1 ////////////////////////////////////////////////////////////////////////////// 2 // 3 // (C) Copyright Ion Gaztanaga 2006-2012. Distributed under the Boost 4 // Software License, Version 1.0. (See accompanying file 5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 6 // 7 // See http://www.boost.org/libs/interprocess for documentation. 8 // 9 ////////////////////////////////////////////////////////////////////////////// 10 11 #include <boost/interprocess/detail/config_begin.hpp> 12 #include <boost/interprocess/detail/workaround.hpp> 13 //[doc_intrusive 14 #include <boost/interprocess/managed_shared_memory.hpp> 15 #include <boost/interprocess/smart_ptr/intrusive_ptr.hpp> 16 //<- 17 #include "../test/get_process_id_name.hpp" 18 //-> 19 20 using namespace boost::interprocess; 21 22 namespace N { 23 24 //A class that has an internal reference count 25 class reference_counted_class 26 { 27 private: 28 //Non-copyable 29 reference_counted_class(const reference_counted_class &); 30 //Non-assignable 31 reference_counted_class & operator=(const reference_counted_class &); 32 //A typedef to save typing 33 typedef managed_shared_memory::segment_manager segment_manager; 34 //This is the reference count 35 unsigned int m_use_count; 36 //The segment manager allows deletion from shared memory segment 37 offset_ptr<segment_manager> mp_segment_manager; 38 39 public: 40 //Constructor reference_counted_class(segment_manager * s_mngr)41 reference_counted_class(segment_manager *s_mngr) 42 : m_use_count(0), mp_segment_manager(s_mngr){} 43 //Destructor ~reference_counted_class()44 ~reference_counted_class(){} 45 46 public: 47 //Returns the reference count use_count() const48 unsigned int use_count() const 49 { return m_use_count; } 50 51 //Adds a reference intrusive_ptr_add_ref(reference_counted_class * p)52 inline friend void intrusive_ptr_add_ref(reference_counted_class * p) 53 { ++p->m_use_count; } 54 55 //Releases a reference intrusive_ptr_release(reference_counted_class * p)56 inline friend void intrusive_ptr_release(reference_counted_class * p) 57 { if(--p->m_use_count == 0) p->mp_segment_manager->destroy_ptr(p); } 58 }; 59 60 } //namespace N { 61 62 //A class that has an intrusive pointer to reference_counted_class 63 class intrusive_ptr_owner 64 { 65 typedef intrusive_ptr<N::reference_counted_class, 66 offset_ptr<void> > intrusive_ptr_t; 67 intrusive_ptr_t m_intrusive_ptr; 68 69 public: 70 //Takes a pointer to the reference counted class intrusive_ptr_owner(N::reference_counted_class * ptr)71 intrusive_ptr_owner(N::reference_counted_class *ptr) 72 : m_intrusive_ptr(ptr){} 73 }; 74 main()75int main() 76 { 77 //Remove shared memory on construction and destruction 78 struct shm_remove 79 { 80 //<- 81 #if 1 82 shm_remove() { shared_memory_object::remove(test::get_process_id_name()); } 83 ~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); } 84 #else 85 //-> 86 shm_remove() { shared_memory_object::remove("MySharedMemory"); } 87 ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); } 88 //<- 89 #endif 90 //-> 91 } remover; 92 //<- 93 (void)remover; 94 //-> 95 96 //Create shared memory 97 //<- 98 #if 1 99 managed_shared_memory shmem(create_only, test::get_process_id_name(), 10000); 100 #else 101 //-> 102 managed_shared_memory shmem(create_only, "MySharedMemory", 10000); 103 //<- 104 #endif 105 //-> 106 107 //Create the unique reference counted object in shared memory 108 N::reference_counted_class *ref_counted = 109 shmem.construct<N::reference_counted_class> 110 ("ref_counted")(shmem.get_segment_manager()); 111 112 //Create an array of ten intrusive pointer owners in shared memory 113 intrusive_ptr_owner *intrusive_owner_array = 114 shmem.construct<intrusive_ptr_owner> 115 (anonymous_instance)[10](ref_counted); 116 117 //Now test that reference count is ten 118 if(ref_counted->use_count() != 10) 119 return 1; 120 121 //Now destroy the array of intrusive pointer owners 122 //This should destroy every intrusive_ptr and because of 123 //that reference_counted_class will be destroyed 124 shmem.destroy_ptr(intrusive_owner_array); 125 126 //Now the reference counted object should have been destroyed 127 if(shmem.find<intrusive_ptr_owner>("ref_counted").first) 128 return 1; 129 //Success! 130 return 0; 131 } 132 //] 133 #include <boost/interprocess/detail/config_end.hpp> 134