Start off on new version in didChanges from updateState

[lsp-test.git] / src / Language / Haskell / LSP / Test / Session.hs

diff --git a/src/Language/Haskell/LSP/Test/Session.hs b/src/Language/Haskell/LSP/Test/Session.hs
index 0553160aee215862ebb4fbad547f087a9fcbaca6..4b93e71bb5843c2f99fccf8f93bc5b2ade98dd4a 100644 (file)
--- a/src/Language/Haskell/LSP/Test/Session.hs
+++ b/src/Language/Haskell/LSP/Test/Session.hs
@@ -1,35 +1,55 @@
+{-# LANGUAGE CPP               #-}

 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE OverloadedStrings #-}

+{-# LANGUAGE GeneralizedNewtypeDeriving #-}

 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE FlexibleInstances #-}

+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE RankNTypes #-}

 
 module Language.Haskell.LSP.Test.Session
 
 module Language.Haskell.LSP.Test.Session

-  ( Session
+  ( Session(..)

   , SessionConfig(..)
   , SessionConfig(..)

+  , defaultConfig
+  , SessionMessage(..)

   , SessionContext(..)
   , SessionState(..)
   , SessionContext(..)
   , SessionState(..)

-  , MonadSessionConfig(..)

   , runSessionWithHandles
   , get
   , put
   , modify
   , modifyM
   , runSessionWithHandles
   , get
   , put
   , modify
   , modifyM

-  , ask)
+  , ask
+  , asks
+  , sendMessage
+  , updateState
+  , withTimeout
+  , getCurTimeoutId
+  , bumpTimeoutId
+  , logMsg
+  , LogMsgType(..)
+  )

 
 where
 
 
 where
 

+import Control.Applicative

 import Control.Concurrent hiding (yield)
 import Control.Exception
 import Control.Lens hiding (List)
 import Control.Monad
 import Control.Monad.IO.Class
 import Control.Monad.Except
 import Control.Concurrent hiding (yield)
 import Control.Exception
 import Control.Lens hiding (List)
 import Control.Monad
 import Control.Monad.IO.Class
 import Control.Monad.Except

+#if __GLASGOW_HASKELL__ == 806
+import Control.Monad.Fail
+#endif

 import Control.Monad.Trans.Reader (ReaderT, runReaderT)
 import qualified Control.Monad.Trans.Reader as Reader (ask)
 import Control.Monad.Trans.State (StateT, runStateT)
 import Control.Monad.Trans.Reader (ReaderT, runReaderT)
 import qualified Control.Monad.Trans.Reader as Reader (ask)
 import Control.Monad.Trans.State (StateT, runStateT)

-import qualified Control.Monad.Trans.State as State (get, put, modify)
+import qualified Control.Monad.Trans.State as State

 import qualified Data.ByteString.Lazy.Char8 as B
 import Data.Aeson
 import qualified Data.ByteString.Lazy.Char8 as B
 import Data.Aeson

-import Data.Conduit hiding (await)
-import Data.Conduit.Parser
+import Data.Aeson.Encode.Pretty
+import Data.Conduit as Conduit
+import Data.Conduit.Parser as Parser

 import Data.Default
 import Data.Foldable
 import Data.List
 import Data.Default
 import Data.Foldable
 import Data.List


@@ -38,200 +58,372 @@ import qualified Data.Text as T
 import qualified Data.Text.IO as T
 import qualified Data.HashMap.Strict as HashMap
 import Data.Maybe
 import qualified Data.Text.IO as T
 import qualified Data.HashMap.Strict as HashMap
 import Data.Maybe

+import Data.Function

 import Language.Haskell.LSP.Messages
 import Language.Haskell.LSP.Messages

-import Language.Haskell.LSP.TH.ClientCapabilities
-import Language.Haskell.LSP.Types hiding (error)
+import Language.Haskell.LSP.Types.Capabilities
+import Language.Haskell.LSP.Types
+import Language.Haskell.LSP.Types.Lens
+import qualified Language.Haskell.LSP.Types.Lens as LSP

 import Language.Haskell.LSP.VFS
 import Language.Haskell.LSP.Test.Compat
 import Language.Haskell.LSP.Test.Decoding
 import Language.Haskell.LSP.Test.Exceptions
 import Language.Haskell.LSP.VFS
 import Language.Haskell.LSP.Test.Compat
 import Language.Haskell.LSP.Test.Decoding
 import Language.Haskell.LSP.Test.Exceptions

