X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=System%2FDirectory.hs;h=beed8798cca5fa154974083563baaaf4055361f4;hb=30c6a57ac9dfc3808a28bb2654912aa7460568c8;hp=5e87c213b6749fe9c131e401113024dd28819562;hpb=6914d7de311fa3c49dc2a9a26c4eae927164b2f0;p=haskell-directory.git

diff --git a/System/Directory.hs b/System/Directory.hs
index 5e87c21..beed879 100644
--- a/System/Directory.hs
+++ b/System/Directory.hs
@@ -39,6 +39,7 @@ module System.Directory
     , copyFile                  -- :: FilePath -> FilePath -> IO ()
     
     , canonicalizePath
+    , makeRelativeToCurrentDirectory
     , findExecutable
 
     -- * Existence tests
@@ -67,22 +68,22 @@ module System.Directory
 
 import System.Directory.Internals
 import System.Environment      ( getEnv )
+import System.FilePath
 import System.IO.Error
 import Control.Monad           ( when, unless )
 
 #ifdef __NHC__
 import Directory
-import NHC.FFI
 #endif /* __NHC__ */
 
 #ifdef __HUGS__
 import Hugs.Directory
 #endif /* __HUGS__ */
 
-#if defined(__GLASGOW_HASKELL__) || defined(mingw32_HOST_OS)
 import Foreign
 import Foreign.C
-#endif
+
+{-# CFILES cbits/directory.c #-}
 
 #ifdef __GLASGOW_HASKELL__
 import Prelude
@@ -507,26 +508,47 @@ renameFile opath npath =
 
 {- |@'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 = do
-	-- We try removing the target file before opening it for
-	-- writing.  In the event that the target file is locked or in
-	-- use, this allows us to replace it safely.  However, it
-	-- leaves a race condition: someone else might create the file
-	-- after we delete it, but there isn't much we can do about
-	-- that.
+copyFile fromFPath toFPath =
 #if (!(defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ > 600))
-	contents <- readFile fromFPath
-	try (removeFile toFPath)
-	writeFile toFPath contents
-	try (copyPermissions fromFPath toFPath)
-	return ()
+	do readFile fromFPath >>= writeFile toFPath
+	   try (copyPermissions fromFPath toFPath)
+	   return ()
 #else
-	(bracket (openBinaryFile fromFPath ReadMode) hClose $ \hFrom -> do
-	 try (removeFile toFPath)
-	 bracket (openBinaryFile toFPath WriteMode) hClose $ \hTo -> do
+	(bracket (openBinaryFile fromFPath ReadMode) hClose $ \hFrom ->
+	 bracket (openBinaryFile toFPath WriteMode) hClose $ \hTo ->
 	 allocaBytes bufferSize $ \buffer -> do
 		copyContents hFrom hTo buffer
 		try (copyPermissions fromFPath toFPath)
@@ -543,7 +565,6 @@ copyFile fromFPath toFPath = do
 				copyContents hFrom hTo buffer
 #endif
 
-#ifdef __GLASGOW_HASKELL__
 -- | Given path referring to a file or directory, returns a
 -- canonicalized path, with the intent that two paths referring
 -- to the same file\/directory will map to the same canonicalized
@@ -576,11 +597,12 @@ foreign import ccall unsafe "realpath"
                               -> CString
                               -> IO CString
 #endif
-#else /* !__GLASGOW_HASKELL__ */
--- dummy implementation
-canonicalizePath :: FilePath -> IO FilePath
-canonicalizePath fpath = return fpath
-#endif /* !__GLASGOW_HASKELL__ */
+
+-- | 'makeRelative' the current directory.
+makeRelativeToCurrentDirectory :: FilePath -> IO FilePath
+makeRelativeToCurrentDirectory x = do
+    cur <- getCurrentDirectory
+    return $ makeRelative cur x
 
