annotate hgext/share.py @ 16175:280e834c9d15 stable

log: restore cache used by --copies

The {filelog -> linkrev -> copyfrom} cache was refactored and broken by:

  changeset:   10060:f780b1098efc
  user:        Patrick Mezard <[e-mail]>
  date:        Sun Dec 13 18:06:24 2009 +0100
  summary:     templatekw: change {file_copies} behaviour, add
               {file_copies_switch}

With --copies, this cache is accessed for every touched file of every revision.
Unfortunately it is recreated for every revision, which means filelogs are
parsed again. This patch makes the cache global again for all revisions.

A couple of indicative timings of "hg log --copies", before and after:

hg:                       44s /     5s
mozilla --limit 10000:  3m51s /  2m32s
mozilla:               23m46s / 12m23s

I do not know any good tool to trace memory consumption of these runs for
comparisons. Watching the full mozilla run in top, the process did not seem to
misbehave.

# Copyright 2006, 2007 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''share a common history between several working directories'''

from mercurial.i18n import _
from mercurial import hg, commands, util

def share(ui, source, dest=None, noupdate=False):
    """create a new shared repository

    Initialize a new repository and working directory that shares its
    history with another repository.

    .. note::
       using rollback or extensions that destroy/modify history (mq,
       rebase, etc.) can cause considerable confusion with shared
       clones. In particular, if two shared clones are both updated to
       the same changeset, and one of them destroys that changeset
       with rollback, the other clone will suddenly stop working: all
       operations will fail with "abort: working directory has unknown
       parent". The only known workaround is to use debugsetparents on
       the broken clone to reset it to a changeset that still exists
       (e.g. tip).
    """

    return hg.share(ui, source, dest, not noupdate)

def unshare(ui, repo):
    """convert a shared repository to a normal one

    Copy the store data to the repo and remove the sharedpath data.
    """

    if repo.sharedpath == repo.path:
        raise util.Abort(_("this is not a shared repo"))

    destlock = lock = None
    lock = repo.lock()
    try:
        # we use locks here because if we race with commit, we
        # can end up with extra data in the cloned revlogs that's
        # not pointed to by changesets, thus causing verify to
        # fail

        destlock = hg.copystore(ui, repo, repo.path)

        sharefile = repo.join('sharedpath')
        util.rename(sharefile, sharefile + '.old')

        repo.requirements.discard('sharedpath')
        repo._writerequirements()
    finally:
        destlock and destlock.release()
        lock and lock.release()

    # update store, spath, sopener and sjoin of repo
    repo.__init__(ui, repo.root)

cmdtable = {
    "share":
    (share,
     [('U', 'noupdate', None, _('do not create a working copy'))],
     _('[-U] SOURCE [DEST]')),
    "unshare":
    (unshare,
    [],
    ''),
}

commands.norepo += " share"