+import System.Console.ANSI

 import System.Directory
 import System.IO
 import System.Directory
 import System.IO

+import System.Process (waitForProcess, ProcessHandle())
+import System.Timeout

 
 -- | A session representing one instance of launching and connecting to a server.
 --
 
 -- | A session representing one instance of launching and connecting to a server.
 --

--- You can send and receive messages to the server within 'Session' via 'getMessage',
--- 'sendRequest' and 'sendNotification'.
---
--- @
--- runSession \"path\/to\/root\/dir\" $ do
---   docItem <- getDocItem "Desktop/simple.hs" "haskell"
---   sendNotification TextDocumentDidOpen (DidOpenTextDocumentParams docItem)
---   diagnostics <- getMessage :: Session PublishDiagnosticsNotification
--- @
-type Session = ParserStateReader FromServerMessage SessionState SessionContext IO
+-- You can send and receive messages to the server within 'Session' via
+-- 'Language.Haskell.LSP.Test.message',
+-- 'Language.Haskell.LSP.Test.sendRequest' and
+-- 'Language.Haskell.LSP.Test.sendNotification'.
+
+newtype Session a = Session (ConduitParser FromServerMessage (StateT SessionState (ReaderT SessionContext IO)) a)
+  deriving (Functor, Applicative, Monad, MonadIO, Alternative)
+
+#if __GLASGOW_HASKELL__ >= 806
+instance MonadFail Session where
+  fail s = do
+    lastMsg <- fromJust . lastReceivedMessage <$> get
+    liftIO $ throw (UnexpectedMessage s lastMsg)
+#endif

 
 -- | Stuff you can configure for a 'Session'.
 data SessionConfig = SessionConfig
 
 -- | Stuff you can configure for a 'Session'.
 data SessionConfig = SessionConfig

-  {
-    capabilities :: ClientCapabilities -- ^ Specific capabilities the client should advertise. Default is yes to everything.
-  , timeout :: Int -- ^ Maximum time to wait for a request in seconds. Defaults to 60.
-  , logStdErr :: Bool -- ^ When True redirects the servers stderr output to haskell-lsp-test's stdout. Defaults to False
+  { messageTimeout :: Int  -- ^ Maximum time to wait for a message in seconds, defaults to 60.
+  , logStdErr      :: Bool
+  -- ^ Redirect the server's stderr to this stdout, defaults to False.
+  -- Can be overriden with @LSP_TEST_LOG_STDERR@.
+  , logMessages    :: Bool
+  -- ^ Trace the messages sent and received to stdout, defaults to False.
+  -- Can be overriden with the environment variable @LSP_TEST_LOG_MESSAGES@.
+  , logColor       :: Bool -- ^ Add ANSI color to the logged messages, defaults to True.
+  , lspConfig      :: Maybe Value -- ^ The initial LSP config as JSON value, defaults to Nothing.
+  , ignoreLogNotifications :: Bool
+  -- ^ Whether or not to ignore 'Language.Haskell.LSP.Types.ShowMessageNotification' and
+  -- 'Language.Haskell.LSP.Types.LogMessageNotification', defaults to False.
+  --
+  -- @since 0.9.0.0

   }
 
   }
 

-instance Default SessionConfig where
-  def = SessionConfig def 60 False
+-- | The configuration used in 'Language.Haskell.LSP.Test.runSession'.
+defaultConfig :: SessionConfig
+defaultConfig = SessionConfig 60 False False True Nothing False

 
 

-class Monad m => MonadSessionConfig m where
-  sessionConfig :: m SessionConfig
+instance Default SessionConfig where
+  def = defaultConfig

 
 

