demandimport: delay loading for "from a import b" with absolute_import
Before this patch, "from a import b" doesn't delay loading module "b",
if absolute_import is enabled, even though "from . import b" does.
For example:
- it is assumed that extension X has "from P import M" for module M
under package P with absolute_import feature
- if importing module M is already delayed before loading extension
X, loading module M in extension X is delayed until actually
referring
util, cmdutil, scmutil or so of Mercurial itself should be
imported by "from . import M" style before loading extension X
- otherwise, module M is loaded immediately at loading extension X,
even if extension X itself isn't used at that "hg" command invocation
Some minor modules (e.g. filemerge or so) of Mercurial itself
aren't imported by "from . import M" style before loading
extension X. And of course, external libraries aren't, too.
This might cause startup performance problem of hg command, because
many bundled extensions already enable absolute_import feature.
To delay loading module for "from a import b" with absolute_import
feature, this patch does below in "from a (or .a) import b" with
absolute_import case:
1. import root module of "name" by system built-in __import__
(referred as _origimport)
2. recurse down the module chain for hierarchical "name"
This logic can be shared with non absolute_import
case. Therefore, this patch also centralizes it into chainmodules().
3. and fall through to process elements in "fromlist" for the leaf
module of "name"
Processing elements in "fromlist" is executed in the code path
after "if _pypy: .... else: ..." clause. Therefore, this patch
replaces "if _pypy:" with "elif _pypy:" to share it.
At 4f1144c3c72b introducing original "work around" for "from a import
b" case, elements in "fromlist" were imported with "level=level". But
"level" might be grater than 1 (e.g. level=2 in "from .. import b"
case) at demandimport() invocation, and importing direct sub-module in
"fromlist" with level grater than 1 causes unexpected result.
IMHO, this seems main reason of "errors for unknown reason" described
in 4f1144c3c72b, and we don't have to worry about it, because this
issue was already fixed by 78d05778907b.
This is reason why this patch removes "errors for unknown reasons"
comment.
# sshpeer.py - ssh repository proxy class for mercurial
#
# Copyright 2005, 2006 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 re
from .i18n import _
from . import (
error,
util,
wireproto,
)
class remotelock(object):
def __init__(self, repo):
self.repo = repo
def release(self):
self.repo.unlock()
self.repo = None
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
if self.repo:
self.release()
def __del__(self):
if self.repo:
self.release()
def _serverquote(s):
if not s:
return s
'''quote a string for the remote shell ... which we assume is sh'''
if re.match('[a-zA-Z0-9@%_+=:,./-]*$', s):
return s
return "'%s'" % s.replace("'", "'\\''")
def _forwardoutput(ui, pipe):
"""display all data currently available on pipe as remote output.
This is non blocking."""
s = util.readpipe(pipe)
if s:
for l in s.splitlines():
ui.status(_("remote: "), l, '\n')
class doublepipe(object):
"""Operate a side-channel pipe in addition of a main one
The side-channel pipe contains server output to be forwarded to the user
input. The double pipe will behave as the "main" pipe, but will ensure the
content of the "side" pipe is properly processed while we wait for blocking
call on the "main" pipe.
If large amounts of data are read from "main", the forward will cease after
the first bytes start to appear. This simplifies the implementation
without affecting actual output of sshpeer too much as we rarely issue
large read for data not yet emitted by the server.
The main pipe is expected to be a 'bufferedinputpipe' from the util module
that handle all the os specific bites. This class lives in this module
because it focus on behavior specific to the ssh protocol."""
def __init__(self, ui, main, side):
self._ui = ui
self._main = main
self._side = side
def _wait(self):
"""wait until some data are available on main or side
return a pair of boolean (ismainready, issideready)
(This will only wait for data if the setup is supported by `util.poll`)
"""
if getattr(self._main, 'hasbuffer', False): # getattr for classic pipe
return (True, True) # main has data, assume side is worth poking at.
fds = [self._main.fileno(), self._side.fileno()]
try:
act = util.poll(fds)
except NotImplementedError:
# non supported yet case, assume all have data.
act = fds
return (self._main.fileno() in act, self._side.fileno() in act)
def write(self, data):
return self._call('write', data)
def read(self, size):
return self._call('read', size)
def readline(self):
return self._call('readline')
def _call(self, methname, data=None):
"""call <methname> on "main", forward output of "side" while blocking
"""
# data can be '' or 0
if (data is not None and not data) or self._main.closed:
_forwardoutput(self._ui, self._side)
return ''
while True:
mainready, sideready = self._wait()
if sideready:
_forwardoutput(self._ui, self._side)
if mainready:
meth = getattr(self._main, methname)
if data is None:
return meth()
else:
return meth(data)
def close(self):
return self._main.close()
def flush(self):
return self._main.flush()
class sshpeer(wireproto.wirepeer):
def __init__(self, ui, path, create=False):
self._url = path
self.ui = ui
self.pipeo = self.pipei = self.pipee = None
u = util.url(path, parsequery=False, parsefragment=False)
if u.scheme != 'ssh' or not u.host or u.path is None:
self._abort(error.RepoError(_("couldn't parse location %s") % path))
self.user = u.user
if u.passwd is not None:
self._abort(error.RepoError(_("password in URL not supported")))
self.host = u.host
self.port = u.port
self.path = u.path or "."
