3 #ifndef CDSLIB_INTRUSIVE_IMPL_LAZY_LIST_H
4 #define CDSLIB_INTRUSIVE_IMPL_LAZY_LIST_H
6 #include <mutex> // unique_lock
7 #include <cds/intrusive/details/lazy_list_base.h>
9 namespace cds { namespace intrusive {
11 /// Lazy ordered single-linked list
12 /** @ingroup cds_intrusive_list
13 \anchor cds_intrusive_LazyList_hp
15 Usually, ordered single-linked list is used as a building block for the hash table implementation.
16 The complexity of searching is <tt>O(N)</tt>.
19 - [2005] Steve Heller, Maurice Herlihy, Victor Luchangco, Mark Moir, William N. Scherer III, and Nir Shavit
20 "A Lazy Concurrent List-Based Set Algorithm"
22 The lazy list is based on an optimistic locking scheme for inserts and removes,
23 eliminating the need to use the equivalent of an atomically markable
24 reference. It also has a novel wait-free membership \p find operation
25 that does not need to perform cleanup operations and is more efficient.
28 - \p GC - Garbage collector used. Note the \p GC must be the same as the GC used for item type \p T (see lazy_list::node).
29 - \p T - type to be stored in the list. The type must be based on lazy_list::node (for lazy_list::base_hook)
30 or it must have a member of type lazy_list::node (for lazy_list::member_hook).
31 - \p Traits - type traits. See lazy_list::traits for explanation.
32 It is possible to declare option-based list with cds::intrusive::lazy_list::make_traits metafunction istead of \p Traits template
33 argument. For example, the following traits-based declaration of \p gc::HP lazy list
35 #include <cds/intrusive/lazy_list_hp.h>
36 // Declare item stored in your list
37 struct item: public cds::intrusive::lazy_list::node< cds::gc::HP >
40 // Declare comparator for the item
41 struct my_compare { ... }
44 struct my_traits: public cds::intrusive::lazy_list::traits
46 typedef cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::HP > > hook;
47 typedef my_compare compare;
50 // Declare traits-based list
51 typedef cds::intrusive::LazyList< cds::gc::HP, item, my_traits > traits_based_list;
53 is equivalent for the following option-based list
55 #include <cds/intrusive/lazy_list_hp.h>
57 // item struct and my_compare are the same
59 // Declare option-based list
60 typedef cds::intrusive::LazyList< cds::gc::HP, item,
61 typename cds::intrusive::lazy_list::make_traits<
62 cds::intrusive::opt::hook< cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::HP > > > // hook option
63 ,cds::intrusive::opt::compare< my_compare > // item comparator option
69 There are different specializations of this template for each garbage collecting schema used.
70 You should select GC needed and include appropriate .h-file:
71 - for gc::HP: \code #include <cds/intrusive/lazy_list_hp.h> \endcode
72 - for gc::DHP: \code #include <cds/intrusive/lazy_list_dhp.h> \endcode
73 - for gc::nogc: \code #include <cds/intrusive/lazy_list_nogc.h> \endcode
74 - for \ref cds_urcu_type "RCU" - see \ref cds_intrusive_LazyList_rcu "LazyList RCU specialization"
76 Then, you should incorporate lazy_list::node into your struct \p T and provide
77 appropriate \p lazy_list::traits::hook in your \p Traits template parameters. Usually, for \p Traits
78 a struct based on \p lazy_list::traits should be defined.
