mercurial/lock.py
author Thomas Arendsen Hein <thomas@intevation.de>
Fri, 15 Jul 2005 13:42:19 +0100
changeset 712 b4f0fad0ea64
parent 705 574869103985
child 1062 6d5a62a549fa
permissions -rw-r--r--
Merge with myself. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Merge with myself. manifest hash: e47e1ba87ecb28a08f819401fd8c2a88bc830261 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQFC168rW7P1GVgWeRoRAmknAJ0ea1BrnM1KSnfPqkYpurFpV+booACcDGNh ka6ciaH1pQLhOyKgqdbqwOA= =pOV4 -----END PGP SIGNATURE-----

# lock.py - simple locking scheme for mercurial
#
# Copyright 2005 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

import os, time
import util

class LockHeld(Exception):
    pass

class lock:
    def __init__(self, file, wait = 1):
        self.f = file
        self.held = 0
        self.wait = wait
        self.lock()

    def __del__(self):
        self.release()

    def lock(self):
        while 1:
            try:
                self.trylock()
                return 1
            except LockHeld, inst:
                if self.wait:
                    time.sleep(1)
                    continue
                raise inst

    def trylock(self):
        pid = os.getpid()
        try:
            util.makelock(str(pid), self.f)
            self.held = 1
        except (OSError, IOError):
            raise LockHeld(util.readlock(self.f))

    def release(self):
        if self.held:
            self.held = 0
            try:
                os.unlink(self.f)
            except: pass