass : `StorageClass`
929 Type of the Python `StorageClass` to register.
930 msg : `str`, optional
931 Additional message string to be included in any error message.
933 Raises
934 ------
935 ValueError
936 If a storage class has already been registered with
937 that storage class name and the previous definition differs.
938 """
939 if storageClass.name in self._storageClasses: 939 ↛ 940line 939 didn't jump to line 940, because the condition on line 939 was never true
940 existing = self.getStorageClass(storageClass.name)
941 if existing != storageClass:
942 errmsg = f" {msg}" if msg else ""
943 raise ValueError(
944 f"New definition for StorageClass {storageClass.name} ({storageClass!r}) "
945 f"differs from current definition ({existing!r}){errmsg}"
946 )
947 else:
948 self._storageClasses[storageClass.name] = storageClass
950 def _unregisterStorageClass(self, storageClassName: str) -> None:
951 """Remove the named StorageClass from the factory.
953 Parameters
954 ----------
955 storageClassName : `str`
956 Name of storage class to remove.
958 Raises
959 ------
960 KeyError
961 The named storage class is not registered.
963 Notes
964 -----
965 This method is intended to simplify testing of StorageClassFactory
966 functionality and it is not expected to be required for normal usage.
967 """
968 del self._storageClasses[storageClassName]