Add xdg support wrt #39

lib/GHCup.hs

@@ -270,7 +270,7 @@ installCabalBindist dlinfo ver (PlatformRequest {..}) = do
   installCabal' path inst = do
     lift $ $(logInfo) "Installing cabal"
     let cabalFile = [rel|cabal|]
-    liftIO $ createDirIfMissing newDirPerms inst
+    liftIO $ createDirRecursive newDirPerms inst
     destFileName <- lift $ parseRel (toFilePath cabalFile <> "-" <> verToBS ver)
     handleIO (throwE . CopyError . show) $ liftIO $ copyFile
       (path </> cabalFile)
@@ -360,7 +360,7 @@ setGHC ver sghc = do
 
     -- create symlink
     let fullF = bindir </> targetFile
-    let destL = ghcLinkDestination (toFilePath file) ver
+    destL <- ghcLinkDestination (toFilePath file) ver
     lift $ $(logDebug) [i|ln -s #{destL} #{toFilePath fullF}|]
     liftIO $ createSymlink fullF destL
 
@@ -631,7 +631,7 @@ rmCabalVer :: (MonadThrow m, MonadLogger m, MonadIO m, MonadFail m)
            => Version
            -> Excepts '[NotInstalled] m ()
 rmCabalVer ver = do
-  whenM (fmap not $ liftIO $ cabalInstalled ver) $ throwE (NotInstalled GHC (prettyVer ver))
+  whenM (fmap not $ liftIO $ cabalInstalled ver) $ throwE (NotInstalled Cabal (prettyVer ver))
 
   cSet      <- liftIO cabalSet
 

lib/GHCup/Download.hs

@@ -226,7 +226,7 @@ getDownloads urlSource = do
           else -- access in less than 5 minutes, re-use file
                liftIO $ readFile json_file
       else do
-        liftIO $ createDirIfMissing newDirPerms cacheDir
+        liftIO $ createDirRecursive newDirPerms cacheDir
         getModTime >>= \case
           Just modTime -> dlWithMod modTime json_file
           Nothing -> do

lib/GHCup/Utils.hs

@@ -97,11 +97,15 @@ import qualified Text.Megaparsec               as MP
 
 
 -- | The symlink destination of a ghc tool.
-ghcLinkDestination :: ByteString -- ^ the tool, such as 'ghc', 'haddock' etc.
+ghcLinkDestination :: (MonadThrow m, MonadIO m)
+                   => ByteString -- ^ the tool, such as 'ghc', 'haddock' etc.
                    -> GHCTargetVersion
-                   -> ByteString
-ghcLinkDestination tool ver =
-  "../ghc/" <> E.encodeUtf8 (prettyTVer ver) <> "/bin/" <> tool
+                   -> m ByteString
+ghcLinkDestination tool ver = do
+  t <- parseRel tool
+  bin <- liftIO ghcupBinDir
+  ghcd <- liftIO $ ghcupGHCDir ver
+  pure (relativeSymlink bin (ghcd </> [rel|bin|] </> t))
 
 
 -- | Removes the minor GHC symlinks, e.g. ghc-8.6.5.
@@ -201,25 +205,26 @@ ghcSet mtarget = do
   liftIO $ handleIO' NoSuchThing (\_ -> pure $ Nothing) $ do
     link <- readSymbolicLink $ toFilePath ghcBin
     Just <$> ghcLinkVersion link
+
+ghcLinkVersion :: MonadThrow m => ByteString -> m GHCTargetVersion
+ghcLinkVersion bs = do
+  t <- throwEither $ E.decodeUtf8' bs
+  throwEither $ MP.parse parser "ghcLinkVersion" t
  where
-  ghcLinkVersion :: MonadThrow m => ByteString -> m GHCTargetVersion
-  ghcLinkVersion bs = do
-    t <- throwEither $ E.decodeUtf8' bs
-    throwEither $ MP.parse parser "" t
-   where
-    parser =
-      MP.chunk "../ghc/"
-        *> (do
-             r    <- parseUntil1 (MP.chunk "/")
-             rest <- MP.getInput
-             MP.setInput r
-             x <- ghcTargetVerP
-             MP.setInput rest
-             pure x
-           )
-        <* MP.chunk "/"
-        <* MP.takeRest
-        <* MP.eof
+  parser =
+      (do
+         _    <- parseUntil1 (MP.chunk "/ghc/")
+         _    <- MP.chunk "/ghc/"
+         r    <- parseUntil1 (MP.chunk "/")
+         rest <- MP.getInput
+         MP.setInput r
+         x <- ghcTargetVerP
+         MP.setInput rest
+         pure x
+       )
+      <* MP.chunk "/"
+      <* MP.takeRest
+      <* MP.eof
 
