[promisehook] Implement PromiseHook

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 8979a7b479312fe0797c5bfefcc1015029f44750..246d5180e92de590a32abece76d3c397d9111103 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2151,7 +2151,7 @@ Isolate::Isolate(bool enable_serializer)
       serializer_enabled_(enable_serializer),
       has_fatal_error_(false),
       initialized_from_snapshot_(false),
-      is_promisehook_enabled_(false),
+      is_promise_hook_enabled_(false),
       is_tail_call_elimination_enabled_(true),
       is_isolate_in_background_(false),
       cpu_profiler_(NULL),
@@ -3168,9 +3168,18 @@ void Isolate::FireCallCompletedCallback() {
   }
 }
 
-void Isolate::EnablePromiseHook() { is_promisehook_enabled_ = true; }
+void Isolate::SetPromiseHook(PromiseHook hook) {
+  is_promise_hook_enabled_ = hook != nullptr;

[adamk, 2016/12/15 08:46:09]

Is there a reason we still need to track this separately? Or could the CSA just
load hook itself and compare it to 0?

[gsathya, 2016/12/15 15:35:33]

I thought the boolean was cleaner. Changed.

[adamk, 2016/12/15 15:43:58]

I prefer this way to avoid having to do extra book-keeping.

+  set_promise_hook(hook);
+}
 
-void Isolate::DisablePromiseHook() { is_promisehook_enabled_ = false; }
+void Isolate::RunPromiseHook(PromiseHookType type, Handle<JSObject> promise,
+                             Handle<Object> parent) {
+  if (!is_promise_hook_enabled_) return;
+  PromiseHook hook = promise_hook();
+  HandleScope scope(this);

[adamk, 2016/12/15 08:46:09]

Where is this called from where there isn't already a HandleScope? Given that it
takes in handles that shouldn't be possible.

[gsathya, 2016/12/15 15:35:33]

I don't create handlescopes in the runtime functions that call this

[adamk, 2016/12/15 15:43:58]

Ah, you should create HandleScopes there :)

+  hook(type, v8::Utils::PromiseToLocal(promise), v8::Utils::ToLocal(parent));
+}
 
 void Isolate::SetPromiseRejectCallback(PromiseRejectCallback callback) {
   promise_reject_callback_ = callback;