3 #ifndef __CDS_CONTAINER_MSQUEUE_H
4 #define __CDS_CONTAINER_MSQUEUE_H
7 #include <cds/intrusive/msqueue.h>
8 #include <cds/container/details/base.h>
10 namespace cds { namespace container {
12 /// MSQueue related definitions
13 /** @ingroup cds_nonintrusive_helper
16 /// Internal statistics
17 template <typename Counter = cds::intrusive::msqueue::stat<>::counter_type >
18 using stat = cds::intrusive::msqueue::stat< Counter >;
20 /// Dummy internal statistics
21 typedef cds::intrusive::msqueue::empty_stat empty_stat;
23 /// MSQueue default type traits
27 typedef CDS_DEFAULT_ALLOCATOR allocator;
30 typedef cds::backoff::empty back_off;
32 /// Item counting feature; by default, disabled. Use \p cds::atomicity::item_counter to enable item counting
33 typedef atomicity::empty_item_counter item_counter;
35 /// Internal statistics (by default, disabled)
37 Possible option value are: \p msqueue::stat, \p msqueue::empty_stat (the default),
38 user-provided class that supports \p %msqueue::stat interface.
40 typedef msqueue::empty_stat stat;
42 /// C++ memory ordering model
44 Can be \p opt::v::relaxed_ordering (relaxed memory model, the default)
45 or \p opt::v::sequential_consistent (sequentially consisnent memory model).
47 typedef opt::v::relaxed_ordering memory_model;
49 /// Alignment of internal queue data. Default is \p opt::cache_line_alignment
50 enum { alignment = opt::cache_line_alignment };
53 /// Metafunction converting option list to \p msqueue::traits
55 This is a wrapper for <tt> cds::opt::make_options< type_traits, Options...> </tt>
56 Supported \p Options are:
57 - opt::allocator - allocator (like \p std::allocator) used for allocating queue nodes. Default is \ref CDS_DEFAULT_ALLOCATOR
58 - opt::back_off - back-off strategy used, default is \p cds::backoff::empty.
59 - opt::item_counter - the type of item counting feature. Default is \p cds::atomicity::empty_item_counter (item counting disabled)
60 To enable item counting use \p cds::atomicity::item_counter
61 - opt::stat - the type to gather internal statistics.
62 Possible statistics types are: \p msqueue::stat, \p msqueue::empty_stat, user-provided class that supports \p %msqueue::stat interface.
63 Default is \p %msqueue::empty_stat.
64 - opt::alignment - the alignment for internal queue data. Default is \p opt::cache_line_alignment
65 - opt::memory_model - C++ memory ordering model. Can be \p opt::v::relaxed_ordering (relaxed memory model, the default)
66 or \p opt::v::sequential_consistent (sequentially consisnent memory model).
68 Example: declare \p %MSQueue with item counting and internal statistics
70 typedef cds::container::MSQueue< cds::gc::HP, Foo,
71 typename cds::container::msqueue::make_traits<
72 cds::opt::item_counte< cds::atomicity::item_counter >,
73 cds::opt::stat< cds::intrusive::msqueue::stat<> >
78 template <typename... Options>
80 # ifdef CDS_DOXYGEN_INVOKED
81 typedef implementation_defined type; ///< Metafunction result
83 typedef typename cds::opt::make_options<
84 typename cds::opt::find_type_traits< traits, Options... >::type
89 } // namespace msqueue
93 template <typename GC, typename T, typename Traits>
98 typedef Traits traits;
100 struct node_type : public intrusive::msqueue::node< gc >
104 node_type( value_type const& val )
108 template <typename... Args>
109 node_type( Args&&... args )
110 : m_value( std::forward<Args>( args )... )
114 typedef typename traits::allocator::template rebind<node_type>::other allocator_type;
115 typedef cds::details::Allocator< node_type, allocator_type > cxx_allocator;
117 struct node_deallocator
119 void operator ()( node_type * pNode )
121 cxx_allocator().Delete( pNode );
125 struct intrusive_traits : public traits
127 typedef cds::intrusive::msqueue::base_hook< cds::opt::gc<gc> > hook;
128 typedef node_deallocator disposer;
129 static CDS_CONSTEXPR const cds::intrusive::opt::link_check_type link_checker = cds::intrusive::msqueue::traits::link_checker;
132 typedef intrusive::MSQueue< gc, node_type, intrusive_traits > type;
137 /// Michael & Scott lock-free queue
138 /** @ingroup cds_nonintrusive_queue
139 It is non-intrusive version of Michael & Scott's queue algorithm based on intrusive implementation
140 \p cds::intrusive::MSQueue.
143 - \p GC - garbage collector type: \p gc::HP, \p gc::DHP
144 - \p T is a type stored in the queue.
