Merge pull request #15 from eigengrau/space-leak

Address space leaks in renderFinal and str

brick.cabal

@@ -87,7 +87,8 @@ library
                        contravariant,
                        text,
                        text-zipper >= 0.2.1,
-                       template-haskell
+                       template-haskell,
+                       deepseq >= 1.4 && < 1.5
 
 executable brick-visibility-demo
   if !flag(demos)

src/Brick/Widgets/Core.hs

@@ -78,6 +78,7 @@ import qualified Data.Function as DF
 import Data.List (sortBy, partition)
 import Control.Lens (Lens')
 import qualified Graphics.Vty as V
+import Control.DeepSeq
 
 import Brick.Types
 import Brick.Types.Internal
@@ -125,10 +126,11 @@ str :: String -> Widget
 str s =
     Widget Fixed Fixed $ do
       c <- getContext
-      let theLines = lines s
+      let theLines = fixEmpty <$> (dropUnused . lines) s
           fixEmpty [] = " "
           fixEmpty l = l
-      case fixEmpty <$> theLines of
+          dropUnused l = take (availWidth c) <$> take (availHeight c) l
+      case force theLines of
           [] -> return def
           [one] -> return $ def & imageL .~ (V.string (c^.attrL) one)
           multiple ->

src/Brick/Widgets/Internal.hs

@@ -1,3 +1,5 @@
+{-# LANGUAGE BangPatterns #-}
+
 module Brick.Widgets.Internal
   ( renderFinal
   , cropToContext
@@ -24,7 +26,7 @@ renderFinal :: AttrMap
             -> (RenderState, V.Picture, Maybe CursorLocation)
 renderFinal aMap layerRenders sz chooseCursor rs = (newRS, pic, theCursor)
     where
-        (layerResults, newRS) = flip runState rs $ sequence $
+        (layerResults, !newRS) = flip runState rs $ sequence $
             (\p -> runReaderT p ctx) <$>
             (render <$> cropToContext <$> layerRenders)
         ctx = Context def (fst sz) (snd sz) def aMap