80 Example for gc::DHP and base hook:
82 // Include GC-related lazy list specialization
83 #include <cds/intrusive/lazy_list_dhp.h>
85 // Data stored in lazy list
86 struct my_data: public cds::intrusive::lazy_list::node< cds::gc::DHP >
95 // my_data comparing functor
97 int operator()( const my_data& d1, const my_data& d2 )
99 return d1.strKey.compare( d2.strKey );
102 int operator()( const my_data& d, const std::string& s )
104 return d.strKey.compare(s);
107 int operator()( const std::string& s, const my_data& d )
109 return s.compare( d.strKey );
114 struct my_traits: public cds::intrusive::lazy_list::traits
116 typedef cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::DHP > > hook;
117 typedef my_data_cmp compare;
121 typedef cds::intrusive::LazyList< cds::gc::DHP, my_data, my_traits > traits_based_list;
124 Equivalent option-based code:
126 // GC-related specialization
127 #include <cds/intrusive/lazy_list_dhp.h>
136 // Declare option-based list
137 typedef cds::intrusive::LazyList< cds::gc::DHP
139 , typename cds::intrusive::lazy_list::make_traits<
140 cds::intrusive::opt::hook< cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::DHP > > >
141 ,cds::intrusive::opt::compare< my_data_cmp >
150 #ifdef CDS_DOXYGEN_INVOKED
151 ,class Traits = lazy_list::traits
159 typedef GC gc; ///< Garbage collector
160 typedef T value_type; ///< type of value stored in the list
161 typedef Traits traits; ///< Traits template parameter
163 typedef typename traits::hook hook; ///< hook type
164 typedef typename hook::node_type node_type; ///< node type
166 # ifdef CDS_DOXYGEN_INVOKED
167 typedef implementation_defined key_comparator ; ///< key comparison functor based on opt::compare and opt::less option setter.
169 typedef typename opt::details::make_comparator< value_type, traits >::type key_comparator;
172 typedef typename traits::disposer disposer; ///< disposer
173 typedef typename get_node_traits< value_type, node_type, hook>::type node_traits; ///< node traits
174 typedef typename lazy_list::get_link_checker< node_type, traits::link_checker >::type link_checker; ///< link checker
176 typedef typename traits::back_off back_off ; ///< back-off strategy
177 typedef typename traits::item_counter item_counter ; ///< Item counting policy used
178 typedef typename traits::memory_model memory_model; ///< C++ memory ordering (see \p lazy_list::traits::memory_model)
180 typedef typename gc::template guarded_ptr< value_type > guarded_ptr; ///< Guarded pointer
183 // Rebind traits (split-list support)
184 template <typename... Options>
185 struct rebind_traits {
189 , typename cds::opt::make_options< traits, Options...>::type
195 typedef typename node_type::marked_ptr marked_node_ptr; ///< Node marked pointer
196 typedef node_type * auxiliary_head; ///< Auxiliary head type (for split-list support)
203 item_counter m_ItemCounter ; ///< Item counter
206 struct clean_disposer {
207 void operator()( value_type * p )
209 lazy_list::node_cleaner<gc, node_type, memory_model>()( node_traits::to_node_ptr( p ) );
214 /// Position pointer for item search
216 node_type * pPred ; ///< Previous node
217 node_type * pCur ; ///< Current node
219 typename gc::template GuardArray<2> guards ; ///< Guards array
226 /// Locks nodes \p pPred and \p pCur
229 pPred->m_Lock.lock();
233 /// Unlocks nodes \p pPred and \p pCur
236 pCur->m_Lock.unlock();
237 pPred->m_Lock.unlock();
241 class auto_lock_position {
244 auto_lock_position( position& pos )
249 ~auto_lock_position()
258 void link_node( node_type * pNode, node_type * pPred, node_type * pCur )
260 assert( pPred->m_pNext.load(memory_model::memory_order_relaxed).ptr() == pCur );
262 pNode->m_pNext.store( marked_node_ptr(pCur), memory_model::memory_order_release );
263 pPred->m_pNext.store( marked_node_ptr(pNode), memory_model::memory_order_release );
266 void unlink_node( node_type * pPred, node_type * pCur, node_type * pHead )
268 assert( pPred->m_pNext.load(memory_model::memory_order_relaxed).ptr() == pCur );
270 node_type * pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr();
271 //pCur->m_pNext.store( marked_node_ptr( pNext, 1), memory_model::memory_order_release) ; // logically deleting
272 pCur->m_pNext.store( marked_node_ptr( pHead, 1 ), memory_model::memory_order_release ) ; // logical removal + back-link for search
273 pPred->m_pNext.store( marked_node_ptr( pNext ), memory_model::memory_order_release); // physically deleting
274 //pCur->m_pNext.store( marked_node_ptr( pHead, 1 ), memory_model::memory_order_release ) ; // back-link for search
