3 #ifndef CDSLIB_INTRUSIVE_MICHAEL_LIST_RCU_H
4 #define CDSLIB_INTRUSIVE_MICHAEL_LIST_RCU_H
6 #include <cds/intrusive/details/michael_list_base.h>
7 #include <cds/urcu/details/check_deadlock.h>
8 #include <cds/details/binary_functor_wrapper.h>
9 #include <cds/details/make_const_type.h>
10 #include <cds/urcu/exempt_ptr.h>
11 #include <cds/urcu/raw_ptr.h>
12 #include <cds/intrusive/details/raw_ptr_disposer.h>
14 namespace cds { namespace intrusive {
17 namespace michael_list {
19 /// Node specialization for uRCU
20 template <class RCU, typename Tag>
21 struct node< cds::urcu::gc< RCU >, Tag >
23 typedef cds::urcu::gc< RCU > gc; ///< Garbage collector
24 typedef Tag tag; ///< tag
26 typedef cds::details::marked_ptr<node, 3> marked_ptr; ///< marked pointer
27 typedef typename gc::template atomic_marked_ptr<marked_ptr> atomic_marked_ptr; ///< atomic marked pointer specific for GC
29 atomic_marked_ptr m_pNext; ///< pointer to the next node in the container
30 node * m_pDelChain; ///< Deleted node chain (local for a thread)
32 CDS_CONSTEXPR node() CDS_NOEXCEPT
34 , m_pDelChain( nullptr )
37 } // namespace michael_list
40 /// Michael's lock-free ordered single-linked list (template specialization for \ref cds_urcu_desc "RCU")
41 /** @ingroup cds_intrusive_list
42 \anchor cds_intrusive_MichaelList_rcu
44 Usually, ordered single-linked list is used as a building block for the hash table implementation.
45 The complexity of searching is <tt>O(N)</tt>.
48 - \p RCU - one of \ref cds_urcu_gc "RCU type"
49 - \p T - type to be stored in the list; the type \p T should be based on (or has a member of type)
50 cds::intrusive::micheal_list::node
51 - \p Traits - type traits. See \p michael_list::traits for explanation. It is possible to declare option-based
52 list with \p cds::intrusive::michael_list::make_traits metafunction,
53 see \ref cds_intrusive_MichaelList_hp "here" for explanations.
56 Before including <tt><cds/intrusive/michael_list_rcu.h></tt> you should include appropriate RCU header file,
57 see \ref cds_urcu_gc "RCU type" for list of existing RCU class and corresponding header files.
58 For example, for \ref cds_urcu_general_buffered_gc "general-purpose buffered RCU" you should include:
60 #include <cds/urcu/general_buffered.h>
61 #include <cds/intrusive/michael_list_rcu.h>
63 // Now, you can declare Michael's list for type Foo and default traits:
64 typedef cds::intrusive::MichaelList<cds::urcu::gc< cds::urcu::general_buffered<> >, Foo > rcu_michael_list;
67 template < typename RCU, typename T,
68 #ifdef CDS_DOXYGEN_INVOKED
69 class Traits = michael_list::traits
74 class MichaelList<cds::urcu::gc<RCU>, T, Traits>
77 typedef T value_type; ///< type of value stored in the list
78 typedef Traits traits; ///< Traits template parameter
80 typedef typename traits::hook hook; ///< hook type
81 typedef typename hook::node_type node_type; ///< node type
83 # ifdef CDS_DOXYGEN_INVOKED
84 typedef implementation_defined key_comparator ; ///< key comparison functor based on opt::compare and opt::less option setter.
