# chgserver.py - command server extension for cHg

#

# Copyright 2011 Yuya Nishihara <yuya@tcha.org>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

"""command server extension for cHg (EXPERIMENTAL)

'S' channel (read/write)

    propagate ui.system() request to client

'attachio' command

    attach client's stdio passed by sendmsg()

'chdir' command

    change current directory

'getpager' command

    checks if pager is enabled and which pager should be executed

'setenv' command

    replace os.environ completely

'SIGHUP' signal

    reload configuration files

"""

from __future__ import absolute_import

import SocketServer

import errno

import os

import re

import signal

import struct

import threading

import time

import traceback

from mercurial.i18n import _

from mercurial import (

    cmdutil,

    commands,

    commandserver,

    dispatch,

    error,

    osutil,

    util,

)

# Note for extension authors: ONLY specify testedwith = 'internal' 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 = 'internal'

_log = commandserver.log

def _hashlist(items):

    """return sha1 hexdigest for a list"""

    return util.sha1(str(items)).hexdigest()

# sensitive config sections affecting confighash

_configsections = ['extensions']

# sensitive environment variables affecting confighash

_envre = re.compile(r'''\A(?:

                    CHGHG

                    |HG.*

                    |LANG(?:UAGE)?

                    |LC_.*

                    |LD_.*

                    |PATH

                    |PYTHON.*

                    |TERM(?:INFO)?

                    |TZ

                    )\Z''', re.X)

def _confighash(ui):

    """return a quick hash for detecting config/env changes

    confighash is the hash of sensitive config items and environment variables.

    for chgserver, it is designed that once confighash changes, the server is

    not qualified to serve its client and should redirect the client to a new

    server. different from mtimehash, confighash change will not mark the

    server outdated and exit since the user can have different configs at the

    same time.

    """

    sectionitems = []

    for section in _configsections:

        sectionitems.append(ui.configitems(section))

    sectionhash = _hashlist(sectionitems)

    envitems = [(k, v) for k, v in os.environ.iteritems() if _envre.match(k)]

    envhash = _hashlist(sorted(envitems))

    return sectionhash[:6] + envhash[:6]

# copied from hgext/pager.py:uisetup()

def _setuppagercmd(ui, options, cmd):

    if not ui.formatted():

        return

    p = ui.config("pager", "pager", os.environ.get("PAGER"))

    usepager = False

    always = util.parsebool(options['pager'])

    auto = options['pager'] == 'auto'

    if not p:

        pass

    elif always:

        usepager = True

    elif not auto:

        usepager = False

    else:

        attended = ['annotate', 'cat', 'diff', 'export', 'glog', 'log', 'qdiff']

        attend = ui.configlist('pager', 'attend', attended)

        ignore = ui.configlist('pager', 'ignore')

        cmds, _ = cmdutil.findcmd(cmd, commands.table)

        for cmd in cmds:

            var = 'attend-%s' % cmd

            if ui.config('pager', var):

                usepager = ui.configbool('pager', var)

                break

            if (cmd in attend or

                (cmd not in ignore and not attend)):

                usepager = True

                break

    if usepager:

        ui.setconfig('ui', 'formatted', ui.formatted(), 'pager')

        ui.setconfig('ui', 'interactive', False, 'pager')

        return p

_envvarre = re.compile(r'\$[a-zA-Z_]+')

def _clearenvaliases(cmdtable):

    """Remove stale command aliases referencing env vars; variable expansion

    is done at dispatch.addaliases()"""

    for name, tab in cmdtable.items():

        cmddef = tab[0]

        if (isinstance(cmddef, dispatch.cmdalias) and

            not cmddef.definition.startswith('!') and  # shell alias

            _envvarre.search(cmddef.definition)):

            del cmdtable[name]

def _newchgui(srcui, csystem):

    class chgui(srcui.__class__):

        def __init__(self, src=None):

            super(chgui, self).__init__(src)

            if src:

                self._csystem = getattr(src, '_csystem', csystem)

            else:

                self._csystem = csystem

        def system(self, cmd, environ=None, cwd=None, onerr=None,

                   errprefix=None):

            # copied from mercurial/util.py:system()

            self.flush()

            def py2shell(val):

                if val is None or val is False:

                    return '0'

                if val is True:

                    return '1'

                return str(val)

            env = os.environ.copy()

            if environ:

                env.update((k, py2shell(v)) for k, v in environ.iteritems())

            env['HG'] = util.hgexecutable()

            rc = self._csystem(cmd, env, cwd)

            if rc and onerr:

                errmsg = '%s %s' % (os.path.basename(cmd.split(None, 1)[0]),

                                    util.explainexit(rc)[0])

                if errprefix:

                    errmsg = '%s: %s' % (errprefix, errmsg)

                raise onerr(errmsg)

            return rc

    return chgui(srcui)

    newui = srcui.__class__()

    for a in ['fin', 'fout', 'ferr', 'environ']:

        setattr(newui, a, getattr(srcui, a))

    if util.safehasattr(srcui, '_csystem'):

        newui._csystem = srcui._csystem

    # stolen from tortoisehg.util.copydynamicconfig()

    for section, name, value in srcui.walkconfig():

        source = srcui.configsource(section, name)

            continue

        if source == 'none':

            # ui.configsource returns 'none' by default

            source = ''

        newui.setconfig(section, name, value, source)

    return newui

class channeledsystem(object):

    """Propagate ui.system() request in the following format:

    payload length (unsigned int),

    cmd, '\0',

    cwd, '\0',

    envkey, '=', val, '\0',

    ...

