From 94fc4e6fd26ed2ca441ed805a5210f20ac64ef19 Mon Sep 17 00:00:00 2001
From: Dmitriy Ryajov <dryajov@gmail.com>
Date: Wed, 12 Feb 2020 09:37:22 -0500
Subject: [PATCH] don't use sleeps for synchronization

---
 libp2p/muxers/mplex/coder.nim | 18 ++++++++----------
 libp2p/muxers/mplex/mplex.nim | 22 ++++++++++------------
 2 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/libp2p/muxers/mplex/coder.nim b/libp2p/muxers/mplex/coder.nim
index 7e6c9a4bc..0451805d4 100644
--- a/libp2p/muxers/mplex/coder.nim
+++ b/libp2p/muxers/mplex/coder.nim
@@ -43,21 +43,19 @@ proc readMplexVarint(conn: Connection): Future[Option[uint]] {.async, gcsafe.} =
   except LPStreamIncompleteError as exc:
     trace "unable to read varint", exc = exc.msg
 
-proc readMsg*(conn: Connection): Future[Option[Msg]] {.async, gcsafe.} =
+proc readMsg*(conn: Connection): Future[Msg] {.async, gcsafe.} =
   let headerVarint = await conn.readMplexVarint()
-  if headerVarint.isNone:
-    return
-
-  trace "read header varint", varint = $headerVarint
+  trace "read header varint", varint = headerVarint
 
   let dataLenVarint = await conn.readMplexVarint()
+  trace "read data len varing", varint = dataLenVarint
   var data: seq[byte]
-  if dataLenVarint.isSome and dataLenVarint.get() > 0.uint:
-    data = await conn.read(dataLenVarint.get().int)
-    trace "read size varint", varint = $dataLenVarint
+  if dataLenVarint.int > 0:
+    data = await conn.read(dataLenVarint.int)
+    trace "read data", data = data
 
-  let header = headerVarint.get()
-  result = some((header shr 3, MessageType(header and 0x7), data))
+  let header = headerVarint
+  result = (header shr 3, MessageType(header and 0x7), data)
 
 proc writeMsg*(conn: Connection,
                id: uint,
diff --git a/libp2p/muxers/mplex/mplex.nim b/libp2p/muxers/mplex/mplex.nim
index 4a8769daa..41c49eb5d 100644
--- a/libp2p/muxers/mplex/mplex.nim
+++ b/libp2p/muxers/mplex/mplex.nim
@@ -23,6 +23,8 @@ import ../muxer,
 logScope:
   topic = "Mplex"
 
+const DefaultRWTimeout = InfiniteDuration
+
 type
   Mplex* = ref object of Muxer
     remote*: Table[uint, LPChannel]
@@ -64,14 +66,10 @@ method handle*(m: Mplex) {.async, gcsafe.} =
   try:
     while not m.connection.closed:
       trace "waiting for data"
-      let msg = await m.connection.readMsg()
-      if msg.isNone:
-        trace "connection EOF"
-        # TODO: allow poll with timeout to avoid using `sleepAsync`
-        await sleepAsync(1.millis)
-        continue
-
-      let (id, msgType, data) = msg.get()
+      let (id, msgType, data) = await m.connection.readMsg()
+      trace "read message from connection", id = id,
+                                            msgType = msgType,
+                                            data = data
       let initiator = bool(ord(msgType) and 1)
       var channel: LPChannel
       if MessageType(msgType) != MessageType.New:
@@ -80,7 +78,6 @@ method handle*(m: Mplex) {.async, gcsafe.} =
           trace "Channel not found, skipping", id = id,
                                                initiator = initiator,
                                                msg = msgType
-          await sleepAsync(1.millis)
           continue
         channel = channels[id]
 
@@ -99,7 +96,6 @@ method handle*(m: Mplex) {.async, gcsafe.} =
             #       asyncCheck cleanupChann(m, channel, initiator))
 
             asyncCheck m.streamHandler(stream)
-
             continue
         of MessageType.MsgIn, MessageType.MsgOut:
           trace "pushing data to channel", id = id,
@@ -145,8 +141,10 @@ proc newMplex*(conn: Connection,
   .addCallback do (udata: pointer):
     trace "connection closed, cleaning up mplex"
     asyncCheck m.close()
-    
-method newStream*(m: Mplex, name: string = "", lazy: bool = false): Future[Connection] {.async, gcsafe.} =
+
+method newStream*(m: Mplex,
+                  name: string = "",
+                  lazy: bool = false): Future[Connection] {.async, gcsafe.} =
   let channel = await m.newStreamInternal(lazy = lazy)
   if not lazy:
     await channel.open()