// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "extensions/renderer/object_backed_native_handler.h"

#include <stddef.h>

#include "base/logging.h"
#include "base/memory/linked_ptr.h"
#include "extensions/renderer/console.h"
#include "extensions/renderer/module_system.h"
#include "extensions/renderer/script_context.h"
#include "extensions/renderer/script_context_set.h"
#include "v8/include/v8.h"

namespace extensions {

namespace {
// Key for the base::Bound routed function.
const char* kHandlerFunction = "handler_function";
}  // namespace

ObjectBackedNativeHandler::ObjectBackedNativeHandler(ScriptContext* context)
    : router_data_(context->isolate()),
      context_(context),
      object_template_(context->isolate(),
                       v8::ObjectTemplate::New(context->isolate())) {
}

ObjectBackedNativeHandler::~ObjectBackedNativeHandler() {
}

v8::Local<v8::Object> ObjectBackedNativeHandler::NewInstance() {
  return v8::Local<v8::ObjectTemplate>::New(GetIsolate(), object_template_)
      ->NewInstance();
}

// static
void ObjectBackedNativeHandler::Router(
    const v8::FunctionCallbackInfo<v8::Value>& args) {
  v8::Isolate* isolate = args.GetIsolate();
  v8::HandleScope handle_scope(isolate);
  v8::Local<v8::Object> data = args.Data().As<v8::Object>();
  v8::Local<v8::Context> context = isolate->GetCurrentContext();

  v8::Local<v8::Value> handler_function_value;
  // See comment in header file for why we do this.
  if (!GetPrivate(context, data, kHandlerFunction, &handler_function_value) ||
      handler_function_value->IsUndefined()) {
    ScriptContext* script_context =
        ScriptContextSet::GetContextByV8Context(context);
    console::Error(script_context ? script_context->GetRenderFrame() : nullptr,
                   "Extension view no longer exists");
    return;
  }
  // This CHECK is *important*. Otherwise, we'll go around happily executing
  // something random.  See crbug.com/548273.
  CHECK(handler_function_value->IsExternal());
  static_cast<HandlerFunction*>(
      handler_function_value.As<v8::External>()->Value())->Run(args);
}

void ObjectBackedNativeHandler::RouteFunction(
    const std::string& name,
    const HandlerFunction& handler_function) {
  v8::Isolate* isolate = v8::Isolate::GetCurrent();
  v8::HandleScope handle_scope(isolate);
  v8::Context::Scope context_scope(context_->v8_context());

  v8::Local<v8::Object> data = v8::Object::New(isolate);
  SetPrivate(data, kHandlerFunction,
             v8::External::New(isolate, new HandlerFunction(handler_function)));
  v8::Local<v8::FunctionTemplate> function_template =
      v8::FunctionTemplate::New(isolate, Router, data);
  v8::Local<v8::ObjectTemplate>::New(isolate, object_template_)
      ->Set(isolate, name.c_str(), function_template);
  router_data_.Append(data);
}

v8::Isolate* ObjectBackedNativeHandler::GetIsolate() const {
  return context_->isolate();
}

void ObjectBackedNativeHandler::Invalidate() {
  v8::Isolate* isolate = GetIsolate();
  v8::HandleScope handle_scope(isolate);
  v8::Context::Scope context_scope(context_->v8_context());

  for (size_t i = 0; i < router_data_.Size(); i++) {
    v8::Local<v8::Object> data = router_data_.Get(i);
    v8::Local<v8::Value> handler_function_value;
    CHECK(GetPrivate(data, kHandlerFunction, &handler_function_value));
    delete static_cast<HandlerFunction*>(
        handler_function_value.As<v8::External>()->Value());
    DeletePrivate(data, kHandlerFunction);
  }

  router_data_.Clear();
  object_template_.Reset();

  NativeHandler::Invalidate();
}

void ObjectBackedNativeHandler::SetPrivate(v8::Local<v8::Object> obj,
                                           const char* key,
                                           v8::Local<v8::Value> value) {
  SetPrivate(context_->v8_context(), obj, key, value);
}

// static
void ObjectBackedNativeHandler::SetPrivate(v8::Local<v8::Context> context,
                                           v8::Local<v8::Object> obj,
                                           const char* key,
                                           v8::Local<v8::Value> value) {
  obj->SetPrivate(context, v8::Private::ForApi(context->GetIsolate(),
                                               v8::String::NewFromUtf8(
                                                   context->GetIsolate(), key)),
                  value)
      .FromJust();
}

bool ObjectBackedNativeHandler::GetPrivate(v8::Local<v8::Object> obj,
                                           const char* key,
                                           v8::Local<v8::Value>* result) {
  return GetPrivate(context_->v8_context(), obj, key, result);
}

// static
bool ObjectBackedNativeHandler::GetPrivate(v8::Local<v8::Context> context,
                                           v8::Local<v8::Object> obj,
                                           const char* key,
                                           v8::Local<v8::Value>* result) {
  return obj->GetPrivate(context,
                         v8::Private::ForApi(context->GetIsolate(),
                                             v8::String::NewFromUtf8(
                                                 context->GetIsolate(), key)))
      .ToLocal(result);
}

void ObjectBackedNativeHandler::DeletePrivate(v8::Local<v8::Object> obj,
                                              const char* key) {
  DeletePrivate(context_->v8_context(), obj, key);
}

// static
void ObjectBackedNativeHandler::DeletePrivate(v8::Local<v8::Context> context,
                                              v8::Local<v8::Object> obj,
                                              const char* key) {
  obj->DeletePrivate(context,
                     v8::Private::ForApi(
                         context->GetIsolate(),
                         v8::String::NewFromUtf8(context->GetIsolate(), key)))
      .FromJust();
}

}  // namespace extensions