2 This file is a part of libcds - Concurrent Data Structures library
4 (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
6 Source code repo: http://github.com/khizmax/libcds/
7 Download: http://sourceforge.net/projects/libcds/files/
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31 #ifndef CDSLIB_INTRUSIVE_IMPL_LAZY_LIST_H
32 #define CDSLIB_INTRUSIVE_IMPL_LAZY_LIST_H
34 #include <mutex> // unique_lock
35 #include <cds/intrusive/details/lazy_list_base.h>
37 namespace cds { namespace intrusive {
39 /// Lazy ordered single-linked list
40 /** @ingroup cds_intrusive_list
41 \anchor cds_intrusive_LazyList_hp
43 Usually, ordered single-linked list is used as a building block for the hash table implementation.
44 The complexity of searching is <tt>O(N)</tt>.
47 - [2005] Steve Heller, Maurice Herlihy, Victor Luchangco, Mark Moir, William N. Scherer III, and Nir Shavit
48 "A Lazy Concurrent List-Based Set Algorithm"
50 The lazy list is based on an optimistic locking scheme for inserts and removes,
51 eliminating the need to use the equivalent of an atomically markable
52 reference. It also has a novel wait-free membership \p find operation
53 that does not need to perform cleanup operations and is more efficient.
56 - \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).
57 - \p T - type to be stored in the list. The type must be based on lazy_list::node (for lazy_list::base_hook)
58 or it must have a member of type lazy_list::node (for lazy_list::member_hook).
59 - \p Traits - type traits. See lazy_list::traits for explanation.
60 It is possible to declare option-based list with cds::intrusive::lazy_list::make_traits metafunction istead of \p Traits template
61 argument. For example, the following traits-based declaration of \p gc::HP lazy list
63 #include <cds/intrusive/lazy_list_hp.h>
64 // Declare item stored in your list
65 struct item: public cds::intrusive::lazy_list::node< cds::gc::HP >
68 // Declare comparator for the item
69 struct my_compare { ... }
72 struct my_traits: public cds::intrusive::lazy_list::traits
74 typedef cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::HP > > hook;
75 typedef my_compare compare;
78 // Declare traits-based list
79 typedef cds::intrusive::LazyList< cds::gc::HP, item, my_traits > traits_based_list;
81 is equivalent for the following option-based list
83 #include <cds/intrusive/lazy_list_hp.h>
85 // item struct and my_compare are the same
87 // Declare option-based list
88 typedef cds::intrusive::LazyList< cds::gc::HP, item,
89 typename cds::intrusive::lazy_list::make_traits<
90 cds::intrusive::opt::hook< cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::HP > > > // hook option
91 ,cds::intrusive::opt::compare< my_compare > // item comparator option
97 There are different specializations of this template for each garbage collecting schema used.
98 You should select GC needed and include appropriate .h-file:
99 - for gc::HP: \code #include <cds/intrusive/lazy_list_hp.h> \endcode
100 - for gc::DHP: \code #include <cds/intrusive/lazy_list_dhp.h> \endcode
101 - for gc::nogc: \code #include <cds/intrusive/lazy_list_nogc.h> \endcode
102 - for \ref cds_urcu_type "RCU" - see \ref cds_intrusive_LazyList_rcu "LazyList RCU specialization"
104 Then, you should incorporate lazy_list::node into your struct \p T and provide
105 appropriate \p lazy_list::traits::hook in your \p Traits template parameters. Usually, for \p Traits
106 a struct based on \p lazy_list::traits should be defined.
