async-wrap: explicitly pass parent

When instantiating a new AsyncWrap allow the parent AsyncWrap to be
passed. This is useful for cases like TCP incoming connections, so the
connection can be tied to the server receiving the connection.

Because the current architecture instantiates the *Wrap inside a
v8::FunctionCallback, the parent pointer is currently wrapped inside a
new v8::External every time and passed as an argument. This adds ~80ns
to instantiation time.

A future optimization would be to add the v8::External as the data field
when creating the v8::FunctionTemplate, change the pointer just before
making the call then NULL'ing it out afterwards. This adds enough code
complexity that it will not be attempted until the current approach
demonstrates it is a bottle neck.

PR-URL: https://github.com/joyent/node/pull/8110
Signed-off-by: Trevor Norris <trev.norris@gmail.com>
Reviewed-by: Fedor Indutny <fedor@indutny.com>
Reviewed-by: Alexis Campailla <alexis@janeasystems.com>
Reviewed-by: Julien Gilli <julien.gilli@joyent.com>

12 files changed, 89 insertions, 35 deletions

diff --git a/src/async-wrap-inl.h b/src/async-wrap-inl.h
index 7a298a1497b..73a177872e9 100644
--- a/src/async-wrap-inl.h
+++ b/src/async-wrap-inl.h
@@ -35,7 +35,8 @@ namespace node {
 
 inline AsyncWrap::AsyncWrap(Environment* env,
                             v8::Handle<v8::Object> object,
-                            ProviderType provider)
+                            ProviderType provider,
+                            AsyncWrap* parent)
     : BaseObject(env, object),
       provider_type_(provider) {
 }
diff --git a/src/async-wrap.h b/src/async-wrap.h
index 5a2c35ac941..ea8dfd3f012 100644
--- a/src/async-wrap.h
+++ b/src/async-wrap.h
@@ -63,7 +63,8 @@ class AsyncWrap : public BaseObject {
 
   inline AsyncWrap(Environment* env,
                    v8::Handle<v8::Object> object,
-                   ProviderType provider);
+                   ProviderType provider,
+                   AsyncWrap* parent = nullptr);
 
   inline virtual ~AsyncWrap() override = default;
 
diff --git a/src/handle_wrap.cc b/src/handle_wrap.cc
index f4e34effc66..b42fa004460 100644
--- a/src/handle_wrap.cc
+++ b/src/handle_wrap.cc
@@ -83,8 +83,9 @@ void HandleWrap::Close(const FunctionCallbackInfo<Value>& args) {
 HandleWrap::HandleWrap(Environment* env,
                        Handle<Object> object,
                        uv_handle_t* handle,
-                       AsyncWrap::ProviderType provider)
-    : AsyncWrap(env, object, provider),
+                       AsyncWrap::ProviderType provider,
+                       AsyncWrap* parent)
+    : AsyncWrap(env, object, provider, parent),
       flags_(0),
       handle__(handle) {
   handle__->data = this;
diff --git a/src/handle_wrap.h b/src/handle_wrap.h
index 13457e7cc53..8c5898e134a 100644
--- a/src/handle_wrap.h
+++ b/src/handle_wrap.h
@@ -67,7 +67,8 @@ class HandleWrap : public AsyncWrap {
   HandleWrap(Environment* env,
              v8::Handle<v8::Object> object,
              uv_handle_t* handle,
-             AsyncWrap::ProviderType provider);
+             AsyncWrap::ProviderType provider,
+             AsyncWrap* parent = nullptr);
   virtual ~HandleWrap() override;
 
  private:
diff --git a/src/pipe_wrap.cc b/src/pipe_wrap.cc
index 512b438218e..b91ebe0e5ed 100644
--- a/src/pipe_wrap.cc
+++ b/src/pipe_wrap.cc
@@ -21,6 +21,7 @@
 
 #include "pipe_wrap.h"
 
