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 #ifdef CDS_DOXYGEN_INVOKED
96 typedef Key key_type ; ///< Key type
97 typedef Value mapped_type ; ///< Type of value stored in the list
98 typedef std::pair<key_type const, mapped_type> value_type ; ///< key/value pair stored in the list
100 typedef typename maker::key_type key_type;
101 typedef typename maker::value_type mapped_type;
102 typedef typename maker::pair_type value_type;
104 typename Traits traits; ///< List traits
106 typedef typename base_class::gc gc ; ///< Garbage collector used
107 typedef typename base_class::back_off back_off ; ///< Back-off strategy used
108 typedef typename maker::allocator_type allocator_type; ///< Allocator type used for allocate/deallocate the nodes
109 typedef typename base_class::item_counter item_counter ; ///< Item counting policy used
110 typedef typename maker::key_comparator key_comparator; ///< key comparison functor
111 typedef typename base_class::memory_model memory_model ; ///< Memory ordering. See cds::opt::memory_model option
112 typedef typename base_class::rcu_check_deadlock rcu_check_deadlock ; ///< RCU deadlock checking policy
114 typedef typename gc::scoped_lock rcu_lock ; ///< RCU scoped lock
115 static CDS_CONSTEXPR const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal; ///< Group of \p extract_xxx functions require external locking
119 typedef typename base_class::value_type node_type;
120 typedef typename maker::cxx_allocator cxx_allocator;
121 typedef typename maker::node_deallocator node_deallocator;
122 typedef typename maker::intrusive_traits::compare intrusive_key_comparator;
124 typedef typename base_class::atomic_node_ptr head_type;
128 /// pointer to extracted node
129 typedef cds::urcu::exempt_ptr< gc, node_type, value_type, typename maker::intrusive_traits::disposer,
130 cds::urcu::details::conventional_exempt_pair_cast<node_type, value_type>
135 template <typename K>
136 static node_type * alloc_node(const K& key)
138 return cxx_allocator().New( key );
141 template <typename K, typename V>
142 static node_type * alloc_node( const K& key, const V& val )
144 return cxx_allocator().New( key, val );
147 template <typename K, typename... Args>
148 static node_type * alloc_node( K&& key, Args&&... args )
150 return cxx_allocator().MoveNew( std::forward<K>(key), std::forward<Args>(args)...);
153 static void free_node( node_type * pNode )
155 cxx_allocator().Delete( pNode );
158 struct node_disposer {
159 void operator()( node_type * pNode )
164 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
168 return base_class::m_pHead;
171 head_type& head() const
173 return const_cast<head_type&>( base_class::m_pHead );
179 template <bool IsConst>
180 class iterator_type: protected base_class::template iterator_type<IsConst>
182 typedef typename base_class::template iterator_type<IsConst> iterator_base;
184 iterator_type( head_type const& pNode )
185 : iterator_base( pNode )
188 friend class MichaelKVList;
191 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
192 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
194 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
195 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
200 iterator_type( iterator_type const& src )
201 : iterator_base( src )
204 key_type const& key() const
206 typename iterator_base::value_ptr p = iterator_base::operator ->();
207 assert( p != nullptr );
208 return p->m_Data.first;
211 pair_ptr operator ->() const
213 typename iterator_base::value_ptr p = iterator_base::operator ->();
214 return p ? &(p->m_Data) : nullptr;
217 pair_ref operator *() const
219 typename iterator_base::value_ref p = iterator_base::operator *();
223 value_ref val() const
225 typename iterator_base::value_ptr p = iterator_base::operator ->();
226 assert( p != nullptr );
227 return p->m_Data.second;
231 iterator_type& operator ++()
233 iterator_base::operator ++();
238 bool operator ==(iterator_type<C> const& i ) const
240 return iterator_base::operator ==(i);
243 bool operator !=(iterator_type<C> const& i ) const
245 return iterator_base::operator !=(i);
252 typedef iterator_type<false> iterator;
254 /// Const forward iterator
255 typedef iterator_type<true> const_iterator;
257 /// Returns a forward iterator addressing the first element in a list
259 For empty list \code begin() == end() \endcode
263 return iterator( head() );
266 /// Returns an iterator that addresses the location succeeding the last element in a list
