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diff --git a/python/gevent/local.py b/python/gevent/local.py
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+"""
+Greenlet-local objects.
+
+This module is based on `_threading_local.py`__ from the standard
+library of Python 3.4.
+
+__ https://github.com/python/cpython/blob/3.4/Lib/_threading_local.py
+
+Greenlet-local objects support the management of greenlet-local data.
+If you have data that you want to be local to a greenlet, simply create
+a greenlet-local object and use its attributes:
+
+  >>> mydata = local()
+  >>> mydata.number = 42
+  >>> mydata.number
+  42
+
+You can also access the local-object's dictionary:
+
+  >>> mydata.__dict__
+  {'number': 42}
+  >>> mydata.__dict__.setdefault('widgets', [])
+  []
+  >>> mydata.widgets
+  []
+
+What's important about greenlet-local objects is that their data are
+local to a greenlet. If we access the data in a different greenlet:
+
+  >>> log = []
+  >>> def f():
+  ...     items = list(mydata.__dict__.items())
+  ...     items.sort()
+  ...     log.append(items)
+  ...     mydata.number = 11
+  ...     log.append(mydata.number)
+  >>> greenlet = gevent.spawn(f)
+  >>> greenlet.join()
+  >>> log
+  [[], 11]
+
+we get different data.  Furthermore, changes made in the other greenlet
+don't affect data seen in this greenlet:
+
+  >>> mydata.number
+  42
+
+Of course, values you get from a local object, including a __dict__
+attribute, are for whatever greenlet was current at the time the
+attribute was read.  For that reason, you generally don't want to save
+these values across greenlets, as they apply only to the greenlet they
+came from.
+
+You can create custom local objects by subclassing the local class:
+
+  >>> class MyLocal(local):
+  ...     number = 2
+  ...     initialized = False
+  ...     def __init__(self, **kw):
+  ...         if self.initialized:
+  ...             raise SystemError('__init__ called too many times')
+  ...         self.initialized = True
+  ...         self.__dict__.update(kw)
+  ...     def squared(self):
+  ...         return self.number ** 2
+
+This can be useful to support default values, methods and
+initialization.  Note that if you define an __init__ method, it will be
+called each time the local object is used in a separate greenlet.  This
+is necessary to initialize each greenlet's dictionary.
+
+Now if we create a local object:
+
+  >>> mydata = MyLocal(color='red')
+
+Now we have a default number:
+
+  >>> mydata.number
+  2
+
+an initial color:
+
+  >>> mydata.color
+  'red'
+  >>> del mydata.color
+
+And a method that operates on the data:
+
+  >>> mydata.squared()
+  4
+
+As before, we can access the data in a separate greenlet:
+
+  >>> log = []
+  >>> greenlet = gevent.spawn(f)
+  >>> greenlet.join()
+  >>> log
+  [[('color', 'red'), ('initialized', True)], 11]
+
+without affecting this greenlet's data:
+
+  >>> mydata.number
+  2
+  >>> mydata.color
+  Traceback (most recent call last):
+  ...
+  AttributeError: 'MyLocal' object has no attribute 'color'
+
+Note that subclasses can define slots, but they are not greenlet
+local. They are shared across greenlets::
+
+  >>> class MyLocal(local):
+  ...     __slots__ = 'number'
+
+  >>> mydata = MyLocal()
+  >>> mydata.number = 42
+  >>> mydata.color = 'red'
+
+So, the separate greenlet:
+
+  >>> greenlet = gevent.spawn(f)
+  >>> greenlet.join()
+
+affects what we see:
+
+  >>> mydata.number
+  11
+
+>>> del mydata
+
+.. versionchanged:: 1.1a2
+   Update the implementation to match Python 3.4 instead of Python 2.5.
+   This results in locals being eligible for garbage collection as soon
+   as their greenlet exits.
+
+"""
+
+from copy import copy
+from weakref import ref
+from contextlib import contextmanager
+from gevent.hub import getcurrent
+from gevent._compat import PYPY
+from gevent.lock import RLock
+
+__all__ = ["local"]
+
+
+class _wrefdict(dict):
+    """A dict that can be weak referenced"""
+
+
+class _localimpl(object):
+    """A class managing thread-local dicts"""
+    __slots__ = 'key', 'dicts', 'localargs', 'locallock', '__weakref__'
+
+    def __init__(self):
+        # The key used in the Thread objects' attribute dicts.
+        # We keep it a string for speed but make it unlikely to clash with
+        # a "real" attribute.