 -- | Given an executable file name, searches for such file
 -- in the directories listed in system PATH. The returned value 
@@ -608,10 +630,6 @@ foreign import stdcall unsafe "SearchPathA"
                          -> CString
                          -> Ptr CString
                          -> IO CInt
-# if !defined(__GLASGOW_HASKELL__)
-long_path_size :: Int
-long_path_size = 4096
-# endif
 #else
  do
   path <- getEnv "PATH"
@@ -852,17 +870,21 @@ fileNameEndClean name =
       i  = (length name) - 1
       ec = name !! i
 
-foreign import ccall unsafe "__hscore_long_path_size"
-  long_path_size :: Int
-
-foreign import ccall unsafe "__hscore_R_OK" r_OK :: CMode
-foreign import ccall unsafe "__hscore_W_OK" w_OK :: CMode
-foreign import ccall unsafe "__hscore_X_OK" x_OK :: CMode
+foreign import ccall unsafe "__hscore_R_OK" r_OK :: CInt
+foreign import ccall unsafe "__hscore_W_OK" w_OK :: CInt
+foreign import ccall unsafe "__hscore_X_OK" x_OK :: CInt
 
 foreign import ccall unsafe "__hscore_S_IRUSR" s_IRUSR :: CMode
 foreign import ccall unsafe "__hscore_S_IWUSR" s_IWUSR :: CMode
 foreign import ccall unsafe "__hscore_S_IXUSR" s_IXUSR :: CMode
 
+foreign import ccall unsafe "__hscore_long_path_size"
+  long_path_size :: Int
+
+#else
+long_path_size :: Int
+long_path_size = 2048	--  // guess?
+
 #endif /* __GLASGOW_HASKELL__ */
 
 {- | Returns the current user's home directory.
@@ -888,7 +910,7 @@ cannot be found.
 -}
 getHomeDirectory :: IO FilePath
 getHomeDirectory =
-#if __GLASGOW_HASKELL__ && defined(mingw32_HOST_OS)
+#if defined(mingw32_HOST_OS)
   allocaBytes long_path_size $ \pPath -> do
      r <- c_SHGetFolderPath nullPtr csidl_PROFILE nullPtr 0 pPath
      if (r < 0)
@@ -930,7 +952,7 @@ cannot be found.
 -}
 getAppUserDataDirectory :: String -> IO FilePath
 getAppUserDataDirectory appName = do
-#if __GLASGOW_HASKELL__ && defined(mingw32_HOST_OS)
+#if defined(mingw32_HOST_OS)
   allocaBytes long_path_size $ \pPath -> do
      r <- c_SHGetFolderPath nullPtr csidl_APPDATA nullPtr 0 pPath
      when (r<0) (raiseUnsupported "System.Directory.getAppUserDataDirectory")
@@ -964,7 +986,7 @@ cannot be found.
 -}
 getUserDocumentsDirectory :: IO FilePath
 getUserDocumentsDirectory = do
-#if __GLASGOW_HASKELL__ && defined(mingw32_HOST_OS)
+#if defined(mingw32_HOST_OS)
   allocaBytes long_path_size $ \pPath -> do
      r <- c_SHGetFolderPath nullPtr csidl_PERSONAL nullPtr 0 pPath
      when (r<0) (raiseUnsupported "System.Directory.getUserDocumentsDirectory")
@@ -1001,7 +1023,7 @@ The function doesn\'t verify whether the path exists.
 -}
 getTemporaryDirectory :: IO FilePath
 getTemporaryDirectory = do
-#if __GLASGOW_HASKELL__ && defined(mingw32_HOST_OS)
+#if defined(mingw32_HOST_OS)
   allocaBytes long_path_size $ \pPath -> do
      r <- c_GetTempPath (fromIntegral long_path_size) pPath
      peekCString pPath
@@ -1009,7 +1031,7 @@ getTemporaryDirectory = do
   catch (getEnv "TMPDIR") (\ex -> return "/tmp")
 #endif
 
-#if __GLASGOW_HASKELL__ && defined(mingw32_HOST_OS)
+#if defined(mingw32_HOST_OS)
 foreign import ccall unsafe "__hscore_getFolderPath"
             c_SHGetFolderPath :: Ptr () 
                               -> CInt