ref: 183f3d40a1dbc2254f1e01de21eb022996f40ad2
dir: /lib/std/wait+plan9.myr/
use sys use "alloc" use "chartype" use "die" use "extremum" use "hashfuncs" use "hasprefix" use "htab" use "intparse" use "option" use "strsplit" use "striter" use "syswrap" use "utf" use "sleq" use "fmt" use "threadhooks" pkg std = type waitstatus = union `Wsuccess `Wfailure `Wsignalled `Waiterror ;; const wait : (pid : pid -> waitstatus) const waitany : (-> (pid, waitstatus)) ;; var statusmap : htab(pid, waitstatus)# const __init__ = { statusmap = mkht() } const waitany = { var buf : byte[512] var ret, it lock(envlck) if htcount(statusmap) == 0 unlock(envlck) match sys.await(buf[:]) | -1: -> (-1, `Waiterror) | n: -> parsestatus(buf[:n]) ;; else it = std.byhtkeyvals(statusmap) __iternext__(&it, &ret) unlock(envlck) -> ret ;; } const wait = {pid var buf : byte[512] var xpid, status lock(envlck) match htget(statusmap, pid) | `None: | `Some st: unlock(envlck) htdel(statusmap, pid) -> st ;; unlock(envlck) while true match sys.await(buf[:]) | -1: -> `Waiterror | n: (xpid, status) = parsestatus(buf[:n]) ;; if xpid == pid -> status else lock(envlck) htput(statusmap, xpid, status) unlock(envlck) ;; ;; /* impossible */ -> `Waiterror } const parsestatus = {status -> (pid, waitstatus) var st : waitstatus var spbuf : byte[:][5] var xpid, sp sp = bstrsplit(spbuf[:], status, " ") if sp.len == 0 -> (-1, `Wfailure) ;; match intparse(sp[0]) | `Some pid: xpid = pid /* exits(nil) => sp[0] either not present or equal to '' */ if sp.len == 4 || (sp.len == 5 && sleq(sp[4], "''")) st = `Wsuccess elif sp.len == 5 st = `Wfailure else /* we have a malformed await message */ st = `Waiterror ;; | `None: xpid = -1 st = `Waiterror ;; -> (xpid, st) }