3 #ifndef CDSLIB_CONTAINER_MICHAEL_KVLIST_RCU_H
4 #define CDSLIB_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 do not 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 using exempt_ptr = 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>
135 struct raw_ptr_converter
137 value_type * operator()( node_type * p ) const
139 return p ? &p->m_Data : nullptr;
142 value_type& operator()( node_type& n ) const
147 value_type const& operator()( node_type const& n ) const
154 /// Result of \p get(), \p get_with() functions - pointer to the node found
155 typedef cds::urcu::raw_ptr_adaptor< value_type, typename base_class::raw_ptr, raw_ptr_converter > raw_ptr;
159 template <typename K>
160 static node_type * alloc_node(const K& key)
162 return cxx_allocator().New( key );
165 template <typename K, typename V>
166 static node_type * alloc_node( const K& key, const V& val )
168 return cxx_allocator().New( key, val );
171 template <typename K, typename... Args>
172 static node_type * alloc_node( K&& key, Args&&... args )
174 return cxx_allocator().MoveNew( std::forward<K>(key), std::forward<Args>(args)...);
177 static void free_node( node_type * pNode )
179 cxx_allocator().Delete( pNode );
182 struct node_disposer {
183 void operator()( node_type * pNode )
188 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
192 return base_class::m_pHead;
195 head_type& head() const
197 return const_cast<head_type&>( base_class::m_pHead );
203 template <bool IsConst>
204 class iterator_type: protected base_class::template iterator_type<IsConst>
206 typedef typename base_class::template iterator_type<IsConst> iterator_base;
208 iterator_type( head_type const& pNode )
209 : iterator_base( pNode )
212 friend class MichaelKVList;
215 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
216 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
218 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
219 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
224 iterator_type( iterator_type const& src )
225 : iterator_base( src )
228 key_type const& key() const
230 typename iterator_base::value_ptr p = iterator_base::operator ->();
231 assert( p != nullptr );
232 return p->m_Data.first;
235 pair_ptr operator ->() const
237 typename iterator_base::value_ptr p = iterator_base::operator ->();
238 return p ? &(p->m_Data) : nullptr;
241 pair_ref operator *() const
243 typename iterator_base::value_ref p = iterator_base::operator *();
247 value_ref val() const
249 typename iterator_base::value_ptr p = iterator_base::operator ->();
250 assert( p != nullptr );
251 return p->m_Data.second;
255 iterator_type& operator ++()
257 iterator_base::operator ++();
262 bool operator ==(iterator_type<C> const& i ) const
264 return iterator_base::operator ==(i);
267 bool operator !=(iterator_type<C> const& i ) const
269 return iterator_base::operator !=(i);
276 typedef iterator_type<false> iterator;
278 /// Const forward iterator
279 typedef iterator_type<true> const_iterator;
281 /// Returns a forward iterator addressing the first element in a list
283 For empty list \code begin() == end() \endcode
287 return iterator( head() );
290 /// Returns an iterator that addresses the location succeeding the last element in a list
292 Do not use the value returned by <tt>end</tt> function to access any item.
293 Internally, <tt>end</tt> returning value equals to \p nullptr.
295 The returned value can be used only to control reaching the end of the list.
296 For empty list \code begin() == end() \endcode
303 /// Returns a forward const iterator addressing the first element in a list
305 const_iterator begin() const
307 return const_iterator( head() );
309 const_iterator cbegin() const
311 return const_iterator( head() );
315 /// Returns an const iterator that addresses the location succeeding the last element in a list
317 const_iterator end() const
319 return const_iterator();
321 const_iterator cend() const
323 return const_iterator();
328 /// Default constructor
330 Initializes empty list
344 /// Inserts new node with key and default value
346 The function creates a node with \p key and default value, and then inserts the node created into the list.
349 - The \ref key_type should be constructible from value of type \p K.
350 In trivial case, \p K is equal to \ref key_type.
351 - The \ref mapped_type should be default-constructible.
