/usr/lib/python3/dist-packages/pymongo/command_cursor.py is in python3-pymongo 2.7.2-1.
This file is owned by root:root, with mode 0o644.
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#
# 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.
"""CommandCursor class to iterate over command results."""
from collections import deque
from pymongo import helpers, message
from pymongo.errors import AutoReconnect, CursorNotFound
class CommandCursor(object):
"""A cursor / iterator over command cursors.
"""
def __init__(self, collection, cursor_info,
conn_id, compile_re=True, retrieved=0):
"""Create a new command cursor.
"""
self.__collection = collection
self.__id = cursor_info['id']
self.__conn_id = conn_id
self.__data = deque(cursor_info['firstBatch'])
self.__decode_opts = (
collection.database.connection.document_class,
collection.database.connection.tz_aware,
collection.uuid_subtype,
compile_re
)
self.__retrieved = retrieved
self.__batch_size = 0
self.__killed = False
def __del__(self):
if self.__id and not self.__killed:
self.__die()
def __die(self):
"""Closes this cursor.
"""
if self.__id and not self.__killed:
client = self.__collection.database.connection
if self.__conn_id is not None:
client.close_cursor(self.__id, self.__conn_id)
else:
client.close_cursor(self.__id)
self.__killed = True
def close(self):
"""Explicitly close / kill this cursor. Required for PyPy, Jython and
other Python implementations that don't use reference counting
garbage collection.
"""
self.__die()
def batch_size(self, batch_size):
"""Limits the number of documents returned in one batch. Each batch
requires a round trip to the server. It can be adjusted to optimize
performance and limit data transfer.
.. note:: batch_size can not override MongoDB's internal limits on the
amount of data it will return to the client in a single batch (i.e
if you set batch size to 1,000,000,000, MongoDB will currently only
return 4-16MB of results per batch).
Raises :exc:`TypeError` if `batch_size` is not an integer.
Raises :exc:`ValueError` if `batch_size` is less than ``0``.
:Parameters:
- `batch_size`: The size of each batch of results requested.
"""
if not isinstance(batch_size, int):
raise TypeError("batch_size must be an integer")
if batch_size < 0:
raise ValueError("batch_size must be >= 0")
self.__batch_size = batch_size == 1 and 2 or batch_size
return self
def __send_message(self, msg):
"""Send a getmore message and handle the response.
"""
client = self.__collection.database.connection
try:
res = client._send_message_with_response(
msg, _connection_to_use=self.__conn_id)
self.__conn_id, (response, dummy0, dummy1) = res
except AutoReconnect:
# Don't try to send kill cursors on another socket
# or to another server. It can cause a _pinValue
# assertion on some server releases if we get here
# due to a socket timeout.
self.__killed = True
raise
try:
response = helpers._unpack_response(response,
self.__id,
*self.__decode_opts)
except CursorNotFound:
self.__killed = True
raise
except AutoReconnect:
# Don't send kill cursors to another server after a "not master"
# error. It's completely pointless.
self.__killed = True
client.disconnect()
raise
self.__id = response["cursor_id"]
assert response["starting_from"] == self.__retrieved, (
"Result batch started from %s, expected %s" % (
response['starting_from'], self.__retrieved))
self.__retrieved += response["number_returned"]
self.__data = deque(response["data"])
def _refresh(self):
"""Refreshes the cursor with more data from the server.
Returns the length of self.__data after refresh. Will exit early if
self.__data is already non-empty. Raises OperationFailure when the
cursor cannot be refreshed due to an error on the query.
"""
if len(self.__data) or self.__killed:
return len(self.__data)
if self.__id: # Get More
self.__send_message(
message.get_more(self.__collection.full_name,
self.__batch_size, self.__id))
else: # Cursor id is zero nothing else to return
self.__killed = True
return len(self.__data)
@property
def alive(self):
"""Does this cursor have the potential to return more data?"""
return bool(len(self.__data) or (not self.__killed))
@property
def cursor_id(self):
"""Returns the id of the cursor."""
return self.__id
def __iter__(self):
return self
def __next__(self):
"""Advance the cursor.
"""
if len(self.__data) or self._refresh():
coll = self.__collection
return coll.database._fix_incoming(self.__data.popleft(), coll)
else:
raise StopIteration
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.__die()
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