match: avoid translating glob to matcher multiple times for large sets
For hgignore with many globs, the resulting regexp might not fit under the 20K
length limit. So the patterns need to be broken up in smaller pieces.
Before this change, the logic was re-starting the full process from scratch
for each smaller pieces, including the translation of globs into regexp.
Effectively doing the work over and over.
If the 20K limit is reached, we are likely in a case where there is many such
glob, so exporting them is especially expensive and we should be careful not
to do that work more than once.
To work around this, we now translate glob to regexp once and for all. Then,
we assemble the resulting individual regexp into valid blocks.
This raises a very significant performance win for large `.hgignore file`:
Before: ! wall 0.153153 comb 0.150000 user 0.150000 sys 0.000000 (median of 66)
After: ! wall 0.059793 comb 0.060000 user 0.060000 sys 0.000000 (median of 100)
# hgdemandimport - global demand-loading of modules for Mercurial
#
# Copyright 2017 Facebook Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''demandimport - automatic demand-loading of modules'''
# This is in a separate package from mercurial because in Python 3,
# demand loading is per-package. Keeping demandimport in the mercurial package
# would disable demand loading for any modules in mercurial.
from __future__ import absolute_import
import os
import sys
if sys.version_info[0] >= 3:
from . import demandimportpy3 as demandimport
else:
from . import demandimportpy2 as demandimport
# Full module names which can't be lazy imported.
# Extensions can add to this set.
IGNORES = {
'__future__',
'_hashlib',
# ImportError during pkg_resources/__init__.py:fixup_namespace_package
'_imp',
'_xmlplus',
'fcntl',
'nt', # pathlib2 tests the existence of built-in 'nt' module
'win32com.gen_py',
'win32com.shell', # 'appdirs' tries to import win32com.shell
'_winreg', # 2.7 mimetypes needs immediate ImportError
'pythoncom',
# imported by tarfile, not available under Windows
'pwd',
'grp',
# imported by profile, itself imported by hotshot.stats,
# not available under Windows
'resource',
# this trips up many extension authors
'gtk',
# setuptools' pkg_resources.py expects "from __main__ import x" to
# raise ImportError if x not defined
'__main__',
'_ssl', # conditional imports in the stdlib, issue1964
'_sre', # issue4920
'rfc822',
'mimetools',
'sqlalchemy.events', # has import-time side effects (issue5085)
# setuptools 8 expects this module to explode early when not on windows
'distutils.msvc9compiler',
'__builtin__',
'builtins',
'urwid.command_map', # for pudb
}
_pypy = '__pypy__' in sys.builtin_module_names
if _pypy:
# _ctypes.pointer is shadowed by "from ... import pointer" (PyPy 5)
IGNORES.add('_ctypes.pointer')
demandimport.init(IGNORES)
# Re-export.
isenabled = demandimport.isenabled
disable = demandimport.disable
deactivated = demandimport.deactivated
def enable():
# chg pre-imports modules so do not enable demandimport for it
if ('CHGINTERNALMARK' not in os.environ
and os.environ.get('HGDEMANDIMPORT') != 'disable'):
demandimport.enable()