hgweb.manifest: revno of manifest and changelog aren't always the same
In the v4l-dvb repo, the manifest revno and the changelog revno are not
in sync. This happened because the same patch was applied to the same
revision in two different branches, resulting in the same manifest text,
with the same parents and so the first revision was reused.
Since hgweb.manifest was assuming the revnos of the manifest and of the
changelog were always the same, clicking on manifest -> bz2 in the
v4l-dvb site would download the wrong revision.
Use the linkrev to go from manifest revision to changelog revision.
This still won't be perfect since the page will still talk about
"manifest for changeset XYZ", where XYZ was the first changeset to have
this manifest, which is not necessarily the same changeset that the user
clicked to get to this page - but at least the contents will be the
same.
# 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.
from demandload import *
demandload(globals(), 'errno os socket time util')
class LockException(IOError):
def __init__(self, errno, strerror, filename, desc):
IOError.__init__(self, errno, strerror, filename)
self.desc = desc
class LockHeld(LockException):
def __init__(self, errno, filename, desc, locker):
LockException.__init__(self, errno, 'Lock held', filename, desc)
self.locker = locker
class LockUnavailable(LockException):
pass
class lock(object):
# lock is symlink on platforms that support it, file on others.
# symlink is used because create of directory entry and contents
# are atomic even over nfs.
# old-style lock: symlink to pid
# new-style lock: symlink to hostname:pid
def __init__(self, file, timeout=-1, releasefn=None, desc=None):
self.f = file
self.held = 0
self.timeout = timeout
self.releasefn = releasefn
self.id = None
self.host = None
self.pid = None
self.desc = desc
self.lock()
def __del__(self):
self.release()
def lock(self):
timeout = self.timeout
while 1:
try:
self.trylock()
return 1
except LockHeld, inst:
if timeout != 0:
time.sleep(1)
if timeout > 0:
timeout -= 1
continue
raise LockHeld(errno.ETIMEDOUT, inst.filename, self.desc,
inst.locker)
def trylock(self):
if self.id is None:
self.host = socket.gethostname()
self.pid = os.getpid()
self.id = '%s:%s' % (self.host, self.pid)
while not self.held:
try:
util.makelock(self.id, self.f)
self.held = 1
except (OSError, IOError), why:
if why.errno == errno.EEXIST:
locker = self.testlock()
if locker:
raise LockHeld(errno.EAGAIN, self.f, self.desc,
locker)
else:
raise LockUnavailable(why.errno, why.strerror,
why.filename, self.desc)
def testlock(self):
'''return id of locker if lock is valid, else None.'''
# if old-style lock, we cannot tell what machine locker is on.
# with new-style lock, if locker is on this machine, we can
# see if locker is alive. if locker is on this machine but
# not alive, we can safely break lock.
locker = util.readlock(self.f)
c = locker.find(':')
if c == -1:
return locker
host = locker[:c]
if host != self.host:
return locker
try:
pid = int(locker[c+1:])
except:
return locker
if util.testpid(pid):
return locker
# if locker dead, break lock. must do this with another lock
# held, or can race and break valid lock.
try:
l = lock(self.f + '.break')
l.trylock()
os.unlink(self.f)
l.release()
except (LockHeld, LockUnavailable):
return locker
def release(self):
if self.held:
self.held = 0
if self.releasefn:
self.releasefn()
try:
os.unlink(self.f)
except: pass