Merge pull request haskell#35 from thomie/splitExtensions

Refactor and fix test for splitExtension(s)

System/FilePath/Internal.hs

@@ -202,7 +202,7 @@ getSearchPath = fmap splitSearchPath (getEnv "PATH")
 -- | Split on the extension. 'addExtension' is the inverse.
 --
 -- > uncurry (++) (splitExtension x) == x
--- > uncurry addExtension (splitExtension x) == x
+-- > Valid x => uncurry addExtension (splitExtension x) == x
 -- > splitExtension "file.txt" == ("file",".txt")
 -- > splitExtension "file" == ("file","")
 -- > splitExtension "file/file.txt" == ("file/file",".txt")
@@ -211,12 +211,12 @@ getSearchPath = fmap splitSearchPath (getEnv "PATH")
 -- > splitExtension "file/path.txt.bob.fred" == ("file/path.txt.bob",".fred")
 -- > splitExtension "file/path.txt/" == ("file/path.txt/","")
 splitExtension :: FilePath -> (String, String)
-splitExtension x = case d of
+splitExtension x = case nameDot of
                        "" -> (x,"")
-                       (y:ys) -> (a ++ reverse ys, y : reverse c)
+                       _ -> (dir ++ init nameDot, extSeparator : ext)
     where
-        (a,b) = splitFileName_ x
-        (c,d) = break isExtSeparator $ reverse b
+        (dir,file) = splitFileName_ x
+        (nameDot,ext) = breakEnd isExtSeparator file
 
 -- | Get the extension of a file, returns @\"\"@ for no extension, @.ext@ otherwise.
 --
@@ -274,7 +274,7 @@ hasExtension = any isExtSeparator . takeFileName
 -- | Split on all extensions
 --
 -- > uncurry (++) (splitExtensions x) == x
--- > uncurry addExtension (splitExtensions x) == x
+-- > Valid x => uncurry addExtension (splitExtensions x) == x
 -- > splitExtensions "file.tar.gz" == ("file",".tar.gz")
 splitExtensions :: FilePath -> (FilePath, String)
 splitExtensions x = (a ++ c, d)
@@ -444,10 +444,10 @@ splitFileName x = (if null dir then "./" else dir, name)
 -- look strange and upset simple equality properties.  See
 -- e.g. replaceFileName.
 splitFileName_ :: FilePath -> (String, String)
-splitFileName_ x = (c ++ reverse b, reverse a)
+splitFileName_ x = (drv ++ dir, file)
     where
-        (a,b) = break isPathSeparator $ reverse d
-        (c,d) = splitDrive x
+        (drv,pth) = splitDrive x
+        (dir,file) = breakEnd isPathSeparator pth
 
 -- | Set the filename.
 --
@@ -528,7 +528,7 @@ addTrailingPathSeparator x = if hasTrailingPathSeparator x then x else x ++ [pat
 dropTrailingPathSeparator :: FilePath -> FilePath
 dropTrailingPathSeparator x =
     if hasTrailingPathSeparator x && not (isDrive x)
-    then let x' = reverse $ dropWhile isPathSeparator $ reverse x
+    then let x' = dropWhileEnd isPathSeparator x
          in if null x' then [last x] else x'
     else x
 
@@ -807,7 +807,7 @@ isValid _ | isPosix = True
 isValid path =
         not (any (`elem` badCharacters) x2) &&
         not (any f $ splitDirectories x2) &&
-        not (length x1 >= 2 && all isPathSeparator x1) &&
+        not (isJust (readDriveShare x1) && all isPathSeparator x1) &&
         not (isJust (readDriveUNC x1) && not (hasTrailingPathSeparator x1))
     where
         (x1,x2) = splitDrive path
@@ -832,7 +832,7 @@ makeValid :: FilePath -> FilePath
 makeValid "" = "_"
 makeValid path
         | isPosix = path
-        | length drv >= 2 && all isPathSeparator drv = take 2 drv ++ "drive"
+        | isJust (readDriveShare drv) && all isPathSeparator drv = take 2 drv ++ "drive"
         | isJust (readDriveUNC drv) && not (hasTrailingPathSeparator drv) =
             makeValid (drv ++ [pathSeparator] ++ pth)
         | otherwise = joinDrive drv $ validElements $ validChars pth
@@ -891,3 +891,22 @@ isRelativeDrive x =
 -- > isAbsolute x == not (isRelative x)
 isAbsolute :: FilePath -> Bool
 isAbsolute = not . isRelative
+
+
+-----------------------------------------------------------------------------
+-- dropWhileEnd (>2) [1,2,3,4,1,2,3,4] == [1,2,3,4,1,2])
+-- Note that Data.List.dropWhileEnd is only available in base >= 4.5.
+dropWhileEnd :: (a -> Bool) -> [a] -> [a]
+dropWhileEnd p = reverse . dropWhile p . reverse
+
+-- takeWhileEnd (>2) [1,2,3,4,1,2,3,4] == [3,4])
+takeWhileEnd :: (a -> Bool) -> [a] -> [a]
+takeWhileEnd p = reverse . takeWhile p . reverse
+
+-- spanEnd (>2) [1,2,3,4,1,2,3,4] = ([1,2,3,4,1,2], [3,4])
+spanEnd :: (a -> Bool) -> [a] -> ([a], [a])
+spanEnd p xs = (dropWhileEnd p xs, takeWhileEnd p xs)
+
+-- breakEnd (< 2) [1,2,3,4,1,2,3,4] == ([1,2,3,4,1],[2,3,4])
+breakEnd :: (a -> Bool) -> [a] -> ([a], [a])
+breakEnd p = spanEnd (not . p)

tests/TestGen.hs

@@ -536,9 +536,9 @@ block11 = do
  putStrLn "Test 253, from line 204"
  test (\ (QFilePath x) -> (uncurry ( ++ ) ( P.splitExtension x ) == x))
  putStrLn "Test 254, from line 205"
- test (\ (QFilePath x) -> (uncurry W.addExtension ( W.splitExtension x ) == x))
+ test (\ (QFilePath x) -> ((\ x -> uncurry W.addExtension ( W.splitExtension x ) == x ) ( W.makeValid x )))
  putStrLn "Test 255, from line 205"
- test (\ (QFilePath x) -> (uncurry P.addExtension ( P.splitExtension x ) == x))
+ test (\ (QFilePath x) -> ((\ x -> uncurry P.addExtension ( P.splitExtension x ) == x ) ( P.makeValid x )))
  putStrLn "Test 256, from line 223"
  test (\ (QFilePath x) -> (W.takeExtension x == snd ( W.splitExtension x )))
  putStrLn "Test 257, from line 223"
@@ -568,9 +568,9 @@ block11 = do
  putStrLn "Test 269, from line 276"
  test (\ (QFilePath x) -> (uncurry ( ++ ) ( P.splitExtensions x ) == x))
  putStrLn "Test 270, from line 277"
- test (\ (QFilePath x) -> (uncurry W.addExtension ( W.splitExtensions x ) == x))
+ test (\ (QFilePath x) -> ((\ x -> uncurry W.addExtension ( W.splitExtensions x ) == x ) ( W.makeValid x )))
  putStrLn "Test 271, from line 277"
- test (\ (QFilePath x) -> (uncurry P.addExtension ( P.splitExtensions x ) == x))
+ test (\ (QFilePath x) -> ((\ x -> uncurry P.addExtension ( P.splitExtensions x ) == x ) ( P.makeValid x )))
  putStrLn "Test 272, from line 287"
  test (\ (QFilePath x) -> (not $ W.hasExtension ( W.dropExtensions x )))
  putStrLn "Test 273, from line 287"