/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_DOM_EVENTS_SCOPED_EVENT_QUEUE_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_DOM_EVENTS_SCOPED_EVENT_QUEUE_H_

#include "base/memory/scoped_refptr.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/dom/events/event.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_vector.h"
#include "third_party/blink/renderer/platform/heap/persistent.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"

namespace blink {

class CORE_EXPORT ScopedEventQueue {
  USING_FAST_MALLOC(ScopedEventQueue);

 public:
  ScopedEventQueue(const ScopedEventQueue&) = delete;
  ScopedEventQueue& operator=(const ScopedEventQueue&) = delete;
  ~ScopedEventQueue();

  void EnqueueEvent(Event&);
  static ScopedEventQueue* Instance();

  void IncrementScopingLevel();
  void DecrementScopingLevel();
  bool ShouldQueueEvents() const { return scoping_level_ > 0; }

 private:
  ScopedEventQueue();
  static void Initialize();
  void DispatchAllEvents();
  void DispatchEvent(Event&) const;

  Persistent<GCedHeapVector<Member<Event>>> queued_events_;
  unsigned scoping_level_;

  static ScopedEventQueue* instance_;
};

class EventQueueScope {
  STACK_ALLOCATED();

 public:
  EventQueueScope() { ScopedEventQueue::Instance()->IncrementScopingLevel(); }
  EventQueueScope(const EventQueueScope&) = delete;
  EventQueueScope& operator=(const EventQueueScope&) = delete;
  ~EventQueueScope() { ScopedEventQueue::Instance()->DecrementScopingLevel(); }
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_DOM_EVENTS_SCOPED_EVENT_QUEUE_H_
