Per-account locking

Previously, we were simply locking offlineimap whenever it was
running. Howver there is no reason why we shouldn't be able to invoke it
in parallel, e.g. to synchronize several accounts in one offlineimap
each.

This patch implements the locking per-account, so that it is possible to
sync different accounts at the same time. If in refresh mode, we will
attempt to loop three times before giving up.

This also fixes Debian bug #586655

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>

offlineimap/init.py

@@ -30,14 +30,6 @@ from offlineimap.ui import UI_LIST, setglobalui, getglobalui
 from offlineimap.CustomConfig import CustomConfigParser
 
 
-try:
-    import fcntl
-    hasfcntl = 1
-except:
-    hasfcntl = 0
-
-lockfd = None
-
 class OfflineImap:
     """The main class that encapsulates the high level use of OfflineImap.
 
@@ -46,17 +38,6 @@ class OfflineImap:
       oi = OfflineImap()
       oi.run()
     """
-    def lock(self, config, ui):
-        global lockfd, hasfcntl
-        if not hasfcntl:
-            return
-        lockfd = open(config.getmetadatadir() + "/lock", "w")
-        try:
-            fcntl.flock(lockfd, fcntl.LOCK_EX | fcntl.LOCK_NB)
-        except IOError:
-            ui.locked()
-            ui.terminate(1)
-    
     def run(self):
         """Parse the commandline and invoke everything"""
 
@@ -253,7 +234,6 @@ class OfflineImap:
                     config.set(section, "folderfilter", folderfilter)
                     config.set(section, "folderincludes", folderincludes)
 
-        self.lock(config, ui)
         self.config = config
     
         def sigterm_handler(signum, frame):