[#220] Avoid resource leaking in scanners

Problem: Currently we use lazy `readFile`, and xrefcheck opens all
the files immediately for reading, while file descriptors are
resource that can be finite.

Solution: Replaced lazy `readFile` with strict version.

src/Xrefcheck/Scanners/Markdown.hs

@@ -24,11 +24,10 @@ import CMarkGFM
 import Control.Lens (_Just, makeLenses, makeLensesFor, (.=))
 import Control.Monad.Trans.Writer.CPS (Writer, runWriter, tell)
 import Data.Aeson (FromJSON (..), genericParseJSON)
-import Data.ByteString.Lazy qualified as BSL
+import Data.ByteString qualified as BS
 import Data.DList qualified as DList
 import Data.Default (def)
 import Data.Text qualified as T
-import Data.Text.Lazy qualified as LT
 import Fmt (Buildable (..), nameF)
 import Text.HTML.TagSoup
 import Text.Interpolation.Nyan
@@ -406,16 +405,15 @@ textToMode ("ignore" : [x])
   | otherwise        = InvalidMode x
 textToMode _         = NotAnAnnotation
 
-parseFileInfo :: MarkdownConfig -> FilePath -> LT.Text -> (FileInfo, [ScanError])
+parseFileInfo :: MarkdownConfig -> FilePath -> T.Text -> (FileInfo, [ScanError])
 parseFileInfo config fp input
   = runWriter
   $ flip runReaderT config
   $ nodeExtractInfo fp
-  $ commonmarkToNode [optFootnotes] [extAutolink]
-  $ toStrict input
+  $ commonmarkToNode [optFootnotes] [extAutolink] input
 
 markdownScanner :: MarkdownConfig -> ScanAction
-markdownScanner config path = parseFileInfo config path . decodeUtf8 <$> BSL.readFile path
+markdownScanner config path = parseFileInfo config path . decodeUtf8 <$> BS.readFile path
 
 markdownSupport :: MarkdownConfig -> ([Extension], ScanAction)
 markdownSupport config = ([".md"], markdownScanner config)