Types.hs

{-# LANGUAGE RankNTypes, DeriveGeneric, DeriveAnyClass, MultiParamTypeClasses, ExistentialQuantification, StandaloneDeriving, FlexibleInstances #-}
module ProjectM36.DatabaseContext.Types where
import GHC.Generics
import Control.DeepSeq (NFData)
import ProjectM36.Base
import ProjectM36.Error
import ProjectM36.AccessControlList
import ProjectM36.ValueMarker
import qualified Data.HashSet as HS
import Data.Functor.Identity

data DatabaseContextBase a = DatabaseContext {
  inclusionDependencies :: a InclusionDependencies,
  relationVariables :: a RelationVariables,
  atomFunctions :: a AtomFunctions,
  dbcFunctions :: a DatabaseContextFunctions,
  notifications :: a Notifications,
  typeConstructorMapping :: a TypeConstructorMapping,
  registeredQueries :: a RegisteredQueries,
  acl :: a DatabaseContextACL
  } 

-- | The type of the database context when stored in the graph. It can reference data from other transactions in the graph.
type DatabaseContext = DatabaseContextBase ValueMarker

deriving instance NFData DatabaseContext
deriving instance Generic DatabaseContext

-- | The type of the database context when it is fully resolved (of transaction markers such as in the TransactionRefDatabaseContext); standalone, ready-to-use.
type ResolvedDatabaseContext = DatabaseContextBase Identity

data TransactionIdMarker a = TransactionIdMarker TransactionId a
  deriving (NFData, Generic)

-- | Utility functions to pass to Haskell-written database context functions.
data DatabaseContextFunctionUtils =
  DatabaseContextFunctionUtils {
  executeDatabaseContextExpr :: DatabaseContext -> DatabaseContextExpr -> Either RelationalError DatabaseContext,
  executeRelationalExpr :: DatabaseContext -> RelationalExpr -> Either RelationalError Relation
                               }

type DatabaseContextFunctionBodyType = DatabaseContextFunctionUtils -> [Atom] -> DatabaseContext -> Either RelationalError DatabaseContext
type DatabaseContextFunctions = HS.HashSet DatabaseContextFunction

type DatabaseContextFunction = Function DatabaseContextFunctionBodyType DBCFunctionAccessControlList
type DatabaseContextFunctionBody = FunctionBody DatabaseContextFunctionBodyType