mercurial/lock.py
author Bryan O'Sullivan <bos@serpentine.com>
Fri, 29 Jul 2005 08:49:01 -0800
changeset 810 790a0ff306f2
parent 705 574869103985
child 1062 6d5a62a549fa
permissions -rw-r--r--
Move commands.forget over to using new walk code. With no names, it now recursively forgets everything, as is the default behaviour of other commands. And prints the names of all files it hasn't specifically been told to forget.

# 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