use random seeds for murmurhash2 change the three hardcoded seeds to fresh ones generated on demand via arc4random. Suggested/fixed by and ok stsp@

include header

shrink struct got_pack_meta a bit by removing the have_reused_delta flag This flag can be expressed as m->reused_delta_offset != 0 because all deltas in valid pack files will be written at a non-zero offset. We allocate a huge number of these structs during packing, so every little bit helps.

reduce the amount of memory used for caching deltas during deltification With files sorted properly for deltification we produce better deltas but end up consuming more memory and risk running into OpenBSD ulimits during packing. To compensate, reduce the threshold for the amount of delta data we store in memory, spooling more deltas into the cache file. ok op@

store a path hash instead of a verbatim path in pack meta data This reduces memory use by gotadmin pack. The goal is to sort files which share a path next to each other for deltification. A hash of the path is good enough for this purpose and consumes less memory than a verbatim copy of the path. Git does something similar. ok op@

fix paths stored in pack meta data, improving file deltification The old code was broken and stored an empty path or filenames, instead of a repository-relative path. Which means we didn't sort files for deltification as was intended. Fixing this provides much better deltas in large pack files written by gotadmin pack -a. In my test case, pack size changed from 2GB to 1.5GB. ok op@

plug a small memleak on error in got_pack_create()

avoid malloc/free for duplicate check in got_pathlists_insert() ok op@

revert "Skip poll(2) if an imsgbuf has a non-empty read buffer" imsg_read() will call recvmsg() on the file descriptor regardless of the read buffer's state, so we should ensure that data is ready. The read buffer is used by imsg_get(), not imsg_read(). We already call imsg_get() before imsg_read(), and call the latter only if imsg_get() returns zero.

Skip poll(2) if an imsgbuf has a non-empty read buffer.

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

batch up tree entries in imsg instead of sending one imsg per tree entry This speeds up loading of trees significantly. ok op@

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

prevent an out-of-bounds access in got_privsep_recv_tree()

plug memory leak in an error path of got_privsep_recv_tree()