Merge libiserv with ghci

`libiserv` serves no purpose. As it depends on `ghci` and doesn't have
more dependencies than the `ghci` package, its code could live in the
`ghci` package too.

This commit also moves most of the code from the `iserv` program into
the `ghci` package as well so that it can be reused. This is especially
useful for the implementation of TH for the JS backend (#22261, !9779).

8 files changed, 93 insertions, 143 deletions

diff --git a/libraries/libiserv/src/IServ.hs b/libraries/ghci/GHCi/Server.hs
index 6361a8c04c..f46060a01c 100644
--- a/libraries/libiserv/src/IServ.hs
+++ b/libraries/ghci/GHCi/Server.hs
@@ -1,17 +1,27 @@
-{-# LANGUAGE RankNTypes, RecordWildCards, GADTs, ScopedTypeVariables #-}
-module IServ (serv) where
+{-# LANGUAGE CPP, RankNTypes, RecordWildCards, GADTs, ScopedTypeVariables #-}
+module GHCi.Server
+  ( serv
+  , defaultServer
+  )
+where
 
+import Prelude
 import GHCi.Run
 import GHCi.TH
 import GHCi.Message
+import GHCi.Signals
+import GHCi.Utils
 
 import Control.DeepSeq
 import Control.Exception
 import Control.Monad
+import Control.Concurrent (threadDelay)
 import Data.Binary
+import Data.IORef
 
 import Text.Printf
-import System.Environment (getProgName)
+import System.Environment (getProgName, getArgs)
+import System.Exit
 
 type MessageHook = Msg -> IO Msg
 
@@ -84,3 +94,55 @@ serv verbose hook pipe restore = loop
       Left UserInterrupt -> return () >> discardCtrlC
       Left e -> throwIO e
       _ -> return ()
+
+-- | Default server
+defaultServer :: IO ()
+defaultServer = do
+  args <- getArgs
+  (outh, inh, rest) <-
+      case args of
+        arg0:arg1:rest -> do
+            inh  <- readGhcHandle arg1
+            outh <- readGhcHandle arg0
+            return (outh, inh, rest)
+        _ -> dieWithUsage
+
+  (verbose, rest') <- case rest of
+    "-v":rest' -> return (True, rest')
+    _ -> return (False, rest)
+
+  (wait, rest'') <- case rest' of
+    "-wait":rest'' -> return (True, rest'')
+    _ -> return (False, rest')
+
+  unless (null rest'') $
+    dieWithUsage
+
+  when verbose $
+    printf "GHC iserv starting (in: %s; out: %s)\n" (show inh) (show outh)
+  installSignalHandlers
+  lo_ref <- newIORef Nothing
+  let pipe = Pipe{pipeRead = inh, pipeWrite = outh, pipeLeftovers = lo_ref}
+
+  when wait $ do
+    when verbose $
+      putStrLn "Waiting 3s"
+    threadDelay 3000000
+
+  uninterruptibleMask $ serv verbose hook pipe
+
+  where hook = return -- empty hook
+    -- we cannot allow any async exceptions while communicating, because
+    -- we will lose sync in the protocol, hence uninterruptibleMask.
+
+dieWithUsage :: IO a
+dieWithUsage = do
+    prog <- getProgName
+    die $ prog ++ ": " ++ msg
+  where
+#if defined(WINDOWS)
+    msg = "usage: iserv <write-handle> <read-handle> [-v]"
+#else
+    msg = "usage: iserv <write-fd> <read-fd> [-v]"
+#endif
+
diff --git a/libraries/libiserv/src/GHCi/Utils.hsc b/libraries/ghci/GHCi/Utils.hsc
index 6b6613ad1b..43ab4a8550 100644
--- a/libraries/libiserv/src/GHCi/Utils.hsc
+++ b/libraries/ghci/GHCi/Utils.hsc
@@ -1,12 +1,15 @@
 {-# LANGUAGE CPP #-}
 module GHCi.Utils
-    ( getGhcHandle
-    ) where
+  ( getGhcHandle
+  , readGhcHandle
+  )
+where
 
