-----------------------------------------------------------------------------
---
+-- |
-- Module : System.Environment
-- Copyright : (c) The University of Glasgow 2001
--- License : BSD-style (see the file libraries/core/LICENSE)
+-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : provisional
-- Portability : portable
--
--- $Id: Environment.hs,v 1.1 2001/06/28 14:15:04 simonmar Exp $
---
-- Miscellaneous information about the system environment.
--
-----------------------------------------------------------------------------
module System.Environment
(
- , getArgs -- :: IO [String]
- , getProgName -- :: IO String
- , getEnv -- :: String -> IO String
+ getArgs, -- :: IO [String]
+ getProgName, -- :: IO String
+ getEnv, -- :: String -> IO String
+#ifdef __GLASGOW_HASKELL__
+ withArgs,
+ withProgName,
+#endif
) where
import Prelude
+import System.IO ( bracket )
+#ifdef __GLASGOW_HASKELL__
import Foreign
import Foreign.C
-
-#ifdef __GLASGOW_HASKELL__
+import Control.Monad
import GHC.IOBase
#endif
+#ifdef __HUGS__
+import Hugs.System
+#endif
+
+#ifdef __NHC__
+import System
+ ( getArgs
+ , getProgName
+ , getEnv
+ )
+#endif
+
-- ---------------------------------------------------------------------------
-- getArgs, getProgName, getEnv
-- Computation `getArgs' returns a list of the program's command
-- line arguments (not including the program name).
+#ifdef __GLASGOW_HASKELL__
getArgs :: IO [String]
-getArgs = do
- argv <- peek prog_argv_label
- argc <- peek prog_argc_label
- peekArray (fromIntegral argc - 1) (advancePtr argv 1) >>= mapM peekCString
+getArgs =
+ alloca $ \ p_argc ->
+ alloca $ \ p_argv -> do
+ getProgArgv p_argc p_argv
+ p <- fromIntegral `liftM` peek p_argc
+ argv <- peek p_argv
+ peekArray (p - 1) (advancePtr argv 1) >>= mapM peekCString
-foreign label "prog_argv" prog_argv_label :: Ptr (Ptr (Ptr CChar))
-foreign label "prog_argc" prog_argc_label :: Ptr CInt
+
+foreign import ccall unsafe "getProgArgv"
+ getProgArgv :: Ptr CInt -> Ptr (Ptr CString) -> IO ()
--- Computation `getProgName' returns the name of the program
--- as it was invoked.
+{-|
+Computation 'getProgName' returns the name of the program as it was
+invoked.
+However, this is hard-to-impossible to implement on some non-Unix
+OSes, so instead, for maximum portability, we just return the leafname
+of the program as invoked. Even then there are some differences
+between platforms: on Windows, for example, a program invoked as foo
+is probably really @FOO.EXE@, and that is what 'getProgName' will return.
+-}
getProgName :: IO String
-getProgName = do
- argv <- peek prog_argv_label
- unpackProgName argv
-
+getProgName =
+ alloca $ \ p_argc ->
+ alloca $ \ p_argv -> do
+ getProgArgv p_argc p_argv
+ argv <- peek p_argv
+ unpackProgName argv
+
unpackProgName :: Ptr (Ptr CChar) -> IO String -- argv[0]
unpackProgName argv = do
s <- peekElemOff argv 0 >>= peekCString
- return (de_slash "" s)
+ return (basename s)
where
- -- re-start accumulating at every '/'
- de_slash :: String -> String -> String
- de_slash acc [] = reverse acc
- de_slash _acc ('/':xs) = de_slash [] xs
- de_slash acc (x:xs) = de_slash (x:acc) xs
+ basename :: String -> String
+ basename f = go f f
+ where
+ go acc [] = acc
+ go acc (x:xs)
+ | isPathSeparator x = go xs xs
+ | otherwise = go acc xs
+
+ isPathSeparator :: Char -> Bool
+ isPathSeparator '/' = True
+#ifdef mingw32_TARGET_OS
+ isPathSeparator '\\' = True
+#endif
+ isPathSeparator _ = False
+
-- Computation `getEnv var' returns the value
-- of the environment variable {\em var}.
getEnv :: String -> IO String
getEnv name =
- withUnsafeCString name $ \s -> do
+ withCString name $ \s -> do
litstring <- c_getenv s
if litstring /= nullPtr
then peekCString litstring
else ioException (IOError Nothing NoSuchThing "getEnv"
"no environment variable" (Just name))
-foreign import ccall "getenv" unsafe
- c_getenv :: UnsafeCString -> IO (Ptr CChar)
+foreign import ccall unsafe "getenv"
+ c_getenv :: CString -> IO (Ptr CChar)
+
+{-|
+@withArgs args act@ - while executing action @act@, have 'System.getArgs'
+return @args@.
+-}
+withArgs xs act = do
+ p <- System.Environment.getProgName
+ withArgv (p:xs) act
+
+{-|
+@withProgName name act@ - while executing action @act@, have 'System.getProgName'return @name@.
+-}
+withProgName nm act = do
+ xs <- System.Environment.getArgs
+ withArgv (nm:xs) act
+
+-- Worker routine which marshals and replaces an argv vector for
+-- the duration of an action.
+
+withArgv new_args act = do
+ pName <- System.Environment.getProgName
+ existing_args <- System.Environment.getArgs
+ bracket (setArgs new_args)
+ (\argv -> do setArgs (pName:existing_args); freeArgv argv)
+ (const act)
+
+freeArgv :: Ptr CString -> IO ()
+freeArgv argv = do
+ size <- lengthArray0 nullPtr argv
+ sequence_ [peek (argv `advancePtr` i) >>= free | i <- [size, size-1 .. 0]]
+ free argv
+
+setArgs :: [String] -> IO (Ptr CString)
+setArgs argv = do
+ vs <- mapM newCString argv >>= newArray0 nullPtr
+ setArgsPrim (length argv) vs
+ return vs
+
+foreign import ccall unsafe "setProgArgv"
+ setArgsPrim :: Int -> Ptr CString -> IO ()
+#endif /* __GLASGOW_HASKELL__ */
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