277 void retire_node( node_type * pNode )
279 assert( pNode != nullptr );
280 gc::template retire<clean_disposer>( node_traits::to_value_ptr( *pNode ) );
286 template <bool IsConst>
289 friend class LazyList;
292 value_type * m_pNode;
293 typename gc::Guard m_Guard;
297 assert( m_pNode != nullptr );
300 typename gc::Guard g;
301 node_type * pCur = node_traits::to_node_ptr( m_pNode );
302 if ( pCur->m_pNext.load( memory_model::memory_order_relaxed ).ptr() != nullptr ) { // if pCur is not tail node
305 pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr();
306 g.assign( node_traits::to_value_ptr( pNext ));
307 } while ( pNext != pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr() );
309 m_pNode = m_Guard.assign( g.template get<value_type>() );
316 if ( m_pNode != nullptr ) {
317 typename gc::Guard g;
318 node_type * pNode = node_traits::to_node_ptr( m_pNode );
320 // Dummy tail node could not be marked
321 while ( pNode->is_marked() ) {
322 node_type * p = pNode->m_pNext.load(memory_model::memory_order_relaxed).ptr();
323 g.assign( node_traits::to_value_ptr( p ));
324 if ( p == pNode->m_pNext.load(memory_model::memory_order_relaxed).ptr() )
327 if ( pNode != node_traits::to_node_ptr( m_pNode ) )
328 m_pNode = m_Guard.assign( g.template get<value_type>() );
332 iterator_type( node_type * pNode )
334 m_pNode = m_Guard.assign( node_traits::to_value_ptr( pNode ));
339 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
340 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
346 iterator_type( iterator_type const& src )
349 m_pNode = m_Guard.assign( src.m_pNode );
355 value_ptr operator ->() const
360 value_ref operator *() const
362 assert( m_pNode != nullptr );
367 iterator_type& operator ++()
374 iterator_type& operator = (iterator_type const& src)
376 m_pNode = src.m_pNode;
377 m_Guard.assign( m_pNode );
382 bool operator ==(iterator_type<C> const& i ) const
384 return m_pNode == i.m_pNode;
387 bool operator !=(iterator_type<C> const& i ) const
389 return m_pNode != i.m_pNode;
397 The forward iterator for lazy list has some features:
398 - it has no post-increment operator
399 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
400 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
401 may be thrown if a limit of guard count per thread is exceeded.
402 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
403 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
404 deleting operations it is no guarantee that you iterate all item in the list.
406 Therefore, the use of iterators in concurrent environment is not good idea. Use the iterator on the concurrent container
407 for debug purpose only.
409 typedef iterator_type<false> iterator;
410 /// Const forward iterator
412 For iterator's features and requirements see \ref iterator
414 typedef iterator_type<true> const_iterator;
416 /// Returns a forward iterator addressing the first element in a list
418 For empty list \code begin() == end() \endcode
422 iterator it( &m_Head );
423 ++it ; // skip dummy head
427 /// Returns an iterator that addresses the location succeeding the last element in a list
429 Do not use the value returned by <tt>end</tt> function to access any item.
431 The returned value can be used only to control reaching the end of the list.
432 For empty list \code begin() == end() \endcode
436 return iterator( &m_Tail );
439 /// Returns a forward const iterator addressing the first element in a list
441 const_iterator begin() const
443 return get_const_begin();
445 const_iterator cbegin() const
447 return get_const_begin();
451 /// Returns an const iterator that addresses the location succeeding the last element in a list
453 const_iterator end() const
455 return get_const_end();
457 const_iterator cend() const
459 return get_const_end();
465 const_iterator get_const_begin() const
467 const_iterator it( const_cast<node_type *>( &m_Head ));
468 ++it ; // skip dummy head
471 const_iterator get_const_end() const
473 return const_iterator( const_cast<node_type *>(&m_Tail) );
478 /// Default constructor initializes empty list
481 static_assert( (std::is_same< gc, typename node_type::gc >::value), "GC and node_type::gc must be the same type" );
482 m_Head.m_pNext.store( marked_node_ptr( &m_Tail ), memory_model::memory_order_relaxed );
485 /// Destroys the list object
489 assert( m_Head.m_pNext.load( memory_model::memory_order_relaxed ).ptr() == &m_Tail );
490 m_Head.m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
495 The function inserts \p val in the list if the list does not contain
496 an item with key equal to \p val.
