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diff --git a/google_appengine/google/appengine/api/queueinfo.py b/google_appengine/google/appengine/api/queueinfo.py
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+#!/usr/bin/env python
+#
+# Copyright 2007 Google Inc.
+#
+# 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.
+#
+
+"""QueueInfo tools.
+
+A library for working with QueueInfo records, describing task queue entries
+for an application. Supports loading the records from queue.yaml.
+
+A queue has two required parameters and one optional one. The required
+parameters are 'name' (must be unique for an appid) and 'rate' (the rate
+at which jobs in the queue are run). There is an optional parameter
+'bucket_size' that will allow tokens to be 'saved up' (for more on the
+algorithm, see http://en.wikipedia.org/wiki/Token_Bucket). rate is expressed
+as number/unit, with number being an int or a float, and unit being one of
+'s' (seconds), 'm' (minutes), 'h' (hours) or 'd' (days). bucket_size is
+an integer.
+
+An example of the use of bucket_size rate: the free email quota is 2000/d,
+and the maximum you can send in a single minute is 11. So we can define a
+queue for sending email like this:
+
+queue:
+- name: mail_queue
+  rate: 2000/d
+  bucket_size: 10
+
+If this queue had been idle for a while before some jobs were submitted to it,
+the first 10 jobs submitted would be run immediately, then subsequent ones
+would be run once every 40s or so. The limit of 2000 per day would still apply.
+"""
+
+
+
+from google.appengine.api import validation
+from google.appengine.api import yaml_builder
+from google.appengine.api import yaml_listener
+from google.appengine.api import yaml_object
+
+_NAME_REGEX = r'^[A-Za-z0-9-]{0,499}$'
+_RATE_REGEX = r'^(0|[0-9]+(\.[0-9]*)?/[smhd])'
+
+QUEUE = 'queue'
+
+NAME = 'name'
+RATE = 'rate'
+BUCKET_SIZE = 'bucket_size'
+
+
+class MalformedQueueConfiguration(Exception):
+  """Configuration file for Task Queue is malformed."""
+
+
+class QueueEntry(validation.Validated):
+  """A queue entry describes a single task queue."""
+  ATTRIBUTES = {
+      NAME: _NAME_REGEX,
+      RATE: _RATE_REGEX,
+      BUCKET_SIZE: validation.Optional(validation.TYPE_INT),
+  }
+
+
+class QueueInfoExternal(validation.Validated):
+  """QueueInfoExternal describes all queue entries for an application."""
+  ATTRIBUTES = {
+      QUEUE: validation.Optional(validation.Repeated(QueueEntry))
+  }
+
+
+def LoadSingleQueue(queue_info):
+  """Load a queue.yaml file or string and return a QueueInfoExternal object.
+
+  Args:
+    queue_info: the contents of a queue.yaml file, as a string.
+
+  Returns:
+    A QueueInfoExternal object.
+  """
+  builder = yaml_object.ObjectBuilder(QueueInfoExternal)
+  handler = yaml_builder.BuilderHandler(builder)
+  listener = yaml_listener.EventListener(handler)
+  listener.Parse(queue_info)
+
+  queue_info = handler.GetResults()
+  if len(queue_info) < 1:
+    raise MalformedQueueConfiguration('Empty queue configuration.')
+  if len(queue_info) > 1:
+    raise MalformedQueueConfiguration('Multiple queue: sections '
+                                      'in configuration.')
+  return queue_info[0]
+
+
+def ParseRate(rate):
+  """Parses a rate string in the form number/unit, or the literal 0.
+
+  The unit is one of s (seconds), m (minutes), h (hours) or d (days).
+
+  Args:
+    rate: the rate string.
+
+  Returns:
+    a floating point number representing the rate/second.
+
+  Raises:
+    MalformedQueueConfiguration: if the rate is invalid
+  """
+  if rate == "0":
+    return 0.0
+  elements = rate.split('/')
+  if len(elements) != 2:
+    raise MalformedQueueConfiguration('Rate "%s" is invalid.' % rate)
+  number, unit = elements
+  try:
+    number = float(number)
+  except ValueError:
+    raise MalformedQueueConfiguration('Rate "%s" is invalid:'
+                                          ' "%s" is not a number.' %
+                                          (rate, number))
+  if unit not in 'smhd':
+    raise MalformedQueueConfiguration('Rate "%s" is invalid:'
+                                          ' "%s" is not one of s, m, h, d.' %
+                                          (rate, unit))
+  if unit == 's':
+    return number
+  if unit == 'm':
+    return number/60
+  if unit == 'h':
+    return number/(60 * 60)
+  if unit == 'd':
+    return number/(24 * 60 * 60)