Mercurial > hg > mercurial-crew-with-dirclash
view mercurial/lock.py @ 1698:ad4a2eefe4d7
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author | Matt Mackall <mpm@selenic.com> |
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date | Sun, 05 Feb 2006 22:21:02 -0600 |
parents | 59b3639df0a9 |
children | e6e70450edb9 |
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# 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(object): def __init__(self, file, wait=1, releasefn=None): self.f = file self.held = 0 self.wait = wait self.releasefn = releasefn 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 if self.releasefn: self.releasefn() try: os.unlink(self.f) except: pass