+#include "async-wrap.h"
 #include "env.h"
 #include "env-inl.h"
 #include "handle_wrap.h"
@@ -37,6 +38,7 @@ namespace node {
 using v8::Boolean;
 using v8::Context;
 using v8::EscapableHandleScope;
+using v8::External;
 using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::FunctionTemplate;
@@ -74,12 +76,13 @@ uv_pipe_t* PipeWrap::UVHandle() {
 }
 
 
-Local<Object> PipeWrap::Instantiate(Environment* env) {
+Local<Object> PipeWrap::Instantiate(Environment* env, AsyncWrap* parent) {
   EscapableHandleScope handle_scope(env->isolate());
   CHECK_EQ(false, env->pipe_constructor_template().IsEmpty());
   Local<Function> constructor = env->pipe_constructor_template()->GetFunction();
   CHECK_EQ(false, constructor.IsEmpty());
-  Local<Object> instance = constructor->NewInstance();
+  Local<Value> ptr = External::New(env->isolate(), parent);
+  Local<Object> instance = constructor->NewInstance(1, &ptr);
   CHECK_EQ(false, instance.IsEmpty());
   return handle_scope.Escape(instance);
 }
@@ -147,15 +150,24 @@ void PipeWrap::New(const FunctionCallbackInfo<Value>& args) {
   // normal function.
   CHECK(args.IsConstructCall());
   Environment* env = Environment::GetCurrent(args);
-  new PipeWrap(env, args.This(), args[0]->IsTrue());
+  if (args[0]->IsExternal()) {
+    void* ptr = args[0].As<External>()->Value();
+    new PipeWrap(env, args.This(), false, static_cast<AsyncWrap*>(ptr));
+  } else {
+    new PipeWrap(env, args.This(), args[0]->IsTrue(), nullptr);
+  }
 }
 
 
-PipeWrap::PipeWrap(Environment* env, Handle<Object> object, bool ipc)
+PipeWrap::PipeWrap(Environment* env,
+                   Handle<Object> object,
+                   bool ipc,
+                   AsyncWrap* parent)
     : StreamWrap(env,
                  object,
                  reinterpret_cast<uv_stream_t*>(&handle_),
-                 AsyncWrap::PROVIDER_PIPEWRAP) {
+                 AsyncWrap::PROVIDER_PIPEWRAP,
+                 parent) {
   int r = uv_pipe_init(env->event_loop(), &handle_, ipc);
   CHECK_EQ(r, 0);  // How do we proxy this error up to javascript?
                    // Suggestion: uv_pipe_init() returns void.
@@ -214,7 +226,7 @@ void PipeWrap::OnConnection(uv_stream_t* handle, int status) {
   }
 
   // Instanciate the client javascript object and handle.
-  Local<Object> client_obj = Instantiate(env);
+  Local<Object> client_obj = Instantiate(env, pipe_wrap);
 
   // Unwrap the client javascript object.
   PipeWrap* wrap = Unwrap<PipeWrap>(client_obj);
diff --git a/src/pipe_wrap.h b/src/pipe_wrap.h
index 92492c42b73..959f28f4dca 100644
--- a/src/pipe_wrap.h
+++ b/src/pipe_wrap.h
@@ -22,6 +22,7 @@
 #ifndef SRC_PIPE_WRAP_H_
 #define SRC_PIPE_WRAP_H_
 
+#include "async-wrap.h"
 #include "env.h"
 #include "stream_wrap.h"
 
@@ -31,13 +32,16 @@ class PipeWrap : public StreamWrap {
  public:
   uv_pipe_t* UVHandle();
 
