electron/shell/common/gin_helper/event_emitter.h

104 lines
3.4 KiB
C++

// Copyright (c) 2019 GitHub, 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_EVENT_EMITTER_H_
#define ELECTRON_SHELL_COMMON_GIN_HELPER_EVENT_EMITTER_H_
#include <utility>
#include <vector>
#include "content/public/browser/browser_thread.h"
#include "electron/shell/common/api/api.mojom.h"
#include "shell/common/gin_helper/event_emitter_caller.h"
#include "shell/common/gin_helper/wrappable.h"
namespace content {
class RenderFrameHost;
}
namespace gin_helper {
namespace internal {
v8::Local<v8::Object> CreateCustomEvent(
v8::Isolate* isolate,
v8::Local<v8::Object> sender = v8::Local<v8::Object>(),
v8::Local<v8::Object> custom_event = v8::Local<v8::Object>());
v8::Local<v8::Object> CreateNativeEvent(
v8::Isolate* isolate,
v8::Local<v8::Object> sender,
content::RenderFrameHost* frame,
electron::mojom::ElectronBrowser::MessageSyncCallback callback);
} // namespace internal
// Provide helperers to emit event in JavaScript.
template <typename T>
class EventEmitter : public gin_helper::Wrappable<T> {
public:
using Base = gin_helper::Wrappable<T>;
using ValueArray = std::vector<v8::Local<v8::Value>>;
// Make the convinient methods visible:
// https://isocpp.org/wiki/faq/templates#nondependent-name-lookup-members
v8::Isolate* isolate() const { return Base::isolate(); }
v8::Local<v8::Object> GetWrapper() const { return Base::GetWrapper(); }
v8::MaybeLocal<v8::Object> GetWrapper(v8::Isolate* isolate) const {
return Base::GetWrapper(isolate);
}
// this.emit(name, event, args...);
template <typename... Args>
bool EmitCustomEvent(base::StringPiece name,
v8::Local<v8::Object> event,
Args&&... args) {
return EmitWithEvent(
name, internal::CreateCustomEvent(isolate(), GetWrapper(), event),
std::forward<Args>(args)...);
}
// this.emit(name, new Event(), args...);
template <typename... Args>
bool Emit(base::StringPiece name, Args&&... args) {
v8::Locker locker(isolate());
v8::HandleScope handle_scope(isolate());
v8::Local<v8::Object> wrapper = GetWrapper();
if (wrapper.IsEmpty())
return false;
v8::Local<v8::Object> event =
internal::CreateCustomEvent(isolate(), wrapper);
return EmitWithEvent(name, event, std::forward<Args>(args)...);
}
// disable copy
EventEmitter(const EventEmitter&) = delete;
EventEmitter& operator=(const EventEmitter&) = delete;
protected:
EventEmitter() {}
private:
// this.emit(name, event, args...);
template <typename... Args>
bool EmitWithEvent(base::StringPiece name,
v8::Local<v8::Object> event,
Args&&... args) {
// It's possible that |this| will be deleted by EmitEvent, so save anything
// we need from |this| before calling EmitEvent.
auto* isolate = this->isolate();
auto context = isolate->GetCurrentContext();
gin_helper::EmitEvent(isolate, GetWrapper(), name, event,
std::forward<Args>(args)...);
v8::Local<v8::Value> defaultPrevented;
if (event->Get(context, gin::StringToV8(isolate, "defaultPrevented"))
.ToLocal(&defaultPrevented)) {
return defaultPrevented->BooleanValue(isolate);
}
return false;
}
};
} // namespace gin_helper
#endif // ELECTRON_SHELL_COMMON_GIN_HELPER_EVENT_EMITTER_H_