Use Settings to avoid querying dirs every time

lib/GHCup/Download.hs

@@ -133,10 +133,10 @@ getDownloadsF urlSource = do
     (OwnSpec   _) -> liftE $ getDownloads urlSource
  where
   readFromCache = do
+    Settings {dirs = Dirs {..}} <- lift ask
     lift $ $(logWarn)
       [i|Could not get download info, trying cached version (this may not be recent!)|]
     let path = view pathL' ghcupURL
-    cacheDir  <- liftIO $ ghcupCacheDir
     yaml_file <- (cacheDir </>) <$> urlBaseName path
     bs        <-
       handleIO' NoSuchThing
@@ -200,8 +200,8 @@ getDownloads urlSource = do
                m1
                L.ByteString
   smartDl uri' = do
+    Settings {dirs = Dirs {..}} <- lift ask
     let path = view pathL' uri'
-    cacheDir  <- liftIO $ ghcupCacheDir
     json_file <- (cacheDir </>) <$> urlBaseName path
     e         <- liftIO $ doesFileExist json_file
     if e
@@ -392,15 +392,15 @@ downloadCached dli mfn = do
   cache <- lift getCache
   case cache of
     True -> do
-      cachedir <- liftIO $ ghcupCacheDir
+      Settings {dirs = Dirs {..}} <- lift ask
       fn       <- maybe (urlBaseName $ view (dlUri % pathL') dli) pure mfn
-      let cachfile = cachedir </> fn
+      let cachfile = cacheDir </> fn
       fileExists <- liftIO $ doesFileExist cachfile
       if
         | fileExists -> do
           liftE $ checkDigest dli cachfile
           pure $ cachfile
-        | otherwise -> liftE $ download dli cachedir mfn
+        | otherwise -> liftE $ download dli cacheDir mfn
     False -> do
       tmp <- lift withGHCupTmpDir
       liftE $ download dli tmp mfn