Added delete option to database storage.

venv/Lib/site-packages/cachetools/func.py

@@ -0,0 +1,147 @@
+"""`functools.lru_cache` compatible memoizing function decorators."""
+
+import collections
+import functools
+import math
+import random
+import time
+
+try:
+    from threading import RLock
+except ImportError:  # pragma: no cover
+    from dummy_threading import RLock
+
+from . import keys
+from .lfu import LFUCache
+from .lru import LRUCache
+from .rr import RRCache
+from .ttl import TTLCache
+
+__all__ = ('lfu_cache', 'lru_cache', 'rr_cache', 'ttl_cache')
+
+
+_CacheInfo = collections.namedtuple('CacheInfo', [
+    'hits', 'misses', 'maxsize', 'currsize'
+])
+
+
+class _UnboundCache(dict):
+
+    @property
+    def maxsize(self):
+        return None
+
+    @property
+    def currsize(self):
+        return len(self)
+
+
+class _UnboundTTLCache(TTLCache):
+    def __init__(self, ttl, timer):
+        TTLCache.__init__(self, math.inf, ttl, timer)
+
+    @property
+    def maxsize(self):
+        return None
+
+
+def _cache(cache, typed):
+    maxsize = cache.maxsize
+
+    def decorator(func):
+        key = keys.typedkey if typed else keys.hashkey
+        lock = RLock()
+        stats = [0, 0]
+
+        def wrapper(*args, **kwargs):
+            k = key(*args, **kwargs)
+            with lock:
+                try:
+                    v = cache[k]
+                    stats[0] += 1
+                    return v
+                except KeyError:
+                    stats[1] += 1
+            v = func(*args, **kwargs)
+            try:
+                with lock:
+                    cache[k] = v
+            except ValueError:
+                pass  # value too large
+            return v
+
+        def cache_info():
+            with lock:
+                hits, misses = stats
+                maxsize = cache.maxsize
+                currsize = cache.currsize
+            return _CacheInfo(hits, misses, maxsize, currsize)
+
+        def cache_clear():
+            with lock:
+                try:
+                    cache.clear()
+                finally:
+                    stats[:] = [0, 0]
+
+        wrapper.cache_info = cache_info
+        wrapper.cache_clear = cache_clear
+        wrapper.cache_parameters = lambda: {'maxsize': maxsize, 'typed': typed}
+        functools.update_wrapper(wrapper, func)
+        return wrapper
+    return decorator
+
+
+def lfu_cache(maxsize=128, typed=False):
+    """Decorator to wrap a function with a memoizing callable that saves
+    up to `maxsize` results based on a Least Frequently Used (LFU)
+    algorithm.
+
+    """
+    if maxsize is None:
+        return _cache(_UnboundCache(), typed)
+    elif callable(maxsize):
+        return _cache(LFUCache(128), typed)(maxsize)
+    else:
+        return _cache(LFUCache(maxsize), typed)
+
+
+def lru_cache(maxsize=128, typed=False):
+    """Decorator to wrap a function with a memoizing callable that saves
+    up to `maxsize` results based on a Least Recently Used (LRU)
+    algorithm.
+
+    """
+    if maxsize is None:
+        return _cache(_UnboundCache(), typed)
+    elif callable(maxsize):
+        return _cache(LRUCache(128), typed)(maxsize)
+    else:
+        return _cache(LRUCache(maxsize), typed)
+
+
+def rr_cache(maxsize=128, choice=random.choice, typed=False):
+    """Decorator to wrap a function with a memoizing callable that saves
+    up to `maxsize` results based on a Random Replacement (RR)
+    algorithm.
+
+    """
+    if maxsize is None:
+        return _cache(_UnboundCache(), typed)
+    elif callable(maxsize):
+        return _cache(RRCache(128, choice), typed)(maxsize)
+    else:
+        return _cache(RRCache(maxsize, choice), typed)
+
+
+def ttl_cache(maxsize=128, ttl=600, timer=time.monotonic, typed=False):
+    """Decorator to wrap a function with a memoizing callable that saves
+    up to `maxsize` results based on a Least Recently Used (LRU)
+    algorithm with a per-item time-to-live (TTL) value.
+    """
+    if maxsize is None:
+        return _cache(_UnboundTTLCache(ttl, timer), typed)
+    elif callable(maxsize):
+        return _cache(TTLCache(128, ttl, timer), typed)(maxsize)
+    else:
+        return _cache(TTLCache(maxsize, ttl, timer), typed)