353 The function applies RCU lock internally.
355 Returns \p true if inserting successful, \p false otherwise.
357 template <typename K>
358 bool insert( const K& key )
360 return insert_at( head(), key );
363 /// Inserts new node with a key and a value
365 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
368 - The \ref key_type should be constructible from \p key of type \p K.
369 - The \ref mapped_type should be constructible from \p val of type \p V.
371 The function applies RCU lock internally.
373 Returns \p true if inserting successful, \p false otherwise.
375 template <typename K, typename V>
376 bool insert( const K& key, const V& val )
378 return insert_at( head(), key, val );
381 /// Inserts new node and initialize it by a functor
383 This function inserts new node with key \p key and if inserting is successful then it calls
384 \p func functor with signature
387 void operator()( value_type& item );
391 The argument \p item of user-defined functor \p func is the reference
392 to the list's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
393 User-defined functor \p func should guarantee that during changing item's value no any other changes
394 could be made on this list's item by concurrent threads.
396 The key_type should be constructible from value of type \p K.
398 The function allows to split creating of new item into two part:
399 - create item from \p key;
400 - insert new item into the list;
401 - if inserting is successful, initialize the value of item by calling \p func functor
403 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
404 it is preferable that the initialization should be completed only if inserting is successful.
406 The function applies RCU lock internally.
408 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
410 template <typename K, typename Func>
411 bool insert_with( const K& key, Func func )
413 return insert_with_at( head(), key, func );
416 /// Ensures that the \p key exists in the list
418 The operation performs inserting or changing data with lock-free manner.
420 If the \p key not found in the list, then the new item created from \p key
421 is inserted into the list (note that in this case the \ref key_type should be
422 copy-constructible from type \p K).
423 Otherwise, the functor \p func is called with item found.
424 The functor \p Func may be a function with signature:
426 void func( bool bNew, value_type& item );
431 void operator()( bool bNew, value_type& item );
436 - \p bNew - \p true if the item has been inserted, \p false otherwise
437 - \p item - item of the list
439 The functor may change any fields of the \p item.second that is \ref mapped_type;
440 however, \p func must guarantee that during changing no any other modifications
441 could be made on this item by concurrent threads.
443 The function applies RCU lock internally.
445 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
446 \p second is true if new item has been added or \p false if the item with \p key
447 already is in the list.
449 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
451 template <typename K, typename Func>
452 std::pair<bool, bool> ensure( const K& key, Func f )
454 return ensure_at( head(), key, f );
457 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
459 Returns \p true if inserting successful, \p false otherwise.
461 The function applies RCU lock internally.
463 template <typename K, typename... Args>
464 bool emplace( K&& key, Args&&... args )
466 return emplace_at( head(), std::forward<K>(key), std::forward<Args>(args)... );
469 /// Deletes \p key from the list
470 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase
472 RCU \p synchronize method can be called. RCU should not be locked.
474 Returns \p true if \p key is found and has been deleted, \p false otherwise
476 template <typename K>
477 bool erase( K const& key )
479 return erase_at( head(), key, intrusive_key_comparator() );
482 /// Deletes the item from the list using \p pred predicate for searching
484 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_erase "erase(K const&)"
485 but \p pred is used for key comparing.
486 \p Less functor has the interface like \p std::less.
487 \p pred must imply the same element order as the comparator used for building the list.
489 template <typename K, typename Less>
490 bool erase_with( K const& key, Less pred )
493 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
496 /// Deletes \p key from the list
497 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase_func
498 The function searches an item with key \p key, calls \p f functor
499 and deletes the item. If \p key is not found, the functor is not called.
501 The functor \p Func interface:
504 void operator()(value_type& val) { ... }
508 RCU \p synchronize method can be called. RCU should not be locked.
510 Return \p true if key is found and deleted, \p false otherwise
514 template <typename K, typename Func>
515 bool erase( K const& key, Func f )
517 return erase_at( head(), key, intrusive_key_comparator(), f );
520 /// Deletes the item from the list using \p pred predicate for searching
522 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_erase_func "erase(K const&, Func)"
523 but \p pred is used for key comparing.
