Mercurial > hg
view mercurial/policy.py @ 38526:313a940d49a3
ui: add an uninterruptable context manager that can block SIGINT
The blocking of SIGINT is not done by default, but my hope is that we
will one day. This was inspired by Facebook's "nointerrupt" extension,
which is a bit more heavy-handed than this (whole commands are treated
as unsafe to interrupt). A future patch will enable this for varying
bits of Mercurial that are performing unsafe operations.
It's intentional that the KeyboardInterrupt is raised as the context
manager exits: during the span of the context manager interrupting
Mercurial could lead to data loss, but typically those spans are
fairly narrow, so we can let the unsafe block complete and then
terminate hg (which will leave the repo in a consistent state, even if
it's not the user's desired state).
.. api::
New context manager ``ui.uninterruptable()`` to mark portions of a command
as potentially unsafe places to interrupt Mercurial with Control-C or
similar.
Differential Revision: https://phab.mercurial-scm.org/D3716
author | Augie Fackler <augie@google.com> |
---|---|
date | Wed, 27 Jun 2018 10:47:14 -0400 |
parents | 0304f22497fa |
children | 6104b203bec8 adacefb0b7ea |
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# policy.py - module policy logic for Mercurial. # # Copyright 2015 Gregory Szorc <gregory.szorc@gmail.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import os import sys # Rules for how modules can be loaded. Values are: # # c - require C extensions # allow - allow pure Python implementation when C loading fails # cffi - required cffi versions (implemented within pure module) # cffi-allow - allow pure Python implementation if cffi version is missing # py - only load pure Python modules # # By default, fall back to the pure modules so the in-place build can # run without recompiling the C extensions. This will be overridden by # __modulepolicy__ generated by setup.py. policy = b'allow' _packageprefs = { # policy: (versioned package, pure package) b'c': (r'cext', None), b'allow': (r'cext', r'pure'), b'cffi': (r'cffi', None), b'cffi-allow': (r'cffi', r'pure'), b'py': (None, r'pure'), } try: from . import __modulepolicy__ policy = __modulepolicy__.modulepolicy except ImportError: pass # PyPy doesn't load C extensions. # # The canonical way to do this is to test platform.python_implementation(). # But we don't import platform and don't bloat for it here. if r'__pypy__' in sys.builtin_module_names: policy = b'cffi' # Environment variable can always force settings. if sys.version_info[0] >= 3: if r'HGMODULEPOLICY' in os.environ: policy = os.environ[r'HGMODULEPOLICY'].encode(r'utf-8') else: policy = os.environ.get(r'HGMODULEPOLICY', policy) def _importfrom(pkgname, modname): # from .<pkgname> import <modname> (where . is looked through this module) fakelocals = {} pkg = __import__(pkgname, globals(), fakelocals, [modname], level=1) try: fakelocals[modname] = mod = getattr(pkg, modname) except AttributeError: raise ImportError(r'cannot import name %s' % modname) # force import; fakelocals[modname] may be replaced with the real module getattr(mod, r'__doc__', None) return fakelocals[modname] # keep in sync with "version" in C modules _cextversions = { (r'cext', r'base85'): 1, (r'cext', r'bdiff'): 3, (r'cext', r'mpatch'): 1, (r'cext', r'osutil'): 4, (r'cext', r'parsers'): 5, } # map import request to other package or module _modredirects = { (r'cext', r'charencode'): (r'cext', r'parsers'), (r'cffi', r'base85'): (r'pure', r'base85'), (r'cffi', r'charencode'): (r'pure', r'charencode'), (r'cffi', r'parsers'): (r'pure', r'parsers'), } def _checkmod(pkgname, modname, mod): expected = _cextversions.get((pkgname, modname)) actual = getattr(mod, r'version', None) if actual != expected: raise ImportError(r'cannot import module %s.%s ' r'(expected version: %d, actual: %r)' % (pkgname, modname, expected, actual)) def importmod(modname): """Import module according to policy and check API version""" try: verpkg, purepkg = _packageprefs[policy] except KeyError: raise ImportError(r'invalid HGMODULEPOLICY %r' % policy) assert verpkg or purepkg if verpkg: pn, mn = _modredirects.get((verpkg, modname), (verpkg, modname)) try: mod = _importfrom(pn, mn) if pn == verpkg: _checkmod(pn, mn, mod) return mod except ImportError: if not purepkg: raise pn, mn = _modredirects.get((purepkg, modname), (purepkg, modname)) return _importfrom(pn, mn)