108 Example for gc::DHP and base hook:
110 // Include GC-related lazy list specialization
111 #include <cds/intrusive/lazy_list_dhp.h>
113 // Data stored in lazy list
114 struct my_data: public cds::intrusive::lazy_list::node< cds::gc::DHP >
123 // my_data comparing functor
125 int operator()( const my_data& d1, const my_data& d2 )
127 return d1.strKey.compare( d2.strKey );
130 int operator()( const my_data& d, const std::string& s )
132 return d.strKey.compare(s);
135 int operator()( const std::string& s, const my_data& d )
137 return s.compare( d.strKey );
142 struct my_traits: public cds::intrusive::lazy_list::traits
144 typedef cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::DHP > > hook;
145 typedef my_data_cmp compare;
149 typedef cds::intrusive::LazyList< cds::gc::DHP, my_data, my_traits > traits_based_list;
152 Equivalent option-based code:
154 // GC-related specialization
155 #include <cds/intrusive/lazy_list_dhp.h>
164 // Declare option-based list
165 typedef cds::intrusive::LazyList< cds::gc::DHP
167 , typename cds::intrusive::lazy_list::make_traits<
168 cds::intrusive::opt::hook< cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::DHP > > >
169 ,cds::intrusive::opt::compare< my_data_cmp >
178 #ifdef CDS_DOXYGEN_INVOKED
179 ,class Traits = lazy_list::traits
187 typedef GC gc; ///< Garbage collector
188 typedef T value_type; ///< type of value stored in the list
189 typedef Traits traits; ///< Traits template parameter
191 typedef typename traits::hook hook; ///< hook type
192 typedef typename hook::node_type node_type; ///< node type
194 # ifdef CDS_DOXYGEN_INVOKED
195 typedef implementation_defined key_comparator; ///< key comparison functor based on opt::compare and opt::less option setter.
197 typedef typename opt::details::make_comparator< value_type, traits >::type key_comparator;
200 typedef typename traits::disposer disposer; ///< disposer
201 typedef typename get_node_traits< value_type, node_type, hook>::type node_traits; ///< node traits
202 typedef typename lazy_list::get_link_checker< node_type, traits::link_checker >::type link_checker; ///< link checker
204 typedef typename traits::back_off back_off; ///< back-off strategy
205 typedef typename traits::item_counter item_counter; ///< Item counting policy used
206 typedef typename traits::memory_model memory_model; ///< C++ memory ordering (see \p lazy_list::traits::memory_model)
208 typedef typename gc::template guarded_ptr< value_type > guarded_ptr; ///< Guarded pointer
210 static CDS_CONSTEXPR const size_t c_nHazardPtrCount = 4; ///< Count of hazard pointer required for the algorithm
213 // Rebind traits (split-list support)
214 template <typename... Options>
215 struct rebind_traits {
219 , typename cds::opt::make_options< traits, Options...>::type
225 typedef typename node_type::marked_ptr marked_node_ptr; ///< Node marked pointer
226 typedef node_type * auxiliary_head; ///< Auxiliary head type (for split-list support)
233 item_counter m_ItemCounter;
236 struct clean_disposer {
237 void operator()( value_type * p )
239 lazy_list::node_cleaner<gc, node_type, memory_model>()( node_traits::to_node_ptr( p ));
244 /// Position pointer for item search
246 node_type * pPred; ///< Previous node
247 node_type * pCur; ///< Current node
249 typename gc::template GuardArray<2> guards; ///< Guards array
256 /// Locks nodes \p pPred and \p pCur
259 pPred->m_Lock.lock();
263 /// Unlocks nodes \p pPred and \p pCur
266 pCur->m_Lock.unlock();
267 pPred->m_Lock.unlock();
271 typedef std::unique_lock< position > scoped_position_lock;
276 void link_node( node_type * pNode, node_type * pPred, node_type * pCur )
278 assert( pPred->m_pNext.load(memory_model::memory_order_relaxed).ptr() == pCur );
279 link_checker::is_empty( pNode );
281 pNode->m_pNext.store( marked_node_ptr(pCur), memory_model::memory_order_release );
282 pPred->m_pNext.store( marked_node_ptr(pNode), memory_model::memory_order_release );
285 void unlink_node( node_type * pPred, node_type * pCur, node_type * pHead )
287 assert( pPred->m_pNext.load(memory_model::memory_order_relaxed).ptr() == pCur );
289 node_type * pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr();
290 pCur->m_pNext.store( marked_node_ptr( pHead, 1 ), memory_model::memory_order_release ); // logical removal + back-link for search
291 pPred->m_pNext.store( marked_node_ptr( pNext ), memory_model::memory_order_release); // physically deleting
294 void retire_node( node_type * pNode )
296 assert( pNode != nullptr );
297 gc::template retire<clean_disposer>( node_traits::to_value_ptr( *pNode ));
303 template <bool IsConst>
306 friend class LazyList;
309 value_type * m_pNode;