498 Returns \p true if \p val is linked into the list, \p false otherwise.
500 bool insert( value_type& val )
502 return insert_at( &m_Head, val );
507 This function is intended for derived non-intrusive containers.
509 The function allows to split new item creating into two part:
510 - create item with key only
511 - insert new item into the list
512 - if inserting is success, calls \p f functor to initialize value-field of \p val.
514 The functor signature is:
516 void func( value_type& val );
518 where \p val is the item inserted.
519 While the functor \p f is called the item \p val is locked so
520 the functor has an exclusive access to the item.
521 The user-defined functor is called only if the inserting is success.
523 template <typename Func>
524 bool insert( value_type& val, Func f )
526 return insert_at( &m_Head, val, f );
531 The operation performs inserting or changing data with lock-free manner.
533 If the item \p val not found in the list, then \p val is inserted into the list
534 iff \p bAllowInsert is \p true.
535 Otherwise, the functor \p func is called with item found.
536 The functor signature is:
539 void operator()( bool bNew, value_type& item, value_type& val );
543 - \p bNew - \p true if the item has been inserted, \p false otherwise
544 - \p item - item of the list
545 - \p val - argument \p val passed into the \p update() function
546 If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
547 refer to the same thing.
549 The functor may change non-key fields of the \p item.
550 While the functor \p f is working the item \p item is locked,
551 so \p func has exclusive access to the item.
553 Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successfull,
554 \p second is \p true if new item has been added or \p false if the item with \p key
555 already is in the list.
557 The function makes RCU lock internally.
559 template <typename Func>
560 std::pair<bool, bool> update( value_type& val, Func func, bool bAllowInsert = true )
562 return update_at( &m_Head, val, func, bAllowInsert );
565 // Deprecated, use update()
566 template <typename Func>
567 std::pair<bool, bool> ensure( value_type& val, Func func )
569 return update( val, func, true );
573 /// Unlinks the item \p val from the list
575 The function searches the item \p val in the list and unlink it from the list
576 if it is found and it is equal to \p val.
578 Difference between \ref erase and \p unlink functions: \p erase finds <i>a key</i>
579 and deletes the item found. \p unlink finds an item by key and deletes it
580 only if \p val is an item of that list, i.e. the pointer to item found
581 is equal to <tt> &val </tt>.
583 The function returns \p true if success and \p false otherwise.
585 bool unlink( value_type& val )
587 return unlink_at( &m_Head, val );
590 /// Deletes the item from the list
591 /** \anchor cds_intrusive_LazyList_hp_erase_val
592 The function searches an item with key equal to \p key in the list,
593 unlinks it from the list, and returns \p true.
594 If the item with the key equal to \p key is not found the function return \p false.
596 template <typename Q>
597 bool erase( Q const& key )
599 return erase_at( &m_Head, key, key_comparator() );
602 /// Deletes the item from the list using \p pred predicate for searching
604 The function is an analog of \ref cds_intrusive_LazyList_hp_erase_val "erase(Q const&)"
605 but \p pred is used for key comparing.
606 \p Less functor has the interface like \p std::less.
607 \p pred must imply the same element order as the comparator used for building the list.
609 template <typename Q, typename Less>
610 bool erase_with( Q const& key, Less pred )
613 return erase_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>() );
616 /// Deletes the item from the list
617 /** \anchor cds_intrusive_LazyList_hp_erase_func
618 The function searches an item with key equal to \p key in the list,
619 call \p func functor with item found, unlinks it from the list, and returns \p true.
620 The \p Func interface is
623 void operator()( value_type const& item );
627 If \p key is not found the function return \p false.
629 template <typename Q, typename Func>
630 bool erase( const Q& key, Func func )
632 return erase_at( &m_Head, key, key_comparator(), func );
635 /// Deletes the item from the list using \p pred predicate for searching
637 The function is an analog of \ref cds_intrusive_LazyList_hp_erase_func "erase(Q const&, Func)"
638 but \p pred is used for key comparing.
