added readonly attribute nsIMsgDatabase msgDatabase for undo work

mailnews/base/public/nsIMsgFolder.idl

@@ -26,10 +26,12 @@
 #include "nsISupportsArray.h"
 #include "nsIMessage.h"
 #include "nsITransactionManager.h"
+#include "nsIMsgDatabase.h"
 %}
 interface nsISupportsArray;
 interface nsIMessage;
 interface nsITransactionManager;
+interface nsIMsgDatabase;
 
 [scriptable, uuid(85e39ff0-b248-11d2-b7ef-00805f05ffa5)]
 interface nsIMsgFolder : nsIFolder {
@@ -132,6 +134,7 @@ interface nsIMsgFolder : nsIFolder {
 
 	readonly attribute wstring NewMessagesNotificationDescription;
 	readonly attribute nsIMsgFolder RootFolder;
+  readonly attribute nsIMsgDatabase msgDatabase;
 };
 
 

mailnews/base/util/nsMsgDBFolder.cpp

@@ -222,6 +222,16 @@ nsresult nsMsgDBFolder::SendFlagNotifications(nsISupports *item, PRUint32 oldFla
 	return rv;
 }
 
+NS_IMETHODIMP
+nsMsgDBFolder::GetMsgDatabase(nsIMsgDatabase** aMsgDatabase)
+{
+    if (!aMsgDatabase || !mDatabase)
+        return NS_ERROR_NULL_POINTER;
+    *aMsgDatabase = mDatabase;
+    NS_ADDREF(*aMsgDatabase);
+    return NS_OK;
+}
+
 NS_IMETHODIMP nsMsgDBFolder::OnKeyChange(nsMsgKey aKeyChanged, PRUint32 aOldFlags, PRUint32 aNewFlags, 
                          nsIDBChangeListener * aInstigator)
 {

mailnews/base/util/nsMsgDBFolder.h

@@ -44,6 +44,8 @@ public:
 	NS_IMETHOD GetCharset(PRUnichar * *aCharset);
 	NS_IMETHOD SetCharset(PRUnichar * aCharset);
 
+  NS_IMETHOD GetMsgDatabase(nsIMsgDatabase** aMsgDatabase);
+
 	//nsIDBChangeListener
 	NS_IMETHOD OnKeyChange(nsMsgKey aKeyChanged, PRUint32 aOldFlags, PRUint32 aNewFlags, 
                          nsIDBChangeListener * aInstigator);

mailnews/base/util/nsMsgFolder.cpp

@@ -1366,6 +1366,12 @@ NS_IMETHODIMP nsMsgFolder::GetRootFolder(nsIMsgFolder * *aRootFolder)
 	return aRoot->QueryInterface(nsIMsgFolder::GetIID(), (void**)aRootFolder);
 }
 
+NS_IMETHODIMP
+nsMsgFolder::GetMsgDatabase(nsIMsgDatabase** aMsgDatabase)
+{
+    return NS_ERROR_NOT_IMPLEMENTED;
+}
+
 nsresult nsMsgFolder::NotifyPropertyChanged(char *property, char *oldValue, char* newValue)
 {
 	nsCOMPtr<nsISupports> supports;

mailnews/base/util/nsMsgFolder.h

@@ -274,6 +274,7 @@ public:
 	NS_IMETHOD GetNewMessagesNotificationDescription(PRUnichar * *adescription);
 
 	NS_IMETHOD GetRootFolder(nsIMsgFolder * *aRootFolder);
+  NS_IMETHOD GetMsgDatabase(nsIMsgDatabase** aMsgDatabase);
 
 protected:
 	nsresult NotifyPropertyChanged(char *property, char* oldValue, char* newValue);