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
# hook.py - hook support for mercurial
#
# Copyright 2007 Matt Mackall <mpm@selenic.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
import time
from .i18n import _
from . import (
demandimport,
error,
extensions,
util,
)
def _pythonhook(ui, repo, name, hname, funcname, args, throw):
'''call python hook. hook is callable object, looked up as
name in python module. if callable returns "true", hook
fails, else passes. if hook raises exception, treated as
hook failure. exception propagates if throw is "true".
reason for "true" meaning "hook failed" is so that
unmodified commands (e.g. mercurial.commands.update) can
be run as hooks without wrappers to convert return values.'''
if callable(funcname):
obj = funcname
funcname = obj.__module__ + "." + obj.__name__
else:
d = funcname.rfind('.')
if d == -1:
raise error.HookLoadError(
_('%s hook is invalid: "%s" not in a module')
% (hname, funcname))
modname = funcname[:d]
oldpaths = sys.path
if util.mainfrozen():
# binary installs require sys.path manipulation
modpath, modfile = os.path.split(modname)
if modpath and modfile:
sys.path = sys.path[:] + [modpath]
modname = modfile
with demandimport.deactivated():
try:
obj = __import__(modname)
except (ImportError, SyntaxError):
e1 = sys.exc_info()
try:
# extensions are loaded with hgext_ prefix
obj = __import__("hgext_%s" % modname)
except (ImportError, SyntaxError):
e2 = sys.exc_info()
if ui.tracebackflag:
ui.warn(_('exception from first failed import '
'attempt:\n'))
ui.traceback(e1)
if ui.tracebackflag:
ui.warn(_('exception from second failed import '
'attempt:\n'))
ui.traceback(e2)
if not ui.tracebackflag:
tracebackhint = _(
'run with --traceback for stack trace')
else:
tracebackhint = None
raise error.HookLoadError(
_('%s hook is invalid: import of "%s" failed') %
(hname, modname), hint=tracebackhint)
sys.path = oldpaths
try:
for p in funcname.split('.')[1:]:
obj = getattr(obj, p)
except AttributeError:
raise error.HookLoadError(
_('%s hook is invalid: "%s" is not defined')
% (hname, funcname))
if not callable(obj):
raise error.HookLoadError(
_('%s hook is invalid: "%s" is not callable')
% (hname, funcname))
ui.note(_("calling hook %s: %s\n") % (hname, funcname))
starttime = time.time()
try:
r = obj(ui=ui, repo=repo, hooktype=name, **args)
except Exception as exc:
if isinstance(exc, error.Abort):
ui.warn(_('error: %s hook failed: %s\n') %
(hname, exc.args[0]))
else:
ui.warn(_('error: %s hook raised an exception: '
'%s\n') % (hname, exc))
if throw:
raise
if not ui.tracebackflag:
ui.warn(_('(run with --traceback for stack trace)\n'))
ui.traceback()
return True, True
finally:
duration = time.time() - starttime
ui.log('pythonhook', 'pythonhook-%s: %s finished in %0.2f seconds\n',
name, funcname, duration)
if r:
if throw:
raise error.HookAbort(_('%s hook failed') % hname)
ui.warn(_('warning: %s hook failed\n') % hname)
return r, False
def _exthook(ui, repo, name, cmd, args, throw):
ui.note(_("running hook %s: %s\n") % (name, cmd))
starttime = time.time()
env = {}
# make in-memory changes visible to external process
if repo is not None:
tr = repo.currenttransaction()
repo.dirstate.write(tr)
if tr and tr.writepending():
env['HG_PENDING'] = repo.root
for k, v in args.iteritems():
if callable(v):
v = v()
if isinstance(v, dict):
# make the dictionary element order stable across Python
# implementations
v = ('{' +
', '.join('%r: %r' % i for i in sorted(v.iteritems())) +
'}')
env['HG_' + k.upper()] = v
if repo:
cwd = repo.root
else:
cwd = os.getcwd()
r = ui.system(cmd, environ=env, cwd=cwd)
duration = time.time() - starttime
ui.log('exthook', 'exthook-%s: %s finished in %0.2f seconds\n',
name, cmd, duration)
if r:
desc, r = util.explainexit(r)
if throw:
raise error.HookAbort(_('%s hook %s') % (name, desc))
ui.warn(_('warning: %s hook %s\n') % (name, desc))
return r
# represent an untrusted hook command
_fromuntrusted = object()
def _allhooks(ui):
"""return a list of (hook-id, cmd) pairs sorted by priority"""
hooks = _hookitems(ui)
