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ReadonlyStoreEffects: Add a referrers query.
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@ -21,6 +21,7 @@ library
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build-depends: base >=4.10 && <4.11,
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-- Drop foundation when we can drop cryptonite <0.25
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cryptonite, memory, foundation, basement,
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text, regex-base, regex-tdfa-text
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text, regex-base, regex-tdfa-text,
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hashable, unordered-containers
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hs-source-dirs: src
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default-language: Haskell2010
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@ -3,6 +3,7 @@ Description : Types and effects for interacting with the Nix store.
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Maintainer : Shea Levy <shea@shealevy.com>
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-}
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{-# LANGUAGE DataKinds #-}
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{-# LANGUAGE GeneralizedNewtypeDeriving #-}
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module System.Nix.Store
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( PathName, pathNameContents, pathName
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, PathHashAlgo, Path(..)
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@ -12,9 +13,13 @@ module System.Nix.Store
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import Crypto.Hash (Digest)
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import Crypto.Hash.Truncated (Truncated)
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import Crypto.Hash.Algorithms (SHA256)
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import qualified Data.ByteArray as B
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import Data.Text (Text)
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import Text.Regex.Base.RegexLike (makeRegex, matchTest)
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import Text.Regex.TDFA.Text (Regex)
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import Data.Hashable (Hashable(..), hashPtrWithSalt)
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import Data.HashSet (HashSet)
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import System.IO.Unsafe (unsafeDupablePerformIO)
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-- | The name portion of a Nix path.
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--
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@ -22,7 +27,7 @@ import Text.Regex.TDFA.Text (Regex)
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-- start with a ., and must have at least one character.
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newtype PathName = PathName
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{ pathNameContents :: Text -- ^ The contents of the path name
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}
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} deriving (Hashable)
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-- | A regular expression for matching a valid 'PathName'
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nameRegex :: Regex
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@ -41,6 +46,18 @@ type PathHashAlgo = Truncated SHA256 20
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-- | A path in a store.
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data Path = Path !(Digest PathHashAlgo) !PathName
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-- | Wrapper to defined a 'Hashable' instance for 'Digest'.
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newtype HashableDigest a = HashableDigest (Digest a)
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instance Hashable (HashableDigest a) where
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hashWithSalt s (HashableDigest d) = unsafeDupablePerformIO $
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B.withByteArray d $ \ptr -> hashPtrWithSalt ptr (B.length d) s
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instance Hashable Path where
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hashWithSalt s (Path digest name) =
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s `hashWithSalt`
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(HashableDigest digest) `hashWithSalt` name
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-- | Read-only interactions with a store.
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--
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-- 'rootedPath': A path plus a witness to the fact that the path is
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@ -62,4 +79,6 @@ data ReadonlyStoreEffects rootedPath validPath m =
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fromValidPath :: !(validPath -> rootedPath)
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, -- | Is the given path valid?
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validPath :: !(rootedPath -> m (Maybe validPath))
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, -- | Get the paths that refer to a given path.
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referrers :: !(validPath -> m (HashSet Path))
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}
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