Kobj works by generating descriptions of methods. Each description holds a unique id as well as a default function. The description's address is used to uniquely identify the method within a class' method table.
A class is built by creating a method table associating one or more functions with method descriptions. Before use the class is compiled. The compilation allocates a cache and associates it with the class. A unique id is assigned to each method description within the method table of the class if not already done so by another referencing class compilation. For every method to be used a function is generated by script to qualify arguments and automatically reference the method description for a lookup. The generated function looks up the method by using the unique id associated with the method description as a hash into the cache associated with the object's class. If the method is not cached the generated function proceeds to use the class' table to find the method. If the method is found then the associated function within the class is used; otherwise, the default function associated with the method description is used.
These indirections can be visualized as the following:
object->cache<->class
All FreeBSD documents are available for download at http://ftp.FreeBSD.org/pub/FreeBSD/doc/
Questions that are not answered by the
documentation may be
sent to <freebsd-questions@FreeBSD.org>.
Send questions about this document to <freebsd-doc@FreeBSD.org>.