    envkey, '=', val

    and waits:

    exitcode length (unsigned int),

    exitcode (int)

    """

    def __init__(self, in_, out, channel):

        self.in_ = in_

        self.out = out

        self.channel = channel

    def __call__(self, cmd, environ, cwd):

        args = [util.quotecommand(cmd), cwd or '.']

        args.extend('%s=%s' % (k, v) for k, v in environ.iteritems())

        data = '\0'.join(args)

        self.out.write(struct.pack('>cI', self.channel, len(data)))

        self.out.write(data)

        self.out.flush()

        length = self.in_.read(4)

        length, = struct.unpack('>I', length)

        if length != 4:

            raise error.Abort(_('invalid response'))

        rc, = struct.unpack('>i', self.in_.read(4))

        return rc

_iochannels = [

    # server.ch, ui.fp, mode

    ('cin', 'fin', 'rb'),

    ('cout', 'fout', 'wb'),

    ('cerr', 'ferr', 'wb'),

]

class chgcmdserver(commandserver.server):

    def __init__(self, ui, repo, fin, fout, sock):

        super(chgcmdserver, self).__init__(

            _newchgui(ui, channeledsystem(fin, fout, 'S')), repo, fin, fout)

        self.clientsock = sock

        self._oldios = []  # original (self.ch, ui.fp, fd) before "attachio"

    def cleanup(self):

        # dispatch._runcatch() does not flush outputs if exception is not

        # handled by dispatch._dispatch()

        self.ui.flush()

        self._restoreio()

    def attachio(self):

        """Attach to client's stdio passed via unix domain socket; all

        channels except cresult will no longer be used

        """

        # tell client to sendmsg() with 1-byte payload, which makes it

        # distinctive from "attachio\n" command consumed by client.read()

        self.clientsock.sendall(struct.pack('>cI', 'I', 1))

        clientfds = osutil.recvfds(self.clientsock.fileno())

        _log('received fds: %r\n' % clientfds)

        ui = self.ui

        ui.flush()

        first = self._saveio()

        for fd, (cn, fn, mode) in zip(clientfds, _iochannels):

            assert fd > 0

            fp = getattr(ui, fn)

            os.dup2(fd, fp.fileno())

            os.close(fd)

            if not first:

                continue

            # reset buffering mode when client is first attached. as we want

            # to see output immediately on pager, the mode stays unchanged

            # when client re-attached. ferr is unchanged because it should

            # be unbuffered no matter if it is a tty or not.

            if fn == 'ferr':

                newfp = fp

            else:

                # make it line buffered explicitly because the default is

                # decided on first write(), where fout could be a pager.

                if fp.isatty():

                    bufsize = 1  # line buffered

                else:

                    bufsize = -1  # system default

                newfp = os.fdopen(fp.fileno(), mode, bufsize)

                setattr(ui, fn, newfp)

            setattr(self, cn, newfp)

        self.cresult.write(struct.pack('>i', len(clientfds)))

    def _saveio(self):

        if self._oldios:

            return False

        ui = self.ui

        for cn, fn, _mode in _iochannels:

            ch = getattr(self, cn)

            fp = getattr(ui, fn)

            fd = os.dup(fp.fileno())

            self._oldios.append((ch, fp, fd))

        return True

    def _restoreio(self):

        ui = self.ui

        for (ch, fp, fd), (cn, fn, _mode) in zip(self._oldios, _iochannels):

            newfp = getattr(ui, fn)

            # close newfp while it's associated with client; otherwise it

            # would be closed when newfp is deleted

            if newfp is not fp:

                newfp.close()

            # restore original fd: fp is open again

            os.dup2(fd, fp.fileno())

            os.close(fd)

            setattr(self, cn, ch)

            setattr(ui, fn, fp)

        del self._oldios[:]

    def chdir(self):

        """Change current directory

        Note that the behavior of --cwd option is bit different from this.

        It does not affect --config parameter.

        """

        path = self._readstr()

        if not path:

            return

        _log('chdir to %r\n' % path)

        os.chdir(path)

    def setumask(self):

        """Change umask"""

        mask = struct.unpack('>I', self._read(4))[0]

        _log('setumask %r\n' % mask)

        os.umask(mask)

    def getpager(self):

        """Read cmdargs and write pager command to r-channel if enabled

        If pager isn't enabled, this writes '\0' because channeledoutput

        does not allow to write empty data.

        """

        args = self._readlist()

        try:

            cmd, _func, args, options, _cmdoptions = dispatch._parse(self.ui,

                                                                     args)

        except (error.Abort, error.AmbiguousCommand, error.CommandError,

                error.UnknownCommand):

            cmd = None

            options = {}

        if not cmd or 'pager' not in options:

            self.cresult.write('\0')

            return

        pagercmd = _setuppagercmd(self.ui, options, cmd)

        if pagercmd:

            self.cresult.write(pagercmd)

        else:

            self.cresult.write('\0')

    def setenv(self):

        """Clear and update os.environ

        Note that not all variables can make an effect on the running process.

        """

        l = self._readlist()

        try:

            newenv = dict(s.split('=', 1) for s in l)

        except ValueError:

            raise ValueError('unexpected value in setenv request')

        diffkeys = set(k for k in set(os.environ.keys() + newenv.keys())

                       if os.environ.get(k) != newenv.get(k))

        _log('change env: %r\n' % sorted(diffkeys))

        os.environ.clear()

        os.environ.update(newenv)