:copyright: (C) 2009-2011 Marcin Kuzminski <marcin@python-works.com>    

    :license: GPLv3, see COPYING for more details.

"""

# 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; version 2

# of the License or (at your opinion) any later version of the license.

# 

# 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, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

# MA  02110-1301, USA.

import platform

VERSION = (1, 2, 0, 'beta')

__version__ = '.'.join((str(each) for each in VERSION[:4]))

__dbversion__ = 3 #defines current db version for migrations

__platform__ = platform.system()

try:

    from rhodecode.lib.utils import get_current_revision

    _rev = get_current_revision()

except ImportError:

    #this is needed when doing some setup.py operations

    _rev = False

if len(VERSION) > 3 and _rev:

    __version__ += ' [rev:%s]' % _rev[0]

def get_version():

    """Returns shorter version (digit parts only) as string."""

    return '.'.join((str(each) for each in VERSION[:3]))

BACKENDS = {

    'hg': 'Mercurial repository',

    #'git': 'Git repository',

}

import os, time

import sys

from warnings import warn

from multiprocessing.util import Finalize

import errno

class LockHeld(Exception):pass

class DaemonLock(object):

    """daemon locking

    USAGE:

    try:

        l = DaemonLock(desc='test lock')

        main()

        l.release()

    except LockHeld:

        sys.exit(1)

    """

    def __init__(self, file=None, callbackfn=None,

                 desc='daemon lock', debug=False):

        self.pidfile = file if file else os.path.join(os.path.dirname(__file__),

                                                      'running.lock')

        self.callbackfn = callbackfn

        self.desc = desc

        self.debug = debug

        self.held = False

        #run the lock automatically !

        if lock.held:

            if debug:

                print 'leck held finilazing and running lock.release()'

            lock.release()

    def lock(self):

        """locking function, if lock is present it will raise LockHeld exception

        """

        lockname = '%s' % (os.getpid())

        if self.debug:

            print 'running lock'

        self.trylock()

        self.makelock(lockname, self.pidfile)

        return True

    def trylock(self):

        running_pid = False

        if self.debug:

            print 'checking for already running process'

        try:

            pidfile = open(self.pidfile, "r")

            pidfile.seek(0)

            running_pid = int(pidfile.readline())

            pidfile.close()

            if self.debug:

                print 'lock file present running_pid: %s, checking for execution'\

                % running_pid

            # Now we check the PID from lock file matches to the current

            # process PID

            if running_pid:

                try:

                except OSError, exc:

                    if exc.errno in (errno.ESRCH, errno.EPERM):

                        print "Lock File is there but the program is not running"

                        self.release()

                    else:

                        raise

                else:

                    print "You already have an instance of the program running"

                    raise LockHeld()

        except IOError, e:

            if e.errno != 2:

                raise

    def release(self):

        """releases the pid by removing the pidfile

        """

        if self.debug:

            print 'trying to release the pidlock'

        if self.callbackfn:

            #execute callback function on release

            if self.debug:

                print 'executing callback function %s' % self.callbackfn

            self.callbackfn()

        try:

            if self.debug:

                print 'removing pidfile %s' % self.pidfile

            os.remove(self.pidfile)

            self.held = False

        except OSError, e:

            if self.debug:

                print 'removing pidfile failed %s' % e

            pass

    def makelock(self, lockname, pidfile):

        """

        this function will make an actual lock

        :param lockname: acctual pid of file

        :param pidfile: the file to write the pid in

        """

        if self.debug:

            print 'creating a file %s and pid: %s' % (pidfile, lockname)

        pidfile = open(self.pidfile, "wb")