Add google-endpoints to third_party/.

third_party/google-endpoints/cachetools/func.py

+"""`functools.lru_cache` compatible memoizing function decorators."""
+
+import collections
+import functools
+import random
+import time
+import warnings
+
+try:
+    from threading import RLock
+except ImportError:
+    from dummy_threading import RLock
+
+from .keys import hashkey, typedkey
+
+__all__ = ('lfu_cache', 'lru_cache', 'rr_cache', 'ttl_cache')
+
+
+class _NLock:
+    def __enter__(self):
+        pass
+
+    def __exit__(self, *exc):
+        pass
+
+_CacheInfo = collections.namedtuple('CacheInfo', [
+    'hits', 'misses', 'maxsize', 'currsize'
+])
+
+_marker = object()
+
+
+def _deprecated(message, level=2):
+    warnings.warn('%s is deprecated' % message, DeprecationWarning, level)
+
+
+def _cache(cache, typed=False, context=_marker):
+    def decorator(func):
+        key = typedkey if typed else hashkey
+        if context is _marker:
+            lock = RLock()
+        elif context is None:
+            lock = _NLock()
+        else:
+            lock = context()
+        stats = [0, 0]
+
+        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]
+
+        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
+        functools.update_wrapper(wrapper, func)
+        if not hasattr(wrapper, '__wrapped__'):
+            wrapper.__wrapped__ = func  # Python < 3.2
+        wrapper.cache_info = cache_info
+        wrapper.cache_clear = cache_clear
+        return wrapper
+    return decorator
+
+
+def lfu_cache(maxsize=128, typed=False, getsizeof=None, lock=_marker):
+    """Decorator to wrap a function with a memoizing callable that saves
+    up to `maxsize` results based on a Least Frequently Used (LFU)
+    algorithm.
+
+    """
+    from .lfu import LFUCache
+    if lock is not _marker:
+        _deprecated("Passing 'lock' to lfu_cache()", 3)
+    return _cache(LFUCache(maxsize, getsizeof), typed, lock)
+
+
+def lru_cache(maxsize=128, typed=False, getsizeof=None, lock=_marker):
+    """Decorator to wrap a function with a memoizing callable that saves
+    up to `maxsize` results based on a Least Recently Used (LRU)
+    algorithm.
+
+    """
+    from .lru import LRUCache
+    if lock is not _marker:
+        _deprecated("Passing 'lock' to lru_cache()", 3)
+    return _cache(LRUCache(maxsize, getsizeof), typed, lock)
+
+
+def rr_cache(maxsize=128, choice=random.choice, typed=False, getsizeof=None,
+             lock=_marker):
+    """Decorator to wrap a function with a memoizing callable that saves
+    up to `maxsize` results based on a Random Replacement (RR)
+    algorithm.
+
+    """
+    from .rr import RRCache
+    if lock is not _marker:
+        _deprecated("Passing 'lock' to rr_cache()", 3)
+    return _cache(RRCache(maxsize, choice, getsizeof), typed, lock)
+
+
+def ttl_cache(maxsize=128, ttl=600, timer=time.time, typed=False,
+              getsizeof=None, lock=_marker):
+    """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.
+    """
+    from .ttl import TTLCache
+    if lock is not _marker:
+        _deprecated("Passing 'lock' to ttl_cache()", 3)
+    return _cache(TTLCache(maxsize, ttl, timer, getsizeof), typed, lock)