-  static v8::Local<v8::Object> Instantiate(Environment* env);
+  static v8::Local<v8::Object> Instantiate(Environment* env, AsyncWrap* parent);
   static void Initialize(v8::Handle<v8::Object> target,
                          v8::Handle<v8::Value> unused,
                          v8::Handle<v8::Context> context);
 
  private:
-  PipeWrap(Environment* env, v8::Handle<v8::Object> object, bool ipc);
+  PipeWrap(Environment* env,
+           v8::Handle<v8::Object> object,
+           bool ipc,
+           AsyncWrap* parent);
 
   static void New(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void Bind(const v8::FunctionCallbackInfo<v8::Value>& args);
diff --git a/src/stream_wrap.cc b/src/stream_wrap.cc
index 9d56793b1de..2d13ae0f888 100644
--- a/src/stream_wrap.cc
+++ b/src/stream_wrap.cc
@@ -81,8 +81,13 @@ void StreamWrap::Initialize(Handle<Object> target,
 StreamWrap::StreamWrap(Environment* env,
                        Local<Object> object,
                        uv_stream_t* stream,
-                       AsyncWrap::ProviderType provider)
-    : HandleWrap(env, object, reinterpret_cast<uv_handle_t*>(stream), provider),
+                       AsyncWrap::ProviderType provider,
+                       AsyncWrap* parent)
+    : HandleWrap(env,
+                 object,
+                 reinterpret_cast<uv_handle_t*>(stream),
+                 provider,
+                 parent),
       stream_(stream),
       default_callbacks_(this),
       callbacks_(&default_callbacks_),
@@ -140,12 +145,14 @@ void StreamWrap::OnAlloc(uv_handle_t* handle,
 
 
 template <class WrapType, class UVType>
-static Local<Object> AcceptHandle(Environment* env, uv_stream_t* pipe) {
+static Local<Object> AcceptHandle(Environment* env,
+                                  uv_stream_t* pipe,
+                                  AsyncWrap* parent) {
   EscapableHandleScope scope(env->isolate());
   Local<Object> wrap_obj;
   UVType* handle;
 
-  wrap_obj = WrapType::Instantiate(env);
+  wrap_obj = WrapType::Instantiate(env, parent);
   if (wrap_obj.IsEmpty())
     return Local<Object>();
 
@@ -751,11 +758,11 @@ void StreamWrapCallbacks::DoRead(uv_stream_t* handle,
 
   Local<Object> pending_obj;
   if (pending == UV_TCP) {
-    pending_obj = AcceptHandle<TCPWrap, uv_tcp_t>(env, handle);
+    pending_obj = AcceptHandle<TCPWrap, uv_tcp_t>(env, handle, wrap());
   } else if (pending == UV_NAMED_PIPE) {
-    pending_obj = AcceptHandle<PipeWrap, uv_pipe_t>(env, handle);
+    pending_obj = AcceptHandle<PipeWrap, uv_pipe_t>(env, handle, wrap());
   } else if (pending == UV_UDP) {
-    pending_obj = AcceptHandle<UDPWrap, uv_udp_t>(env, handle);
+    pending_obj = AcceptHandle<UDPWrap, uv_udp_t>(env, handle, wrap());
   } else {
     CHECK_EQ(pending, UV_UNKNOWN_HANDLE);
   }
diff --git a/src/stream_wrap.h b/src/stream_wrap.h
index 93c9f046e01..ded78eeecb2 100644
--- a/src/stream_wrap.h
+++ b/src/stream_wrap.h
@@ -177,7 +177,8 @@ class StreamWrap : public HandleWrap {
   StreamWrap(Environment* env,
              v8::Local<v8::Object> object,
              uv_stream_t* stream,
-             AsyncWrap::ProviderType provider);
+             AsyncWrap::ProviderType provider,
+             AsyncWrap* parent = nullptr);
 
