Store history in XDG data directory

Author: xsebek

src/Swarm/TUI/Controller.hs

@@ -51,9 +51,10 @@ import Control.Monad.State
 import Data.Bits
 import Data.Either (isRight)
 import Data.Int (Int64)
-import Data.Maybe (isJust)
+import Data.Maybe (isJust, mapMaybe)
 import qualified Data.Set as S
 import qualified Data.Text as T
+import qualified Data.Text.IO as T
 import Linear
 import System.Clock
 import Witch (into)
@@ -150,16 +151,15 @@ toggleModal s modal = do
 --   the updated REPL history to a @.swarm_history@ file.
 shutdown :: AppState -> EventM Name (Next AppState)
 shutdown s = do
+  let hist = mapMaybe getNewEntry (s ^. uiState . uiReplHistory)
+  liftIO $ (`T.appendFile` T.unlines hist) =<< getSwarmHistoryPath True
   let s' = s & uiState . uiReplHistory . traverse %~ markOld
-      hist = filter isEntry (s' ^. uiState . uiReplHistory)
-  liftIO $ writeFile ".swarm_history" (show hist)
   halt s'
  where
   markOld (REPLEntry _ e) = REPLEntry False e
   markOld r = r
-
-  isEntry REPLEntry {} = True
-  isEntry _ = False
+  getNewEntry (REPLEntry True t) = Just t
+  getNewEntry _ = Nothing
 
 ------------------------------------------------------------
 -- Handling Frame events

src/Swarm/TUI/Model.hs

@@ -80,9 +80,9 @@ import Control.Monad.State
 import Data.List (findIndex, sortOn)
 import Data.Maybe (fromMaybe)
 import Data.Text (Text)
+import qualified Data.Text as T
 import qualified Data.Vector as V
 import System.Clock
-import Text.Read (readMaybe)
 
 import Brick
 import Brick.Focus
@@ -327,14 +327,15 @@ initLgTicksPerSecond = 3 -- 2^3 = 8 ticks / second
 --   time.
 initUIState :: ExceptT Text IO UIState
 initUIState = liftIO $ do
-  mhist <- (>>= readMaybe @[REPLHistItem]) <$> readFileMay ".swarm_history"
+  historyT <- readFileMayT =<< getSwarmHistoryPath False
+  let history = maybe [] (map (REPLEntry False) . reverse . T.lines) historyT
   startTime <- getTime Monotonic
   return $
     UIState
       { _uiFocusRing = initFocusRing
       , _uiReplForm = initReplForm
       , _uiReplType = Nothing
-      , _uiReplHistory = mhist ? []
+      , _uiReplHistory = history
       , _uiReplHistIdx = -1
       , _uiReplLast = ""
       , _uiInventory = Nothing

src/Swarm/Util.hs

@@ -24,9 +24,13 @@ module Swarm.Util (
   (?),
   maxOn,
   maximum0,
-  readFileMay,
   cycleEnum,
 
+  -- * Directory utilities
+  readFileMay,
+  readFileMayT,
+  getSwarmHistoryPath,
+
   -- * English language utilities
   quote,
   squote,
@@ -46,20 +50,27 @@ module Swarm.Util (
   liftText,
 ) where
 
-import Control.Monad (unless)
+import Control.Monad (unless, when)
 import Control.Monad.Error.Class
 import Data.Either.Validation
 import Data.Int (Int64)
 import Data.Maybe (fromMaybe)
 import Data.Text (Text)
 import qualified Data.Text as T
+import qualified Data.Text.IO as T
 import Data.Yaml
 import Language.Haskell.TH
 import Language.Haskell.TH.Syntax (lift)
 import Linear (V2)
 import qualified NLP.Minimorph.English as MM
 import NLP.Minimorph.Util ((<+>))
-import System.Directory (doesFileExist)
+import System.Directory (
+  XdgDirectory (XdgData),
+  createDirectoryIfMissing,
+  getXdgDirectory,
+ )
+import System.FilePath
+import System.IO.Error (catchIOError)
 
 infixr 1 ?
 
@@ -83,27 +94,38 @@ maximum0 :: (Num a, Ord a) => [a] -> a
 maximum0 [] = 0
 maximum0 xs = maximum xs
 
--- | Safely attempt to read a file, returning @Nothing@ if the file
---   does not exist.  \"Safely\" should be read in scare quotes here,
---   since /e.g./ we do nothing to guard against the possibility of a
---   race condition where the file is deleted after the existence
---   check but before trying to read it.  But it's not like we're
---   worried about security or anything here.
-readFileMay :: FilePath -> IO (Maybe String)
-readFileMay file = do
-  b <- doesFileExist file
-  case b of
-    False -> return Nothing
-    True -> Just <$> readFile file
-
 -- | Take the successor of an 'Enum' type, wrapping around when it
 --   reaches the end.
 cycleEnum :: (Eq e, Enum e, Bounded e) => e -> e
 cycleEnum e
   | e == maxBound = minBound
   | otherwise = succ e
 
---------------------------------------------------
+------------------------------------------------------------
+-- Directory stuff
+
+-- | Safely attempt to read a file.
+readFileMay :: FilePath -> IO (Maybe String)
+readFileMay = catchIO . readFile
+
+-- | Safely attempt to (efficiently) read a file.
+readFileMayT :: FilePath -> IO (Maybe Text)
+readFileMayT = catchIO . T.readFile
+
+-- | Turns any IO error into Nothing.
+catchIO :: IO a -> IO (Maybe a)
+catchIO act = (Just <$> act) `catchIOError` (\_ -> return Nothing)
+
+-- | Get path to swarm history, optionally creating necessary
+--   directories. This could fail if user has bad permissions
+--   on his own $HOME or $XDG_DATA_HOME which is unlikely.
+getSwarmHistoryPath :: Bool -> IO FilePath
+getSwarmHistoryPath createDirs = do
+  swarmData <- getXdgDirectory XdgData "swarm"
+  when createDirs (createDirectoryIfMissing True swarmData)
+  pure (swarmData </> "history")
+
+------------------------------------------------------------
 -- Some language-y stuff
 
 -- | Prepend a noun with the proper indefinite article (\"a\" or \"an\").

swarm.cabal

@@ -96,6 +96,7 @@ library
                       containers                    >= 0.6.2 && < 0.7,
                       directory                     >= 1.3 && < 1.4,
                       either                        >= 5.0 && < 5.1,
+                      filepath                      >= 1.4 && < 1.5,
                       hashable                      >= 1.3.4 && < 1.4,
                       megaparsec                    >= 9.0 && < 9.2,
                       hsnoise                       >= 0.0.2 && < 0.1,