async_wrap,src: promise hook integration

lib/async_hooks.js

@@ -49,12 +49,7 @@ const before_symbol = Symbol('before');
 const after_symbol = Symbol('after');
 const destroy_symbol = Symbol('destroy');
 
-// Setup the callbacks that node::AsyncWrap will call when there are hooks to
-// process. They use the same functions as the JS embedder API.
-async_wrap.setupHooks({ init,
-                        before: emitBeforeN,
-                        after: emitAfterN,
-                        destroy: emitDestroyN });
+let setupHooksCalled = false;
 
 // Used to fatally abort the process if a callback throws.
 function fatalError(e) {
@@ -103,6 +98,16 @@ class AsyncHook {
     if (hooks_array.includes(this))
       return;
 
+    if (!setupHooksCalled) {
+      setupHooksCalled = true;
+      // Setup the callbacks that node::AsyncWrap will call when there are
+      // hooks to process. They use the same functions as the JS embedder API.
+      async_wrap.setupHooks({ init,
+                              before: emitBeforeN,
+                              after: emitAfterN,
+                              destroy: emitDestroyN });
+    }
+
     // createHook() has already enforced that the callbacks are all functions,
     // so here simply increment the count of whether each callbacks exists or
     // not.

src/async-wrap.cc

@@ -44,6 +44,8 @@ using v8::Local;
 using v8::MaybeLocal;
 using v8::Number;
 using v8::Object;
+using v8::Promise;
+using v8::PromiseHookType;
 using v8::RetainedObjectInfo;
 using v8::Symbol;
 using v8::TryCatch;
@@ -177,6 +179,143 @@ static void PushBackDestroyId(Environment* env, double id) {
 }
 