268 Do not use the value returned by <tt>end</tt> function to access any item.
269 Internally, <tt>end</tt> returning value equals to \p nullptr.
271 The returned value can be used only to control reaching the end of the list.
272 For empty list \code begin() == end() \endcode
279 /// Returns a forward const iterator addressing the first element in a list
281 const_iterator begin() const
283 return const_iterator( head() );
285 const_iterator cbegin()
287 return const_iterator( head() );
291 /// Returns an const iterator that addresses the location succeeding the last element in a list
293 const_iterator end() const
295 return const_iterator();
297 const_iterator cend()
299 return const_iterator();
304 /// Default constructor
306 Initializes empty list
320 /// Inserts new node with key and default value
322 The function creates a node with \p key and default value, and then inserts the node created into the list.
325 - The \ref key_type should be constructible from value of type \p K.
326 In trivial case, \p K is equal to \ref key_type.
327 - The \ref mapped_type should be default-constructible.
329 The function makes RCU lock internally.
331 Returns \p true if inserting successful, \p false otherwise.
333 template <typename K>
334 bool insert( const K& key )
336 return insert_at( head(), key );
339 /// Inserts new node with a key and a value
341 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
344 - The \ref key_type should be constructible from \p key of type \p K.
345 - The \ref mapped_type should be constructible from \p val of type \p V.
347 The function makes RCU lock internally.
349 Returns \p true if inserting successful, \p false otherwise.
351 template <typename K, typename V>
352 bool insert( const K& key, const V& val )
354 return insert_at( head(), key, val );
357 /// Inserts new node and initialize it by a functor
359 This function inserts new node with key \p key and if inserting is successful then it calls
360 \p func functor with signature
363 void operator()( value_type& item );
367 The argument \p item of user-defined functor \p func is the reference
368 to the list's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
369 User-defined functor \p func should guarantee that during changing item's value no any other changes
370 could be made on this list's item by concurrent threads.
371 The user-defined functor can be passed by reference using \p std::ref
372 and it is called only if inserting is successful.
374 The key_type should be constructible from value of type \p K.
376 The function allows to split creating of new item into two part:
377 - create item from \p key;
378 - insert new item into the list;
379 - if inserting is successful, initialize the value of item by calling \p func functor
381 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
382 it is preferable that the initialization should be completed only if inserting is successful.
384 The function makes RCU lock internally.
386 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
388 template <typename K, typename Func>
389 bool insert_key( const K& key, Func func )
391 return insert_key_at( head(), key, func );
394 /// Ensures that the \p key exists in the list
396 The operation performs inserting or changing data with lock-free manner.
398 If the \p key not found in the list, then the new item created from \p key
399 is inserted into the list (note that in this case the \ref key_type should be
400 copy-constructible from type \p K).
401 Otherwise, the functor \p func is called with item found.
402 The functor \p Func may be a function with signature:
404 void func( bool bNew, value_type& item );
409 void operator()( bool bNew, value_type& item );
414 - \p bNew - \p true if the item has been inserted, \p false otherwise
415 - \p item - item of the list
417 The functor may change any fields of the \p item.second that is \ref mapped_type;
418 however, \p func must guarantee that during changing no any other modifications
419 could be made on this item by concurrent threads.
421 You may pass \p func argument by reference using \p std::ref
423 The function makes RCU lock internally.
425 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
426 \p second is true if new item has been added or \p false if the item with \p key
427 already is in the list.
429 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
431 template <typename K, typename Func>
432 std::pair<bool, bool> ensure( const K& key, Func f )
434 return ensure_at( head(), key, f );
437 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
439 Returns \p true if inserting successful, \p false otherwise.
441 The function makes RCU lock internally.
443 template <typename K, typename... Args>
444 bool emplace( K&& key, Args&&... args )
446 return emplace_at( head(), std::forward<K>(key), std::forward<Args>(args)... );
449 /// Deletes \p key from the list
450 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase
452 RCU \p synchronize method can be called. RCU should not be locked.
454 Returns \p true if \p key is found and has been deleted, \p false otherwise
456 template <typename K>
457 bool erase( K const& key )
459 return erase_at( head(), key, intrusive_key_comparator() );
462 /// Deletes the item from the list using \p pred predicate for searching
464 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_erase "erase(K const&)"
465 but \p pred is used for key comparing.
466 \p Less functor has the interface like \p std::less.
467 \p pred must imply the same element order as the comparator used for building the list.
