Add google-endpoints to third_party/.

third_party/google-endpoints/future/builtins/newnext.py

+'''
+This module provides a newnext() function in Python 2 that mimics the
+behaviour of ``next()`` in Python 3, falling back to Python 2's behaviour for
+compatibility if this fails.
+
+``newnext(iterator)`` calls the iterator's ``__next__()`` method if it exists. If this
+doesn't exist, it falls back to calling a ``next()`` method.
+
+For example:
+
+    >>> class Odds(object):
+    ...     def __init__(self, start=1):
+    ...         self.value = start - 2
+    ...     def __next__(self):                 # note the Py3 interface
+    ...         self.value += 2
+    ...         return self.value
+    ...     def __iter__(self):
+    ...         return self
+    ...
+    >>> iterator = Odds()
+    >>> next(iterator)
+    1
+    >>> next(iterator)
+    3
+
+If you are defining your own custom iterator class as above, it is preferable
+to explicitly decorate the class with the @implements_iterator decorator from
+``future.utils`` as follows:
+
+    >>> @implements_iterator
+    ... class Odds(object):
+    ...     # etc
+    ...     pass
+
+This next() function is primarily for consuming iterators defined in Python 3
+code elsewhere that we would like to run on Python 2 or 3.
+'''
+
+_builtin_next = next
+
+_SENTINEL = object()
+
+def newnext(iterator, default=_SENTINEL):
+    """
+    next(iterator[, default])
+    
+    Return the next item from the iterator. If default is given and the iterator
+    is exhausted, it is returned instead of raising StopIteration.
+    """
+
+    # args = []
+    # if default is not _SENTINEL:
+    #     args.append(default)
+    try:
+        try:
+            return iterator.__next__()
+        except AttributeError:
+            try:
+                return iterator.next()
+            except AttributeError:
+                raise TypeError("'{0}' object is not an iterator".format(
+                                           iterator.__class__.__name__))
+    except StopIteration as e:
+        if default is _SENTINEL:
+            raise e
+        else:
+            return default
+
+
+__all__ = ['newnext']
+