waku_thread.nim: Using 'ThreadSignalPtr' instead of loop to handle req/resp (#2045)

library/waku_thread/waku_thread.nim

@@ -8,9 +8,10 @@ import
 import
   chronicles,
   chronos,
+  chronos/threadsync,
+  taskpools/channels_spsc_single,
   stew/results,
-  stew/shims/net,
-  taskpools/channels_spsc_single
+  stew/shims/net
 import
   ../../../waku/node/waku_node,
   ../events/[json_error_event,json_message_event,json_base_event],
@@ -21,7 +22,9 @@ type
   Context* = object
     thread: Thread[(ptr Context)]
     reqChannel: ChannelSPSCSingle[ptr InterThreadRequest]
+    reqSignal: ThreadSignalPtr
     respChannel: ChannelSPSCSingle[ptr InterThreadResponse]
+    respSignal: ThreadSignalPtr
 
 var ctx {.threadvar.}: ptr Context
 
@@ -52,6 +55,7 @@ proc run(ctx: ptr Context) {.thread.} =
     ## Trying to get a request from the libwaku main thread
 
     var request: ptr InterThreadRequest
+    waitFor ctx.reqSignal.wait()
     let recvOk = ctx.reqChannel.tryRecv(request)
     if recvOk == true:
       let resultResponse =
@@ -61,9 +65,8 @@ proc run(ctx: ptr Context) {.thread.} =
       let threadSafeResp = InterThreadResponse.createShared(resultResponse)
 
       ## The error-handling is performed in the main thread
-      discard ctx.respChannel.trySend( threadSafeResp )
-
-    waitFor sleepAsync(1)
+      discard ctx.respChannel.trySend(threadSafeResp)
+      discard ctx.respSignal.fireSync()
 
   tearDownForeignThreadGc()
 
@@ -74,6 +77,10 @@ proc createWakuThread*(): Result[void, string] =
   waku_init()
 
   ctx = createShared(Context, 1)
+  ctx.reqSignal = ThreadSignalPtr.new().valueOr:
+    return err("couldn't create reqSignal ThreadSignalPtr")
+  ctx.respSignal = ThreadSignalPtr.new().valueOr:
+    return err("couldn't create respSignal ThreadSignalPtr")
 
   running.store(true)
 
@@ -90,6 +97,8 @@ proc createWakuThread*(): Result[void, string] =
 proc stopWakuNodeThread*() =
   running.store(false)
   joinThread(ctx.thread)
+  discard ctx.reqSignal.close()
+  discard ctx.respSignal.close()
   freeShared(ctx)
 
 proc sendRequestToWakuThread*(reqType: RequestType,
@@ -102,12 +111,20 @@ proc sendRequestToWakuThread*(reqType: RequestType,
   if not sentOk:
     return err("Couldn't send a request to the waku thread: " & $req[])
 
+  let fireSyncRes = ctx.reqSignal.fireSync()
+  if fireSyncRes.isErr():
+    return err("failed fireSync: " & $fireSyncRes.error)
+
+  if fireSyncRes.get() == false:
+    return err("Couldn't fireSync in time")
+
   ## Waiting for the response
+  waitFor ctx.respSignal.wait()
+
   var response: ptr InterThreadResponse
   var recvOk = ctx.respChannel.tryRecv(response)
-  while recvOk == false:
-    recvOk = ctx.respChannel.tryRecv(response)
-    os.sleep(1)
+  if recvOk == false:
+    return err("Couldn't receive response from the waku thread: " & $req[])
 
   ## Converting the thread-safe response into a managed/CG'ed `Result`
   return InterThreadResponse.process(response)