src/cobalt/script/v8c/v8c_callback_interface.cc

// Copyright 2017 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "cobalt/script/v8c/v8c_callback_interface.h"

#include "base/logging.h"

namespace cobalt {
namespace script {
namespace v8c {

// Helper class to get the actual callable object from a v8::Object
// implementing a callback interface.
// Returns true if a callable was found, and false if not.
v8::MaybeLocal<v8::Object> GetCallableForCallbackInterface(
    v8::Isolate* isolate, v8::Local<v8::Object> implementing_object,
    const char* property_name) {
  DCHECK(!implementing_object.IsEmpty());
  DCHECK(property_name);

  if (implementing_object->IsCallable()) {
    return implementing_object;
  }

  v8::MaybeLocal<v8::Value> maybe_property_value = implementing_object->Get(
      isolate->GetCurrentContext(),
      v8::String::NewFromUtf8(isolate, property_name,
                              v8::NewStringType::kNormal)
          .ToLocalChecked());
  v8::Local<v8::Value> property_value;
  if (!maybe_property_value.ToLocal(&property_value)) {
    return {};
  }

  if (!property_value->IsObject()) {
    return {};
  }
  v8::Local<v8::Object> property_object =
      v8::Local<v8::Object>::Cast(property_value);
  if (!property_object->IsCallable()) {
    return {};
  }

  return property_object;
}

}  // namespace v8c
}  // namespace script
}  // namespace cobalt