mercurial/lock.py
author Bryan O'Sullivan <bos@serpentine.com>
Fri, 29 Jul 2005 15:02:27 -0800
changeset 813 80fd2958235a
parent 705 574869103985
child 1062 6d5a62a549fa
permissions -rw-r--r--
Adapt commit to use file matching code. The code is slightly complicated by the need to commit all outstanding changes in the repository if no file names are given (other commands operate on the current directory and its subdirectories in this case). localrepository.changes has acquired an optional match parameter, to let it filter out include/exclude options.

# 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