Added delete option to database storage.

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

@@ -0,0 +1,20 @@
+"""Extensible memoizing collections and decorators."""
+
+from .cache import Cache
+from .decorators import cached, cachedmethod
+from .lfu import LFUCache
+from .lru import LRUCache
+from .rr import RRCache
+from .ttl import TTLCache
+
+__all__ = (
+    'Cache',
+    'LFUCache',
+    'LRUCache',
+    'RRCache',
+    'TTLCache',
+    'cached',
+    'cachedmethod'
+)
+
+__version__ = '4.1.1'

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

@@ -0,0 +1,46 @@
+from abc import abstractmethod
+from collections.abc import MutableMapping
+
+
+class DefaultMapping(MutableMapping):
+
+    __slots__ = ()
+
+    @abstractmethod
+    def __contains__(self, key):  # pragma: nocover
+        return False
+
+    @abstractmethod
+    def __getitem__(self, key):  # pragma: nocover
+        if hasattr(self.__class__, '__missing__'):
+            return self.__class__.__missing__(self, key)
+        else:
+            raise KeyError(key)
+
+    def get(self, key, default=None):
+        if key in self:
+            return self[key]
+        else:
+            return default
+
+    __marker = object()
+
+    def pop(self, key, default=__marker):
+        if key in self:
+            value = self[key]
+            del self[key]
+        elif default is self.__marker:
+            raise KeyError(key)
+        else:
+            value = default
+        return value
+
+    def setdefault(self, key, default=None):
+        if key in self:
+            value = self[key]
+        else:
+            self[key] = value = default
+        return value
+
+
+DefaultMapping.register(dict)

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

@@ -0,0 +1,89 @@
+from .abc import DefaultMapping
+
+
+class _DefaultSize(object):
+    def __getitem__(self, _):
+        return 1
+
+    def __setitem__(self, _, value):
+        assert value == 1
+
+    def pop(self, _):
+        return 1
+
+
+class Cache(DefaultMapping):
+    """Mutable mapping to serve as a simple cache or cache base class."""
+
+    __size = _DefaultSize()
+
+    def __init__(self, maxsize, getsizeof=None):
+        if getsizeof:
+            self.getsizeof = getsizeof
+        if self.getsizeof is not Cache.getsizeof:
+            self.__size = dict()
+        self.__data = dict()
+        self.__currsize = 0
+        self.__maxsize = maxsize
+
+    def __repr__(self):
+        return '%s(%r, maxsize=%r, currsize=%r)' % (
+            self.__class__.__name__,
+            list(self.__data.items()),
+            self.__maxsize,
+            self.__currsize,
+        )
+
+    def __getitem__(self, key):
+        try:
+            return self.__data[key]
+        except KeyError:
+            return self.__missing__(key)
+
+    def __setitem__(self, key, value):
+        maxsize = self.__maxsize
+        size = self.getsizeof(value)
+        if size > maxsize:
+            raise ValueError('value too large')
+        if key not in self.__data or self.__size[key] < size:
+            while self.__currsize + size > maxsize:
+                self.popitem()
+        if key in self.__data:
+            diffsize = size - self.__size[key]
+        else:
+            diffsize = size
+        self.__data[key] = value
+        self.__size[key] = size
+        self.__currsize += diffsize
+
+    def __delitem__(self, key):
+        size = self.__size.pop(key)
+        del self.__data[key]
+        self.__currsize -= size
+
+    def __contains__(self, key):
+        return key in self.__data
+
+    def __missing__(self, key):
+        raise KeyError(key)
+
+    def __iter__(self):
+        return iter(self.__data)
+
+    def __len__(self):
+        return len(self.__data)
+
+    @property
+    def maxsize(self):
+        """The maximum size of the cache."""
+        return self.__maxsize
+
+    @property
+    def currsize(self):
+        """The current size of the cache."""
+        return self.__currsize
+
+    @staticmethod
+    def getsizeof(value):
+        """Return the size of a cache element's value."""
+        return 1

