Check for cached hash entries to determine which (if any) hash types

Check for cached hash entries to determine which (if any) hash types
need to be generated for the current file.
In 1.0.9, each hash type was handled by a separate method, each of
which checked the cache. It looks like when these code paths were
unified (in a311fb96b84757ef8628e6a754232614a53b7891) the cache
checks were not incorporated into the new method.