310 typename gc::Guard m_Guard;
314 assert( m_pNode != nullptr );
317 typename gc::Guard g;
318 node_type * pCur = node_traits::to_node_ptr( m_pNode );
319 if ( pCur->m_pNext.load( memory_model::memory_order_relaxed ).ptr() != nullptr ) { // if pCur is not tail node
322 pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr();
323 g.assign( node_traits::to_value_ptr( pNext ));
324 } while ( pNext != pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr());
326 m_pNode = m_Guard.assign( g.template get<value_type>());
333 if ( m_pNode != nullptr ) {
334 typename gc::Guard g;
335 node_type * pNode = node_traits::to_node_ptr( m_pNode );
337 // Dummy tail node could not be marked
338 while ( pNode->is_marked()) {
339 node_type * p = pNode->m_pNext.load(memory_model::memory_order_relaxed).ptr();
340 g.assign( node_traits::to_value_ptr( p ));
341 if ( p == pNode->m_pNext.load(memory_model::memory_order_relaxed).ptr())
344 if ( pNode != node_traits::to_node_ptr( m_pNode ))
345 m_pNode = m_Guard.assign( g.template get<value_type>());
349 iterator_type( node_type * pNode )
351 m_pNode = m_Guard.assign( node_traits::to_value_ptr( pNode ));
356 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
357 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
363 iterator_type( iterator_type const& src )
366 m_pNode = m_Guard.assign( src.m_pNode );
372 value_ptr operator ->() const
377 value_ref operator *() const
379 assert( m_pNode != nullptr );
384 iterator_type& operator ++()
391 iterator_type& operator = (iterator_type const& src)
393 m_pNode = src.m_pNode;
394 m_Guard.assign( m_pNode );
399 bool operator ==(iterator_type<C> const& i ) const
401 return m_pNode == i.m_pNode;
404 bool operator !=(iterator_type<C> const& i ) const
406 return m_pNode != i.m_pNode;
412 ///@name Forward iterators (only for debugging purpose)
416 The forward iterator for lazy list has some features:
417 - it has no post-increment operator
418 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
419 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
420 may be thrown if a limit of guard count per thread is exceeded.
421 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
422 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
423 deleting operations it is no guarantee that you iterate all item in the list.
424 Moreover, a crash is possible when you try to iterate the next element that has been deleted by concurrent thread.
426 @warning Use this iterator on the concurrent container for debugging purpose only.
428 typedef iterator_type<false> iterator;
429 /// Const forward iterator
431 For iterator's features and requirements see \ref iterator
433 typedef iterator_type<true> const_iterator;
435 /// Returns a forward iterator addressing the first element in a list
437 For empty list \code begin() == end() \endcode
441 iterator it( &m_Head );
442 ++it ; // skip dummy head
446 /// Returns an iterator that addresses the location succeeding the last element in a list
448 Do not use the value returned by <tt>end</tt> function to access any item.
450 The returned value can be used only to control reaching the end of the list.
451 For empty list \code begin() == end() \endcode
455 return iterator( &m_Tail );
458 /// Returns a forward const iterator addressing the first element in a list
459 const_iterator begin() const
461 return get_const_begin();
464 /// Returns a forward const iterator addressing the first element in a list
465 const_iterator cbegin() const
467 return get_const_begin();
470 /// Returns an const iterator that addresses the location succeeding the last element in a list
471 const_iterator end() const
473 return get_const_end();
476 /// Returns an const iterator that addresses the location succeeding the last element in a list
477 const_iterator cend() const
479 return get_const_end();
485 const_iterator get_const_begin() const
487 const_iterator it( const_cast<node_type *>( &m_Head ));
488 ++it ; // skip dummy head
491 const_iterator get_const_end() const
493 return const_iterator( const_cast<node_type *>(&m_Tail));
498 /// Default constructor initializes empty list
501 static_assert( (std::is_same< gc, typename node_type::gc >::value), "GC and node_type::gc must be the same type" );
502 m_Head.m_pNext.store( marked_node_ptr( &m_Tail ), memory_model::memory_order_relaxed );
505 /// Destroys the list object
509 assert( m_Head.m_pNext.load( memory_model::memory_order_relaxed ).ptr() == &m_Tail );
510 m_Head.m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
515 The function inserts \p val in the list if the list does not contain
516 an item with key equal to \p val.