-instance Monad m => MonadSessionConfig (StateT SessionState (ReaderT SessionContext m)) where
-  sessionConfig = config <$> lift Reader.ask
+data SessionMessage = ServerMessage FromServerMessage
+                    | TimeoutMessage Int
+  deriving Show

 
 data SessionContext = SessionContext
   {
     serverIn :: Handle
   , rootDir :: FilePath
 
 data SessionContext = SessionContext
   {
     serverIn :: Handle
   , rootDir :: FilePath

-  , messageChan :: Chan FromServerMessage
+  , messageChan :: Chan SessionMessage -- ^ Where all messages come through
+  -- Keep curTimeoutId in SessionContext, as its tied to messageChan
+  , curTimeoutId :: MVar Int -- ^ The current timeout we are waiting on

   , requestMap :: MVar RequestMap
   , initRsp :: MVar InitializeResponse
   , config :: SessionConfig
   , requestMap :: MVar RequestMap
   , initRsp :: MVar InitializeResponse
   , config :: SessionConfig

+  , sessionCapabilities :: ClientCapabilities

   }
 
   }
 

+class Monad m => HasReader r m where
+  ask :: m r
+  asks :: (r -> b) -> m b
+  asks f = f <$> ask
+
+instance HasReader SessionContext Session where
+  ask  = Session (lift $ lift Reader.ask)
+
+instance Monad m => HasReader r (ConduitM a b (StateT s (ReaderT r m))) where
+  ask = lift $ lift Reader.ask
+
+getCurTimeoutId :: (HasReader SessionContext m, MonadIO m) => m Int
+getCurTimeoutId = asks curTimeoutId >>= liftIO . readMVar
+
+-- Pass this the timeoutid you *were* waiting on
+bumpTimeoutId :: (HasReader SessionContext m, MonadIO m) => Int -> m ()
+bumpTimeoutId prev = do
+  v <- asks curTimeoutId
+  -- when updating the curtimeoutid, account for the fact that something else
+  -- might have bumped the timeoutid in the meantime
+  liftIO $ modifyMVar_ v (\x -> pure (max x (prev + 1)))
+

 data SessionState = SessionState
   {
     curReqId :: LspId
   , vfs :: VFS
 data SessionState = SessionState
   {
     curReqId :: LspId
   , vfs :: VFS

+  , curDiagnostics :: Map.Map NormalizedUri [Diagnostic]
+  , overridingTimeout :: Bool
+  -- ^ The last received message from the server.
+  -- Used for providing exception information
+  , lastReceivedMessage :: Maybe FromServerMessage
+  , curDynCaps :: Map.Map T.Text Registration
+  -- ^ The capabilities that the server has dynamically registered with us so
+  -- far

   }
 
   }
 

-type ParserStateReader a s r m = ConduitParser a (StateT s (ReaderT r m))
+class Monad m => HasState s m where
+  get :: m s

 
 

-type SessionProcessor = ConduitM FromServerMessage FromServerMessage (StateT SessionState (ReaderT SessionContext IO))
+  put :: s -> m ()

 
 

-runSession :: Chan FromServerMessage -> SessionProcessor () -> SessionContext -> SessionState -> Session a -> IO (a, SessionState)
-runSession chan preprocessor context state session = runReaderT (runStateT conduit state) context
-  where conduit = runConduit $ chanSource chan .| preprocessor .| runConduitParser (catchError session handler)
-        handler e@(Unexpected "ConduitParser.empty") = do
+  modify :: (s -> s) -> m ()
+  modify f = get >>= put . f

 
 

-          -- Horrible way to get last item in conduit:
-          -- Add a fake message so we can tell when to stop
-          liftIO $ writeChan chan (RspShutdown (ResponseMessage "EMPTY" IdRspNull Nothing Nothing))
-          x <- peek
-          case x of
-            Just x -> do
-              lastMsg <- skipToEnd x
-              name <- getParserName
-              liftIO $ throw (UnexpectedMessageException (T.unpack name) lastMsg)
-            Nothing -> throw e
+  modifyM :: (HasState s m, Monad m) => (s -> m s) -> m ()
+  modifyM f = get >>= f >>= put

 
 

-        handler e = throw e
+instance HasState SessionState Session where
+  get = Session (lift State.get)
+  put = Session . lift . State.put
+
+instance Monad m => HasState s (StateT s m) where
+  get = State.get
+  put = State.put

