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 typedef std::unique_lock< position > scoped_position_lock;
246 void link_node( node_type * pNode, node_type * pPred, node_type * pCur )
248 assert( pPred->m_pNext.load(memory_model::memory_order_relaxed).ptr() == pCur );
250 pNode->m_pNext.store( marked_node_ptr(pCur), memory_model::memory_order_release );
251 pPred->m_pNext.store( marked_node_ptr(pNode), memory_model::memory_order_release );
254 void unlink_node( node_type * pPred, node_type * pCur, node_type * pHead )
256 assert( pPred->m_pNext.load(memory_model::memory_order_relaxed).ptr() == pCur );
258 node_type * pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr();
259 //pCur->m_pNext.store( marked_node_ptr( pNext, 1), memory_model::memory_order_release) ; // logically deleting
260 pCur->m_pNext.store( marked_node_ptr( pHead, 1 ), memory_model::memory_order_release ) ; // logical removal + back-link for search
261 pPred->m_pNext.store( marked_node_ptr( pNext ), memory_model::memory_order_release); // physically deleting
262 //pCur->m_pNext.store( marked_node_ptr( pHead, 1 ), memory_model::memory_order_release ) ; // back-link for search
265 void retire_node( node_type * pNode )
267 assert( pNode != nullptr );
268 gc::template retire<clean_disposer>( node_traits::to_value_ptr( *pNode ) );
274 template <bool IsConst>
277 friend class LazyList;
280 value_type * m_pNode;
281 typename gc::Guard m_Guard;
285 assert( m_pNode != nullptr );
288 typename gc::Guard g;
289 node_type * pCur = node_traits::to_node_ptr( m_pNode );
290 if ( pCur->m_pNext.load( memory_model::memory_order_relaxed ).ptr() != nullptr ) { // if pCur is not tail node
293 pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr();
294 g.assign( node_traits::to_value_ptr( pNext ));
295 } while ( pNext != pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr() );
297 m_pNode = m_Guard.assign( g.template get<value_type>() );
304 if ( m_pNode != nullptr ) {
305 typename gc::Guard g;
306 node_type * pNode = node_traits::to_node_ptr( m_pNode );
308 // Dummy tail node could not be marked
309 while ( pNode->is_marked() ) {
310 node_type * p = pNode->m_pNext.load(memory_model::memory_order_relaxed).ptr();
311 g.assign( node_traits::to_value_ptr( p ));
312 if ( p == pNode->m_pNext.load(memory_model::memory_order_relaxed).ptr() )
315 if ( pNode != node_traits::to_node_ptr( m_pNode ) )
316 m_pNode = m_Guard.assign( g.template get<value_type>() );
320 iterator_type( node_type * pNode )
322 m_pNode = m_Guard.assign( node_traits::to_value_ptr( pNode ));
327 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
328 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
334 iterator_type( iterator_type const& src )
337 m_pNode = m_Guard.assign( src.m_pNode );
343 value_ptr operator ->() const
348 value_ref operator *() const
350 assert( m_pNode != nullptr );
355 iterator_type& operator ++()
362 iterator_type& operator = (iterator_type const& src)
364 m_pNode = src.m_pNode;
365 m_Guard.assign( m_pNode );
370 bool operator ==(iterator_type<C> const& i ) const
372 return m_pNode == i.m_pNode;
375 bool operator !=(iterator_type<C> const& i ) const
377 return m_pNode != i.m_pNode;
385 The forward iterator for lazy list has some features:
386 - it has no post-increment operator
387 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
388 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
389 may be thrown if a limit of guard count per thread is exceeded.
390 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
391 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
392 deleting operations it is no guarantee that you iterate all item in the list.
394 Therefore, the use of iterators in concurrent environment is not good idea. Use the iterator on the concurrent container
395 for debug purpose only.