86 typedef typename opt::details::make_comparator< value_type, traits >::type key_comparator;
89 typedef typename traits::disposer disposer; ///< disposer used
90 typedef typename get_node_traits< value_type, node_type, hook>::type node_traits ; ///< node traits
91 typedef typename michael_list::get_link_checker< node_type, traits::link_checker >::type link_checker; ///< link checker
93 typedef cds::urcu::gc<RCU> gc; ///< RCU schema
94 typedef typename traits::back_off back_off; ///< back-off strategy
95 typedef typename traits::item_counter item_counter; ///< Item counting policy used
96 typedef typename traits::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
97 typedef typename traits::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
99 typedef typename gc::scoped_lock rcu_lock ; ///< RCU scoped lock
100 static CDS_CONSTEXPR const bool c_bExtractLockExternal = false; ///< Group of \p extract_xxx functions do not require external locking
103 // Rebind traits (split-list support)
104 template <typename... Options>
105 struct rebind_traits {
109 , typename cds::opt::make_options< traits, Options...>::type
115 typedef typename node_type::marked_ptr marked_node_ptr ; ///< Marked node pointer
116 typedef typename node_type::atomic_marked_ptr atomic_node_ptr ; ///< Atomic node pointer
117 typedef atomic_node_ptr auxiliary_head ; ///< Auxiliary head type (for split-list support)
119 atomic_node_ptr m_pHead ; ///< Head pointer
120 item_counter m_ItemCounter ; ///< Item counter
130 typedef cds::urcu::details::check_deadlock_policy< gc, rcu_check_deadlock> check_deadlock_policy;
132 static void clear_links( node_type * pNode )
134 pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_release );
135 pNode->m_pDelChain = nullptr;
138 struct clear_and_dispose {
139 void operator()( value_type * p )
141 assert( p != nullptr );
142 clear_links( node_traits::to_node_ptr(p));
147 static void dispose_node( node_type * pNode )
150 assert( !gc::is_locked() );
152 gc::template retire_ptr<clear_and_dispose>( node_traits::to_value_ptr( *pNode ) );
155 static void dispose_chain( node_type * pChain )
158 assert( !gc::is_locked() );
160 auto f = [&pChain]() -> cds::urcu::retired_ptr {
161 node_type * p = pChain;
163 pChain = p->m_pDelChain;
164 return cds::urcu::make_retired_ptr<clear_and_dispose>( node_traits::to_value_ptr( p ));
166 return cds::urcu::make_retired_ptr<clear_and_dispose>( static_cast<value_type *>(nullptr));
168 gc::batch_retire(std::ref(f));
172 /// Position pointer for item search
174 atomic_node_ptr * pPrev ; ///< Previous node
175 node_type * pCur ; ///< Current node
176 node_type * pNext ; ///< Next node
178 atomic_node_ptr& refHead;
179 node_type * pDelChain; ///< Head of deleted node chain
181 position( atomic_node_ptr& head )
183 , pDelChain( nullptr )
188 dispose_chain( pDelChain );
195 using exempt_ptr = cds::urcu::exempt_ptr< gc, value_type, value_type, clear_and_dispose, void >; ///< pointer to extracted node
199 struct chain_disposer {
200 void operator()( node_type * pChain ) const
202 dispose_chain( pChain );
205 typedef cds::intrusive::details::raw_ptr_disposer< gc, node_type, chain_disposer> raw_ptr_disposer;
209 /// Result of \p get(), \p get_with() functions - pointer to the node found
210 typedef cds::urcu::raw_ptr< gc, value_type, raw_ptr_disposer > raw_ptr;
215 bool link_node( node_type * pNode, position& pos )
217 assert( pNode != nullptr );
218 link_checker::is_empty( pNode );
220 marked_node_ptr p( pos.pCur );
221 pNode->m_pNext.store( p, memory_model::memory_order_release );
222 return pos.pPrev->compare_exchange_strong( p, marked_node_ptr(pNode), memory_model::memory_order_release, atomics::memory_order_relaxed );
225 static void link_to_remove_chain( position& pos, node_type * pDel )
227 assert( pDel->m_pDelChain == nullptr );
229 pDel->m_pDelChain = pos.pDelChain;
230 pos.pDelChain = pDel;
233 bool unlink_node( position& pos, erase_node_mask nMask )
235 assert(gc::is_locked() );
237 // Mark the node (logical deletion)
238 marked_node_ptr next(pos.pNext, 0);
240 if ( pos.pCur->m_pNext.compare_exchange_strong( next, next | nMask, memory_model::memory_order_release, atomics::memory_order_relaxed )) {
242 // Try physical removal - fast path
243 marked_node_ptr cur(pos.pCur);
244 if ( pos.pPrev->compare_exchange_strong(cur, marked_node_ptr(pos.pNext), memory_model::memory_order_acquire, atomics::memory_order_relaxed )) {
245 if ( nMask == erase_mask )
246 link_to_remove_chain( pos, pos.pCur );
250 search( pos.refHead, *node_traits::to_value_ptr( pos.pCur ), pos, key_comparator() );
260 template <bool IsConst>
263 friend class MichaelList;
264 value_type * m_pNode;
269 node_type * p = node_traits::to_node_ptr( *m_pNode )->m_pNext.load(memory_model::memory_order_relaxed).ptr();
270 m_pNode = p ? node_traits::to_value_ptr( p ) : nullptr;
275 explicit iterator_type( node_type * pNode)
