From a492e3c21858a1eff66fc2bb7a130542646eb1d6 Mon Sep 17 00:00:00 2001
From: Zahary Karadjov <zahary@gmail.com>
Date: Mon, 3 Jun 2019 20:05:45 +0300
Subject: [PATCH] More flexible definitions of Responders

---
 eth/p2p/p2p_backends_helpers.nim |  5 +++++
 eth/p2p/p2p_protocol_dsl.nim     | 33 +++++++++++++++++++-------------
 eth/p2p/rlpx.nim                 | 10 +++++++++-
 3 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/eth/p2p/p2p_backends_helpers.nim b/eth/p2p/p2p_backends_helpers.nim
index c731d47..2ffb862 100644
--- a/eth/p2p/p2p_backends_helpers.nim
+++ b/eth/p2p/p2p_backends_helpers.nim
@@ -23,6 +23,11 @@ template networkState*(connection: Peer, Protocol: type): untyped =
 
 proc initProtocolState*[T](state: T, x: Peer|EthereumNode) {.gcsafe.} = discard
 
+proc resolveFuture[MsgType](msg: pointer, future: FutureBase) {.gcsafe.} =
+  var f = Future[MsgType](future)
+  doAssert(not f.finished())
+  f.complete(cast[ptr MsgType](msg)[])
+
 proc requestResolver[MsgType](msg: pointer, future: FutureBase) {.gcsafe.} =
   var f = Future[Option[MsgType]](future)
   if not f.finished:
diff --git a/eth/p2p/p2p_protocol_dsl.nim b/eth/p2p/p2p_protocol_dsl.nim
index cca7d09..3c3d2f6 100644
--- a/eth/p2p/p2p_protocol_dsl.nim
+++ b/eth/p2p/p2p_protocol_dsl.nim
@@ -17,9 +17,10 @@ type
     timeoutParam*: NimNode
     recIdent*: NimNode
     recBody*: NimNode
-    userHandler*: NimNode
     protocol*: P2PProtocol
     response*: Message
+    userHandler*: NimNode
+    initResponderCall*: NimNode
 
   Request* = ref object
     queries*: seq[Message]
@@ -93,6 +94,7 @@ type
     # Code generators
     implementMsg*: proc (msg: Message)
     implementProtocolInit*: proc (protocol: P2PProtocol): NimNode
+
     afterProtocolInit*: proc (protocol: P2PProtocol)
 
     # Bound symbols to the back-end run-time types and procs
@@ -213,6 +215,9 @@ proc init*(T: type P2PProtocol, backendFactory: BackendFactory,
     outProcRegistrations: newStmtList())
 
   result.backend = backendFactory(result)
+  assert(not result.backend.implementProtocolInit.isNil)
+  assert(not result.backend.ResponderType.isNil)
+
   result.processProtocolBody body
 
   if not result.backend.afterProtocolInit.isNil:
@@ -312,6 +317,11 @@ proc ensureTimeoutParam(procDef: NimNode, timeouts: int64): NimNode =
 proc hasReqId*(msg: Message): bool =
   msg.protocol.useRequestIds and msg.kind in {msgRequest, msgResponse}
 
+proc ResponderType(msg: Message): NimNode =
+  var resp = if msg.kind == msgRequest: msg.response else: msg
+  newTree(nnkBracketExpr,
+          msg.protocol.backend.ResponderType, resp.recIdent)
+
 proc newMsg(protocol: P2PProtocol, kind: MessageKind, id: int,
             procDef: NimNode, timeoutParam: NimNode = nil,
             response: Message = nil): Message =
@@ -354,16 +364,16 @@ proc newMsg(protocol: P2PProtocol, kind: MessageKind, id: int,
       assert response != nil
       let
         peerParam = userHandler.params[1][0]
-        ResponderType = protocol.backend.ResponderType
-        ResponseRecord = response.recIdent
+        ResponderType = result.ResponderType
+        initResponderCall = newCall(ident"init", ResponderType, peerParam)
 
       if protocol.useRequestIds:
-        userHandler.addPreludeDefs quote do:
-          let `responseVar` = `ResponderType`[`ResponseRecord`](peer: `peerParam`,
-                                                                reqId: `reqIdVar`)
-      else:
-        userHandler.addPreludeDefs quote do:
-          let `responseVar` = `ResponderType`[`ResponseRecord`](peer: `peerParam`)
+        initResponderCall.add reqIdVar
+
+      userHandler.addPreludeDefs quote do:
+        let `responseVar` = `initResponderCall`
+
+      result.initResponderCall = initResponderCall
 
     protocol.outRecvProcs.add userHandler
     result.userHandler = userHandler
@@ -418,12 +428,9 @@ proc createSendProc*(msg: Message,
     # 1 to the correct strongly-typed ResponderType. The incoming procs still
     # gets the normal Peer paramter.
     let
-      ResponderTypeHead = msg.protocol.backend.ResponderType
-      ResponderType = newTree(nnkBracketExpr, ResponderTypeHead, msg.recIdent)
+      ResponderType = msg.ResponderType
       sendProcName = msg.ident
 
-    assert ResponderTypeHead != nil
-
     def[3][1][1] = ResponderType
 
     # We create a helper that enables the `response.send()` syntax
diff --git a/eth/p2p/rlpx.nim b/eth/p2p/rlpx.nim
index 742d2e5..e786900 100644
--- a/eth/p2p/rlpx.nim
+++ b/eth/p2p/rlpx.nim
@@ -45,9 +45,17 @@ var
 template allProtocols*: auto = {.gcsafe.}: gProtocols
 template devp2pInfo: auto = {.gcsafe.}: gDevp2pInfo
 
+proc init*[MsgName](T: type ResponderWithId[MsgName],
+                    peer: Peer, reqId: int): T =
+  T(peer: peer, reqId: reqId)
+
+proc init*[MsgName](T: type ResponderWithoutId[MsgName], peer: Peer): T =
+  T(peer)
+
 chronicles.formatIt(Peer): $(it.remote)
 
-proc disconnect*(peer: Peer, reason: DisconnectionReason, notifyOtherPeer = false) {.gcsafe, async.}
+proc disconnect*(peer: Peer, reason: DisconnectionReason,
+                 notifyOtherPeer = false) {.gcsafe, async.}
 
 template raisePeerDisconnected(msg: string, r: DisconnectionReason) =
   var e = newException(PeerDisconnected, msg)