397 typedef iterator_type<false> iterator;
398 /// Const forward iterator
400 For iterator's features and requirements see \ref iterator
402 typedef iterator_type<true> const_iterator;
404 /// Returns a forward iterator addressing the first element in a list
406 For empty list \code begin() == end() \endcode
410 iterator it( &m_Head );
411 ++it ; // skip dummy head
415 /// Returns an iterator that addresses the location succeeding the last element in a list
417 Do not use the value returned by <tt>end</tt> function to access any item.
419 The returned value can be used only to control reaching the end of the list.
420 For empty list \code begin() == end() \endcode
424 return iterator( &m_Tail );
427 /// Returns a forward const iterator addressing the first element in a list
429 const_iterator begin() const
431 return get_const_begin();
433 const_iterator cbegin() const
435 return get_const_begin();
439 /// Returns an const iterator that addresses the location succeeding the last element in a list
441 const_iterator end() const
443 return get_const_end();
445 const_iterator cend() const
447 return get_const_end();
453 const_iterator get_const_begin() const
455 const_iterator it( const_cast<node_type *>( &m_Head ));
456 ++it ; // skip dummy head
459 const_iterator get_const_end() const
461 return const_iterator( const_cast<node_type *>(&m_Tail) );
466 /// Default constructor initializes empty list
469 static_assert( (std::is_same< gc, typename node_type::gc >::value), "GC and node_type::gc must be the same type" );
470 m_Head.m_pNext.store( marked_node_ptr( &m_Tail ), memory_model::memory_order_relaxed );
473 /// Destroys the list object
477 assert( m_Head.m_pNext.load( memory_model::memory_order_relaxed ).ptr() == &m_Tail );
478 m_Head.m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
483 The function inserts \p val in the list if the list does not contain
484 an item with key equal to \p val.
486 Returns \p true if \p val is linked into the list, \p false otherwise.
488 bool insert( value_type& val )
490 return insert_at( &m_Head, val );
495 This function is intended for derived non-intrusive containers.
497 The function allows to split new item creating into two part:
498 - create item with key only
499 - insert new item into the list
500 - if inserting is success, calls \p f functor to initialize value-field of \p val.
502 The functor signature is:
504 void func( value_type& val );
506 where \p val is the item inserted.
507 While the functor \p f is called the item \p val is locked so
508 the functor has an exclusive access to the item.
509 The user-defined functor is called only if the inserting is success.
511 template <typename Func>
512 bool insert( value_type& val, Func f )
514 return insert_at( &m_Head, val, f );
519 The operation performs inserting or changing data with lock-free manner.
521 If the item \p val not found in the list, then \p val is inserted into the list
522 iff \p bAllowInsert is \p true.
523 Otherwise, the functor \p func is called with item found.
524 The functor signature is:
527 void operator()( bool bNew, value_type& item, value_type& val );
531 - \p bNew - \p true if the item has been inserted, \p false otherwise
532 - \p item - item of the list
533 - \p val - argument \p val passed into the \p update() function
534 If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
535 refer to the same thing.
537 The functor may change non-key fields of the \p item.
538 While the functor \p f is working the item \p item is locked,
539 so \p func has exclusive access to the item.
541 Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successfull,
542 \p second is \p true if new item has been added or \p false if the item with \p key
543 already is in the list.
545 The function makes RCU lock internally.
547 template <typename Func>
548 std::pair<bool, bool> update( value_type& val, Func func, bool bAllowInsert = true )
550 return update_at( &m_Head, val, func, bAllowInsert );
553 template <typename Func>
554 CDS_DEPRECATED("ensure() is deprecated, use update()")
555 std::pair<bool, bool> ensure( value_type& val, Func func )
557 return update( val, func, true );
561 /// Unlinks the item \p val from the list
563 The function searches the item \p val in the list and unlink it from the list
564 if it is found and it is equal to \p val.
566 Difference between \ref erase and \p unlink functions: \p erase finds <i>a key</i>
567 and deletes the item found. \p unlink finds an item by key and deletes it
568 only if \p val is an item of that list, i.e. the pointer to item found
569 is equal to <tt> &val </tt>.
571 The function returns \p true if success and \p false otherwise.
573 bool unlink( value_type& val )
575 return unlink_at( &m_Head, val );
578 /// Deletes the item from the list
579 /** \anchor cds_intrusive_LazyList_hp_erase_val
580 The function searches an item with key equal to \p key in the list,
581 unlinks it from the list, and returns \p true.
582 If the item with the key equal to \p key is not found the function return \p false.
584 template <typename Q>
585 bool erase( Q const& key )
587 return erase_at( &m_Head, key, key_comparator() );
590 /// Deletes the item from the list using \p pred predicate for searching
592 The function is an analog of \ref cds_intrusive_LazyList_hp_erase_val "erase(Q const&)"
593 but \p pred is used for key comparing.
594 \p Less functor has the interface like \p std::less.
595 \p pred must imply the same element order as the comparator used for building the list.
