refactor(cbindings): Thread-safe communication between the main thread and the Waku Thread (#1978)

* Thread-safe comms between main thread & Waku Thread - ChannelSPSCSingle. * Renaming procs from 'new' to 'createShared'. They use the shared allocator. * peer_manager_request: no need to use ptr WakuNode. * waku_thread: moving the 'waitFor' to upper layer. * waku_thread: `poll()` -> `waitFor sleepAsync(1)` to avoid risk of blocking. * libwaku: thread-safe "sub-objects" in an inter-thread requests. When two threads send data each other, that data cannot contain any GC'ed type (string, seq, ref, closures) at any level. * Allocating the 'configJson' in main thread and deallocating in Waku Thread.
2023-09-18 09:21:50 +02:00 · 2023-09-18 09:21:50 +02:00 · 72f90663cd
parent 2e515a06ed
commit 72f90663cd
12 changed files with 378 additions and 166 deletions
--- a/.gitmodules
+++ b/.gitmodules
@ -154,3 +154,8 @@
 	url = https://github.com/nitely/nim-unicodedb.git
 	ignore = untracked
 	branch = master
+[submodule "vendor/nim-taskpools"]
+	path = vendor/nim-taskpools
+	url = https://github.com/status-im/nim-taskpools.git
+	ignore = untracked
+	branch = stable
--- a/library/alloc.nim
+++ b/library/alloc.nim
@ -1,3 +1,5 @@
+## Can be shared safely between threads
+type SharedSeq*[T] = tuple[data: ptr UncheckedArray[T], len: int]

 proc alloc*(str: cstring): cstring =
  # Byte allocation from the given address.
@ -5,3 +7,30 @@ proc alloc*(str: cstring): cstring =
  let ret = cast[cstring](allocShared(len(str) + 1))
  copyMem(ret, str, len(str) + 1)
  return ret
+
+proc alloc*(str: string): cstring =
+  ## Byte allocation from the given address.
+  ## There should be the corresponding manual deallocation with deallocShared !
+  var ret = cast[cstring](allocShared(str.len + 1))
+  let s = cast[seq[char]](str)
+  for i in 0..<str.len:
+    ret[i] = s[i]
+  ret[str.len] = '\0'
+  return ret
+
+proc allocSharedSeq*[T](s: seq[T]): SharedSeq[T] =
+  let data = cast[ptr T](allocShared(s.len))
+  copyMem(data, unsafeAddr s, s.len)
+  return (cast[ptr UncheckedArray[T]](data), s.len)
+
+proc deallocSharedSeq*[T](s: var SharedSeq[T]) =
+  deallocShared(s.data)
+  s.len = 0
+
+proc toSeq*[T](s: SharedSeq[T]): seq[T] =
+  ## Creates a seq[T] from a SharedSeq[T]. No explicit dealloc is required
+  ## as req[T] is a GC managed type.
+  var ret = newSeq[T]()
+  for i in 0..<s.len:
+    ret.add(s.data[i])
+  return ret
--- a/library/libwaku.nim
+++ b/library/libwaku.nim
@ -16,9 +16,10 @@ import
  ../../../waku/waku_relay/protocol,
  ./events/json_message_event,
  ./waku_thread/waku_thread,
-  ./waku_thread/inter_thread_communication/node_lifecycle_request,
-  ./waku_thread/inter_thread_communication/peer_manager_request,
-  ./waku_thread/inter_thread_communication/protocols/relay_request,
+  ./waku_thread/inter_thread_communication/requests/node_lifecycle_request,
+  ./waku_thread/inter_thread_communication/requests/peer_manager_request,
+  ./waku_thread/inter_thread_communication/requests/protocols/relay_request,
+  ./waku_thread/inter_thread_communication/waku_thread_request,
  ./alloc

