text: // Copyright (c) 2019 GitHub, Inc.
  // Use of this source code is governed by the MIT license that can be
  // found in the LICENSE file.
  
  #include "shell/common/gin_helper/event_emitter.h"
  
  #include "content/public/browser/render_frame_host.h"
  #include "shell/browser/api/event.h"
  #include "shell/common/gin_helper/dictionary.h"
  #include "shell/common/gin_helper/object_template_builder.h"
  #include "ui/events/event_constants.h"
  
  namespace gin_helper {
  
  namespace internal {
  
  namespace {
  
  v8::Persistent<v8::ObjectTemplate> event_template;
  
  void PreventDefault(gin_helper::Arguments* args) {
    Dictionary self;
    if (args->GetHolder(&self))
      self.Set("defaultPrevented", true);
  }
  
  }  // namespace
  
  v8::Local<v8::Object> CreateEvent(v8::Isolate* isolate,
                                    v8::Local<v8::Object> sender,
                                    v8::Local<v8::Object> custom_event) {
    if (event_template.IsEmpty()) {
      event_template.Reset(
          isolate,
          ObjectTemplateBuilder(isolate, v8::ObjectTemplate::New(isolate))
              .SetMethod("preventDefault", &PreventDefault)
              .Build());
    }
  
    v8::Local<v8::Context> context = isolate->GetCurrentContext();
    CHECK(!context.IsEmpty());
    v8::Local<v8::Object> event =
        v8::Local<v8::ObjectTemplate>::New(isolate, event_template)
            ->NewInstance(context)
            .ToLocalChecked();
    if (!sender.IsEmpty())
      Dictionary(isolate, event).Set("sender", sender);
    if (!custom_event.IsEmpty())
      event->SetPrototype(context, custom_event).IsJust();
    return event;
  }
  
  v8::Local<v8::Object> CreateEventFromFlags(v8::Isolate* isolate, int flags) {
    const int mouse_button_flags =
        (ui::EF_RIGHT_MOUSE_BUTTON | ui::EF_LEFT_MOUSE_BUTTON |
         ui::EF_MIDDLE_MOUSE_BUTTON | ui::EF_BACK_MOUSE_BUTTON |
         ui::EF_FORWARD_MOUSE_BUTTON);
    const int is_mouse_click = static_cast<bool>(flags & mouse_button_flags);
    Dictionary obj = gin::Dictionary::CreateEmpty(isolate);
    obj.Set("shiftKey", static_cast<bool>(flags & ui::EF_SHIFT_DOWN));
    obj.Set("ctrlKey", static_cast<bool>(flags & ui::EF_CONTROL_DOWN));
    obj.Set("altKey", static_cast<bool>(flags & ui::EF_ALT_DOWN));
    obj.Set("metaKey", static_cast<bool>(flags & ui::EF_COMMAND_DOWN));
    obj.Set("triggeredByAccelerator", !is_mouse_click);
    return obj.GetHandle();
  }
  
  v8::Local<v8::Object> CreateNativeEvent(
      v8::Isolate* isolate,
      v8::Local<v8::Object> sender,
      content::RenderFrameHost* frame,
      electron::mojom::ElectronBrowser::MessageSyncCallback callback) {
    v8::Local<v8::Object> event;
    if (frame && callback) {
      gin::Handle<Event> native_event = Event::Create(isolate);
      native_event->SetCallback(std::move(callback));
      event = v8::Local<v8::Object>::Cast(native_event.ToV8());
    } else {
      // No need to create native event if we do not need to send reply.
      event = CreateEvent(isolate);
    }
  
    Dictionary dict(isolate, event);
    dict.Set("sender", sender);
    // Should always set frameId even when callback is null.
    if (frame)
      dict.Set("frameId", frame->GetRoutingID());
    return event;
  }
  
  }  // namespace internal
  
  }  // namespace gin_helper
  