[project @ 2005-11-17 11:28:43 by simonmar]

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

diff --git a/System/Process.hs b/System/Process.hs
index d4bc43f..91a9359 100644 (file)
--- a/System/Process.hs
+++ b/System/Process.hs
@@ -237,11 +237,23 @@ waitForProcess
   :: ProcessHandle
   -> IO ExitCode
 waitForProcess ph = do
-  handle <- getProcessHandle ph
-  code <- throwErrnoIfMinus1 "waitForProcess" (c_waitForProcess handle)
-  if (code == 0) 
-    then return ExitSuccess
-    else return (ExitFailure (fromIntegral code))
+  p_ <- withProcessHandle ph $ \p_ -> return (p_,p_)
+  case p_ of
+    ClosedHandle e -> return e
+    OpenHandle h  -> do
+       -- don't hold the MVar while we call c_waitForProcess...
+       -- (XXX but there's a small race window here during which another
+       -- thread could close the handle or call waitForProcess)
+       code <- throwErrnoIfMinus1 "waitForProcess" (c_waitForProcess h)
+       withProcessHandle ph $ \p_ ->
+         case p_ of
+           ClosedHandle e -> return (p_,e)
+           OpenHandle ph  -> do
+             closePHANDLE ph
+             let e = if (code == 0)
+                  then ExitSuccess
+                  else (ExitFailure (fromIntegral code))
+             return (ClosedHandle e, e)
 
 -- ----------------------------------------------------------------------------
 -- terminateProcess
@@ -256,8 +268,14 @@ waitForProcess ph = do
 -- an exit code of 1.
 terminateProcess :: ProcessHandle -> IO ()
 terminateProcess ph = do
-  pid <- getProcessHandle ph
-  throwErrnoIfMinus1_ "terminateProcess" (c_terminateProcess pid)
+  withProcessHandle_ ph $ \p_ ->
+    case p_ of 
+      ClosedHandle _ -> return p_
+      OpenHandle h -> do
+       throwErrnoIfMinus1_ "terminateProcess" $ c_terminateProcess h
+       return p_
+       -- does not close the handle, we might want to try terminating it
+       -- again, or get its exit code.
 
 -- ----------------------------------------------------------------------------
 -- getProcessExitCode
@@ -271,15 +289,21 @@ Subsequent calls to @getProcessExitStatus@ always return @'Just'
 -}
 getProcessExitCode :: ProcessHandle -> IO (Maybe ExitCode)
 getProcessExitCode ph = do
-  handle <- getProcessHandle ph
-  alloca $ \pExitCode -> do
-    res <- throwErrnoIfMinus1 "getProcessExitCode" (c_getProcessExitCode handle pExitCode)
-    code <- peek pExitCode
-    if res == 0
-      then return Nothing
-      else if code == 0
-             then return (Just ExitSuccess)
-             else return (Just (ExitFailure (fromIntegral code)))
+  withProcessHandle ph $ \p_ ->
+    case p_ of
+      ClosedHandle e -> return (p_, Just e)
+      OpenHandle h ->
+       alloca $ \pExitCode -> do
+           res <- throwErrnoIfMinus1 "getProcessExitCode" $
+                       c_getProcessExitCode h pExitCode
+           code <- peek pExitCode
+           if res == 0
+             then return (p_, Nothing)
+             else do
+                  closePHANDLE h
+                  let e  | code == 0 = ExitSuccess
+                         | otherwise = ExitFailure (fromIntegral code)
+                  return (ClosedHandle e, Just e)
 
 -- ----------------------------------------------------------------------------
 -- Interface to C bits