3 #ifndef __CDS_CONTAINER_MICHAEL_KVLIST_RCU_H
4 #define __CDS_CONTAINER_MICHAEL_KVLIST_RCU_H
7 #include <functional> // ref
8 #include <cds/container/details/michael_list_base.h>
9 #include <cds/intrusive/michael_list_rcu.h>
10 #include <cds/container/details/make_michael_kvlist.h>
12 namespace cds { namespace container {
14 /// Michael's ordered list (key-value pair), template specialization for \ref cds_urcu_desc "RCU"
15 /** @ingroup cds_nonintrusive_list
16 \anchor cds_nonintrusive_MichaelKVList_rcu
18 This is key-value variation of non-intrusive \ref cds_nonintrusive_MichaelList_rcu "MichaelList".
19 Like standard container, this implementation split a value stored into two part -
20 constant key and alterable value.
22 Usually, ordered single-linked list is used as a building block for the hash table implementation.
23 The complexity of searching is <tt>O(N)</tt>.
26 - \p RCU - one of \ref cds_urcu_gc "RCU type"
27 - \p Key - key type of an item stored in the list. It should be copy-constructible
28 - \p Value - value type stored in a list
29 - \p Traits - type traits, default is \p michael_list::traits
31 @note Before including <tt><cds/container/michael_kvlist_rcu.h></tt> you should include appropriate RCU header file,
32 see \ref cds_urcu_gc "RCU type" for list of existing RCU class and corresponding header files.
34 It is possible to declare option-based list using \p cds::container::michael_list::make_traits metafunction istead of \p Traits template
35 argument. For example, the following traits-based declaration of Michael's list
37 #include <cds/urcu/general_buffered.h>
38 #include <cds/container/michael_kvlist_rcu.h>
39 // Declare comparator for the item
41 int operator ()( int i1, int i2 )
48 struct my_traits: public cds::container::michael_list::traits
50 typedef my_compare compare;
53 // Declare traits-based list
54 typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, int, my_traits > traits_based_list;
57 is equivalent for the following option-based list
59 #include <cds/urcu/general_buffered.h>
60 #include <cds/container/michael_kvlist_rcu.h>
62 // my_compare is the same
64 // Declare option-based list
65 typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, int,
66 typename cds::container::michael_list::make_traits<
67 cds::container::opt::compare< my_compare > // item comparator option
76 #ifdef CDS_DOXYGEN_INVOKED
77 typename Traits = michael_list::traits
82 class MichaelKVList< cds::urcu::gc<RCU>, Key, Value, Traits >:
83 #ifdef CDS_DOXYGEN_INVOKED
84 protected intrusive::MichaelList< cds::urcu::gc<RCU>, implementation_defined, Traits >
86 protected details::make_michael_kvlist< cds::urcu::gc<RCU>, Key, Value, Traits >::type
90 typedef details::make_michael_kvlist< cds::urcu::gc<RCU>, Key, Value, Traits > maker;
91 typedef typename maker::type base_class;
95 typedef cds::urcu::gc<RCU> gc; ///< Garbage collector
97 #ifdef CDS_DOXYGEN_INVOKED
98 typedef Key key_type; ///< Key type
99 typedef Value mapped_type; ///< Type of value stored in the list
100 typedef std::pair<key_type const, mapped_type> value_type; ///< key/value pair stored in the list
102 typedef typename maker::key_type key_type;
103 typedef typename maker::value_type mapped_type;
104 typedef typename maker::pair_type value_type;
106 typedef Traits traits; ///< List traits
108 typedef typename base_class::back_off back_off; ///< Back-off strategy
109 typedef typename maker::allocator_type allocator_type; ///< Allocator type used for allocate/deallocate the nodes
110 typedef typename base_class::item_counter item_counter; ///< Item counting policy
111 typedef typename maker::key_comparator key_comparator; ///< key comparison functor
112 typedef typename base_class::memory_model memory_model; ///< Memory ordering. See \p michael_list::traits::memory_model
113 typedef typename base_class::rcu_check_deadlock rcu_check_deadlock ; ///< RCU deadlock checking policy
115 typedef typename gc::scoped_lock rcu_lock ; ///< RCU scoped lock
116 static CDS_CONSTEXPR const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal; ///< Group of \p extract_xxx functions require external locking
120 typedef typename base_class::value_type node_type;
