Initial commit

venv/lib/python3.8/site-packages/pymongo/read_concern.py

@@ -0,0 +1,76 @@
+# Copyright 2015 MongoDB, 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.
+
+"""Tools for working with read concerns."""
+
+from bson.py3compat import string_type
+
+
+class ReadConcern(object):
+    """ReadConcern
+
+    :Parameters:
+        - `level`: (string) The read concern level specifies the level of
+          isolation for read operations.  For example, a read operation using a
+          read concern level of ``majority`` will only return data that has been
+          written to a majority of nodes. If the level is left unspecified, the
+          server default will be used.
+
+    .. versionadded:: 3.2
+
+    """
+
+    def __init__(self, level=None):
+        if level is None or isinstance(level, string_type):
+            self.__level = level
+        else:
+            raise TypeError(
+                'level must be a string or None.')
+
+    @property
+    def level(self):
+        """The read concern level."""
+        return self.__level
+
+    @property
+    def ok_for_legacy(self):
+        """Return ``True`` if this read concern is compatible with
+        old wire protocol versions."""
+        return self.level is None or self.level == 'local'
+
+    @property
+    def document(self):
+        """The document representation of this read concern.
+
+        .. note::
+          :class:`ReadConcern` is immutable. Mutating the value of
+          :attr:`document` does not mutate this :class:`ReadConcern`.
+        """
+        doc = {}
+        if self.__level:
+            doc['level'] = self.level
+        return doc
+
+    def __eq__(self, other):
+        if isinstance(other, ReadConcern):
+            return self.document == other.document
+        return NotImplemented
+
+    def __repr__(self):
+        if self.level:
+            return 'ReadConcern(%s)' % self.level
+        return 'ReadConcern()'
+
+
+DEFAULT_READ_CONCERN = ReadConcern()