# Be careful in this section, propagating the real commands from untrusted
# sources would create a security vulnerability, make sure anything altered
# in that section uses "_fromuntrusted" as its command.
untrustedhooks = _hookitems(ui, _untrusted=True)
for name, value in untrustedhooks.items():
trustedvalue = hooks.get(name, (None, None, name, _fromuntrusted))
if value != trustedvalue:
(lp, lo, lk, lv) = trustedvalue
hooks[name] = (lp, lo, lk, _fromuntrusted)
# (end of the security sensitive section)
return [(k, v) for p, o, k, v in sorted(hooks.values())]
def _hookitems(ui, _untrusted=False):
"""return all hooks items ready to be sorted"""
hooks = {}
for name, cmd in ui.configitems('hooks', untrusted=_untrusted):
if not name.startswith('priority'):
priority = ui.configint('hooks', 'priority.%s' % name, 0)
hooks[name] = (-priority, len(hooks), name, cmd)
return hooks
_redirect = False
def redirect(state):
global _redirect
_redirect = state
def hook(ui, repo, name, throw=False, **args):
if not ui.callhooks:
return False
hooks = []
for hname, cmd in _allhooks(ui):
if hname.split('.')[0] == name and cmd:
hooks.append((hname, cmd))
res = runhooks(ui, repo, name, hooks, throw=throw, **args)
r = False
for hname, cmd in hooks:
r = res[hname][0] or r
return r
def runhooks(ui, repo, name, hooks, throw=False, **args):
res = {}
oldstdout = -1
try:
for hname, cmd in hooks:
if oldstdout == -1 and _redirect:
try:
stdoutno = sys.stdout.fileno()
stderrno = sys.stderr.fileno()
# temporarily redirect stdout to stderr, if possible
if stdoutno >= 0 and stderrno >= 0:
sys.stdout.flush()
oldstdout = os.dup(stdoutno)
os.dup2(stderrno, stdoutno)
except (OSError, AttributeError):
# files seem to be bogus, give up on redirecting (WSGI, etc)
pass
if cmd is _fromuntrusted:
if throw:
raise error.HookAbort(
_('untrusted hook %s not executed') % name,
hint = _("see 'hg help config.trusted'"))
ui.warn(_('warning: untrusted hook %s not executed\n') % name)
r = 1
raised = False
elif callable(cmd):
r, raised = _pythonhook(ui, repo, name, hname, cmd, args, throw)
elif cmd.startswith('python:'):
if cmd.count(':') >= 2:
path, cmd = cmd[7:].rsplit(':', 1)
path = util.expandpath(path)
if repo:
path = os.path.join(repo.root, path)
try:
mod = extensions.loadpath(path, 'hghook.%s' % hname)
except Exception:
ui.write(_("loading %s hook failed:\n") % hname)
raise
hookfn = getattr(mod, cmd)
else:
hookfn = cmd[7:].strip()
r, raised = _pythonhook(ui, repo, name, hname, hookfn, args,
throw)
else:
r = _exthook(ui, repo, hname, cmd, args, throw)
raised = False
res[hname] = r, raised
# The stderr is fully buffered on Windows when connected to a pipe.
# A forcible flush is required to make small stderr data in the
# remote side available to the client immediately.
sys.stderr.flush()
finally:
if _redirect and oldstdout >= 0:
sys.stdout.flush() # write hook output to stderr fd
os.dup2(oldstdout, stdoutno)
os.close(oldstdout)
return res