electron/shell/common/gin_helper/constructible.h

68 lines
2.5 KiB
C++

// Copyright (c) 2020 Slack Technologies, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#ifndef ELECTRON_SHELL_COMMON_GIN_HELPER_CONSTRUCTIBLE_H_
#define ELECTRON_SHELL_COMMON_GIN_HELPER_CONSTRUCTIBLE_H_
#include "gin/per_isolate_data.h"
#include "gin/wrappable.h"
#include "shell/browser/event_emitter_mixin.h"
#include "shell/common/gin_helper/function_template_extensions.h"
namespace gin_helper {
template <typename T>
class EventEmitterMixin;
// Helper class for Wrappable objects which should be constructible with 'new'
// in JavaScript.
//
// To use, inherit from gin::Wrappable and gin_helper::Constructible, and
// define the static methods New and FillObjectTemplate:
//
// class Example : public gin::Wrappable<Example>,
// public gin_helper::Constructible<Example> {
// public:
// static gin::Handle<Tray> New(...usual gin method arguments...);
// static void FillObjectTemplate(
// v8::Isolate*,
// v8::Local<v8::ObjectTemplate>);
// }
//
// Do NOT define the usual gin::Wrappable::GetObjectTemplateBuilder. It will
// not be called for Constructible classes.
//
// To expose the constructor, call GetConstructor:
//
// gin::Dictionary dict(isolate, exports);
// dict.Set("Example", Example::GetConstructor(context));
template <typename T>
class Constructible {
public:
static v8::Local<v8::Function> GetConstructor(
v8::Local<v8::Context> context) {
v8::Isolate* isolate = context->GetIsolate();
gin::PerIsolateData* data = gin::PerIsolateData::From(isolate);
auto* wrapper_info = &T::kWrapperInfo;
v8::Local<v8::FunctionTemplate> constructor =
data->GetFunctionTemplate(wrapper_info);
if (constructor.IsEmpty()) {
constructor = gin::CreateConstructorFunctionTemplate(
isolate, base::BindRepeating(&T::New));
if (std::is_base_of<EventEmitterMixin<T>, T>::value) {
constructor->Inherit(
gin_helper::internal::GetEventEmitterTemplate(isolate));
}
constructor->InstanceTemplate()->SetInternalFieldCount(
gin::kNumberOfInternalFields);
T::FillObjectTemplate(isolate, constructor->PrototypeTemplate());
data->SetObjectTemplate(wrapper_info, constructor->InstanceTemplate());
data->SetFunctionTemplate(wrapper_info, constructor);
}
return constructor->GetFunction(context).ToLocalChecked();
}
};
} // namespace gin_helper
#endif // ELECTRON_SHELL_COMMON_GIN_HELPER_CONSTRUCTIBLE_H_