view hgdemandimport/__init__.py @ 39816:ae20f52437e9

wireprotov2: advertise recognized path filter prefixes

While the wire protocol doesn't yet support it, we'll eventually
have commands that accept narrow patterns to specify the set of
files relevant to a command.

For security and performance reasons, only specific filter types
are allowed.

This commit teaches the server to advertise the set of allowed
filter types. By doing so, clients can e.g. validate user-specified
patterns against the server's abilities without having to send
a command to retrieve data.

Having the data in the capabilities data structure will also serve
as a check against unwanted BC.

Differential Revision: https://phab.mercurial-scm.org/D4616

# 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()