From 0a4fb24b9fce694a85328060f2f4804a45398df4 Mon Sep 17 00:00:00 2001
From: Alex Hultman <alexhultman@gmail.com>
Date: Fri, 1 Mar 2019 19:47:27 +0100
Subject: [PATCH] Majorly simplify process.nextTick

---
 src/addon.cpp | 52 +--------------------------------------------------
 src/uws.js    | 10 +---------
 2 files changed, 2 insertions(+), 60 deletions(-)

diff --git a/src/addon.cpp b/src/addon.cpp
index 499e68c..10db94e 100644
--- a/src/addon.cpp
+++ b/src/addon.cpp
@@ -24,13 +24,6 @@
 using namespace v8;
 
 /* These two are definitely static */
-
-/* Warning: having nextTickQueue items at loop fallthrough is not allowed.
- * Process will crash/hang due to destruction of V8 resouces after V8 itself
- * has been destroyed. Either enforce nextTick calls to keep the loop rolling
- * via for instance setTimeout or setImmediate, or make sure to drain completely
- * the queue at process.on('beforeExit'). */
-std::vector<UniquePersistent<Function>> nextTickQueue;
 Isolate *isolate;
 
 #include "Utilities.h"
@@ -39,43 +32,12 @@ Isolate *isolate;
 #include "HttpRequestWrapper.h"
 #include "AppWrapper.h"
 
-/* We are not compatible with Node.js nextTick for performance (and standalone) reasons */
-void nextTick(const FunctionCallbackInfo<Value> &args) {
-    nextTickQueue.emplace_back(UniquePersistent<Function>(isolate, Local<Function>::Cast(args[0])));
-}
-
 /* Used for debugging */
 void print(const FunctionCallbackInfo<Value> &args) {
     NativeString nativeString(isolate, args[0]);
     std::cout << nativeString.getString() << std::endl;
 }
 
-/* Does not guarantee empty queue because of recursive nextTick calls.
- * Should return int queueSize after calling queued items, so that
- * proper while(processNextTickQueueImpl()) can be done */
-int processNextTickQueueImpl(Isolate *isolate) {
-
-    /* Run async continuations, promises and other V8-queued tasks */
-    isolate->RunMicrotasks();
-
-    if (nextTickQueue.size()) {
-        /* Swap queues for recursive calls */
-        std::vector<UniquePersistent<Function>> currentNextTickQueue = std::move(nextTickQueue);
-
-        HandleScope hs(isolate);
-        for (UniquePersistent<Function> &f : currentNextTickQueue) {
-            Local<Function>::New(isolate, f)->Call(isolate->GetCurrentContext()->Global(), 0, nullptr);
-        }
-    }
-
-    return nextTickQueue.size();
-}
-
-/* It is possible to call this at process.beforeExit until it returns 0. */
-void processNextTickQueue(const FunctionCallbackInfo<Value> &args) {
-    args.GetReturnValue().Set(Integer::New(isolate, processNextTickQueueImpl(isolate)));
-}
-
 /* todo: Put this function and all inits of it in its own header */
 void uWS_us_listen_socket_close(const FunctionCallbackInfo<Value> &args) {
     us_listen_socket_close((struct us_listen_socket *) External::Cast(*args[0])->Value());
@@ -85,27 +47,15 @@ void Main(Local<Object> exports) {
     /* I guess we store this statically */
     isolate = exports->GetIsolate();
 
-    /* We want this */
+    /* We want this so that we can redefine process.nextTick to using the V8 native microtask queue */
     isolate->SetMicrotasksPolicy(MicrotasksPolicy::kAuto);
 
-    /* Register our own nextTick handlers */
-    uWS::Loop::defaultLoop()->setPostHandler([](uWS::Loop *) {
-        processNextTickQueueImpl(isolate);
-    });
-
-    /* We also do need it on pre */
-    uWS::Loop::defaultLoop()->setPreHandler([](uWS::Loop *) {
-        processNextTickQueueImpl(isolate);
-    });
-
     /* Hook up our timers */
     us_loop_integrate((us_loop *) uWS::Loop::defaultLoop());
 
     /* uWS namespace */
     exports->Set(String::NewFromUtf8(isolate, "App"), FunctionTemplate::New(isolate, uWS_App<uWS::App>)->GetFunction());
     exports->Set(String::NewFromUtf8(isolate, "SSLApp"), FunctionTemplate::New(isolate, uWS_App<uWS::SSLApp>)->GetFunction());
-    exports->Set(String::NewFromUtf8(isolate, "nextTick"), FunctionTemplate::New(isolate, nextTick)->GetFunction());
-    exports->Set(String::NewFromUtf8(isolate, "processNextTickQueue"), FunctionTemplate::New(isolate, processNextTickQueue)->GetFunction());
     exports->Set(String::NewFromUtf8(isolate, "print"), FunctionTemplate::New(isolate, print)->GetFunction());
 
     /* Expose some µSockets functions directly under uWS namespace */
diff --git a/src/uws.js b/src/uws.js
index 2f418a7..2ad88fa 100644
--- a/src/uws.js
+++ b/src/uws.js
@@ -20,18 +20,10 @@ module.exports = (() => {
 		const uWS = require(`./uws_${process.platform}_${process.versions.modules}.node`);
 		/* We are not compatible with Node.js nextTick and/or domains */
 		process.nextTick = (f, ...args) => {
-			uWS.nextTick(() => {
+			Promise.resolve().then(() => {
 				f(...args);
 			});
 		};
-		process.on('beforeExit', () => {
-			if (uWS.processNextTickQueue()) {
-				setImmediate(() => {
-
-				});
-			}
-		});
-		/* process.nextTick = setImmediate; */
 		return uWS;
 	} catch (e) {
 		throw new Error('This version of µWS is not compatible with your Node.js build.\n\n' + e.toString());