Mercurial > hg
view mercurial/rcutil.py @ 31956:c13ff31818b0
ui: add special-purpose atexit functionality
In spite of its longstanding use, Python's built-in atexit code is
not suitable for Mercurial's purposes, for several reasons:
* Handlers run after application code has finished.
* Because of this, the code that runs handlers swallows exceptions
(since there's no possible stacktrace to associate errors with).
If we're lucky, we'll get something spat out to stderr (if stderr
still works), which of course isn't any use in a big deployment
where it's important that exceptions get logged and aggregated.
* Mercurial's current atexit handlers make unfortunate assumptions
about process state (specifically stdio) that, coupled with the
above problems, make it impossible to deal with certain categories
of error (try "hg status > /dev/full" on a Linux box).
* In Python 3, the atexit implementation is completely hidden, so
we can't hijack the platform's atexit code to run handlers at a
time of our choosing.
As a result, here's a perfectly cromulent atexit-like implementation
over which we have control. This lets us decide exactly when the
handlers run (after each request has completed), and control what
the process state is when that occurs (and afterwards).
author | Bryan O'Sullivan <bryano@fb.com> |
---|---|
date | Tue, 11 Apr 2017 14:54:12 -0700 |
parents | e518192d6bac |
children | bf5e13e38390 |
line wrap: on
line source
# rcutil.py - utilities about config paths, special config sections etc. # # Copyright Mercurial Contributors # # 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 from . import ( encoding, osutil, pycompat, util, ) if pycompat.osname == 'nt': from . import scmwindows as scmplatform else: from . import scmposix as scmplatform systemrcpath = scmplatform.systemrcpath userrcpath = scmplatform.userrcpath def _expandrcpath(path): '''path could be a file or a directory. return a list of file paths''' p = util.expandpath(path) if os.path.isdir(p): join = os.path.join return [join(p, f) for f, k in osutil.listdir(p) if f.endswith('.rc')] return [p] def envrcitems(env=None): '''Return [(section, name, value, source)] config items. The config items are extracted from environment variables specified by env, used to override systemrc, but not userrc. If env is not provided, encoding.environ will be used. ''' if env is None: env = encoding.environ checklist = [ ('EDITOR', 'ui', 'editor'), ('VISUAL', 'ui', 'editor'), ('PAGER', 'pager', 'pager'), ] result = [] for envname, section, configname in checklist: if envname not in env: continue result.append((section, configname, env[envname], '$%s' % envname)) return result def defaultrcpath(): '''return rc paths in default.d''' path = [] defaultpath = os.path.join(util.datapath, 'default.d') if os.path.isdir(defaultpath): path = _expandrcpath(defaultpath) return path def rccomponents(): '''return an ordered [(type, obj)] about where to load configs. respect $HGRCPATH. if $HGRCPATH is empty, only .hg/hgrc of current repo is used. if $HGRCPATH is not set, the platform default will be used. if a directory is provided, *.rc files under it will be used. type could be either 'path' or 'items', if type is 'path', obj is a string, and is the config file path. if type is 'items', obj is a list of (section, name, value, source) that should fill the config directly. ''' envrc = ('items', envrcitems()) if 'HGRCPATH' in encoding.environ: # assume HGRCPATH is all about user configs so environments can be # overridden. _rccomponents = [envrc] for p in encoding.environ['HGRCPATH'].split(pycompat.ospathsep): if not p: continue _rccomponents.extend(('path', p) for p in _expandrcpath(p)) else: normpaths = lambda paths: [('path', os.path.normpath(p)) for p in paths] _rccomponents = normpaths(defaultrcpath() + systemrcpath()) _rccomponents.append(envrc) _rccomponents.extend(normpaths(userrcpath())) return _rccomponents def defaultpagerenv(): '''return a dict of default environment variables and their values, intended to be set before starting a pager. ''' return {'LESS': 'FRX', 'LV': '-c'}