 ################################################################################
@ -79,7 +80,8 @@ proc waku_new(configJson: cstring,
    return RET_ERR

  let sendReqRes = waku_thread.sendRequestToWakuThread(
-                                NodeLifecycleRequest.new(
+                                      RequestType.LIFECYCLE,
+                                      NodeLifecycleRequest.createShared(
                                              NodeLifecycleMsgType.CREATE_NODE,
                                              configJson))
  if sendReqRes.isErr():
@ -199,7 +201,8 @@ proc waku_relay_publish(pubSubTopic: cstring,
                            $pst

  let sendReqRes = waku_thread.sendRequestToWakuThread(
-                        RelayRequest.new(RelayMsgType.PUBLISH,
+                          RequestType.RELAY,
+                          RelayRequest.createShared(RelayMsgType.PUBLISH,
                                          PubsubTopic($pst),
                                          WakuRelayHandler(relayEventCallback),
                                          wakuMessage))
@ -214,12 +217,14 @@ proc waku_relay_publish(pubSubTopic: cstring,

 proc waku_start() {.dynlib, exportc.} =
  discard waku_thread.sendRequestToWakuThread(
-                                NodeLifecycleRequest.new(
+                                      RequestType.LIFECYCLE,
+                                      NodeLifecycleRequest.createShared(
                                              NodeLifecycleMsgType.START_NODE))

 proc waku_stop() {.dynlib, exportc.} =
  discard waku_thread.sendRequestToWakuThread(
-                                NodeLifecycleRequest.new(
+                                      RequestType.LIFECYCLE,
+                                      NodeLifecycleRequest.createShared(
                                              NodeLifecycleMsgType.STOP_NODE))

 proc waku_relay_subscribe(
@ -228,8 +233,10 @@ proc waku_relay_subscribe(
                {.dynlib, exportc.} =

  let pst = pubSubTopic.alloc()
+
  let sendReqRes = waku_thread.sendRequestToWakuThread(
-                        RelayRequest.new(RelayMsgType.SUBSCRIBE,
+                              RequestType.RELAY,
+                              RelayRequest.createShared(RelayMsgType.SUBSCRIBE,
                                    PubsubTopic($pst),
                                    WakuRelayHandler(relayEventCallback)))
  deallocShared(pst)
@ -247,8 +254,10 @@ proc waku_relay_unsubscribe(
                {.dynlib, exportc.} =

  let pst = pubSubTopic.alloc()
+
  let sendReqRes = waku_thread.sendRequestToWakuThread(
-                        RelayRequest.new(RelayMsgType.UNSUBSCRIBE,
+                              RequestType.RELAY,
+                              RelayRequest.createShared(RelayMsgType.SUBSCRIBE,
                                    PubsubTopic($pst),
                                    WakuRelayHandler(relayEventCallback)))
  deallocShared(pst)
@ -266,7 +275,8 @@ proc waku_connect(peerMultiAddr: cstring,
                  {.dynlib, exportc.} =

