1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
module Erebos.Service (
Service(..),
SomeService(..), someService, someServiceAttr, someServiceID,
SomeServiceState(..), fromServiceState, someServiceEmptyState,
SomeServiceGlobalState(..), fromServiceGlobalState, someServiceEmptyGlobalState,
SomeStorageWatcher(..),
ServiceID, mkServiceID,
ServiceHandler,
ServiceInput(..),
ServiceReply(..),
runServiceHandler,
svcGet, svcSet, svcModify,
svcGetGlobal, svcSetGlobal, svcModifyGlobal,
svcGetLocal, svcSetLocal,
svcSelf,
svcPrint,
replyPacket, replyStored, replyStoredRef,
afterCommit,
) where
import Control.Monad.Except
import Control.Monad.Reader
import Control.Monad.State
import Control.Monad.Writer
import Data.Kind
import Data.Typeable
import Data.UUID (UUID)
import qualified Data.UUID as U
import Erebos.Identity
import {-# SOURCE #-} Erebos.Network
import Erebos.State
import Erebos.Storage
class (Typeable s, Storable s, Typeable (ServiceState s), Typeable (ServiceGlobalState s)) => Service s where
serviceID :: proxy s -> ServiceID
serviceHandler :: Stored s -> ServiceHandler s ()
serviceNewPeer :: ServiceHandler s ()
serviceNewPeer = return ()
type ServiceAttributes s = attr | attr -> s
type ServiceAttributes s = Proxy s
defaultServiceAttributes :: proxy s -> ServiceAttributes s
default defaultServiceAttributes :: ServiceAttributes s ~ Proxy s => proxy s -> ServiceAttributes s
defaultServiceAttributes _ = Proxy
type ServiceState s :: Type
type ServiceState s = ()
emptyServiceState :: proxy s -> ServiceState s
default emptyServiceState :: ServiceState s ~ () => proxy s -> ServiceState s
emptyServiceState _ = ()
type ServiceGlobalState s :: Type
type ServiceGlobalState s = ()
emptyServiceGlobalState :: proxy s -> ServiceGlobalState s
default emptyServiceGlobalState :: ServiceGlobalState s ~ () => proxy s -> ServiceGlobalState s
emptyServiceGlobalState _ = ()
serviceStorageWatchers :: proxy s -> [SomeStorageWatcher s]
serviceStorageWatchers _ = []
data SomeService = forall s. Service s => SomeService (Proxy s) (ServiceAttributes s)
someService :: forall s proxy. Service s => proxy s -> SomeService
someService _ = SomeService @s Proxy (defaultServiceAttributes @s Proxy)
someServiceAttr :: forall s. Service s => ServiceAttributes s -> SomeService
someServiceAttr attr = SomeService @s Proxy attr
someServiceID :: SomeService -> ServiceID
someServiceID (SomeService s _) = serviceID s
data SomeServiceState = forall s. Service s => SomeServiceState (Proxy s) (ServiceState s)
fromServiceState :: Service s => proxy s -> SomeServiceState -> Maybe (ServiceState s)
fromServiceState _ (SomeServiceState _ s) = cast s
someServiceEmptyState :: SomeService -> SomeServiceState
someServiceEmptyState (SomeService p _) = SomeServiceState p (emptyServiceState p)
data SomeServiceGlobalState = forall s. Service s => SomeServiceGlobalState (Proxy s) (ServiceGlobalState s)
fromServiceGlobalState :: Service s => proxy s -> SomeServiceGlobalState -> Maybe (ServiceGlobalState s)
fromServiceGlobalState _ (SomeServiceGlobalState _ s) = cast s
someServiceEmptyGlobalState :: SomeService -> SomeServiceGlobalState
someServiceEmptyGlobalState (SomeService p _) = SomeServiceGlobalState p (emptyServiceGlobalState p)
data SomeStorageWatcher s = forall a. Eq a => SomeStorageWatcher (Stored LocalState -> a) (a -> ServiceHandler s ())
newtype ServiceID = ServiceID UUID
deriving (Eq, Ord, Show, StorableUUID)
mkServiceID :: String -> ServiceID
