We provide a novel trace semantics for positive core XPath that exposes all intermediate nodes visited by the query engine. This enables a detailed analysis of all information relevant to the query. We give two examples of such analyses in the form of access control policies. We translate positive core XPath into Linear Temporal Logic, showing that branching structures can be linearised effectively. The translation is proved correct. We use the SPIN model checker in a proof of concept implementation to resolve the queries, and to perform the access control. The performance of the implementation is shown to be competitive.
|CTIT Technical Report Series
|University of Twente, Centre for Telematics and Information Technology (CTIT)