639 \p Less functor has the interface like \p std::less.
640 \p pred must imply the same element order as the comparator used for building the list.
642 template <typename Q, typename Less, typename Func>
643 bool erase_with( const Q& key, Less pred, Func func )
646 return erase_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), func );
649 /// Extracts the item from the list with specified \p key
650 /** \anchor cds_intrusive_LazyList_hp_extract
651 The function searches an item with key equal to \p key,
652 unlinks it from the list, and returns it as \p guarded_ptr.
653 If \p key is not found the function returns an empty guarded pointer.
655 Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
657 The \ref disposer specified in \p Traits class template parameter is called automatically
658 by garbage collector \p GC specified in class' template parameters when returned \p guarded_ptr object
659 will be destroyed or released.
660 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
664 typedef cds::intrusive::LazyList< cds::gc::HP, foo, my_traits > ord_list;
668 ord_list::guarded_ptr gp( theList.extract( 5 ));
672 // Destructor of gp releases internal HP guard
676 template <typename Q>
677 guarded_ptr extract( Q const& key )
680 extract_at( &m_Head, gp.guard(), key, key_comparator() );
684 /// Extracts the item from the list with comparing functor \p pred
686 The function is an analog of \ref cds_intrusive_LazyList_hp_extract "extract(Q const&)"
687 but \p pred predicate is used for key comparing.
689 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
691 \p pred must imply the same element order as the comparator used for building the list.
693 template <typename Q, typename Less>
694 guarded_ptr extract_with( Q const& key, Less pred )
698 extract_at( &m_Head, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>() );
702 /// Finds the key \p key
703 /** \anchor cds_intrusive_LazyList_hp_find
704 The function searches the item with key equal to \p key and calls the functor \p f for item found.
705 The interface of \p Func functor is:
708 void operator()( value_type& item, Q& key );
711 where \p item is the item found, \p key is the <tt>find</tt> function argument.
713 The functor may change non-key fields of \p item.
714 While the functor \p f is calling the item \p item is locked.
716 The function returns \p true if \p key is found, \p false otherwise.
718 template <typename Q, typename Func>
719 bool find( Q& key, Func f )
721 return find_at( &m_Head, key, key_comparator(), f );
724 template <typename Q, typename Func>
725 bool find( Q const& key, Func f )
727 return find_at( &m_Head, key, key_comparator(), f );
731 /// Finds the key \p key using \p pred predicate for searching
733 The function is an analog of \ref cds_intrusive_LazyList_hp_find "find(Q&, Func)"
734 but \p pred is used for key comparing.
735 \p Less functor has the interface like \p std::less.
736 \p pred must imply the same element order as the comparator used for building the list.
738 template <typename Q, typename Less, typename Func>
739 bool find_with( Q& key, Less pred, Func f )
742 return find_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), f );
745 template <typename Q, typename Less, typename Func>
746 bool find_with( Q const& key, Less pred, Func f )
749 return find_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), f );
753 /// Checks whether the list contains \p key
755 The function searches the item with key equal to \p key
756 and returns \p true if it is found, and \p false otherwise.
758 template <typename Q>
759 bool contains( Q const& key )
761 return find_at( &m_Head, key, key_comparator() );
764 // Deprecated, use contains()
765 template <typename Q>
766 bool find( Q const& key )
768 return contains( key );
772 /// Checks whether the map contains \p key using \p pred predicate for searching
774 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
775 \p Less functor has the interface like \p std::less.
776 \p Less must imply the same element order as the comparator used for building the list.
778 template <typename Q, typename Less>
779 bool contains( Q const& key, Less pred )
782 return find_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>() );
785 // Deprecated, use contains()
786 template <typename Q, typename Less>
787 bool find_with( Q const& key, Less pred )
789 return contains( key, pred );
793 /// Finds \p key and return the item found
794 /** \anchor cds_intrusive_LazyList_hp_get
795 The function searches the item with key equal to \p key
796 and returns an guarded pointer to it.