  let connRes = waku_thread.sendRequestToWakuThread(
-                                  PeerManagementRequest.new(
+                                   RequestType.PEER_MANAGER,
+                                   PeerManagementRequest.createShared(
                                            PeerManagementMsgType.CONNECT_TO,
                                            $peerMultiAddr,
                                            chronos.milliseconds(timeoutMs)))
--- a/library/waku_thread/inter_thread_communication/protocols/relay_request.nim
+++ b/library/waku_thread/inter_thread_communication/protocols/relay_request.nim
@ -1,64 +0,0 @@
-
-import
-  std/[options,sequtils,strutils]
-import
-  chronicles,
-  chronos,
-  stew/results,
-  stew/shims/net
-import
-  ../../../../waku/waku_core/message/message,
-  ../../../../waku/node/waku_node,
-  ../../../../waku/waku_core/topics/pubsub_topic,
-  ../../../../waku/waku_relay/protocol,
-  ../request
-
-type
-  RelayMsgType* = enum
-    SUBSCRIBE
-    UNSUBSCRIBE
-    PUBLISH
-
-type
-  RelayRequest* = ref object of InterThreadRequest
-    operation: RelayMsgType
-    pubsubTopic: PubsubTopic
-    relayEventCallback: WakuRelayHandler # not used in 'PUBLISH' requests
-    message: WakuMessage # this field is only used in 'PUBLISH' requests
-
-proc new*(T: type RelayRequest,
-          op: RelayMsgType,
-          pubsubTopic: PubsubTopic,
-          relayEventCallback: WakuRelayHandler = nil,
-          message = WakuMessage()): T =
-
-  return RelayRequest(operation: op,
-                      pubsubTopic: pubsubTopic,
-                      relayEventCallback: relayEventCallback,
-                      message: message)
-
-method process*(self: RelayRequest,
-                node: ptr WakuNode): Future[Result[string, string]] {.async.} =
-
-  if node.wakuRelay.isNil():
-    return err("Operation not supported without Waku Relay enabled.")
-
-  case self.operation:
-
-    of SUBSCRIBE:
-      node.wakuRelay.subscribe(self.pubsubTopic, self.relayEventCallback)
-
-    of UNSUBSCRIBE:
-      node.wakuRelay.unsubscribe(self.pubsubTopic)
-
-    of PUBLISH:
-      let numPeers = await node.wakuRelay.publish(self.pubsubTopic,
-                                                  self.message)
-      if numPeers == 0:
-        return err("Message not sent because no peers found.")
-
-      elif numPeers > 0:
-        # TODO: pending to return a valid message Id
-        return ok("hard-coded-message-id")
-
-  return ok("")
--- a/library/waku_thread/inter_thread_communication/request.nim
+++ b/library/waku_thread/inter_thread_communication/request.nim
@ -1,21 +0,0 @@
-
-# This file contains the base message request type that will be handled
-# by the Waku Node thread.
-
-import
-  std/json,
-  stew/results
-import
-  chronos
-import
-  ../../../waku/node/waku_node,
-  ../waku_thread
-
-type
-  InterThreadRequest* = ref object of RootObj
-
-method process*(self: InterThreadRequest, node: ptr WakuNode):
-                Future[Result[string, string]] {.base.} = discard
-
-proc `$`*(self: InterThreadRequest): string =
-  return $( %* self )
--- a/library/waku_thread/inter_thread_communication/requests/node_lifecycle_request.nim
+++ b/library/waku_thread/inter_thread_communication/requests/node_lifecycle_request.nim
@ -6,21 +6,21 @@ import
  stew/results,
  stew/shims/net
 import
-  ../../../waku/common/enr/builder,
-  ../../../waku/waku_enr/capabilities,
-  ../../../waku/waku_enr/multiaddr,
-  ../../../waku/waku_enr/sharding,
-  ../../../waku/waku_core/message/message,
-  ../../../waku/waku_core/topics/pubsub_topic,
-  ../../../waku/node/peer_manager/peer_manager,
-  ../../../waku/waku_core,
-  ../../../waku/node/waku_node,
-  ../../../waku/node/builder,
-  ../../../waku/node/config,
-  ../../../waku/waku_relay/protocol,
-  ../../events/[json_error_event,json_message_event,json_base_event],
-  ../config,
-  ./request
+  ../../../../waku/common/enr/builder,
+  ../../../../waku/waku_enr/capabilities,
+  ../../../../waku/waku_enr/multiaddr,
+  ../../../../waku/waku_enr/sharding,
+  ../../../../waku/waku_core/message/message,
+  ../../../../waku/waku_core/topics/pubsub_topic,
+  ../../../../waku/node/peer_manager/peer_manager,
+  ../../../../waku/waku_core,
+  ../../../../waku/node/waku_node,
+  ../../../../waku/node/builder,
+  ../../../../waku/node/config,
+  ../../../../waku/waku_relay/protocol,
+  ../../../events/[json_error_event,json_message_event,json_base_event],
+  ../../../alloc,
+  ../../config

 type
  NodeLifecycleMsgType* = enum
@ -29,15 +29,22 @@ type
    STOP_NODE

 type
-  NodeLifecycleRequest* = ref object of InterThreadRequest
+  NodeLifecycleRequest* = object
    operation: NodeLifecycleMsgType
    configJson: cstring ## Only used in 'CREATE_NODE' operation

