Libsvn within Geometry Database Format

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BRL-CAD's new Geometry Service is intended to provide modeling software with the ability to act as a "client" that can request models and versions of models from a repository, much like BRL-CAD's source code is stored in a repository and developers can request specific subsets and revisions. This Geometry Service will be utilizing the subversion libraries for version control "under the hood".

While geometry databases are currently stored as files, the goal for geometry service is to allow individual regions to be revision controlled instead of just .g files. This raises the question of how to handle the geometry data for a server on the backend - lots of tiny .g files, one per region?

An interesting possibility is to make use of the ability of the subversion libraries to communicate to different backend systems to store revision information. The current default backend (FSFS) is filesystem based, but there is an older backend based on BerkeleyDB. This project would investigate the possibility of porting the FSFS filesystem based subversion backend logic to communicate directly with the .g database format, storing geometry revisions and geometry information without needing to interact with regular files. Because the Geometry Service is a special case (it does not need to revision control arbitrary file types) a geometry specific backend may be able to improve on performance characteristics of a basic subversion approach.

The other piece of the puzzle required for subversion-in-.g-files is the ability to check out a revision of a repository to a .g file, instead of individual files on a filesystem. This may be more challenging - it is not currently known how deep the assumptions of "checkout writes to filesystem" are embedded in the subversion libraries.

The task is to both commit into and checkout into .g file based subversion repositories.


  • geomcore module
    • separate from the 'brlcad' checkout, containing the geometry service


  • Familiarity with C
  • (optional) Knowledge of Apache Portable Runtime and Subversion libraries