 
+bool DomainEnter(Environment* env, Local<Object> object) {
+  Local<Value> domain_v = object->Get(env->domain_string());
+  if (domain_v->IsObject()) {
+    Local<Object> domain = domain_v.As<Object>();
+    if (domain->Get(env->disposed_string())->IsTrue())
+      return true;
+    Local<Value> enter_v = domain->Get(env->enter_string());
+    if (enter_v->IsFunction()) {
+      if (enter_v.As<Function>()->Call(domain, 0, nullptr).IsEmpty()) {
+        FatalError("node::AsyncWrap::MakeCallback",
+                   "domain enter callback threw, please report this");
+      }
+    }
+  }
+  return false;
+}
+
+
+bool DomainExit(Environment* env, v8::Local<v8::Object> object) {
+  Local<Value> domain_v = object->Get(env->domain_string());
+  if (domain_v->IsObject()) {
+    Local<Object> domain = domain_v.As<Object>();
+    if (domain->Get(env->disposed_string())->IsTrue())
+      return true;
+    Local<Value> exit_v = domain->Get(env->exit_string());
+    if (exit_v->IsFunction()) {
+      if (exit_v.As<Function>()->Call(domain, 0, nullptr).IsEmpty()) {
+        FatalError("node::AsyncWrap::MakeCallback",
+                  "domain exit callback threw, please report this");
+      }
+    }
+  }
+  return false;
+}
+
+
+static bool PreCallbackExecution(AsyncWrap* wrap, bool run_domain_cbs) {
+  AsyncHooks* async_hooks = wrap->env()->async_hooks();
+
+  if (wrap->env()->using_domains() && run_domain_cbs) {
+    bool is_disposed = DomainEnter(wrap->env(), wrap->object());
+    if (is_disposed)
+      return false;
+  }
+
+  if (async_hooks->fields()[AsyncHooks::kBefore] > 0) {
+    Local<Value> uid = Number::New(wrap->env()->isolate(), wrap->get_id());
+    Local<Function> fn = wrap->env()->async_hooks_before_function();
+    TryCatch try_catch(wrap->env()->isolate());
+    MaybeLocal<Value> ar = fn->Call(
+        wrap->env()->context(), Undefined(wrap->env()->isolate()), 1, &uid);
+    if (ar.IsEmpty()) {
+      ClearFatalExceptionHandlers(wrap->env());
+      FatalException(wrap->env()->isolate(), try_catch);
+      return false;
+    }
+  }
+
+  return true;
+}
+
+
+static bool PostCallbackExecution(AsyncWrap* wrap, bool run_domain_cbs) {
+  AsyncHooks* async_hooks = wrap->env()->async_hooks();
+
+  // If the callback failed then the after() hooks will be called at the end
+  // of _fatalException().
+  if (async_hooks->fields()[AsyncHooks::kAfter] > 0) {
+    Local<Value> uid = Number::New(wrap->env()->isolate(), wrap->get_id());
+    Local<Function> fn = wrap->env()->async_hooks_after_function();
+    TryCatch try_catch(wrap->env()->isolate());
+    MaybeLocal<Value> ar = fn->Call(
+        wrap->env()->context(), Undefined(wrap->env()->isolate()), 1, &uid);
+    if (ar.IsEmpty()) {
+      ClearFatalExceptionHandlers(wrap->env());
+      FatalException(wrap->env()->isolate(), try_catch);
+      return false;
+    }
+  }
+
+  if (wrap->env()->using_domains() && run_domain_cbs) {
+    bool is_disposed = DomainExit(wrap->env(), wrap->object());
+    if (is_disposed)
+      return false;
+  }
+
+  return true;
+}
+
+class PromiseWrap : public AsyncWrap {
+ public:
+  PromiseWrap(Environment* env, Local<Object> object)
+    : AsyncWrap(env, object, PROVIDER_PROMISE) {}
+  size_t self_size() const override { return sizeof(*this); }
+};
+
+
+static void PromiseHook(PromiseHookType type, Local<Promise> promise,
+                        Local<Value> parent, void* arg) {
+  Local<Context> context = promise->CreationContext();
+  Environment* env = Environment::GetCurrent(context);
+  if (type == PromiseHookType::kInit) {
+    // Unfortunately, promises don't have internal fields. Need a surrogate that
+    // async wrap can wrap.
+    Local<Object> obj =
+      env->async_hooks_promise_object()->NewInstance(context).ToLocalChecked();
+    PromiseWrap* wrap = new PromiseWrap(env, obj);
+    v8::PropertyAttribute hidden =
+      static_cast<v8::PropertyAttribute>(v8::ReadOnly
+                                         | v8::DontDelete
+                                         | v8::DontEnum);
+    promise->DefineOwnProperty(context,
+              env->promise_wrap(),
+              v8::External::New(env->isolate(), wrap),
+              hidden).FromJust();
+    // The async tag will be destroyed at the same time as the promise as the
+    // only reference to it is held by the promise. This allows the promise
+    // wrap instance to be notified when the promise is destroyed.
+    promise->DefineOwnProperty(context,
+              env->promise_async_tag(),
+              obj, hidden).FromJust();
+  } else if (type == PromiseHookType::kResolve) {
+    // TODO(matthewloring): need to expose this through the async hooks api.
+  }
+  Local<v8::Value> external_wrap =
+      promise->Get(context, env->promise_wrap()).ToLocalChecked();
+  PromiseWrap* wrap =
+    static_cast<PromiseWrap*>(external_wrap.As<v8::External>()->Value());
+  CHECK_NE(wrap, nullptr);
+  if (type == PromiseHookType::kBefore) {
+    PreCallbackExecution(wrap, false);
+  } else if (type == PromiseHookType::kAfter) {
+    PostCallbackExecution(wrap, false);
+  }
+}
+
+
 static void SetupHooks(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
@@ -201,6 +340,7 @@ static void SetupHooks(const FunctionCallbackInfo<Value>& args) {
   SET_HOOK_FN(before);
   SET_HOOK_FN(after);
   SET_HOOK_FN(destroy);
+  env->AddPromiseHook(PromiseHook, nullptr);
 #undef SET_HOOK_FN
 }
 
@@ -262,6 +402,11 @@ void AsyncWrap::Initialize(Local<Object> target,
   env->SetMethod(target, "clearIdStack", ClearIdStack);
   env->SetMethod(target, "addIdToDestroyList", QueueDestroyId);
 
