how to migrate from old php database handler library to pdo without older codes break?

I used AdoDb database handler library for my project, now I want to migrate to PDO but I don't want that whole project stop working what can I do?

I used about 10 methods of that handler(and use simple query that work pdo too) so I found two solution for this:

1- extends pdo class and add adodb methods signature to it and fix it to work with PDO

2- wrap pdo class and add those methods...

what do you suggest and what should i consider about it?