diff --git a/mozilla/mailnews/imap/src/nsImapMoveCoalescer.cpp b/mozilla/mailnews/imap/src/nsImapMoveCoalescer.cpp
new file mode 100644
index 00000000000..dd01a555bca
--- /dev/null
+++ b/mozilla/mailnews/imap/src/nsImapMoveCoalescer.cpp
@@ -0,0 +1,110 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * The contents of this file are subject to the Netscape Public License
+ * Version 1.0 (the "NPL"); you may not use this file except in
+ * compliance with the NPL.  You may obtain a copy of the NPL at
+ * http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the NPL is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
+ * for the specific language governing rights and limitations under the
+ * NPL.
+ *
+ * The Initial Developer of this code under the NPL is Netscape
+ * Communications Corporation.  Portions created by Netscape are
+ * Copyright (C) 1999 Netscape Communications Corporation.  All Rights
+ * Reserved.
+ */
+
+#include "msgCore.h"
+#include "nsImapMoveCoalescer.h"
+#include "nsMsgKeySet.h"
+#include "nsImapService.h"
+
+static NS_DEFINE_CID(kCImapService, NS_IMAPSERVICE_CID);
+
+nsImapMoveCoalescer::nsImapMoveCoalescer(nsImapMailFolder *sourceFolder)
+{
+	m_sourceFolder = sourceFolder;
+	if (sourceFolder)
+		NS_ADDREF(sourceFolder);
+}
+
+nsImapMoveCoalescer::~nsImapMoveCoalescer()
+{
+	NS_IF_RELEASE(m_sourceFolder);
+	for (PRInt32 i = 0; i < m_sourceKeySets.Count(); i++)
+	{
+		nsMsgKeySet *keys = (nsMsgKeySet *) m_sourceKeySets.ElementAt(i);
+		delete keys;
+	}
+}
+
+nsresult nsImapMoveCoalescer::AddMove(nsIMsgFolder *folder, nsMsgKey key)
+{
+	if (!m_destFolders)
+        NS_NewISupportsArray(getter_AddRefs(m_destFolders));
+	if (m_destFolders)
+	{
+		PRInt32 folderIndex = m_destFolders->IndexOf(folder);
+		nsMsgKeySet *keysToAdd;
+		if (folderIndex >= 0)
+		{
+			keysToAdd = (nsMsgKeySet *) m_sourceKeySets.ElementAt(folderIndex);
+		}
+		else
+		{
+			m_destFolders->AppendElement(folder);
+			keysToAdd = nsMsgKeySet::Create();
+			if (!keysToAdd)
+				return NS_ERROR_OUT_OF_MEMORY;
+
+			m_sourceKeySets.AppendElement(keysToAdd);
+		}
+		if (keysToAdd)
+			keysToAdd->Add(key);
+		return NS_OK;
+	}
+	else
+		return NS_ERROR_OUT_OF_MEMORY;
+
+}
+
+nsresult nsImapMoveCoalescer::PlaybackMoves(nsIEventQueue *eventQueue)
+{
+	PRUint32 numFolders;
+	nsresult rv = NS_OK;
+
+	m_destFolders->Count(&numFolders);
+	for (PRUint32 i = 0; i < numFolders; i++)
+	{
+		nsCOMPtr <nsISupports> myISupports = getter_AddRefs(m_destFolders->ElementAt(i));
+		nsCOMPtr <nsIMsgFolder> destFolder(do_QueryInterface(myISupports));
+        NS_WITH_SERVICE(nsIImapService, imapService, kCImapService, &rv);
+        if (NS_SUCCEEDED(rv) && imapService)
+		{
+			nsMsgKeySet *keysToAdd = (nsMsgKeySet *) m_sourceKeySets.ElementAt(i);
+			if (keysToAdd)
+			{
+				char *messageIds = keysToAdd->Output();
+				if (messageIds)
+				{
+					nsCOMPtr <nsISupports> myISupports = do_QueryInterface((nsIMsgImapMailFolder *) m_sourceFolder, &rv);
+					nsCOMPtr <nsIUrlListener> urlListener(do_QueryInterface(myISupports));
+					rv = imapService->OnlineMessageCopy(eventQueue,
+													m_sourceFolder, messageIds,
+													destFolder, PR_TRUE, PR_TRUE,
+													urlListener, nsnull);
+					delete [] messageIds;
+				}
+				else
+				{
+					rv = NS_ERROR_OUT_OF_MEMORY;
+					break;
+				}
+			}
+		}
+	}
+	return rv;
+}
+
diff --git a/mozilla/mailnews/imap/src/nsImapMoveCoalescer.h b/mozilla/mailnews/imap/src/nsImapMoveCoalescer.h
new file mode 100644
index 00000000000..f74308bdf5e
--- /dev/null
+++ b/mozilla/mailnews/imap/src/nsImapMoveCoalescer.h
@@ -0,0 +1,51 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * The contents of this file are subject to the Netscape Public License
+ * Version 1.0 (the "NPL"); you may not use this file except in
+ * compliance with the NPL.  You may obtain a copy of the NPL at
+ * http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the NPL is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
+ * for the specific language governing rights and limitations under the
+ * NPL.
+ *
+ * The Initial Developer of this code under the NPL is Netscape
+ * Communications Corporation.  Portions created by Netscape are
+ * Copyright (C) 1998, 1999 Netscape Communications Corporation.  All Rights
+ * Reserved.
+ */
+
+#ifndef _nsImapMoveCoalescer_H
+#define _nsImapMoveCoalescer_H
+
+#include "msgCore.h"
+#include "nsImapMailFolder.h"
+#include "nsISupportsArray.h"
+#include "nsCOMPtr.h"
+
+// imap move coalescer class - in order to keep nsImapMailFolder from growing like Topsy
+// Logically, we want to keep track of an nsMsgKeyArray per nsIMsgFolder, and then
+// be able to retrieve them one by one and play back the moves.
+// This utility class will be used by both the filter code and the offline playback code,
+// to avoid multiple moves to the same folder.
+
+#include "nsISupportsArray.h"
+
+class nsImapMoveCoalescer : public nsISupportsArray
+{
+public:
+	nsImapMoveCoalescer(nsImapMailFolder *sourceFolder);
+	virtual ~nsImapMoveCoalescer();
+
+	nsresult AddMove(nsIMsgFolder *folder, nsMsgKey key);
+	nsresult PlaybackMoves(nsIEventQueue *eventQueue);
+protected:
+	// m_sourceKeySets and m_destFolders are parallel arrays.
+	nsVoidArray					m_sourceKeySets;
+	nsCOMPtr <nsISupportsArray> m_destFolders;
+	nsImapMailFolder			*m_sourceFolder;
+};
+
+#endif // _nsImapMoveCoalescer_H
+