Revert "Add gsutil 4.13 to telemetry/third_party"

tools/telemetry/third_party/gsutil/gslib/plurality_checkable_iterator.py

-# -*- coding: utf-8 -*-
-# Copyright 2012 Google Inc. All Rights Reserved.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-"""Iterator wrapper for checking wrapped iterator's emptiness or plurality."""
-
-# TODO: Here and elsewhere (wildcard_iterator, name_expansion), do not reference
-# __iter__ directly because it causes the first element to be instantiated.
-# Instead, implement __iter__ as a return self and implement the next() function
-# which returns (not yields) the values.  This necessitates that in the case
-# of the iterator classes, the iterator is used once per class instantiation
-# so that next() calls do not collide, but this semantic has been long-assumed
-# by the iterator classes for the use of __iter__ anyway.
-
-from __future__ import absolute_import
-
-import sys
-
-
-class PluralityCheckableIterator(object):
-  """Iterator wrapper class.
-
-    Allows you to check whether the wrapped iterator is empty and
-    whether it has more than 1 element. This iterator accepts three types of
-    values from the iterator it wraps:
-      1. A yielded element (this is the normal case).
-      2. A raised exception, which will be buffered and re-raised when it
-         is reached in this iterator.
-      3. A yielded tuple of (exception, stack trace), which will be buffered
-         and raised with it is reached in this iterator.
-  """
-
-  def __init__(self, it):
-    # Need to get the iterator function here so that we don't immediately
-    # instantiate the first element (which could raise an exception).
-    self.orig_iterator = it
-    self.base_iterator = None
-    self.head = []
-    self.underlying_iter_empty = False
-    # Populate first 2 elems into head so we can check whether iterator has
-    # more than 1 item.
-    for _ in range(0, 2):
-      self._PopulateHead()
-
-  def _PopulateHead(self):
-    if not self.underlying_iter_empty:
-      try:
-        if not self.base_iterator:
-          self.base_iterator = iter(self.orig_iterator)
-        e = self.base_iterator.next()
-        self.underlying_iter_empty = False
-        if isinstance(e, tuple) and isinstance(e[0], Exception):
-          self.head.append(('exception', e[0], e[1]))
-        else:
-          self.head.append(('element', e))
-      except StopIteration:
-        # Indicates we can no longer call next() on underlying iterator, but
-        # there could still be elements left to iterate in head.
-        self.underlying_iter_empty = True
-      except Exception, e:
-        # Buffer the exception and raise it when the element is accessed.
-        # Also, preserve the original stack trace, as the stack trace from
-        # within plurality_checkable_iterator.next is not very useful.
-        self.head.append(('exception', e, sys.exc_info()[2]))
-
-  def __iter__(self):
-    return self
-
-  def next(self):
-    # Backfill into head each time we pop an element so we can always check
-    # for emptiness and for HasPlurality().
-    while self.head:
-      self._PopulateHead()
-      item_tuple = self.head.pop(0)
-      if item_tuple[0] == 'element':
-        return item_tuple[1]
-      else:  # buffered exception
-        raise item_tuple[1].__class__, item_tuple[1], item_tuple[2]
-    raise StopIteration()
-
-  def IsEmpty(self):
-    return not self.head
-
-  def HasPlurality(self):
-    return len(self.head) > 1