Use $XDG_CACHE_HOME instead of '.ghc-mod' (Fix DanielG/ghc-mod#833)

3 files changed, 21 insertions, 8 deletions

diff --git a/CabalHelper/Compiletime/Compile.hs b/CabalHelper/Compiletime/Compile.hs
index 8da3802..0af950d 100644
--- a/CabalHelper/Compiletime/Compile.hs
+++ b/CabalHelper/Compiletime/Compile.hs
@@ -151,7 +151,7 @@ compileHelper opts cabalVer projdir distdir = do
 compile :: FilePath -> Options -> Compile -> IO (Either ExitCode FilePath)
 compile distdir opts@Options {..} Compile {..} = do
     cnCabalSourceDir <- canonicalizePath `traverse` compCabalSourceDir
-    appdir <- appDataDir
+    appdir <- appCacheDir
 
     let (outdir, exedir, exe, mchsrcdir) =
           case cnCabalSourceDir of
@@ -250,7 +250,7 @@ processFailedException fn exe args rv =
 
 installCabal :: Options -> Version -> IO FilePath
 installCabal opts ver = do
-  appdir <- appDataDir
+  appdir <- appCacheDir
   let sver = showVersion ver
   hPutStr stderr $ printf "\
 \cabal-helper-wrapper: Installing a private copy of Cabal because we couldn't\n\
@@ -435,7 +435,7 @@ errorInstallCabal cabalVer _distdir = panic $ printf "\
 
 cachedExe :: Version -> IO (Maybe FilePath)
 cachedExe compCabalVersion = do
-    appdir <- appDataDir
+    appdir <- appCacheDir
     let exe = appdir </> exeName (Right compCabalVersion)
     exists <- doesFileExist exe
     return $ if exists then Just exe else Nothing
@@ -487,7 +487,7 @@ createPkgDb opts@Options {..} cabalVer = do
 
 getPrivateCabalPkgDb :: Options -> Either String Version -> IO FilePath
 getPrivateCabalPkgDb opts cabalVer = do
-  appdir <- appDataDir
+  appdir <- appCacheDir
   ghcVer <- ghcVersion opts
   return $ appdir </> exeName cabalVer ++ "-ghc" ++ showVersion ghcVer ++ ".package-db"
 
diff --git a/CabalHelper/Compiletime/Wrapper.hs b/CabalHelper/Compiletime/Wrapper.hs
index d002886..dccbc29 100644
--- a/CabalHelper/Compiletime/Wrapper.hs
+++ b/CabalHelper/Compiletime/Wrapper.hs
@@ -51,7 +51,7 @@ usage = do
   hPutStr stderr $ "Usage: " ++ prog ++ " " ++ usageMsg
  where
    usageMsg = "\
-\( print-appdatadir\n\
+\( print-appcachedir\n\
 \| print-build-platform\n\
 \| [--verbose]\n\
 \  [--with-ghc=GHC_PATH]\n\
@@ -124,7 +124,8 @@ main = handlePanic $ do
     [] -> usage
     "help":[] -> usage
     "version":[] -> putStrLn $ showVersion version
-    "print-appdatadir":[] -> putStrLn =<< appDataDir
+    "print-appdatadir":[] -> putStrLn =<< appCacheDir
+    "print-appcachedir":[] -> putStrLn =<< appCacheDir
     "print-build-platform":[] -> putStrLn $ display buildPlatform
 
     projdir:_distdir:"package-id":[] -> do
diff --git a/CabalHelper/Shared/Common.hs b/CabalHelper/Shared/Common.hs
index 3d79f90..588cd03 100644
--- a/CabalHelper/Shared/Common.hs
+++ b/CabalHelper/Shared/Common.hs
@@ -29,6 +29,7 @@ import qualified Data.ByteString as BS
 import qualified Data.ByteString.Char8 as BS8
 import System.Environment
 import System.IO
+import qualified System.Info
 import System.Exit
 import System.Directory
 import System.FilePath
@@ -84,8 +85,19 @@ runReadP p i = case filter ((=="") . snd) $ readP_to_S p i of
                  (a,""):[] -> a
                  _ -> error $ "Error parsing: " ++ show i
 
-appDataDir :: IO FilePath
-appDataDir = (</> "cabal-helper") <$> getAppUserDataDirectory "ghc-mod"
+appCacheDir :: IO FilePath
+appCacheDir =
+    (</> "ghc-mod") <$> getEnvDefault "XDG_CACHE_HOME" (homeRel cache)
+ where
+    getEnvDefault var def = lookupEnv var >>= \m -> case m of Nothing -> def; Just x -> return x
+    homeRel path = (</> path) <$> getHomeDirectory
+    cache =
+        case System.Info.os of
+          "mingw32" -> windowsCache
+          _         -> unixCache
+
+    windowsCache = "Local Settings" </> "Cache"
+    unixCache = ".cache"
 
 isCabalFile :: FilePath -> Bool
 isCabalFile f = takeExtension' f == ".cabal"