nodeCachedReferenceCount.h

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file nodeCachedReferenceCount.h
 * @author drose
 * @date 2005-05-07
 */
 
#ifndef NODECACHEDREFERENCECOUNT_H
#define NODECACHEDREFERENCECOUNT_H
 
#include "pandabase.h"
 
#include "cachedTypedWritableReferenceCount.h"
#include "nodeReferenceCount.h" // for node_unref_delete()
 
/**
 * This class further specializes CachedTypedWritableReferenceCount to also
 * add a node_ref_count, for the purposes of counting the number of times the
 * object is referenced by a "node", presumably a PandaNode.
 *
 * This essentially combines the functionality of NodeReferenceCount and
 * CachedTypedWritableReferenceCount, so that a derivative of this object
 * actually has three counters: the standard reference count, the "cache"
 * reference count, and the "node" reference count.  Rather than multiply
 * inheriting from the two reference count classes, we inherit only from
 * CachedTypedWritableReferenceCount and simply duplicate the functionality of
 * NodeReferenceCount, to avoid all of the problems associated with multiple
 * inheritance.
 *
 * The intended design is to use this as a base class for RenderState and
 * TransformState, both of which are held by PandaNodes, and also have caches
 * which are independently maintained.  By keeping track of how many nodes
 * hold a pointer to a particular object, we can classify each object into
 * node-referenced, cache-referenced, or other, which is primarily useful for
 * PStats reporting.
 *
 * As with CachedTypedWritableReferenceCount's cache_ref() and cache_unref(),
 * the new methods node_ref() and node_unref() automatically increment and
 * decrement the primary reference count as well.  In this case, however,
 * there does exist a NodePointerTo<> class to maintain the node_ref counters
 * automatically.
 */
class EXPCL_PANDA_PUTIL NodeCachedReferenceCount : public CachedTypedWritableReferenceCount {
protected:
  INLINE NodeCachedReferenceCount();
  INLINE NodeCachedReferenceCount(const NodeCachedReferenceCount &copy);
  INLINE void operator = (const NodeCachedReferenceCount &copy);
  INLINE ~NodeCachedReferenceCount();
 
PUBLISHED:
  INLINE int get_node_ref_count() const;
  INLINE void node_ref() const;
  INLINE bool node_unref() const;
  INLINE bool test_ref_count_integrity() const;
 
  enum Referenced {
    R_node  = 0x001,
    R_cache = 0x002,
  };
 
  INLINE int get_referenced_bits() const;
 
protected:
  INLINE void node_unref_only() const;
  bool do_test_ref_count_integrity() const;
 
private:
  AtomicAdjust::Integer _node_ref_count;
 
public:
  static TypeHandle get_class_type() {
    return _type_handle;
  }
 
  static void init_type() {
    CachedTypedWritableReferenceCount::init_type();
    register_type(_type_handle, "NodeCachedReferenceCount",
                  CachedTypedWritableReferenceCount::get_class_type());
  }
 
private:
  static TypeHandle _type_handle;
};
 
#include "nodeCachedReferenceCount.I"
 
#endif