597 template <typename Q, typename Less>
598 bool erase_with( Q const& key, Less pred )
601 return erase_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>() );
604 /// Deletes the item from the list
605 /** \anchor cds_intrusive_LazyList_hp_erase_func
606 The function searches an item with key equal to \p key in the list,
607 call \p func functor with item found, unlinks it from the list, and returns \p true.
608 The \p Func interface is
611 void operator()( value_type const& item );
615 If \p key is not found the function return \p false.
617 template <typename Q, typename Func>
618 bool erase( const Q& key, Func func )
620 return erase_at( &m_Head, key, key_comparator(), func );
623 /// Deletes the item from the list using \p pred predicate for searching
625 The function is an analog of \ref cds_intrusive_LazyList_hp_erase_func "erase(Q const&, Func)"
626 but \p pred is used for key comparing.
627 \p Less functor has the interface like \p std::less.
628 \p pred must imply the same element order as the comparator used for building the list.
630 template <typename Q, typename Less, typename Func>
631 bool erase_with( const Q& key, Less pred, Func func )
634 return erase_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), func );
637 /// Extracts the item from the list with specified \p key
638 /** \anchor cds_intrusive_LazyList_hp_extract
639 The function searches an item with key equal to \p key,
640 unlinks it from the list, and returns it as \p guarded_ptr.
641 If \p key is not found the function returns an empty guarded pointer.
643 Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
645 The \ref disposer specified in \p Traits class template parameter is called automatically
646 by garbage collector \p GC specified in class' template parameters when returned \p guarded_ptr object
647 will be destroyed or released.
648 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
652 typedef cds::intrusive::LazyList< cds::gc::HP, foo, my_traits > ord_list;
656 ord_list::guarded_ptr gp( theList.extract( 5 ));
660 // Destructor of gp releases internal HP guard
664 template <typename Q>
665 guarded_ptr extract( Q const& key )
668 extract_at( &m_Head, gp.guard(), key, key_comparator() );
672 /// Extracts the item from the list with comparing functor \p pred
674 The function is an analog of \ref cds_intrusive_LazyList_hp_extract "extract(Q const&)"
675 but \p pred predicate is used for key comparing.
677 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
679 \p pred must imply the same element order as the comparator used for building the list.
681 template <typename Q, typename Less>
682 guarded_ptr extract_with( Q const& key, Less pred )
686 extract_at( &m_Head, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>() );
690 /// Finds the key \p key
691 /** \anchor cds_intrusive_LazyList_hp_find
692 The function searches the item with key equal to \p key and calls the functor \p f for item found.
693 The interface of \p Func functor is:
696 void operator()( value_type& item, Q& key );
699 where \p item is the item found, \p key is the <tt>find</tt> function argument.
701 The functor may change non-key fields of \p item.
702 While the functor \p f is calling the item \p item is locked.
704 The function returns \p true if \p key is found, \p false otherwise.
706 template <typename Q, typename Func>
707 bool find( Q& key, Func f )
709 return find_at( &m_Head, key, key_comparator(), f );
712 template <typename Q, typename Func>
713 bool find( Q const& key, Func f )
715 return find_at( &m_Head, key, key_comparator(), f );
719 /// Finds the key \p key using \p pred predicate for searching
721 The function is an analog of \ref cds_intrusive_LazyList_hp_find "find(Q&, Func)"
722 but \p pred is used for key comparing.
723 \p Less functor has the interface like \p std::less.
724 \p pred must imply the same element order as the comparator used for building the list.
726 template <typename Q, typename Less, typename Func>
727 bool find_with( Q& key, Less pred, Func f )
730 return find_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), f );
733 template <typename Q, typename Less, typename Func>
734 bool find_with( Q const& key, Less pred, Func f )
737 return find_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), f );
741 /// Checks whether the list contains \p key
743 The function searches the item with key equal to \p key
744 and returns \p true if it is found, and \p false otherwise.
746 template <typename Q>
747 bool contains( Q const& key )
749 return find_at( &m_Head, key, key_comparator() );
752 template <typename Q>
753 CDS_DEPRECATED("deprecated, use contains()")
754 bool find( Q const& key )
756 return contains( key );
760 /// Checks whether the map contains \p key using \p pred predicate for searching
762 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
763 \p Less functor has the interface like \p std::less.
764 \p Less must imply the same element order as the comparator used for building the list.
