mail: IMAP inbound protocol destructor fix

This should fix crashes of mailer_daemon in IMAP workers.
This patch makes IMAPConnection destructor wait for all working threads to finish.
Also, do not call _Connect for QuitCommand (it speedups shutdown procedure).

Change-Id: Idffcc00d3459a96a85a8a073a343bcf4cd4984be
Reviewed-on: https://review.haiku-os.org/686
Reviewed-by: waddlesplash <[email protected]>

src/add-ons/mail_daemon/inbound_protocols/imap/IMAPConnectionWorker.cpp

@@ -618,6 +618,10 @@ void
 IMAPConnectionWorker::Quit()
 {
 	printf("IMAP: worker %p: enqueue quit\n", this);
+	BAutolock locker(fLocker);
+	while (!fPendingCommands.IsEmpty())
+		delete(fPendingCommands.RemoveItemAt(0));
+	locker.Unlock();
 	_EnqueueCommand(new QuitCommand());
 }
 
@@ -732,7 +736,11 @@ IMAPConnectionWorker::_Worker()
 
 		CommandDeleter deleter(*this, command);
 
-		status_t status = _Connect();
+		status_t status = B_OK;
+
+		if (dynamic_cast<QuitCommand*>(command) == NULL) // do not connect on QuitCommand
+			status = _Connect();
+
 		if (status != B_OK) {
 			fOwner.WorkerQuit(this);
 			return status;

src/add-ons/mail_daemon/inbound_protocols/imap/IMAPProtocol.cpp

@@ -38,6 +38,15 @@ IMAPProtocol::IMAPProtocol(const BMailAccountSettings& settings)
 
 IMAPProtocol::~IMAPProtocol()
 {
+	MutexLocker locker(fWorkerLock);
+	for (int32 i = 0; i < fWorkers.CountItems(); i++)
+		fWorkers.ItemAt(i)->Quit();
+	int tries = 10;
+	while (fWorkers.CountItems() > 0 && --tries > 0) {
+		locker.Unlock();
+		snooze(500000);
+		locker.Lock();
+	}
 }