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 template <typename K, typename Func>
387 bool insert_key( const K& key, Func func )
389 return insert_key_at( head(), key, func );
392 /// Ensures that the \p key exists in the list
394 The operation performs inserting or changing data with lock-free manner.
396 If the \p key not found in the list, then the new item created from \p key
397 is inserted into the list (note that in this case the \ref key_type should be
398 copy-constructible from type \p K).
399 Otherwise, the functor \p func is called with item found.
400 The functor \p Func may be a function with signature:
402 void func( bool bNew, value_type& item );
407 void operator()( bool bNew, value_type& item );
412 - \p bNew - \p true if the item has been inserted, \p false otherwise
413 - \p item - item of the list
415 The functor may change any fields of the \p item.second that is \ref mapped_type;
416 however, \p func must guarantee that during changing no any other modifications
417 could be made on this item by concurrent threads.
419 You may pass \p func argument by reference using \p std::ref
421 The function makes RCU lock internally.
423 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
424 \p second is true if new item has been added or \p false if the item with \p key
425 already is in the list.
427 template <typename K, typename Func>
428 std::pair<bool, bool> ensure( const K& key, Func f )
430 return ensure_at( head(), key, f );
433 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
435 Returns \p true if inserting successful, \p false otherwise.
437 The function makes RCU lock internally.
439 template <typename K, typename... Args>
440 bool emplace( K&& key, Args&&... args )
442 return emplace_at( head(), std::forward<K>(key), std::forward<Args>(args)... );
445 /// Deletes \p key from the list
446 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase
448 RCU \p synchronize method can be called. RCU should not be locked.
450 Returns \p true if \p key is found and has been deleted, \p false otherwise
452 template <typename K>
453 bool erase( K const& key )
455 return erase_at( head(), key, intrusive_key_comparator() );
458 /// Deletes the item from the list using \p pred predicate for searching
460 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_erase "erase(K const&)"
461 but \p pred is used for key comparing.
462 \p Less functor has the interface like \p std::less.
463 \p pred must imply the same element order as the comparator used for building the list.
465 template <typename K, typename Less>
466 bool erase_with( K const& key, Less pred )
468 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
471 /// Deletes \p key from the list
472 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase_func
473 The function searches an item with key \p key, calls \p f functor
474 and deletes the item. If \p key is not found, the functor is not called.
476 The functor \p Func interface:
479 void operator()(value_type& val) { ... }
482 The functor may be passed by reference with <tt>boost:ref</tt>
484 RCU \p synchronize method can be called. RCU should not be locked.
486 Return \p true if key is found and deleted, \p false otherwise
490 template <typename K, typename Func>
491 bool erase( K const& key, Func f )
493 return erase_at( head(), key, intrusive_key_comparator(), f );
496 /// Deletes the item from the list using \p pred predicate for searching
498 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_erase_func "erase(K const&, Func)"
499 but \p pred is used for key comparing.
500 \p Less functor has the interface like \p std::less.
501 \p pred must imply the same element order as the comparator used for building the list.
503 template <typename K, typename Less, typename Func>
504 bool erase_with( K const& key, Less pred, Func f )
506 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
509 /// Extracts an item from the list
511 @anchor cds_nonintrusive_MichaelKVList_rcu_extract
512 The function searches an item with key equal to \p key in the list,
513 unlinks it from the list, and returns pointer to an item found in \p dest argument.
514 If \p key is not found the function returns \p false.
516 @note The function does NOT call RCU read-side lock or synchronization,
517 and does NOT dispose the item found. It just excludes the item from the list
518 and returns a pointer to item found.
519 You should lock RCU before calling this function.
522 #include <cds/urcu/general_buffered.h>
523 #include <cds/container/michael_kvlist_rcu.h>
525 typedef cds::urcu::gc< general_buffered<> > rcu;
526 typedef cds::container::MichaelKVList< rcu, int, Foo > rcu_michael_list;
528 rcu_michael_list theList;
531 rcu_michael_list::exempt_ptr p;
533 // first, we should lock RCU
534 rcu_michael_list::rcu_lock sl;
536 // Now, you can apply extract function
537 // Note that you must not delete the item found inside the RCU lock
538 if ( theList.extract( p, 10 )) {
539 // do something with p
543 // Outside RCU lock section we may safely release extracted pointer.
544 // release() passes the pointer to RCU reclamation cycle.
548 template <typename K>
549 bool extract( exempt_ptr& dest, K const& key )
551 dest = extract_at( head(), key, intrusive_key_comparator() );
552 return !dest.empty();
555 /// Extracts an item from the list using \p pred predicate for searching
557 This function is the analog for \ref cds_nonintrusive_MichaelKVList_rcu_extract "extract(exempt_ptr&, K const&)".
558 The \p pred is a predicate used for key comparing.
559 \p Less has the interface like \p std::less.
560 \p pred must imply the same element order as \ref key_comparator.
562 template <typename K, typename Less>
563 bool extract_with( exempt_ptr& dest, K const& key, Less pred )
565 dest = extract_at( head(), key, typename maker::template less_wrapper<Less>::type() );
566 return !dest.empty();
569 /// Finds the key \p key
570 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_val
572 The function searches the item with key equal to \p key
573 and returns \p true if it is found, and \p false otherwise
575 The function makes RCU lock internally.
577 template <typename Q>
578 bool find( Q const& key ) const
580 return find_at( head(), key, intrusive_key_comparator() );
583 /// Finds the key \p key using \p pred predicate for searching
585 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_val "find(Q const&)"
586 but \p pred is used for key comparing.
