Mercurial > hg
view mercurial/lock.py @ 17758:5863f0e4cd3a
histedit: replace various nodes lists with replacement graph (and issue3582)
This changeset rewrites the change tracking logic of histedit to record every
operation it does. Tracked operations record the full list of "old" node that
will eventually be removed to the list of new nodes that replace it. Operations
on temporary nodes are tracked too. Dropped changesets are also recorded as an
"old" node replacement by nothing. This logic is similar to the obsolescence
marker one and will be used for this purpose in later commit.
This new logic implies a big amount of change in the histedit code base.
histedit action functions now always return a tuple of
(new-ctx, [list of rewriting operations])
The old `created`, `replaced` and `tmpnodes` are no longer returned and stored
during histedit operation. When such information is necessary it is computed
from the replacement graph. This computation is done in the `processreplacement`
function.
The `replacemap` is also dropped. It is computed at the end of the command from the
graph. The `bootstrapcontinue` methods are altered to compute this different kind of
information.
This new mechanism requires much less information to be written on disk.
Note:
This changes allows a more accurate bookmark movement. bookmark on dropped
changeset are now move of their parent (or replacement of their parent)
instead of their children.
This fix issue3582
author | Pierre-Yves David <pierre-yves.david@ens-lyon.org> |
---|---|
date | Thu, 11 Oct 2012 08:36:50 +0200 |
parents | 6d7db5794e8c |
children | af9fa8d4c939 |
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# lock.py - simple advisory locking scheme for mercurial # # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. import util, error import errno, os, socket, time import warnings class lock(object): '''An advisory lock held by one process to control access to a set of files. Non-cooperating processes or incorrectly written scripts can ignore Mercurial's locking scheme and stomp all over the repository, so don't do that. Typically used via localrepository.lock() to lock the repository store (.hg/store/) or localrepository.wlock() to lock everything else under .hg/.''' # 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 _host = None def __init__(self, file, timeout=-1, releasefn=None, desc=None): self.f = file self.held = 0 self.timeout = timeout self.releasefn = releasefn self.desc = desc self.postrelease = [] self.lock() def __del__(self): if self.held: warnings.warn("use lock.release instead of del lock", category=DeprecationWarning, stacklevel=2) # ensure the lock will be removed # even if recursive locking did occur self.held = 1 self.release() def lock(self): timeout = self.timeout while True: try: self.trylock() return 1 except error.LockHeld, inst: if timeout != 0: time.sleep(1) if timeout > 0: timeout -= 1 continue raise error.LockHeld(errno.ETIMEDOUT, inst.filename, self.desc, inst.locker) def trylock(self): if self.held: self.held += 1 return if lock._host is None: lock._host = socket.gethostname() lockname = '%s:%s' % (lock._host, os.getpid()) while not self.held: try: util.makelock(lockname, self.f) self.held = 1 except (OSError, IOError), why: if why.errno == errno.EEXIST: locker = self.testlock() if locker is not None: raise error.LockHeld(errno.EAGAIN, self.f, self.desc, locker) else: raise error.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. The lock file is only deleted when None is returned. """ try: locker = util.readlock(self.f) except OSError, why: if why.errno == errno.ENOENT: return None raise try: host, pid = locker.split(":", 1) except ValueError: return locker if host != lock._host: return locker try: pid = int(pid) except ValueError: 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', timeout=0) util.unlink(self.f) l.release() except error.LockError: return locker def release(self): """release the lock and execute callback function if any If the lock has been acquired multiple times, the actual release is delayed to the last release call.""" if self.held > 1: self.held -= 1 elif self.held == 1: self.held = 0 if self.releasefn: self.releasefn() try: util.unlink(self.f) except OSError: pass for callback in self.postrelease: callback() def release(*locks): for lock in locks: if lock is not None: lock.release()