Catch SystemExit and KeyboardInterrupt exceptions

Previously we did not catch KeyboardInterrupts explicitly as all of the
code was executed in forked child threads which would never receive
Ctrl-c exceptions. With the upcoming single threaded modus, this code
can be run in the main thread however, so we need to take care of
KeyboardInterrupts explicitly. As this is pretty highlevel code, we also
protect against receiving a SystemExit exception which is raised e.g. in
the ui.terminate() code by calling sys.exit().

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap/accounts.py

@@ -187,6 +187,8 @@ class AccountSynchronizationMixin:
             try:
                 try:
                     self.sync(siglistener)
+                except (KeyboardInterrupt, SystemExit):
+                    raise
                 except:
                     self.ui.warn("Error occured attempting to sync account " + self.name \
                                  + ": " + str(sys.exc_info()[1]))
@@ -201,6 +203,8 @@ class AccountSynchronizationMixin:
             try:
                 try:
                     self.sync(siglistener)
+                except (KeyboardInterrupt, SystemExit):
+                    raise
                 except:
                     self.ui.warn("Error occured attempting to sync account " + self.name \
                                  + ": " + str(sys.exc_info()[1]))
@@ -370,6 +374,8 @@ def syncfolder(accountname, remoterepos, remotefolder, localrepos,
         localfolder.syncmessagesto(statusfolder)
         statusfolder.save()
         localrepos.restore_atime()
+    except (KeyboardInterrupt, SystemExit):
+        raise
     except:
         ui.warn("ERROR in syncfolder for %s folder %s: %s" % \
                 (accountname,remotefolder.getvisiblename(),sys.exc_info()[1]))

offlineimap/init.py

@@ -334,14 +334,14 @@ class OfflineImap:
                                            'siglisteners': siglisteners})
             t.setDaemon(1)
             t.start()
-        except:
-            ui.mainException()
-    
-        try:
             threadutil.exitnotifymonitorloop(threadutil.threadexited)
-        except SystemExit:
+
+        except KeyboardInterrupt:
+            ui.terminate(1, errormsg = 'CTRL-C pressed, aborting...')
+            return
+        except (SystemExit):
             raise
         except:
-            ui.mainException()  # Also expected to terminate.
+            ui.mainException()