145 - \p Traits - queue traits, default is \p msqueue::traits. You can use \p msqueue::make_traits
146 metafunction to make your traits or just derive your traits from \p %msqueue::traits:
148 struct myTraits: public cds::container::msqueue::traits {
149 typedef cds::intrusive::msqueue::stat<> stat;
150 typedef cds::atomicity::item_counter item_counter;
152 typedef cds::container::MSQueue< cds::gc::HP, Foo, myTraits > myQueue;
154 // Equivalent make_traits example:
155 typedef cds::container::MSQueue< cds::gc::HP, Foo,
156 typename cds::container::msqueue::make_traits<
157 cds::opt::stat< cds::container::msqueue::stat<> >,
158 cds::opt::item_counter< cds::atomicity::item_counter >
163 template <typename GC, typename T, typename Traits = cds::container::msqueue::traits>
165 #ifdef CDS_DOXYGEN_INVOKED
166 private intrusive::MSQueue< GC, cds::intrusive::msqueue::node< T >, Traits >
168 private details::make_msqueue< GC, T, Traits >::type
172 typedef details::make_msqueue< GC, T, Traits > maker;
173 typedef typename maker::type base_class;
177 /// Rebind template arguments
178 template <typename GC2, typename T2, typename Traits2>
180 typedef MSQueue< GC2, T2, Traits2> other ; ///< Rebinding result
184 typedef T value_type; ///< Value type stored in the queue
185 typedef typename base_class::gc gc; ///< Garbage collector used
186 typedef typename base_class::back_off back_off; ///< Back-off strategy used
187 typedef typename maker::allocator_type allocator_type; ///< Allocator type used for allocate/deallocate the nodes
188 typedef typename base_class::item_counter item_counter; ///< Item counting policy used
189 typedef typename base_class::stat stat; ///< Internal statistics policy used
190 typedef typename base_class::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
194 typedef typename maker::node_type node_type; ///< queue node type (derived from \p intrusive::msqueue::node)
196 typedef typename maker::cxx_allocator cxx_allocator;
197 typedef typename maker::node_deallocator node_deallocator; // deallocate node
198 typedef typename base_class::node_traits node_traits;
203 static node_type * alloc_node()
205 return cxx_allocator().New();
207 static node_type * alloc_node( value_type const& val )
209 return cxx_allocator().New( val );
211 template <typename... Args>
212 static node_type * alloc_node_move( Args&&... args )
214 return cxx_allocator().MoveNew( std::forward<Args>( args )... );
216 static void free_node( node_type * p )
218 node_deallocator()( p );
221 struct node_disposer {
222 void operator()( node_type * pNode )
227 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
231 /// Initializes empty queue
235 /// Destructor clears the queue
239 /// Enqueues \p val value into the queue.
241 The function makes queue node in dynamic memory calling copy constructor for \p val
242 and then it calls intrusive::MSQueue::enqueue.
243 Returns \p true if success, \p false otherwise.
245 bool enqueue( value_type const& val )
247 scoped_node_ptr p( alloc_node(val) );
248 if ( base_class::enqueue( *p ) ) {
255 /// Enqueues \p data to queue using a functor
257 \p Func is a functor called to create node.
258 The functor \p f takes one argument - a reference to a new node of type \ref value_type :
260 cds:container::MSQueue< cds::gc::HP, Foo > myQueue;
262 myQueue.enqueue_with( [&bar]( Foo& dest ) { dest = bar; } );
265 template <typename Func>
266 bool enqueue_with( Func f )
268 scoped_node_ptr p( alloc_node() );
270 if ( base_class::enqueue( *p )) {
277 /// Enqueues data of type \ref value_type constructed from <tt>std::forward<Args>(args)...</tt>
278 template <typename... Args>
279 bool emplace( Args&&... args )
281 scoped_node_ptr p( alloc_node_move( std::forward<Args>( args )... ) );
282 if ( base_class::enqueue( *p ) ) {
289 /// Synonym for \p enqueue() function
290 bool push( value_type const& val )
292 return enqueue( val );
295 /// Synonym for \p enqueue_with() function
296 template <typename Func>
297 bool push_with( Func f )
299 return enqueue_with( f );
302 /// Dequeues a value from the queue
304 If queue is not empty, the function returns \p true, \p dest contains copy of
305 dequeued value. The assignment operator for type \ref value_type is invoked.
306 If queue is empty, the function returns \p false, \p dest is unchanged.
308 bool dequeue( value_type& dest )
310 return dequeue_with( [&dest]( value_type& src ) { dest = src; } );
313 /// Dequeues a value using a functor
315 \p Func is a functor called to copy dequeued value.
316 The functor takes one argument - a reference to removed node:
318 cds:container::MSQueue< cds::gc::HP, Foo > myQueue;
320 myQueue.dequeue_with( [&bar]( Foo& src ) { bar = std::move( src );});
322 The functor is called only if the queue is not empty.
324 template <typename Func>
325 bool dequeue_with( Func f )
327 typename base_class::dequeue_result res;
328 if ( base_class::do_dequeue( res )) {
329 f( node_traits::to_value_ptr( *res.pNext )->m_value );
330 base_class::dispose_result( res );
336 /// Synonym for \p dequeue() function
337 bool pop( value_type& dest )
339 return dequeue( dest );
342 /// Synonym for \p dequeue_with() function
343 template <typename Func>
344 bool pop_with( Func f )
346 return dequeue_with( f );
351 The function repeatedly calls \ref dequeue until it returns \p nullptr.
358 /// Checks if the queue is empty
361 return base_class::empty();
364 /// Returns queue's item count (see \ref intrusive::MSQueue::size for explanation)
367 return base_class::size();
370 /// Returns reference to internal statistics
371 const stat& statistics() const
373 return base_class::statistics();
377 }} // namespace cds::container
379 #endif // #ifndef __CDS_CONTAINER_MSQUEUE_H