# Source code for taurus.core.util.lock

    #!/usr/bin/env python

    # ###########################################################################
    #
    # This file is part of Taurus
    #
    # http://taurus-scada.org
    #
    # Copyright 2011 CELLS / ALBA Synchrotron, Bellaterra, Spain
    #
    # Taurus is free software: you can redistribute it and/or modify
    # it under the terms of the GNU Lesser General Public License as published by
    # the Free Software Foundation, either version 3 of the License, or
    # (at your option) any later version.
    #
    # Taurus 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 Lesser General Public License for more details.
    #
    # You should have received a copy of the GNU Lesser General Public License
    # along with Taurus.  If not, see <http://www.gnu.org/licenses/>.
    #
    # ###########################################################################

    """This module defines a *slow* lock class that provides additional debugging
    information
    """

    import threading
    import logging

    __all__ = ["TaurusLock"]

    __docformat__ = "restructuredtext"

    _VERBOSE = False

    def TaurusLock(verbose=None, name=None, lock=None):
        if verbose is None:
            verbose = _VERBOSE
        if verbose:
            return _TaurusLock(name=name, lock=lock)
        if lock is None:
            return threading.Lock()
        return lock

    class _TaurusLock(object):
        """A sardana lock"""

        def __init__(self, name=None, lock=None, level=logging.DEBUG):
            name = name or self.__class__.__name__
            self.__name = name
            self.__logger = logging.getLogger(name=name)
            self.__level = level
            if lock is None:
                lock = threading.Lock()
            self.__block = lock
            self.__owner = None

        def __repr__(self):
            owner = self.__owner
            if owner is not None:
                owner = owner.name
            return "<%s owner=%r>" % (self.__name, owner)

        def owner_name(self):
            owner = self.__owner
            if owner is not None:
                return owner.name

        def _note(self, msg, *args):
            self.__logger.log(self.__level, msg, *args)

        def acquire(self, blocking=1):
            if __debug__:
                self._note(
                    "[START] acquire(%s) [owner=%s]", blocking, self.owner_name()
                )
            rc = self.__block.acquire(blocking)
            me = threading.current_thread()
            if rc:
                self.__owner = me
                state = "success"
            else:
                state = "failure"
            if __debug__:
                self._note(
                    "[ END ] acquire(%s) %s [owner=%s]",
                    blocking,
                    state,
                    self.owner_name(),
                )
            return rc

        __enter__ = acquire

        def release(self):
            if __debug__:
                self._note("[START] release() [owner=%s]", self.owner_name())
            self.__block.release()
            self.__owner = None
            if __debug__:
                self._note("[ END ] release() [owner=%s]", self.owner_name())

        def __exit__(self, t, v, tb):
            self.release()