Programmatic access to the Photos Library on Mac OS X: PhotoKit / Photos Framework for Mac

In Objective-C, there's a Photos Framework a.k.a. PhotoKit which enables iOS developers to access the photos library on iPhone and iPad and to retrieve the pictures/videos along with their metadata.

How would Mac developers perform a similar task? It seems PhotoKit is only available in iOS 8.0. Is there an equivalent of the Photos Framework for Mac OS X?