1 // Copyright 2008, Google Inc. All rights reserved. 2 // 3 // Redistribution and use in source and binary forms, with or without 4 // modification, are permitted provided that the following conditions are met: 5 // 6 // 1. Redistributions of source code must retain the above copyright notice, 7 // this list of conditions and the following disclaimer. 8 // 2. Redistributions in binary form must reproduce the above copyright notice, 9 // this list of conditions and the following disclaimer in the documentation 10 // and/or other materials provided with the distribution. 11 // 3. Neither the name of Google Inc. nor the names of its contributors may be 12 // used to endorse or promote products derived from this software without 13 // specific prior written permission. 14 // 15 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 16 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 17 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 18 // EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 19 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 20 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 21 // OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 22 // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 23 // OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 24 // ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 26 #ifndef KML_BASE_REFERENT_H__ 27 #define KML_BASE_REFERENT_H__ 28 29 // This file contains the implementation of the Referent class which holds 30 // the reference counter used by boost::intrusive_ptr. The Referent class 31 // is a base class of all KML DOM Elements and also the base TempFile 32 // class. Neither the Referent class nor the methods here are part of the 33 // libkml public API. 34 35 namespace kmlbase { 36 37 // This class implements the reference count used by boost::intrusive_ptr. 38 class Referent { 39 public: 40 // The constructor only constructs the Referent object. The reference 41 // count is incremented if and when the Referent-derived object is assigned 42 // to a boost::intrusive_ptr. Referent()43 Referent() : ref_count_(0) {} ~Referent()44 virtual ~Referent() {} 45 46 // This method is used by intrusive_ptr_add_ref() to increment the reference 47 // count of a given Referent-derived object. add_ref()48 void add_ref() { 49 ++ref_count_; 50 } 51 52 // This method is used by intrusive_ptr_release() to decrement the reference 53 // count of a given Referent-derived object. release()54 int release() { 55 return --ref_count_; 56 } 57 58 // This is for debugging purposes only. get_ref_count()59 int get_ref_count() const { 60 return ref_count_; 61 } 62 63 private: 64 int ref_count_; 65 }; 66 67 // These declarations are for the implementation of the functions used within 68 // boost::intrusive_ptr to manage Referent-derived objects.. See referent.cc 69 // and boost/intrusive_ptr.hpp. 70 void intrusive_ptr_add_ref(kmlbase::Referent* r); 71 void intrusive_ptr_release(kmlbase::Referent* r); 72 73 } // end namespace kmlbase 74 75 #endif // KML_BASE_REFERENT_H__ 76