setup: add flag to build_ext to control building zstd
Downstream packagers will inevitably want to disable building the
vendored python-zstandard Python package. Rather than force them
to patch setup.py, let's give them a knob to use.
distutils Command classes support defining custom options. It requires
setting certain class attributes (yes, class attributes: instance
attributes don't work because the class type is consulted before it
is instantiated).
We already have a custom child class of build_ext, so we set these
class attributes, implement some scaffolding, and override
build_extensions to filter the Extension instance for the zstd
extension if the `--no-zstd` argument is specified.
Example usage:
$ python setup.py build_ext --no-zstd
# Copyright (C) 2006 - Marco Barisione <marco@barisione.org>
#
# This is a small extension for Mercurial (https://mercurial-scm.org/)
# that removes files not known to mercurial
#
# This program was inspired by the "cvspurge" script contained in CVS
# utilities (http://www.red-bean.com/cvsutils/).
#
# For help on the usage of "hg purge" use:
# hg help purge
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.
'''command to delete untracked files from the working directory'''
from __future__ import absolute_import
import os
from mercurial.i18n import _
from mercurial import (
cmdutil,
commands,
error,
scmutil,
util,
)
cmdtable = {}
command = cmdutil.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'
@command('purge|clean',
[('a', 'abort-on-err', None, _('abort if an error occurs')),
('', 'all', None, _('purge ignored files too')),
('', 'dirs', None, _('purge empty directories')),
('', 'files', None, _('purge files')),
('p', 'print', None, _('print filenames instead of deleting them')),
('0', 'print0', None, _('end filenames with NUL, for use with xargs'
' (implies -p/--print)')),
] + commands.walkopts,
_('hg purge [OPTION]... [DIR]...'))
def purge(ui, repo, *dirs, **opts):
'''removes files not tracked by Mercurial
Delete files not known to Mercurial. This is useful to test local
and uncommitted changes in an otherwise-clean source tree.
This means that purge will delete the following by default:
- Unknown files: files marked with "?" by :hg:`status`
- Empty directories: in fact Mercurial ignores directories unless
they contain files under source control management
But it will leave untouched:
- Modified and unmodified tracked files
- Ignored files (unless --all is specified)
- New files added to the repository (with :hg:`add`)
The --files and --dirs options can be used to direct purge to delete
only files, only directories, or both. If neither option is given,
both will be deleted.
If directories are given on the command line, only files in these
directories are considered.
Be careful with purge, as you could irreversibly delete some files
you forgot to add to the repository. If you only want to print the
list of files that this program would delete, use the --print
option.
'''
act = not opts.get('print')
eol = '\n'
if opts.get('print0'):
eol = '\0'
act = False # --print0 implies --print
removefiles = opts.get('files')
removedirs = opts.get('dirs')
if not removefiles and not removedirs:
removefiles = True
removedirs = True
def remove(remove_func, name):
if act:
try:
remove_func(repo.wjoin(name))
except OSError:
m = _('%s cannot be removed') % name
if opts.get('abort_on_err'):
raise error.Abort(m)
ui.warn(_('warning: %s\n') % m)
else:
ui.write('%s%s' % (name, eol))
match = scmutil.match(repo[None], dirs, opts)
if removedirs:
directories = []
match.explicitdir = match.traversedir = directories.append
status = repo.status(match=match, ignored=opts.get('all'), unknown=True)
if removefiles:
for f in sorted(status.unknown + status.ignored):
if act:
ui.note(_('removing file %s\n') % f)
remove(util.unlink, f)
if removedirs:
for f in sorted(directories, reverse=True):
if match(f) and not os.listdir(repo.wjoin(f)):
if act:
ui.note(_('removing directory %s\n') % f)
remove(os.rmdir, f)