524 \p Less functor has the interface like \p std::less.
525 \p pred must imply the same element order as the comparator used for building the list.
527 template <typename K, typename Less, typename Func>
528 bool erase_with( K const& key, Less pred, Func f )
531 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
534 /// Extracts an item from the list
536 @anchor cds_nonintrusive_MichaelKVList_rcu_extract
537 The function searches an item with key equal to \p key in the list,
538 unlinks it from the list, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item found.
539 If \p key is not found the function returns an empty \p exempt_ptr.
541 @note The function does NOT dispose the item found.
542 It just excludes the item from the list and returns a pointer to item found.
543 You shouldn't lock RCU before calling this function.
546 #include <cds/urcu/general_buffered.h>
547 #include <cds/container/michael_kvlist_rcu.h>
549 typedef cds::urcu::gc< general_buffered<> > rcu;
550 typedef cds::container::MichaelKVList< rcu, int, Foo > rcu_michael_list;
552 rcu_michael_list theList;
555 rcu_michael_list::exempt_ptr p;
557 // The RCU should NOT be locked when extract() is called!
558 assert( !rcu::is_locked() );
561 p = theList.extract( 10 );
563 // do something with p
567 // we may safely release extracted pointer here.
568 // release() passes the pointer to RCU reclamation cycle.
572 template <typename K>
573 exempt_ptr extract( K const& key )
575 return exempt_ptr( extract_at( head(), key, intrusive_key_comparator() ));
578 /// Extracts an item from the list using \p pred predicate for searching
580 This function is the analog for \p extract(K const&).
581 The \p pred is a predicate used for key comparing.
582 \p Less has the interface like \p std::less.
583 \p pred must imply the same element order as \ref key_comparator.
585 template <typename K, typename Less>
586 exempt_ptr extract_with( K const& key, Less pred )
589 return exempt_ptr( extract_at( head(), key, typename maker::template less_wrapper<Less>::type() ));
592 /// Finds the key \p key
593 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_val
595 The function searches the item with key equal to \p key
596 and returns \p true if it is found, and \p false otherwise
598 The function makes RCU lock internally.
600 template <typename Q>
601 bool find( Q const& key )
603 return find_at( head(), key, intrusive_key_comparator() );
606 /// Finds the key \p key using \p pred predicate for searching
608 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_val "find(Q const&)"
609 but \p pred is used for key comparing.
610 \p Less functor has the interface like \p std::less.
611 \p pred must imply the same element order as the comparator used for building the list.
613 template <typename Q, typename Less>
614 bool find_with( Q const& key, Less pred )
617 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
620 /// Finds \p key and performs an action with it
621 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_func
622 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
623 The interface of \p Func functor is:
626 void operator()( value_type& item );
629 where \p item is the item found.
631 The functor may change <tt>item.second</tt> that is reference to value of node.
632 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
633 The function does not serialize simultaneous access to the list \p item. If such access is
634 possible you must provide your own synchronization schema to exclude unsafe item modifications.
636 The function makes RCU lock internally.
638 The function returns \p true if \p key is found, \p false otherwise.
640 template <typename Q, typename Func>
641 bool find( Q const& key, Func f )
643 return find_at( head(), key, intrusive_key_comparator(), f );
646 /// Finds the key \p val using \p pred predicate for searching
648 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_func "find(Q const&, Func)"
649 but \p pred is used for key comparing.
650 \p Less functor has the interface like \p std::less.
651 \p pred must imply the same element order as the comparator used for building the list.
