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59 lines
1.4 KiB
Python
59 lines
1.4 KiB
Python
import six
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from django.utils.functional import LazyObject
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from ..lib import force_text
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from ..utils import get_singleton
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class JustInTime(object):
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"""
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A strategy that ensures the file exists right before it's needed.
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"""
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def on_existence_required(self, file):
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file.generate()
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def on_content_required(self, file):
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file.generate()
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class Optimistic(object):
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"""
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A strategy that acts immediately when the source file changes and assumes
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that the cache files will not be removed (i.e. it doesn't ensure the
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cache file exists when it's accessed).
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"""
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def on_source_saved(self, file):
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file.generate()
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class DictStrategy(object):
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def __init__(self, callbacks):
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for k, v in callbacks.items():
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setattr(self, k, v)
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class StrategyWrapper(LazyObject):
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def __init__(self, strategy):
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if isinstance(strategy, six.string_types):
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strategy = get_singleton(strategy, 'cache file strategy')
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elif isinstance(strategy, dict):
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strategy = DictStrategy(strategy)
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elif callable(strategy):
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strategy = strategy()
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self._wrapped = strategy
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def __getstate__(self):
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return {'_wrapped': self._wrapped}
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def __setstate__(self, state):
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self._wrapped = state['_wrapped']
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def __unicode__(self):
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return force_text(self._wrapped)
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def __str__(self):
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return str(self._wrapped)
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