mercurial/lock.py
author mpm@selenic.com
Tue, 31 May 2005 21:10:10 -0800
changeset 201 f918a6fa2572
parent 161 0b4c5cb953d9
child 422 10c43444a38e
child 429 688d03d6997a
permissions -rw-r--r--
hgweb: add template filters, template style maps, and raw pages -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 hgweb: add template filters, template style maps, and raw pages Template filters: in templates, you can now specify a chain of filters like #desc|firstline|escape# #desc|escape|addbreaks# #date|age# to specify how you'd like raw text (or whatever) to be transformed. Template style maps: add ;style=foo to a URL and we'll use templates/map-foo if it exists. Raw output: Together, these two features make it east to implement raw downloadable files and patches. Simply link to the same page with style=raw and present the output as unfiltered text/plain with that template. manifest hash: 5954a648b3d6b4e6dc2dcd1975f96b4b0178da2a -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) iD8DBQFCnUMyywK+sNU5EO8RAkKjAJ9h9JElSCbWBPUnL+koCSDxgo38AwCgrccM 0qwyKdh/fUNglICxSh3HBNA= =Svlo -----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

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:
            os.symlink(str(pid), self.f)
            self.held = 1
        except:
            raise LockHeld(os.readlink(self.f))

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