278 m_pNode = node_traits::to_value_ptr( *pNode );
282 explicit iterator_type( atomic_node_ptr const& refNode)
284 node_type * pNode = refNode.load(memory_model::memory_order_relaxed).ptr();
285 m_pNode = pNode ? node_traits::to_value_ptr( *pNode ) : nullptr;
289 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
290 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
296 iterator_type( const iterator_type& src )
297 : m_pNode( src.m_pNode )
300 value_ptr operator ->() const
305 value_ref operator *() const
307 assert( m_pNode != nullptr );
312 iterator_type& operator ++()
319 iterator_type operator ++(int)
321 iterator_type i(*this);
326 iterator_type& operator = (const iterator_type& src)
328 m_pNode = src.m_pNode;
333 bool operator ==(iterator_type<C> const& i ) const
335 return m_pNode == i.m_pNode;
338 bool operator !=(iterator_type<C> const& i ) const
340 return m_pNode != i.m_pNode;
347 typedef iterator_type<false> iterator;
348 /// Const forward iterator
349 typedef iterator_type<true> const_iterator;
351 /// Returns a forward iterator addressing the first element in a list
353 For empty list \code begin() == end() \endcode
357 return iterator( m_pHead );
360 /// Returns an iterator that addresses the location succeeding the last element in a list
362 Do not use the value returned by <tt>end</tt> function to access any item.
363 Internally, <tt>end</tt> returning value equals to \p nullptr.
365 The returned value can be used only to control reaching the end of the list.
366 For empty list \code begin() == end() \endcode
373 /// Returns a forward const iterator addressing the first element in a list
374 const_iterator begin() const
376 return const_iterator(m_pHead );
378 /// Returns a forward const iterator addressing the first element in a list
379 const_iterator cbegin() const
381 return const_iterator(m_pHead );
384 /// Returns an const iterator that addresses the location succeeding the last element in a list
385 const_iterator end() const
387 return const_iterator();
389 /// Returns an const iterator that addresses the location succeeding the last element in a list
390 const_iterator cend() const
392 return const_iterator();
396 /// Default constructor initializes empty list
400 static_assert( (std::is_same< gc, typename node_type::gc >::value), "GC and node_type::gc must be the same type" );
411 The function inserts \p val in the list if the list does not contain
412 an item with key equal to \p val.
414 The function makes RCU lock internally.
416 Returns \p true if \p val is linked into the list, \p false otherwise.
418 bool insert( value_type& val )
420 return insert_at( m_pHead, val );
425 This function is intended for derived non-intrusive containers.
427 The function allows to split new item creating into two part:
428 - create item with key only
429 - insert new item into the list
430 - if inserting is success, calls \p f functor to initialize value-field of \p val.
432 The functor signature is:
434 void func( value_type& val );
436 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
437 \p val no any other changes could be made on this list's item by concurrent threads.
438 The user-defined functor is called only if the inserting is success.
440 The function makes RCU lock internally.
442 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
444 template <typename Func>
445 bool insert( value_type& val, Func f )
447 return insert_at( m_pHead, val, f );
450 /// Ensures that the \p item exists in the list
452 The operation performs inserting or changing data with lock-free manner.
454 If the item \p val not found in the list, then \p val is inserted into the list.
455 Otherwise, the functor \p func is called with item found.
456 The functor signature is:
459 void operator()( bool bNew, value_type& item, value_type& val );
463 - \p bNew - \p true if the item has been inserted, \p false otherwise
464 - \p item - item of the list
465 - \p val - argument \p val passed into the \p ensure function
466 If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
467 refer to the same thing.
469 The functor may change non-key fields of the \p item; however, \p func must guarantee
470 that during changing no any other modifications could be made on this item by concurrent threads.
472 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
473 \p second is true if new item has been added or \p false if the item with \p key
474 already is in the list.
476 The function makes RCU lock internally.
478 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
480 template <typename Func>
481 std::pair<bool, bool> ensure( value_type& val, Func func )
483 return ensure_at( m_pHead, val, func );
486 /// Unlinks the item \p val from the list
488 The function searches the item \p val in the list and unlink it from the list
489 if it is found and it is equal to \p val.