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

@@ -0,0 +1,88 @@
+import functools
+
+from .keys import hashkey
+
+
+def cached(cache, key=hashkey, lock=None):
+    """Decorator to wrap a function with a memoizing callable that saves
+    results in a cache.
+
+    """
+    def decorator(func):
+        if cache is None:
+            def wrapper(*args, **kwargs):
+                return func(*args, **kwargs)
+        elif lock is None:
+            def wrapper(*args, **kwargs):
+                k = key(*args, **kwargs)
+                try:
+                    return cache[k]
+                except KeyError:
+                    pass  # key not found
+                v = func(*args, **kwargs)
+                try:
+                    cache[k] = v
+                except ValueError:
+                    pass  # value too large
+                return v
+        else:
+            def wrapper(*args, **kwargs):
+                k = key(*args, **kwargs)
+                try:
+                    with lock:
+                        return cache[k]
+                except KeyError:
+                    pass  # key not found
+                v = func(*args, **kwargs)
+                try:
+                    with lock:
+                        cache[k] = v
+                except ValueError:
+                    pass  # value too large
+                return v
+        return functools.update_wrapper(wrapper, func)
+    return decorator
+
+
+def cachedmethod(cache, key=hashkey, lock=None):
+    """Decorator to wrap a class or instance method with a memoizing
+    callable that saves results in a cache.
+
+    """
+    def decorator(method):
+        if lock is None:
+            def wrapper(self, *args, **kwargs):
+                c = cache(self)
+                if c is None:
+                    return method(self, *args, **kwargs)
+                k = key(*args, **kwargs)
+                try:
+                    return c[k]
+                except KeyError:
+                    pass  # key not found
+                v = method(self, *args, **kwargs)
+                try:
+                    c[k] = v
+                except ValueError:
+                    pass  # value too large
+                return v
+        else:
+            def wrapper(self, *args, **kwargs):
+                c = cache(self)
+                if c is None:
+                    return method(self, *args, **kwargs)
+                k = key(*args, **kwargs)
+                try:
+                    with lock(self):
+                        return c[k]
+                except KeyError:
+                    pass  # key not found
+                v = method(self, *args, **kwargs)
+                try:
+                    with lock(self):
+                        c[k] = v
+                except ValueError:
+                    pass  # value too large
+                return v
+        return functools.update_wrapper(wrapper, method)
+    return decorator

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)

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

@@ -0,0 +1,52 @@
+"""Key functions for memoizing decorators."""
+
+__all__ = ('hashkey', 'typedkey')
+
+
+class _HashedTuple(tuple):
+    """A tuple that ensures that hash() will be called no more than once
+    per element, since cache decorators will hash the key multiple
+    times on a cache miss.  See also _HashedSeq in the standard
+    library functools implementation.
+
+    """
+
+    __hashvalue = None
+
+    def __hash__(self, hash=tuple.__hash__):
+        hashvalue = self.__hashvalue
+        if hashvalue is None:
+            self.__hashvalue = hashvalue = hash(self)
+        return hashvalue
+
+    def __add__(self, other, add=tuple.__add__):
+        return _HashedTuple(add(self, other))
+
+    def __radd__(self, other, add=tuple.__add__):
+        return _HashedTuple(add(other, self))
+
+    def __getstate__(self):
+        return {}
+
+
+# used for separating keyword arguments; we do not use an object
+# instance here so identity is preserved when pickling/unpickling
+_kwmark = (_HashedTuple,)
+
+
+def hashkey(*args, **kwargs):
+    """Return a cache key for the specified hashable arguments."""
+
+    if kwargs:
+        return _HashedTuple(args + sum(sorted(kwargs.items()), _kwmark))
+    else:
+        return _HashedTuple(args)
+
+
+def typedkey(*args, **kwargs):
+    """Return a typed cache key for the specified hashable arguments."""
+
+    key = hashkey(*args, **kwargs)
+    key += tuple(type(v) for v in args)
+    key += tuple(type(v) for _, v in sorted(kwargs.items()))
+    return key