+import Prelude
 import Foreign.C
 import GHC.IO.Handle (Handle())
 #if defined(mingw32_HOST_OS)
-import Foreign.Ptr (ptrToIntPtr)
+import Foreign.Ptr (ptrToIntPtr,wordPtrToPtr)
 import GHC.IO (onException)
 import GHC.IO.Handle.FD (fdToHandle)
 import GHC.Windows (HANDLE)
@@ -16,12 +19,13 @@ import GHC.IO.Device as IODevice
 import GHC.IO.Encoding (getLocaleEncoding)
 import GHC.IO.IOMode
 import GHC.IO.Windows.Handle (fromHANDLE, Io(), NativeHandle())
+
+#include <fcntl.h>     /* for _O_BINARY */
+
 #else
 import System.Posix
 #endif
 
-#include <fcntl.h>     /* for _O_BINARY */
-
 -- | Gets a GHC Handle File description from the given OS Handle or POSIX fd.
 
 #if defined(mingw32_HOST_OS)
@@ -48,3 +52,20 @@ foreign import ccall "io.h _open_osfhandle" _open_osfhandle ::
 getGhcHandle :: CInt -> IO Handle
 getGhcHandle fd     = fdToHandle $ Fd fd
 #endif
+
+-- | Read a handle passed on the command-line and prepare it to be used with the IO manager
+readGhcHandle :: String -> IO Handle
+readGhcHandle s = do
+#if defined(mingw32_HOST_OS)
+  let fd = wordPtrToPtr (Prelude.read s)
+# if defined(__IO_MANAGER_WINIO__)
+  -- register the handles we received with
+  -- our I/O manager otherwise we can't use
+  -- them correctly.
+  return () <!> associateHandle' fd
+# endif
+#else
+  let fd = Prelude.read s
+#endif
+  getGhcHandle fd
+
diff --git a/libraries/ghci/ghci.cabal.in b/libraries/ghci/ghci.cabal.in
index 78466a814a..700b7d62ea 100644
--- a/libraries/ghci/ghci.cabal.in
+++ b/libraries/ghci/ghci.cabal.in
@@ -57,6 +57,7 @@ library
             GHCi.Signals
             GHCi.StaticPtrTable
             GHCi.TH
+            GHCi.Server
 
     exposed-modules:
         GHCi.BreakArray
@@ -66,6 +67,7 @@ library
         GHCi.RemoteTypes
         GHCi.FFI
         GHCi.TH.Binary
+        GHCi.Utils
 
