Adapt plain status folder to gmail labels stuff

* Implements Status Folder format v2, with a mechanism to upgrade an
    old statusfolder.

  * Do not warn about Gmail and GmailMaildir needing sqlite backend
    anymore.

  * Clean repository.LocalStatus reusing some code from
    folder.LocalStatus.

  * Change field separator in the plaintext file from ':' to '|'. Now
    the local status stores gmail labels. If they contain field
    separator character (formerly ':'), they get messed up. The new
    character '|' is less likely to appear in a label.

Signed-off-by: Eygene Ryabinkin <rea@codelabs.ru>

offlineimap/repository/Gmail.py

@@ -36,12 +36,6 @@ class GmailRepository(IMAPRepository):
                                 'ssl', 'yes')
         IMAPRepository.__init__(self, reposname, account)
 
-        if self.account.getconfboolean('synclabels', 0) and \
-              self.account.getconf('status_backend', 'plain') != 'sqlite':
-            raise OfflineImapError("The Gmail repository needs the sqlite backend to sync labels.\n"
-                                   "To enable it add 'status_backend = sqlite' in the account section",
-                                   OfflineImapError.ERROR.REPO)
-
 
     def gethost(self):
         """Return the server name to connect to.

offlineimap/repository/GmailMaildir.py

@@ -25,12 +25,6 @@ class GmailMaildirRepository(MaildirRepository):
         """Initialize a MaildirRepository object.  Takes a path name
         to the directory holding all the Maildir directories."""
         super(GmailMaildirRepository, self).__init__(reposname, account)
-        if self.account.getconfboolean('synclabels', 0) and \
-              self.account.getconf('status_backend', 'plain') != 'sqlite':
-            raise OfflineImapError("The GmailMaildir repository needs the sqlite backend to sync labels.\n"
-                                   "To enable it add 'status_backend = sqlite' in the account section",
-                                   OfflineImapError.ERROR.REPO)
-
 
 
     def getfoldertype(self):

offlineimap/repository/LocalStatus.py

@@ -16,7 +16,7 @@
 #    along with this program; if not, write to the Free Software
 #    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 
-from offlineimap.folder.LocalStatus import LocalStatusFolder, magicline
+from offlineimap.folder.LocalStatus import LocalStatusFolder
 from offlineimap.folder.LocalStatusSQLite import LocalStatusSQLiteFolder
 from offlineimap.repository.Base import BaseRepository
 import os
@@ -49,19 +49,6 @@ class LocalStatusRepository(BaseRepository):
     def getsep(self):
         return '.'
 
-    def getfolderfilename(self, foldername):
-        """Return the full path of the status file
-
-        This mimics the path that Folder().getfolderbasename() would return"""
-        if not foldername:
-            basename = '.'
-        else: #avoid directory hierarchies and file names such as '/'
-            basename = foldername.replace('/', '.')
-        # replace with literal 'dot' if final path name is '.' as '.' is
-        # an invalid file name.
-        basename = re.sub('(^|\/)\.$','\\1dot', basename)
-        return os.path.join(self.root, basename)
-
     def makefolder(self, foldername):
         """Create a LocalStatus Folder
 
@@ -73,11 +60,10 @@ class LocalStatusRepository(BaseRepository):
         if self.account.dryrun:
             return # bail out in dry-run mode
 
-        filename = self.getfolderfilename(foldername)
-        file = open(filename + ".tmp", "wt")
-        file.write(magicline + '\n')
-        file.close()
-        os.rename(filename + ".tmp", filename)
+        # Create an empty StatusFolder
+        folder = self.LocalStatusFolderClass(foldername, self)
+        folder.save()
+
         # Invalidate the cache.
         self._folders = {}