518 Returns \p true if \p val is linked into the list, \p false otherwise.
520 bool insert( value_type& val )
522 return insert_at( &m_Head, val );
527 This function is intended for derived non-intrusive containers.
529 The function allows to split new item creating into two part:
530 - create item with key only
531 - insert new item into the list
532 - if inserting is success, calls \p f functor to initialize value-field of \p val.
534 The functor signature is:
536 void func( value_type& val );
538 where \p val is the item inserted.
539 While the functor \p f is called the item \p val is locked so
540 the functor has an exclusive access to the item.
541 The user-defined functor is called only if the inserting is success.
543 template <typename Func>
544 bool insert( value_type& val, Func f )
546 return insert_at( &m_Head, val, f );
551 The operation performs inserting or changing data with lock-free manner.
553 If the item \p val not found in the list, then \p val is inserted into the list
554 iff \p bAllowInsert is \p true.
555 Otherwise, the functor \p func is called with item found.
556 The functor signature is:
559 void operator()( bool bNew, value_type& item, value_type& val );
563 - \p bNew - \p true if the item has been inserted, \p false otherwise
564 - \p item - item of the list
565 - \p val - argument \p val passed into the \p update() function
566 If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
567 refer to the same thing.
569 The functor may change non-key fields of the \p item.
570 While the functor \p f is working the item \p item is locked,
571 so \p func has exclusive access to the item.
573 Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successfull,
574 \p second is \p true if new item has been added or \p false if the item with \p key
575 already is in the list.
577 The function makes RCU lock internally.
579 template <typename Func>
580 std::pair<bool, bool> update( value_type& val, Func func, bool bAllowInsert = true )
582 return update_at( &m_Head, val, func, bAllowInsert );
585 template <typename Func>
586 CDS_DEPRECATED("ensure() is deprecated, use update()")
587 std::pair<bool, bool> ensure( value_type& val, Func func )
589 return update( val, func, true );
593 /// Unlinks the item \p val from the list
595 The function searches the item \p val in the list and unlink it from the list
596 if it is found and it is equal to \p val.
598 Difference between \ref erase and \p unlink functions: \p erase finds <i>a key</i>
599 and deletes the item found. \p unlink finds an item by key and deletes it
600 only if \p val is an item of that list, i.e. the pointer to item found
601 is equal to <tt> &val </tt>.
603 The function returns \p true if success and \p false otherwise.
605 \p disposer specified in \p Traits is called for unlinked item.
607 bool unlink( value_type& val )
609 return unlink_at( &m_Head, val );
612 /// Deletes the item from the list
613 /** \anchor cds_intrusive_LazyList_hp_erase_val
614 The function searches an item with key equal to \p key in the list,
615 unlinks it from the list, and returns \p true.
616 If the item with the key equal to \p key is not found the function return \p false.
618 \p disposer specified in \p Traits is called for deleted item.
620 template <typename Q>
621 bool erase( Q const& key )
623 return erase_at( &m_Head, key, key_comparator());
626 /// Deletes the item from the list using \p pred predicate for searching
628 The function is an analog of \ref cds_intrusive_LazyList_hp_erase_val "erase(Q const&)"
629 but \p pred is used for key comparing.
630 \p Less functor has the interface like \p std::less.
631 \p pred must imply the same element order as the comparator used for building the list.
633 \p disposer specified in \p Traits is called for deleted item.
635 template <typename Q, typename Less>
636 bool erase_with( Q const& key, Less pred )
639 return erase_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>());
642 /// Deletes the item from the list
643 /** \anchor cds_intrusive_LazyList_hp_erase_func
644 The function searches an item with key equal to \p key in the list,
645 call \p func functor with item found, unlinks it from the list, and returns \p true.
646 The \p Func interface is
649 void operator()( value_type const& item );
653 If \p key is not found the function return \p false.
655 \p disposer specified in \p Traits is called for deleted item.
