ghc-mod/Language/Haskell/GhcMod/Output.hs

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-- ghc-mod: Making Haskell development *more* fun
-- Copyright (C) 2015 Daniel Gröber <dxld ÄT darkboxed DOT org>
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU Affero General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU Affero General Public License for more details.
--
-- You should have received a copy of the GNU Affero General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
-- Derived from process:System.Process
-- Copyright (c) The University of Glasgow 2004-2008
module Language.Haskell.GhcMod.Output (
gmPutStr
, gmErrStr
, gmPutStrLn
, gmErrStrLn
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, gmUnsafePutStrLn
, gmUnsafeErrStrLn
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, gmReadProcess
, stdoutGateway
) where
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import Data.List
import System.IO
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import System.Exit
import System.Process
import Control.Monad
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import Control.DeepSeq
import Control.Exception
import Control.Concurrent
import Language.Haskell.GhcMod.Types hiding (LineSeparator)
import Language.Haskell.GhcMod.Monad.Types
withLines :: (String -> String) -> String -> String
withLines f s = let
res = unlines $ map f $ lines s
in
case s of
[] -> res
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_ | not $ isTerminated s ->
reverse $ drop 1 $ reverse res
_ -> res
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isTerminated :: String -> Bool
isTerminated "" = False
isTerminated s = isNewline (last s)
isNewline :: Char -> Bool
isNewline c = c == '\n'
toGmLines :: String -> (GmLines String)
toGmLines "" = GmLines GmPartial ""
toGmLines s | isNewline (last s) = GmLines GmTerminated s
toGmLines s = GmLines GmPartial s
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outputFns :: (GmEnv m, MonadIO m')
=> m (GmLines String -> m' (), GmLines String -> m' ())
outputFns = do
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opts <- options
env <- gmeAsk
return $ outputFns' opts (gmOutput env)
outputFns' :: MonadIO m'
=> Options
-> GmOutput
-> (GmLines String -> m' (), GmLines String -> m' ())
outputFns' opts output = let
Options {..} = opts
pfx f = withLines f
outPfx, errPfx :: GmLines String -> GmLines String
(outPfx, errPfx) =
case linePrefix of
Nothing -> ( id, id )
Just (op, ep) -> ( fmap $ pfx (op++), fmap $ pfx (ep++) )
in
case output of
GmOutputStdio ->
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( liftIO . putStr . unGmLine . outPfx
, liftIO . hPutStr stderr . unGmLine . errPfx)
GmOutputChan c ->
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( liftIO . writeChan c . (,) GmOut . outPfx
, liftIO . writeChan c . (,) GmErr .errPfx)
gmPutStr, gmPutStrLn, gmErrStr, gmErrStrLn
:: (MonadIO m, GmEnv m) => String -> m ()
gmPutStr str = do
putOut <- fst `liftM` outputFns
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putOut $ toGmLines str
gmPutStrLn = gmPutStr . (++"\n")
gmErrStrLn = gmErrStr . (++"\n")
gmErrStr str = do
putErr <- snd `liftM` outputFns
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putErr $ toGmLines str
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-- | Only use these when you're sure there are no other writers on stdout
gmUnsafePutStrLn, gmUnsafeErrStrLn
:: MonadIO m => Options -> String -> m ()
gmUnsafePutStrLn opts = (fst $ outputFns' opts GmOutputStdio) . toGmLines
gmUnsafeErrStrLn opts = (snd $ outputFns' opts GmOutputStdio) . toGmLines
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gmReadProcess :: GmEnv m => m (FilePath -> [String] -> String -> IO String)
gmReadProcess = do
GhcModEnv {..} <- gmeAsk
case gmOutput of
GmOutputChan _ ->
readProcessStderrChan
GmOutputStdio ->
return $ readProcess
stdoutGateway :: Chan (GmStream, GmLines String) -> IO ()
stdoutGateway chan = go ("", "")
where
go buf@(obuf, ebuf) = do
(stream, GmLines ty l) <- readChan chan
case ty of
GmTerminated ->
case stream of
GmOut -> putStr (obuf++l) >> go ("", ebuf)
GmErr -> putStr (ebuf++l) >> go (obuf, "")
GmPartial -> case reverse $ lines l of
[] -> go buf
[x] -> go (appendBuf stream buf x)
x:xs -> do
putStr $ unlines $ reverse xs
go (appendBuf stream buf x)
appendBuf GmOut (obuf, ebuf) s = (obuf++s, ebuf)
appendBuf GmErr (obuf, ebuf) s = (obuf, ebuf++s)
readProcessStderrChan ::
GmEnv m => m (FilePath -> [String] -> String -> IO String)
readProcessStderrChan = do
(_, e) <- outputFns
return $ go e
where
go :: (GmLines String -> IO ()) -> FilePath -> [String] -> String -> IO String
go putErr exe args input = do
let cp = (proc exe args) {
std_out = CreatePipe
, std_err = CreatePipe
, std_in = CreatePipe
}
(Just i, Just o, Just e, h) <- createProcess cp
_ <- forkIO $ reader e
output <- hGetContents o
withForkWait (evaluate $ rnf output) $ \waitOut -> do
-- now write any input
unless (null input) $
ignoreSEx $ hPutStr i input
-- hClose performs implicit hFlush, and thus may trigger a SIGPIPE
ignoreSEx $ hClose i
-- wait on the output
waitOut
hClose o
res <- waitForProcess h
case res of
ExitFailure rv ->
processFailedException "readProcessStderrChan" exe args rv
ExitSuccess ->
return output
where
ignoreSEx = handle (\(SomeException _) -> return ())
reader h = ignoreSEx $ do
putErr . toGmLines . (++"\n") =<< hGetLine h
reader h
withForkWait :: IO () -> (IO () -> IO a) -> IO a
withForkWait async body = do
waitVar <- newEmptyMVar :: IO (MVar (Either SomeException ()))
mask $ \restore -> do
tid <- forkIO $ try (restore async) >>= putMVar waitVar
let wait = takeMVar waitVar >>= either throwIO return
restore (body wait) `onException` killThread tid
processFailedException :: String -> String -> [String] -> Int -> IO a
processFailedException fn exe args rv =
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error $ concat [ fn, ": ", exe, " "
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, intercalate " " (map show args)
, " (exit " ++ show rv ++ ")"]