-proc new*(T: type NodeLifecycleRequest,
+proc createShared*(T: type NodeLifecycleRequest,
                   op: NodeLifecycleMsgType,
-          configJson: cstring = ""): T =
+                   configJson: cstring = ""): ptr type T =

-  return NodeLifecycleRequest(operation: op, configJson: configJson)
+  var ret = createShared(T)
+  ret[].operation = op
+  ret[].configJson = configJson.alloc()
+  return ret
+
+proc destroyShared(self: ptr NodeLifecycleRequest) =
+  deallocShared(self[].configJson)
+  deallocShared(self)

 proc createNode(configJson: cstring):
                Future[Result[WakuNode, string]] {.async.} =
@ -108,9 +115,11 @@ proc createNode(configJson: cstring):

  return ok(newNode)

-method process*(self: NodeLifecycleRequest,
+proc process*(self: ptr NodeLifecycleRequest,
              node: ptr WakuNode): Future[Result[string, string]] {.async.} =

+  defer: destroyShared(self)
+
  case self.operation:
    of CREATE_NODE:
      let newNodeRes = await createNode(self.configJson)
--- a/library/waku_thread/inter_thread_communication/requests/peer_manager_request.nim
+++ b/library/waku_thread/inter_thread_communication/requests/peer_manager_request.nim
@ -7,27 +7,33 @@ import
  stew/results,
  stew/shims/net
 import
-  ../../../waku/node/waku_node,
-  ./request
+  ../../../../waku/node/waku_node,
+  ../../../alloc

 type
  PeerManagementMsgType* = enum
    CONNECT_TO

 type
-  PeerManagementRequest* = ref object of InterThreadRequest
+  PeerManagementRequest* = object
    operation: PeerManagementMsgType
-    peerMultiAddr: string
+    peerMultiAddr: cstring
    dialTimeout: Duration

-proc new*(T: type PeerManagementRequest,
+proc createShared*(T: type PeerManagementRequest,
                   op: PeerManagementMsgType,
                   peerMultiAddr: string,
-          dialTimeout: Duration): T =
+                   dialTimeout: Duration): ptr type T =

-  return PeerManagementRequest(operation: op,
-                               peerMultiAddr: peerMultiAddr,
-                               dialTimeout: dialTimeout)
+  var ret = createShared(T)
+  ret[].operation = op
+  ret[].peerMultiAddr = peerMultiAddr.alloc()
+  ret[].dialTimeout = dialTimeout
+  return ret
+
+proc destroyShared(self: ptr PeerManagementRequest) =
+  deallocShared(self[].peerMultiAddr)
+  deallocShared(self)

 proc connectTo(node: WakuNode,
               peerMultiAddr: string,
@ -46,13 +52,15 @@ proc connectTo(node: WakuNode,

  return ok()

-method process*(self: PeerManagementRequest,
-                node: ptr WakuNode): Future[Result[string, string]] {.async.} =
+proc process*(self: ptr PeerManagementRequest,
+              node: WakuNode): Future[Result[string, string]] {.async.} =
+
+  defer: destroyShared(self)

  case self.operation:

    of CONNECT_TO:
-      let ret = node[].connectTo(self.peerMultiAddr, self.dialTimeout)
+      let ret = node.connectTo($self[].peerMultiAddr, self[].dialTimeout)
      if ret.isErr():
        return err(ret.error)