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

@@ -0,0 +1,34 @@
+import collections
+
+from .cache import Cache
+
+
+class LFUCache(Cache):
+    """Least Frequently Used (LFU) cache implementation."""
+
+    def __init__(self, maxsize, getsizeof=None):
+        Cache.__init__(self, maxsize, getsizeof)
+        self.__counter = collections.Counter()
+
+    def __getitem__(self, key, cache_getitem=Cache.__getitem__):
+        value = cache_getitem(self, key)
+        self.__counter[key] -= 1
+        return value
+
+    def __setitem__(self, key, value, cache_setitem=Cache.__setitem__):
+        cache_setitem(self, key, value)
+        self.__counter[key] -= 1
+
+    def __delitem__(self, key, cache_delitem=Cache.__delitem__):
+        cache_delitem(self, key)
+        del self.__counter[key]
+
+    def popitem(self):
+        """Remove and return the `(key, value)` pair least frequently used."""
+        try:
+            (key, _), = self.__counter.most_common(1)
+        except ValueError:
+            msg = '%s is empty' % self.__class__.__name__
+            raise KeyError(msg) from None
+        else:
+            return (key, self.pop(key))

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

@@ -0,0 +1,40 @@
+import collections
+
+from .cache import Cache
+
+
+class LRUCache(Cache):
+    """Least Recently Used (LRU) cache implementation."""
+
+    def __init__(self, maxsize, getsizeof=None):
+        Cache.__init__(self, maxsize, getsizeof)
+        self.__order = collections.OrderedDict()
+
+    def __getitem__(self, key, cache_getitem=Cache.__getitem__):
+        value = cache_getitem(self, key)
+        self.__update(key)
+        return value
+
+    def __setitem__(self, key, value, cache_setitem=Cache.__setitem__):
+        cache_setitem(self, key, value)
+        self.__update(key)
+
+    def __delitem__(self, key, cache_delitem=Cache.__delitem__):
+        cache_delitem(self, key)
+        del self.__order[key]
+
+    def popitem(self):
+        """Remove and return the `(key, value)` pair least recently used."""
+        try:
+            key = next(iter(self.__order))
+        except StopIteration:
+            msg = '%s is empty' % self.__class__.__name__
+            raise KeyError(msg) from None
+        else:
+            return (key, self.pop(key))
+
+    def __update(self, key):
+        try:
+            self.__order.move_to_end(key)
+        except KeyError:
+            self.__order[key] = None

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

@@ -0,0 +1,35 @@
+import random
+
+from .cache import Cache
+
+
+# random.choice cannot be pickled in Python 2.7
+def _choice(seq):
+    return random.choice(seq)
+
+
+class RRCache(Cache):
+    """Random Replacement (RR) cache implementation."""
+
+    def __init__(self, maxsize, choice=random.choice, getsizeof=None):
+        Cache.__init__(self, maxsize, getsizeof)
+        # TODO: use None as default, assing to self.choice directly?
+        if choice is random.choice:
+            self.__choice = _choice
+        else:
+            self.__choice = choice
+
+    @property
+    def choice(self):
+        """The `choice` function used by the cache."""
+        return self.__choice
+
+    def popitem(self):
+        """Remove and return a random `(key, value)` pair."""
+        try:
+            key = self.__choice(list(self))
+        except IndexError:
+            msg = '%s is empty' % self.__class__.__name__
+            raise KeyError(msg) from None
+        else:
+            return (key, self.pop(key))