657 template <typename Q, typename Func>
658 bool erase( const Q& key, Func func )
660 return erase_at( &m_Head, key, key_comparator(), func );
663 /// Deletes the item from the list using \p pred predicate for searching
665 The function is an analog of \ref cds_intrusive_LazyList_hp_erase_func "erase(Q const&, Func)"
666 but \p pred is used for key comparing.
667 \p Less functor has the interface like \p std::less.
668 \p pred must imply the same element order as the comparator used for building the list.
670 \p disposer specified in \p Traits is called for deleted item.
672 template <typename Q, typename Less, typename Func>
673 bool erase_with( const Q& key, Less pred, Func func )
676 return erase_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), func );
679 /// Extracts the item from the list with specified \p key
680 /** \anchor cds_intrusive_LazyList_hp_extract
681 The function searches an item with key equal to \p key,
682 unlinks it from the list, and returns it as \p guarded_ptr.
683 If \p key is not found the function returns an empty guarded pointer.
685 Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
687 The \ref disposer specified in \p Traits class template parameter is called automatically
688 by garbage collector \p GC specified in class' template parameters when returned \p guarded_ptr object
689 will be destroyed or released.
690 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
694 typedef cds::intrusive::LazyList< cds::gc::HP, foo, my_traits > ord_list;
698 ord_list::guarded_ptr gp( theList.extract( 5 ));
702 // Destructor of gp releases internal HP guard
706 template <typename Q>
707 guarded_ptr extract( Q const& key )
710 extract_at( &m_Head, gp.guard(), key, key_comparator());
714 /// Extracts the item from the list with comparing functor \p pred
716 The function is an analog of \ref cds_intrusive_LazyList_hp_extract "extract(Q const&)"
717 but \p pred predicate is used for key comparing.
719 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
721 \p pred must imply the same element order as the comparator used for building the list.
723 template <typename Q, typename Less>
724 guarded_ptr extract_with( Q const& key, Less pred )
728 extract_at( &m_Head, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>());
732 /// Finds the key \p key
733 /** \anchor cds_intrusive_LazyList_hp_find
734 The function searches the item with key equal to \p key and calls the functor \p f for item found.
735 The interface of \p Func functor is:
738 void operator()( value_type& item, Q& key );
741 where \p item is the item found, \p key is the <tt>find</tt> function argument.
743 The functor may change non-key fields of \p item.
744 While the functor \p f is calling the item \p item is locked.
746 The function returns \p true if \p key is found, \p false otherwise.
748 template <typename Q, typename Func>
749 bool find( Q& key, Func f )
751 return find_at( &m_Head, key, key_comparator(), f );
754 template <typename Q, typename Func>
755 bool find( Q const& key, Func f )
757 return find_at( &m_Head, key, key_comparator(), f );
761 /// Finds the key \p key using \p pred predicate for searching
763 The function is an analog of \ref cds_intrusive_LazyList_hp_find "find(Q&, Func)"
764 but \p pred is used for key comparing.
765 \p Less functor has the interface like \p std::less.
766 \p pred must imply the same element order as the comparator used for building the list.
768 template <typename Q, typename Less, typename Func>
769 bool find_with( Q& key, Less pred, Func f )
772 return find_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), f );
775 template <typename Q, typename Less, typename Func>
776 bool find_with( Q const& key, Less pred, Func f )
779 return find_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), f );
783 /// Checks whether the list contains \p key
785 The function searches the item with key equal to \p key
786 and returns \p true if it is found, and \p false otherwise.
788 template <typename Q>
789 bool contains( Q const& key )
791 return find_at( &m_Head, key, key_comparator());
794 template <typename Q>
795 CDS_DEPRECATED("deprecated, use contains()")
796 bool find( Q const& key )
798 return contains( key );
802 /// Checks whether the map contains \p key using \p pred predicate for searching
804 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
805 \p Less functor has the interface like \p std::less.
806 \p Less must imply the same element order as the comparator used for building the list.
