threadSafePointerTo.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 threadSafePointerTo.h
 * @author drose
 * @date 2006-04-28
 */

#ifndef THREADSAFEPOINTERTO_H
#define THREADSAFEPOINTERTO_H

#include "pandabase.h"
#include "threadSafePointerToBase.h"

/**
 * This works exactly like PointerTo, except that the object is designed to be
 * thread-safe: it is generally safe to make unprotected assignments to this
 * pointer, in the sense that the last assignment will win and the reference
 * counts will be properly maintained.
 */
template <class T>
class ThreadSafePointerTo : public ThreadSafePointerToBase<T> {
public:
  typedef typename ThreadSafePointerToBase<T>::To To;
PUBLISHED:
  INLINE ThreadSafePointerTo(To *ptr = nullptr);
  INLINE ThreadSafePointerTo(const ThreadSafePointerTo<T> &copy);
  INLINE ~ThreadSafePointerTo();

public:
  INLINE To &operator *() const;
  INLINE To *operator -> () const;
  // MSVC.NET 2005 insists that we use T *, and not To *, here.
  INLINE operator T *() const;

PUBLISHED:
  // When downcasting to a derived class from a
  // ThreadSafePointerTo<BaseClass>, C++ would normally require you to cast
  // twice: once to an actual BaseClass pointer, and then again to your
  // desired pointer.  You can use the handy function p() to avoid this first
  // cast and make your code look a bit cleaner.

  // e.g.  instead of (MyType *)(BaseClass *)ptr, use (MyType *)ptr.p()

  // If your base class is a derivative of TypedObject, you might want to use
  // the DCAST macro defined in typedObject.h instead, e.g.  DCAST(MyType,
  // ptr).  This provides a clean downcast that doesn't require .p() or any
  // double-casting, and it can be run-time checked for correctness.
  INLINE To *p() const;

  INLINE ThreadSafePointerTo<T> &operator = (To *ptr);
  INLINE ThreadSafePointerTo<T> &operator = (const ThreadSafePointerTo<T> &copy);

  // These functions normally wouldn't need to be redefined here, but we do so
  // anyway just to help out interrogate (which doesn't seem to want to
  // automatically export the ThreadSafePointerToBase class).  When this works
  // again in interrogate, we can remove these.
  INLINE bool is_null() const { return ThreadSafePointerToBase<T>::is_null(); }
  INLINE void clear() { ThreadSafePointerToBase<T>::clear(); }
};


/**
 *
 */
template <class T>
class ThreadSafeConstPointerTo : public ThreadSafePointerToBase<T> {
public:
  typedef typename ThreadSafePointerToBase<T>::To To;
PUBLISHED:
  INLINE ThreadSafeConstPointerTo(const To *ptr = nullptr);
  INLINE ThreadSafeConstPointerTo(const ThreadSafePointerTo<T> &copy);
  INLINE ThreadSafeConstPointerTo(const ThreadSafeConstPointerTo<T> &copy);
  INLINE ~ThreadSafeConstPointerTo();

public:
  INLINE const To &operator *() const;
  INLINE const To *operator -> () const;
  INLINE operator const T *() const;

PUBLISHED:
  INLINE const To *p() const;

  INLINE ThreadSafeConstPointerTo<T> &operator = (const To *ptr);
  INLINE ThreadSafeConstPointerTo<T> &operator = (const ThreadSafePointerTo<T> &copy);
  INLINE ThreadSafeConstPointerTo<T> &operator = (const ThreadSafeConstPointerTo<T> &copy);

  // This functions normally wouldn't need to be redefined here, but we do so
  // anyway just to help out interrogate (which doesn't seem to want to
  // automatically export the ThreadSafePointerToBase class).  When this works
  // again in interrogate, we can remove this.
  INLINE void clear() { ThreadSafePointerToBase<T>::clear(); }
};

#define TSPT(type) ThreadSafePointerTo< type >
#define TSCPT(type) ThreadSafeConstPointerTo< type >

#include "threadSafePointerTo.I"

#endif