share: use the 'sharedpath' attr on repo instead of reloading from the file

Seems like a useful optimization, and now the exact file content is not a
concern.

hgext/share.py

@@ -1,130 +1,125
 # 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 cmdutil, hg, util, extensions, bookmarks
 from mercurial.hg import repository, parseurl
 import errno
 
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 testedwith = 'internal'
 
 @command('share',
     [('U', 'noupdate', None, _('do not create a working copy')),
      ('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, not noupdate, 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 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.unfiltered().__init__(repo.baseui, repo.root)
 
 def extsetup(ui):
     extensions.wrapfunction(bookmarks.bmstore, 'getbkfile', getbkfile)
     extensions.wrapfunction(bookmarks.bmstore, 'recordchange', recordchange)
     extensions.wrapfunction(bookmarks.bmstore, 'write', write)
 
 def _hassharedbookmarks(repo):
     """Returns whether this repo has shared bookmarks"""
     try:
         repo.vfs.read('bookmarks.shared')
         return True
     except IOError, inst:
         if inst.errno != errno.ENOENT:
             raise
         return False
 
 def _getsrcrepo(repo):
     """
     Returns the source repository object for a given shared repository.
     If repo is not a shared repository, return None.
     """
-    srcrepo = None
-    try:
-        # strip because some tools write with newline after
-        sharedpath = repo.vfs.read('sharedpath').strip()
-        # the sharedpath always ends in the .hg; we want the path to the repo
-        source = repo.vfs.split(sharedpath)[0]
-        srcurl, branches = parseurl(source)
-        srcrepo = repository(repo.ui, srcurl)
-    except IOError, inst:
-        if inst.errno != errno.ENOENT:
-            raise
-    return srcrepo
+    if repo.sharedpath == repo.path:
+        return None
+
+    # 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)
 
 def getbkfile(orig, self, repo):
     if _hassharedbookmarks(repo):
         srcrepo = _getsrcrepo(repo)
         if srcrepo is not None:
             repo = srcrepo
     return orig(self, 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 write(orig, self):
     # First write local bookmarks file in case we ever unshare
     orig(self)
     if _hassharedbookmarks(self._repo):
         srcrepo = _getsrcrepo(self._repo)
         if srcrepo is not None:
             self._writerepo(srcrepo)