 
 

-        skipToEnd x = do
-          y <- peek
-          case y of
-            Just (RspShutdown (ResponseMessage "EMPTY" IdRspNull Nothing Nothing)) -> return x
-            Just _ -> await >>= skipToEnd
-            Nothing -> return x
+instance (Monad m, (HasState s m)) => HasState s (ConduitM a b m)
+ where
+  get = lift get
+  put = lift . put
+
+instance (Monad m, (HasState s m)) => HasState s (ConduitParser a m)
+ where
+  get = lift get
+  put = lift . put

 
 

-get :: Monad m => ParserStateReader a s r m s
-get = lift State.get
+runSession :: SessionContext -> SessionState -> Session a -> IO (a, SessionState)
+runSession context state (Session session) = runReaderT (runStateT conduit state) context
+  where
+    conduit = runConduit $ chanSource .| watchdog .| updateStateC .| runConduitParser (catchError session handler)

 
 

-put :: Monad m => s -> ParserStateReader a s r m ()
-put = lift . State.put
+    handler (Unexpected "ConduitParser.empty") = do
+      lastMsg <- fromJust . lastReceivedMessage <$> get
+      name <- getParserName
+      liftIO $ throw (UnexpectedMessage (T.unpack name) lastMsg)

 
 

-modify :: Monad m => (s -> s) -> ParserStateReader a s r m ()
-modify = lift . State.modify
+    handler e = throw e

 
 

-modifyM :: Monad m => (s -> m s) -> ParserStateReader a s r m ()
-modifyM f = do
-  old <- lift State.get
-  new <- lift $ lift $ lift $ f old
-  lift $ State.put new
+    chanSource = do
+      msg <- liftIO $ readChan (messageChan context)
+      unless (ignoreLogNotifications (config context) && isLogNotification msg) $
+        yield msg
+      chanSource

 
 

-ask :: Monad m => ParserStateReader a s r m r
-ask = lift $ lift Reader.ask
+    isLogNotification (ServerMessage (NotShowMessage _)) = True
+    isLogNotification (ServerMessage (NotLogMessage _)) = True
+    isLogNotification _ = False
+
+    watchdog :: ConduitM SessionMessage FromServerMessage (StateT SessionState (ReaderT SessionContext IO)) ()
+    watchdog = Conduit.awaitForever $ \msg -> do
+      curId <- getCurTimeoutId
+      case msg of
+        ServerMessage sMsg -> yield sMsg
+        TimeoutMessage tId -> when (curId == tId) $ lastReceivedMessage <$> get >>= throw . Timeout

 
 -- | An internal version of 'runSession' that allows for a custom handler to listen to the server.
 -- It also does not automatically send initialize and exit messages.
 runSessionWithHandles :: Handle -- ^ Server in
                       -> Handle -- ^ Server out
 
 -- | An internal version of 'runSession' that allows for a custom handler to listen to the server.
 -- It also does not automatically send initialize and exit messages.
 runSessionWithHandles :: Handle -- ^ Server in
                       -> Handle -- ^ Server out

-                      -> (Handle -> Session ()) -- ^ Server listener
+                      -> ProcessHandle -- ^ Server process
+                      -> (Handle -> SessionContext -> IO ()) -- ^ Server listener

                       -> SessionConfig
                       -> SessionConfig

-                      -> FilePath
+                      -> ClientCapabilities
+                      -> FilePath -- ^ Root directory
+                      -> Session () -- ^ To exit the Server properly

                       -> Session a
                       -> IO a
                       -> Session a
                       -> IO a

