hackport-0.8.3.0: src/Util.hs

{-|
    Author      :  Sergei Trofimovich <slyfox@inbox.ru>
    Stability   :  experimental
    Portability :  haskell98

    Ungrouped utilitary stuff lays here until someone finds better place for it :]
-}

module Util
    ( run_cmd -- :: String -> IO (Maybe String)
    , debug
    , notice
    , info
    , die
    ) where

import Control.Monad.IO.Class
import System.IO
import System.Process
import System.Exit (ExitCode(..))
import qualified Distribution.Simple.Utils as Cabal
import Hackport.Env

-- | 'run_cmd' executes command and returns it's standard output
--   as 'String'.
run_cmd :: MonadIO m => String -> m (Maybe String)
run_cmd cmd = liftIO $ do
    (hI, hO, hE, hProcess) <- runInteractiveCommand cmd
    hClose hI
    output <- hGetContents hO
    errors <- hGetContents hE -- TODO: propagate error to caller
    length output `seq` hClose hO
    length errors `seq` hClose hE

    exitCode <- waitForProcess hProcess
    return $ if (output == "" || exitCode /= ExitSuccess)
        then Nothing
        else Just output

debug :: (HasGlobalEnv m, MonadIO m) => String -> m ()
debug s = askGlobalEnv >>= \(GlobalEnv v _ _) -> liftIO $ Cabal.debug v s

notice :: (HasGlobalEnv m, MonadIO m) => String -> m ()
notice s = askGlobalEnv >>= \(GlobalEnv v _ _) -> liftIO $ Cabal.notice v s

info :: (HasGlobalEnv m, MonadIO m) => String -> m ()
info s = askGlobalEnv >>= \(GlobalEnv v _ _) -> liftIO $ Cabal.info v s

-- | Terminate with an error message
die :: (HasGlobalEnv m, MonadIO m) => String -> m a
die s = askGlobalEnv >>= \(GlobalEnv v _ _) -> liftIO $ Cabal.die' v s