766 template <typename Q, typename Less>
767 bool contains( Q const& key, Less pred )
770 return find_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>() );
773 template <typename Q, typename Less>
774 CDS_DEPRECATED("deprecated, use contains()")
775 bool find_with( Q const& key, Less pred )
777 return contains( key, pred );
781 /// Finds \p key and return the item found
782 /** \anchor cds_intrusive_LazyList_hp_get
783 The function searches the item with key equal to \p key
784 and returns an guarded pointer to it.
785 If \p key is not found the function returns an empty guarded pointer.
787 The \ref disposer specified in \p Traits class template parameter is called
788 by garbage collector \p GC automatically when returned \p guarded_ptr object
789 will be destroyed or released.
790 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
794 typedef cds::intrusive::LazyList< cds::gc::HP, foo, my_traits > ord_list;
798 ord_list::guarded_ptr gp(theList.get( 5 ));
803 // Destructor of guarded_ptr releases internal HP guard
807 Note the compare functor specified for class \p Traits template parameter
808 should accept a parameter of type \p Q that can be not the same as \p value_type.
810 template <typename Q>
811 guarded_ptr get( Q const& key )
814 get_at( &m_Head, gp.guard(), key, key_comparator() );
818 /// Finds \p key and return the item found
820 The function is an analog of \ref cds_intrusive_LazyList_hp_get "get( Q const&)"
821 but \p pred is used for comparing the keys.
823 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
825 \p pred must imply the same element order as the comparator used for building the list.
827 template <typename Q, typename Less>
828 guarded_ptr get_with( Q const& key, Less pred )
832 get_at( &m_Head, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>() );
839 typename gc::Guard guard;
842 h = m_Head.m_pNext.load( memory_model::memory_order_relaxed );
843 guard.assign( node_traits::to_value_ptr( h.ptr() ));
844 if ( m_Head.m_pNext.load(memory_model::memory_order_acquire) == h ) {
845 m_Head.m_Lock.lock();
848 unlink_node( &m_Head, h.ptr(), &m_Head );
851 m_Head.m_Lock.unlock();
853 retire_node( h.ptr() ) ; // free node
858 /// Checks if the list is empty
861 return m_Head.m_pNext.load( memory_model::memory_order_relaxed ).ptr() == &m_Tail;
864 /// Returns list's item count
866 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
867 this function always returns 0.
869 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
870 is empty. To check list emptyness use \p empty() method.
874 return m_ItemCounter.value();
879 // split-list support
880 bool insert_aux_node( node_type * pNode )
882 return insert_aux_node( &m_Head, pNode );
885 // split-list support
886 bool insert_aux_node( node_type * pHead, node_type * pNode )
888 assert( pNode != nullptr );
890 // Hack: convert node_type to value_type.
891 // In principle, auxiliary node cannot be reducible to value_type
892 // We assume that internal comparator can correctly distinguish aux and regular node.
893 return insert_at( pHead, *node_traits::to_value_ptr( pNode ) );
896 bool insert_at( node_type * pHead, value_type& val )
898 link_checker::is_empty( node_traits::to_node_ptr( val ) );
903 search( pHead, val, pos, key_comparator() );
905 scoped_position_lock alp( pos );
906 if ( validate( pos.pPred, pos.pCur )) {
907 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
908 // failed: key already in list
912 link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
921 template <typename Func>
922 bool insert_at( node_type * pHead, value_type& val, Func f )
924 link_checker::is_empty( node_traits::to_node_ptr( val ) );
929 search( pHead, val, pos, key_comparator() );
931 scoped_position_lock alp( pos );
932 if ( validate( pos.pPred, pos.pCur )) {
933 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
934 // failed: key already in list
938 link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
948 template <typename Func>
949 std::pair<bool, bool> update_at( node_type * pHead, value_type& val, Func func, bool bAllowInsert )
955 search( pHead, val, pos, key_comparator() );
957 scoped_position_lock alp( pos );
958 if ( validate( pos.pPred, pos.pCur )) {
