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|
-- |
-- Support for source code annotation feature of GHC. That is the ANN pragma.
--
-- (c) The University of Glasgow 2006
-- (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
--
{-# LANGUAGE DeriveFunctor #-}
module Annotations (
-- * Main Annotation data types
Annotation(..), AnnPayload,
AnnTarget(..), CoreAnnTarget,
getAnnTargetName_maybe,
-- * AnnEnv for collecting and querying Annotations
AnnEnv,
mkAnnEnv, extendAnnEnvList, plusAnnEnv, emptyAnnEnv,
findAnns, findAnnsByTypeRep,
deserializeAnns
) where
import GhcPrelude
import Binary
import Module ( Module )
import Name
import Outputable
import GHC.Serialized
import UniqFM
import Unique
import Control.Monad
import Data.Maybe
import Data.Typeable
import Data.Word ( Word8 )
-- | Represents an annotation after it has been sufficiently desugared from
-- it's initial form of 'HsDecls.AnnDecl'
data Annotation = Annotation {
ann_target :: CoreAnnTarget, -- ^ The target of the annotation
ann_value :: AnnPayload
}
type AnnPayload = Serialized -- ^ The "payload" of an annotation
-- allows recovery of its value at a given type,
-- and can be persisted to an interface file
-- | An annotation target
data AnnTarget name
= NamedTarget name -- ^ We are annotating something with a name:
-- a type or identifier
| ModuleTarget Module -- ^ We are annotating a particular module
deriving (Functor)
-- | The kind of annotation target found in the middle end of the compiler
type CoreAnnTarget = AnnTarget Name
-- | Get the 'name' of an annotation target if it exists.
getAnnTargetName_maybe :: AnnTarget name -> Maybe name
getAnnTargetName_maybe (NamedTarget nm) = Just nm
getAnnTargetName_maybe _ = Nothing
instance Uniquable name => Uniquable (AnnTarget name) where
getUnique (NamedTarget nm) = getUnique nm
getUnique (ModuleTarget mod) = deriveUnique (getUnique mod) 0
-- deriveUnique prevents OccName uniques clashing with NamedTarget
instance Outputable name => Outputable (AnnTarget name) where
ppr (NamedTarget nm) = text "Named target" <+> ppr nm
ppr (ModuleTarget mod) = text "Module target" <+> ppr mod
instance Binary name => Binary (AnnTarget name) where
put_ bh (NamedTarget a) = do
putByte bh 0
put_ bh a
put_ bh (ModuleTarget a) = do
putByte bh 1
put_ bh a
get bh = do
h <- getByte bh
case h of
0 -> liftM NamedTarget $ get bh
_ -> liftM ModuleTarget $ get bh
instance Outputable Annotation where
ppr ann = ppr (ann_target ann)
-- | A collection of annotations
-- Can't use a type synonym or we hit bug #2412 due to source import
newtype AnnEnv = MkAnnEnv (UniqFM [AnnPayload])
-- | An empty annotation environment.
emptyAnnEnv :: AnnEnv
emptyAnnEnv = MkAnnEnv emptyUFM
-- | Construct a new annotation environment that contains the list of
-- annotations provided.
mkAnnEnv :: [Annotation] -> AnnEnv
mkAnnEnv = extendAnnEnvList emptyAnnEnv
-- | Add the given annotation to the environment.
extendAnnEnvList :: AnnEnv -> [Annotation] -> AnnEnv
extendAnnEnvList (MkAnnEnv env) anns
= MkAnnEnv $ addListToUFM_C (++) env $
map (\ann -> (getUnique (ann_target ann), [ann_value ann])) anns
-- | Union two annotation environments.
plusAnnEnv :: AnnEnv -> AnnEnv -> AnnEnv
plusAnnEnv (MkAnnEnv env1) (MkAnnEnv env2) = MkAnnEnv $ plusUFM_C (++) env1 env2
-- | Find the annotations attached to the given target as 'Typeable'
-- values of your choice. If no deserializer is specified,
-- only transient annotations will be returned.
findAnns :: Typeable a => ([Word8] -> a) -> AnnEnv -> CoreAnnTarget -> [a]
findAnns deserialize (MkAnnEnv ann_env)
= (mapMaybe (fromSerialized deserialize))
. (lookupWithDefaultUFM ann_env [])
-- | Find the annotations attached to the given target as 'Typeable'
-- values of your choice. If no deserializer is specified,
-- only transient annotations will be returned.
findAnnsByTypeRep :: AnnEnv -> CoreAnnTarget -> TypeRep -> [[Word8]]
findAnnsByTypeRep (MkAnnEnv ann_env) target tyrep
= [ ws | Serialized tyrep' ws <- lookupWithDefaultUFM ann_env [] target
, tyrep' == tyrep ]
-- | Deserialize all annotations of a given type. This happens lazily, that is
-- no deserialization will take place until the [a] is actually demanded and
-- the [a] can also be empty (the UniqFM is not filtered).
deserializeAnns :: Typeable a => ([Word8] -> a) -> AnnEnv -> UniqFM [a]
deserializeAnns deserialize (MkAnnEnv ann_env)
= mapUFM (mapMaybe (fromSerialized deserialize)) ann_env
|
