module Directory (getDirectoryContents) where

import NHC.GreenCard
import PatchIOError

%-#include <dirent.h>

newtype Dir = Dir ForeignObj
%dis dir x = Dir (declare "DIR*" x in foreign "hs_closedir" x)

%fun closedir :: Dir -> IO Int
%call (dir d)
%code
%  if (d==NULL) err=0; else err=closedir(d);
%result (int err)

%fun opendir :: FilePath -> IO (Int,Dir)
%call (filePath fp)
%code
%  d = opendir(fp);
%  if (d==NULL) err=-1; else err=0;
%result (int err, dir d)

%fun readdir :: Dir -> IO (Int,FilePath)
%call (dir d)
%code
%  struct dirent *e;
%  e = readdir(d);
%  if (e==NULL) {
%     err=-1;
%     fp="";
%  } else {
%    err=0;
%    fp=e->d_name;
%  }
%result (int err, filePath fp)

getDirectoryContents :: FilePath -> IO [FilePath]
getDirectoryContents fp = do
  d <- patchIOErrorFVal "getDirectoryContents" fp opendir
  lazyDirContents d

-- Despite the name, I'm not entirely sure that this really is lazy.
lazyDirContents :: Dir -> IO [FilePath]
lazyDirContents d =
  catch (do f  <- patchIOErrorVal "readDir" (readdir d)
            fs <- lazyDirContents d
            return (f:fs))
        (\e-> do -- patchIOError "closeDir" (closedir d)
                 return [])
  

{-------
newtype DirEntry = DirEntry ()
foreign import opendir  :: CString -> IO Addr
foreign import closedir :: Addr -> IO Int
foreign import readdir  :: Dir -> IO Ptr
-}