[project @ 2005-07-23 17:08:03 by ross]

[haskell-directory.git] / System / Cmd.hs

diff --git a/System/Cmd.hs b/System/Cmd.hs
index ceb0bbe..730b0ca 100644 (file)
--- a/System/Cmd.hs
+++ b/System/Cmd.hs
@@ -14,17 +14,20 @@
 
 module System.Cmd
     ( system,        -- :: String -> IO ExitCode
-#ifdef __GLASGOW_HASKELL__
       rawSystem,     -- :: FilePath -> [String] -> IO ExitCode
-#endif
     ) where
 
 import Prelude
 
+import System.Exit     ( ExitCode )
+
 #ifdef __GLASGOW_HASKELL__
 import System.Process
-import System.Exit     ( ExitCode )
 import GHC.IOBase      ( ioException, IOException(..), IOErrorType(..) )
+#if !defined(mingw32_HOST_OS)
+import System.Process.Internals
+import System.Posix.Signals
+#endif
 #endif
 
 #ifdef __HUGS__
@@ -61,12 +64,81 @@ passes the command to the Windows command interpreter (@CMD.EXE@ or
 #ifdef __GLASGOW_HASKELL__
 system :: String -> IO ExitCode
 system "" = ioException (IOError Nothing InvalidArgument "system" "null command" Nothing)
-system cmd = do
-  p <- runCommand cmd
+system str = do
+#if mingw32_HOST_OS
+  p <- runCommand str
   waitForProcess p
+#else
+  -- The POSIX version of system needs to do some manipulation of signal
+  -- handlers.  Since we're going to be synchronously waiting for the child,
+  -- we want to ignore ^C in the parent, but handle it the default way
+  -- in the child (using SIG_DFL isn't really correct, it should be the
+  -- original signal handler, but the GHC RTS will have already set up
+  -- its own handler and we don't want to use that).
+  old_int  <- installHandler sigINT  Ignore Nothing
+  old_quit <- installHandler sigQUIT Ignore Nothing
+  (cmd,args) <- commandToProcess str
+  p <- runProcessPosix "runCommand" cmd args Nothing Nothing 
+               Nothing Nothing Nothing
+               (Just defaultSignal) (Just defaultSignal)
+  r <- waitForProcess p
+  installHandler sigINT  old_int Nothing
+  installHandler sigQUIT old_quit Nothing
+  return r
+#endif  /* mingw32_HOST_OS */
+#endif  /* __GLASGOW_HASKELL__ */
 
+{-|
+The computation @'rawSystem' cmd args@ runs the operating system command
+@cmd@ in such a way that it receives as arguments the @args@ strings
+exactly as given, with no funny escaping or shell meta-syntax expansion.
+It will therefore behave more portably between operating systems than 'system'.
+
+The return codes and possible failures are the same as for 'system'.
+-}
 rawSystem :: String -> [String] -> IO ExitCode
+#ifdef __GLASGOW_HASKELL__
 rawSystem cmd args = do
+
+#if mingw32_HOST_OS
   p <- runProcess cmd args Nothing Nothing Nothing Nothing Nothing
   waitForProcess p
-#endif  /* __GLASGOW_HASKELL__ */
+#else
+  old_int  <- installHandler sigINT  Ignore Nothing
+  old_quit <- installHandler sigQUIT Ignore Nothing
+  p <- runProcessPosix "rawSystem" cmd args Nothing Nothing 
+               Nothing Nothing Nothing
+               (Just defaultSignal) (Just defaultSignal)
+  r <- waitForProcess p
+  installHandler sigINT  old_int Nothing
+  installHandler sigQUIT old_quit Nothing
+  return r
+#endif
+
+#elif !mingw32_HOST_OS
+-- crude fallback implementation: could do much better than this under Unix
+rawSystem cmd args = system (unwords (map translate (cmd:args)))
+
+translate :: String -> String
+translate str = '\'' : foldr escape "'" str
+  where        escape '\'' = showString "'\\''"
+       escape c    = showChar c
+#elif __HUGS__
+rawSystem cmd args = system (unwords (cmd : map translate args))
+
+translate :: String -> String
+translate str = '"' : foldr escape "\"" str
+  where        escape '"'  = showString "\\\""
+       escape '\\' = showString "\\\\"
+       escape c    = showChar c
+#else /* mingw32_HOST_OS &&  ! __GLASGOW_HASKELL__ && ! __HUGS__ */
+rawSystem cmd args = system (unwords (map translate (cmd:args)))
+
+-- copied from System.Process (qv)
+translate :: String -> String
+translate str = '"' : snd (foldr escape (True,"\"") str)
+  where        escape '"'  (b,     str) = (True,  '\\' : '"'  : str)
+       escape '\\' (True,  str) = (True,  '\\' : '\\' : str)
+       escape '\\' (False, str) = (False, '\\' : str)
+       escape c    (b,     str) = (False, c : str)
+#endif