mercurial/lock.py
author Bryan O'Sullivan <bos@serpentine.com>
Sun, 07 Aug 2005 12:43:11 -0800
changeset 870 a82eae840447
parent 705 574869103985
child 1062 6d5a62a549fa
permissions -rw-r--r--
Teach walk code about absolute paths. The first consequence of this is that absolute and relative paths now all work in the same way. The second is that paths that lie outside the repository now cause an error to be reported, instead of something arbitrary and expensive being done. Internally, all of the serious work is in the util package. The new canonpath function takes an arbitrary path and either returns a canonical path or raises an error. Because it needs to know where the repository root is, it must be fed a repository or dirstate object, which has given commands.matchpats and friends a new parameter to pass along. The util.matcher function uses this to canonicalise globs and relative path names. Meanwhile, I've moved the Abort exception from commands to util, and killed off the redundant util.CommandError exception.

# 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