797 If \p key is not found the function returns an empty guarded pointer.
799 The \ref disposer specified in \p Traits class template parameter is called
800 by garbage collector \p GC automatically when returned \p guarded_ptr object
801 will be destroyed or released.
802 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
806 typedef cds::intrusive::LazyList< cds::gc::HP, foo, my_traits > ord_list;
810 ord_list::guarded_ptr gp(theList.get( 5 ));
815 // Destructor of guarded_ptr releases internal HP guard
819 Note the compare functor specified for class \p Traits template parameter
820 should accept a parameter of type \p Q that can be not the same as \p value_type.
822 template <typename Q>
823 guarded_ptr get( Q const& key )
826 get_at( &m_Head, gp.guard(), key, key_comparator() );
830 /// Finds \p key and return the item found
832 The function is an analog of \ref cds_intrusive_LazyList_hp_get "get( Q const&)"
833 but \p pred is used for comparing the keys.
835 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
837 \p pred must imply the same element order as the comparator used for building the list.
839 template <typename Q, typename Less>
840 guarded_ptr get_with( Q const& key, Less pred )
844 get_at( &m_Head, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>() );
851 typename gc::Guard guard;
854 h = m_Head.m_pNext.load( memory_model::memory_order_relaxed );
855 guard.assign( node_traits::to_value_ptr( h.ptr() ));
856 if ( m_Head.m_pNext.load(memory_model::memory_order_acquire) == h ) {
857 m_Head.m_Lock.lock();
860 unlink_node( &m_Head, h.ptr(), &m_Head );
863 m_Head.m_Lock.unlock();
865 retire_node( h.ptr() ) ; // free node
870 /// Checks if the list is empty
873 return m_Head.m_pNext.load( memory_model::memory_order_relaxed ).ptr() == &m_Tail;
876 /// Returns list's item count
878 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
879 this function always returns 0.
881 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
882 is empty. To check list emptyness use \p empty() method.
886 return m_ItemCounter.value();
891 // split-list support
892 bool insert_aux_node( node_type * pNode )
894 return insert_aux_node( &m_Head, pNode );
897 // split-list support
898 bool insert_aux_node( node_type * pHead, node_type * pNode )
900 assert( pNode != nullptr );
902 // Hack: convert node_type to value_type.
903 // In principle, auxiliary node cannot be reducible to value_type
904 // We assume that internal comparator can correctly distinguish aux and regular node.
905 return insert_at( pHead, *node_traits::to_value_ptr( pNode ) );
908 bool insert_at( node_type * pHead, value_type& val )
910 link_checker::is_empty( node_traits::to_node_ptr( val ) );
915 search( pHead, val, pos, key_comparator() );
917 auto_lock_position alp( pos );
918 if ( validate( pos.pPred, pos.pCur )) {
919 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
920 // failed: key already in list
924 link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
933 template <typename Func>
934 bool insert_at( node_type * pHead, value_type& val, Func f )
936 link_checker::is_empty( node_traits::to_node_ptr( val ) );
941 search( pHead, val, pos, key_comparator() );
943 auto_lock_position alp( pos );
944 if ( validate( pos.pPred, pos.pCur )) {
945 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
946 // failed: key already in list
950 link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
960 template <typename Func>
961 std::pair<bool, bool> update_at( node_type * pHead, value_type& val, Func func, bool bAllowInsert )
967 search( pHead, val, pos, key_comparator() );
969 auto_lock_position alp( pos );
970 if ( validate( pos.pPred, pos.pCur )) {
971 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
972 // key already in the list
974 func( false, *node_traits::to_value_ptr( *pos.pCur ) , val );
975 return std::make_pair( true, false );
980 return std::make_pair( false, false );
