diff between current changelog and hibernate entities

is it possible to generate a diff changelog between the current changelog xml file and my hibernate/jpa entities without first applying the current changelog to a db and diffing that db with liquibase-hibernate?

as liquibase supports URLs of the type hibernate:spring:com.mycompany.model, could it support something like changelog:classpath:com/mycompany/model/changelog.xml.

I don't know how liquibase works but I suppose it constructs a relational model of its own either based on jdbc metadata or hibernate mappings... so I guess, it could do the same based on changelog files.

Thanks,

Xavier