Remove a few loops in cgit for a large number of repos.

[john at keeping.me.uk (John Keeping)]

On Thu, Oct 10, 2013 at 10:44:55AM -0400, Michael Hess wrote:
> I am looking into using cgit for Drupal.org's repos, and wondering if we
> could remove code like this:
> http://git.zx2c4.com/cgit/tree/shared.c#n79
> 
> 
> We have almost 10,000 repos and are worried about the load from loops, and
> building the index it loops over. All of the repos are under a directory
> (in 2 different sub directories), so I was hoping we could just validate
> the directory path (making sure someone is not trying to do a ../../,etc)
> and allow it?
> 
> Could that be done?  Please let me know your thoughts.

Have you actually seen this causing excessive load, or is it only a
theoretical issue?

I expect it would be possible, in the case of scan-path, to load repos
from disk lazily, but that will probably add quite a lot of complexity
and I'm not convinced it's worthwhile.

That particular loop will only be executed once and I suspect it is
dwarfed by the time spent loading and parsing the config (cached project
list if you're using scan-path).