share: don't recreate the source repo each time

Previously, every time you asked for the source repo of a shared working copy it
would recreate the repo object, which required calling reposetup. With certain
extension enabled, this can be quite expensive, and it can happen many times
(for instance, share attaches a post transaction hook to update bookmarks that
triggers this).

The fix is to just cache the repo object instead of constantly recreating it.

hgext/share.py

@@ -1,189 +1,194 b''
 # 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
 
 Automatic Pooled Storage for Clones
 -----------------------------------
 
 When this extension is active, :hg:`clone` can be configured to
 automatically share/pool storage across multiple clones. This
 mode effectively converts :hg:`clone` to :hg:`clone` + :hg:`share`.
 The benefit of using this mode is the automatic management of
 store paths and intelligent pooling of related repositories.
 
 The following ``share.`` config options influence this feature:
 
 ``share.pool``
     Filesystem path where shared repository data will be stored. When
     defined, :hg:`clone` will automatically use shared repository
     storage instead of creating a store inside each clone.
 
 ``share.poolnaming``
     How directory names in ``share.pool`` are constructed.
 
     "identity" means the name is derived from the first changeset in the
     repository. In this mode, different remotes share storage if their
     root/initial changeset is identical. In this mode, the local shared
     repository is an aggregate of all encountered remote repositories.
 
     "remote" means the name is derived from the source repository's
     path or URL. In this mode, storage is only shared if the path or URL
     requested in the :hg:`clone` command matches exactly to a repository
     that was cloned before.
 
     The default naming mode is "identity."
 '''
 
 from __future__ import absolute_import
 
 import errno
 from mercurial.i18n import _
 from mercurial import (
     bookmarks,
     cmdutil,
     commands,
     error,
     extensions,
     hg,
     util,
 )
 
 repository = hg.repository
 parseurl = hg.parseurl
 
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 # Note for extension authors: ONLY specify testedwith = 'internal' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'internal'
 
 @command('share',
     [('U', 'noupdate', None, _('do not create a working directory')),
      ('B', 'bookmarks', None, _('also share bookmarks'))],
     _('[-U] [-B] SOURCE [DEST]'),
     norepo=True)
 def share(ui, source, dest=None, noupdate=False, bookmarks=False):
     """create a new shared repository
 
     Initialize a new repository and working directory that shares its
     history (and optionally bookmarks) 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.
     """
 
     return hg.share(ui, source, dest=dest, update=not noupdate,
                     bookmarks=bookmarks)
 
 @command('unshare', [], '')
 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 not repo.shared():
         raise error.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, svfs and sjoin of repo
     repo.unfiltered().__init__(repo.baseui, repo.root)
 
 # Wrap clone command to pass auto share options.
 def clone(orig, ui, source, *args, **opts):
     pool = ui.config('share', 'pool', None)
     if pool:
         pool = util.expandpath(pool)
 
     opts['shareopts'] = dict(
         pool=pool,
         mode=ui.config('share', 'poolnaming', 'identity'),
     )
 
     return orig(ui, source, *args, **opts)
 
 def extsetup(ui):
     extensions.wrapfunction(bookmarks, '_getbkfile', getbkfile)
     extensions.wrapfunction(bookmarks.bmstore, 'recordchange', recordchange)
     extensions.wrapfunction(bookmarks.bmstore, '_writerepo', writerepo)
     extensions.wrapcommand(commands.table, 'clone', clone)
 
 def _hassharedbookmarks(repo):
     """Returns whether this repo has shared bookmarks"""
     try:
         shared = repo.vfs.read('shared').splitlines()
     except IOError as inst:
         if inst.errno != errno.ENOENT:
             raise
         return False
     return hg.sharedbookmarks in shared
 
 def _getsrcrepo(repo):
     """
     Returns the source repository object for a given shared repository.
     If repo is not a shared repository, return None.
     """
     if repo.sharedpath == repo.path:
         return None
 
+    if util.safehasattr(repo, 'srcrepo') and repo.srcrepo:
+        return repo.srcrepo
+
     # the sharedpath always ends in the .hg; we want the path to the repo
     source = repo.vfs.split(repo.sharedpath)[0]
     srcurl, branches = parseurl(source)
-    return repository(repo.ui, srcurl)
+    srcrepo = repository(repo.ui, srcurl)
+    repo.srcrepo = srcrepo
+    return srcrepo
 
 def getbkfile(orig, repo):
     if _hassharedbookmarks(repo):
         srcrepo = _getsrcrepo(repo)
         if srcrepo is not None:
             repo = srcrepo
     return orig(repo)
 
 def recordchange(orig, self, tr):
     # Continue with write to local bookmarks file as usual
     orig(self, tr)
 
     if _hassharedbookmarks(self._repo):
         srcrepo = _getsrcrepo(self._repo)
         if srcrepo is not None:
             category = 'share-bookmarks'
             tr.addpostclose(category, lambda tr: self._writerepo(srcrepo))
 
 def writerepo(orig, self, repo):
     # First write local bookmarks file in case we ever unshare
     orig(self, repo)
 
     if _hassharedbookmarks(self._repo):
         srcrepo = _getsrcrepo(self._repo)
         if srcrepo is not None:
             orig(self, srcrepo)