+        self.key = '_threading_local._localimpl.' + str(id(self))
+        # { id(Thread) -> (ref(Thread), thread-local dict) }
+        self.dicts = _wrefdict()
+
+    def get_dict(self):
+        """Return the dict for the current thread. Raises KeyError if none
+        defined."""
+        thread = getcurrent()
+        return self.dicts[id(thread)][1]
+
+    def create_dict(self):
+        """Create a new dict for the current thread, and return it."""
+        localdict = {}
+        key = self.key
+        thread = getcurrent()
+        idt = id(thread)
+
+        # If we are working with a gevent.greenlet.Greenlet, we can
+        # pro-actively clear out with a link. Use rawlink to avoid
+        # spawning any more greenlets
+        try:
+            rawlink = thread.rawlink
+        except AttributeError:
+            # Otherwise we need to do it with weak refs
+            def local_deleted(_, key=key):
+                # When the localimpl is deleted, remove the thread attribute.
+                thread = wrthread()
+                if thread is not None:
+                    del thread.__dict__[key]
+
+            def thread_deleted(_, idt=idt):
+                # When the thread is deleted, remove the local dict.
+                # Note that this is suboptimal if the thread object gets
+                # caught in a reference loop. We would like to be called
+                # as soon as the OS-level thread ends instead.
+                _local = wrlocal()
+                if _local is not None:
+                    _local.dicts.pop(idt, None)
+            wrlocal = ref(self, local_deleted)
+            wrthread = ref(thread, thread_deleted)
+            thread.__dict__[key] = wrlocal
+        else:
+            wrdicts = ref(self.dicts)
+
+            def clear(_):
+                dicts = wrdicts()
+                if dicts:
+                    dicts.pop(idt, None)
+            rawlink(clear)
+            wrthread = None
+
+        self.dicts[idt] = wrthread, localdict
+        return localdict
+
+
+@contextmanager
+def _patch(self):
+    impl = object.__getattribute__(self, '_local__impl')
+    orig_dct = object.__getattribute__(self, '__dict__')
+    try:
+        dct = impl.get_dict()
+    except KeyError:
+        # it's OK to acquire the lock here and not earlier, because the above code won't switch out
+        # however, subclassed __init__ might switch, so we do need to acquire the lock here
+        dct = impl.create_dict()
+        args, kw = impl.localargs
+        with impl.locallock:
+            self.__init__(*args, **kw)
+    with impl.locallock:
+        object.__setattr__(self, '__dict__', dct)
+        yield
+        object.__setattr__(self, '__dict__', orig_dct)
+
+
+class local(object):
+    """
+    An object whose attributes are greenlet-local.
+    """
+    __slots__ = '_local__impl', '__dict__'
+
+    def __new__(cls, *args, **kw):
+        if args or kw:
+            if (PYPY and cls.__init__ == object.__init__) or (not PYPY and cls.__init__ is object.__init__):
+                raise TypeError("Initialization arguments are not supported")
+        self = object.__new__(cls)
+        impl = _localimpl()
+        impl.localargs = (args, kw)
+        impl.locallock = RLock()
+        object.__setattr__(self, '_local__impl', impl)
+        # We need to create the thread dict in anticipation of
+        # __init__ being called, to make sure we don't call it
+        # again ourselves.
+        impl.create_dict()
+        return self
+
+    def __getattribute__(self, name):
+        with _patch(self):
+            return object.__getattribute__(self, name)
+
+    def __setattr__(self, name, value):
+        if name == '__dict__':
+            raise AttributeError(
+                "%r object attribute '__dict__' is read-only"
+                % self.__class__.__name__)
+        with _patch(self):
+            return object.__setattr__(self, name, value)
+
+    def __delattr__(self, name):
+        if name == '__dict__':
+            raise AttributeError(
+                "%r object attribute '__dict__' is read-only"
+                % self.__class__.__name__)
+        with _patch(self):
+            return object.__delattr__(self, name)
+
+    def __copy__(self):
+        impl = object.__getattribute__(self, '_local__impl')
+        current = getcurrent()
+        currentId = id(current)
+        d = impl.get_dict()
+        duplicate = copy(d)
+
+        cls = type(self)
+        if (PYPY and cls.__init__ != object.__init__) or (not PYPY and cls.__init__ is not object.__init__):
+            args, kw = impl.localargs
+            instance = cls(*args, **kw)
+        else:
+            instance = cls()
+
+        new_impl = object.__getattribute__(instance, '_local__impl')
+        tpl = new_impl.dicts[currentId]
+        new_impl.dicts[currentId] = (tpl[0], duplicate)
+
+        return instance