work for filter after the fact, r=naving, sr=sspitzer 11033

mailnews/base/public/nsIMsgFolder.idl

@@ -369,6 +369,7 @@ const nsMsgBiffState nsMsgBiffState_Unknown = 2; // We dunno whether there is ne
   void markAllMessagesRead();
   void markMessagesFlagged(in nsISupportsArray messages, in boolean markFlagged);
   void markThreadRead(in nsIMsgThread thread);
+  void setLabelForMessages(in nsISupportsArray messages, in nsMsgLabelValue label);
   nsIMsgDatabase getMsgDatabase(in nsIMsgWindow msgWindow);
   void setMsgDatabase (in nsIMsgDatabase msgDatabase);
   nsIMsgDatabase getDBFolderInfoAndDB(out nsIDBFolderInfo folderInfo);

mailnews/base/util/nsMsgFolder.cpp

@@ -2221,6 +2221,25 @@ nsMsgFolder::MarkMessagesFlagged(nsISupportsArray *messages, PRBool markFlagged)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsMsgFolder::SetLabelForMessages(nsISupportsArray *aMessages, nsMsgLabelValue aLabel)
+{
+  PRUint32 count;
+  NS_ENSURE_ARG(aMessages);
+  nsresult rv = aMessages->Count(&count);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  for(PRUint32 i = 0; i < count; i++)
+  {
+    nsCOMPtr<nsIMsgDBHdr> message = do_QueryElementAt(aMessages, i, &rv);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = message->SetLabel(aLabel);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsMsgFolder::AddMessageDispositionState(nsIMsgDBHdr *aMessage, nsMsgDispositionState aDispositionFlag)
 {

mailnews/base/util/nsMsgFolder.h

@@ -193,6 +193,7 @@ public:
   NS_IMETHOD MarkAllMessagesRead(void);
   NS_IMETHOD MarkMessagesFlagged(nsISupportsArray *messages, PRBool markFlagged);
   NS_IMETHOD MarkThreadRead(nsIMsgThread *thread);
+  NS_IMETHOD SetLabelForMessages(nsISupportsArray *messages, nsMsgLabelValue label);
 
   NS_IMETHOD GetChildWithURI(const char *uri, PRBool deep, PRBool caseInsensitive, nsIMsgFolder **_retval); 
   NS_IMETHOD EnableNotifications(PRInt32 notificationType, PRBool enable, PRBool dbBatching);

mailnews/imap/src/nsImapMailFolder.cpp

@@ -1627,6 +1627,19 @@ nsImapMailFolder::MarkMessagesRead(nsISupportsArray *messages, PRBool markRead)
   return rv;
 }
 
+NS_IMETHODIMP
+nsImapMailFolder::SetLabelForMessages(nsISupportsArray *aMessages, nsMsgLabelValue aLabel)
+{
+  PRUint32 count;
+  NS_ENSURE_ARG(aMessages);
+
+  nsCAutoString messageIds;
+  nsMsgKeyArray keysToLabel;
+  nsresult rv = BuildIdsAndKeyArray(aMessages, messageIds, keysToLabel);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return StoreImapFlags((aLabel << 9), PR_TRUE, keysToLabel.GetArray(), keysToLabel.GetSize());
+}
+
 NS_IMETHODIMP
 nsImapMailFolder::MarkAllMessagesRead(void)
 {

mailnews/imap/src/nsImapMailFolder.h

@@ -246,6 +246,7 @@ public:
 	NS_IMETHOD MarkAllMessagesRead(void);
 	NS_IMETHOD MarkMessagesFlagged(nsISupportsArray *messages, PRBool markFlagged);
   NS_IMETHOD MarkThreadRead(nsIMsgThread *thread);
+  NS_IMETHOD SetLabelForMessages(nsISupportsArray *aMessages, nsMsgLabelValue aLabel);
 
   NS_IMETHOD DeleteSubFolders(nsISupportsArray *folders, nsIMsgWindow *msgWindow);
 	NS_IMETHOD ReadFromFolderCacheElem(nsIMsgFolderCacheElement *element);