X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=System%2FDirectory.hs;h=e5e988fa88222c7f0917c1e66f91b55bec3b0e94;hb=a70f356e023abdd0abb130cc149b0e3de7469044;hp=e3b3ed3fcd26f1b89db18b3c467a474182b064f7;hpb=79ce1f09530ec30a5da1d4b703413cad1948ca39;p=haskell-directory.git

diff --git a/System/Directory.hs b/System/Directory.hs
index e3b3ed3..e5e988f 100644
--- a/System/Directory.hs
+++ b/System/Directory.hs
@@ -507,7 +507,37 @@ 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 =
@@ -591,7 +621,7 @@ findExecutable binary =
               return (Just fpath)
       else return Nothing
 
-foreign import stdcall unsafe "SearchPath"
+foreign import stdcall unsafe "SearchPathA"
             c_SearchPath :: CString
                          -> CString
                          -> CString
@@ -599,6 +629,10 @@ foreign import stdcall unsafe "SearchPath"
                          -> CString
                          -> Ptr CString
                          -> IO CInt
+# if !defined(__GLASGOW_HASKELL__)
+long_path_size :: Int
+long_path_size = 4096
+# endif
 #else
  do
   path <- getEnv "PATH"