import Hugs.Directory
#endif /* __HUGS__ */
+#if defined(__GLASGOW_HASKELL__) || defined(mingw32_HOST_OS)
+import Foreign
+import Foreign.C
+#endif
+
#ifdef __GLASGOW_HASKELL__
import Prelude
import System.Posix.Internals
import System.Time ( ClockTime(..) )
import System.IO
-import Foreign
-import Foreign.C
import GHC.IOBase ( IOException(..), IOErrorType(..), ioException )
{- |@'copyFile' old new@ copies the existing file from /old/ to /new/.
If the /new/ file already exists, it is atomically replaced by the /old/ file.
-Neither path may refer to an existing directory.
+Neither path may refer to an existing directory. The permissions of /old/ are
+copied to /new/, if possible.
+-}
+
+{- NOTES:
+
+It's tempting to try to remove the target file before opening it for
+writing. This could be useful: for example if the target file is an
+executable that is in use, writing will fail, but unlinking first
+would succeed.
+
+However, it certainly isn't always what you want.
+
+ * if the target file is hardlinked, removing it would break
+ the hard link, but just opening would preserve it.
+
+ * opening and truncating will preserve permissions and
+ ACLs on the target.
+
+ * If the destination file is read-only in a writable directory,
+ we might want copyFile to fail. Removing the target first
+ would succeed, however.
+
+ * If the destination file is special (eg. /dev/null), removing
+ it is probably not the right thing. Copying to /dev/null
+ should leave /dev/null intact, not replace it with a plain
+ file.
+
+ * There's a small race condition between removing the target and
+ opening it for writing during which time someone might
+ create it again.
-}
copyFile :: FilePath -> FilePath -> IO ()
copyFile fromFPath toFPath =
-- such executable. For example (findExecutable \"ghc\")
-- gives you the path to GHC.
findExecutable :: String -> IO (Maybe FilePath)
-findExecutable binary = do
+findExecutable binary =
+#if defined(mingw32_HOST_OS)
+ withCString binary $ \c_binary ->
+ withCString ('.':exeExtension) $ \c_ext ->
+ allocaBytes long_path_size $ \pOutPath ->
+ alloca $ \ppFilePart -> do
+ res <- c_SearchPath nullPtr c_binary c_ext (fromIntegral long_path_size) pOutPath ppFilePart
+ if res > 0 && res < fromIntegral long_path_size
+ then do fpath <- peekCString pOutPath
+ return (Just fpath)
+ else return Nothing
+
+foreign import stdcall unsafe "SearchPathA"
+ c_SearchPath :: CString
+ -> CString
+ -> CString
+ -> CInt
+ -> CString
+ -> Ptr CString
+ -> IO CInt
+# if !defined(__GLASGOW_HASKELL__)
+long_path_size :: Int
+long_path_size = 4096
+# endif
+#else
+ do
path <- getEnv "PATH"
search (parseSearchPath path)
where
b <- doesFileExist path
if b then return (Just path)
else search ds
+#endif
+
#ifdef __GLASGOW_HASKELL__
{- |@'getDirectoryContents' dir@ returns a list of /all/ entries