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134 lines
4.5 KiB
134 lines
4.5 KiB
# Copyright 2013-present MongoDB, Inc. |
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# |
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# Licensed under the Apache License, Version 2.0 (the "License"); |
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# you may not use this file except in compliance with the License. |
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# You may obtain a copy of the License at |
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# |
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# http://www.apache.org/licenses/LICENSE-2.0 |
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# |
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# Unless required by applicable law or agreed to in writing, software |
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# distributed under the License is distributed on an "AS IS" BASIS, |
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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# See the License for the specific language governing permissions and |
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# limitations under the License. |
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"""Tools for representing MongoDB regular expressions.""" |
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import re |
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from typing import Any, Generic, Pattern, Type, TypeVar, Union |
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from bson._helpers import _getstate_slots, _setstate_slots |
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from bson.son import RE_TYPE |
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def str_flags_to_int(str_flags: str) -> int: |
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flags = 0 |
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if "i" in str_flags: |
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flags |= re.IGNORECASE |
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if "l" in str_flags: |
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flags |= re.LOCALE |
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if "m" in str_flags: |
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flags |= re.MULTILINE |
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if "s" in str_flags: |
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flags |= re.DOTALL |
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if "u" in str_flags: |
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flags |= re.UNICODE |
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if "x" in str_flags: |
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flags |= re.VERBOSE |
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return flags |
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_T = TypeVar("_T", str, bytes) |
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class Regex(Generic[_T]): |
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"""BSON regular expression data.""" |
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__slots__ = ("pattern", "flags") |
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__getstate__ = _getstate_slots |
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__setstate__ = _setstate_slots |
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_type_marker = 11 |
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@classmethod |
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def from_native(cls: Type["Regex"], regex: "Pattern[_T]") -> "Regex[_T]": |
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"""Convert a Python regular expression into a ``Regex`` instance. |
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Note that in Python 3, a regular expression compiled from a |
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:class:`str` has the ``re.UNICODE`` flag set. If it is undesirable |
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to store this flag in a BSON regular expression, unset it first:: |
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>>> pattern = re.compile('.*') |
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>>> regex = Regex.from_native(pattern) |
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>>> regex.flags ^= re.UNICODE |
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>>> db.collection.insert_one({'pattern': regex}) |
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:Parameters: |
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- `regex`: A regular expression object from ``re.compile()``. |
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.. warning:: |
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Python regular expressions use a different syntax and different |
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set of flags than MongoDB, which uses `PCRE`_. A regular |
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expression retrieved from the server may not compile in |
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Python, or may match a different set of strings in Python than |
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when used in a MongoDB query. |
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.. _PCRE: http://www.pcre.org/ |
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""" |
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if not isinstance(regex, RE_TYPE): |
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raise TypeError("regex must be a compiled regular expression, not %s" % type(regex)) |
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return Regex(regex.pattern, regex.flags) |
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def __init__(self, pattern: _T, flags: Union[str, int] = 0) -> None: |
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"""BSON regular expression data. |
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This class is useful to store and retrieve regular expressions that are |
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incompatible with Python's regular expression dialect. |
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:Parameters: |
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- `pattern`: string |
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- `flags`: (optional) an integer bitmask, or a string of flag |
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characters like "im" for IGNORECASE and MULTILINE |
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""" |
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if not isinstance(pattern, (str, bytes)): |
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raise TypeError("pattern must be a string, not %s" % type(pattern)) |
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self.pattern: _T = pattern |
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if isinstance(flags, str): |
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self.flags = str_flags_to_int(flags) |
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elif isinstance(flags, int): |
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self.flags = flags |
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else: |
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raise TypeError("flags must be a string or int, not %s" % type(flags)) |
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def __eq__(self, other: Any) -> bool: |
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if isinstance(other, Regex): |
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return self.pattern == other.pattern and self.flags == other.flags |
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else: |
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return NotImplemented |
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__hash__ = None # type: ignore |
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def __ne__(self, other: Any) -> bool: |
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return not self == other |
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def __repr__(self) -> str: |
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return f"Regex({self.pattern!r}, {self.flags!r})" |
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def try_compile(self) -> "Pattern[_T]": |
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"""Compile this :class:`Regex` as a Python regular expression. |
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.. warning:: |
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Python regular expressions use a different syntax and different |
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set of flags than MongoDB, which uses `PCRE`_. A regular |
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expression retrieved from the server may not compile in |
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Python, or may match a different set of strings in Python than |
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when used in a MongoDB query. :meth:`try_compile()` may raise |
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:exc:`re.error`. |
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.. _PCRE: http://www.pcre.org/ |
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""" |
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return re.compile(self.pattern, self.flags)
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