Source file state_rpc.ml
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open! Core
open! Async_kernel
open! Import
open Deferred.Or_error.Let_syntax
include State_rpc_intf
module type S_plus = sig
include S
module Underlying_rpc : sig
val dispatch
: ?metadata:Rpc_metadata.t
-> Rpc.Connection.t
-> query
-> (state * update Pipe.Reader.t) Deferred.Or_error.t
val implement
: ?on_exception:Rpc.On_exception.t
-> ('c -> query -> (state * update Pipe.Reader.t) Deferred.Or_error.t)
-> 'c Rpc.Implementation.t
val description : Rpc.Description.t
end
end
type ('q, 's, 'u) t =
(module S_plus with type query = 'q and type state = 's and type update = 'u)
module Part_or_done = struct
type 'a t =
| Part of 'a
| Done
[@@deriving bin_io]
end
module Response = struct
type ('state_part, 'update_part) t =
| State of 'state_part Part_or_done.t
| Update of 'update_part Part_or_done.t
[@@deriving bin_io]
end
module Direct_writer = struct
module T = Rpc.Pipe_rpc.Direct_stream_writer
type ('state_part, 'update_part) t =
{ writer : ('state_part, 'update_part) Response.t T.t
; state_finalised : unit Ivar.t
}
let wrap writer = { writer; state_finalised = Ivar.create () }
let[@inline] is_state_finalised t = Ivar.is_full t.state_finalised
let state_finalised t = Ivar.read t.state_finalised
let[@cold] raise_state_write_after_finalising () =
raise_s
[%message
"Cannot write state parts to State_rpc.Direct_writer after finalising initial \
state"]
;;
let[@inline] raise_if_finalised t =
if is_state_finalised t then raise_state_write_after_finalising ()
;;
let write_state_without_pushback_exn t state =
raise_if_finalised t;
T.write_without_pushback t.writer (Response.State (Part state))
;;
let finalise_state_without_pushback_exn t =
raise_if_finalised t;
match T.write_without_pushback t.writer (Response.State Done) with
| `Ok ->
Ivar.fill t.state_finalised ();
`Ok
| `Closed -> `Closed
;;
let[@cold] raise_update_write_before_finalising () =
raise_s
[%message
"Cannot write update parts to State_rps.Direct_writer before finalising initial \
state"]
;;
let[@inline] raise_if_not_finalised t =
if not (is_state_finalised t) then raise_update_write_before_finalising ()
;;
let write_update_without_pushback_exn t update =
raise_if_not_finalised t;
T.write_without_pushback t.writer (Response.Update (Part update))
;;
let finalise_update_without_pushback_exn t =
raise_if_not_finalised t;
T.write_without_pushback t.writer (Response.Update Done)
;;
let close t = T.close t.writer
let closed t = T.closed t.writer
let flushed t = T.flushed t.writer
let is_closed t = T.is_closed t.writer
module Group = struct
module T_group = Rpc.Pipe_rpc.Direct_stream_writer.Group
type ('state_part, 'update_part) t = ('state_part, 'update_part) Response.t T_group.t
let create = T_group.create
let flushed_or_closed = T_group.flushed_or_closed
let add_exn t writer =
if not (is_state_finalised writer)
then
raise_s
[%message
"Can't add writer to State_rpc.Direct_writer.Group until it has finalised \
its initial state"];
T_group.add_exn t writer.writer
;;
let remove t writer = T_group.remove t writer.writer
let write_update_without_pushback t update =
T_group.write_without_pushback t (Response.Update (Part update))
;;
let finalise_update_without_pushback t =
T_group.write_without_pushback t (Response.Update Done)
;;
let length = T_group.length
let close_all t =
T_group.to_list t |> List.iter ~f:T.close
;;
end
end
module Make (X : S) = struct
module Underlying_rpc = struct
type query = X.query [@@deriving bin_io]
type response = (X.State.Intermediate.Part.t, X.Update.Intermediate.Part.t) Response.t
[@@deriving bin_io]
type error = Error.Stable.V2.t [@@deriving bin_io]
let rpc =
Rpc.Pipe_rpc.create
()
?client_pushes_back:(if X.client_pushes_back then Some () else None)
~name:X.name
~version:X.version
~bin_query
~bin_response
~bin_error
;;
module type S = sig
type part
