move got_opentempfd() out of lib/diff.c again ok tracey

pass the correct file to fdopen(); ok tracey

fix missed dup in open_blob per stsp@

move got_opentempfd out of open_blob. ok stsp@

allow start_pack_privsep_child() to be called from outside lib/object.c

build with -Wmissing-prototypes ok stsp@

let got-read-pack be explicit about whether it could enumerate all objects This allows the main process to avoid looping over all object IDs again in case the pack file used for enumeration is complete. ok op@

Bring back object enumeration inside got-read-pack as a fast path. The problem that was found in the earlier version has been fixed. ok op@

revert object enumeration in got-read-pack for now; needs more work This implementation marked commits and trees as enumerated before all trees which they depend on were enumerated. This behaviour leads to incomplete pack files when a tree is only partially packed and got-read-pack hits a missing tree entry as a result. The algorithm must be reworked such that packed leave nodes are marked enumerated first, then bubble-up. Found by op@

implement object enumeration support in got-read-pack ok op@

open temporary files needed for delta application in got_repo_open() This prepares for callers of got_repo_open() that cannot afford to open files in /tmp, such as gotwebd. In a follow-up change, we could ask such callers to pass in the required amount of open temporary files. One consequence is that got_repo_open() now requires the "cpath" pledge promise. Add the "cpath" promise to affected callers and remove it once the repository has been opened. ok tracey

run the search for deltas to reuse in got-read-pack This significantly speeds up the deltification step of packing by avoiding imsg traffic. gotadmin no longer requests individual raw deltas from got-read-pack to check whether it can reuse them. Instead, got-read-pack obtains a list of objects we want to pack, and hands back the list of all deltas in its pack file which can be reused. Messages are now batched such that imsg buffers are filled as much as possible. Another advantage is that deltas we are not going to reuse will no longer be written to the delta cache file, saving disk space. Before this patch, any raw delta candidate was written to the delta cache file by got-read-pack, and the decision whether to reuse the delta happened afterwards in the gotadmin process. Code for reading individual raw deltas is now unused and could be removed at some point. ok op@

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@

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@

stop relying on commit cache for good performance of got_object_id_by_path() Instead of internally opening and closing the same commit object over and over again, require callers to pass an open commit object in. Avoids an inherent dependency on the commit object cache for reasonable performance. ok op@