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c89b18aa95
Differentiating between when the generated file content is required and when the generated file is just required to exist gives us more flexibility with strategies.
59 lines
1.4 KiB
Python
59 lines
1.4 KiB
Python
from django.utils.functional import LazyObject
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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_created(self, file):
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file.generate()
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def on_source_changed(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, basestring):
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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 unicode(self._wrapped)
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def __str__(self):
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return str(self._wrapped)
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