982 link_checker::is_empty( node_traits::to_node_ptr( val ) );
984 link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
985 func( true, val, val );
987 return std::make_pair( true, true );
994 bool unlink_at( node_type * pHead, value_type& val )
1000 search( pHead, val, pos, key_comparator() );
1004 auto_lock_position alp( pos );
1005 if ( validate( pos.pPred, pos.pCur ) ) {
1006 if ( pos.pCur != &m_Tail
1007 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0
1008 && node_traits::to_value_ptr( pos.pCur ) == &val )
1011 unlink_node( pos.pPred, pos.pCur, pHead );
1020 if ( nResult > 0 ) {
1021 retire_node( pos.pCur );
1030 template <typename Q, typename Compare, typename Func>
1031 bool erase_at( node_type * pHead, const Q& val, Compare cmp, Func f, position& pos )
1034 search( pHead, val, pos, cmp );
1038 auto_lock_position alp( pos );
1039 if ( validate( pos.pPred, pos.pCur )) {
1040 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
1042 unlink_node( pos.pPred, pos.pCur, pHead );
1043 f( *node_traits::to_value_ptr( *pos.pCur ) );
1053 if ( nResult > 0 ) {
1054 retire_node( pos.pCur );
1063 template <typename Q, typename Compare, typename Func>
1064 bool erase_at( node_type * pHead, const Q& val, Compare cmp, Func f )
1067 return erase_at( pHead, val, cmp, f, pos );
1070 template <typename Q, typename Compare>
1071 bool erase_at( node_type * pHead, const Q& val, Compare cmp )
1074 return erase_at( pHead, val, cmp, [](value_type const &){}, pos );
1077 template <typename Q, typename Compare>
1078 bool extract_at( node_type * pHead, typename guarded_ptr::native_guard& gp, const Q& val, Compare cmp )
1081 if ( erase_at( pHead, val, cmp, [](value_type const &){}, pos )) {
1082 gp.set( pos.guards.template get<value_type>(position::guard_current_item) );
1088 template <typename Q, typename Compare, typename Func>
1089 bool find_at( node_type * pHead, Q& val, Compare cmp, Func f )
1093 search( pHead, val, pos, cmp );
1094 if ( pos.pCur != &m_Tail ) {
1095 std::unique_lock< typename node_type::lock_type> al( pos.pCur->m_Lock );
1096 if ( !pos.pCur->is_marked()
1097 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 )
1099 f( *node_traits::to_value_ptr( *pos.pCur ), val );
1106 template <typename Q, typename Compare>
1107 bool find_at( node_type * pHead, Q const& val, Compare cmp )
1111 search( pHead, val, pos, cmp );
1112 return pos.pCur != &m_Tail
1113 && !pos.pCur->is_marked()
1114 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0;
1117 template <typename Q, typename Compare>
1118 bool get_at( node_type * pHead, typename guarded_ptr::native_guard& gp, Q const& val, Compare cmp )
1122 search( pHead, val, pos, cmp );
1123 if ( pos.pCur != &m_Tail
1124 && !pos.pCur->is_marked()
1125 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 )
1127 gp.set( pos.guards.template get<value_type>( position::guard_current_item ));
1137 template <typename Q, typename Compare>
1138 void search( node_type * pHead, const Q& key, position& pos, Compare cmp )
1140 const node_type * pTail = &m_Tail;
1142 marked_node_ptr pCur( pHead );
1143 marked_node_ptr pPrev( pHead );
1147 while ( pCur.ptr() != pTail )
1149 if ( pCur.ptr() != pHead ) {
1150 if ( cmp( *node_traits::to_value_ptr( *pCur.ptr() ), key ) >= 0 )
1154 pos.guards.copy( position::guard_prev_item, position::guard_current_item );
1158 pCur = pPrev->m_pNext.load(memory_model::memory_order_relaxed);
1159 pos.guards.assign( position::guard_current_item, node_traits::to_value_ptr( pCur.ptr() ));
1160 if ( pCur == pPrev->m_pNext.load(memory_model::memory_order_acquire) )
1164 assert( pCur.ptr() != nullptr );
1167 pos.pCur = pCur.ptr();
1168 pos.pPred = pPrev.ptr();
1171 static bool validate( node_type * pPred, node_type * pCur )
1173 return !pPred->is_marked()
1174 && !pCur->is_marked()
1175 && pPred->m_pNext.load(memory_model::memory_order_relaxed) == pCur;
1180 }} // namespace cds::intrusive
1182 #endif // CDSLIB_INTRUSIVE_IMPL_LAZY_LIST_H