mercurial/lock.py
author mpm@selenic.com
Thu, 02 Jun 2005 18:46:49 -0800
changeset 222 87484f627422
parent 161 0b4c5cb953d9
child 422 10c43444a38e
child 429 688d03d6997a
permissions -rw-r--r--
make pull work for multiple heads -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 make pull work for multiple heads add repository.heads() teach remoterepository and hgweb about heads command teach getchangegroup about multiple heads break apart addchangegroup and merge (cleaning up merge saved for later) after this change, it is now possible to pull and get multiple heads, but not possible to merge the heads manifest hash: 86fe3ede296254698fdd4c97df02944993ef2cbb -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) iD8DBQFCn8SZywK+sNU5EO8RAkSvAJ9NOA4UZ3cFyyzymlYBZnV+PpGRcACeLL+R PFaSgJHGKvxsXpvPYiZA0O0= =L2Xr -----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)