491 Difference between \ref erase and \p unlink functions: \p erase finds <i>a key</i>
492 and deletes the item found. \p unlink finds an item by key and deletes it
493 only if \p val is an item of that list, i.e. the pointer to the item found
494 is equal to <tt> &val </tt>.
496 The function returns \p true if success and \p false otherwise.
498 RCU \p synchronize method can be called.
499 Note that depending on RCU type used the \ref disposer call can be deferred.
501 The function can throw cds::urcu::rcu_deadlock exception if deadlock is encountered and
502 deadlock checking policy is opt::v::rcu_throw_deadlock.
504 bool unlink( value_type& val )
506 return unlink_at( m_pHead, val );
509 /// Deletes the item from the list
510 /** \anchor cds_intrusive_MichaelList_rcu_erase_val
511 The function searches an item with key equal to \p key in the list,
512 unlinks it from the list, and returns \p true.
513 If the item with the key equal to \p key is not found the function return \p false.
515 RCU \p synchronize method can be called.
516 Note that depending on RCU type used the \ref disposer call can be deferred.
518 The function can throw \ref cds_urcu_rcu_deadlock "cds::urcu::rcu_deadlock" exception if a deadlock is detected and
519 the deadlock checking policy is \p opt::v::rcu_throw_deadlock.
521 template <typename Q>
522 bool erase( Q const& key )
524 return erase_at( m_pHead, key, key_comparator() );
527 /// Deletes the item from the list using \p pred predicate for searching
529 The function is an analog of \ref cds_intrusive_MichaelList_rcu_erase_val "erase(Q const&)"
530 but \p pred is used for key comparing.
531 \p Less functor has the interface like \p std::less.
532 \p pred must imply the same element order as the comparator used for building the list.
534 template <typename Q, typename Less>
535 bool erase_with( Q const& key, Less pred )
538 return erase_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>() );
541 /// Deletes the item from the list
542 /** \anchor cds_intrusive_MichaelList_rcu_erase_func
543 The function searches an item with key equal to \p key in the list,
544 call \p func functor with item found, unlinks it from the list, and returns \p true.
545 The \p Func interface is
548 void operator()( value_type const& item );
552 If the item with the key equal to \p key is not found the function return \p false.
554 RCU \p synchronize method can be called.
555 Note that depending on RCU type used the \ref disposer call can be deferred.
557 The function can throw \ref cds_urcu_rcu_deadlock "cds::urcu::rcu_deadlock" exception if a deadlock is detected and
558 the deadlock checking policy is \p opt::v::rcu_throw_deadlock.
560 template <typename Q, typename Func>
561 bool erase( Q const& key, Func func )
563 return erase_at( m_pHead, key, key_comparator(), func );
566 /// Deletes the item from the list using \p pred predicate for searching
568 The function is an analog of \ref cds_intrusive_MichaelList_rcu_erase_func "erase(Q const&, Func)"
569 but \p pred is used for key comparing.
570 \p Less functor has the interface like \p std::less.
571 \p pred must imply the same element order as the comparator used for building the list.
573 template <typename Q, typename Less, typename Func>
574 bool erase_with( Q const& key, Less pred, Func func )
577 return erase_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), func );
580 /// Extracts an item from the list
582 @anchor cds_intrusive_MichaelList_rcu_extract
583 The function searches an item with key equal to \p key in the list,
584 unlinks it from the list, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item found.
585 If \p key is not found the function returns an empty \p exempt_ptr.
587 @note The function does NOT dispose the item found. It just unlinks the item from the list
588 and returns a pointer to item found.
589 You shouldn't lock RCU for current thread before calling this function, and you should manually release
590 \p dest exempt pointer outside the RCU lock before reusing it.
593 #include <cds/urcu/general_buffered.h>
594 #include <cds/intrusive/michael_list_rcu.h>
596 typedef cds::urcu::gc< general_buffered<> > rcu;
597 typedef cds::intrusive::MichaelList< rcu, Foo > rcu_michael_list;
599 rcu_michael_list theList;
602 rcu_michael_list::exempt_ptr p1;
604 // The RCU should NOT be locked when extract() is called!
605 assert( !rcu::is_locked() );
607 // You can call extract() function
608 p1 = theList.extract( 10 );
610 // do something with p1
614 // We may safely release p1 here
615 // release() passes the pointer to RCU reclamation cycle:
616 // it invokes RCU retire_ptr function with the disposer you provided for the list.
