imsg_add() frees its msg argument on error; avoid double-free in error paths

parse tree entries into an array instead of a pathlist Avoids some extra malloc/free in a performance-critical path. ok op@

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@

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

avoid the creation of new temporary files whenever a packed object is read This speeds up the creation of pack files by about 30%.

wrap overlong lines

fix some integers that had a slightly wrong type; patch by Omar Polo

add 'static' qualifier to local functions in got-read-pack; patch by Omar Polo

don't scan pack index offsets for large values if pack file is < 2GB This saves an iteration over the entire h->offsets array when opening a pack index which should not contain large offsets in the first place. ok millert@

switch from SIMPLEQ to equivalent STAILQ macros The singly-linked tail queue macros were added to OpenBSD 6.9 and are more widely available on other systems. ok stsp

fix raw object size sent by got-read-pack

implement raw object data access; this will be required for packing

make close(2) failure checks consistent; check 'close() == -1' everywhere ok millert, naddy

make fclose(3) failure checks consistent; check 'fclose() == EOF' everywhere ok millert, naddy

indentation fixes

Stop including <sys/syslimits.h> directly. POSIX says the limits defined there are available from <limits.h>, which almost all affected source files already included anyway. ok millert stsp

do not rely on <zlib.h> to pull in <unistd.h> ok stsp

remove got_packidx_get_object_idx_sha1(); it is not actually needed

include the relevant object ID in NO_OBJ error messages where possible

move functions from privsep.c to the helpers which use them where possible

remove GOT_ERR_NOT_ABSPATH and fix existing users to deal with absolute paths

when "bad path" errors occur, always show the path in question

add support for first-parent history traversal to got-read-pack