808 template <typename Q, typename Less>
809 bool contains( Q const& key, Less pred )
812 return find_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>());
815 template <typename Q, typename Less>
816 CDS_DEPRECATED("deprecated, use contains()")
817 bool find_with( Q const& key, Less pred )
819 return contains( key, pred );
823 /// Finds \p key and return the item found
824 /** \anchor cds_intrusive_LazyList_hp_get
825 The function searches the item with key equal to \p key
826 and returns an guarded pointer to it.
827 If \p key is not found the function returns an empty guarded pointer.
829 The \ref disposer specified in \p Traits class template parameter is called
830 by garbage collector \p GC automatically when returned \p guarded_ptr object
831 will be destroyed or released.
832 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
836 typedef cds::intrusive::LazyList< cds::gc::HP, foo, my_traits > ord_list;
840 ord_list::guarded_ptr gp(theList.get( 5 ));
845 // Destructor of guarded_ptr releases internal HP guard
849 Note the compare functor specified for class \p Traits template parameter
850 should accept a parameter of type \p Q that can be not the same as \p value_type.
852 template <typename Q>
853 guarded_ptr get( Q const& key )
856 get_at( &m_Head, gp.guard(), key, key_comparator());
860 /// Finds \p key and return the item found
862 The function is an analog of \ref cds_intrusive_LazyList_hp_get "get( Q const&)"
863 but \p pred is used for comparing the keys.
865 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
867 \p pred must imply the same element order as the comparator used for building the list.
869 template <typename Q, typename Less>
870 guarded_ptr get_with( Q const& key, Less pred )
874 get_at( &m_Head, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>());
881 typename gc::Guard guard;
884 h = m_Head.m_pNext.load( memory_model::memory_order_relaxed );
885 guard.assign( node_traits::to_value_ptr( h.ptr()));
886 if ( m_Head.m_pNext.load(memory_model::memory_order_acquire) == h ) {
887 m_Head.m_Lock.lock();
890 unlink_node( &m_Head, h.ptr(), &m_Head );
894 m_Head.m_Lock.unlock();
896 retire_node( h.ptr()) ; // free node
901 /// Checks if the list is empty
904 return m_Head.m_pNext.load( memory_model::memory_order_relaxed ).ptr() == &m_Tail;
907 /// Returns list's item count
909 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
910 this function always returns 0.
912 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
913 is empty. To check list emptyness use \p empty() method.
917 return m_ItemCounter.value();
922 // split-list support
923 bool insert_aux_node( node_type * pNode )
925 return insert_aux_node( &m_Head, pNode );
928 // split-list support
929 bool insert_aux_node( node_type * pHead, node_type * pNode )
931 assert( pNode != nullptr );
933 // Hack: convert node_type to value_type.
934 // In principle, auxiliary node cannot be reducible to value_type
935 // We assume that internal comparator can correctly distinguish aux and regular node.
936 return insert_at( pHead, *node_traits::to_value_ptr( pNode ));
939 bool insert_at( node_type * pHead, value_type& val )
945 search( pHead, val, pos, key_comparator());
947 scoped_position_lock alp( pos );
948 if ( validate( pos.pPred, pos.pCur )) {
949 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
950 // failed: key already in list
954 link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
963 template <typename Func>
964 bool insert_at( node_type * pHead, value_type& val, Func f )
970 search( pHead, val, pos, key_comparator());
972 scoped_position_lock alp( pos );
973 if ( validate( pos.pPred, pos.pCur )) {
974 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
975 // failed: key already in list
979 link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
989 template <typename Func>
990 std::pair<bool, bool> update_at( node_type * pHead, value_type& val, Func func, bool bAllowInsert )
996 search( pHead, val, pos, key_comparator());
998 scoped_position_lock alp( pos );
999 if ( validate( pos.pPred, pos.pCur )) {