121 typedef typename maker::cxx_allocator cxx_allocator;
122 typedef typename maker::node_deallocator node_deallocator;
123 typedef typename maker::intrusive_traits::compare intrusive_key_comparator;
125 typedef typename base_class::atomic_node_ptr head_type;
129 /// pointer to extracted node
130 typedef cds::urcu::exempt_ptr< gc, node_type, value_type, typename maker::intrusive_traits::disposer,
131 cds::urcu::details::conventional_exempt_pair_cast<node_type, value_type>
136 template <typename K>
137 static node_type * alloc_node(const K& key)
139 return cxx_allocator().New( key );
142 template <typename K, typename V>
143 static node_type * alloc_node( const K& key, const V& val )
145 return cxx_allocator().New( key, val );
148 template <typename K, typename... Args>
149 static node_type * alloc_node( K&& key, Args&&... args )
151 return cxx_allocator().MoveNew( std::forward<K>(key), std::forward<Args>(args)...);
154 static void free_node( node_type * pNode )
156 cxx_allocator().Delete( pNode );
159 struct node_disposer {
160 void operator()( node_type * pNode )
165 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
169 return base_class::m_pHead;
172 head_type& head() const
174 return const_cast<head_type&>( base_class::m_pHead );
180 template <bool IsConst>
181 class iterator_type: protected base_class::template iterator_type<IsConst>
183 typedef typename base_class::template iterator_type<IsConst> iterator_base;
185 iterator_type( head_type const& pNode )
186 : iterator_base( pNode )
189 friend class MichaelKVList;
192 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
193 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
195 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
196 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
201 iterator_type( iterator_type const& src )
202 : iterator_base( src )
205 key_type const& key() const
207 typename iterator_base::value_ptr p = iterator_base::operator ->();
208 assert( p != nullptr );
209 return p->m_Data.first;
212 pair_ptr operator ->() const
214 typename iterator_base::value_ptr p = iterator_base::operator ->();
215 return p ? &(p->m_Data) : nullptr;
218 pair_ref operator *() const
220 typename iterator_base::value_ref p = iterator_base::operator *();
224 value_ref val() const
226 typename iterator_base::value_ptr p = iterator_base::operator ->();
227 assert( p != nullptr );
228 return p->m_Data.second;
232 iterator_type& operator ++()
234 iterator_base::operator ++();
239 bool operator ==(iterator_type<C> const& i ) const
241 return iterator_base::operator ==(i);
244 bool operator !=(iterator_type<C> const& i ) const
246 return iterator_base::operator !=(i);
253 typedef iterator_type<false> iterator;
255 /// Const forward iterator
256 typedef iterator_type<true> const_iterator;
258 /// Returns a forward iterator addressing the first element in a list
260 For empty list \code begin() == end() \endcode
264 return iterator( head() );
267 /// Returns an iterator that addresses the location succeeding the last element in a list
269 Do not use the value returned by <tt>end</tt> function to access any item.
270 Internally, <tt>end</tt> returning value equals to \p nullptr.
272 The returned value can be used only to control reaching the end of the list.
273 For empty list \code begin() == end() \endcode
280 /// Returns a forward const iterator addressing the first element in a list
282 const_iterator begin() const
284 return const_iterator( head() );
286 const_iterator cbegin()
288 return const_iterator( head() );
292 /// Returns an const iterator that addresses the location succeeding the last element in a list
294 const_iterator end() const
296 return const_iterator();
298 const_iterator cend()
300 return const_iterator();
305 /// Default constructor
307 Initializes empty list
321 /// Inserts new node with key and default value
323 The function creates a node with \p key and default value, and then inserts the node created into the list.
326 - The \ref key_type should be constructible from value of type \p K.
327 In trivial case, \p K is equal to \ref key_type.
328 - The \ref mapped_type should be default-constructible.
