Files
simplex-chat/definitions/src/Simplex/Messaging/Protocol.hs
Evgeny Poberezkin 7dce45ea2a add comment
2020-05-09 13:28:05 +01:00

107 lines
3.8 KiB
Haskell

{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE NoStarIsType #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
module Simplex.Messaging.Protocol where
import Data.Kind
import Data.Singletons()
import Data.Singletons.TH
import Data.Type.Predicate
import Data.Type.Predicate.Auto
$(singletons [d|
data Participant = Recipient | Broker | Sender
data ConnectionState = New -- (participants: all) connection created (or received from sender)
| Pending -- (recipient) sent to sender out-of-band
| Confirmed -- (recipient) confirmed by sender with the broker
| Secured -- (all) secured with the broker
| Disabled -- (broker, recipient) disabled with the broker by recipient
| Drained -- (broker, recipient) drained (no messages)
| None -- (all) not available or removed from the broker
|])
-- broker connection states
type Prf1 t a = Auto (TyPred t) a
data BrokerCS :: ConnectionState -> Type where
BrkNew :: BrokerCS 'New
BrkSecured :: BrokerCS 'Secured
BrkDisabled :: BrokerCS 'Disabled
BrkDrained :: BrokerCS 'Drained
BrkNone :: BrokerCS 'None
instance Auto (TyPred BrokerCS) 'New where auto = autoTC
instance Auto (TyPred BrokerCS) 'Secured where auto = autoTC
instance Auto (TyPred BrokerCS) 'Disabled where auto = autoTC
instance Auto (TyPred BrokerCS) 'Drained where auto = autoTC
instance Auto (TyPred BrokerCS) 'None where auto = autoTC
-- sender connection states
data SenderCS :: ConnectionState -> Type where
SndNew :: SenderCS 'New
SndConfirmed :: SenderCS 'Confirmed
SndSecured :: SenderCS 'Secured
SndNone :: SenderCS 'None
instance Auto (TyPred SenderCS) 'New where auto = autoTC
instance Auto (TyPred SenderCS) 'Confirmed where auto = autoTC
instance Auto (TyPred SenderCS) 'Secured where auto = autoTC
instance Auto (TyPred SenderCS) 'None where auto = autoTC
-- allowed participant connection states
data HasState (p :: Participant) (s :: ConnectionState) :: Type where
RcpHasState :: HasState 'Recipient s
BrkHasState :: Prf1 BrokerCS s => HasState 'Broker s
SndHasState :: Prf1 SenderCS s => HasState 'Sender s
class Prf t p s where auto' :: t p s
instance Prf HasState 'Recipient s
where auto' = RcpHasState
instance Prf1 BrokerCS s => Prf HasState 'Broker s
where auto' = BrkHasState
instance Prf1 SenderCS s => Prf HasState 'Sender s
where auto' = SndHasState
-- established connection states (used by broker and recipient)
data EstablishedState (s :: ConnectionState) :: Type where
ESecured :: EstablishedState 'Secured
EDisabled :: EstablishedState 'Disabled
EDrained :: EstablishedState 'Drained
-- data types for connection states of all participants
infixl 7 <==>, <==| -- types
infixl 7 :<==>, :<==| -- constructors
data (<==>) (rs :: ConnectionState) (bs :: ConnectionState) :: Type where
(:<==>) :: (Prf HasState 'Recipient rs, Prf HasState 'Broker bs)
=> Sing rs
-> Sing bs
-> rs <==> bs
data family (<==|) rb (ss :: ConnectionState)
data instance (<==|) (rs <==> bs) ss :: Type where
(:<==|) :: Prf HasState 'Sender ss
=> rs <==> bs
-> Sing ss
-> rs <==> bs <==| ss
-- recipient <==> broker <==| sender
st2 :: 'Pending <==> 'New <==| 'Confirmed
st2 = SPending :<==> SNew :<==| SConfirmed
-- this must not type check
-- stBad :: 'Pending <==> 'Confirmed <==| 'Confirmed
-- stBad = SPending :<==> SConfirmed :<==| SConfirmed