--- a/library/waku_thread/inter_thread_communication/requests/protocols/relay_request.nim
+++ b/library/waku_thread/inter_thread_communication/requests/protocols/relay_request.nim
@ -0,0 +1,114 @@
+
+import
+  std/[options,sequtils,strutils]
+import
+  chronicles,
+  chronos,
+  stew/results,
+  stew/shims/net
+import
+  ../../../../../waku/waku_core/message/message,
+  ../../../../../waku/node/waku_node,
+  ../../../../../waku/waku_core/time, # Timestamp
+  ../../../../../waku/waku_core/topics/pubsub_topic,
+  ../../../../../waku/waku_relay/protocol,
+  ../../../../alloc
+
+type
+  RelayMsgType* = enum
+    SUBSCRIBE
+    UNSUBSCRIBE
+    PUBLISH
+
+type
+  ThreadSafeWakuMessage* = object
+    payload: SharedSeq[byte]
+    contentTopic: cstring
+    meta: SharedSeq[byte]
+    version: uint32
+    timestamp: Timestamp
+    ephemeral: bool
+    when defined(rln):
+      proof: SharedSeq[byte]
+
+type
+  RelayRequest* = object
+    operation: RelayMsgType
+    pubsubTopic: cstring
+    relayEventCallback: WakuRelayHandler # not used in 'PUBLISH' requests
+    message: ThreadSafeWakuMessage # only used in 'PUBLISH' requests
+
+proc createShared*(T: type RelayRequest,
+                   op: RelayMsgType,
+                   pubsubTopic: PubsubTopic,
+                   relayEventCallback: WakuRelayHandler = nil,
+                   m = WakuMessage()): ptr type T =
+
+  var ret = createShared(T)
+  ret[].operation = op
+  ret[].pubsubTopic = pubsubTopic.alloc()
+  ret[].relayEventCallback = relayEventCallback
+  ret[].message = ThreadSafeWakuMessage(
+                                payload: allocSharedSeq(m.payload),
+                                contentTopic: m.contentTopic.alloc(),
+                                meta: allocSharedSeq(m.meta),
+                                version: m.version,
+                                timestamp: m.timestamp,
+                                ephemeral: m.ephemeral,
+                            )
+  when defined(rln):
+    ret[].message.proof = allocSharedSeq(m.proof)
+
+  return ret
+
+proc destroyShared(self: ptr RelayRequest) =
+  deallocSharedSeq(self[].message.payload)
+  deallocShared(self[].message.contentTopic)
+  deallocSharedSeq(self[].message.meta)
+  when defined(rln):
+    deallocSharedSeq(self[].message.proof)
+
+  deallocShared(self)
+
+proc toWakuMessage(m: ThreadSafeWakuMessage): WakuMessage =
+  var wakuMessage = WakuMessage()
+
+  wakuMessage.payload = m.payload.toSeq()
+  wakuMessage.contentTopic = $m.contentTopic
+  wakuMessage.meta = m.meta.toSeq()
+  wakuMessage.version = m.version
+  wakuMessage.timestamp = m.timestamp
+  wakuMessage.ephemeral = m.ephemeral
+
+  when defined(rln):
+    wakuMessage.proof = m.proof
+
+  return wakuMessage
+
+proc process*(self: ptr RelayRequest,
+              node: ptr WakuNode): Future[Result[string, string]] {.async.} =
+
+  defer: destroyShared(self)
+
+  if node.wakuRelay.isNil():
+    return err("Operation not supported without Waku Relay enabled.")
+
+  case self.operation:
+
+    of SUBSCRIBE:
+      node.wakuRelay.subscribe($self.pubsubTopic, self.relayEventCallback)
+
+    of UNSUBSCRIBE:
+      node.wakuRelay.unsubscribe($self.pubsubTopic)
+
+    of PUBLISH:
+      let numPeers = await node.wakuRelay.publish($self.pubsubTopic,
+                                                  self.message.toWakuMessage())
+      if numPeers == 0:
+        return err("Message not sent because no peers found.")
+
+      elif numPeers > 0:
+        # TODO: pending to return a valid message Id
+        return ok("hard-coded-message-id")
+
+  return ok("")
--- a/library/waku_thread/inter_thread_communication/waku_thread_request.nim
+++ b/library/waku_thread/inter_thread_communication/waku_thread_request.nim
@ -0,0 +1,57 @@
+
