252 lines
6.3 KiB
Python
252 lines
6.3 KiB
Python
"""
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This module provides the :module:`hyperscan` backend for :class:`~pathspec.pathspec.PathSpec`.
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WARNING: The *pathspec._backends.hyperscan* package is not part of the public
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API. Its contents and structure are likely to change.
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"""
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from __future__ import annotations
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from collections.abc import (
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Sequence)
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from typing import (
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Any,
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Callable, # Replaced by `collections.abc.Callable` in 3.9.2.
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Optional) # Replaced by `X | None` in 3.10.
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try:
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import hyperscan
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except ModuleNotFoundError:
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hyperscan = None
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from pathspec.backend import (
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_Backend)
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from pathspec.pattern import (
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RegexPattern)
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from pathspec._typing import (
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override) # Added in 3.12.
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from .._utils import (
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enumerate_patterns)
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from .base import (
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hyperscan_error)
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from ._base import (
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HS_FLAGS,
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HyperscanExprDat,
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HyperscanExprDebug)
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class HyperscanPsBackend(_Backend):
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"""
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The :class:`HyperscanPsBackend` class is the :module:`hyperscan`
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implementation used by :class:`~pathspec.pathspec.PathSpec` for matching
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files. The Hyperscan database uses block mode for matching files.
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"""
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def __init__(
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self,
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patterns: Sequence[RegexPattern],
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*,
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_debug_exprs: Optional[bool] = None,
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_test_sort: Optional[Callable[[list], None]] = None,
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) -> None:
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"""
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Initialize the :class:`HyperscanPsBackend` instance.
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*patterns* (:class:`Sequence` of :class:`.RegexPattern`) contains the
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compiled patterns.
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"""
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if hyperscan is None:
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raise hyperscan_error
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if patterns and not isinstance(patterns[0], RegexPattern):
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raise TypeError(f"{patterns[0]=!r} must be a RegexPattern.")
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use_patterns = enumerate_patterns(
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patterns, filter=True, reverse=False,
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)
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debug_exprs = bool(_debug_exprs)
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if use_patterns:
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db = self._make_db()
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expr_data = self._init_db(
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db=db,
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debug=debug_exprs,
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patterns=use_patterns,
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sort_ids=_test_sort,
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)
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else:
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# WARNING: The hyperscan database cannot be initialized with zero
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# patterns.
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db = None
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expr_data = []
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self._db: Optional[hyperscan.Database] = db
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"""
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*_db* (:class:`hyperscan.Database`) is the Hyperscan database.
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"""
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self._debug_exprs = debug_exprs
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"""
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*_debug_exprs* (:class:`bool`) is whether to include additional debugging
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information for the expressions.
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"""
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self._expr_data: list[HyperscanExprDat] = expr_data
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"""
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*_expr_data* (:class:`list`) maps expression index (:class:`int`) to
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expression data (:class:`:class:`HyperscanExprDat`).
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"""
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self._out: tuple[Optional[bool], int] = (None, -1)
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"""
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*_out* (:class:`tuple`) stores the current match:
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- *0* (:class:`bool` or :data:`None`) is the match include.
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- *1* (:class:`int`) is the match index.
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"""
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self._patterns: dict[int, RegexPattern] = dict(use_patterns)
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"""
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*_patterns* (:class:`dict`) maps pattern index (:class:`int`) to pattern
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(:class:`RegexPattern`).
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"""
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@staticmethod
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def _init_db(
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db: hyperscan.Database,
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debug: bool,
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patterns: list[tuple[int, RegexPattern]],
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sort_ids: Optional[Callable[[list[int]], None]],
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) -> list[HyperscanExprDat]:
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"""
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Initialize the Hyperscan database from the given patterns.
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*db* (:class:`hyperscan.Hyperscan`) is the Hyperscan database.
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*debug* (:class:`bool`) is whether to include additional debugging
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information for the expressions.
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*patterns* (:class:`~collections.abc.Sequence` of :class:`.RegexPattern`)
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contains the patterns.
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*sort_ids* (:class:`callable` or :data:`None`) is a function used to sort
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the compiled expression ids. This is used during testing to ensure the order
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of expressions is not accidentally relied on.
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Returns a :class:`list` indexed by expression id (:class:`int`) to its data
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(:class:`HyperscanExprDat`).
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"""
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# WARNING: Hyperscan raises a `hyperscan.error` exception when compiled with
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# zero elements.
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assert patterns, patterns
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# Prepare patterns.
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expr_data: list[HyperscanExprDat] = []
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exprs: list[bytes] = []
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for pattern_index, pattern in patterns:
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assert pattern.include is not None, (pattern_index, pattern)
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# Encode regex.
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assert isinstance(pattern, RegexPattern), pattern
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regex = pattern.regex.pattern
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if isinstance(regex, bytes):
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regex_bytes = regex
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else:
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assert isinstance(regex, str), regex
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regex_bytes = regex.encode('utf8')
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if debug:
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expr_data.append(HyperscanExprDebug(
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include=pattern.include,
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index=pattern_index,
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is_dir_pattern=False,
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regex=regex,
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))
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else:
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expr_data.append(HyperscanExprDat(
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include=pattern.include,
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index=pattern_index,
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is_dir_pattern=False,
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))
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exprs.append(regex_bytes)
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# Sort expressions.
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ids = list(range(len(exprs)))
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if sort_ids is not None:
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sort_ids(ids)
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exprs = [exprs[__id] for __id in ids]
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# Compile patterns.
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db.compile(
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expressions=exprs,
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ids=ids,
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elements=len(exprs),
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flags=HS_FLAGS,
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)
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return expr_data
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@override
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def match_file(self, file: str) -> tuple[Optional[bool], Optional[int]]:
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"""
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Check the file against the patterns.
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*file* (:class:`str`) is the normalized file path to check.
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Returns a :class:`tuple` containing whether to include *file* (:class:`bool`
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or :data:`None`), and the index of the last matched pattern (:class:`int` or
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:data:`None`).
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"""
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# NOTICE: According to benchmarking, a method callback is 20% faster than
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# using a closure here.
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db = self._db
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if self._db is None:
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# Database was not initialized because there were no patterns. Return no
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# match.
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return (None, None)
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self._out = (None, -1)
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db.scan(file.encode('utf8'), match_event_handler=self.__on_match)
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out_include, out_index = self._out
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if out_index == -1:
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out_index = None
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return (out_include, out_index)
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@staticmethod
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def _make_db() -> hyperscan.Database:
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"""
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Create the Hyperscan database.
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Returns the database (:class:`hyperscan.Database`).
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"""
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return hyperscan.Database(mode=hyperscan.HS_MODE_BLOCK)
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def __on_match(
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self,
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expr_id: int,
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_from: int,
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_to: int,
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_flags: int,
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_context: Any,
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) -> Optional[bool]:
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"""
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Called on each match.
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*expr_id* (:class:`int`) is the expression id (index) of the matched
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pattern.
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"""
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# Store match.
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# - WARNING: Hyperscan does not guarantee matches will be produced in order!
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# Later expressions have higher priority.
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expr_dat = self._expr_data[expr_id]
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index = expr_dat.index
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prev_index = self._out[1]
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if index > prev_index:
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self._out = (expr_dat.include, index)
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