GuessWithCache returns b.Guess(), but re-uses a cached return value if possible.

HasLockfileChanged returns false if the lockfile exists and has not changed since the last time UpdateFileHashes was called, or if it doesn't exist and it didn't exist last time either.

HasSpecfileChanged returns false if the specfile exists and has not changed since the last time UpdateFileHashes was called, or if it doesn't exist and it didn't exist last time either.

UpdateFileHashes caches the current states of the specfile and lockfile.

Write writes the current contents of the store from memory back to disk.