+## This file contains the base message request type that will be handled.
+## The requests are created by the main thread and processed by
+## the Waku Thread.
+
+import
+  std/json,
+  stew/results
+import
+  chronos
+import
+  ../../../waku/node/waku_node,
+  ./requests/node_lifecycle_request,
+  ./requests/peer_manager_request,
+  ./requests/protocols/relay_request
+
+type
+  RequestType* {.pure.} = enum
+    LIFECYCLE,
+    PEER_MANAGER,
+    RELAY,
+
+type
+  InterThreadRequest* = object
+    reqType: RequestType
+    reqContent: pointer
+
+proc createShared*(T: type InterThreadRequest,
+                   reqType: RequestType,
+                   reqContent: pointer): ptr type T =
+  var ret = createShared(T)
+  ret[].reqType = reqType
+  ret[].reqContent = reqContent
+  return ret
+
+proc process*(T: type InterThreadRequest,
+              request: ptr InterThreadRequest,
+              node: ptr WakuNode):
+              Future[Result[string, string]] {.async.} =
+  ## Processes the request and deallocates its memory
+  defer: deallocShared(request)
+
+  echo "Request received: " & $request[].reqType
+
+  let retFut =
+    case request[].reqType
+      of LIFECYCLE:
+        cast[ptr NodeLifecycleRequest](request[].reqContent).process(node)
+      of PEER_MANAGER:
+        cast[ptr PeerManagementRequest](request[].reqContent).process(node[])
+      of RELAY:
+        cast[ptr RelayRequest](request[].reqContent).process(node)
+
+  return await retFut
+
+proc `$`*(self: InterThreadRequest): string =
+  return $self.reqType
--- a/library/waku_thread/inter_thread_communication/waku_thread_response.nim
+++ b/library/waku_thread/inter_thread_communication/waku_thread_response.nim
@ -0,0 +1,53 @@
+
+## This file contains the base message response type that will be handled.
+## The response will be created from the Waku Thread and processed in
+## the main thread.
+
+import
+  std/json,
+  stew/results
+
+type
+  ResponseType {.pure.} = enum
+    OK,
+    ERR,
+
+type
+  InterThreadResponse* = object
+    respType: ResponseType
+    content: cstring
+
+proc createShared*(T: type InterThreadResponse,
+                   res: Result[string, string]): ptr type T =
+  ## Converts a `Result[string, string]` into a `ptr InterThreadResponse`
+  ## so that it can be transfered to another thread in a safe way.
+
+  var ret = createShared(T)
+  if res.isOk():
+    let value = res.get()
+    ret[].respType = ResponseType.OK
+    ret[].content = cast[cstring](allocShared0(value.len + 1))
+    copyMem(ret[].content, unsafeAddr value, value.len + 1)
+  else:
+    let error = res.error
+    ret[].respType = ResponseType.ERR
+    ret[].content = cast[cstring](allocShared0(error.len + 1))
+    copyMem(ret[].content, unsafeAddr error, error.len + 1)
+  return ret
+
+proc process*(T: type InterThreadResponse,
+              resp: ptr InterThreadResponse):
+              Result[string, string] =
+  ## Converts the received `ptr InterThreadResponse` into a
+  ## `Result[string, string]`. Notice that the response is expected to be
+  ## allocated from the Waku Thread and deallocated by the main thread.
+
+  defer:
+    deallocShared(resp[].content)
+    deallocShared(resp)
+
+  case resp[].respType
+    of OK:
+      return ok($resp[].content)
+    of ERR:
+      return err($resp[].content)
--- a/library/waku_thread/waku_thread.nim
+++ b/library/waku_thread/waku_thread.nim
@ -9,18 +9,19 @@ import
  chronicles,
  chronos,
  stew/results,
-  stew/shims/net
+  stew/shims/net,
+  taskpools/channels_spsc_single
 import
  ../../../waku/node/waku_node,
  ../events/[json_error_event,json_message_event,json_base_event],
-  ./inter_thread_communication/request
+  ./inter_thread_communication/waku_thread_request,
+  ./inter_thread_communication/waku_thread_response

