domain: re-implement domain over async_hook

lib/domain.js

@@ -28,7 +28,7 @@
 
 const util = require('util');
 const EventEmitter = require('events');
-const { inherits } = util;
+const { createHook } = require('async_hooks');
 
 // communicate with events module, but don't require that
 // module to have to load this one, since this module has
@@ -48,13 +48,54 @@ Object.defineProperty(process, 'domain', {
   }
 });
 
+const pairing = new Map();
+const asyncHook = createHook({
+  init(asyncId, type, triggerAsyncId, resource) {
+    if (process.domain !== null && process.domain !== undefined) {
+      // if this operation is created while in a domain, let's mark it
+      pairing.set(asyncId, process.domain);
+      resource.domain = process.domain;
+      if (resource.promise !== undefined &&
+          resource.promise instanceof Promise) {
+        // resource.promise instanceof Promise make sure that the
+        // promise comes from the same context
+        // see https://github.com/nodejs/node/issues/15673
+        resource.promise.domain = process.domain;
+      }
+    }
+  },
+  before(asyncId) {
+    const current = pairing.get(asyncId);
+    if (current !== undefined) { // enter domain for this cb
+      current.enter();
+    }
+  },
+  after(asyncId) {
+    const current = pairing.get(asyncId);
+    if (current !== undefined) { // exit domain for this cb
+      current.exit();
+    }
+  },
+  destroy(asyncId) {
+    pairing.delete(asyncId); // cleaning up
+  }
+});
+
 // It's possible to enter one domain while already inside
 // another one. The stack is each entered domain.
 const stack = [];
 exports._stack = stack;
+process._setupDomainUse(stack);
+
+class Domain extends EventEmitter {
 
-// let the process know we're using domains
-const _domain_flag = process._setupDomainUse(_domain, stack);
+  constructor() {
+    super();
+
+    this.members = [];
+    asyncHook.enable();
+  }
+}
 
 exports.Domain = Domain;
 
@@ -64,19 +105,8 @@ exports.create = exports.createDomain = function() {
 
 // the active domain is always the one that we're currently in.
 exports.active = null;
-
-
-inherits(Domain, EventEmitter);
-
-function Domain() {
-  EventEmitter.call(this);
-
-  this.members = [];
-}
-
 Domain.prototype.members = undefined;
 
-
 // Called by process._fatalException in case an error was thrown.
 Domain.prototype._errorHandler = function _errorHandler(er) {
   var caught = false;
@@ -155,7 +185,6 @@ Domain.prototype.enter = function() {
   // to push it onto the stack so that we can pop it later.
   exports.active = process.domain = this;
   stack.push(this);
-  _domain_flag[0] = stack.length;
 };
 
 
@@ -166,7 +195,6 @@ Domain.prototype.exit = function() {
 
   // exit all domains until this one.
   stack.splice(index);
-  _domain_flag[0] = stack.length;
 
   exports.active = stack[stack.length - 1];
   process.domain = exports.active;

lib/internal/process/next_tick.js

@@ -73,7 +73,6 @@ function setupNextTick() {
   process.nextTick = nextTick;
   // Needs to be accessible from beyond this scope.
   process._tickCallback = _tickCallback;
-  process._tickDomainCallback = _tickDomainCallback;
 
   // Set the nextTick() function for internal usage.
   exports.nextTick = internalNextTick;
@@ -190,46 +189,6 @@ function setupNextTick() {
     } while (tickInfo[kLength] !== 0);
   }
 
-  function _tickDomainCallback() {
-    do {
-      while (tickInfo[kIndex] < tickInfo[kLength]) {
-        ++tickInfo[kIndex];
-        const tock = nextTickQueue.shift();
-        const callback = tock.callback;
-        const domain = tock.domain;
-        const args = tock.args;
-        if (domain)
-          domain.enter();
-
-        // CHECK(Number.isSafeInteger(tock[async_id_symbol]))
-        // CHECK(tock[async_id_symbol] > 0)
-        // CHECK(Number.isSafeInteger(tock[trigger_async_id_symbol]))
-        // CHECK(tock[trigger_async_id_symbol] > 0)
-
-        emitBefore(tock[async_id_symbol], tock[trigger_async_id_symbol]);
-        // TODO(trevnorris): See comment in _tickCallback() as to why this
-        // isn't a good solution.
-        if (async_hook_fields[kDestroy] > 0)
-          emitDestroy(tock[async_id_symbol]);
-
-        // Using separate callback execution functions allows direct
-        // callback invocation with small numbers of arguments to avoid the
-        // performance hit associated with using `fn.apply()`
-        _combinedTickCallback(args, callback);
-
-        emitAfter(tock[async_id_symbol]);
-
-        if (kMaxCallbacksPerLoop < tickInfo[kIndex])
-          tickDone();
-        if (domain)
-          domain.exit();
-      }
-      tickDone();
-      _runMicrotasks();
-      emitPendingUnhandledRejections();
-    } while (tickInfo[kLength] !== 0);
-  }
-
   class TickObject {
     constructor(callback, args, asyncId, triggerAsyncId) {
       this.callback = callback;