620 template <typename Q>
621 exempt_ptr extract( Q const& key )
623 return exempt_ptr( extract_at( m_pHead, key, key_comparator() ));
626 /// Extracts an item from the list using \p pred predicate for searching
628 This function is the analog for \p extract(Q const&)
630 The \p pred is a predicate used for key comparing.
631 \p Less has the interface like \p std::less.
632 \p pred must imply the same element order as \ref key_comparator.
634 template <typename Q, typename Less>
635 exempt_ptr extract_with( Q const& key, Less pred )
638 return exempt_ptr( extract_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>() ));
641 /// Find the key \p val
642 /** \anchor cds_intrusive_MichaelList_rcu_find_func
643 The function searches the item with key equal to \p key
644 and calls the functor \p f for item found.
645 The interface of \p Func functor is:
648 void operator()( value_type& item, Q& key );
651 where \p item is the item found, \p key is the <tt>find</tt> function argument.
653 The functor can change non-key fields of \p item.
654 The function \p find does not serialize simultaneous access to the list \p item. If such access is
655 possible you must provide your own synchronization schema to exclude unsafe item modifications.
657 The function makes RCU lock internally.
659 The function returns \p true if \p val is found, \p false otherwise.
661 template <typename Q, typename Func>
662 bool find( Q& key, Func f )
664 return find_at( m_pHead, key, key_comparator(), f );
667 template <typename Q, typename Func>
668 bool find( Q const& key, Func f )
670 return find_at( m_pHead, key, key_comparator(), f );
674 /// Finds \p key using \p pred predicate for searching
676 The function is an analog of \ref cds_intrusive_MichaelList_rcu_find_func "find(Q&, Func)"
677 but \p pred is used for key comparing.
678 \p Less functor has the interface like \p std::less.
679 \p pred must imply the same element order as the comparator used for building the list.
681 template <typename Q, typename Less, typename Func>
682 bool find_with( Q& key, Less pred, Func f )
685 return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
688 template <typename Q, typename Less, typename Func>
689 bool find_with( Q const& key, Less pred, Func f )
692 return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
697 /** \anchor cds_intrusive_MichaelList_rcu_find_val
698 The function searches the item with key equal to \p key
699 and returns \p true if \p val found or \p false otherwise.
701 template <typename Q>
702 bool find( Q const& key )
704 return find_at( m_pHead, key, key_comparator() );
707 /// Finds \p key using \p pred predicate for searching
709 The function is an analog of \ref cds_intrusive_MichaelList_rcu_find_val "find(Q const&)"
710 but \p pred is used for key comparing.
711 \p Less functor has the interface like \p std::less.
712 \p pred must imply the same element order as the comparator used for building the list.
714 template <typename Q, typename Less>
715 bool find_with( Q const& key, Less pred )
718 return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>() );
721 /// Finds \p key and return the item found
722 /** \anchor cds_intrusive_MichaelList_rcu_get
723 The function searches the item with key equal to \p key and returns the pointer to item found.
724 If \p key is not found it returns empty \p raw_ptr object.
726 Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
728 RCU should be locked before call of this function.
729 Returned item is valid only while RCU is locked:
731 typedef cds::intrusive::MichaelList< cds::urcu::gc< cds::urcu::general_buffered<> >, foo, my_traits > ord_list;
734 typename ord_list::raw_ptr rp;
737 ord_list::rcu_lock lock;
739 rp = theList.get( 5 );
744 // Unlock RCU by rcu_lock destructor
745 // Node owned by rp can be retired by disposer at any time after RCU has been unlocked
747 // You can manually release rp after RCU-locked section
751 template <typename Q>
752 raw_ptr get( Q const& key )
754 return get_at( m_pHead, key, key_comparator());
757 /// Finds \p key and return the item found
759 The function is an analog of \ref cds_intrusive_MichaelList_rcu_get "get(Q const&)"
760 but \p pred is used for comparing the keys.
762 \p Less functor has the semantics like \p std::less but should take arguments of type \p value_type and \p Q
764 \p pred must imply the same element order as the comparator used for building the list.