+  Local<v8::ObjectTemplate> promise_object_template =
+    v8::ObjectTemplate::New(env->isolate());
+  promise_object_template->SetInternalFieldCount(1);
+  env->set_async_hooks_promise_object(promise_object_template);
+
   v8::PropertyAttribute ReadOnlyDontDelete =
       static_cast<v8::PropertyAttribute>(v8::ReadOnly | v8::DontDelete);
 
@@ -416,87 +561,30 @@ Local<Value> AsyncWrap::MakeCallback(const Local<Function> cb,
                                      Local<Value>* argv) {
   CHECK(env()->context() == env()->isolate()->GetCurrentContext());
 
-  AsyncHooks* async_hooks = env()->async_hooks();
-  Local<Object> context = object();
-  Local<Object> domain;
-  Local<Value> uid;
-  bool has_domain = false;
-
   Environment::AsyncCallbackScope callback_scope(env());
 
-  if (env()->using_domains()) {
-    Local<Value> domain_v = context->Get(env()->domain_string());
-    has_domain = domain_v->IsObject();
-    if (has_domain) {
-      domain = domain_v.As<Object>();
-      if (domain->Get(env()->disposed_string())->IsTrue())
-        return Local<Value>();
-    }
-  }
+  Environment::AsyncHooks::ExecScope exec_scope(env(),
+                                                get_id(),
+                                                get_trigger_id());
 
-  if (has_domain) {
-    Local<Value> enter_v = domain->Get(env()->enter_string());
-    if (enter_v->IsFunction()) {
-      if (enter_v.As<Function>()->Call(domain, 0, nullptr).IsEmpty()) {
-        FatalError("node::AsyncWrap::MakeCallback",
-                   "domain enter callback threw, please report this");
-      }
-    }
-  }
-
-  // Want currentId() to return the correct value from the callbacks.
-  AsyncHooks::ExecScope exec_scope(env(), get_id(), get_trigger_id());
-
-  if (async_hooks->fields()[AsyncHooks::kBefore] > 0) {
-    uid = Number::New(env()->isolate(), get_id());
-    Local<Function> fn = env()->async_hooks_before_function();
-    TryCatch try_catch(env()->isolate());
-    MaybeLocal<Value> ar = fn->Call(
-        env()->context(), Undefined(env()->isolate()), 1, &uid);
-    if (ar.IsEmpty()) {
-      ClearFatalExceptionHandlers(env());
-      FatalException(env()->isolate(), try_catch);
-      return Local<Value>();
-    }
+  if (!PreCallbackExecution(this, true)) {
+    return Local<Value>();
   }
 
   // Finally... Get to running the user's callback.
-  MaybeLocal<Value> ret = cb->Call(env()->context(), context, argc, argv);
+  MaybeLocal<Value> ret = cb->Call(env()->context(), object(), argc, argv);
 
   Local<Value> ret_v;
   if (!ret.ToLocal(&ret_v)) {
     return Local<Value>();
   }
 
-  // If the callback failed then the after() hooks will be called at the end
-  // of _fatalException().
-  if (async_hooks->fields()[AsyncHooks::kAfter] > 0) {
-    if (uid.IsEmpty())
-      uid = Number::New(env()->isolate(), get_id());
-    Local<Function> fn = env()->async_hooks_after_function();
-    TryCatch try_catch(env()->isolate());
-    MaybeLocal<Value> ar = fn->Call(
-        env()->context(), Undefined(env()->isolate()), 1, &uid);
-    if (ar.IsEmpty()) {
-      ClearFatalExceptionHandlers(env());
-      FatalException(env()->isolate(), try_catch);
-      return Local<Value>();
-    }
+  if (!PostCallbackExecution(this, true)) {
+    return Local<Value>();
   }
 
-  // The execution scope of the id and trigger_id only go this far.
   exec_scope.Dispose();
 
