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"""Functions to interact with mapped classes and instances.""" |
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import inspect |
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import logging |
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import warnings |
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from . import common, exceptions |
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log = logging.getLogger(__name__) |
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def create(class_or_instance, *args, overwrite=False): |
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"""Create a new mapped object.""" |
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instance = _instantiate(class_or_instance, *args) |
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mapper = common.get_mapper(instance, expected=True) |
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if mapper.auto_create: |
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msg = "'create' is called automatically with 'auto_create' enabled" |
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warnings.warn(msg) |
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if mapper.exists and not overwrite: |
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msg = "{!r} already exists".format(mapper.path) |
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raise exceptions.DuplicateMappingError(msg) |
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return save(instance) |
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def find(class_or_instance, *args, create=False): # pylint: disable=redefined-outer-name |
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"""Find a matching mapped object or return None.""" |
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instance = _instantiate(class_or_instance, *args) |
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mapper = common.get_mapper(instance, expected=True) |
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if mapper.exists: |
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return instance |
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elif create: |
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return save(instance) |
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else: |
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return None |
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def find_all(cls, **kwargs): |
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"""Return a list of all matching mapped objects.""" |
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log.debug((cls, kwargs)) |
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raise NotImplementedError |
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def load(instance): |
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"""Force the loading of a mapped object's file.""" |
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mapper = common.get_mapper(instance, expected=True) |
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warnings.warn("'load' is called automatically") |
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mapper.load() |
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return instance |
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def save(instance): |
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"""Save a mapped object to file.""" |
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mapper = common.get_mapper(instance, expected=True) |
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if mapper.auto_save: |
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msg = "'save' is called automatically with 'auto_save' enabled" |
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warnings.warn(msg) |
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if mapper.deleted: |
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msg = "{!r} was deleted".format(mapper.path) |
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raise exceptions.DeletedFileError(msg) |
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if not mapper.exists: |
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mapper.create() |
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mapper.save() |
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return instance |
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def delete(instance): |
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"""Delete a mapped object's file.""" |
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mapper = common.get_mapper(instance, expected=True) |
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mapper.delete() |
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return None |
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def _instantiate(class_or_instance, *args): |
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if inspect.isclass(class_or_instance): |
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instance = class_or_instance(*args) |
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else: |
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assert not args |
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instance = class_or_instance |
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return instance |
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