330 The function makes RCU lock internally.
332 Returns \p true if inserting successful, \p false otherwise.
334 template <typename K>
335 bool insert( const K& key )
337 return insert_at( head(), key );
340 /// Inserts new node with a key and a value
342 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
345 - The \ref key_type should be constructible from \p key of type \p K.
346 - The \ref mapped_type should be constructible from \p val of type \p V.
348 The function makes RCU lock internally.
350 Returns \p true if inserting successful, \p false otherwise.
352 template <typename K, typename V>
353 bool insert( const K& key, const V& val )
355 return insert_at( head(), key, val );
358 /// Inserts new node and initialize it by a functor
360 This function inserts new node with key \p key and if inserting is successful then it calls
361 \p func functor with signature
364 void operator()( value_type& item );
368 The argument \p item of user-defined functor \p func is the reference
369 to the list's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
370 User-defined functor \p func should guarantee that during changing item's value no any other changes
371 could be made on this list's item by concurrent threads.
372 The user-defined functor can be passed by reference using \p std::ref
373 and it is called only if inserting is successful.
375 The key_type should be constructible from value of type \p K.
377 The function allows to split creating of new item into two part:
378 - create item from \p key;
379 - insert new item into the list;
380 - if inserting is successful, initialize the value of item by calling \p func functor
382 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
383 it is preferable that the initialization should be completed only if inserting is successful.
385 The function makes RCU lock internally.
387 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
389 template <typename K, typename Func>
390 bool insert_key( const K& key, Func func )
392 return insert_key_at( head(), key, func );
395 /// Ensures that the \p key exists in the list
397 The operation performs inserting or changing data with lock-free manner.
399 If the \p key not found in the list, then the new item created from \p key
400 is inserted into the list (note that in this case the \ref key_type should be
401 copy-constructible from type \p K).
402 Otherwise, the functor \p func is called with item found.
403 The functor \p Func may be a function with signature:
405 void func( bool bNew, value_type& item );
410 void operator()( bool bNew, value_type& item );
415 - \p bNew - \p true if the item has been inserted, \p false otherwise
416 - \p item - item of the list
418 The functor may change any fields of the \p item.second that is \ref mapped_type;
419 however, \p func must guarantee that during changing no any other modifications
420 could be made on this item by concurrent threads.
422 You may pass \p func argument by reference using \p std::ref
424 The function makes RCU lock internally.
426 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
427 \p second is true if new item has been added or \p false if the item with \p key
428 already is in the list.
430 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
432 template <typename K, typename Func>
433 std::pair<bool, bool> ensure( const K& key, Func f )
435 return ensure_at( head(), key, f );
438 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
440 Returns \p true if inserting successful, \p false otherwise.
442 The function makes RCU lock internally.
444 template <typename K, typename... Args>
445 bool emplace( K&& key, Args&&... args )
447 return emplace_at( head(), std::forward<K>(key), std::forward<Args>(args)... );
450 /// Deletes \p key from the list
451 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase
453 RCU \p synchronize method can be called. RCU should not be locked.
455 Returns \p true if \p key is found and has been deleted, \p false otherwise
457 template <typename K>
458 bool erase( K const& key )
460 return erase_at( head(), key, intrusive_key_comparator() );
463 /// Deletes the item from the list using \p pred predicate for searching
465 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_erase "erase(K const&)"
466 but \p pred is used for key comparing.
467 \p Less functor has the interface like \p std::less.
468 \p pred must imply the same element order as the comparator used for building the list.
470 template <typename K, typename Less>
471 bool erase_with( K const& key, Less pred )
473 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
476 /// Deletes \p key from the list
477 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase_func
478 The function searches an item with key \p key, calls \p f functor
479 and deletes the item. If \p key is not found, the functor is not called.
481 The functor \p Func interface:
484 void operator()(value_type& val) { ... }
487 The functor may be passed by reference with <tt>boost:ref</tt>
489 RCU \p synchronize method can be called. RCU should not be locked.
491 Return \p true if key is found and deleted, \p false otherwise
495 template <typename K, typename Func>
496 bool erase( K const& key, Func f )
498 return erase_at( head(), key, intrusive_key_comparator(), f );
501 /// Deletes the item from the list using \p pred predicate for searching
503 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_erase_func "erase(K const&, Func)"
504 but \p pred is used for key comparing.
