better readProcess

Annex/UUID.hs

@@ -32,7 +32,7 @@ configkey = annexConfig "uuid"
 {- Generates a UUID. There is a library for this, but it's not packaged,
  - so use the command line tool. -}
 genUUID :: IO UUID
-genUUID = gen . lines <$> readProcess command params []
+genUUID = gen . lines <$> readProcess command params
 	where
 		gen [] = error $ "no output from " ++ command
 		gen (l:_) = toUUID l

Backend/SHA.hs

@@ -54,7 +54,7 @@ shaN shasize file filesize = do
 	case shaCommand shasize filesize of
 		Left sha -> liftIO $ sha <$> L.readFile file
 		Right command -> liftIO $ parse command . lines <$>
-			readProcess command (toCommand [File file]) ""
+			readProcess command (toCommand [File file])
 	where
 		parse command [] = bad command
 		parse command (l:_)

Config.hs

@@ -56,7 +56,7 @@ remoteCost r def = do
 	cmd <- getRemoteConfig r "cost-command" ""
 	(fromMaybe def . readish) <$>
 		if not $ null cmd
-			then liftIO $ readProcess "sh" ["-c", cmd] ""
+			then liftIO $ readProcess "sh" ["-c", cmd]
 			else getRemoteConfig r "cost" ""
 
 cheapRemoteCost :: Int
@@ -116,4 +116,4 @@ getHttpHeaders = do
 	cmd <- getConfig (annexConfig "http-headers-command") ""
 	if null cmd
 		then fromRepo $ Git.Config.getList "annex.http-headers"
-		else lines <$> liftIO (readProcess "sh" ["-c", cmd] "")
+		else lines <$> liftIO (readProcess "sh" ["-c", cmd])

Git/Command.hs

@@ -52,7 +52,7 @@ pipeRead params repo = assertLocal repo $
  - strictly. -}
 pipeWriteRead :: [CommandParam] -> String -> Repo -> IO String
 pipeWriteRead params s repo = assertLocal repo $
-	readProcess "git" (toCommand $ gitCommandLine params repo) s
+	writeReadProcess "git" (toCommand $ gitCommandLine params repo) s
 
 {- Reads null terminated output of a git command (as enabled by the -z 
  - parameter), and splits it. -}

Utility/INotify.hs

@@ -160,7 +160,7 @@ tooManyWatches hook dir = do
 
 querySysctl :: Read a => [CommandParam] -> IO (Maybe a)
 querySysctl ps = do
-	v <- catchMaybeIO $ readProcess "sysctl" (toCommand ps) []
+	v <- catchMaybeIO $ readProcess "sysctl" (toCommand ps)
 	case v of
 		Nothing -> return Nothing
 		Just s -> return $ parsesysctl s

Utility/Process.hs

@@ -22,6 +22,7 @@ module Utility.Process (
 	withBothHandles,
 	createProcess,
 	runInteractiveProcess,
+	writeReadProcess,
 	readProcess
 ) where
 
@@ -192,11 +193,22 @@ runInteractiveProcess f args c e = do
 			}
 	System.Process.runInteractiveProcess f args c e
 
-readProcess
+{- I think this is a more descriptive name than System.Process.readProcess. -}
+writeReadProcess
 	:: FilePath	
 	-> [String]	
 	-> String	
 	-> IO String
-readProcess f args input = do
+writeReadProcess f args input = do
-	debugProcess $ (proc f args) { std_out = CreatePipe }
+	debugProcess $ (proc f args) { std_out = CreatePipe, std_in = CreatePipe }
 	System.Process.readProcess f args input
+
+{- Normally, when reading from a process, it does not need to be fed any
+ - input. -}
+readProcess
+	:: FilePath	
+	-> [String]	
+	-> IO String
+readProcess f args = do
+	debugProcess $ (proc f args) { std_out = CreatePipe }
+	System.Process.readProcess f args []