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module Storage.List (
StoredList,
emptySList, fromSList, storedFromSList,
slistAdd, slistAddS, slistInsert, slistInsertS, slistRemove, slistReplace, slistReplaceS,
mapFromSList, updateOld,
StoreUpdate(..),
withStoredListItem, withStoredListItemS,
) where
import Control.Monad
import Control.Monad.Reader
import Data.List
import Data.Map (Map)
import qualified Data.Map as M
import Data.Maybe
import Storage
import Storage.Internal
data List a = ListNil
| ListItem (Maybe Ref) (Maybe Ref) (Maybe (Stored a)) (StoredList a)
deriving (Show)
type StoredList a = Stored (List a)
instance Storable a => Storable (List a) where
store' ListNil = storeZero
store' (ListItem remove after item next) = storeRec $ do
storeMbRawRef "r" remove
storeMbRawRef "a" after
storeMbRef "i" item
storeRef "n" next
load' = asks snd >>= \case
ZeroObject -> return ListNil
_ ->
loadRec $ ListItem
<$> loadMbRawRef "r"
<*> loadMbRawRef "a"
<*> loadMbRef "i"
<*> loadRef "n"
instance Storable a => ZeroStorable (List a) where
fromZero _ = ListNil
emptySList :: Storable a => Storage -> IO (StoredList a)
emptySList st = wrappedStore st ListNil
fromSList :: StoredList a -> [a]
fromSList = map fromStored . storedFromSList
storedFromSList :: StoredList a -> [Stored a]
storedFromSList = fromSList' []
where fromSList' :: [(Ref, Bool, [Stored a])] -> StoredList a -> [Stored a]
fromSList' _ (Stored _ ListNil) = []
fromSList' repl (Stored cref (ListItem rref aref x rest)) =
case (rref, aref) of
(Nothing, Nothing) -> let (rx, repl') = findRepl cref x repl
in rx ++ fromSList' repl' rest
(Just r , Nothing) -> fromSList' (addReplace cref r x repl) rest
(Nothing, Just a ) -> fromSList' (addInsert cref a x repl) rest
(Just r , Just a ) -> fromSList' (addReplace cref r x $ addInsert cref a x repl) rest
addReplace = findAddRepl False
addInsert = findAddRepl True
findAddRepl :: Bool -> Ref -> Ref -> Maybe (Stored a) -> [(Ref, Bool, [Stored a])] -> [(Ref, Bool, [Stored a])]
findAddRepl keep c t x rs = let (x', rs') = findRepl c x rs
in addRepl keep c t x' rs'
addRepl :: Bool -> Ref -> Ref -> [Stored a] -> [(Ref, Bool, [Stored a])] -> [(Ref, Bool, [Stored a])]
addRepl keep _ t x [] = [(t, keep, x)]
addRepl keep c t x ((pr, pk, px) : rs)
| pr == c = (t , keep, x ++ px) : rs
| pr == t = (t , pk, px ++ x) : rs
| otherwise = (pr, pk, px) : addRepl keep c t x rs
findRepl :: Ref -> Maybe (Stored a) -> [(Ref, Bool, [Stored a])] -> ([Stored a], [(Ref, Bool, [Stored a])])
findRepl _ x [] = (maybeToList x, [])
findRepl c x ((pr, pk, px) : rs)
| pr == c = (if pk then maybe id (:) x px else px, rs)
| otherwise = ((pr, pk, px):) <$> findRepl c x rs
slistAdd :: Storable a => a -> StoredList a -> IO (StoredList a)
slistAdd x next@(Stored (Ref st _) _) = do
sx <- wrappedStore st x
slistAddS sx next
slistAddS :: Storable a => Stored a -> StoredList a -> IO (StoredList a)
slistAddS sx next@(Stored (Ref st _) _) = wrappedStore st (ListItem Nothing Nothing (Just sx) next)
slistInsert :: Storable a => Stored a -> a -> StoredList a -> IO (StoredList a)
slistInsert after x next@(Stored (Ref st _) _) = do
sx <- wrappedStore st x
slistInsertS after sx next
slistInsertS :: Storable a => Stored a -> Stored a -> StoredList a -> IO (StoredList a)
slistInsertS after sx next@(Stored (Ref st _) _) = wrappedStore st $ ListItem Nothing (findSListRef after next) (Just sx) next
slistRemove :: Storable a => Stored a -> StoredList a -> IO (StoredList a)
slistRemove rm next@(Stored (Ref st _) _) = wrappedStore st $ ListItem (findSListRef rm next) Nothing Nothing next
slistReplace :: Storable a => Stored a -> a -> StoredList a -> IO (StoredList a)
slistReplace rm x next@(Stored (Ref st _) _) = do
sx <- wrappedStore st x
slistReplaceS rm sx next
slistReplaceS :: Storable a => Stored a -> Stored a -> StoredList a -> IO (StoredList a)
slistReplaceS rm sx next@(Stored (Ref st _) _) = wrappedStore st $ ListItem (findSListRef rm next) Nothing (Just sx) next
findSListRef :: Stored a -> StoredList a -> Maybe Ref
findSListRef _ (Stored _ ListNil) = Nothing
findSListRef x (Stored ref (ListItem _ _ y next)) | y == Just x = Just ref
| otherwise = findSListRef x next
mapFromSList :: Storable a => StoredList a -> Map RefDigest (Stored a)
mapFromSList list = helper list M.empty
where helper :: Storable a => StoredList a -> Map RefDigest (Stored a) -> Map RefDigest (Stored a)
helper (Stored _ ListNil) cur = cur
helper (Stored _ (ListItem (Just rref) _ (Just x) rest)) cur =
let rxref = case load rref of
ListItem _ _ (Just rx) _ -> sameType rx x $ storedRef rx
_ -> error "mapFromSList: malformed list"
in helper rest $ case M.lookup (refDigest $ storedRef x) cur of
Nothing -> M.insert (refDigest rxref) x cur
Just x' -> M.insert (refDigest rxref) x' cur
helper (Stored _ (ListItem _ _ _ rest)) cur = helper rest cur
sameType :: a -> a -> b -> b
sameType _ _ x = x
updateOld :: Map RefDigest (Stored a) -> Stored a -> Stored a
updateOld m x = fromMaybe x $ M.lookup (refDigest $ storedRef x) m
data StoreUpdate a = StoreKeep
| StoreReplace a
| StoreRemove
withStoredListItem :: (Storable a) => (a -> Bool) -> StoredList a -> (a -> IO (StoreUpdate a)) -> IO (StoredList a)
withStoredListItem p list f = withStoredListItemS (p . fromStored) list (suMap (wrappedStore $ storedStorage list) <=< f . fromStored)
where suMap :: Monad m => (a -> m b) -> StoreUpdate a -> m (StoreUpdate b)
suMap _ StoreKeep = return StoreKeep
suMap g (StoreReplace x) = return . StoreReplace =<< g x
suMap _ StoreRemove = return StoreRemove
withStoredListItemS :: (Storable a) => (Stored a -> Bool) -> StoredList a -> (Stored a -> IO (StoreUpdate (Stored a))) -> IO (StoredList a)
withStoredListItemS p list f = do
case find p $ storedFromSList list of
Just sx -> f sx >>= \case StoreKeep -> return list
StoreReplace nx -> slistReplaceS sx nx list
StoreRemove -> slistRemove sx list
Nothing -> return list
|