-runSessionWithHandles serverIn serverOut serverHandler config rootDir session = do
+runSessionWithHandles serverIn serverOut serverProc serverHandler config caps rootDir exitServer session = do

   absRootDir <- canonicalizePath rootDir
 
   hSetBuffering serverIn  NoBuffering
   hSetBuffering serverOut NoBuffering
   absRootDir <- canonicalizePath rootDir
 
   hSetBuffering serverIn  NoBuffering
   hSetBuffering serverOut NoBuffering

+  -- This is required to make sure that we don’t get any
+  -- newline conversion or weird encoding issues.
+  hSetBinaryMode serverIn True
+  hSetBinaryMode serverOut True

 
   reqMap <- newMVar newRequestMap
   messageChan <- newChan
 
   reqMap <- newMVar newRequestMap
   messageChan <- newChan

-  meaninglessChan <- newChan
+  timeoutIdVar <- newMVar 0

   initRsp <- newEmptyMVar
 
   initRsp <- newEmptyMVar
 

-  let context = SessionContext serverIn absRootDir messageChan reqMap initRsp config
-      initState = SessionState (IdInt 0) mempty
+  mainThreadId <- myThreadId
+
+  let context = SessionContext serverIn absRootDir messageChan timeoutIdVar reqMap initRsp config caps
+      initState vfs = SessionState (IdInt 0) vfs mempty False Nothing mempty
+      runSession' ses = initVFS $ \vfs -> runSession context (initState vfs) ses
+
+      errorHandler = throwTo mainThreadId :: SessionException -> IO ()
+      serverListenerLauncher =
+        forkIO $ catch (serverHandler serverOut context) errorHandler
+      server = (Just serverIn, Just serverOut, Nothing, serverProc)
+      msgTimeoutMs = messageTimeout config * 10^6
+      serverAndListenerFinalizer tid = do
+        finally (timeout msgTimeoutMs (runSession' exitServer)) $ do
+          -- Make sure to kill the listener first, before closing
+          -- handles etc via cleanupProcess
+          killThread tid
+          -- Give the server some time to exit cleanly
+          timeout msgTimeoutMs (waitForProcess serverProc)
+          cleanupProcess server
+
+  (result, _) <- bracket serverListenerLauncher
+                         serverAndListenerFinalizer
+                         (const $ runSession' session)
+  return result

 
 

-  threadId <- forkIO $ void $ runSession meaninglessChan processor context initState (serverHandler serverOut)
-  (result, _) <- runSession messageChan processor context initState session
+updateStateC :: ConduitM FromServerMessage FromServerMessage (StateT SessionState (ReaderT SessionContext IO)) ()
+updateStateC = awaitForever $ \msg -> do
+  updateState msg
+  yield msg

 
 

-  killThread threadId
+updateState :: (MonadIO m, HasReader SessionContext m, HasState SessionState m)
+            => FromServerMessage -> m ()

 
 

-  return result
+-- Keep track of dynamic capability registration
+updateState (ReqRegisterCapability req) = do
+  let List newRegs = (\r -> (r ^. LSP.id, r)) <$> req ^. params . registrations
+  modify $ \s ->
+    s { curDynCaps = Map.union (Map.fromList newRegs) (curDynCaps s) }

 
 

-  where processor :: SessionProcessor ()
-        processor = awaitForever $ \msg -> do
-          processTextChanges msg
-          yield msg
+updateState (ReqUnregisterCapability req) = do
+  let List unRegs = (^. LSP.id) <$> req ^. params . unregistrations
+  modify $ \s ->
+    let newCurDynCaps = foldr' Map.delete (curDynCaps s) unRegs
+    in s { curDynCaps = newCurDynCaps }

 
 

+updateState (NotPublishDiagnostics n) = do
+  let List diags = n ^. params . diagnostics
+      doc = n ^. params . uri
+  modify $ \s ->
+    let newDiags = Map.insert (toNormalizedUri doc) diags (curDiagnostics s)
+      in s { curDiagnostics = newDiags }

 
 

-processTextChanges :: FromServerMessage -> SessionProcessor ()
-processTextChanges (ReqApplyWorkspaceEdit r) = do
+updateState (ReqApplyWorkspaceEdit r) = do

 
 

+  -- First, prefer the versioned documentChanges field

   allChangeParams <- case r ^. params . edit . documentChanges of
     Just (List cs) -> do
       mapM_ (checkIfNeedsOpened . (^. textDocument . uri)) cs
       return $ map getParams cs
   allChangeParams <- case r ^. params . edit . documentChanges of
     Just (List cs) -> do
       mapM_ (checkIfNeedsOpened . (^. textDocument . uri)) cs
       return $ map getParams cs

