+#endif
+
+-- | 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
+-- path. Note that it is impossible to guarantee that the
+-- implication (same file\/dir <=> same canonicalizedPath) holds
+-- in either direction: this function can make only a best-effort
+-- attempt.
+canonicalizePath :: FilePath -> IO FilePath
+canonicalizePath fpath =
+ withCString fpath $ \pInPath ->
+ allocaBytes long_path_size $ \pOutPath ->
+#if defined(mingw32_TARGET_OS)
+ alloca $ \ppFilePart ->
+ do c_GetFullPathName pInPath (fromIntegral long_path_size) pOutPath ppFilePart
+#else
+ do c_realpath pInPath pOutPath
+#endif
+ peekCString pOutPath
+
+#if defined(mingw32_TARGET_OS)
+foreign import stdcall unsafe "GetFullPathName"
+ c_GetFullPathName :: CString
+ -> CInt
+ -> CString
+ -> Ptr CString
+ -> IO CInt
+#else
+foreign import ccall unsafe "realpath"
+ c_realpath :: CString
+ -> CString
+ -> IO CString
+#endif
+
+-- | Given an executable file name, searches for such file
+-- in the directories listed in system PATH. The returned value
+-- is the path to the found executable or Nothing if there isn't
+-- such executable. For example (findExecutable \"ghc\")
+-- gives you the path to GHC.
+findExecutable :: String -> IO (Maybe FilePath)
+findExecutable binary = do
+ path <- getEnv "PATH"
+ search (parseSearchPath path)
+ where
+#ifdef mingw32_TARGET_OS
+ fileName = binary `joinFileExt` "exe"
+#else
+ fileName = binary
+#endif
+
+ search :: [FilePath] -> IO (Maybe FilePath)
+ search [] = return Nothing
+ search (d:ds) = do
+ let path = d `joinFileName` fileName
+ b <- doesFileExist path
+ if b then return (Just path)
+ else search ds