-  if (has_domain) {
-    Local<Value> exit_v = domain->Get(env()->exit_string());
-    if (exit_v->IsFunction()) {
-      if (exit_v.As<Function>()->Call(domain, 0, nullptr).IsEmpty()) {
-        FatalError("node::AsyncWrap::MakeCallback",
-                   "domain exit callback threw, please report this");
-      }
-    }
-  }
-
   if (callback_scope.in_makecallback()) {
     return ret_v;
   }

src/async-wrap.h

@@ -47,6 +47,7 @@ namespace node {
   V(PIPECONNECTWRAP)                                                          \
   V(PIPEWRAP)                                                                 \
   V(PROCESSWRAP)                                                              \
+  V(PROMISE)                                                                  \
   V(QUERYWRAP)                                                                \
   V(RANDOMBYTESREQUEST)                                                       \
   V(SHUTDOWNWRAP)                                                             \
@@ -123,6 +124,9 @@ class AsyncWrap : public BaseObject {
 
 void LoadAsyncWrapperInfo(Environment* env);
 
+bool DomainEnter(Environment* env, v8::Local<v8::Object> object);
+bool DomainExit(Environment* env, v8::Local<v8::Object> object);
+
 }  // namespace node
 
 #endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

src/env.h

@@ -195,6 +195,8 @@ namespace node {
   V(preference_string, "preference")                                          \
   V(priority_string, "priority")                                              \
   V(produce_cached_data_string, "produceCachedData")                          \
+  V(promise_wrap, "_promise_async_wrap")                                      \
+  V(promise_async_tag, "_promise_async_wrap_tag")                             \
   V(raw_string, "raw")                                                        \
   V(read_host_object_string, "_readHostObject")                               \
   V(readable_string, "readable")                                              \
@@ -256,6 +258,7 @@ namespace node {
   V(async_hooks_init_function, v8::Function)                                  \
   V(async_hooks_before_function, v8::Function)                                \
   V(async_hooks_after_function, v8::Function)                                 \
+  V(async_hooks_promise_object, v8::ObjectTemplate)                           \
   V(binding_cache_object, v8::Object)                                         \
   V(buffer_constructor_function, v8::Function)                                \
   V(buffer_prototype_object, v8::Object)                                      \

src/node.cc

@@ -1124,7 +1124,6 @@ void DomainPromiseHook(PromiseHookType type,
   Environment* env = static_cast<Environment*>(arg);
   Local<Context> context = env->context();
 
-  if (type == PromiseHookType::kResolve) return;
   if (type == PromiseHookType::kInit && env->in_domain()) {
     promise->Set(context,
                  env->domain_string(),
@@ -1133,38 +1132,10 @@ void DomainPromiseHook(PromiseHookType type,
     return;
   }
 
-  // Loosely based on node::MakeCallback().
-  Local<Value> domain_v =
-      promise->Get(context, env->domain_string()).ToLocalChecked();
-  if (!domain_v->IsObject())
-    return;
-
-  Local<Object> domain = domain_v.As<Object>();
-  if (domain->Get(context, env->disposed_string())
-          .ToLocalChecked()->IsTrue()) {
-    return;
-  }
-
   if (type == PromiseHookType::kBefore) {
-    Local<Value> enter_v =
-        domain->Get(context, env->enter_string()).ToLocalChecked();
-    if (enter_v->IsFunction()) {
-      if (enter_v.As<Function>()->Call(context, domain, 0, nullptr).IsEmpty()) {
-        FatalError("node::PromiseHook",
-                   "domain enter callback threw, please report this "
-                   "as a bug in Node.js");
-      }
-    }
-  } else {
-    Local<Value> exit_v =
-        domain->Get(context, env->exit_string()).ToLocalChecked();
-    if (exit_v->IsFunction()) {
-      if (exit_v.As<Function>()->Call(context, domain, 0, nullptr).IsEmpty()) {
-        FatalError("node::MakeCallback",
-                   "domain exit callback threw, please report this "
-                   "as a bug in Node.js");
-      }
-    }
+    DomainEnter(env, promise);
+  } else if (type == PromiseHookType::kAfter) {
+    DomainExit(env, promise);
   }
 }