[Apso-devel] Logging system and defensive code (for Apso 0.3.0)

[Jeronimo Pellegrini]

Caio has been working on the missing items for release 0.2.0 (fixing
types and using bdata instead of char*).

I'll start working on the stuff for 0.3.0. Basically, we need:

- Robustness. We need to detect more problematic situations, handle
  errors more graciously whenever possible, and be more consistent
  with our dealing with exceptions. So, I thought we could have
  something like:
  + Sanity checks inside the code (a la Monotone)
  + Review the use of exception throwing, and maybe start catching
    more of them
  + Isolate the filesystem handling code and make it more robust.
    Maybe something like a FileSystem class, or a namespace
    apso::filesystem. This part of the code should:
    . Automaticaly create of entire paths if necessary
    . Give the caller some feedback (permission denied, file found
      where a directory was expected, etc)
    . Rollback partially done operations if it can't be done entirely
      (if we created a/b/c/, but couldn't write to a/b/c/d, then
       delete a, b and c)
    I'd like to be able to do this:
    FileSystem::file_exists(path_list);
    And that function will take care of all that is needed. Maybe we
    could pass the required permissions for the paths and files in the
    path_list also.


- Start using a logging mechanism instead of writing to stdout. I
  though of making it pluggable through an abstract class, pretty much
  as Cryptengine and VersionControl. That would be the "Logger" class.
  As a first attemt to implement a logger, we could use a very simple
  logging system, like slogcxx:
  http://vislab-ccom.unh.edu/~schwehr/software/slogcxx/
  The reason for choosing it is the same behind the coice of Nettle:
  simplicity and ease of use.

Any comments on these?


For 0.3.0, we will also need:

- A test framework. Caio is also working on that. BTW, Caio, could you
  say more about your ideas for tests?

J.