Change the API of unsafeWriteIndex and add fromListIO

src/Streamly/Internal/Data/Array/Foreign/Mut/Type.hs

@@ -26,6 +26,7 @@ module Streamly.Internal.Data.Array.Foreign.Mut.Type
     -- * From containers
     , fromList
     , fromListN
+    , fromListIO
     , fromStreamDN
     , fromStreamD
 
@@ -303,15 +304,12 @@ unsafeWithNewArray count f = do
 -------------------------------------------------------------------------------
 
 {-# INLINE unsafeWriteIndex #-}
-unsafeWriteIndex :: forall a. Storable a => Array a -> Int -> a -> IO (Array a)
-unsafeWriteIndex arr@Array {..} i x =
+unsafeWriteIndex :: forall a. Storable a => Array a -> Int -> a -> IO ()
+unsafeWriteIndex Array {..} i x =
     unsafeWithForeignPtr aStart
         $ \begin -> do
               poke (begin `plusPtr` (i * sizeOf (undefined :: a))) x
-              return arr
 
--- XXX grow the array when we are beyond bound.
---
 -- Internal routine for when the array is being created. Appends one item at
 -- the end of the array. Useful when sequentially writing a stream to the
 -- array.
@@ -981,6 +979,11 @@ fromStreamD m = do
     len <- K.foldl' (+) 0 (K.map length buffered)
     fromStreamDN len $ D.unfoldMany read $ D.fromStreamK buffered
 
+-- XXX Replace fromList with this
+{-# INLINABLE fromListIO #-}
+fromListIO :: Storable a => [a] -> IO (Array a)
+fromListIO xs = fromStreamD $ D.fromList xs
+
 -- | Create an 'Array' from a list. The list must be of finite size.
 --
 -- @since 0.7.0

test/Streamly/Test/Common/Array.hs

@@ -190,9 +190,9 @@ testArraysOf =
 
 unsafeWriteIndex :: [Int] -> Int -> Int -> IO Bool
 unsafeWriteIndex xs i x = do
-    let arr = MA.fromList xs
-    arr1 <- MA.unsafeWriteIndex arr i x
-    x1 <- MA.unsafeIndexIO arr1 i
+    arr <- MA.fromListIO xs
+    MA.unsafeWriteIndex arr i x
+    x1 <- MA.unsafeIndexIO arr i
     return $ x1 == x
 
 lastN :: Int -> [a] -> [a]