src/cares_wrap.cc

@@ -596,12 +596,6 @@ class QueryWrap : public AsyncWrap {
   QueryWrap(ChannelWrap* channel, Local<Object> req_wrap_obj)
       : AsyncWrap(channel->env(), req_wrap_obj, AsyncWrap::PROVIDER_QUERYWRAP),
         channel_(channel) {
-    if (env()->in_domain()) {
-      req_wrap_obj->Set(env()->domain_string(),
-                        env()->domain_array()->Get(env()->context(), 0)
-                            .ToLocalChecked());
-    }
-
     Wrap(req_wrap_obj, this);
 
     // Make sure the channel object stays alive during the query lifetime.

src/env-inl.h

@@ -200,22 +200,6 @@ inline bool Environment::AsyncCallbackScope::in_makecallback() const {
   return env_->makecallback_cntr_ > 1;
 }
 
-inline Environment::DomainFlag::DomainFlag() {
-  for (int i = 0; i < kFieldsCount; ++i) fields_[i] = 0;
-}
-
-inline uint32_t* Environment::DomainFlag::fields() {
-  return fields_;
-}
-
-inline int Environment::DomainFlag::fields_count() const {
-  return kFieldsCount;
-}
-
-inline uint32_t Environment::DomainFlag::count() const {
-  return fields_[kCount];
-}
-
 inline Environment::TickInfo::TickInfo() {
   for (int i = 0; i < kFieldsCount; ++i)
     fields_[i] = 0;
@@ -349,12 +333,6 @@ inline v8::Isolate* Environment::isolate() const {
   return isolate_;
 }
 
-inline bool Environment::in_domain() const {
-  // The const_cast is okay, it doesn't violate conceptual const-ness.
-  return using_domains() &&
-         const_cast<Environment*>(this)->domain_flag()->count() > 0;
-}
-
 inline Environment* Environment::from_immediate_check_handle(
     uv_check_t* handle) {
   return ContainerOf(&Environment::immediate_check_handle_, handle);
@@ -395,10 +373,6 @@ inline Environment::AsyncHooks* Environment::async_hooks() {
   return &async_hooks_;
 }
 
-inline Environment::DomainFlag* Environment::domain_flag() {
-  return &domain_flag_;
-}
-
 inline Environment::TickInfo* Environment::tick_info() {
   return &tick_info_;
 }

src/env.h

@@ -309,7 +309,6 @@ class ModuleWrap;
   V(internal_binding_cache_object, v8::Object)                                \
   V(buffer_prototype_object, v8::Object)                                      \
   V(context, v8::Context)                                                     \
-  V(domain_array, v8::Array)                                                  \
   V(domains_stack_array, v8::Array)                                           \
   V(inspector_console_api_object, v8::Object)                                 \
   V(module_load_list_array, v8::Array)                                        \
@@ -472,26 +471,6 @@ class Environment {
     DISALLOW_COPY_AND_ASSIGN(AsyncCallbackScope);
   };
 
-  class DomainFlag {
-   public:
-    inline uint32_t* fields();
-    inline int fields_count() const;
-    inline uint32_t count() const;
-
-   private:
-    friend class Environment;  // So we can call the constructor.
-    inline DomainFlag();
-
-    enum Fields {
-      kCount,
-      kFieldsCount
-    };
-
-    uint32_t fields_[kFieldsCount];
-
-    DISALLOW_COPY_AND_ASSIGN(DomainFlag);
-  };
-
   class TickInfo {
    public:
     inline uint32_t* fields();
@@ -560,7 +539,6 @@ class Environment {
 
   inline v8::Isolate* isolate() const;
   inline uv_loop_t* event_loop() const;
-  inline bool in_domain() const;
   inline uint32_t watched_providers() const;
 
   static inline Environment* from_immediate_check_handle(uv_check_t* handle);
@@ -577,7 +555,6 @@ class Environment {
   inline void FinishHandleCleanup(uv_handle_t* handle);
 
   inline AsyncHooks* async_hooks();
-  inline DomainFlag* domain_flag();
   inline TickInfo* tick_info();
   inline uint64_t timer_base() const;
 
@@ -722,7 +699,6 @@ class Environment {
   uv_check_t idle_check_handle_;
 