mkServiceID = maybe (error "Invalid service ID") ServiceID . U.fromString
data ServiceInput s = ServiceInput
{ svcAttributes :: ServiceAttributes s
, svcPeer :: Peer
, svcPeerIdentity :: UnifiedIdentity
, svcServer :: Server
, svcPrintOp :: String -> IO ()
}
data ServiceReply s = ServiceReply (Either s (Stored s)) Bool
| ServiceFinally (IO ())
data ServiceHandlerState s = ServiceHandlerState
{ svcValue :: ServiceState s
, svcGlobal :: ServiceGlobalState s
, svcLocal :: Stored LocalState
}
newtype ServiceHandler s a = ServiceHandler (ReaderT (ServiceInput s) (WriterT [ServiceReply s] (StateT (ServiceHandlerState s) (ExceptT String IO))) a)
deriving (Functor, Applicative, Monad, MonadReader (ServiceInput s), MonadWriter [ServiceReply s], MonadState (ServiceHandlerState s), MonadError String, MonadIO)
instance MonadStorage (ServiceHandler s) where
getStorage = asks $ peerStorage . svcPeer
instance MonadHead LocalState (ServiceHandler s) where
updateLocalHead f = do
(ls, x) <- f =<< gets svcLocal
modify $ \s -> s { svcLocal = ls }
return x
runServiceHandler :: Service s => Head LocalState -> ServiceInput s -> ServiceState s -> ServiceGlobalState s -> ServiceHandler s () -> IO ([ServiceReply s], (ServiceState s, ServiceGlobalState s))
runServiceHandler h input svc global shandler = do
let sstate = ServiceHandlerState { svcValue = svc, svcGlobal = global, svcLocal = headStoredObject h }
ServiceHandler handler = shandler
(runExceptT $ flip runStateT sstate $ execWriterT $ flip runReaderT input $ handler) >>= \case
Left err -> do
svcPrintOp input $ "service failed: " ++ err
return ([], (svc, global))
Right (rsp, sstate')
| svcLocal sstate' == svcLocal sstate -> return (rsp, (svcValue sstate', svcGlobal sstate'))
| otherwise -> replaceHead h (svcLocal sstate') >>= \case
Left (Just h') -> runServiceHandler h' input svc global shandler
_ -> return (rsp, (svcValue sstate', svcGlobal sstate'))
svcGet :: ServiceHandler s (ServiceState s)
svcGet = gets svcValue
svcSet :: ServiceState s -> ServiceHandler s ()
svcSet x = modify $ \st -> st { svcValue = x }
svcModify :: (ServiceState s -> ServiceState s) -> ServiceHandler s ()
svcModify f = modify $ \st -> st { svcValue = f (svcValue st) }
svcGetGlobal :: ServiceHandler s (ServiceGlobalState s)
svcGetGlobal = gets svcGlobal
svcSetGlobal :: ServiceGlobalState s -> ServiceHandler s ()
svcSetGlobal x = modify $ \st -> st { svcGlobal = x }
svcModifyGlobal :: (ServiceGlobalState s -> ServiceGlobalState s) -> ServiceHandler s ()
svcModifyGlobal f = modify $ \st -> st { svcGlobal = f (svcGlobal st) }
svcGetLocal :: ServiceHandler s (Stored LocalState)
svcGetLocal = gets svcLocal
svcSetLocal :: Stored LocalState -> ServiceHandler s ()
svcSetLocal x = modify $ \st -> st { svcLocal = x }
svcSelf :: ServiceHandler s UnifiedIdentity
svcSelf = maybe (throwError "failed to validate own identity") return .
validateExtendedIdentity . lsIdentity . fromStored =<< svcGetLocal
svcPrint :: String -> ServiceHandler s ()
svcPrint str = afterCommit . ($ str) =<< asks svcPrintOp
replyPacket :: Service s => s -> ServiceHandler s ()
replyPacket x = tell [ServiceReply (Left x) True]
replyStored :: Service s => Stored s -> ServiceHandler s ()
replyStored x = tell [ServiceReply (Right x) True]
replyStoredRef :: Service s => Stored s -> ServiceHandler s ()
replyStoredRef x = tell [ServiceReply (Right x) False]
afterCommit :: IO () -> ServiceHandler s ()
afterCommit x = tell [ServiceFinally x]
|