3 #ifndef __CDS_CONTAINER_MSQUEUE_H
4 #define __CDS_CONTAINER_MSQUEUE_H
7 #include <functional> // ref
8 #include <cds/intrusive/msqueue.h>
9 #include <cds/container/details/base.h>
11 namespace cds { namespace container {
13 /// MSQueue related definitions
14 /** @ingroup cds_nonintrusive_helper
17 /// Internal statistics
18 template <typename Counter = cds::intrusive::msqueue::stat<>::counter_type >
19 using stat = cds::intrusive::msqueue::stat< Counter >;
21 /// Dummy internal statistics
22 typedef cds::intrusive::msqueue::empty_stat empty_stat;
24 /// MSQueue default type traits
28 typedef CDS_DEFAULT_ALLOCATOR allocator;
31 typedef cds::backoff::empty back_off;
33 /// Item counting feature; by default, disabled. Use \p cds::atomicity::item_counter to enable item counting
34 typedef atomicity::empty_item_counter item_counter;
36 /// Internal statistics (by default, disabled)
38 Possible option value are: \p msqueue::stat, \p msqueue::empty_stat (the default),
39 user-provided class that supports \p %msqueue::stat interface.
41 typedef msqueue::empty_stat stat;
43 /// C++ memory ordering model
45 Can be \p opt::v::relaxed_ordering (relaxed memory model, the default)
46 or \p opt::v::sequential_consistent (sequentially consisnent memory model).
48 typedef opt::v::relaxed_ordering memory_model;
50 /// Alignment of internal queue data. Default is \p opt::cache_line_alignment
51 enum { alignment = opt::cache_line_alignment };
54 /// Metafunction converting option list to \p msqueue::traits
56 This is a wrapper for <tt> cds::opt::make_options< type_traits, Options...> </tt>
57 Supported \p Options are:
58 - opt::allocator - allocator (like \p std::allocator) used for allocating queue nodes. Default is \ref CDS_DEFAULT_ALLOCATOR
59 - opt::back_off - back-off strategy used, default is \p cds::backoff::empty.
60 - opt::item_counter - the type of item counting feature. Default is \p cds::atomicity::empty_item_counter (item counting disabled)
61 To enable item counting use \p cds::atomicity::item_counter
62 - opt::stat - the type to gather internal statistics.
63 Possible statistics types are: \p msqueue::stat, \p msqueue::empty_stat, user-provided class that supports \p %msqueue::stat interface.
64 Default is \p %msqueue::empty_stat.
65 - opt::alignment - the alignment for internal queue data. Default is \p opt::cache_line_alignment
66 - opt::memory_model - C++ memory ordering model. Can be \p opt::v::relaxed_ordering (relaxed memory model, the default)
67 or \p opt::v::sequential_consistent (sequentially consisnent memory model).
69 Example: declare \p %MSQueue with item counting and internal statistics
71 typedef cds::container::MSQueue< cds::gc::HP, Foo,
72 typename cds::container::msqueue::make_traits<
73 cds::opt::item_counte< cds::atomicity::item_counter >,
74 cds::opt::stat< cds::intrusive::msqueue::stat<> >
79 template <typename... Options>
81 # ifdef CDS_DOXYGEN_INVOKED
82 typedef implementation_defined type; ///< Metafunction result
84 typedef typename cds::opt::make_options<
85 typename cds::opt::find_type_traits< traits, Options... >::type
90 } // namespace msqueue
94 template <typename GC, typename T, typename Traits>
99 typedef Traits traits;
101 struct node_type: public intrusive::msqueue::node< gc >
105 node_type( value_type const& val )
109 template <typename... Args>
110 node_type( Args&&... args )
111 : m_value( std::forward<Args>(args)...)
115 typedef typename traits::allocator::template rebind<node_type>::other allocator_type;
116 typedef cds::details::Allocator< node_type, allocator_type > cxx_allocator;
118 struct node_deallocator
120 void operator ()( node_type * pNode )
122 cxx_allocator().Delete( pNode );
126 struct intrusive_traits : public traits
128 typedef cds::intrusive::base_hook< cds::opt::gc<gc> > hook;
129 typedef node_deallocator disposer;
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>
165 #ifdef CDS_DOXYGEN_INVOKED
166 intrusive::MSQueue< GC, cds::intrusive::msqueue::node< T >, Traits >
168 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
193 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 /// Returns queue's item count (see \ref intrusive::MSQueue::size for explanation)
242 return base_class::size();
245 /// Returns reference to internal statistics
246 const stat& statistics() const
248 return base_class::statistics();
251 /// Enqueues \p val value into the queue.
253 The function makes queue node in dynamic memory calling copy constructor for \p val
254 and then it calls intrusive::MSQueue::enqueue.
255 Returns \p true if success, \p false otherwise.
257 bool enqueue( value_type const& val )
259 scoped_node_ptr p( alloc_node(val) );
260 if ( base_class::enqueue( *p ) ) {
267 /// Enqueues \p data to queue using a functor
269 \p Func is a functor called to create node.
270 The functor \p f takes one argument - a reference to a new node of type \ref value_type:
272 cds:container::MSQueue< cds::gc::HP, Foo > myQueue;
274 myQueue.enqueue_with( [&bar]( Foo& dest ) { dest = bar; } );
277 template <typename Func>
278 bool enqueue_with( Func f )
280 scoped_node_ptr p( alloc_node() );
282 if ( base_class::enqueue( *p )) {
289 /// Enqueues data of type \ref value_type constructed from <tt>std::forward<Args>(args)...</tt>
290 template <typename... Args>
291 bool emplace( Args&&... args )
293 scoped_node_ptr p( alloc_node_move( std::forward<Args>( args )... ) );
294 if ( base_class::enqueue( *p ) ) {
301 /// Synonym for \ref enqueue function
302 bool push( value_type const& val )
304 return enqueue( val );
307 /// Synonym for \p enqueue_with() function
308 template <typename Func>
309 bool push_with( Func f )
311 return enqueue_with( f );
314 /// Dequeues a value using a functor
316 \p Func is a functor called to copy dequeued value.
317 The functor takes one argument - a reference to removed node:
319 cds:container::MSQueue< cds::gc::HP, Foo > myQueue;
321 myQueue.dequeue_with( [&bar]( Foo& src ) { bar = std::move( src );});
323 The functor is called only is the queue is not empty.
325 template <typename Func>
326 bool dequeue_with( Func f )
328 typename base_class::dequeue_result res;
329 if ( base_class::do_dequeue( res )) {
330 f( node_traits::to_value_ptr( *res.pNext )->m_value );
331 base_class::dispose_result( res );
337 /// Dequeues a value from the queue
339 If queue is not empty, the function returns \p true, \p dest contains copy of
340 dequeued value. The assignment operator for type \ref value_type is invoked.
341 If queue is empty, the function returns \p false, \p dest is unchanged.
343 bool dequeue( value_type& dest )
345 typedef cds::details::trivial_assign<value_type, value_type> functor;
346 return dequeue( dest, functor() );
349 /// Synonym for \ref dequeue function
350 bool pop( value_type& dest )
352 return dequeue( dest );
355 /// Synonym for \p dequeue_with() function
356 template <typename Func>
357 bool pop_with( Func f )
359 return dequeue_with( f );
362 /// Checks if the queue is empty
365 return base_class::empty();
370 The function repeatedly calls \ref dequeue until it returns \p nullptr.
378 }} // namespace cds::container
380 #endif // #ifndef __CDS_CONTAINER_MSQUEUE_H