async_hooks: C++ Embedder API overhaul

* Fix AsyncHooksGetTriggerAsyncId such it corresponds to
async_hooks.triggerAsyncId and not async_hooks.initTriggerId.
* Use an async_context struct instead of two async_uid values.
  This change was necessary since the fixing
  AsyncHooksGetTriggerAsyncId otherwise makes it impossible to
  get the correct default trigger id. It also prevents an invalid
  triggerAsyncId in MakeCallback.
* Rename async_uid to async_id for consistency

async_hooks: fix AsyncHooksGetTriggerAsyncId

src/async-wrap.cc

@@ -751,7 +751,7 @@ async_uid AsyncHooksGetCurrentId(Isolate* isolate) {
 
 
 async_uid AsyncHooksGetTriggerAsyncId(Isolate* isolate) {
-  return Environment::GetCurrent(isolate)->get_init_trigger_id();
+  return Environment::GetCurrent(isolate)->trigger_id();
 }
 
 async_uid AsyncHooksGetTriggerId(Isolate* isolate) {

src/node.h

@@ -604,7 +604,7 @@ class AsyncResource {
           resource_(isolate, resource),
           trigger_async_id_(trigger_async_id) {
       if (trigger_async_id_ == -1)
-        trigger_async_id_ = AsyncHooksGetTriggerAsyncId(isolate);
+        trigger_async_id_ = Environment::GetCurrent(isolate)->get_init_trigger_id();
 
       uid_ = EmitAsyncInit(isolate, resource, name, trigger_async_id_);
     }

test/addons/async-hooks-id/binding.cc

@@ -0,0 +1,27 @@
+#include "node.h"
+
+namespace {
+
+using v8::FunctionCallbackInfo;
+using v8::Local;
+using v8::Object;
+using v8::Value;
+
+void GetExecutionAsyncId(const FunctionCallbackInfo<Value>& args) {
+  args.GetReturnValue().Set(
+    node::AsyncHooksGetExecutionAsyncId(args.GetIsolate()));
+}
+
+void GetTriggerAsyncId(const FunctionCallbackInfo<Value>& args) {
+  args.GetReturnValue().Set(
+    node::AsyncHooksGetTriggerAsyncId(args.GetIsolate()));
+}
+
+void Initialize(Local<Object> exports) {
+  NODE_SET_METHOD(exports, "getExecutionAsyncId", GetExecutionAsyncId);
+  NODE_SET_METHOD(exports, "getTriggerAsyncId", GetTriggerAsyncId);
+}
+
+}  // namespace
+
+NODE_MODULE(binding, Initialize)

test/addons/async-hooks-id/binding.gyp

@@ -0,0 +1,9 @@
+{
+  'targets': [
+    {
+      'target_name': 'binding',
+      'defines': [ 'V8_DEPRECATION_WARNINGS=1' ],
+      'sources': [ 'binding.cc' ]
+    }
+  ]
+}

test/addons/async-hooks-id/test.js

@@ -0,0 +1,26 @@
+'use strict';
+
+const common = require('../../common');
+const assert = require('assert');
+const binding = require(`./build/${common.buildType}/binding`);
+const async_hooks = require('async_hooks');
+
+assert.strictEqual(
+  binding.getExecutionAsyncId(),
+  async_hooks.executionAsyncId()
+);
+assert.strictEqual(
+  binding.getTriggerAsyncId(),
+  async_hooks.triggerAsyncId()
+);
+
+process.nextTick(common.mustCall(function() {
+  assert.strictEqual(
+    binding.getExecutionAsyncId(),
+    async_hooks.executionAsyncId()
+  );
+  assert.strictEqual(
+    binding.getTriggerAsyncId(),
+    async_hooks.triggerAsyncId()
+  );
+}));

test/addons/async-resource/binding.cc

@@ -92,11 +92,6 @@ void GetResource(const FunctionCallbackInfo<Value>& args) {
   args.GetReturnValue().Set(r->get_resource());
 }
 
-void GetCurrentId(const FunctionCallbackInfo<Value>& args) {
-  args.GetReturnValue().Set(
-    node::AsyncHooksGetExecutionAsyncId(args.GetIsolate()));
-}
-
 void Initialize(Local<Object> exports) {
   NODE_SET_METHOD(exports, "createAsyncResource", CreateAsyncResource);
   NODE_SET_METHOD(exports, "destroyAsyncResource", DestroyAsyncResource);
@@ -105,7 +100,6 @@ void Initialize(Local<Object> exports) {
   NODE_SET_METHOD(exports, "callViaUtf8Name", CallViaUtf8Name);
   NODE_SET_METHOD(exports, "getUid", GetUid);
   NODE_SET_METHOD(exports, "getResource", GetResource);
-  NODE_SET_METHOD(exports, "getCurrentId", GetCurrentId);
 }
 
 }  // namespace

test/addons/async-resource/test.js

@@ -6,6 +6,7 @@ const binding = require(`./build/${common.buildType}/binding`);
 const async_hooks = require('async_hooks');
 
 const kObjectTag = Symbol('kObjectTag');
+const rootAsyncId = async_hooks.executionAsyncId();
 
 const bindingUids = [];
 let expectedTriggerId;
@@ -38,8 +39,6 @@ async_hooks.createHook({
   }
 }).enable();
 
-assert.strictEqual(binding.getCurrentId(), 1);
-
 for (const call of [binding.callViaFunction,
                     binding.callViaString,
                     binding.callViaUtf8Name]) {
@@ -49,14 +48,14 @@ for (const call of [binding.callViaFunction,
       methöd(arg) {
         assert.strictEqual(this, object);
         assert.strictEqual(arg, 42);
-        assert.strictEqual(binding.getCurrentId(), uid);
+        assert.strictEqual(async_hooks.executionAsyncId(), uid);
         return 'baz';
       },
       kObjectTag
     };
 
     if (passedTriggerId === undefined)
-      expectedTriggerId = 1;
+      expectedTriggerId = rootAsyncId;
     else
       expectedTriggerId = passedTriggerId;