include Main.S_rpc with type Intermediate.Part.t = part
end
let write_msg w pipe ~constructor =
let open Deferred.Let_syntax in
let%bind () =
Pipe.transfer pipe w ~f:(fun part -> constructor (Part_or_done.Part part))
in
Pipe.write_if_open w (constructor Done)
;;
let read_msg
(type a p)
(module X : S with type t = a and type part = p)
r
~match_
~noun
=
let rec loop acc =
match%bind Pipe.read r |> Deferred.ok with
| `Eof ->
Deferred.Or_error.errorf
"Streamable.State_rpc: EOF before receiving complete %s"
noun
| `Ok msg ->
(match match_ msg with
| Error e -> Deferred.return (Error e)
| Ok (Part_or_done.Part part) -> loop (X.Intermediate.apply_part acc part)
| Ok Done -> return (X.finalize acc))
in
loop (X.Intermediate.create ())
;;
let description = Rpc.Pipe_rpc.description rpc
module State = struct
include X.State
type part = Intermediate.Part.t
end
module Update = struct
include X.Update
type part = Intermediate.Part.t
end
let implement' ?on_exception f =
Rpc.Pipe_rpc.implement ?on_exception rpc (fun c q ->
let open Deferred.Or_error.Let_syntax in
let%bind state_pipe, update_pipes = f c q in
return
@@ Pipe.create_reader ~close_on_exception:true (fun w ->
let open Deferred.Let_syntax in
upon (Pipe.closed w) (fun () ->
(match Pipe.read_now' update_pipes with
| `Eof | `Nothing_available -> ()
| `Ok queue ->
Queue.iter queue ~f:(fun update_pipe -> Pipe.close_read update_pipe));
Pipe.close_read update_pipes);
let%bind () =
write_msg w state_pipe ~constructor:(fun x -> Response.State x)
in
Pipe.iter update_pipes ~f:(fun update_pipe ->
write_msg w update_pipe ~constructor:(fun x -> Update x))))
;;
let implement ?on_exception f =
implement' ?on_exception (fun c q ->
let open Deferred.Or_error.Let_syntax in
let%bind state, updates = f c q in
return
( State.to_parts state |> Pipe.of_sequence
, Pipe.map updates ~f:(fun update -> Update.to_parts update |> Pipe.of_sequence)
))
;;
let read_state r =
read_msg
(module State)
r
~noun:"state"
~match_:(function
| Response.State x -> Ok x
| Update _ -> Or_error.errorf "Streamable.State_rpc: incomplete state message")
;;
let read_update r =
read_msg
(module Update)
r
~noun:"update"
~match_:(function
| Response.Update x -> Ok x
| State _ -> Or_error.errorf "Streamable.State_rpc: incomplete update message")
;;
let dispatch ?metadata conn query =
let%bind r, _ =
Deferred.Let_syntax.(
Rpc.Pipe_rpc.dispatch ?metadata rpc conn query >>| Or_error.join)
in
let%bind initial_state = read_state r in
let updates =
Pipe.create_reader ~close_on_exception:true (fun w ->
let open Deferred.Let_syntax in
let rec loop () =
match%bind
Deferred.choose
[ Deferred.choice (read_update r) Result.ok
; Deferred.choice (Pipe.closed w) (fun () -> None)
]
with
| Some update ->
let%bind () = Pipe.write_if_open w update in
loop ()
| None -> return ()
in
let%bind () = loop () in
Pipe.close_read r;
return ())
in
return (initial_state, updates)
;;
end
module X_plus = struct
include X
module Underlying_rpc = Underlying_rpc
end
let rpc =
(module X_plus : S_plus
with type query = X.query
and type state = X.state
and type update = X.update)
;;
let implement' = Underlying_rpc.implement'
let implement_direct ?on_exception f =
Rpc.Pipe_rpc.implement_direct ?on_exception Underlying_rpc.rpc (fun c q writer ->
f c q (Direct_writer.wrap writer))
;;
end
let description (type q s u) ((module X) : (q, s, u) t) = X.Underlying_rpc.description
let dispatch (type q s u) ?metadata ((module X) : (q, s, u) t) =
X.Underlying_rpc.dispatch ?metadata
;;
let implement (type q s u) ?on_exception ((module X) : (q, s, u) t) =
X.Underlying_rpc.implement ?on_exception
;;
let bin_query_shape (type q s u) ((module X) : (q, s, u) t) = X.bin_query.shape
let bin_state_shape (type q s u) ((module X) : (q, s, u) t) =
X.State.Intermediate.Part.bin_t.shape
;;
let bin_update_shape (type q s u) ((module X) : (q, s, u) t) =
X.Update.Intermediate.Part.bin_t.shape
;;