766 template <typename Q, typename Less>
767 raw_ptr get_with( Q const& key, Less pred )
770 return get_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
773 /// Clears the list using default disposer
775 The function clears the list using default (provided by \p Traits class template argument) disposer functor.
777 RCU \p synchronize method can be called.
778 Note that depending on RCU type used the \ref disposer invocation can be deferred.
780 The function can throw \p cds::urcu::rcu_deadlock exception if an deadlock is encountered and
781 deadlock checking policy is \p opt::v::rcu_throw_deadlock.
786 check_deadlock_policy::check();
788 marked_node_ptr pHead;
792 pHead = m_pHead.load(memory_model::memory_order_acquire);
795 marked_node_ptr pNext( pHead->m_pNext.load(memory_model::memory_order_relaxed) );
796 if ( !pHead->m_pNext.compare_exchange_weak( pNext, pNext | 1, memory_model::memory_order_acquire, memory_model::memory_order_relaxed ))
798 if ( !m_pHead.compare_exchange_weak( pHead, marked_node_ptr(pNext.ptr()), memory_model::memory_order_release, memory_model::memory_order_relaxed ))
803 dispose_node( pHead.ptr() );
808 /// Check if the list is empty
811 return m_pHead.load( memory_model::memory_order_relaxed ).all() == nullptr;
814 /// Returns list's item count
816 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
817 this function always returns 0.
819 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
820 is empty. To check list emptyness use \p empty() method.
824 return m_ItemCounter.value();
829 // split-list support
830 bool insert_aux_node( node_type * pNode )
832 return insert_aux_node( m_pHead, pNode );
835 // split-list support
836 bool insert_aux_node( atomic_node_ptr& refHead, node_type * pNode )
838 assert( pNode != nullptr );
840 // Hack: convert node_type to value_type.
841 // In principle, auxiliary node can be non-reducible to value_type
842 // We assume that comparator can correctly distinguish between aux and regular node.
843 return insert_at( refHead, *node_traits::to_value_ptr( pNode ) );
846 bool insert_at( atomic_node_ptr& refHead, value_type& val )
848 position pos( refHead );
851 return insert_at_locked( pos, val );
855 template <typename Func>
856 bool insert_at( atomic_node_ptr& refHead, value_type& val, Func f )
858 link_checker::is_empty( node_traits::to_node_ptr( val ) );
859 position pos( refHead );
864 if ( search( refHead, val, pos, key_comparator()))
867 if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
874 node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
880 iterator insert_at_( atomic_node_ptr& refHead, value_type& val )
883 if ( insert_at_locked( refHead, val ))
884 return iterator( node_traits::to_node_ptr( val ));
888 template <typename Func>
889 std::pair<iterator, bool> ensure_at_( atomic_node_ptr& refHead, value_type& val, Func func )
891 position pos( refHead );
894 return ensure_at_locked( pos, val, func );
898 template <typename Func>
899 std::pair<bool, bool> ensure_at( atomic_node_ptr& refHead, value_type& val, Func func )
901 position pos( refHead );
904 std::pair<iterator, bool> ret = ensure_at_locked( pos, val, func );
905 return std::make_pair( ret.first != end(), ret.second );
909 bool unlink_at( atomic_node_ptr& refHead, value_type& val )
911 position pos( refHead );
913 check_deadlock_policy::check();
918 if ( !search( refHead, val, pos, key_comparator() ) || node_traits::to_value_ptr( *pos.pCur ) != &val )
920 if ( !unlink_node( pos, erase_mask )) {
931 template <typename Q, typename Compare, typename Func>
932 bool erase_at( position& pos, Q const& val, Compare cmp, Func f )
935 check_deadlock_policy::check();
940 if ( !search( pos.refHead, val, pos, cmp ) )
942 if ( !unlink_node( pos, erase_mask )) {
948 f( *node_traits::to_value_ptr( *pos.pCur ) );
954 template <typename Q, typename Compare, typename Func>
955 bool erase_at( atomic_node_ptr& refHead, Q const& val, Compare cmp, Func f )
957 position pos( refHead );
958 return erase_at( pos, val, cmp, f );
961 template <typename Q, typename Compare>
962 bool erase_at( atomic_node_ptr& refHead, const Q& val, Compare cmp )
964 position pos( refHead );
965 return erase_at( pos, val, cmp, [](value_type const&){} );
968 template <typename Q, typename Compare >
969 value_type * extract_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
971 position pos( refHead );
973 assert( !gc::is_locked() ) ; // RCU must not be locked!!!
