MiSFIT: A Tool for Constructing Safe Extensible C++ Systems

The boundary between application and system is becoming increasingly permeable. Extensible applications, such as web browsers, database systems, and operating systems, demonstrate the value of allowing end-users to extend and modify the behavior of what was formerly considered to be a static, inviolate system. Unfortunately, flexibility often comes with a cost: systems unprotected from misbehaved end-user extensions are fragile and prone to instability. Object-oriented programming models are a good fit for the development of this kind of system. An extension can be designed as a refinement to an existing class and loaded into a running system. In our model, when code is downloaded into the system, it is used to replace a virtual function on an existing C++ object. Because our tool is source-language neutral, it can be used to build safe, extensible systems written in other languages as well. There are three methods commonly used to make end-user extensions safe: restrict the extens...

• Type: Conference
• Year: 1997
• Where: COOTS
• Authors: Christopher Small
• Keywords: COOTS 1997, COOTS 2001, End-user Extensions, Extensible Systems, Safe Extensible Systems