Add getDirectoryContents' which ignores "." and ".."

System/Directory.hs

@@ -30,6 +30,7 @@ module System.Directory
     , removeDirectoryRecursive
     , renameDirectory
     , getDirectoryContents
+    , getDirectoryContentsA
     -- ** Current working directory
     , getCurrentDirectory
     , setCurrentDirectory
@@ -571,8 +572,8 @@ removePathRecursive path =
 removeContentsRecursive :: FilePath -> IO ()
 removeContentsRecursive path =
   (`ioeSetLocation` "removeContentsRecursive") `modifyIOError` do
-    cont <- getDirectoryContents path
-    mapM_ removePathRecursive [path </> x | x <- cont, x /= "." && x /= ".."]
+    cont <- getDirectoryContentsA path
+    mapM_ removePathRecursive [path </> x | x <- cont]
     removeDirectory path
 
 #if __GLASGOW_HASKELL__
@@ -1030,6 +1031,15 @@ getDirectoryContents path =
                  -- no need to reverse, ordering is undefined
 #endif /* mingw32 */
 
+{- | A version of 'getDirectoryContents' which returns /almost all/
+entries, ignoring the current and parent directories, @.@ and @..@.
+
+-}
+getDirectoryContentsA :: FilePath -> IO [FilePath]
+getDirectoryContentsA path =
+  (filter f) <$> (getDirectoryContents path)
+  where f filename = filename /= "." && filename /= ".."
+
 #endif /* __GLASGOW_HASKELL__ */
 
 

tests/CopyFile001.hs

@@ -3,19 +3,17 @@ module CopyFile001 where
 #include "util.inl"
 import System.Directory
 import Data.List (sort)
-import Data.Monoid ((<>))
 import System.FilePath ((</>))
 
 main :: TestEnv -> IO ()
 main _t = do
   createDirectory dir
   writeFile (dir </> from) contents
-  T(expectEq) () (specials <> [from]) . sort =<< getDirectoryContents dir
+  T(expectEq) () [from] . sort =<< getDirectoryContentsA dir
   copyFile (dir </> from) (dir </> to)
-  T(expectEq) () (specials <> [from, to]) . sort =<< getDirectoryContents dir
+  T(expectEq) () [from, to] . sort =<< getDirectoryContentsA dir
   T(expectEq) () contents =<< readFile (dir </> to)
   where
-    specials = [".", ".."]
     contents = "This is the data\n"
     from     = "source"
     to       = "target"

tests/CopyFile002.hs

@@ -3,19 +3,17 @@ module CopyFile002 where
 #include "util.inl"
 import System.Directory
 import Data.List (sort)
-import Data.Monoid ((<>))
 
 main :: TestEnv -> IO ()
 main _t = do
   -- Similar to CopyFile001 but moves a file in the current directory
   -- (Bug #1652 on GHC Trac)
   writeFile from contents
-  T(expectEq) () (specials <> [from]) . sort =<< getDirectoryContents "."
+  T(expectEq) () [from] . sort =<< getDirectoryContentsA "."
   copyFile from to
-  T(expectEq) () (specials <> [from, to]) . sort =<< getDirectoryContents "."
+  T(expectEq) () [from, to] . sort =<< getDirectoryContentsA "."
   T(expectEq) () contents =<< readFile to
   where
-    specials = [".", ".."]
     contents = "This is the data\n"
     from     = "source"
     to       = "target"

tests/GetDirContents001.hs

@@ -10,11 +10,10 @@ import System.FilePath  ((</>))
 main :: TestEnv -> IO ()
 main _t = do
   createDirectory dir
-  T(expectEq) () specials . sort =<< getDirectoryContents dir
+  T(expectEq) () [] . sort =<< getDirectoryContentsA dir
   names <- for [1 .. 100 :: Int] $ \ i -> do
     let name = 'f' : show i
     writeFile (dir </> name) ""
     return name
-  T(expectEq) () (sort (specials <> names)) . sort =<< getDirectoryContents dir
+  T(expectEq) () (sort names) . sort =<< getDirectoryContentsA dir
   where dir      = "dir"
-        specials = [".", ".."]

tests/TestUtils.hs

@@ -41,10 +41,10 @@ copyPathRecursive source dest =
     dirExists <- doesDirectoryExist source
     if dirExists
       then do
-        contents <- getDirectoryContents source
+        contents <- getDirectoryContentsA source
         createDirectory dest
         mapM_ (uncurry copyPathRecursive)
-          [(source </> x, dest </> x) | x <- contents, x /= "." && x /= ".."]
+          [(source </> x, dest </> x) | x <- contents]
       else copyFile source dest
 
 modifyPermissions :: FilePath -> (Permissions -> Permissions) -> IO ()

tests/WithCurrentDirectory.hs

@@ -10,17 +10,16 @@ main :: TestEnv -> IO ()
 main _t = do
   createDirectory dir
   -- Make sure we're starting empty
-  T(expectEq) () specials . sort =<< getDirectoryContents dir
+  T(expectEq) () [] . sort =<< getDirectoryContentsA dir
   cwd <- getCurrentDirectory
   withCurrentDirectory dir (writeFile testfile contents)
   -- Are we still in original directory?
   T(expectEq) () cwd =<< getCurrentDirectory
   -- Did the test file get created?
-  T(expectEq) () (specials <> [testfile]) . sort =<< getDirectoryContents dir
+  T(expectEq) () [testfile] . sort =<< getDirectoryContentsA dir
   -- Does the file contain what we expected to write?
   T(expectEq) () contents =<< readFile (dir </> testfile)
   where
     testfile = "testfile"
     contents = "some data\n"
     dir = "dir"
-    specials = [".", ".."]