   ~StreamWrap() {
     if (!callbacks_gc_ && callbacks_ != &default_callbacks_) {
diff --git a/src/tcp_wrap.cc b/src/tcp_wrap.cc
index 9c1aeee6490..3b280990436 100644
--- a/src/tcp_wrap.cc
+++ b/src/tcp_wrap.cc
@@ -39,6 +39,7 @@ namespace node {
 using v8::Boolean;
 using v8::Context;
 using v8::EscapableHandleScope;
+using v8::External;
 using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::FunctionTemplate;
@@ -70,12 +71,13 @@ static void NewTCPConnectWrap(const FunctionCallbackInfo<Value>& args) {
 }
 
 
-Local<Object> TCPWrap::Instantiate(Environment* env) {
+Local<Object> TCPWrap::Instantiate(Environment* env, AsyncWrap* parent) {
   EscapableHandleScope handle_scope(env->isolate());
   CHECK_EQ(env->tcp_constructor_template().IsEmpty(), false);
   Local<Function> constructor = env->tcp_constructor_template()->GetFunction();
   CHECK_EQ(constructor.IsEmpty(), false);
-  Local<Object> instance = constructor->NewInstance();
+  Local<Value> ptr = External::New(env->isolate(), parent);
+  Local<Object> instance = constructor->NewInstance(1, &ptr);
   CHECK_EQ(instance.IsEmpty(), false);
   return handle_scope.Escape(instance);
 }
@@ -166,16 +168,25 @@ void TCPWrap::New(const FunctionCallbackInfo<Value>& args) {
   // normal function.
   CHECK(args.IsConstructCall());
   Environment* env = Environment::GetCurrent(args);
-  TCPWrap* wrap = new TCPWrap(env, args.This());
+  TCPWrap* wrap;
+  if (args.Length() == 0) {
+    wrap = new TCPWrap(env, args.This(), nullptr);
+  } else if (args[0]->IsExternal()) {
+    void* ptr = args[0].As<External>()->Value();
+    wrap = new TCPWrap(env, args.This(), static_cast<AsyncWrap*>(ptr));
+  } else {
+    UNREACHABLE();
+  }
   CHECK(wrap);
 }
 
 
-TCPWrap::TCPWrap(Environment* env, Handle<Object> object)
+TCPWrap::TCPWrap(Environment* env, Handle<Object> object, AsyncWrap* parent)
     : StreamWrap(env,
                  object,
                  reinterpret_cast<uv_stream_t*>(&handle_),
-                 AsyncWrap::PROVIDER_TCPWRAP) {
+                 AsyncWrap::PROVIDER_TCPWRAP,
+                 parent) {
   int r = uv_tcp_init(env->event_loop(), &handle_);
   CHECK_EQ(r, 0);  // How do we proxy this error up to javascript?
                    // Suggestion: uv_tcp_init() returns void.
@@ -325,7 +336,8 @@ void TCPWrap::OnConnection(uv_stream_t* handle, int status) {
 
   if (status == 0) {
     // Instantiate the client javascript object and handle.
-    Local<Object> client_obj = Instantiate(env);
+    Local<Object> client_obj =
+        Instantiate(env, static_cast<AsyncWrap*>(tcp_wrap));
 
     // Unwrap the client javascript object.
     TCPWrap* wrap = Unwrap<TCPWrap>(client_obj);
diff --git a/src/tcp_wrap.h b/src/tcp_wrap.h
index c9981f572db..c923b387f0e 100644
--- a/src/tcp_wrap.h
+++ b/src/tcp_wrap.h
@@ -22,6 +22,7 @@
 #ifndef SRC_TCP_WRAP_H_
 #define SRC_TCP_WRAP_H_
 
+#include "async-wrap.h"
 #include "env.h"
 #include "stream_wrap.h"
 
