root/trunk/whisperlib/common/base/ref_counted.h

// Copyright (c) 2009, Whispersoft s.r.l.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Whispersoft s.r.l. nor the names of its
// 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
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Author: Cosmin Tudorache & Catalin Popescu

#ifndef __COMMON_BASE_REF_COUNTED_H__
#define __COMMON_BASE_REF_COUNTED_H__

#include <whisperlib/common/base/types.h>
#include <whisperlib/common/base/log.h>

template<class C>
class ref_counted {
 public:
  explicit ref_counted(C* data)
      : data_(data),
        ref_count_(0) {
  }
  ~ref_counted() {
    delete data_;
  }
  void IncRef() {
    ++ref_count_;
  }
  void DecRef() {
    --ref_count_;
    DCHECK_GE(ref_count_, 0);
    if ( !ref_count_ ) {
      delete this;
    }
  }
  int ref_count() const {
    return ref_count_;
  }
  C& operator*() const {
    DCHECK(data_ != NULL);
    return *data_;
  }
  C* operator->() const  {
    DCHECK(data_ != NULL);
    return data_;
  }
  C* get() const {
    return data_;
  }
 private:
  C* const data_;
  int ref_count_;
  DISALLOW_EVIL_CONSTRUCTORS(ref_counted);
};

#endif  // __COMMON_BASE_REF_COUNTED_H__