electron/shell/browser/api/event_emitter.h
2019-09-30 15:00:47 -07:00

130 lines
4.3 KiB
C++

// Copyright (c) 2014 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#ifndef SHELL_BROWSER_API_EVENT_EMITTER_H_
#define SHELL_BROWSER_API_EVENT_EMITTER_H_
#include <utility>
#include <vector>
#include "base/optional.h"
#include "content/public/browser/browser_thread.h"
#include "electron/shell/common/api/api.mojom.h"
#include "native_mate/wrappable.h"
#include "shell/common/api/event_emitter_caller_deprecated.h"
namespace content {
class RenderFrameHost;
}
namespace mate {
namespace internal {
v8::Local<v8::Object> CreateJSEvent(
v8::Isolate* isolate,
v8::Local<v8::Object> object,
content::RenderFrameHost* sender,
base::Optional<electron::mojom::ElectronBrowser::MessageSyncCallback>
callback);
v8::Local<v8::Object> CreateEmptyJSEvent(v8::Isolate* isolate);
v8::Local<v8::Object> CreateCustomEvent(v8::Isolate* isolate,
v8::Local<v8::Object> object,
v8::Local<v8::Object> event);
v8::Local<v8::Object> CreateEventFromFlags(v8::Isolate* isolate, int flags);
} // namespace internal
// Provide helperers to emit event in JavaScript.
template <typename T>
class EventEmitter : public Wrappable<T> {
public:
typedef std::vector<v8::Local<v8::Value>> ValueArray;
// Make the convinient methods visible:
// https://isocpp.org/wiki/faq/templates#nondependent-name-lookup-members
v8::Isolate* isolate() const { return Wrappable<T>::isolate(); }
v8::Local<v8::Object> GetWrapper() const {
return Wrappable<T>::GetWrapper();
}
v8::MaybeLocal<v8::Object> GetWrapper(v8::Isolate* isolate) const {
return Wrappable<T>::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(flags), args...);
template <typename... Args>
bool EmitWithFlags(base::StringPiece name, int flags, Args&&... args) {
return EmitCustomEvent(name,
internal::CreateEventFromFlags(isolate(), flags),
std::forward<Args>(args)...);
}
// this.emit(name, new Event(), args...);
template <typename... Args>
bool Emit(base::StringPiece name, Args&&... args) {
return EmitWithSender(name, nullptr, base::nullopt,
std::forward<Args>(args)...);
}
// this.emit(name, new Event(sender, message), args...);
template <typename... Args>
bool EmitWithSender(
base::StringPiece name,
content::RenderFrameHost* sender,
base::Optional<electron::mojom::ElectronBrowser::MessageSyncCallback>
callback,
Args&&... args) {
DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
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::CreateJSEvent(
isolate(), wrapper, sender, std::move(callback));
return EmitWithEvent(name, event, std::forward<Args>(args)...);
}
protected:
EventEmitter() {}
private:
// this.emit(name, event, args...);
template <typename... Args>
bool EmitWithEvent(base::StringPiece name,
v8::Local<v8::Object> event,
Args&&... args) {
DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
// It's possible that |this| will be deleted by EmitEvent, so save anything
// we need from |this| before calling EmitEvent.
auto* isolate = this->isolate();
v8::Locker locker(isolate);
v8::HandleScope handle_scope(isolate);
auto context = isolate->GetCurrentContext();
EmitEvent(isolate, GetWrapper(), name, event, std::forward<Args>(args)...);
v8::Local<v8::Value> defaultPrevented;
if (event->Get(context, StringToV8(isolate, "defaultPrevented"))
.ToLocal(&defaultPrevented)) {
return defaultPrevented->BooleanValue(isolate);
}
return false;
}
DISALLOW_COPY_AND_ASSIGN(EventEmitter);
};
} // namespace mate
#endif // SHELL_BROWSER_API_EVENT_EMITTER_H_