@@ -29,7 +30,7 @@ namespace node {
 
 class TCPWrap : public StreamWrap {
  public:
-  static v8::Local<v8::Object> Instantiate(Environment* env);
+  static v8::Local<v8::Object> Instantiate(Environment* env, AsyncWrap* parent);
   static void Initialize(v8::Handle<v8::Object> target,
                          v8::Handle<v8::Value> unused,
                          v8::Handle<v8::Context> context);
@@ -37,7 +38,7 @@ class TCPWrap : public StreamWrap {
   uv_tcp_t* UVHandle();
 
  private:
-  TCPWrap(Environment* env, v8::Handle<v8::Object> object);
+  TCPWrap(Environment* env, v8::Handle<v8::Object> object, AsyncWrap* parent);
   ~TCPWrap();
 
   static void New(const v8::FunctionCallbackInfo<v8::Value>& args);
diff --git a/src/udp_wrap.cc b/src/udp_wrap.cc
index 42b5f1f03a3..e58503b40ac 100644
--- a/src/udp_wrap.cc
+++ b/src/udp_wrap.cc
@@ -34,6 +34,8 @@
 namespace node {
 
 using v8::Context;
+using v8::EscapableHandleScope;
+using v8::External;
 using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::FunctionTemplate;
@@ -78,7 +80,7 @@ static void NewSendWrap(const FunctionCallbackInfo<Value>& args) {
 }
 
 
-UDPWrap::UDPWrap(Environment* env, Handle<Object> object)
+UDPWrap::UDPWrap(Environment* env, Handle<Object> object, AsyncWrap* parent)
     : HandleWrap(env,
                  object,
                  reinterpret_cast<uv_handle_t*>(&handle_),
@@ -140,7 +142,15 @@ void UDPWrap::Initialize(Handle<Object> target,
 void UDPWrap::New(const FunctionCallbackInfo<Value>& args) {
   CHECK(args.IsConstructCall());
   Environment* env = Environment::GetCurrent(args);
-  new UDPWrap(env, args.This());
+  if (args.Length() == 0) {
+    new UDPWrap(env, args.This(), nullptr);
+  } else if (args[0]->IsExternal()) {
+    new UDPWrap(env,
+                args.This(),
+                static_cast<AsyncWrap*>(args[0].As<External>()->Value()));
+  } else {
+    UNREACHABLE();
+  }
 }
 
 
@@ -423,10 +433,12 @@ void UDPWrap::OnRecv(uv_udp_t* handle,
 }
 
 
-Local<Object> UDPWrap::Instantiate(Environment* env) {
+Local<Object> UDPWrap::Instantiate(Environment* env, AsyncWrap* parent) {
   // If this assert fires then Initialize hasn't been called yet.
   CHECK_EQ(env->udp_constructor_function().IsEmpty(), false);
-  return env->udp_constructor_function()->NewInstance();
+  EscapableHandleScope scope(env->isolate());
+  Local<Value> ptr = External::New(env->isolate(), parent);
+  return scope.Escape(env->udp_constructor_function()->NewInstance(1, &ptr));
 }
 
 
diff --git a/src/udp_wrap.h b/src/udp_wrap.h
index fea298031ac..9e62d82c31f 100644
--- a/src/udp_wrap.h
+++ b/src/udp_wrap.h
@@ -22,6 +22,7 @@
 #ifndef SRC_UDP_WRAP_H_
 #define SRC_UDP_WRAP_H_
 
+#include "async-wrap.h"
 #include "env.h"
 #include "handle_wrap.h"
 #include "req_wrap.h"
@@ -53,11 +54,11 @@ class UDPWrap: public HandleWrap {
   static void SetBroadcast(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void SetTTL(const v8::FunctionCallbackInfo<v8::Value>& args);
 
-  static v8::Local<v8::Object> Instantiate(Environment* env);
+  static v8::Local<v8::Object> Instantiate(Environment* env, AsyncWrap* parent);
   uv_udp_t* UVHandle();
 
  private:
-  UDPWrap(Environment* env, v8::Handle<v8::Object> object);
+  UDPWrap(Environment* env, v8::Handle<v8::Object> object, AsyncWrap* parent);
 
   static void DoBind(const v8::FunctionCallbackInfo<v8::Value>& args,
                      int family);