Improve the Cursor using deque PYTHON-351

Tested faster than using pop and manually using a pointer

Author: rozza

pymongo/cursor.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 """Cursor class to iterate over Mongo query results."""
+from collections import deque
 
 from bson.code import Code
 from bson.son import SON
@@ -120,7 +121,7 @@ def __init__(self, collection, spec=None, fields=None, skip=0, limit=0,
  self.__uuid_subtype = _uuid_subtype or collection.uuid_subtype
  self.__query_flags = 0
 
- self.__data = []
+ self.__data = deque()
  self.__connection_id = None
  self.__retrieved = 0
  self.__killed = False
@@ -151,7 +152,7 @@ def rewind(self):
  be sent to the server, even if the resultant data has already been
  retrieved by this cursor.
  """
- self.__data = []
+ self.__data = deque()
  self.__id = None
  self.__connection_id = None
  self.__retrieved = 0
@@ -697,7 +698,7 @@ def __send_message(self, message):
  response['starting_from'], self.__retrieved))
 
  self.__retrieved += response["number_returned"]
- self.__data = response["data"]
+ self.__data = deque(response["data"])
 
  if self.__limit and self.__id and self.__limit <= self.__retrieved:
  self.__die()
@@ -775,9 +776,10 @@ def next(self):
  db = self.__collection.database
  if len(self.__data) or self._refresh():
  if self.__manipulate:
- return db._fix_outgoing(self.__data.pop(0), self.__collection)
+ return db._fix_outgoing(self.__data.popleft(),
+ self.__collection)
  else:
- return self.__data.pop(0)
+ return self.__data.popleft()
  else:
  raise StopIteration
 
@@ -786,4 +788,3 @@ def __enter__(self):
 
  def __exit__(self, exc_type, exc_val, exc_tb):
  self.__die()
-