469 template <typename K, typename Less>
470 bool erase_with( K const& key, Less pred )
472 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
475 /// Deletes \p key from the list
476 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase_func
477 The function searches an item with key \p key, calls \p f functor
478 and deletes the item. If \p key is not found, the functor is not called.
480 The functor \p Func interface:
483 void operator()(value_type& val) { ... }
486 The functor may be passed by reference with <tt>boost:ref</tt>
488 RCU \p synchronize method can be called. RCU should not be locked.
490 Return \p true if key is found and deleted, \p false otherwise
494 template <typename K, typename Func>
495 bool erase( K const& key, Func f )
497 return erase_at( head(), key, intrusive_key_comparator(), f );
500 /// Deletes the item from the list using \p pred predicate for searching
502 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_erase_func "erase(K const&, Func)"
503 but \p pred is used for key comparing.
504 \p Less functor has the interface like \p std::less.
505 \p pred must imply the same element order as the comparator used for building the list.
507 template <typename K, typename Less, typename Func>
508 bool erase_with( K const& key, Less pred, Func f )
510 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
513 /// Extracts an item from the list
515 @anchor cds_nonintrusive_MichaelKVList_rcu_extract
516 The function searches an item with key equal to \p key in the list,
517 unlinks it from the list, and returns pointer to an item found in \p dest argument.
518 If \p key is not found the function returns \p false.
520 @note The function does NOT call RCU read-side lock or synchronization,
521 and does NOT dispose the item found. It just excludes the item from the list
522 and returns a pointer to item found.
523 You should lock RCU before calling this function.
526 #include <cds/urcu/general_buffered.h>
527 #include <cds/container/michael_kvlist_rcu.h>
529 typedef cds::urcu::gc< general_buffered<> > rcu;
530 typedef cds::container::MichaelKVList< rcu, int, Foo > rcu_michael_list;
532 rcu_michael_list theList;
535 rcu_michael_list::exempt_ptr p;
537 // first, we should lock RCU
538 rcu_michael_list::rcu_lock sl;
540 // Now, you can apply extract function
541 // Note that you must not delete the item found inside the RCU lock
542 if ( theList.extract( p, 10 )) {
543 // do something with p
547 // Outside RCU lock section we may safely release extracted pointer.
548 // release() passes the pointer to RCU reclamation cycle.
552 template <typename K>
553 bool extract( exempt_ptr& dest, K const& key )
555 dest = extract_at( head(), key, intrusive_key_comparator() );
556 return !dest.empty();
559 /// Extracts an item from the list using \p pred predicate for searching
561 This function is the analog for \ref cds_nonintrusive_MichaelKVList_rcu_extract "extract(exempt_ptr&, K const&)".
562 The \p pred is a predicate used for key comparing.
563 \p Less has the interface like \p std::less.
564 \p pred must imply the same element order as \ref key_comparator.
566 template <typename K, typename Less>
567 bool extract_with( exempt_ptr& dest, K const& key, Less pred )
569 dest = extract_at( head(), key, typename maker::template less_wrapper<Less>::type() );
570 return !dest.empty();
573 /// Finds the key \p key
574 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_val
576 The function searches the item with key equal to \p key
577 and returns \p true if it is found, and \p false otherwise
579 The function makes RCU lock internally.
581 template <typename Q>
582 bool find( Q const& key ) const
584 return find_at( head(), key, intrusive_key_comparator() );
587 /// Finds the key \p key using \p pred predicate for searching
589 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_val "find(Q const&)"
590 but \p pred is used for key comparing.
591 \p Less functor has the interface like \p std::less.
592 \p pred must imply the same element order as the comparator used for building the list.
594 template <typename Q, typename Less>
595 bool find_with( Q const& key, Less pred ) const
597 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
600 /// Finds \p key and performs an action with it
601 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_func
602 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
603 The interface of \p Func functor is:
606 void operator()( value_type& item );
609 where \p item is the item found.
611 The functor may change <tt>item.second</tt> that is reference to value of node.
612 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
613 The function does not serialize simultaneous access to the list \p item. If such access is
614 possible you must provide your own synchronization schema to exclude unsafe item modifications.
