1 files changed, 199 insertions, 0 deletions
diff --git a/urllib3/_collections.py b/urllib3/_collections.py
new file mode 100644
index 0000000..d77ebb8
--- /dev/null
+++ b/urllib3/_collections.py
@@ -0,0 +1,199 @@
+from collections import Mapping, MutableMapping
+try:
+    from threading import RLock
+except ImportError: # Platform-specific: No threads available
+    class RLock:
+        def __enter__(self):
+            pass
+
+        def __exit__(self, exc_type, exc_value, traceback):
+            pass
+
+
+try: # Python 2.7+
+    from collections import OrderedDict
+except ImportError:
+    from .packages.ordered_dict import OrderedDict
+from .packages.six import itervalues
+
+
+__all__ = ['RecentlyUsedContainer', 'HTTPHeaderDict']
+
+
+_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 = RLock()
+
+    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()
+
+
+class HTTPHeaderDict(MutableMapping):
+    """
+    :param headers:
+        An iterable of field-value pairs. Must not contain multiple field names
+        when compared case-insensitively.
+
+    :param kwargs:
+        Additional field-value pairs to pass in to ``dict.update``.
+
+    A ``dict`` like container for storing HTTP Headers.
+
+    Field names are stored and compared case-insensitively in compliance with
+    RFC 7230. Iteration provides the first case-sensitive key seen for each
+    case-insensitive pair.
+
+    Using ``__setitem__`` syntax overwrites fields that compare equal
+    case-insensitively in order to maintain ``dict``'s api. For fields that
+    compare equal, instead create a new ``HTTPHeaderDict`` and use ``.add``
+    in a loop.
+
+    If multiple fields that are equal case-insensitively are passed to the
+    constructor or ``.update``, the behavior is undefined and some will be
+    lost.
+
+    >>> headers = HTTPHeaderDict()
+    >>> headers.add('Set-Cookie', 'foo=bar')
+    >>> headers.add('set-cookie', 'baz=quxx')
+    >>> headers['content-length'] = '7'
+    >>> headers['SET-cookie']
+    'foo=bar, baz=quxx'
+    >>> headers['Content-Length']
+    '7'
+
+    If you want to access the raw headers with their original casing
+    for debugging purposes you can access the private ``._data`` attribute
+    which is a normal python ``dict`` that maps the case-insensitive key to a
+    list of tuples stored as (case-sensitive-original-name, value). Using the
+    structure from above as our example:
+
+    >>> headers._data
+    {'set-cookie': [('Set-Cookie', 'foo=bar'), ('set-cookie', 'baz=quxx')],
+    'content-length': [('content-length', '7')]}
+    """
+
+    def __init__(self, headers=None, **kwargs):
+        self._data = {}
+        if headers is None:
+            headers = {}
+        self.update(headers, **kwargs)
+
+    def add(self, key, value):
+        """Adds a (name, value) pair, doesn't overwrite the value if it already
+        exists.
+
+        >>> headers = HTTPHeaderDict(foo='bar')
+        >>> headers.add('Foo', 'baz')
+        >>> headers['foo']
+        'bar, baz'
+        """
+        self._data.setdefault(key.lower(), []).append((key, value))
+
+    def getlist(self, key):
+        """Returns a list of all the values for the named field. Returns an
+        empty list if the key doesn't exist."""
+        return self[key].split(', ') if key in self else []
+
+    def copy(self):
+        h = HTTPHeaderDict()
+        for key in self._data:
+            for rawkey, value in self._data[key]:
+                h.add(rawkey, value)
+        return h
+
+    def __eq__(self, other):
+        if not isinstance(other, Mapping):
+            return False
+        other = HTTPHeaderDict(other)
+        return dict((k1, self[k1]) for k1 in self._data) == \
+                dict((k2, other[k2]) for k2 in other._data)
+
+    def __getitem__(self, key):
+        values = self._data[key.lower()]
+        return ', '.join(value[1] for value in values)
+
+    def __setitem__(self, key, value):
+        self._data[key.lower()] = [(key, value)]
+
+    def __delitem__(self, key):
+        del self._data[key.lower()]
+
+    def __len__(self):
+        return len(self._data)
+
+    def __iter__(self):
+        for headers in itervalues(self._data):
+            yield headers[0][0]
+
+    def __repr__(self):
+        return '%s(%r)' % (self.__class__.__name__, dict(self.items()))