# server.py - utility and factory of server

#

# Copyright 2005-2007 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 errno

import os

import sys

import tempfile

from .i18n import _

from . import (

    error,

    util,

)

def runservice(opts, parentfn=None, initfn=None, runfn=None, logfile=None,

               runargs=None, appendpid=False):

    '''Run a command as a service.'''

    def writepid(pid):

        if opts['pid_file']:

            if appendpid:

                mode = 'a'

            else:

                mode = 'w'

            fp = open(opts['pid_file'], mode)

            fp.write(str(pid) + '\n')

            fp.close()

    if opts['daemon'] and not opts['daemon_postexec']:

        # Signal child process startup with file removal

        lockfd, lockpath = tempfile.mkstemp(prefix='hg-service-')

        os.close(lockfd)

        try:

            if not runargs:

                runargs = util.hgcmd() + sys.argv[1:]

            runargs.append('--daemon-postexec=unlink:%s' % lockpath)

            # Don't pass --cwd to the child process, because we've already

            # changed directory.

            for i in xrange(1, len(runargs)):

                if runargs[i].startswith('--cwd='):

                    del runargs[i]

                    break

                elif runargs[i].startswith('--cwd'):

                    del runargs[i:i + 2]

                    break

            def condfn():

                return not os.path.exists(lockpath)

            pid = util.rundetached(runargs, condfn)

            if pid < 0:

                raise error.Abort(_('child process failed to start'))

            writepid(pid)

        finally:

            try:

                os.unlink(lockpath)

            except OSError as e:

                if e.errno != errno.ENOENT:

                    raise

        if parentfn:

            return parentfn(pid)

        else:

            return

    if initfn:

        initfn()

    if not opts['daemon']:

        writepid(util.getpid())

    if opts['daemon_postexec']:

        try:

            os.setsid()

        except AttributeError:

            pass

        for inst in opts['daemon_postexec']:

            if inst.startswith('unlink:'):

                lockpath = inst[7:]

                os.unlink(lockpath)

            elif inst.startswith('chdir:'):

                os.chdir(inst[6:])

            elif inst != 'none':

                raise error.Abort(_('invalid value for --daemon-postexec: %s')

                                  % inst)

        util.hidewindow()

        util.stdout.flush()

        util.stderr.flush()

        nullfd = os.open(os.devnull, os.O_RDWR)

        logfilefd = nullfd

        if logfile:

            logfilefd = os.open(logfile, os.O_RDWR | os.O_CREAT | os.O_APPEND)

        os.dup2(nullfd, 0)

        os.dup2(logfilefd, 1)

        os.dup2(logfilefd, 2)

        if nullfd not in (0, 1, 2):

            os.close(nullfd)

        if logfile and logfilefd not in (0, 1, 2):

            os.close(logfilefd)

    if runfn:

        return runfn()