1000 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
1001 // key already in the list
1003 func( false, *node_traits::to_value_ptr( *pos.pCur ) , val );
1004 return std::make_pair( true, false );
1008 if ( !bAllowInsert )
1009 return std::make_pair( false, false );
1011 link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
1012 func( true, val, val );
1014 return std::make_pair( true, true );
1021 bool unlink_at( node_type * pHead, value_type& val )
1027 search( pHead, val, pos, key_comparator());
1031 scoped_position_lock alp( pos );
1032 if ( validate( pos.pPred, pos.pCur )) {
1033 if ( pos.pCur != &m_Tail
1034 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0
1035 && node_traits::to_value_ptr( pos.pCur ) == &val )
1038 unlink_node( pos.pPred, pos.pCur, pHead );
1047 if ( nResult > 0 ) {
1048 retire_node( pos.pCur );
1057 template <typename Q, typename Compare, typename Func>
1058 bool erase_at( node_type * pHead, const Q& val, Compare cmp, Func f, position& pos )
1061 search( pHead, val, pos, cmp );
1065 scoped_position_lock alp( pos );
1066 if ( validate( pos.pPred, pos.pCur )) {
1067 if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
1069 unlink_node( pos.pPred, pos.pCur, pHead );
1070 f( *node_traits::to_value_ptr( *pos.pCur ));
1080 if ( nResult > 0 ) {
1081 retire_node( pos.pCur );
1090 template <typename Q, typename Compare, typename Func>
1091 bool erase_at( node_type * pHead, const Q& val, Compare cmp, Func f )
1094 return erase_at( pHead, val, cmp, f, pos );
1097 template <typename Q, typename Compare>
1098 bool erase_at( node_type * pHead, const Q& val, Compare cmp )
1101 return erase_at( pHead, val, cmp, [](value_type const &){}, pos );
1104 template <typename Q, typename Compare>
1105 bool extract_at( node_type * pHead, typename guarded_ptr::native_guard& gp, const Q& val, Compare cmp )
1108 if ( erase_at( pHead, val, cmp, [](value_type const &){}, pos )) {
1109 gp.set( pos.guards.template get<value_type>(position::guard_current_item));
1115 template <typename Q, typename Compare, typename Func>
1116 bool find_at( node_type * pHead, Q& val, Compare cmp, Func f )
1120 search( pHead, val, pos, cmp );
1121 if ( pos.pCur != &m_Tail ) {
1122 std::unique_lock< typename node_type::lock_type> al( pos.pCur->m_Lock );
1123 if ( !pos.pCur->is_marked()
1124 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 )
1126 f( *node_traits::to_value_ptr( *pos.pCur ), val );
1133 template <typename Q, typename Compare>
1134 bool find_at( node_type * pHead, Q const& val, Compare cmp )
1138 search( pHead, val, pos, cmp );
1139 return pos.pCur != &m_Tail
1140 && !pos.pCur->is_marked()
1141 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0;
1144 template <typename Q, typename Compare>
1145 bool get_at( node_type * pHead, typename guarded_ptr::native_guard& gp, Q const& val, Compare cmp )
1149 search( pHead, val, pos, cmp );
1150 if ( pos.pCur != &m_Tail
1151 && !pos.pCur->is_marked()
1152 && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 )
1154 gp.set( pos.guards.template get<value_type>( position::guard_current_item ));
1164 template <typename Q, typename Compare>
1165 void search( node_type * pHead, const Q& key, position& pos, Compare cmp )
1167 node_type const* pTail = &m_Tail;
1169 marked_node_ptr pCur( pHead );
1170 marked_node_ptr pPrev( pHead );
1172 while ( pCur.ptr() != pTail ) {
1173 if ( pCur.ptr() != pHead ) {
1174 if ( cmp( *node_traits::to_value_ptr( *pCur.ptr()), key ) >= 0 )
1178 pos.guards.copy( position::guard_prev_item, position::guard_current_item );
1181 pCur = pos.guards.protect( position::guard_current_item, pPrev->m_pNext,
1182 []( marked_node_ptr p ) { return node_traits::to_value_ptr( p.ptr()); }
1184 assert( pCur.ptr() != nullptr );
1186 pPrev = pCur = pHead;
1189 pos.pCur = pCur.ptr();
1190 pos.pPred = pPrev.ptr();
1193 static bool validate( node_type * pPred, node_type * pCur )
1195 return !pPred->is_marked()
1196 && !pCur->is_marked()
1197 && pPred->m_pNext.load(memory_model::memory_order_relaxed) == pCur;
1202 }} // namespace cds::intrusive
1204 #endif // CDSLIB_INTRUSIVE_IMPL_LAZY_LIST_H