store deltas in compressed form while packing, both in memory and cache file This reduces memory and disk space consumption during packing. with tweaks + memleak on error fix from op@ ok op@

avoid subtraction of values larger than int in qsort(3) comparison callbacks tweak + ok tb@

inline struct got_object_id in struct got_object_qid Saves us from doing a malloc/free call for every item on the list. ok op@

reimplement object-ID set data structure on top of a hash table Siphash suggested by jrick as a better alternative to murmurhash for this use case. with small fixes from and ok op@

speed up initial stage of packing by adding a "skip" commit color The skip color marks boundary commits and their ancestors. Boundary commits are reachable both via references which we want to exclude from the pack, and via references which we want to include in the pack. We continue processing commit history up to the point we are left with only skip commits on the queue. This can speed up findtwixt() significantly and avoids wrong results produced by the old algorithm which made no distinction between "drop" and "skip". This idea was first implemented by Michael Forney for git9: https://git.9front.org/plan9front/plan9front/2e47badb88312c5c045a8042dc2ef80148e5ab47/commit.html Michael's log message for git9 is reproduced below: git/query: refactor graph painting algorithm (findtwixt, lca) We now keep track of 3 sets during traversal: - keep: commits we've reached from head commits - drop: commits we've reached from tail commits - skip: ancestors of commits in both 'keep' and 'drop' Commits in 'keep' and/or 'drop' may be added later to the 'skip' set if we discover later that they are part of a common subgraph of the head and tail commits. From these sets we can calculate the commits we are interested in: lca commits are those in 'keep' and 'drop', but not in 'skip'. findtwixt commits are those in 'keep', but not in 'drop' or 'skip'. The "LCA" commit returned is a common ancestor such that there are no other common ancestors that can reach that commit. Although there can be multiple commits that meet this criteria, where one is technically lower on the commit-graph than the other, these cases only happen in complex merge arrangements and any choice is likely a decent merge base. Repainting is now done in paint() directly. When we find a boundary commit, we switch our paint color to 'skip'. 'skip' painting does not stop when it hits another color; we continue until we are left with only 'skip' commits on the queue. This fixes several mishandled cases in the current algorithm: 1. If we hit the common subgraph from tail commits first (if the tail commit was newer than the head commit), we ended up traversing the entire commit graph. This is because we couldn't distinguish between 'drop' commits that were part of the common subgraph, and those that were still looking for it. 2. If we traversed through an initial part of the common subgraph from head commits before reaching it from tail commits, these commits were returned from findtwixt even though they were also reachable from tail commits. 3. In the same case as 2, we might end up choosing an incorrect commit as the LCA, which is an ancestor of the real LCA.

make sure callers of got_object_idset_add() free data.

revert 03c03172 "drop a commit right away if it matches an excluded commit" This change resulted in a full history walk even when no objects will be added to the pack file. Fix this regression by reverting the change.

for clarity, move the coloring loop from findtwixt() into a separate function

remove a pointless object-id dup/free dance in findtwixt()

don't forget to call the cancel callback while coloring commits in findtwixt()

in findtwixt(), drop a commit right away if it matches an excluded commit

the obj_types array in pack_create.c is no longer useful, remove it

make gotadmin pack -x option work with tag arguments

in load_object_ids(), process "their" commits and tags in the same loop No functional change, the end result is the same.

fix pack progress object counter for loose objects Move pack progres object accounting to a single place. This makes it easier to account for the case were only loose objects are packed. A wrong amount of objects was reported before when packing loose ones.

in pack progress output, remove excluded objects from 'found' objects counter

fix a bug where 'gotadmin pack' packed too many objects unless -a was used

explicitly include <unistd.h> for close(2)

print additional progress information while packing ok op@

cache a list of known pack index files when the repository is opened Avoids overhead due to readdir calls while searching a pack index. ok op@

portable: pack-create: remove endian.h endian.h is portably included on non-OpenBSD systems, so let that mechanism determine if it should be included or not.

explicitly include <endian.h> for be32toh()

fix pack.sh test failure from reuse-deltas patch by tweaking progress output

reuse existing deltas when creating pack files tested by thomas, naddy, and myself

compress delta data from delta_cache directly into pack file