505 \p Less functor has the interface like \p std::less.
506 \p pred must imply the same element order as the comparator used for building the list.
508 template <typename K, typename Less, typename Func>
509 bool erase_with( K const& key, Less pred, Func f )
511 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
514 /// Extracts an item from the list
516 @anchor cds_nonintrusive_MichaelKVList_rcu_extract
517 The function searches an item with key equal to \p key in the list,
518 unlinks it from the list, and returns pointer to an item found in \p dest argument.
519 If \p key is not found the function returns \p false.
521 @note The function does NOT call RCU read-side lock or synchronization,
522 and does NOT dispose the item found. It just excludes the item from the list
523 and returns a pointer to item found.
524 You should lock RCU before calling this function.
527 #include <cds/urcu/general_buffered.h>
528 #include <cds/container/michael_kvlist_rcu.h>
530 typedef cds::urcu::gc< general_buffered<> > rcu;
531 typedef cds::container::MichaelKVList< rcu, int, Foo > rcu_michael_list;
533 rcu_michael_list theList;
536 rcu_michael_list::exempt_ptr p;
538 // first, we should lock RCU
539 rcu_michael_list::rcu_lock sl;
541 // Now, you can apply extract function
542 // Note that you must not delete the item found inside the RCU lock
543 if ( theList.extract( p, 10 )) {
544 // do something with p
548 // Outside RCU lock section we may safely release extracted pointer.
549 // release() passes the pointer to RCU reclamation cycle.
553 template <typename K>
554 bool extract( exempt_ptr& dest, K const& key )
556 dest = extract_at( head(), key, intrusive_key_comparator() );
557 return !dest.empty();
560 /// Extracts an item from the list using \p pred predicate for searching
562 This function is the analog for \ref cds_nonintrusive_MichaelKVList_rcu_extract "extract(exempt_ptr&, K const&)".
563 The \p pred is a predicate used for key comparing.
564 \p Less has the interface like \p std::less.
565 \p pred must imply the same element order as \ref key_comparator.
567 template <typename K, typename Less>
568 bool extract_with( exempt_ptr& dest, K const& key, Less pred )
570 dest = extract_at( head(), key, typename maker::template less_wrapper<Less>::type() );
571 return !dest.empty();
574 /// Finds the key \p key
575 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_val
577 The function searches the item with key equal to \p key
578 and returns \p true if it is found, and \p false otherwise
580 The function makes RCU lock internally.
582 template <typename Q>
583 bool find( Q const& key ) const
585 return find_at( head(), key, intrusive_key_comparator() );
588 /// Finds the key \p key using \p pred predicate for searching
590 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_val "find(Q const&)"
591 but \p pred is used for key comparing.
592 \p Less functor has the interface like \p std::less.
593 \p pred must imply the same element order as the comparator used for building the list.
595 template <typename Q, typename Less>
596 bool find_with( Q const& key, Less pred ) const
598 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
601 /// Finds \p key and performs an action with it
602 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_func
603 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
604 The interface of \p Func functor is:
607 void operator()( value_type& item );
610 where \p item is the item found.
612 The functor may change <tt>item.second</tt> that is reference to value of node.
613 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
614 The function does not serialize simultaneous access to the list \p item. If such access is
615 possible you must provide your own synchronization schema to exclude unsafe item modifications.
617 The function makes RCU lock internally.
619 The function returns \p true if \p key is found, \p false otherwise.
621 template <typename Q, typename Func>
622 bool find( Q const& key, Func f ) const
624 return find_at( head(), key, intrusive_key_comparator(), f );
627 /// Finds the key \p val using \p pred predicate for searching
629 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_func "find(Q const&, Func)"
630 but \p pred is used for key comparing.
631 \p Less functor has the interface like \p std::less.
632 \p pred must imply the same element order as the comparator used for building the list.