 
 -- | Get all installed GHCs by reading ~/.ghcup/ghc/<dir>.
@@ -256,15 +261,19 @@ cabalInstalled ver = do
 
 
 -- Return the currently set cabal version, if any.
-cabalSet :: (MonadIO m, MonadThrow m) => m (Maybe Version)
+cabalSet :: (MonadIO m, MonadThrow m, MonadCatch m) => m (Maybe Version)
 cabalSet = do
   cabalbin <- (</> [rel|cabal|]) <$> liftIO ghcupBinDir
-  b        <- fmap (== SymbolicLink) $ liftIO $ getFileType cabalbin
+  b        <- handleIO (\_ -> pure False) $ fmap (== SymbolicLink) $ liftIO $ getFileType cabalbin
   if
     | b -> do
       liftIO $ handleIO' NoSuchThing (\_ -> pure $ Nothing) $ do
-        link <- readSymbolicLink $ toFilePath cabalbin
-        Just <$> linkVersion link
+        broken <- isBrokenSymlink cabalbin
+        if broken
+          then pure Nothing
+          else do
+            link <- readSymbolicLink $ toFilePath cabalbin
+            Just <$> linkVersion link
     | otherwise -> do -- legacy behavior
       mc <- liftIO $ handleIO (\_ -> pure Nothing) $ fmap Just $ executeOut
         cabalbin

lib/GHCup/Utils/Dirs.hs

@@ -24,6 +24,7 @@ import           Control.Exception.Safe
 import           Control.Monad
 import           Control.Monad.Reader
 import           Control.Monad.Trans.Resource
+import           Data.ByteString                ( ByteString )
 import           Data.Maybe
 import           HPath
 import           HPath.IO
@@ -35,6 +36,7 @@ import           Prelude                 hiding ( abs
 import           System.Posix.Env.ByteString    ( getEnv
                                                 , getEnvDefault
                                                 )
+import           System.Posix.FilePath  hiding  ( (</>) )
 import           System.Posix.Temp.ByteString   ( mkdtemp )
 
 import qualified Data.ByteString.UTF8          as UTF8
@@ -51,12 +53,25 @@ import qualified Text.Megaparsec               as MP
 
 
 -- | ~/.ghcup by default
+--
+-- If 'GHCUP_USE_XDG_DIRS' is set (to anything),
+-- then uses 'XDG_DATA_HOME/ghcup' as per xdg spec.
 ghcupBaseDir :: IO (Path Abs)
 ghcupBaseDir = do
-  bdir <- getEnv "GHCUP_INSTALL_BASE_PREFIX" >>= \case
-    Just r  -> parseAbs r
-    Nothing -> liftIO getHomeDirectory
-  pure (bdir </> [rel|.ghcup|])
+  xdg <- useXDG
+  if xdg
+    then do
+      bdir <- getEnv "XDG_DATA_HOME" >>= \case
+        Just r  -> parseAbs r
+        Nothing -> do
+          home <- liftIO getHomeDirectory
+          pure (home </> [rel|.local/share|])
+      pure (bdir </> [rel|ghcup|])
+    else do
+      bdir <- getEnv "GHCUP_INSTALL_BASE_PREFIX" >>= \case
+        Just r  -> parseAbs r
+        Nothing -> liftIO getHomeDirectory
+      pure (bdir </> [rel|.ghcup|])
 
 
 -- | ~/.ghcup/ghc by default.
@@ -82,14 +97,54 @@ parseGHCupGHCDir (toFilePath -> f) = do
   throwEither $ MP.parse ghcTargetVerP "" fp
 