 type
  Context* = object
    thread: Thread[(ptr Context)]
-    reqChannel: Channel[InterThreadRequest]
-    respChannel: Channel[Result[string, string]]
-    node: WakuNode
+    reqChannel: ChannelSPSCSingle[ptr InterThreadRequest]
+    respChannel: ChannelSPSCSingle[ptr InterThreadResponse]

 var ctx {.threadvar.}: ptr Context

@ -49,12 +50,20 @@ proc run(ctx: ptr Context) {.thread.} =

  while running.load == true:
    ## Trying to get a request from the libwaku main thread
-    let req = ctx.reqChannel.tryRecv()
-    if req[0] == true:
-      let response = waitFor req[1].process(addr node)
-      ctx.respChannel.send( response )

-    poll()
+    var request: ptr InterThreadRequest
+    let recvOk = ctx.reqChannel.tryRecv(request)
+    if recvOk == true:
+      let resultResponse =
+        waitFor InterThreadRequest.process(request, addr node)
+
+      ## Converting a `Result` into a thread-safe transferable response type
+      let threadSafeResp = InterThreadResponse.createShared(resultResponse)
+
+      ## The error-handling is performed in the main thread
+      discard ctx.respChannel.trySend( threadSafeResp )
+
+    waitFor sleepAsync(1)

  tearDownForeignThreadGc()

@ -65,8 +74,6 @@ proc createWakuThread*(): Result[void, string] =
  waku_init()

  ctx = createShared(Context, 1)
-  ctx.reqChannel.open()
-  ctx.respChannel.open()

  running.store(true)

@ -83,20 +90,24 @@ proc createWakuThread*(): Result[void, string] =
 proc stopWakuNodeThread*() =
  running.store(false)
  joinThread(ctx.thread)
-
-  ctx.reqChannel.close()
-  ctx.respChannel.close()
-
  freeShared(ctx)

-proc sendRequestToWakuThread*(req: InterThreadRequest): Result[string, string] =
+proc sendRequestToWakuThread*(reqType: RequestType,
+                              reqContent: pointer): Result[string, string] =

-  ctx.reqChannel.send(req)
+  let req = InterThreadRequest.createShared(reqType, reqContent)

-  var resp = ctx.respChannel.tryRecv()
-  while resp[0] == false:
-    resp = ctx.respChannel.tryRecv()
+  ## Sending the request
+  let sentOk = ctx.reqChannel.trySend(req)
+  if not sentOk:
+    return err("Couldn't send a request to the waku thread: " & $req[])
+
+  ## Waiting for the response
+  var response: ptr InterThreadResponse
+  var recvOk = ctx.respChannel.tryRecv(response)
+  while recvOk == false:
+    recvOk = ctx.respChannel.tryRecv(response)
    os.sleep(1)

-  return resp[1]
-
+  ## Converting the thread-safe response into a managed/CG'ed `Result`
+  return InterThreadResponse.process(response)
--- a/vendor/nim-taskpools
+++ b/vendor/nim-taskpools
@ -0,0 +1 @@
+Subproject commit 15e23ef1cf0860330dcc32f50fcce5f840031e28
				`@ -0,0 +1 @@`
				`Subproject commit 15e23ef1cf0860330dcc32f50fcce5f840031e28`