Mercurial > hg
view mercurial/lock.py @ 1740:f95654385065
add --daemon option to serve command. for issue 45.
code looks odd because it is portable to windows. windows does not have
os.fork, so have to spawn and use pipe to tell parent ready instead.
author | Vadim Gelfer <vadim.gelfer@gmail.com> |
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date | Fri, 17 Feb 2006 16:29:30 -0800 |
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