~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005 Canonical Ltd

# 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; either version 2 of the License, or

# (at your option) any later version.

#

# 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

__all__ = ['needs_read_lock',

           'needs_write_lock',

           ]

def needs_read_lock(unbound):

    """Decorate unbound to take out and release a read lock.

    This decorator can be applied to methods of any class with lock_read() and

    unlock() methods.

    Typical usage:

    class Branch(...):

        @needs_read_lock

        def branch_method(self, ...):

            stuff

    """

    def read_locked(self, *args, **kwargs):

        self.lock_read()

        try:

            return unbound(self, *args, **kwargs)

        finally:

            self.unlock()

    read_locked.__doc__ = unbound.__doc__

    read_locked.__name__ = unbound.__name__

    return read_locked

def needs_write_lock(unbound):

    """Decorate unbound to take out and release a write lock."""

    def write_locked(self, *args, **kwargs):

        self.lock_write()

        try:

            return unbound(self, *args, **kwargs)

        finally:

            self.unlock()

    write_locked.__doc__ = unbound.__doc__

    write_locked.__name__ = unbound.__name__

    return write_locked