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

@@ -0,0 +1,209 @@
+import collections
+import time
+
+from .cache import Cache
+
+
+class _Link(object):
+
+    __slots__ = ('key', 'expire', 'next', 'prev')
+
+    def __init__(self, key=None, expire=None):
+        self.key = key
+        self.expire = expire
+
+    def __reduce__(self):
+        return _Link, (self.key, self.expire)
+
+    def unlink(self):
+        next = self.next
+        prev = self.prev
+        prev.next = next
+        next.prev = prev
+
+
+class _Timer(object):
+
+    def __init__(self, timer):
+        self.__timer = timer
+        self.__nesting = 0
+
+    def __call__(self):
+        if self.__nesting == 0:
+            return self.__timer()
+        else:
+            return self.__time
+
+    def __enter__(self):
+        if self.__nesting == 0:
+            self.__time = time = self.__timer()
+        else:
+            time = self.__time
+        self.__nesting += 1
+        return time
+
+    def __exit__(self, *exc):
+        self.__nesting -= 1
+
+    def __reduce__(self):
+        return _Timer, (self.__timer,)
+
+    def __getattr__(self, name):
+        return getattr(self.__timer, name)
+
+
+class TTLCache(Cache):
+    """LRU Cache implementation with per-item time-to-live (TTL) value."""
+
+    def __init__(self, maxsize, ttl, timer=time.monotonic, getsizeof=None):
+        Cache.__init__(self, maxsize, getsizeof)
+        self.__root = root = _Link()
+        root.prev = root.next = root
+        self.__links = collections.OrderedDict()
+        self.__timer = _Timer(timer)
+        self.__ttl = ttl
+
+    def __contains__(self, key):
+        try:
+            link = self.__links[key]  # no reordering
+        except KeyError:
+            return False
+        else:
+            return not (link.expire < self.__timer())
+
+    def __getitem__(self, key, cache_getitem=Cache.__getitem__):
+        try:
+            link = self.__getlink(key)
+        except KeyError:
+            expired = False
+        else:
+            expired = link.expire < self.__timer()
+        if expired:
+            return self.__missing__(key)
+        else:
+            return cache_getitem(self, key)
+
+    def __setitem__(self, key, value, cache_setitem=Cache.__setitem__):
+        with self.__timer as time:
+            self.expire(time)
+            cache_setitem(self, key, value)
+        try:
+            link = self.__getlink(key)
+        except KeyError:
+            self.__links[key] = link = _Link(key)
+        else:
+            link.unlink()
+        link.expire = time + self.__ttl
+        link.next = root = self.__root
+        link.prev = prev = root.prev
+        prev.next = root.prev = link
+
+    def __delitem__(self, key, cache_delitem=Cache.__delitem__):
+        cache_delitem(self, key)
+        link = self.__links.pop(key)
+        link.unlink()
+        if link.expire < self.__timer():
+            raise KeyError(key)
+
+    def __iter__(self):
+        root = self.__root
+        curr = root.next
+        while curr is not root:
+            # "freeze" time for iterator access
+            with self.__timer as time:
+                if not (curr.expire < time):
+                    yield curr.key
+            curr = curr.next
+
+    def __len__(self):
+        root = self.__root
+        curr = root.next
+        time = self.__timer()
+        count = len(self.__links)
+        while curr is not root and curr.expire < time:
+            count -= 1
+            curr = curr.next
+        return count
+
+    def __setstate__(self, state):
+        self.__dict__.update(state)
+        root = self.__root
+        root.prev = root.next = root
+        for link in sorted(self.__links.values(), key=lambda obj: obj.expire):
+            link.next = root
+            link.prev = prev = root.prev
+            prev.next = root.prev = link
+        self.expire(self.__timer())
+
+    def __repr__(self, cache_repr=Cache.__repr__):
+        with self.__timer as time:
+            self.expire(time)
+            return cache_repr(self)
+
+    @property
+    def currsize(self):
+        with self.__timer as time:
+            self.expire(time)
+            return super(TTLCache, self).currsize
+
+    @property
+    def timer(self):
+        """The timer function used by the cache."""
+        return self.__timer
+
+    @property
+    def ttl(self):
+        """The time-to-live value of the cache's items."""
+        return self.__ttl
+
+    def expire(self, time=None):
+        """Remove expired items from the cache."""
+        if time is None:
+            time = self.__timer()
+        root = self.__root
+        curr = root.next
+        links = self.__links
+        cache_delitem = Cache.__delitem__
+        while curr is not root and curr.expire < time:
+            cache_delitem(self, curr.key)
+            del links[curr.key]
+            next = curr.next
+            curr.unlink()
+            curr = next
+
+    def clear(self):
+        with self.__timer as time:
+            self.expire(time)
+            Cache.clear(self)
+
+    def get(self, *args, **kwargs):
+        with self.__timer:
+            return Cache.get(self, *args, **kwargs)
+
+    def pop(self, *args, **kwargs):
+        with self.__timer:
+            return Cache.pop(self, *args, **kwargs)
+
+    def setdefault(self, *args, **kwargs):
+        with self.__timer:
+            return Cache.setdefault(self, *args, **kwargs)
+
+    def popitem(self):
+        """Remove and return the `(key, value)` pair least recently used that
+        has not already expired.
+
+        """
+        with self.__timer as time:
+            self.expire(time)
+            try:
+                key = next(iter(self.__links))
+            except StopIteration:
+                msg = '%s is empty' % self.__class__.__name__
+                raise KeyError(msg) from None
+            else:
+                return (key, self.pop(key))
+
+    def __getlink(self, key):
+        value = self.__links[key]
+        self.__links.move_to_end(key)
+        return value