From 6591e2b974ac22cbc2a06141edef76a775726e11 Mon Sep 17 00:00:00 2001
From: Joey Hess <joeyh@joeyh.name>
Date: Wed, 26 Apr 2017 14:23:37 -0400
Subject: have server relay Devloper messages to other Developers

---
 Server.hs | 45 ++++++++++++++++++++++++++++++---------------
 1 file changed, 30 insertions(+), 15 deletions(-)

(limited to 'Server.hs')

diff --git a/Server.hs b/Server.hs
index 5de184d..0906937 100644
--- a/Server.hs
+++ b/Server.hs
@@ -14,6 +14,7 @@ import Network.Wai.Handler.WebSockets
 import Network.WebSockets hiding (Message)
 import qualified Network.WebSockets as WS
 import Network.HTTP.Types
+import Control.Concurrent
 import Control.Concurrent.STM
 import Control.Concurrent.STM.TMChan
 import Control.Concurrent.Async
@@ -24,6 +25,7 @@ import qualified Data.Text as T
 import Data.Time.Clock.POSIX
 import System.IO
 import System.Directory
+import System.Mem.Weak
 
 type ServerState = M.Map SessionID Session
 
@@ -33,17 +35,21 @@ newServerState = newTVarIO M.empty
 -- | A session consists of a broadcast TMChan, which both users and
 -- developers write messages to. Writes are stored in the log file,
 -- and a log lock allows atomic access to the log file for replays.
-data Session = Session (TMChan Log) (TVar Handle) (TMVar LogLock)
+data Session = Session (TMChan (Broadcast Log)) (TVar Handle) (TMVar LogLock)
 
 data LogLock = LogLock
 
+-- | A broadcast message, with the ThreadId of the sending thread
+-- (which probably wants to ignore the message it sent).
+data Broadcast a = Broadcast a (Weak ThreadId)
+
 newSession :: TVar Handle -> IO Session
 newSession loghv = Session
 	<$> newBroadcastTMChanIO
 	<*> pure loghv
 	<*> newTMVarIO LogLock
 
-listenSession :: Session -> STM (TMChan Log)
+listenSession :: Session -> STM (TMChan (Broadcast Log))
 listenSession (Session bchan _ _) = dupTMChan bchan
 
 -- | While writing a log to the session the LogLock is drained until
@@ -55,9 +61,10 @@ writeSession (Session bchan loghv loglock) l = do
 		<$> takeTMVar loglock
 		<*> readTVar loghv
 	writeLogHandle l logh
+	tid <- mkWeakThreadId =<< myThreadId
 	atomically $ do
 		putTMVar loglock ll
-		writeTMChan bchan l
+		writeTMChan bchan (Broadcast l tid)
 
 -- | Run an action with the log file quiescent (and its write handle closed),
 -- and nothing being added to the session's broadcast TMChan.
@@ -145,7 +152,7 @@ user o ssv conn = withSessionID (serverDirectory o) $ \(loghv, sid) -> do
 	relaytouser userchan = do
 		v <- atomically $ readTMChan userchan
 		case v of
-			Just l -> case loggedMessage l of
+			Just (Broadcast l _from) -> case loggedMessage l of
 				Developer m -> do
 					sendBinaryData conn (LogMessage (Developer m))
 					relaytouser userchan
@@ -169,8 +176,9 @@ developer o ssv sid conn = bracket setup cleanup go
 	go (Just session) = do
 		sendBinaryData conn (Ready ServerSends sid)
 		devchan <- replayBacklogAndListen o sid session conn
+		mytid <- myThreadId
 		_ <- relayfromdeveloper session
-			`concurrently` relaytodeveloper devchan
+			`concurrently` relaytodeveloper mytid devchan
 		return ()
 	
 	-- Relay all Developer amessages from the developer's websocket
@@ -183,17 +191,24 @@ developer o ssv sid conn = bracket setup cleanup go
 	
 	-- Relay user messages from the developer's clone of the
 	-- broadcast channel to the developer's websocket.
-	relaytodeveloper devchan = do
+	relaytodeveloper mytid devchan = do
 		v <- atomically $ readTMChan devchan
 		case v of
-			Just l -> case loggedMessage l of
-				User m -> do
-					sendBinaryData conn (LogMessage (User m))
-					relaytodeveloper devchan
-				-- TODO: Relay messages from other
-				-- developers, without looping back
-				-- the developer's own messages.
-				Developer _ -> relaytodeveloper devchan
+			Just (Broadcast l from) -> do
+				let sendit = sendBinaryData conn
+					(LogMessage $ loggedMessage l)
+				case loggedMessage l of
+					User _ -> sendit
+					-- Relay messages from other
+					-- developers, without looping
+					-- back the developer's own messages.
+					Developer _ -> do
+						mtid <- deRefWeak from
+						case mtid of
+							Just tid | tid == mytid ->
+								return ()
+							_ -> sendit
+				relaytodeveloper mytid devchan
 			Nothing -> do
 				sendBinaryData conn Done
 				return ()
@@ -207,7 +222,7 @@ developer o ssv sid conn = bracket setup cleanup go
 --
 -- Note that the session may appear to freeze for other users while
 -- this is running.
-replayBacklogAndListen :: ServerOpts -> SessionID -> Session -> WS.Connection -> IO (TMChan Log)
+replayBacklogAndListen :: ServerOpts -> SessionID -> Session -> WS.Connection -> IO (TMChan (Broadcast Log))
 replayBacklogAndListen o sid session conn = 
 	preventWriteWhile session o sid $ do
 		replayBacklog o sid conn
-- 
cgit v1.2.3