manifest cache

Here's a possible structure:

  user_home/.tap/
    cache
      gems/gem-name-version.rb
      user-env-index.rb

    cache.rb
    tap.yml

The tap.yml file is the global config file. Loading cache.rb will add Env.instances mapping original paths to cache files.

If a cache file is older than original/tap.yml, the cache is automatically removed or recreated. (hence tapping tap.yml is an easy way to recreate a cache)

Cache files should instantiate the Env. This makes dump/load pretty easy... just make some valid ruby dump, basically by inspecting the relevant hashes. Gems should still be activated from the cache, to ensure that nothing goes screwy. Adding a

  gem 'gem-name'

To the cache file should be sufficient.

To regenerate a manifest, use something like the manifest command which already loads all gems. Delete files beforehand.

When caching:

• load cache before adding anything to Env.instances
• mark any new instances
• at exit, resolve the full manifests for each instance and generate cache files
• at exit, regenerate/append instances.rb

Note the at_exit activities should only happen when exiting normally!