add a readonly computeStorePathForPath

Author: layus

hnix-store-core/src/System/Nix/ReadonlyStore.hs

@@ -2,6 +2,8 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE AllowAmbiguousTypes #-}
+{-# LANGUAGE TypeFamilies #-}
 
 module System.Nix.ReadonlyStore where
 
@@ -13,7 +15,9 @@ import qualified Data.Text                     as T
 import qualified Data.HashSet                  as HS
 import           Data.Text.Encoding
 import           System.Nix.Hash
+import           System.Nix.Nar
 import           System.Nix.StorePath
+import           Control.Monad.State.Strict
 
 
 makeStorePath
@@ -70,3 +74,22 @@ makeFixedOutputPath fp recursive h =
 computeStorePathForText
   :: FilePath -> StorePathName -> ByteString -> (StorePathSet -> StorePath)
 computeStorePathForText fp nm = makeTextPath fp nm . hash
+
+computeStorePathForPath :: forall a. (ValidAlgo a, NamedAlgo a)
+           => StorePathName        -- ^ Name part of the newly created `StorePath`
+           -> FilePath             -- ^ Local `FilePath` to add
+           -> Bool                 -- ^ Add target directory recursively
+           -> (FilePath -> Bool)   -- ^ Path filter function
+           -> Bool                 -- ^ Only used by local store backend
+           -> IO StorePath
+computeStorePathForPath name pth recursive _pathFilter _repair = do
+  selectedHash <- if recursive then recursiveContentHash else flatContentHash
+  pure $ makeFixedOutputPath "/nix/store" recursive selectedHash name
+ where
+  recursiveContentHash :: IO (Digest a)
+  recursiveContentHash = finalize @a <$> execStateT streamNarUpdate (initialize @a)
+  streamNarUpdate :: StateT (AlgoCtx a) IO ()
+  streamNarUpdate = streamNarIO (modify . flip (update @a)) narEffectsIO pth
+
+  flatContentHash :: IO (Digest a)
+  flatContentHash = hashLazy <$> narReadFile narEffectsIO pth