   AsyncHooks async_hooks_;
-  DomainFlag domain_flag_;
   TickInfo tick_info_;
   const uint64_t timer_base_;
   bool using_domains_;

src/node.cc

@@ -160,7 +160,6 @@ using v8::Number;
 using v8::Object;
 using v8::ObjectTemplate;
 using v8::Promise;
-using v8::PromiseHookType;
 using v8::PromiseRejectMessage;
 using v8::PropertyCallbackInfo;
 using v8::ScriptOrigin;
@@ -842,7 +841,6 @@ bool ShouldAbortOnUncaughtException(Isolate* isolate) {
   return isEmittingTopLevelDomainError || !DomainsStackHasErrorHandler(env);
 }
 
-
 Local<Value> GetDomainProperty(Environment* env, Local<Object> object) {
   Local<Value> domain_v =
       object->GetPrivate(env->context(), env->domain_private_symbol())
@@ -883,36 +881,6 @@ void DomainExit(Environment* env, v8::Local<v8::Object> object) {
   }
 }
 
-
-void DomainPromiseHook(PromiseHookType type,
-                       Local<Promise> promise,
-                       Local<Value> parent,
-                       void* arg) {
-  Environment* env = static_cast<Environment*>(arg);
-  Local<Context> context = env->context();
-
-  if (type == PromiseHookType::kInit && env->in_domain()) {
-    Local<Value> domain_obj =
-        env->domain_array()->Get(context, 0).ToLocalChecked();
-    if (promise->CreationContext() == context) {
-      promise->Set(context, env->domain_string(), domain_obj).FromJust();
-    } else {
-      // Do not expose object from another context publicly in promises created
-      // in non-main contexts.
-      promise->SetPrivate(context, env->domain_private_symbol(), domain_obj)
-          .FromJust();
-    }
-    return;
-  }
-
-  if (type == PromiseHookType::kBefore) {
-    DomainEnter(env, promise);
-  } else if (type == PromiseHookType::kAfter) {
-    DomainExit(env, promise);
-  }
-}
-
-
 void SetupDomainUse(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
@@ -923,38 +891,13 @@ void SetupDomainUse(const FunctionCallbackInfo<Value>& args) {
   HandleScope scope(env->isolate());
   Local<Object> process_object = env->process_object();
 
-  Local<String> tick_callback_function_key = env->tick_domain_cb_string();
-  Local<Function> tick_callback_function =
-      process_object->Get(tick_callback_function_key).As<Function>();
-
-  if (!tick_callback_function->IsFunction()) {
-    fprintf(stderr, "process._tickDomainCallback assigned to non-function\n");
-    ABORT();
-  }
-
-  process_object->Set(env->tick_callback_string(), tick_callback_function);
-  env->set_tick_callback_function(tick_callback_function);
-
   CHECK(args[0]->IsArray());
-  env->set_domain_array(args[0].As<Array>());
-
-  CHECK(args[1]->IsArray());
-  env->set_domains_stack_array(args[1].As<Array>());
+  env->set_domains_stack_array(args[0].As<Array>());
 
   // Do a little housekeeping.
   env->process_object()->Delete(
       env->context(),
       FIXED_ONE_BYTE_STRING(args.GetIsolate(), "_setupDomainUse")).FromJust();
-
-  uint32_t* const fields = env->domain_flag()->fields();
-  uint32_t const fields_count = env->domain_flag()->fields_count();
-
-  Local<ArrayBuffer> array_buffer =
-      ArrayBuffer::New(env->isolate(), fields, sizeof(*fields) * fields_count);
-
-  env->AddPromiseHook(DomainPromiseHook, static_cast<void*>(env));
-
-  args.GetReturnValue().Set(Uint32Array::New(array_buffer, 0, fields_count));
 }
 
 
@@ -1078,7 +1021,8 @@ InternalCallbackScope::InternalCallbackScope(Environment* env,
   // If you hit this assertion, you forgot to enter the v8::Context first.
   CHECK_EQ(Environment::GetCurrent(env->isolate()), env);
 
-  if (env->using_domains() && !object_.IsEmpty()) {
+  if (asyncContext.async_id == 0 && env->using_domains() &&
+      !object_.IsEmpty()) {
     DomainEnter(env, object_);
   }
 
@@ -1111,7 +1055,8 @@ void InternalCallbackScope::Close() {
     AsyncWrap::EmitAfter(env_, async_context_.async_id);
   }
 
-  if (env_->using_domains() && !object_.IsEmpty()) {
+  if (async_context_.async_id == 0 && env_->using_domains() &&
+      !object_.IsEmpty()) {
     DomainExit(env_, object_);
   }