616 The function makes RCU lock internally.
618 The function returns \p true if \p key is found, \p false otherwise.
620 template <typename Q, typename Func>
621 bool find( Q const& key, Func f ) const
623 return find_at( head(), key, intrusive_key_comparator(), f );
626 /// Finds the key \p val using \p pred predicate for searching
628 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_func "find(Q const&, Func)"
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 template <typename Q, typename Less, typename Func>
634 bool find_with( Q const& key, Less pred, Func f ) const
636 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
639 /// Finds \p key and return the item found
640 /** \anchor cds_nonintrusive_MichaelKVList_rcu_get
641 The function searches the item with \p key and returns the pointer to item found.
642 If \p key is not found it returns \p nullptr.
644 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
646 RCU should be locked before call of this function.
647 Returned item is valid only while RCU is locked:
649 typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, foo, my_traits > ord_list;
654 ord_list::rcu_lock lock;
656 ord_list::value_type * pVal = theList.get( 5 );
661 // Unlock RCU by rcu_lock destructor
662 // pVal can be freed at any time after RCU has been unlocked
666 template <typename K>
667 value_type * get( K const& key ) const
669 return get_at( head(), key, intrusive_key_comparator());
672 /// Finds \p key and return the item found
674 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_get "get(K const&)"
675 but \p pred is used for comparing the keys.
677 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
679 \p pred must imply the same element order as the comparator used for building the list.
681 template <typename K, typename Less>
682 value_type * get_with( K const& key, Less pred ) const
684 return get_at( head(), key, typename maker::template less_wrapper<Less>::type() );
687 /// Checks if the list is empty
690 return base_class::empty();
693 /// Returns list's item count
695 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
696 this function always returns 0.
698 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
699 is empty. To check list emptyness use \p empty() method.
703 return base_class::size();
708 Post-condition: the list is empty
717 bool insert_node_at( head_type& refHead, node_type * pNode )
719 assert( pNode != nullptr );
720 scoped_node_ptr p( pNode );
721 if ( base_class::insert_at( refHead, *pNode )) {
728 template <typename K>
729 bool insert_at( head_type& refHead, const K& key )
731 return insert_node_at( refHead, alloc_node( key ));
734 template <typename K, typename V>
735 bool insert_at( head_type& refHead, const K& key, const V& val )
737 return insert_node_at( refHead, alloc_node( key, val ));
740 template <typename K, typename Func>
741 bool insert_key_at( head_type& refHead, const K& key, Func f )
743 scoped_node_ptr pNode( alloc_node( key ));
745 if ( base_class::insert_at( refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); })) {
752 template <typename K, typename... Args>
753 bool emplace_at( head_type& refHead, K&& key, Args&&... args )
755 return insert_node_at( refHead, alloc_node( std::forward<K>(key), std::forward<Args>(args)... ));
758 template <typename K, typename Func>
759 std::pair<bool, bool> ensure_at( head_type& refHead, const K& key, Func f )
761 scoped_node_ptr pNode( alloc_node( key ));
763 std::pair<bool, bool> ret = base_class::ensure_at( refHead, *pNode,
764 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); });
765 if ( ret.first && ret.second )
771 template <typename K, typename Compare>
772 bool erase_at( head_type& refHead, K const& key, Compare cmp )
774 return base_class::erase_at( refHead, key, cmp );
777 template <typename K, typename Compare, typename Func>
778 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
780 return base_class::erase_at( refHead, key, cmp, [&f]( node_type const & node ){ f( const_cast<value_type&>(node.m_Data)); });
783 template <typename K, typename Compare>
784 node_type * extract_at( head_type& refHead, K const& key, Compare cmp )
786 return base_class::extract_at( refHead, key, cmp );
789 template <typename K, typename Compare>
790 bool find_at( head_type& refHead, K const& key, Compare cmp ) const
792 return base_class::find_at( refHead, key, cmp, [](node_type&, K const&) {} );
795 template <typename K, typename Compare, typename Func>
796 bool find_at( head_type& refHead, K& key, Compare cmp, Func f ) const
798 return base_class::find_at( refHead, key, cmp, [&f](node_type& node, K const&){ f( node.m_Data ); });
801 template <typename K, typename Compare>
802 value_type * get_at( head_type& refHead, K const& val, Compare cmp ) const
804 node_type * pNode = base_class::get_at( refHead, val, cmp );
805 return pNode ? &pNode->m_Data : nullptr;
811 }} // namespace cds::container
813 #endif // #ifndef __CDS_CONTAINER_MICHAEL_KVLIST_RCU_H