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

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+# Copyright 2016-present 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.
+
+"""An implementation of RFC4013 SASLprep."""
+
+from bson.py3compat import text_type as _text_type
+
+try:
+    import stringprep
+except ImportError:
+    HAVE_STRINGPREP = False
+    def saslprep(data):
+        """SASLprep dummy"""
+        if isinstance(data, _text_type):
+            raise TypeError(
+                "The stringprep module is not available. Usernames and "
+                "passwords must be ASCII strings.")
+        return data
+else:
+    HAVE_STRINGPREP = True
+    import unicodedata
+    # RFC4013 section 2.3 prohibited output.
+    _PROHIBITED = (
+        # A strict reading of RFC 4013 requires table c12 here, but
+        # characters from it are mapped to SPACE in the Map step. Can
+        # normalization reintroduce them somehow?
+        stringprep.in_table_c12,
+        stringprep.in_table_c21_c22,
+        stringprep.in_table_c3,
+        stringprep.in_table_c4,
+        stringprep.in_table_c5,
+        stringprep.in_table_c6,
+        stringprep.in_table_c7,
+        stringprep.in_table_c8,
+        stringprep.in_table_c9)
+
+    def saslprep(data, prohibit_unassigned_code_points=True):
+        """An implementation of RFC4013 SASLprep.
+
+        :Parameters:
+          - `data`: The string to SASLprep. Unicode strings
+            (python 2.x unicode, 3.x str) are supported. Byte strings
+            (python 2.x str, 3.x bytes) are ignored.
+          - `prohibit_unassigned_code_points`: True / False. RFC 3454
+            and RFCs for various SASL mechanisms distinguish between
+            `queries` (unassigned code points allowed) and
+            `stored strings` (unassigned code points prohibited). Defaults
+            to ``True`` (unassigned code points are prohibited).
+
+        :Returns:
+        The SASLprep'ed version of `data`.
+        """
+        if not isinstance(data, _text_type):
+            return data
+
+        if prohibit_unassigned_code_points:
+            prohibited = _PROHIBITED + (stringprep.in_table_a1,)
+        else:
+            prohibited = _PROHIBITED
+
+        # RFC3454 section 2, step 1 - Map
+        # RFC4013 section 2.1 mappings
+        # Map Non-ASCII space characters to SPACE (U+0020). Map
+        # commonly mapped to nothing characters to, well, nothing.
+        in_table_c12 = stringprep.in_table_c12
+        in_table_b1 = stringprep.in_table_b1
+        data = u"".join(
+            [u"\u0020" if in_table_c12(elt) else elt
+             for elt in data if not in_table_b1(elt)])
+
+        # RFC3454 section 2, step 2 - Normalize
+        # RFC4013 section 2.2 normalization
+        data = unicodedata.ucd_3_2_0.normalize('NFKC', data)
+
+        in_table_d1 = stringprep.in_table_d1
+        if in_table_d1(data[0]):
+            if not in_table_d1(data[-1]):
+                # RFC3454, Section 6, #3. If a string contains any
+                # RandALCat character, the first and last characters
+                # MUST be RandALCat characters.
+                raise ValueError("SASLprep: failed bidirectional check")
+            # RFC3454, Section 6, #2. If a string contains any RandALCat
+            # character, it MUST NOT contain any LCat character.
+            prohibited = prohibited + (stringprep.in_table_d2,)
+        else:
+            # RFC3454, Section 6, #3. Following the logic of #3, if
+            # the first character is not a RandALCat, no other character
+            # can be either.
+            prohibited = prohibited + (in_table_d1,)
+
+        # RFC3454 section 2, step 3 and 4 - Prohibit and check bidi
+        for char in data:
+            if any(in_table(char) for in_table in prohibited):
+                raise ValueError(
+                    "SASLprep: failed prohibited character check")
+
+        return data