urbit/pkg/arvo/sys/vane/khan.hoon
Jōshin 340f4d5b6c
khan: %fard/%arow use $cage, not $vase
Threads should eventually take and produce $cage instead of $vase. Since
%khan is likely to be used by third parties, we write to the eventual
intended API. We ignore the mark on the input $cage (it is safe to
always specify %noun), and we always use %noun as the output mark.

%fyrd now makes more sense. It was previously discarding the type of the
output %arow and re-encoding the raw noun as a vase of the output mark;
it is now performing mark conversion from the mark of the output $cage
to the originally requested output mark.
2022-03-02 13:07:52 -06:00

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:: %khan, thread runner
::
:: this vane presents a command/response interface for running
:: threads. two modes are supported: %fard for intra-arvo
:: requests (i.e. within the same kernel space) and %fyrd for
:: external requests (e.g. from the unix control plane.)
::
:: both modes take a thread start request consisting of a
:: namespace, thread name, and input data; they respond over the
:: same duct with either success or failure. %fard takes its
:: input arguments as a vase and produces %arow, which contains
:: a vase on success (or tang on failure). %fyrd takes an output
:: mark and input crag; it produces %avow, which contains a crag
:: on success.
::
:: %fard passes its arguments and produces its result
:: unmodified. %fyrd does mark conversion on both ends, and
:: additionally lifts its input into a $unit. this second step
:: is done because threads conventionally take their input as a
:: unit, with ~ for the case of "no arguments".
::
:: n.b. the current convention for threads is to use !< to
:: unpack their input into a well-defined type. !< imposes the
:: requirement that the input type nests within the specified
:: type. this limits %fyrd to threads with inputs for which a
:: named mark exists; it is impossible to use %noun in general
:: since it does not nest. to support using the %noun mark for
:: inputs, it would be sufficient to convert threads to use ;;
:: rather than !< on their inputs, at the cost of losing type
:: validation.
!:
!? 164
::
=, khan
|= our=ship
=> |% :: %khan types
+$ move [p=duct q=(wite note gift)] ::
+$ note :: out request $->
$~ [%g %deal *sock *term *deal:gall] ::
$% $: %g :: to %gall
$>(%deal task:gall) :: full transmission
== ::
$: %k :: to self
$>(%fard task) :: internal thread
== == ::
+$ sign :: in response $<-
$% $: %gall :: from %gall
$>(%unto gift:gall) :: update
== ::
$: %khan :: from self
$> ?(%arow %avow) gift :: thread result
== == ::
+$ khan-state ::
[%0 hey=duct] :: current unix duct
-- ::
=>
|%
++ get-beak
|= [=bear now=@da]
?@(bear [our bear %da now] bear)
++ get-dais
|= [=beak =mark rof=roof]
^- dais:clay
?~ ret=(rof ~ %cb beak /[mark])
~|(mark-unknown+mark !!)
?~ u.ret
~|(mark-invalid+mark !!)
?> =(%dais p.u.u.ret)
!<(dais:clay q.u.u.ret)
++ get-tube
|= [=beak =mark =out=mark rof=roof]
^- tube:clay
?~ ret=(rof ~ %cc beak /[mark]/[out-mark])
~|(tube-unknown+[mark out-mark] !!)
?~ u.ret
~|(tube-invalid+[mark out-mark] !!)
?> =(%tube p.u.u.ret)
!<(tube:clay q.u.u.ret)
++ make-wire
|= [=beak =mark]
^- wire
:~ %fyrd
(scot %p p.beak)
q.beak
-.r.beak
(scot r.beak)
mark
==
++ read-case
|= a=[p=@ @]
^- case
:: XX should be:
:: ?> ?=(?(%da %tas %ud) p.a)
:: [p.a (slav a)]
::
?+ p.a !!
%da [p.a (slav a)]
%tas [p.a (slav a)]
%ud [p.a (slav a)]
==
++ read-wire
|= =wire
^- (pair beak mark)
~| khan-read-wire+wire
?> ?=([%fyrd @ @ @ @ @ ~] wire)
:_ i.t.t.t.t.t.wire
:+ (slav %p i.t.wire)
i.t.t.wire
(read-case [i i.t]:t.t.t.wire)
++ start-spider
|= [our=@p =vase]
^- note
[%g %deal [our our] %spider %poke %spider-start vase]
++ watch-spider
|= [our=@p =path]
^- note
[%g %deal [our our] %spider %watch path]
--
=| khan-state
=* state -
|= [now=@da eny=@uvJ rof=roof]
=* khan-gate .
^?
|%
:: +call: handle a +task request
::
++ call
|= $: hen=duct
dud=(unit goof)
wrapped-task=(hobo task)
==
^- [(list move) _khan-gate]
::
=/ =task ((harden task) wrapped-task)
?^ dud
~|(%khan-call-dud (mean tang.u.dud))
?+ -.task [~ khan-gate]
%born
[~ khan-gate(hey hen)]
::
%fard
=/ tid=@ta
(cat 3 'khan-fyrd--' (scot %uv (sham eny)))
=* fyd p.task
=/ =beak (get-beak bear.fyd now)
=/ args [~ `tid beak name.fyd q.args.fyd]
:_ khan-gate
%+ turn
:~ (watch-spider our /thread-result/[tid])
(start-spider our !>(args))
==
|=(=note ^-(move [hen %pass //g note]))
::
%fyrd
=* fyd p.task
=/ =beak (get-beak bear.fyd now)
=/ =wire (make-wire beak p.args.fyd)
=/ =dais:clay
(get-dais beak p.q.args.fyd rof)
=/ =vase
(slap (vale.dais q.q.args.fyd) !,(*hoon [~ u=.]))
=- [[hen %pass wire -]~ khan-gate]
[%k %fard bear.fyd name.fyd p.q.args.fyd vase]
==
:: +load: migrate an old state to a new khan version
::
++ load
|= old=khan-state
^+ khan-gate
khan-gate(state old)
:: +scry: nothing to see as yet
::
++ scry
^- roon
|= [lyc=gang car=term bem=beam]
^- (unit (unit cage))
~
++ stay state
:: +take: handle responses.
::
++ take
|= [tea=wire hen=duct dud=(unit goof) hin=sign]
^- [(list move) _khan-gate]
?^ dud
~|(%khan-take-dud (mean tang.u.dud))
:_ khan-gate
?- -.hin
%gall
?+ -.p.hin ~
?(%poke-ack %watch-ack)
?~ p.p.hin ~
%- (slog 'khan-ack' u.p.p.hin)
[hen %give %arow %| -.p.hin u.p.p.hin]~
::
%fact
=* cag cage.p.hin
?+ p.cag ~&(bad-fact+p.cag !!)
%thread-fail
=/ =tang !<(tang q.cag)
%- (slog 'khan-fact' tang)
[hen %give %arow %| p.cag tang]~
::
%thread-done
[hen %give %arow %& %noun q.cag]~
==
==
::
%khan
?. ?=(%arow +<.hin) ~
?~ tea ~
?. ?=(%fyrd -.tea) ~
=* row p.hin
?. ?=(%& -.row)
[hen %give %avow row]~
=/ [=beak =mark]
(read-wire tea)
=/ =tube:clay
(get-tube beak p.p.row mark rof)
=/ =vase
(tube q.p.row)
[hen %give %avow %& mark q.vase]~
==
--