diff options
Diffstat (limited to 'Demo/pdist/cvslock.py')
| -rwxr-xr-x | Demo/pdist/cvslock.py | 332 |
1 files changed, 166 insertions, 166 deletions
diff --git a/Demo/pdist/cvslock.py b/Demo/pdist/cvslock.py index 75f866e..8f6d008 100755 --- a/Demo/pdist/cvslock.py +++ b/Demo/pdist/cvslock.py @@ -22,25 +22,25 @@ a write lock is held. - To set a read lock: - - acquire the meta-lock - - create the file "#cvs.rfl.<pid>" - - release the meta-lock + - acquire the meta-lock + - create the file "#cvs.rfl.<pid>" + - release the meta-lock - To set a write lock: - - acquire the meta-lock - - check that there are no files called "#cvs.rfl.*" - - if there are, release the meta-lock, sleep, try again - - create the file "#cvs.wfl.<pid>" + - acquire the meta-lock + - check that there are no files called "#cvs.rfl.*" + - if there are, release the meta-lock, sleep, try again + - create the file "#cvs.wfl.<pid>" - To release a write lock: - - remove the file "#cvs.wfl.<pid>" - - rmdir the meta-lock + - remove the file "#cvs.wfl.<pid>" + - rmdir the meta-lock - To release a read lock: - - remove the file "#cvs.rfl.<pid>" + - remove the file "#cvs.rfl.<pid>" Additional notes @@ -93,188 +93,188 @@ CVSWFL = "#cvs.wfl." class Error: - def __init__(self, msg): - self.msg = msg + def __init__(self, msg): + self.msg = msg - def __repr__(self): - return repr(self.msg) + def __repr__(self): + return repr(self.msg) - def __str__(self): - return str(self.msg) + def __str__(self): + return str(self.msg) class Locked(Error): - pass + pass class Lock: - def __init__(self, repository = ".", delay = DELAY): - self.repository = repository - self.delay = delay - self.lockdir = None - self.lockfile = None - pid = repr(os.getpid()) - self.cvslck = self.join(CVSLCK) - self.cvsrfl = self.join(CVSRFL + pid) - self.cvswfl = self.join(CVSWFL + pid) - - def __del__(self): - print "__del__" - self.unlock() - - def setlockdir(self): - while 1: - try: - self.lockdir = self.cvslck - os.mkdir(self.cvslck, 0777) - return - except os.error, msg: - self.lockdir = None - if msg[0] == EEXIST: - try: - st = os.stat(self.cvslck) - except os.error: - continue - self.sleep(st) - continue - raise Error("failed to lock %s: %s" % ( - self.repository, msg)) - - def unlock(self): - self.unlockfile() - self.unlockdir() - - def unlockfile(self): - if self.lockfile: - print "unlink", self.lockfile - try: - os.unlink(self.lockfile) - except os.error: - pass - self.lockfile = None - - def unlockdir(self): - if self.lockdir: - print "rmdir", self.lockdir - try: - os.rmdir(self.lockdir) - except os.error: - pass - self.lockdir = None - - def sleep(self, st): - sleep(st, self.repository, self.delay) - - def join(self, name): - return os.path.join(self.repository, name) + def __init__(self, repository = ".", delay = DELAY): + self.repository = repository + self.delay = delay + self.lockdir = None + self.lockfile = None + pid = repr(os.getpid()) + self.cvslck = self.join(CVSLCK) + self.cvsrfl = self.join(CVSRFL + pid) + self.cvswfl = self.join(CVSWFL + pid) + + def __del__(self): + print "__del__" + self.unlock() + + def setlockdir(self): + while 1: + try: + self.lockdir = self.cvslck + os.mkdir(self.cvslck, 0777) + return + except os.error, msg: + self.lockdir = None + if msg[0] == EEXIST: + try: + st = os.stat(self.cvslck) + except os.error: + continue + self.sleep(st) + continue + raise Error("failed to lock %s: %s" % ( + self.repository, msg)) + + def unlock(self): + self.unlockfile() + self.unlockdir() + + def unlockfile(self): + if self.lockfile: + print "unlink", self.lockfile + try: + os.unlink(self.lockfile) + except os.error: + pass + self.lockfile = None + + def unlockdir(self): + if self.lockdir: + print "rmdir", self.lockdir + try: + os.rmdir(self.lockdir) + except os.error: + pass + self.lockdir = None + + def sleep(self, st): + sleep(st, self.repository, self.delay) + + def join(self, name): + return os.path.join(self.repository, name) def sleep(st, repository, delay): - if delay <= 0: - raise Locked(st) - uid = st[stat.ST_UID] - try: - pwent = pwd.getpwuid(uid) - user = pwent[0] - except KeyError: - user = "uid %d" % uid - print "[%s]" % time.ctime(time.time())[11:19], - print "Waiting for %s's lock in" % user, repository - time.sleep(delay) + if delay <= 0: + raise Locked(st) + uid = st[stat.ST_UID] + try: + pwent = pwd.getpwuid(uid) + user = pwent[0] + except KeyError: + user = "uid %d" % uid + print "[%s]" % time.ctime(time.time())[11:19], + print "Waiting for %s's lock in" % user, repository + time.sleep(delay) class ReadLock(Lock): - def __init__(self, repository, delay = DELAY): - Lock.__init__(self, repository, delay) - ok = 0 - try: - self.setlockdir() - self.lockfile = self.cvsrfl - fp = open(self.lockfile, 'w') - fp.close() - ok = 1 - finally: - if not ok: - self.unlockfile() - self.unlockdir() + def __init__(self, repository, delay = DELAY): + Lock.__init__(self, repository, delay) + ok = 0 + try: + self.setlockdir() + self.lockfile = self.cvsrfl + fp = open(self.lockfile, 'w') + fp.close() + ok = 1 + finally: + if not ok: + self.unlockfile() + self.unlockdir() class WriteLock(Lock): - def __init__(self, repository, delay = DELAY): - Lock.__init__(self, repository, delay) - self.setlockdir() - while 1: - uid = self.readers_exist() - if not uid: - break - self.unlockdir() - self.sleep(uid) - self.lockfile = self.cvswfl - fp = open(self.lockfile, 'w') - fp.close() - - def readers_exist(self): - n = len(CVSRFL) - for name in os.listdir(self.repository): - if name[:n] == CVSRFL: - try: - st = os.stat(self.join(name)) - except os.error: - continue - return st - return None + def __init__(self, repository, delay = DELAY): + Lock.__init__(self, repository, delay) + self.setlockdir() + while 1: + uid = self.readers_exist() + if not uid: + break + self.unlockdir() + self.sleep(uid) + self.lockfile = self.cvswfl + fp = open(self.lockfile, 'w') + fp.close() + + def readers_exist(self): + n = len(CVSRFL) + for name in os.listdir(self.repository): + if name[:n] == CVSRFL: + try: + st = os.stat(self.join(name)) + except os.error: + continue + return st + return None def MultipleWriteLock(repositories, delay = DELAY): - while 1: - locks = [] - for r in repositories: - try: - locks.append(WriteLock(r, 0)) - except Locked, instance: - del locks - break - else: - break - sleep(instance.msg, r, delay) - return list + while 1: + locks = [] + for r in repositories: + try: + locks.append(WriteLock(r, 0)) + except Locked, instance: + del locks + break + else: + break + sleep(instance.msg, r, delay) + return list def test(): - import sys - if sys.argv[1:]: - repository = sys.argv[1] - else: - repository = "." - rl = None - wl = None - try: - print "attempting write lock ..." - wl = WriteLock(repository) - print "got it." - wl.unlock() - print "attempting read lock ..." - rl = ReadLock(repository) - print "got it." - rl.unlock() - finally: - print [1] - sys.exc_traceback = None - print [2] - if rl: - rl.unlock() - print [3] - if wl: - wl.unlock() - print [4] - rl = None - print [5] - wl = None - print [6] + import sys + if sys.argv[1:]: + repository = sys.argv[1] + else: + repository = "." + rl = None + wl = None + try: + print "attempting write lock ..." + wl = WriteLock(repository) + print "got it." + wl.unlock() + print "attempting read lock ..." + rl = ReadLock(repository) + print "got it." + rl.unlock() + finally: + print [1] + sys.exc_traceback = None + print [2] + if rl: + rl.unlock() + print [3] + if wl: + wl.unlock() + print [4] + rl = None + print [5] + wl = None + print [6] if __name__ == '__main__': - test() + test() |