975 node_type * pExtracted;
979 if ( !search( refHead, val, pos, cmp ) )
981 // store pCur since it may be changed by unlink_node() slow path
982 pExtracted = pos.pCur;
983 if ( !unlink_node( pos, extract_mask )) {
989 value_type * pRet = node_traits::to_value_ptr( pExtracted );
990 assert( pRet->m_pDelChain == nullptr );
996 template <typename Q, typename Compare, typename Func>
997 bool find_at( atomic_node_ptr& refHead, Q& val, Compare cmp, Func f )
999 position pos( refHead );
1003 if ( search( refHead, val, pos, cmp ) ) {
1004 assert( pos.pCur != nullptr );
1005 f( *node_traits::to_value_ptr( *pos.pCur ), val );
1012 template <typename Q, typename Compare>
1013 bool find_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
1015 position pos( refHead );
1018 return find_at_locked( pos, val, cmp ) != cend();
1022 template <typename Q, typename Compare>
1023 raw_ptr get_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
1025 // RCU should be locked!
1026 assert(gc::is_locked() );
1028 position pos( refHead );
1030 if ( search( refHead, val, pos, cmp ))
1031 return raw_ptr( node_traits::to_value_ptr( pos.pCur ), raw_ptr_disposer( pos ));
1032 return raw_ptr( raw_ptr_disposer( pos ));
1039 template <typename Q, typename Compare>
1040 bool search( atomic_node_ptr& refHead, const Q& val, position& pos, Compare cmp )
1042 // RCU lock should be locked!!!
1043 assert( gc::is_locked() );
1045 atomic_node_ptr * pPrev;
1046 marked_node_ptr pNext;
1047 marked_node_ptr pCur;
1053 pCur = pPrev->load(memory_model::memory_order_acquire);
1057 if ( !pCur.ptr() ) {
1060 pos.pNext = nullptr;
1064 pNext = pCur->m_pNext.load(memory_model::memory_order_acquire);
1066 if ( pPrev->load(memory_model::memory_order_acquire) != pCur
1067 || pNext != pCur->m_pNext.load(memory_model::memory_order_acquire))
1073 if ( pNext.bits() ) {
1074 // pCur is marked as deleted. Try to unlink it from the list
1075 if ( pPrev->compare_exchange_weak( pCur, marked_node_ptr( pNext.ptr() ), memory_model::memory_order_acquire, atomics::memory_order_relaxed ) ) {
1076 if ( pNext.bits() == erase_mask )
1077 link_to_remove_chain( pos, pCur.ptr() );
1083 assert( pCur.ptr() != nullptr );
1084 int nCmp = cmp( *node_traits::to_value_ptr( pCur.ptr() ), val );
1087 pos.pCur = pCur.ptr();
1088 pos.pNext = pNext.ptr();
1091 pPrev = &( pCur->m_pNext );
1099 bool insert_at_locked( position& pos, value_type& val )
1101 // RCU lock should be locked!!!
1102 assert( gc::is_locked() );
1103 link_checker::is_empty( node_traits::to_node_ptr( val ) );
1106 if ( search( pos.refHead, val, pos, key_comparator() ) )
1109 if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
1115 node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
1119 template <typename Func>
1120 std::pair<iterator, bool> ensure_at_locked( position& pos, value_type& val, Func func )
1122 // RCU lock should be locked!!!
1123 assert( gc::is_locked() );
1126 if ( search( pos.refHead, val, pos, key_comparator() ) ) {
1127 assert( key_comparator()( val, *node_traits::to_value_ptr( *pos.pCur ) ) == 0 );
1129 func( false, *node_traits::to_value_ptr( *pos.pCur ), val );
1130 return std::make_pair( iterator( pos.pCur ), false );
1133 link_checker::is_empty( node_traits::to_node_ptr( val ) );
1135 if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
1137 func( true, val , val );
1138 return std::make_pair( iterator( node_traits::to_node_ptr( val )), true );
1141 // clear the next field
1142 node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
1147 template <typename Q, typename Compare>
1148 const_iterator find_at_locked( position& pos, Q const& val, Compare cmp )
1150 assert( gc::is_locked() );
1152 if ( search( pos.refHead, val, pos, cmp ) ) {
1153 assert( pos.pCur != nullptr );
1154 return const_iterator( pos.pCur );
1161 }} // namespace cds::intrusive
1163 #endif // #ifndef CDSLIB_INTRUSIVE_MICHAEL_LIST_NOGC_H