Add toImplSequence()

third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 887 matching lines @@
     }
     return true;
 }
 
 v8::Local<v8::Function> getBoundFunction(v8::Local<v8::Function> function)
 {
     v8::Local<v8::Value> boundFunction = function->GetBoundFunction();
     return boundFunction->IsFunction() ? v8::Local<v8::Function>::Cast(boundFunction) : function;
 }
 
+v8::MaybeLocal<v8::Object> getIterator(v8::Local<v8::Object> object, v8::Isolate* isolate, ExceptionState& exceptionState)

[Yuki, 2016/09/08 06:24:21]

Is it worth doing to make this a general utility as "get an accessor property"?

Then, we can say getAccessorProperty(obj, v8::Symbol::GetIterator(isolate)).

[bashi, 2016/09/08 06:30:49]

That's a good idea but the point of this CL is to provide getIterator defined in
https://tc39.github.io/ecma262/#sec-getiterator

We can generalize it later.

[Yuki, 2016/09/08 08:32:21]

Oops, I thought this is an accessor property, but it's not.
I understand.

By the way, I'm a little uneasy with the name |blink::getIterator|.  Does it
sound a bit too general, especially considering that C++ also supports
iterators?  I don't have a good idea, though.  Off the top of my head,
getEsIterator?  esGetIterator?  where es = ECMAScript.

[Yuki, 2016/09/08 08:32:21]

Please make v8::Isolate* as the first argument.

[bashi, 2016/09/09 00:54:22]

Done.

+{
+    v8::Local<v8::Context> context = isolate->GetCurrentContext();
+    v8::Local<v8::Value> iteratorGetter;
+    if (!object->Get(context, v8::Symbol::GetIterator(isolate)).ToLocal(&iteratorGetter)) {
+        return v8::MaybeLocal<v8::Object>();

[haraken, 2016/09/08 09:32:08]

Don't we need to throw an exception here?

[bashi, 2016/09/09 00:54:22]

No. IIRC, !ToLocal() means that v8 already thrown an exception.

+    }
+    if (!iteratorGetter->IsFunction()) {
+        exceptionState.throwTypeError("Iterator getter is not callable.");
+        return v8::MaybeLocal<v8::Object>();
+    }
+
+    v8::Local<v8::Function> getterFunction = iteratorGetter.As<v8::Function>();
+    v8::Local<v8::Value> iterator;
+    if (!getterFunction->Call(context, object, 0, nullptr).ToLocal(&iterator)) {
+        return v8::MaybeLocal<v8::Object>();

[haraken, 2016/09/08 09:32:08]

Ditto.

+    }
+    if (!iterator->IsObject()) {
+        exceptionState.throwTypeError("Iterator is not an object.");
+        return v8::MaybeLocal<v8::Object>();
+    }
+    return v8::MaybeLocal<v8::Object>(iterator.As<v8::Object>());
+}
+
 bool addHiddenValueToArray(v8::Isolate* isolate, v8::Local<v8::Object> object, v8::Local<v8::Value> value, int arrayIndex)
 {
     ASSERT(!value.IsEmpty());
     v8::Local<v8::Value> arrayValue = object->GetInternalField(arrayIndex);
     if (arrayValue->IsNull() || arrayValue->IsUndefined()) {
         arrayValue = v8::Array::New(isolate);
         object->SetInternalField(arrayIndex, arrayValue);
     }
 
     v8::Local<v8::Array> array = v8::Local<v8::Array>::Cast(arrayValue);
@@ skipping 45 matching lines @@
     return frame->script().isolate();
 }
 
 v8::Local<v8::Value> freezeV8Object(v8::Local<v8::Value> value, v8::Isolate* isolate)
 {
     value.As<v8::Object>()->SetIntegrityLevel(isolate->GetCurrentContext(), v8::IntegrityLevel::kFrozen).ToChecked();
     return value;
 }
 
 } // namespace blink