mercurial/lock.py
author Thomas Arendsen Hein <thomas@intevation.de>
Wed, 10 Aug 2005 06:47:46 +0100
changeset 862 d70c1c31fd45
parent 705 574869103985
child 1062 6d5a62a549fa
permissions -rw-r--r--
Fix 3-way-merge of original parent, workdir and new parent. The dirstate has to match what is in the repository (what would be checked out with 'hg update -C'), because the resulting file may be identical to the new parent, or it may be completely different. Previously the dirstate wasn't updated, so if you changed the file to look like the original parent, it might be considered unmodified relative to the new parent.

# 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