Retrieving all possible join trees from PLANNER..

Hello all,

I am using Postgres to do my Masters' thesis work. Given a query, i want 
to know all possible join plan trees for that query.

This information can be got from 
src/backend/optimizer/path/allpaths.c/make_one_rel_by_joins() method.
[ie] more specifically, I need joinitems[levels_needed]

The information i need is a temporary result generated by planner and is 
not passed on to later stages. Hence If i add a command, i wont have 
this infomation by the time ProcessUtility() method is called.

How do i efficiently retrieve this information?

The input to my method is a file containing queries, and output should 
be all possible join plan trees for each query in the file...

Thanks in advance,
Gayathri TK