634 template <typename Q, typename Less, typename Func>
635 bool find_with( Q const& key, Less pred, Func f ) const
637 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
640 /// Finds \p key and return the item found
641 /** \anchor cds_nonintrusive_MichaelKVList_rcu_get
642 The function searches the item with \p key and returns the pointer to item found.
643 If \p key is not found it returns \p nullptr.
645 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
647 RCU should be locked before call of this function.
648 Returned item is valid only while RCU is locked:
650 typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, foo, my_traits > ord_list;
655 ord_list::rcu_lock lock;
657 ord_list::value_type * pVal = theList.get( 5 );
662 // Unlock RCU by rcu_lock destructor
663 // pVal can be freed at any time after RCU has been unlocked
667 template <typename K>
668 value_type * get( K const& key ) const
670 return get_at( head(), key, intrusive_key_comparator());
673 /// Finds \p key and return the item found
675 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_get "get(K const&)"
676 but \p pred is used for comparing the keys.
678 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
680 \p pred must imply the same element order as the comparator used for building the list.
682 template <typename K, typename Less>
683 value_type * get_with( K const& key, Less pred ) const
685 return get_at( head(), key, typename maker::template less_wrapper<Less>::type() );
688 /// Checks if the list is empty
691 return base_class::empty();
694 /// Returns list's item count
696 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
697 this function always returns 0.
699 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
700 is empty. To check list emptyness use \p empty() method.
704 return base_class::size();
709 Post-condition: the list is empty
718 bool insert_node_at( head_type& refHead, node_type * pNode )
720 assert( pNode != nullptr );
721 scoped_node_ptr p( pNode );
722 if ( base_class::insert_at( refHead, *pNode )) {
729 template <typename K>
730 bool insert_at( head_type& refHead, const K& key )
732 return insert_node_at( refHead, alloc_node( key ));
735 template <typename K, typename V>
736 bool insert_at( head_type& refHead, const K& key, const V& val )
738 return insert_node_at( refHead, alloc_node( key, val ));
741 template <typename K, typename Func>
742 bool insert_key_at( head_type& refHead, const K& key, Func f )
744 scoped_node_ptr pNode( alloc_node( key ));
746 if ( base_class::insert_at( refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); })) {
753 template <typename K, typename... Args>
754 bool emplace_at( head_type& refHead, K&& key, Args&&... args )
756 return insert_node_at( refHead, alloc_node( std::forward<K>(key), std::forward<Args>(args)... ));
759 template <typename K, typename Func>
760 std::pair<bool, bool> ensure_at( head_type& refHead, const K& key, Func f )
762 scoped_node_ptr pNode( alloc_node( key ));
764 std::pair<bool, bool> ret = base_class::ensure_at( refHead, *pNode,
765 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); });
766 if ( ret.first && ret.second )
772 template <typename K, typename Compare>
773 bool erase_at( head_type& refHead, K const& key, Compare cmp )
775 return base_class::erase_at( refHead, key, cmp );
778 template <typename K, typename Compare, typename Func>
779 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
781 return base_class::erase_at( refHead, key, cmp, [&f]( node_type const & node ){ f( const_cast<value_type&>(node.m_Data)); });
784 template <typename K, typename Compare>
785 node_type * extract_at( head_type& refHead, K const& key, Compare cmp )
787 return base_class::extract_at( refHead, key, cmp );
790 template <typename K, typename Compare>
791 bool find_at( head_type& refHead, K const& key, Compare cmp ) const
793 return base_class::find_at( refHead, key, cmp, [](node_type&, K const&) {} );
796 template <typename K, typename Compare, typename Func>
797 bool find_at( head_type& refHead, K& key, Compare cmp, Func f ) const
799 return base_class::find_at( refHead, key, cmp, [&f](node_type& node, K const&){ f( node.m_Data ); });
802 template <typename K, typename Compare>
803 value_type * get_at( head_type& refHead, K const& val, Compare cmp ) const
805 node_type * pNode = base_class::get_at( refHead, val, cmp );
806 return pNode ? &pNode->m_Data : nullptr;
812 }} // namespace cds::container
814 #endif // #ifndef __CDS_CONTAINER_MICHAEL_KVLIST_RCU_H