653 template <typename Q, typename Less, typename Func>
654 bool find_with( Q const& key, Less pred, Func f )
657 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
660 /// Finds \p key and return the item found
661 /** \anchor cds_nonintrusive_MichaelKVList_rcu_get
662 The function searches the item with \p key and returns the pointer to item found.
663 If \p key is not found it returns an empty \p raw_ptr object.
665 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
667 RCU should be locked before call of this function.
668 Returned item is valid only while RCU is locked:
670 typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, foo, my_traits > ord_list;
673 tyename ord_list::raw_ptr rp;
676 ord_list::rcu_lock lock;
678 rp = theList.get( 5 );
683 // Unlock RCU by rcu_lock destructor
685 // rp can be released at any time after RCU has been unlocked
689 template <typename K>
690 raw_ptr get( K const& key )
692 return get_at( head(), key, intrusive_key_comparator());
695 /// Finds \p key and return the item found
697 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_get "get(K const&)"
698 but \p pred is used for comparing the keys.
700 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
702 \p pred must imply the same element order as the comparator used for building the list.
704 template <typename K, typename Less>
705 raw_ptr get_with( K const& key, Less pred )
708 return get_at( head(), key, typename maker::template less_wrapper<Less>::type() );
711 /// Checks if the list is empty
714 return base_class::empty();
717 /// Returns list's item count
719 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
720 this function always returns 0.
722 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
723 is empty. To check list emptyness use \p empty() method.
727 return base_class::size();
732 Post-condition: the list is empty
741 bool insert_node_at( head_type& refHead, node_type * pNode )
743 assert( pNode != nullptr );
744 scoped_node_ptr p( pNode );
745 if ( base_class::insert_at( refHead, *pNode )) {
752 template <typename K>
753 bool insert_at( head_type& refHead, const K& key )
755 return insert_node_at( refHead, alloc_node( key ));
758 template <typename K, typename V>
759 bool insert_at( head_type& refHead, const K& key, const V& val )
761 return insert_node_at( refHead, alloc_node( key, val ));
764 template <typename K, typename Func>
765 bool insert_with_at( head_type& refHead, const K& key, Func f )
767 scoped_node_ptr pNode( alloc_node( key ));
769 if ( base_class::insert_at( refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); })) {
776 template <typename K, typename... Args>
777 bool emplace_at( head_type& refHead, K&& key, Args&&... args )
779 return insert_node_at( refHead, alloc_node( std::forward<K>(key), std::forward<Args>(args)... ));
782 template <typename K, typename Func>
783 std::pair<bool, bool> ensure_at( head_type& refHead, const K& key, Func f )
785 scoped_node_ptr pNode( alloc_node( key ));
787 std::pair<bool, bool> ret = base_class::ensure_at( refHead, *pNode,
788 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); });
789 if ( ret.first && ret.second )
795 template <typename K, typename Compare>
796 bool erase_at( head_type& refHead, K const& key, Compare cmp )
798 return base_class::erase_at( refHead, key, cmp );
801 template <typename K, typename Compare, typename Func>
802 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
804 return base_class::erase_at( refHead, key, cmp, [&f]( node_type const & node ){ f( const_cast<value_type&>(node.m_Data)); });
807 template <typename K, typename Compare>
808 node_type * extract_at( head_type& refHead, K const& key, Compare cmp )
810 return base_class::extract_at( refHead, key, cmp );
813 template <typename K, typename Compare>
814 bool find_at( head_type& refHead, K const& key, Compare cmp )
816 return base_class::find_at( refHead, key, cmp, [](node_type&, K const&) {} );
819 template <typename K, typename Compare, typename Func>
820 bool find_at( head_type& refHead, K& key, Compare cmp, Func f )
822 return base_class::find_at( refHead, key, cmp, [&f](node_type& node, K const&){ f( node.m_Data ); });
825 template <typename K, typename Compare>
826 raw_ptr get_at( head_type& refHead, K const& val, Compare cmp )
828 return raw_ptr( base_class::get_at( refHead, val, cmp ));
834 }} // namespace cds::container
836 #endif // #ifndef CDSLIB_CONTAINER_MICHAEL_KVLIST_RCU_H