Merge branch 'master' into multi_proto_server

Merged the TCP port scanning from my master branch into the Main module.
Also merged the somewhat updated README.markdown file.

Conflicts:
	server/Main.hs
	server/scion-server.cabal

README.markdown

@@ -20,9 +20,9 @@ Installation
 
 Scion requires [GHC 6.10.1][ghc] or later.  All other dependencies
 should be on [Hackage][hackage] and can be installed using
-[cabal-install][ci]:
+[cabal-install][ci] in the lib directory:
 
-    $ cd dir/to/scion
+    $ cd dir/to/scion/lib
     $ cabal install
 
 Scion supports various configuration flags which are useful when
@@ -41,31 +41,28 @@ Since Scion is a library, you should consult the haddock documentation
 for how to use it.  However, you may look at the Emacs frontend for
 inspiration.
 
-The Emacs frontend is implemented as a Haskell server 
+The Emacs frontend is implemented as a Haskell server. The server is a
+separate package, scion-server, which depends on the main scion package.
 
 Emacs
 -----
 
-Install Scion with Emacs support, either via
+Install Scion with Emacs support:
 
-    $ cabal install scion -femacs
-
-or, if you have a locally copy of Scion
-
-    $ cd <scion>
-    $ cabal install -femacs
+    $ cd dir/to/scion/server
+    $ cabal install
 
-You'll end up with a binary called "emacs-server".
+You'll end up with a binary called "scion_server".
 
-    $ ./.cabal/bin/emacs_server
+    $ ~/.cabal/bin/scion_server
 
 Add the following to your emacs configuration (typically "~/.emacs"):
 
     (add-to-list 'load-path "<scion>/emacs")
     (require 'scion)
 
     ;; if ./cabal/bin is not in your $PATH
-    (setq scion-program "~/.cabal/bin/emacs_server")
+    (setq scion-program "~/.cabal/bin/scion_server")
 
     (defun my-haskell-hook ()
       ;; Whenever we open a file in Haskell mode, also activate Scion

lib/.gitignore

@@ -0,0 +1 @@
+dist

server/.gitignore

@@ -0,0 +1 @@
+dist

server/Main.hs

@@ -45,7 +45,7 @@ import Network.Socket.ByteString
 import Data.List (isPrefixOf, break)
 import Data.Foldable (foldrM)
 import qualified Control.Exception as E
-import Control.Monad ( when, forever )
+import Control.Monad ( when, forever, liftM )
 import System.Console.GetOpt
 
 
@@ -58,7 +58,7 @@ logError = log HL.ERROR
 -- if you're paranoid about your code Socketfile or StdInOut
 -- will be the most secure choice.. (Everyone can connect via TCP/IP at the
 -- moment)
-data ConnectionMode = TCPIP PortNumber
+data ConnectionMode = TCPIP Bool PortNumber -- the Bool indicates whether to scan
                   | StdInOut
 #ifndef mingw32_HOST_OS
                   | Socketfile FilePath
@@ -67,15 +67,19 @@ data ConnectionMode = TCPIP PortNumber
 
 data StartupConfig = StartupConfig {
      connectionMode :: ConnectionMode,
+     autoPort :: Bool,
      showHelp :: Bool
   } deriving Show
-defaultStartupConfig = StartupConfig ( TCPIP (fromInteger 4005)) False
+defaultStartupConfig = StartupConfig (TCPIP False (fromInteger 4005)) False False
 
 -- options :: [OptDescr (Options -> Options)]
 options =
      [ Option ['p']     ["port"]
-       (ReqArg (\o opts -> return $ opts { connectionMode = (TCPIP . fromInteger) (read o) }) "8010")
+       (ReqArg (\o opts -> return $ opts { connectionMode = (TCPIP False . fromInteger) (read o) }) "8010")
        "listen on this TCP port"
+     , Option ['a'] ["autoport"]
+       (NoArg (\opts -> return $ opts { autoPort = True }))
+       "scan until a free TCP port is found"
      , Option ['i'] ["stdinout"]
        (NoArg (\opts -> return $ opts { connectionMode = StdInOut}))
        "client must connect to stdin and stdout"
@@ -103,10 +107,24 @@ helpText = do
     let header = unlines [ "usage of scion server (executable :"  ++ pN  ++ ")" ]
     return $ usageInfo header options
 
+-- attempts to listen on each port in the list in turn, and returns the first successful
+listenOnOneOf :: [PortID] -> IO Socket
+listenOnOneOf (p:ps) = catch
+    (listenOn p)
+    (\(ex :: IOError) -> if null ps then E.throwIO ex else listenOnOneOf ps)
+
+-- this way, we can iterate until we find a free port number
+instance Bounded PortNumber where
+    minBound = 0
+    maxBound = 0xFFFF
+
 serve :: ConnectionMode -> IO ()
-serve (TCPIP nr) = do
-  sock <- liftIO $ listenOn (PortNumber nr)
-  putStrLn $ "=== Listening on port: " ++ show nr
+serve (TCPIP auto nr) = do
+  sock <- liftIO $ if auto
+                   then listenOnOneOf (map PortNumber [nr..maxBound])
+                   else listenOn (PortNumber nr)
+  realNr <- liftIO $ socketPort sock
+  putStrLn $ "=== Listening on port: " ++ show realNr
   forever $ E.handle (\(e::E.IOException) -> logInfo ("caught :" ++ (show e) ++ "\n\nwaiting for next client")) $ do
     (sock', _addr) <- liftIO $ accept sock
     sock_conn <- CIO.mkSocketConnection sock'
@@ -132,6 +150,11 @@ handleClient :: (CIO.ConnectionIO con) => con -> IO ()
 handleClient con = do
   runScion $ Gen.handle con 0
 
+fixConfig :: StartupConfig -> StartupConfig
+fixConfig conf = case connectionMode conf of
+  TCPIP _ nr -> conf { connectionMode = TCPIP (autoPort conf) nr }
+  otherwise -> conf
+
 main :: IO ()
 main = do
 
@@ -144,7 +167,7 @@ main = do
   when ((not . null) nonOpts) $
     logError $ "no additional arguments expected, got: " ++ (show nonOpts)
 
-  startupConfig <- foldrM ($) defaultStartupConfig opts
+  startupConfig <- return . fixConfig =<< foldrM ($) defaultStartupConfig opts
 
   -- help 
   when (showHelp startupConfig) $ helpText >>= putStrLn >> exitSuccess
@@ -155,6 +178,3 @@ main = do
   do
       log HL.DEBUG $ "opts: " ++ (show startupConfig)
       serve (connectionMode startupConfig)
-
-
-