Rather than always doing:
1) make temporary link
2) unlink() target
3) rename()
Just try making the link, and only do the second two if the file
already exists. This reduces system call traffic a lot.
By default, when doing a commit, scan all of our loose objects and
build up a (device,inode) -> checksum hash. Then when we're doing a
commit, if we see a file with that (device,inode) pair, we can avoid
checksumming it.
This will allow us to use hard links again for user-mode checkouts,
rather than the hackish link cache. It was pretty silly anyways to
have file objects be stored with just a small metadata header
prepended, but uncompressed.
Either they should be hardlinkable, or compressed (in pack files).
Rather than passing xattr/file_info for all objects, change the API to
assume we're passing the defined object stream for each type. Namely,
for OSTREE_OBJECT_TYPE_FILE, we're now giving the "archive file" data.
This significantly cleans up the code for committing to archive mode
repositories, at the cost of having to (at present) create an
intermediate temporary file when committing to raw repositories.
This will be useful for ostbuild; a user can create their own archive
mode repository which transparently inherits objects from the
root-owned one in /ostree.
This is a convenient way to have a lookaside directory of hard links,
which can greatly speed up checkouts. In the future we probably want
to push this down into the repository.
Having the archived vs not distinction in the object system wasn't
useful in light of pack files. In fact, we should probably move
towards generating a pack file per commit by default.
Don't expose GChecksum in APIs. Add a new stream class which allows
us to pass an input stream somewhere, but gather a checksum as it's
read.
Move some bits of the internals towards binary csums.
Previously we had the "staged" state to ensure we didn't add a commit
object without the associated dirtree, etc. However it's
easier/better to just ensure in the pull command that we have all
referenced objects.
Also change pull to download metadata first. This will allow adding
a progress bar later.
Colin Walters