959 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
960 // key already in the list
962 func( false, *node_traits::to_value_ptr( *pos.pCur ) , val );
963 return std::make_pair( true, false );
968 return std::make_pair( false, false );
970 link_checker::is_empty( node_traits::to_node_ptr( val ) );
972 link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
973 func( true, val, val );
975 return std::make_pair( true, true );
982 bool unlink_at( node_type * pHead, value_type& val )
988 search( pHead, val, pos, key_comparator() );
992 scoped_position_lock alp( pos );
993 if ( validate( pos.pPred, pos.pCur ) ) {
994 if ( pos.pCur != &m_Tail
995 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0
996 && node_traits::to_value_ptr( pos.pCur ) == &val )
999 unlink_node( pos.pPred, pos.pCur, pHead );
1008 if ( nResult > 0 ) {
1009 retire_node( pos.pCur );
1018 template <typename Q, typename Compare, typename Func>
1019 bool erase_at( node_type * pHead, const Q& val, Compare cmp, Func f, position& pos )
1022 search( pHead, val, pos, cmp );
1026 scoped_position_lock alp( pos );
1027 if ( validate( pos.pPred, pos.pCur )) {
1028 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
1030 unlink_node( pos.pPred, pos.pCur, pHead );
1031 f( *node_traits::to_value_ptr( *pos.pCur ) );
1041 if ( nResult > 0 ) {
1042 retire_node( pos.pCur );
1051 template <typename Q, typename Compare, typename Func>
1052 bool erase_at( node_type * pHead, const Q& val, Compare cmp, Func f )
1055 return erase_at( pHead, val, cmp, f, pos );
1058 template <typename Q, typename Compare>
1059 bool erase_at( node_type * pHead, const Q& val, Compare cmp )
1062 return erase_at( pHead, val, cmp, [](value_type const &){}, pos );
1065 template <typename Q, typename Compare>
1066 bool extract_at( node_type * pHead, typename guarded_ptr::native_guard& gp, const Q& val, Compare cmp )
1069 if ( erase_at( pHead, val, cmp, [](value_type const &){}, pos )) {
1070 gp.set( pos.guards.template get<value_type>(position::guard_current_item) );
1076 template <typename Q, typename Compare, typename Func>
1077 bool find_at( node_type * pHead, Q& val, Compare cmp, Func f )
1081 search( pHead, val, pos, cmp );
1082 if ( pos.pCur != &m_Tail ) {
1083 std::unique_lock< typename node_type::lock_type> al( pos.pCur->m_Lock );
1084 if ( !pos.pCur->is_marked()
1085 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 )
1087 f( *node_traits::to_value_ptr( *pos.pCur ), val );
1094 template <typename Q, typename Compare>
1095 bool find_at( node_type * pHead, Q const& val, Compare cmp )
1099 search( pHead, val, pos, cmp );
1100 return pos.pCur != &m_Tail
1101 && !pos.pCur->is_marked()
1102 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0;
1105 template <typename Q, typename Compare>
1106 bool get_at( node_type * pHead, typename guarded_ptr::native_guard& gp, Q const& val, Compare cmp )
1110 search( pHead, val, pos, cmp );
1111 if ( pos.pCur != &m_Tail
1112 && !pos.pCur->is_marked()
1113 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 )
1115 gp.set( pos.guards.template get<value_type>( position::guard_current_item ));
1125 template <typename Q, typename Compare>
1126 void search( node_type * pHead, const Q& key, position& pos, Compare cmp )
1128 const node_type * pTail = &m_Tail;
1130 marked_node_ptr pCur( pHead );
1131 marked_node_ptr pPrev( pHead );
1135 while ( pCur.ptr() != pTail )
1137 if ( pCur.ptr() != pHead ) {
1138 if ( cmp( *node_traits::to_value_ptr( *pCur.ptr() ), key ) >= 0 )
1142 pos.guards.copy( position::guard_prev_item, position::guard_current_item );
1146 pCur = pPrev->m_pNext.load(memory_model::memory_order_relaxed);
1147 pos.guards.assign( position::guard_current_item, node_traits::to_value_ptr( pCur.ptr() ));
1148 if ( pCur == pPrev->m_pNext.load(memory_model::memory_order_acquire) )
1152 assert( pCur.ptr() != nullptr );
1155 pos.pCur = pCur.ptr();
1156 pos.pPred = pPrev.ptr();
1159 static bool validate( node_type * pPred, node_type * pCur )
1161 return !pPred->is_marked()
1162 && !pCur->is_marked()
1163 && pPred->m_pNext.load(memory_model::memory_order_relaxed) == pCur;
1168 }} // namespace cds::intrusive
1170 #endif // CDSLIB_INTRUSIVE_IMPL_LAZY_LIST_H