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).

3 files changed, 5 insertions, 92 deletions

diff --git a/utils/iserv/iserv.cabal.in b/utils/iserv/iserv.cabal.in
index 46a0357a63..2460963d8c 100644
--- a/utils/iserv/iserv.cabal.in
+++ b/utils/iserv/iserv.cabal.in
@@ -18,9 +18,6 @@ Description:
   compiling Template Haskell, by spawning a separate delegate (so
   called runner on the javascript vm) and evaluating the splices
   there.
-  .
-  To use iserv with cross compilers, please see @libraries/libiserv@
-  and @utils/iserv-proxy@.
 
 Category: Development
 build-type: Simple
@@ -39,8 +36,7 @@ Executable iserv
                    bytestring >= 0.10 && < 0.12,
                    containers >= 0.5 && < 0.7,
                    deepseq    >= 1.4 && < 1.5,
-                   ghci       == @ProjectVersionMunged@,
-                   libiserv   == @ProjectVersionMunged@
+                   ghci       == @ProjectVersionMunged@
 
     if os(windows)
         Cpp-Options: -DWINDOWS
diff --git a/utils/iserv/src/Main.hs b/utils/iserv/src/Main.hs
index 4c622f85a9..c455ea1f01 100644
--- a/utils/iserv/src/Main.hs
+++ b/utils/iserv/src/Main.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE CPP, GADTs #-}
-
 -- |
 -- The Remote GHCi server.
 --
@@ -8,88 +6,7 @@
 --
 module Main (main) where
 
-import IServ (serv)
-
-import GHCi.Message
-import GHCi.Signals
-import GHCi.Utils
-
-import Control.Exception
-import Control.Concurrent (threadDelay)
-import Control.Monad
-import Data.IORef
-import System.Environment
-import System.Exit
-import Text.Printf
-#if defined(WINDOWS)
-import Foreign.Ptr (wordPtrToPtr)
-# if defined(__IO_MANAGER_WINIO__)
-import GHC.IO.SubSystem ((<!>))
-import GHC.Event.Windows (associateHandle')
-# endif
-#endif
-
-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
+import GHCi.Server (defaultServer)
 
 main :: IO ()
-main = do
-  args <- getArgs
-  (outh, inh, rest) <-
-      case args of
-        arg0:arg1:rest -> do
-#if defined(WINDOWS)
-            let wfd1 = wordPtrToPtr (read arg0)
-                rfd2 = wordPtrToPtr (read arg1)
-# if defined(__IO_MANAGER_WINIO__)
-            -- register the handles we received with
-            -- our I/O manager otherwise we can't use
-            -- them correctly.
-            return () <!> (do
-              associateHandle' wfd1
-              associateHandle' rfd2)
-# endif
-#else
-            let wfd1 = read arg0
-                rfd2 = read arg1
-#endif
-            inh  <- getGhcHandle rfd2
-            outh <- getGhcHandle wfd1
-            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.
+main = defaultServer
diff --git a/utils/remote-iserv/remote-iserv.cabal.in b/utils/remote-iserv/remote-iserv.cabal.in
index 7ecf099eac..24c5c99c74 100644
--- a/utils/remote-iserv/remote-iserv.cabal.in
+++ b/utils/remote-iserv/remote-iserv.cabal.in
@@ -13,7 +13,7 @@ Synopsis: iserv allows GHC to delegate Template Haskell computations
 Description:
   This is a very simple remote runner for iserv, to be used together
   with iserv-proxy.  The foundamental idea is that this this wrapper
-  starts running libiserv on a given port to which iserv-proxy will
+  starts running the GHCi server on a given port to which iserv-proxy will
   then connect.
 Category: Development
 build-type: Simple
@@ -24,4 +24,4 @@ Executable remote-iserv
    Main-Is: Cli.hs
    Hs-Source-Dirs: src
    Build-Depends: base       >= 4   && < 5,
-                  libiserv   == @ProjectVersionMunged@
+                  ghci       == @ProjectVersionMunged@