Move getDataFile function so that it is not exposed to the outside world

compiler/Build/Utils.hs

@@ -1,8 +1,11 @@
 {-# OPTIONS_GHC -W #-}
 module Build.Utils where
 
+import System.Directory (doesFileExist)
+import System.Environment (getEnv)
 import System.FilePath ((</>), replaceExtension)
 import qualified Build.Flags as Flag
+import qualified Paths_Elm as This
 
 buildPath :: Flag.Flags -> FilePath -> String -> FilePath
 buildPath flags filePath ext =
@@ -19,3 +22,14 @@ elmo flags filePath =
 elmi :: Flag.Flags -> FilePath -> FilePath
 elmi flags filePath =
     cachePath flags filePath "elmi"
+
+-- |The absolute path to a data file
+getDataFile :: FilePath -> IO FilePath
+getDataFile name = do
+  path <- This.getDataFileName name
+  exists <- doesFileExist path
+  if exists
+    then return path
+    else do
+      env <- getEnv "ELM_HOME"
+      return (env </> name)

compiler/Elm/Internal/Paths.hs

@@ -1,11 +1,8 @@
 {-# OPTIONS_GHC -Wall #-}
 module Elm.Internal.Paths where
 
-import System.Directory (doesFileExist)
+import Build.Utils (getDataFile)
-import System.Environment (getEnv)
-import System.FilePath ((</>))
 import System.IO.Unsafe (unsafePerformIO)
-import qualified Paths_Elm as This
 
 -- |Name of directory for all of a project's dependencies.
 dependencyDirectory :: FilePath
@@ -25,14 +22,3 @@ runtime = unsafePerformIO $ getDataFile "elm-runtime.js"
 -- |The absolute path to Elm's core library documentation.
 docs :: FilePath
 docs = unsafePerformIO $ getDataFile "docs.json"
-
--- |The absolute path to a data file
-getDataFile :: FilePath -> IO FilePath
-getDataFile name = do
-      path <- This.getDataFileName name
-      exists <- doesFileExist path
-      if exists
-        then return path
-        else do
-          env <- getEnv "ELM_HOME"
-          return (env </> name)

compiler/Metadata/Prelude.hs

@@ -3,11 +3,11 @@ module Metadata.Prelude (interfaces, add) where
 
 import qualified Data.Map as Map
 import qualified Control.Exception as E
-import qualified Elm.Internal.Paths as Path
 import System.Exit
 import System.IO
 import SourceSyntax.Module
 import qualified Build.Interface as Interface
+import Build.Utils (getDataFile)
 
 add :: Bool -> Module def -> Module def
 add noPrelude (Module name exs ims decls) = Module name exs (customIms ++ ims) decls
@@ -31,7 +31,7 @@ interfaces :: Bool -> IO Interfaces
 interfaces noPrelude =
     if noPrelude
     then return Map.empty
-    else safeReadDocs =<< Path.getDataFile "interfaces.data"
+    else safeReadDocs =<< getDataFile "interfaces.data"
 
 safeReadDocs :: FilePath -> IO Interfaces
 safeReadDocs name =