+    -- Then fall back to the changes field

     Nothing -> case r ^. params . edit . changes of
       Just cs -> do
         mapM_ checkIfNeedsOpened (HashMap.keys cs)
     Nothing -> case r ^. params . edit . changes of
       Just cs -> do
         mapM_ checkIfNeedsOpened (HashMap.keys cs)

-        return $ concatMap (uncurry getChangeParams) (HashMap.toList cs)
-      Nothing -> error "No changes!"
+        concat <$> mapM (uncurry getChangeParams) (HashMap.toList cs)
+      Nothing ->
+        error "WorkspaceEdit contains neither documentChanges nor changes!"

 
 

-  oldVFS <- vfs <$> lift State.get
-  newVFS <- liftIO $ changeFromServerVFS oldVFS r
-  lift $ State.modify (\s -> s { vfs = newVFS })
+  modifyM $ \s -> do
+    newVFS <- liftIO $ changeFromServerVFS (vfs s) r
+    return $ s { vfs = newVFS }

 
 

-  let groupedParams = groupBy (\a b -> (a ^. textDocument == b ^. textDocument)) allChangeParams
+  let groupedParams = groupBy (\a b -> a ^. textDocument == b ^. textDocument) allChangeParams

       mergedParams = map mergeParams groupedParams
 
       mergedParams = map mergeParams groupedParams
 

-  ctx <- lift $ lift Reader.ask
-

   -- TODO: Don't do this when replaying a session
   -- TODO: Don't do this when replaying a session

-  forM_ mergedParams $ \p -> do
-    let h = serverIn ctx
-        msg = NotificationMessage "2.0" TextDocumentDidChange p
-    liftIO $ B.hPut h $ addHeader (encode msg)
+  forM_ mergedParams (sendMessage . NotificationMessage "2.0" TextDocumentDidChange)
+
+  -- Update VFS to new document versions
+  let sortedVersions = map (sortBy (compare `on` (^. textDocument . version))) groupedParams
+      latestVersions = map ((^. textDocument) . last) sortedVersions
+      bumpedVersions = map (version . _Just +~ 1) latestVersions
+
+  forM_ bumpedVersions $ \(VersionedTextDocumentIdentifier uri v) ->
+    modify $ \s ->
+      let oldVFS = vfs s
+          update (VirtualFile oldV file_ver t) = VirtualFile (fromMaybe oldV v) (file_ver + 1) t
+          newVFS = updateVFS (Map.adjust update (toNormalizedUri uri)) oldVFS
+      in s { vfs = newVFS }

 
   where checkIfNeedsOpened uri = do
 
   where checkIfNeedsOpened uri = do

-          oldVFS <- vfs <$> lift State.get
-          ctx <- lift $ lift Reader.ask
+          oldVFS <- vfs <$> get
+          ctx <- ask

 
           -- if its not open, open it
 
           -- if its not open, open it

-          unless (uri `Map.member` oldVFS) $ do
+          unless (toNormalizedUri uri `Map.member` vfsMap oldVFS) $ do

             let fp = fromJust $ uriToFilePath uri
             contents <- liftIO $ T.readFile fp
             let item = TextDocumentItem (filePathToUri fp) "" 0 contents
                 msg = NotificationMessage "2.0" TextDocumentDidOpen (DidOpenTextDocumentParams item)
             liftIO $ B.hPut (serverIn ctx) $ addHeader (encode msg)
 
             let fp = fromJust $ uriToFilePath uri
             contents <- liftIO $ T.readFile fp
             let item = TextDocumentItem (filePathToUri fp) "" 0 contents
                 msg = NotificationMessage "2.0" TextDocumentDidOpen (DidOpenTextDocumentParams item)
             liftIO $ B.hPut (serverIn ctx) $ addHeader (encode msg)
 

