--
-----------------------------------------------------------------------------
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
module GhciMonad where
#include "HsVersions.h"
import HscTypes
import SrcLoc
import Module
+import ObjLink
+import Data.Maybe
import Numeric
import Control.Exception as Exception
import Data.Array
prelude :: GHC.Module,
break_ctr :: !Int,
breaks :: ![(Int, BreakLocation)],
- tickarrays :: ModuleEnv TickArray
+ tickarrays :: ModuleEnv TickArray,
-- tickarrays caches the TickArray for loaded modules,
-- so that we don't rebuild it each time the user sets
-- a breakpoint.
+ cmdqueue :: [String]
}
type TickArray = Array Int [(BreakIndex,SrcSpan)]
{ breakModule :: !GHC.Module
, breakLoc :: !SrcSpan
, breakTick :: {-# UNPACK #-} !Int
+ , onBreakCmd :: String
}
- deriving Eq
+
+instance Eq BreakLocation where
+ loc1 == loc2 = breakModule loc1 == breakModule loc2 &&
+ breakTick loc1 == breakTick loc2
prettyLocations :: [(Int, BreakLocation)] -> SDoc
prettyLocations [] = text "No active breakpoints."
prettyLocations locs = vcat $ map (\(i, loc) -> brackets (int i) <+> ppr loc) $ reverse $ locs
instance Outputable BreakLocation where
- ppr loc = (ppr $ breakModule loc) <+> ppr (breakLoc loc)
+ ppr loc = (ppr $ breakModule loc) <+> ppr (breakLoc loc) <+>
+ if null (onBreakCmd loc)
+ then empty
+ else doubleQuotes (text (onBreakCmd loc))
recordBreak :: BreakLocation -> GHCi (Bool{- was already present -}, Int)
recordBreak brkLoc = do
(GHCi m) >>= k = GHCi $ \s -> m s >>= \a -> unGHCi (k a) s
return a = GHCi $ \s -> return a
+instance Functor GHCi where
+ fmap f m = m >>= return . f
+
ghciHandleDyn :: Typeable t => (t -> GHCi a) -> GHCi a -> GHCi a
ghciHandleDyn h (GHCi m) = GHCi $ \s ->
Exception.catchDyn (m s) (\e -> unGHCi (h e) s)
-- To flush buffers for the *interpreted* computation we need
-- to refer to *its* stdout/stderr handles
-GLOBAL_VAR(flush_interp, error "no flush_interp", IO ())
-GLOBAL_VAR(turn_off_buffering, error "no flush_stdout", IO ())
-
-command_sequence :: [String] -> String
-command_sequence = unwords . intersperse "Prelude.>>"
+GLOBAL_VAR(stdin_ptr, error "no stdin_ptr", Ptr ())
+GLOBAL_VAR(stdout_ptr, error "no stdout_ptr", Ptr ())
+GLOBAL_VAR(stderr_ptr, error "no stderr_ptr", Ptr ())
-no_buffer :: String -> String
-no_buffer h = unwords ["System.IO.hSetBuffering",
- "System.IO." ++ h,
- "System.IO.NoBuffering"]
-
-no_buf_cmd :: String
-no_buf_cmd = command_sequence $ map no_buffer ["stdout", "stderr", "stdin"]
-
-flush_buffer :: String -> String
-flush_buffer h = unwords ["System.IO.hFlush", "System.IO." ++ h]
-
-flush_cmd :: String
-flush_cmd = command_sequence [flush_buffer "stdout", flush_buffer "stderr"]
+-- After various attempts, I believe this is the least bad way to do
+-- what we want. We know look up the address of the static stdin,
+-- stdout, and stderr closures in the loaded base package, and each
+-- time we need to refer to them we cast the pointer to a Handle.
+-- This avoids any problems with the CAF having been reverted, because
+-- we'll always get the current value.
+--
+-- The previous attempt that didn't work was to compile an expression
+-- like "hSetBuffering stdout NoBuffering" into an expression of type
+-- IO () and run this expression each time we needed it, but the
+-- problem is that evaluating the expression might cache the contents
+-- of the Handle rather than referring to it from its static address
+-- each time. There's no safe workaround for this.
initInterpBuffering :: GHC.Session -> IO ()
initInterpBuffering session
- = do -- we don't want to be fooled by any modules lying around in the current
- -- directory when we compile these code fragments, so set the import
- -- path to be empty while we compile them.
- dflags <- GHC.getSessionDynFlags session
- GHC.setSessionDynFlags session dflags{importPaths=[]}
-
- maybe_hval <- GHC.compileExpr session no_buf_cmd
-
- case maybe_hval of
- Just hval -> writeIORef turn_off_buffering (unsafeCoerce# hval :: IO ())
- other -> panic "interactiveUI:setBuffering"
-
- maybe_hval <- GHC.compileExpr session flush_cmd
- case maybe_hval of
- Just hval -> writeIORef flush_interp (unsafeCoerce# hval :: IO ())
- _ -> panic "interactiveUI:flush"
-
- GHC.setSessionDynFlags session dflags
- GHC.workingDirectoryChanged session
+ = do -- make sure these are linked
+ mb_hval1 <- GHC.compileExpr session "System.IO.stdout"
+ mb_hval2 <- GHC.compileExpr session "System.IO.stderr"
+ mb_hval3 <- GHC.compileExpr session "System.IO.stdin"
+ when (any isNothing [mb_hval1,mb_hval2,mb_hval3]) $
+ panic "interactiveUI:setBuffering"
+
+ -- ToDo: we should really look up these names properly, but
+ -- it's a fiddle and not all the bits are exposed via the GHC
+ -- interface.
+ mb_stdin_ptr <- ObjLink.lookupSymbol "base_GHCziHandle_stdin_closure"
+ mb_stdout_ptr <- ObjLink.lookupSymbol "base_GHCziHandle_stdout_closure"
+ mb_stderr_ptr <- ObjLink.lookupSymbol "base_GHCziHandle_stderr_closure"
+
+ let f ref (Just ptr) = writeIORef ref ptr
+ f ref Nothing = panic "interactiveUI:setBuffering2"
+ zipWithM f [stdin_ptr,stdout_ptr,stderr_ptr]
+ [mb_stdin_ptr,mb_stdout_ptr,mb_stderr_ptr]
return ()
-
flushInterpBuffers :: GHCi ()
flushInterpBuffers
- = io $ do Monad.join (readIORef flush_interp)
- return ()
+ = io $ do getHandle stdout_ptr >>= hFlush
+ getHandle stderr_ptr >>= hFlush
turnOffBuffering :: IO ()
turnOffBuffering
- = do Monad.join (readIORef turn_off_buffering)
- return ()
+ = do hdls <- mapM getHandle [stdin_ptr,stdout_ptr,stderr_ptr]
+ mapM_ (\h -> hSetBuffering h NoBuffering) hdls
+
+getHandle :: IORef (Ptr ()) -> IO Handle
+getHandle ref = do
+ (Ptr addr) <- readIORef ref
+ case addrToHValue# addr of (# hval #) -> return (unsafeCoerce# hval)
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