IMAP: Retrieve on-disk folder state async.

* Messages that we don't have info for during synchronization are now
  collected, and synchronized once the folder state is available,
  instead of waiting for that particular entry to become available
  (without proper means to wait).

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

@@ -93,14 +93,21 @@ IMAPFolder::IMAPFolder(IMAPProtocol& protocol, const BString& mailboxName,
 	fMailboxName(mailboxName),
 	fUIDValidity(UINT32_MAX),
 	fLastUID(0),
-	fListener(NULL)
+	fListener(NULL),
+	fFolderStateInitialized(false),
+	fQuitFolderState(false)
 {
 	mutex_init(&fLock, "imap folder lock");
+	mutex_init(&fFolderStateLock, "imap folder state lock");
 }
 
 
 IMAPFolder::~IMAPFolder()
 {
+	if (!fFolderStateInitialized) {
+		fQuitFolderState = true;
+		wait_for_thread(fReadFolderStateThread, NULL);
+	}
 }
 
 
@@ -245,8 +252,10 @@ IMAPFolder::SyncMessageFlags(uint32 uid, uint32 mailboxFlags)
 		}
 		if (status == B_OK)
 			status = node.SetTo(&ref);
-		if (status == B_TIMED_OUT)
+		if (status == B_TIMED_OUT) {
-			continue;
+			// We don't know the message state yet
+			fPendingFlagsMap.insert(std::make_pair(uid, mailboxFlags));
+		}
 		if (status != B_OK)
 			return;
 
@@ -288,15 +297,32 @@ IMAPFolder::SyncMessageFlags(uint32 uid, uint32 mailboxFlags)
 void
 IMAPFolder::MessageEntriesFetched()
 {
-	// Delete all local messages that weren't synchronized with the server
+	_WaitForFolderState();
+
+	// Synchronize all pending flags first
+	UIDToFlagsMap::const_iterator pendingIterator = fPendingFlagsMap.begin();
+	for (; pendingIterator != fPendingFlagsMap.end(); pendingIterator++)
+		SyncMessageFlags(pendingIterator->first, pendingIterator->second);
+
+	fPendingFlagsMap.clear();
+
+	// Delete all local messages that are no longer found on the server
+
+	MutexLocker locker(fLock);
+	UIDSet deleteUIDs;
 	UIDToRefMap::const_iterator iterator = fRefMap.begin();
 	for (; iterator != fRefMap.end(); iterator++) {
 		uint32 uid = iterator->first;
 		if (fSynchronizedUIDsSet.find(uid) == fSynchronizedUIDsSet.end())
-			_DeleteLocalMessage(uid);
+			deleteUIDs.insert(uid);
 	}
 
 	fSynchronizedUIDsSet.clear();
+	locker.Unlock();
+
+	UIDSet::const_iterator deleteIterator = deleteUIDs.begin();
+	for (; deleteIterator != deleteUIDs.end(); deleteIterator++)
+		_DeleteLocalMessage(*deleteIterator);
 }
 
 
@@ -446,14 +472,42 @@ IMAPFolder::DeleteMessage(uint32 uid)
 void
 IMAPFolder::MessageReceived(BMessage* message)
 {
+	switch (message->what) {
+		default:
+			BHandler::MessageReceived(message);
+			break;
+	}
+}
+
+
+void
+IMAPFolder::_WaitForFolderState()
+{
+	while (true) {
+		MutexLocker locker(fFolderStateLock);
+		if (fFolderStateInitialized)
+			return;
+	}
 }
 
 
 void
 IMAPFolder::_InitializeFolderState()
 {
-	fInitializing = true;
+	mutex_lock(&fFolderStateLock);
 
+	fReadFolderStateThread = spawn_thread(&IMAPFolder::_ReadFolderState,
+		"IMAP folder state", B_NORMAL_PRIORITY, this);
+	if (fReadFolderStateThread >= 0)
+		resume_thread(fReadFolderStateThread);
+	else
+		mutex_unlock(&fFolderStateLock);
+}
+
+
+void
+IMAPFolder::_ReadFolderState()
+{
 	BDirectory directory(&fRef);
 	BEntry entry;
 	while (directory.GetNextEntry(&entry) == B_OK) {
@@ -472,6 +526,8 @@ IMAPFolder::_InitializeFolderState()
 		uint32 flags = _ReadFlags(node);
 
 		MutexLocker locker(fLock);
+		if (fQuitFolderState)
+			return;
 
 		fRefMap.insert(std::make_pair(uid, ref));
 		fFlagsMap.insert(std::make_pair(uid, flags));
@@ -497,7 +553,16 @@ IMAPFolder::_InitializeFolderState()
 //
 	}
 
-	fInitializing = false;
+	fFolderStateInitialized = true;
+	mutex_unlock(&fFolderStateLock);
+}
+
+
+/*static*/ status_t
+IMAPFolder::_ReadFolderState(void* self)
+{
+	((IMAPFolder*)self)->_ReadFolderState();
+	return B_OK;
 }
 
 
@@ -535,7 +600,7 @@ IMAPFolder::_GetMessageEntryRef(uint32 uid, entry_ref& ref) const
 {
 	UIDToRefMap::const_iterator found = fRefMap.find(uid);
 	if (found == fRefMap.end())
-		return fInitializing ? B_TIMED_OUT : B_ENTRY_NOT_FOUND;
+		return !fFolderStateInitialized ? B_TIMED_OUT : B_ENTRY_NOT_FOUND;
 
 	ref = found->second;
 	return B_OK;

src/add-ons/mail_daemon/inbound_protocols/imap/IMAPFolder.h

@@ -98,7 +98,11 @@ public:
 	virtual void				MessageReceived(BMessage* message);
 
 private:
+			void				_WaitForFolderState();
 			void				_InitializeFolderState();
+			void				_ReadFolderState();
+	static	status_t			_ReadFolderState(void* self);
+
 			const MessageToken	_Token(uint32 uid) const;
 			void				_NotifyStoredBody(const entry_ref& ref,
 									uint32 uid, status_t status);
@@ -150,10 +154,14 @@ private:
 			uint32				fLastUID;
 			FolderListener*		fListener;
 			mutex				fLock;
-			bool				fInitializing;
+			mutex				fFolderStateLock;
+			thread_id			fReadFolderStateThread;
+			bool				fFolderStateInitialized;
+			bool				fQuitFolderState;
 			UIDToRefMap			fRefMap;
 			UIDToFlagsMap		fFlagsMap;
 			UIDSet				fSynchronizedUIDsSet;
+			UIDToFlagsMap		fPendingFlagsMap;
 			MessengerMap		fPendingBodies;
 };