 
+-- | If 'GHCUP_USE_XDG_DIRS' is set (to anything),
+-- then uses 'XDG_BIN_HOME' env var or defaults to '~/.local/bin'
+-- (which, sadly is not strictly xdg spec).
 ghcupBinDir :: IO (Path Abs)
-ghcupBinDir = ghcupBaseDir <&> (</> [rel|bin|])
+ghcupBinDir = do
+  xdg <- useXDG
+  if xdg
+    then do
+      getEnv "XDG_BIN_HOME" >>= \case
+        Just r  -> parseAbs r
+        Nothing -> do
+          home <- liftIO getHomeDirectory
+          pure (home </> [rel|.local/bin|])
+    else ghcupBaseDir <&> (</> [rel|bin|])
 
+-- | Defaults to '~/.ghcup/cache'.
+--
+-- If 'GHCUP_USE_XDG_DIRS' is set (to anything),
+-- then uses 'XDG_CACHE_HOME/ghcup' as per xdg spec.
 ghcupCacheDir :: IO (Path Abs)
-ghcupCacheDir = ghcupBaseDir <&> (</> [rel|cache|])
+ghcupCacheDir = do
+  xdg <- useXDG
+  if xdg
+    then do
+      bdir <- getEnv "XDG_CACHE_HOME" >>= \case
+        Just r  -> parseAbs r
+        Nothing -> do
+          home <- liftIO getHomeDirectory
+          pure (home </> [rel|.cache|])
+      pure (bdir </> [rel|ghcup|])
+    else ghcupBaseDir <&> (</> [rel|cache|])
 
+-- | Defaults to '~/.ghcup/logs'.
+--
+-- If 'GHCUP_USE_XDG_DIRS' is set (to anything),
+-- then uses 'XDG_CACHE_HOME/ghcup/logs' as per xdg spec.
 ghcupLogsDir :: IO (Path Abs)
-ghcupLogsDir = ghcupBaseDir <&> (</> [rel|logs|])
+ghcupLogsDir = do
+  xdg <- useXDG
+  if xdg
+    then do
+      bdir <- getEnv "XDG_CACHE_HOME" >>= \case
+        Just r  -> parseAbs r
+        Nothing -> do
+          home <- liftIO getHomeDirectory
+          pure (home </> [rel|.cache|])
+      pure (bdir </> [rel|ghcup/logs|])
+    else ghcupBaseDir <&> (</> [rel|logs|])
 
 
 mkGhcupTmpDir :: (MonadThrow m, MonadIO m) => m (Path Abs)
@@ -116,3 +171,24 @@ getHomeDirectory = do
     Nothing -> do
       h <- PU.homeDirectory <$> (PU.getEffectiveUserID >>= PU.getUserEntryForID)
       parseAbs $ UTF8.fromString h -- this is a guess
+
+
+useXDG :: IO Bool
+useXDG = isJust <$> getEnv "GHCUP_USE_XDG_DIRS"
+
+
+relativeSymlink :: Path Abs  -- ^ the path in which to create the symlink
+                -> Path Abs  -- ^ the symlink destination
+                -> ByteString
+relativeSymlink (toFilePath -> p1) (toFilePath -> p2) =
+  let d1            = splitDirectories p1
+      d2            = splitDirectories p2
+      common        = takeWhile (\(x, y) -> x == y) $ zip d1 d2
+      cPrefix       = drop (length common) d1
+  in  joinPath (replicate (length cPrefix) "..")
+        <> joinPath ("/" : (drop (length common) d2))
+
+
+
+
+

lib/GHCup/Utils/File.hs

@@ -427,3 +427,12 @@ findFiles' path parser = do
                              Right p' -> isJust $ MP.parseMaybe parser p')
     $ dirContentsStream dirStream
   pure $ join $ fmap parseRel f
+
+
+isBrokenSymlink :: Path Abs -> IO Bool
+isBrokenSymlink p =
+  handleIO
+      (\e -> if ioeGetErrorType e == NoSuchThing then pure True else throwIO e)
+    $ do
+        _ <- canonicalizePath p
+        pure False

lib/GHCup/Utils/Logger.hs

@@ -65,7 +65,7 @@ initGHCupFileLogging :: Path Rel -> IO (Path Abs)
 initGHCupFileLogging context = do
   logs <- ghcupLogsDir
   let logfile = logs </> context
-  createDirIfMissing newDirPerms logs
+  createDirRecursive newDirPerms logs
   hideError doesNotExistErrorType $ deleteFile logfile
   createRegularFile newFilePerms logfile
   pure logfile