     Build-Depends:
         rts,
diff --git a/libraries/libiserv/.gitignore b/libraries/libiserv/.gitignore
deleted file mode 100644
index 89cf73d0b3..0000000000
--- a/libraries/libiserv/.gitignore
+++ /dev/null
@@ -1,4 +0,0 @@
-GNUmakefile
-/dist-install/
-/dist/
-ghc.mk
diff --git a/libraries/libiserv/LICENSE b/libraries/libiserv/LICENSE
deleted file mode 100644
index fe00a83ea9..0000000000
--- a/libraries/libiserv/LICENSE
+++ /dev/null
@@ -1,62 +0,0 @@
-This library (libraries/ghc-prim) is derived from code from several
-sources: 
-
-  * Code from the GHC project which is largely (c) The University of
-    Glasgow, and distributable under a BSD-style license (see below),
-
-  * Code from the Haskell 98 Report which is (c) Simon Peyton Jones
-    and freely redistributable (but see the full license for
-    restrictions).
-
-The full text of these licenses is reproduced below.  All of the
-licenses are BSD-style or compatible.
-
------------------------------------------------------------------------------
-
-The Glasgow Haskell Compiler License
-
-Copyright 2004, The University Court of the University of Glasgow. 
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are met:
-
-- Redistributions of source code must retain the above copyright notice,
-this list of conditions and the following disclaimer.
- 
-- Redistributions in binary form must reproduce the above copyright notice,
-this list of conditions and the following disclaimer in the documentation
-and/or other materials provided with the distribution.
- 
-- Neither name of the University nor the names of its contributors may be
-used to endorse or promote products derived from this software without
-specific prior written permission. 
-
-THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY COURT OF THE UNIVERSITY OF
-GLASGOW AND THE CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
-INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
-FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
-UNIVERSITY COURT OF THE UNIVERSITY OF GLASGOW OR THE CONTRIBUTORS BE LIABLE
-FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
-OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
-DAMAGE.
-
------------------------------------------------------------------------------
-
-Code derived from the document "Report on the Programming Language
-Haskell 98", is distributed under the following license:
-
-  Copyright (c) 2002 Simon Peyton Jones
-
-  The authors intend this Report to belong to the entire Haskell
-  community, and so we grant permission to copy and distribute it for
-  any purpose, provided that it is reproduced in its entirety,
-  including this Notice.  Modified versions of this Report may also be
-  copied and distributed for any purpose, provided that the modified
-  version is clearly presented as such, and that it does not claim to
-  be a definition of the Haskell 98 Language.
-
diff --git a/libraries/libiserv/Makefile b/libraries/libiserv/Makefile
deleted file mode 100644
index 88656e7853..0000000000
--- a/libraries/libiserv/Makefile
+++ /dev/null
@@ -1,15 +0,0 @@
-# -----------------------------------------------------------------------------
-#
-# (c) 2009 The University of Glasgow
-#
-# This file is part of the GHC build system.
-#
-# To understand how the build system works and how to modify it, see
-#      https://gitlab.haskell.org/ghc/ghc/wikis/building/architecture
-#      https://gitlab.haskell.org/ghc/ghc/wikis/building/modifying
-#
-# -----------------------------------------------------------------------------
-
-dir = iserv
-TOP = ..
-include $(TOP)/mk/sub-makefile.mk
diff --git a/libraries/libiserv/cbits/iservmain.c b/libraries/libiserv/cbits/iservmain.c
deleted file mode 100644
index 5c88018d6b..0000000000
--- a/libraries/libiserv/cbits/iservmain.c
+++ /dev/null
@@ -1,17 +0,0 @@
-#include <rts/PosixSource.h>
-#include <Rts.h>
-
-#include <HsFFI.h>
-
-int main (int argc, char *argv[])
-{
-    RtsConfig conf = defaultRtsConfig;
-
-    // We never know what symbols GHC will look up in the future, so
-    // we must retain CAFs for running interpreted code.
-    conf.keep_cafs = 1;
-
-    conf.rts_opts_enabled = RtsOptsAll;
-    extern StgClosure ZCMain_main_closure;
-    hs_main(argc, argv, &ZCMain_main_closure, conf);
-}
diff --git a/libraries/libiserv/libiserv.cabal.in b/libraries/libiserv/libiserv.cabal.in
deleted file mode 100644
index 6f13a3da42..0000000000
--- a/libraries/libiserv/libiserv.cabal.in
+++ /dev/null
@@ -1,37 +0,0 @@
--- WARNING: libiserv.cabal is automatically generated from libiserv.cabal.in by
--- ../../configure.  Make sure you are editing libiserv.cabal.in, not
--- libiserv.cabal.
-
-Name: libiserv
-Version: @ProjectVersionMunged@
-Copyright: XXX
-License: BSD3
-License-File: LICENSE
-Author: XXX
-Maintainer: XXX
-Synopsis: Provides shared functionality between iserv and iserv-proxy.
-Description: Provides shared functionality between iserv and iserv-proxy.
-Category: Development
-build-type: Simple
-cabal-version: >=1.10
-
-Flag network
-    Description:   Build libiserv with over-the-network support
-    Default:       False
-
-Library
-    Default-Language: Haskell2010
-    Hs-Source-Dirs: src
-    Exposed-Modules: IServ
-                   , GHCi.Utils
-    Build-Depends: base       >= 4   && < 5,
-                   binary     >= 0.7 && < 0.11,
-                   bytestring >= 0.10 && < 0.12,
-                   containers >= 0.5 && < 0.7,
-                   deepseq    >= 1.4 && < 1.5,
-                   ghci       == @ProjectVersionMunged@
-
-    if os(windows)
-       Cpp-Options: -DWINDOWS
-   else
-       Build-Depends: unix   >= 2.7 && < 2.9