krh@1: - keep history of installed packages/journal of package transaction,
krh@1:   so we can roll back to yesterday, or see what got installed in the
krh@1:   latest yum update.
krh@1: 
krh@1: - we build a cache of the currently installed set to service
krh@1:   dependency inquiries fast:
krh@1: 
krh@1: 	map from property to pkg (as hash) providing it
krh@1: 	map from property to pkgs requiring it
krh@1: 	map from pkg name to manifest
krh@1: 	map from string to string pool index
krh@1: 
krh@1: 	no implicit provides? not even pkgname?
krh@1: 
krh@1: - properties are strings, stored in a string table
krh@1: 
krh@1: - on disk maps are binary files of (string table index, hash) pairs
krh@1: 
krh@1: - at run time, we mmap the map, and keep changes in memory in a splay
krh@1:   tree or similar.  if searching the splay tree fails we punt to the
krh@1:   mmap.  once the transaction is done, we merge the map and the splay
krh@1:   tree and write it back out.
krh@1: 
krh@1: - the on-disk string pool is sorted and we keep a list of indices into
krh@1:   the string pool in sorted order so we can bsearch the list with a
krh@1:   string to get its string pool index.  maybe a hash table is better,
krh@1:   less I/O as we will expect to find the string within the block we
krh@1:   look up with the hash function.
krh@1: 
krh@5: - represent all files as a breadth first traversal of the tree of all
krh@5:   files.  each entry has its name (string pool index), the number of
krh@5:   immediate children, total number of children, and owning package.
krh@5:   for files both these numbers are zero.  a file is identified by its
krh@5:   index in this flattened tree.
krh@5: 
krh@5:   to get the file name from an index, we search through the list.  by
krh@5:   summing up the number of children, we know when to skip a directory
krh@5:   and when to descend into one.  as we go we accumulate the path
krh@5:   elements.
krh@5: 
krh@5:   hmm, dropping number of immediate children and using a sentinel drops
krh@5:   a word from every entry.
krh@5: 
krh@1: - signed pkgs
krh@8: 
krh@8: - gzip repository of look-aside pkg xml files somehow?
krh@8: 
krh@8: - transactions, proper recovery, make sure we don't poop our package
krh@8:   database (no more rm /var/lib/rpm/__cache*).
krh@8: 
krh@8: - no external dependencies, forget about bdb, sqlite.  It's *simple*
krh@8:   and we need to control the on-disk format for these tools.
krh@8: 
krh@18: - diff from one package set to another answers: "what changed in
krh@18:   rawhide between since yesterday?"
krh@18: 
krh@18: - rewrite qsort and bsearch that doesn't require global context var
krh@18:   and can output a map describing the permutaion.
krh@18: 
krh@18: - use hash table for package and property lists so we only store
krh@18:   unique lists (like for string pool).
krh@40: 
krh@40: - use existing, running system as repo; eg
krh@40: 
krh@40: 	razor update razor://other-box.local evince
krh@40: 
krh@40:   to pull eg the latest evince and dependencies from another box.  We
krh@40:   should be able to regenerate a rzr pkg from the system so we can
krh@40:   reuse the signature from the originating repo.
krh@41: 
krh@41: - Ok, maybe the fastest package set merge method in the end is to use
krh@41:   the razor_importer, but use a hash table for the properties.  This
krh@41:   way we can assign them unique IDs immediately (like tokenizing
krh@41:   strings).