Mercurial > hg > mercurial-crew-with-dirclash
comparison mercurial/lock.py @ 161:0b4c5cb953d9
Simply repository locking
This is a first pass at implementing repo locking. Next up, journal
recovery and undo.
author | mpm@selenic.com |
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date | Thu, 26 May 2005 08:53:04 -0800 |
parents | |
children | 10c43444a38e 688d03d6997a |
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160:5c331d941c7f | 161:0b4c5cb953d9 |
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1 # lock.py - simple locking scheme for mercurial | |
2 # | |
3 # Copyright 2005 Matt Mackall <mpm@selenic.com> | |
4 # | |
5 # This software may be used and distributed according to the terms | |
6 # of the GNU General Public License, incorporated herein by reference. | |
7 | |
8 import os, time | |
9 | |
10 class LockHeld(Exception): | |
11 pass | |
12 | |
13 class lock: | |
14 def __init__(self, file, wait = 1): | |
15 self.f = file | |
16 self.held = 0 | |
17 self.wait = wait | |
18 self.lock() | |
19 | |
20 def __del__(self): | |
21 self.release() | |
22 | |
23 def lock(self): | |
24 while 1: | |
25 try: | |
26 self.trylock() | |
27 return 1 | |
28 except LockHeld, inst: | |
29 if self.wait: | |
30 time.sleep(1) | |
31 continue | |
32 raise inst | |
33 | |
34 def trylock(self): | |
35 pid = os.getpid() | |
36 try: | |
37 os.symlink(str(pid), self.f) | |
38 self.held = 1 | |
39 except: | |
40 raise LockHeld(os.readlink(self.f)) | |
41 | |
42 def release(self): | |
43 if self.held: | |
44 self.held = 0 | |
45 os.unlink(self.f) | |
46 |