core: improve mkStorePathName and its errors, add test

hnix-store-core/hnix-store-core.cabal

@@ -102,6 +102,7 @@ test-suite core
     Fingerprint
     Hash
     Signature
+    StorePath
   hs-source-dirs:
     tests
   build-tool-depends:

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

@@ -20,7 +20,6 @@ module System.Nix.StorePath
     -- * Manipulating 'StorePathName'
   , InvalidNameError(..)
   , mkStorePathName
-  , validStorePathName
     -- * Reason why a path is not valid
   , InvalidPathError(..)
   , -- * Rendering out 'StorePath's
@@ -119,9 +118,9 @@ mkStorePathHashPart =
 -- | Reason why a path name or output name is not valid
 data InvalidNameError
   = EmptyName
-  | NameTooLong
+  | NameTooLong Int
   | LeadingDot
-  | InvalidCharacter
+  | InvalidCharacters Text
   deriving (Eq, Generic, Hashable, Ord, Show)
 
 -- | Reason why a path is not valid
@@ -137,24 +136,22 @@ data InvalidPathError
 -- | Make @StorePathName@ from @Text@ (name part of the @StorePath@)
 -- or fail with @InvalidNameError@ if it isn't valid
 mkStorePathName :: Text -> Either InvalidNameError StorePathName
-mkStorePathName n =
-  if validStorePathName n
-    then pure $ StorePathName n
-    else Left $ reasonInvalid n
-
-reasonInvalid :: Text -> InvalidNameError
-reasonInvalid n
-  | n == ""                  = EmptyName
-  | Data.Text.length n > 211 = NameTooLong
-  | Data.Text.head n == '.'  = LeadingDot
-  | otherwise                = InvalidCharacter
-
-validStorePathName :: Text -> Bool
-validStorePathName n =
-  n /= ""
-  && Data.Text.length n <= 211
-  && Data.Text.head n /= '.'
-  && Data.Text.all validStorePathNameChar n
+mkStorePathName n
+  | n == ""
+    = Left EmptyName
+  | Data.Text.length n > 211
+    = Left $ NameTooLong (Data.Text.length n)
+  | Data.Text.head n == '.'
+    = Left $ LeadingDot
+  | not
+    $ Data.Text.null
+    $ Data.Text.filter
+        (not . validStorePathNameChar)
+        n
+    = Left
+      $ InvalidCharacters
+      $ Data.Text.filter (not . validStorePathNameChar) n
+  | otherwise = pure $ StorePathName n
 
 validStorePathNameChar :: Char -> Bool
 validStorePathNameChar c =

hnix-store-core/tests/StorePath.hs

@@ -0,0 +1,38 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module StorePath where
+
+import Test.Hspec (Spec, describe, it, shouldBe, shouldSatisfy)
+import qualified Data.Either
+import qualified Data.Text
+
+import System.Nix.StorePath (mkStorePathName)
+
+spec_storePath :: Spec
+spec_storePath = do
+  describe "StorePathName" $ do
+    it "parses valid name" $
+      mkStorePathName "name-dev.dotok"
+      `shouldSatisfy`
+      Data.Either.isRight
+
+    it "fails on empty" $
+      mkStorePathName mempty
+      `shouldBe`
+      Left EmptyName
+
+    it "fails on too long" $
+      mkStorePathName (Data.Text.replicate 256 "n")
+      `shouldBe`
+      Left (NameTooLong 256)
+
+    it "fails on leading dot" $
+      mkStorePathName ".ab"
+      `shouldBe`
+      Left LeadingDot
+
+    it "fails on invalid characters" $
+      mkStorePathName "ab!cd#@"
+      `shouldBe`
+      Left (InvalidCharacters "!#@")