cef/libcef/common/tracker.h

// Copyright (c) 2012 The Chromium Embedded Framework Authors. All rights
// reserved. Use of this source code is governed by a BSD-style license that
// can be found in the LICENSE file.

#ifndef CEF_LIBCEF_COMMON_TRACKER_H_
#define CEF_LIBCEF_COMMON_TRACKER_H_
#pragma once

#include "include/cef_base.h"

#include "base/synchronization/lock.h"

// Class extended by objects that must be tracked.  After creating a tracked
// object you should add it to the appropriate track manager.
class CefTrackNode {
 public:
  CefTrackNode();
  virtual ~CefTrackNode();

  // Returns true if the object is currently being tracked.
  inline bool IsTracked() { return (track_prev_ || track_next_); }

 private:
  inline CefTrackNode* GetTrackPrev() { return track_prev_; }
  inline void SetTrackPrev(CefTrackNode* base) { track_prev_ = base; }
  inline CefTrackNode* GetTrackNext() { return track_next_; }
  inline void SetTrackNext(CefTrackNode* base) { track_next_ = base; }

  // Insert a new object into the tracking list before this object.
  void InsertTrackPrev(CefTrackNode* object);

  // Insert a new object into the tracking list after this object.
  void InsertTrackNext(CefTrackNode* object);

  // Remove this object from the tracking list.
  void RemoveTracking();

 private:
  CefTrackNode* track_next_ = nullptr;
  CefTrackNode* track_prev_ = nullptr;

  friend class CefTrackManager;
};

// Class used to manage tracked objects.  A single instance of this class
// should be created for each intended usage.  Any objects that have not been
// removed by explicit calls to the Destroy() method will be removed when the
// manager object is destroyed.  A manager object can be created as either a
// member variable of another class or by using lazy initialization:
// base::LazyInstance<CefTrackManager> g_singleton = LAZY_INSTANCE_INITIALIZER;
class CefTrackManager : public CefBaseRefCounted {
 public:
  CefTrackManager();
  ~CefTrackManager() override;

  // Add an object to be tracked by this manager.
  void Add(CefTrackNode* object);

  // Delete an object tracked by this manager.
  bool Delete(CefTrackNode* object);

  // Delete all objects tracked by this manager.
  void DeleteAll();

  // Returns the number of objects currently being tracked.
  inline int GetCount() { return object_count_; }

 private:
  CefTrackNode tracker_;
  int object_count_ = 0;

  base::Lock lock_;

  IMPLEMENT_REFCOUNTING(CefTrackManager);
};

#endif  // CEF_LIBCEF_COMMON_TRACKER_H_