-            oldVFS <- vfs <$> lift State.get
-            newVFS <- liftIO $ openVFS oldVFS msg
-            lift $ State.modify (\s -> s { vfs = newVFS })
+            modifyM $ \s -> do
+              let (newVFS,_) = openVFS (vfs s) msg
+              return $ s { vfs = newVFS }

 
         getParams (TextDocumentEdit docId (List edits)) =
           let changeEvents = map (\e -> TextDocumentContentChangeEvent (Just (e ^. range)) Nothing (e ^. newText)) edits
             in DidChangeTextDocumentParams docId (List changeEvents)
 
 
         getParams (TextDocumentEdit docId (List edits)) =
           let changeEvents = map (\e -> TextDocumentContentChangeEvent (Just (e ^. range)) Nothing (e ^. newText)) edits
             in DidChangeTextDocumentParams docId (List changeEvents)
 

-        textDocumentVersions uri = map (VersionedTextDocumentIdentifier uri) [0..]
+        -- For a uri returns an infinite list of versions [n,n+1,n+2,...]
+        -- where n is the current version
+        textDocumentVersions uri = do
+          m <- vfsMap . vfs <$> get
+          let curVer = fromMaybe 0 $
+                _lsp_version <$> m Map.!? (toNormalizedUri uri)
+          pure $ map (VersionedTextDocumentIdentifier uri . Just) [curVer + 1..]

 
 

-        textDocumentEdits uri edits = map (\(v, e) -> TextDocumentEdit v (List [e])) $ zip (textDocumentVersions uri) edits
+        textDocumentEdits uri edits = do
+          vers <- textDocumentVersions uri
+          pure $ map (\(v, e) -> TextDocumentEdit v (List [e])) $ zip vers edits

 
 

-        getChangeParams uri (List edits) = map getParams (textDocumentEdits uri (reverse edits))
+        getChangeParams uri (List edits) =
+          map <$> pure getParams <*> textDocumentEdits uri (reverse edits)

 
         mergeParams :: [DidChangeTextDocumentParams] -> DidChangeTextDocumentParams
         mergeParams params = let events = concat (toList (map (toList . (^. contentChanges)) params))
                               in DidChangeTextDocumentParams (head params ^. textDocument) (List events)
 
         mergeParams :: [DidChangeTextDocumentParams] -> DidChangeTextDocumentParams
         mergeParams params = let events = concat (toList (map (toList . (^. contentChanges)) params))
                               in DidChangeTextDocumentParams (head params ^. textDocument) (List events)

-processTextChanges _ = return ()
+updateState _ = return ()
+
+sendMessage :: (MonadIO m, HasReader SessionContext m, ToJSON a) => a -> m ()
+sendMessage msg = do
+  h <- serverIn <$> ask
+  logMsg LogClient msg
+  liftIO $ B.hPut h (addHeader $ encode msg)
+
+-- | Execute a block f that will throw a 'Language.Haskell.LSP.Test.Exception.Timeout' exception
+-- after duration seconds. This will override the global timeout
+-- for waiting for messages to arrive defined in 'SessionConfig'.
+withTimeout :: Int -> Session a -> Session a
+withTimeout duration f = do
+  chan <- asks messageChan
+  timeoutId <- getCurTimeoutId
+  modify $ \s -> s { overridingTimeout = True }
+  liftIO $ forkIO $ do
+    threadDelay (duration * 1000000)
+    writeChan chan (TimeoutMessage timeoutId)
+  res <- f
+  bumpTimeoutId timeoutId
+  modify $ \s -> s { overridingTimeout = False }
+  return res
+
+data LogMsgType = LogServer | LogClient
+  deriving Eq
+
+-- | Logs the message if the config specified it
+logMsg :: (ToJSON a, MonadIO m, HasReader SessionContext m)
+       => LogMsgType -> a -> m ()
+logMsg t msg = do
+  shouldLog <- asks $ logMessages . config
+  shouldColor <- asks $ logColor . config
+  liftIO $ when shouldLog $ do
+    when shouldColor $ setSGR [SetColor Foreground Dull color]
+    putStrLn $ arrow ++ showPretty msg
+    when shouldColor $ setSGR [Reset]
+
+  where arrow
+          | t == LogServer  = "<-- "
+          | otherwise       = "--> "
+        color
+          | t == LogServer  = Magenta
+          | otherwise       = Cyan
+
+        showPretty = B.unpack . encodePretty