113 lines
3.4 KiB
Python
113 lines
3.4 KiB
Python
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"""Extensible memoizing collections and decorators."""
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from __future__ import absolute_import
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import functools
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from . import keys
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from .cache import Cache
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from .lfu import LFUCache
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from .lru import LRUCache
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from .rr import RRCache
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from .ttl import TTLCache
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__all__ = (
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'Cache', 'LFUCache', 'LRUCache', 'RRCache', 'TTLCache',
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'cached', 'cachedmethod'
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)
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__version__ = '3.0.0'
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if hasattr(functools.update_wrapper(lambda f: f(), lambda: 42), '__wrapped__'):
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_update_wrapper = functools.update_wrapper
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else:
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def _update_wrapper(wrapper, wrapped):
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functools.update_wrapper(wrapper, wrapped)
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wrapper.__wrapped__ = wrapped
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return wrapper
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def cached(cache, key=keys.hashkey, lock=None):
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"""Decorator to wrap a function with a memoizing callable that saves
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results in a cache.
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"""
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def decorator(func):
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if cache is None:
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def wrapper(*args, **kwargs):
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return func(*args, **kwargs)
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elif lock is None:
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def wrapper(*args, **kwargs):
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k = key(*args, **kwargs)
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try:
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return cache[k]
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except KeyError:
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pass # key not found
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v = func(*args, **kwargs)
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try:
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cache[k] = v
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except ValueError:
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pass # value too large
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return v
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else:
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def wrapper(*args, **kwargs):
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k = key(*args, **kwargs)
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try:
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with lock:
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return cache[k]
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except KeyError:
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pass # key not found
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v = func(*args, **kwargs)
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try:
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with lock:
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cache[k] = v
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except ValueError:
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pass # value too large
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return v
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return _update_wrapper(wrapper, func)
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return decorator
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def cachedmethod(cache, key=keys.hashkey, lock=None):
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"""Decorator to wrap a class or instance method with a memoizing
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callable that saves results in a cache.
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"""
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def decorator(method):
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if lock is None:
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def wrapper(self, *args, **kwargs):
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c = cache(self)
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if c is None:
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return method(self, *args, **kwargs)
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k = key(*args, **kwargs)
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try:
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return c[k]
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except KeyError:
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pass # key not found
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v = method(self, *args, **kwargs)
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try:
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c[k] = v
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except ValueError:
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pass # value too large
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return v
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else:
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def wrapper(self, *args, **kwargs):
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c = cache(self)
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if c is None:
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return method(self, *args, **kwargs)
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k = key(*args, **kwargs)
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try:
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with lock(self):
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return c[k]
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except KeyError:
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pass # key not found
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v = method(self, *args, **kwargs)
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try:
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with lock(self):
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c[k] = v
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except ValueError:
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pass # value too large
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return v
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return _update_wrapper(wrapper, method)
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return decorator
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