587 \p Less functor has the interface like \p std::less.
588 \p pred must imply the same element order as the comparator used for building the list.
590 template <typename Q, typename Less>
591 bool find_with( Q const& key, Less pred ) const
593 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
596 /// Finds \p key and performs an action with it
597 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_func
598 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
599 The interface of \p Func functor is:
602 void operator()( value_type& item );
605 where \p item is the item found.
607 The functor may change <tt>item.second</tt> that is reference to value of node.
608 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
609 The function does not serialize simultaneous access to the list \p item. If such access is
610 possible you must provide your own synchronization schema to exclude unsafe item modifications.
612 The function makes RCU lock internally.
614 The function returns \p true if \p key is found, \p false otherwise.
616 template <typename Q, typename Func>
617 bool find( Q const& key, Func f ) const
619 return find_at( head(), key, intrusive_key_comparator(), f );
622 /// Finds the key \p val using \p pred predicate for searching
624 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_func "find(Q const&, Func)"
625 but \p pred is used for key comparing.
626 \p Less functor has the interface like \p std::less.
627 \p pred must imply the same element order as the comparator used for building the list.
629 template <typename Q, typename Less, typename Func>
630 bool find_with( Q const& key, Less pred, Func f ) const
632 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
635 /// Finds \p key and return the item found
636 /** \anchor cds_nonintrusive_MichaelKVList_rcu_get
637 The function searches the item with \p key and returns the pointer to item found.
638 If \p key is not found it returns \p nullptr.
640 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
642 RCU should be locked before call of this function.
643 Returned item is valid only while RCU is locked:
645 typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, foo, my_traits > ord_list;
650 ord_list::rcu_lock lock;
652 ord_list::value_type * pVal = theList.get( 5 );
657 // Unlock RCU by rcu_lock destructor
658 // pVal can be freed at any time after RCU has been unlocked
662 template <typename K>
663 value_type * get( K const& key ) const
665 return get_at( head(), key, intrusive_key_comparator());
668 /// Finds \p key and return the item found
670 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_get "get(K const&)"
671 but \p pred is used for comparing the keys.
673 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
675 \p pred must imply the same element order as the comparator used for building the list.
677 template <typename K, typename Less>
678 value_type * get_with( K const& key, Less pred ) const
680 return get_at( head(), key, typename maker::template less_wrapper<Less>::type() );
683 /// Checks if the list is empty
686 return base_class::empty();
689 /// Returns list's item count
691 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
692 this function always returns 0.
694 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
695 is empty. To check list emptyness use \p empty() method.
699 return base_class::size();
704 Post-condition: the list is empty
713 bool insert_node_at( head_type& refHead, node_type * pNode )
715 assert( pNode != nullptr );
716 scoped_node_ptr p( pNode );
717 if ( base_class::insert_at( refHead, *pNode )) {
724 template <typename K>
725 bool insert_at( head_type& refHead, const K& key )
727 return insert_node_at( refHead, alloc_node( key ));
730 template <typename K, typename V>
731 bool insert_at( head_type& refHead, const K& key, const V& val )
733 return insert_node_at( refHead, alloc_node( key, val ));
736 template <typename K, typename Func>
737 bool insert_key_at( head_type& refHead, const K& key, Func f )
739 scoped_node_ptr pNode( alloc_node( key ));
741 if ( base_class::insert_at( refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); })) {
748 template <typename K, typename... Args>
749 bool emplace_at( head_type& refHead, K&& key, Args&&... args )
751 return insert_node_at( refHead, alloc_node( std::forward<K>(key), std::forward<Args>(args)... ));
754 template <typename K, typename Func>
755 std::pair<bool, bool> ensure_at( head_type& refHead, const K& key, Func f )
757 scoped_node_ptr pNode( alloc_node( key ));
759 std::pair<bool, bool> ret = base_class::ensure_at( refHead, *pNode,
760 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); });
761 if ( ret.first && ret.second )
767 template <typename K, typename Compare>
768 bool erase_at( head_type& refHead, K const& key, Compare cmp )
770 return base_class::erase_at( refHead, key, cmp );
773 template <typename K, typename Compare, typename Func>
774 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
776 return base_class::erase_at( refHead, key, cmp, [&f]( node_type const & node ){ f( const_cast<value_type&>(node.m_Data)); });
779 template <typename K, typename Compare>
780 node_type * extract_at( head_type& refHead, K const& key, Compare cmp )
782 return base_class::extract_at( refHead, key, cmp );
785 template <typename K, typename Compare>
786 bool find_at( head_type& refHead, K const& key, Compare cmp ) const
788 return base_class::find_at( refHead, key, cmp, [](node_type&, K const&) {} );
791 template <typename K, typename Compare, typename Func>
792 bool find_at( head_type& refHead, K& key, Compare cmp, Func f ) const
794 return base_class::find_at( refHead, key, cmp, [&f](node_type& node, K const&){ f( node.m_Data ); });
797 template <typename K, typename Compare>
798 value_type * get_at( head_type& refHead, K const& val, Compare cmp ) const
800 node_type * pNode = base_class::get_at( refHead, val, cmp );
801 return pNode ? &pNode->m_Data : nullptr;
807 }} // namespace cds::container
809 #endif // #ifndef __CDS_CONTAINER_MICHAEL_KVLIST_RCU_H