Mercurial > hg > mercurial-crew-with-dirclash
view mercurial/lock.py @ 1828:ca82f20b0c19
merge with crew.
author | Vadim Gelfer <vadim.gelfer@gmail.com> |
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date | Fri, 03 Mar 2006 08:44:37 -0800 |
parents | e431344e604c |
children | cd5c1db2132a |
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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 errno, os, time import util class LockException(Exception): pass class LockHeld(LockException): pass class LockUnavailable(LockException): pass class lock(object): def __init__(self, file, timeout=-1, releasefn=None): self.f = file self.held = 0 self.timeout = timeout self.releasefn = releasefn self.lock() def __del__(self): self.release() def lock(self): timeout = self.timeout while 1: try: self.trylock() return 1 except LockHeld, inst: if timeout != 0: time.sleep(1) if timeout > 0: timeout -= 1 continue raise inst def trylock(self): pid = os.getpid() try: util.makelock(str(pid), self.f) self.held = 1 except (OSError, IOError), why: if why.errno == errno.EEXIST: raise LockHeld(util.readlock(self.f)) else: raise LockUnavailable(why) def release(self): if self.held: self.held = 0 if self.releasefn: self.releasefn() try: os.unlink(self.f) except: pass