mercurial/lock.py
author mpm@selenic.com
Thu, 30 Jun 2005 21:28:18 -0800
changeset 537 411e05b04ffa
parent 515 03f27b1381f9
child 704 5ca319a641e1
child 705 574869103985
permissions -rw-r--r--
Propagate file list through dodiff -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Propagate file list through dodiff This speeds up operations like 'hg diff Makefile'. Previously it would walk the entire directory tree looking for changes. Now it will only stat Makefile. Further, if Makefile appears untouched, it will skip reading the manifest. manifest hash: ab22a70a5511ed2d7a647f2cd15d129a88dccabf -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) iD8DBQFCxNRyywK+sNU5EO8RAgb6AKC2TzWmRjNsWq0Q9Pa+ppCZ6Y+pdwCfdHUA UHu024/2Wt6C6WZ5vcWfPbo= =E35L -----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:
            raise LockHeld(util.readlock(self.f))

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