Add 'requests' library to third_party.

third_party/requests/packages/urllib3/_collections.py

+# urllib3/_collections.py
+# Copyright 2008-2013 Andrey Petrov and contributors (see CONTRIBUTORS.txt)
+#
+# This module is part of urllib3 and is released under
+# the MIT License: http://www.opensource.org/licenses/mit-license.php
+
+from collections import MutableMapping
+from threading import Lock
+
+try: # Python 2.7+
+    from collections import OrderedDict
+except ImportError:
+    from .packages.ordered_dict import OrderedDict
+
+
+__all__ = ['RecentlyUsedContainer']
+
+
+_Null = object()
+
+
+class RecentlyUsedContainer(MutableMapping):
+    """
+    Provides a thread-safe dict-like container which maintains up to
+    ``maxsize`` keys while throwing away the least-recently-used keys beyond
+    ``maxsize``.
+
+    :param maxsize:
+        Maximum number of recent elements to retain.
+
+    :param dispose_func:
+        Every time an item is evicted from the container,
+        ``dispose_func(value)`` is called.  Callback which will get called
+    """
+
+    ContainerCls = OrderedDict
+
+    def __init__(self, maxsize=10, dispose_func=None):
+        self._maxsize = maxsize
+        self.dispose_func = dispose_func
+
+        self._container = self.ContainerCls()
+        self._lock = Lock()
+
+    def __getitem__(self, key):
+        # Re-insert the item, moving it to the end of the eviction line.
+        with self._lock:
+            item = self._container.pop(key)
+            self._container[key] = item
+            return item
+
+    def __setitem__(self, key, value):
+        evicted_value = _Null
+        with self._lock:
+            # Possibly evict the existing value of 'key'
+            evicted_value = self._container.get(key, _Null)
+            self._container[key] = value
+
+            # If we didn't evict an existing value, we might have to evict the
+            # least recently used item from the beginning of the container.
+            if len(self._container) > self._maxsize:
+                _key, evicted_value = self._container.popitem(last=False)
+
+        if self.dispose_func and evicted_value is not _Null:
+            self.dispose_func(evicted_value)
+
+    def __delitem__(self, key):
+        with self._lock:
+            value = self._container.pop(key)
+
+        if self.dispose_func:
+            self.dispose_func(value)
+
+    def __len__(self):
+        with self._lock:
+            return len(self._container)
+
+    def __iter__(self):
+        raise NotImplementedError('Iteration over this class is unlikely to be threadsafe.')
+
+    def clear(self):
+        with self._lock:
+            # Copy pointers to all values, then wipe the mapping
+            # under Python 2, this copies the list of values twice :-|
+            values = list(self._container.values())
+            self._container.clear()
+
+        if self.dispose_func:
+            for value in values:
+                self.dispose_func(value)
+
+    def keys(self):
+        with self._lock:
+            return self._container.keys()