Prevent from renaming 'INBOX' folder in IMAP (illegal_operation exception).

src/exception.hpp

@@ -415,6 +415,22 @@ public:
 };
 
 
+/** Illegal operation: cannot run this operation on the object.
+  */
+
+class illegal_operation : public messaging_exception
+{
+public:
+
+	illegal_operation(const string& msg = "")
+		: messaging_exception(msg.empty()
+			? "Illegal operation."
+			: "Illegal operation: " + msg + "."
+		  ) {}
+	~illegal_operation() throw() {}
+};
+
+
 /** Command error: operation failed (this is specific to the underlying protocol).
   */
 

src/messaging/IMAPFolder.cpp

@@ -1228,6 +1228,8 @@ void IMAPFolder::rename(const folder::path& newPath)
 		throw exceptions::illegal_state("Store disconnected");
 	else if (isOpen())
 		throw exceptions::illegal_state("Folder open");
+	else if (m_path.getSize() == 1 && m_name.getBuffer() == "INBOX")
+		throw exceptions::illegal_operation("Cannot rename 'INBOX' folder");
 
 	// Build the request text
 	std::ostringstream command;