sshcmd = self.ui.config("ui", "ssh", "ssh")
remotecmd = self.ui.config("ui", "remotecmd", "hg")
args = util.sshargs(sshcmd,
_serverquote(self.host),
_serverquote(self.user),
_serverquote(self.port))
if create:
cmd = '%s %s %s' % (sshcmd, args,
util.shellquote("%s init %s" %
(_serverquote(remotecmd), _serverquote(self.path))))
ui.debug('running %s\n' % cmd)
res = ui.system(cmd)
if res != 0:
self._abort(error.RepoError(_("could not create remote repo")))
self._validaterepo(sshcmd, args, remotecmd)
def url(self):
return self._url
def _validaterepo(self, sshcmd, args, remotecmd):
# cleanup up previous run
self.cleanup()
cmd = '%s %s %s' % (sshcmd, args,
util.shellquote("%s -R %s serve --stdio" %
(_serverquote(remotecmd), _serverquote(self.path))))
self.ui.debug('running %s\n' % cmd)
cmd = util.quotecommand(cmd)
# while self.subprocess isn't used, having it allows the subprocess to
# to clean up correctly later
#
# no buffer allow the use of 'select'
# feel free to remove buffering and select usage when we ultimately
# move to threading.
sub = util.popen4(cmd, bufsize=0)
self.pipeo, self.pipei, self.pipee, self.subprocess = sub
self.pipei = util.bufferedinputpipe(self.pipei)
self.pipei = doublepipe(self.ui, self.pipei, self.pipee)
self.pipeo = doublepipe(self.ui, self.pipeo, self.pipee)
# skip any noise generated by remote shell
self._callstream("hello")
r = self._callstream("between", pairs=("%s-%s" % ("0"*40, "0"*40)))
lines = ["", "dummy"]
max_noise = 500
while lines[-1] and max_noise:
l = r.readline()
self.readerr()
if lines[-1] == "1\n" and l == "\n":
break
if l:
self.ui.debug("remote: ", l)
lines.append(l)
max_noise -= 1
else:
self._abort(error.RepoError(_('no suitable response from '
'remote hg')))
self._caps = set()
for l in reversed(lines):
if l.startswith("capabilities:"):
self._caps.update(l[:-1].split(":")[1].split())
break
def _capabilities(self):
return self._caps
def readerr(self):
_forwardoutput(self.ui, self.pipee)
def _abort(self, exception):
self.cleanup()
raise exception
def cleanup(self):
if self.pipeo is None:
return
self.pipeo.close()
self.pipei.close()
try:
# read the error descriptor until EOF
for l in self.pipee:
self.ui.status(_("remote: "), l)
except (IOError, ValueError):
pass
self.pipee.close()
__del__ = cleanup
def _submitbatch(self, req):
cmds = []
for op, argsdict in req:
args = ','.join('%s=%s' % (wireproto.escapearg(k),
wireproto.escapearg(v))
for k, v in argsdict.iteritems())
cmds.append('%s %s' % (op, args))
rsp = self._callstream("batch", cmds=';'.join(cmds))
available = self._getamount()
# TODO this response parsing is probably suboptimal for large
# batches with large responses.
toread = min(available, 1024)
work = rsp.read(toread)
available -= toread
chunk = work
while chunk:
while ';' in work:
one, work = work.split(';', 1)
yield wireproto.unescapearg(one)
toread = min(available, 1024)
chunk = rsp.read(toread)
available -= toread
work += chunk
yield wireproto.unescapearg(work)
def _callstream(self, cmd, **args):
self.ui.debug("sending %s command\n" % cmd)
self.pipeo.write("%s\n" % cmd)
_func, names = wireproto.commands[cmd]
keys = names.split()
wireargs = {}
for k in keys:
if k == '*':
wireargs['*'] = args
break
else:
wireargs[k] = args[k]
del args[k]
for k, v in sorted(wireargs.iteritems()):
self.pipeo.write("%s %d\n" % (k, len(v)))
if isinstance(v, dict):
for dk, dv in v.iteritems():
self.pipeo.write("%s %d\n" % (dk, len(dv)))
self.pipeo.write(dv)
else:
self.pipeo.write(v)
self.pipeo.flush()
return self.pipei
def _callcompressable(self, cmd, **args):
return self._callstream(cmd, **args)
def _call(self, cmd, **args):
self._callstream(cmd, **args)
return self._recv()
def _callpush(self, cmd, fp, **args):
r = self._call(cmd, **args)
if r:
return '', r
while True:
d = fp.read(4096)
if not d:
break
self._send(d)
self._send("", flush=True)
r = self._recv()
if r:
return '', r
return self._recv(), ''
def _calltwowaystream(self, cmd, fp, **args):
r = self._call(cmd, **args)
if r:
# XXX needs to be made better
raise error.Abort('unexpected remote reply: %s' % r)
while True:
d = fp.read(4096)
if not d:
break
self._send(d)
self._send("", flush=True)
return self.pipei
def _getamount(self):
l = self.pipei.readline()
if l == '\n':
self.readerr()
msg = _('check previous remote output')
self._abort(error.OutOfBandError(hint=msg))
self.readerr()
try:
return int(l)
except ValueError:
self._abort(error.ResponseError(_("unexpected response:"), l))
def _recv(self):
return self.pipei.read(self._getamount())
def _send(self, data, flush=False):
self.pipeo.write("%d\n" % len(data))
if data:
self.pipeo.write(data)
if flush:
self.pipeo.flush()
self.readerr()
def lock(self):
self._call("lock")
return remotelock(self)
def unlock(self):
self._call("unlock")
def addchangegroup(self, cg, source, url, lock=None):
'''Send a changegroup to the remote server. Return an integer
similar to unbundle(). DEPRECATED, since it requires locking the
remote.'''
d = self._call("addchangegroup")
if d:
self._abort(error.RepoError(_("push refused: %s") % d))
while True:
d = cg.read(4096)
if not d:
break
self.pipeo.write(d)
self.readerr()
self.pipeo.flush()
self.readerr()
r = self._recv()
if not r:
return 1
try:
return int(r)
except ValueError:
self._abort(error.ResponseError(_("unexpected response:"), r))
instance = sshpeer