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 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>
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() const
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() const
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.
373 The key_type should be constructible from value of type \p K.
375 The function allows to split creating of new item into two part:
376 - create item from \p key;
377 - insert new item into the list;
378 - if inserting is successful, initialize the value of item by calling \p func functor
380 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
381 it is preferable that the initialization should be completed only if inserting is successful.
383 The function makes RCU lock internally.
385 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
387 template <typename K, typename Func>
388 bool insert_key( const K& key, Func func )
390 return insert_key_at( head(), key, func );
393 /// Ensures that the \p key exists in the list
395 The operation performs inserting or changing data with lock-free manner.
397 If the \p key not found in the list, then the new item created from \p key
398 is inserted into the list (note that in this case the \ref key_type should be
399 copy-constructible from type \p K).
400 Otherwise, the functor \p func is called with item found.
401 The functor \p Func may be a function with signature:
403 void func( bool bNew, value_type& item );
408 void operator()( bool bNew, value_type& item );
413 - \p bNew - \p true if the item has been inserted, \p false otherwise
414 - \p item - item of the list
416 The functor may change any fields of the \p item.second that is \ref mapped_type;
417 however, \p func must guarantee that during changing no any other modifications
418 could be made on this item by concurrent threads.
420 The function makes RCU lock internally.
422 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
423 \p second is true if new item has been added or \p false if the item with \p key
424 already is in the list.
426 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
428 template <typename K, typename Func>
429 std::pair<bool, bool> ensure( const K& key, Func f )
431 return ensure_at( head(), key, f );
434 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
436 Returns \p true if inserting successful, \p false otherwise.
438 The function makes RCU lock internally.
440 template <typename K, typename... Args>
441 bool emplace( K&& key, Args&&... args )
443 return emplace_at( head(), std::forward<K>(key), std::forward<Args>(args)... );
446 /// Deletes \p key from the list
447 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase
449 RCU \p synchronize method can be called. RCU should not be locked.
451 Returns \p true if \p key is found and has been deleted, \p false otherwise
453 template <typename K>
454 bool erase( K const& key )
456 return erase_at( head(), key, intrusive_key_comparator() );
459 /// Deletes the item from the list using \p pred predicate for searching
461 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_erase "erase(K const&)"
462 but \p pred is used for key comparing.
463 \p Less functor has the interface like \p std::less.
464 \p pred must imply the same element order as the comparator used for building the list.
466 template <typename K, typename Less>
467 bool erase_with( K const& key, Less pred )
469 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
472 /// Deletes \p key from the list
473 /** \anchor cds_nonintrusive_MichaelKVList_rcu_erase_func
474 The function searches an item with key \p key, calls \p f functor
475 and deletes the item. If \p key is not found, the functor is not called.
477 The functor \p Func interface:
480 void operator()(value_type& val) { ... }
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 \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item found.
514 If \p key is not found the function returns an empty \p exempt_ptr.
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 p = theList.extract( 10 );
540 // do something with p
544 // Outside RCU lock section we may safely release extracted pointer.
545 // release() passes the pointer to RCU reclamation cycle.
549 template <typename K>
550 exempt_ptr extract( K const& key )
552 return exempt_ptr( extract_at( head(), key, intrusive_key_comparator() ));
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 exempt_ptr extract_with( K const& key, Less pred )
565 return exempt_ptr( extract_at( head(), key, typename maker::template less_wrapper<Less>::type() ));
568 /// Finds the key \p key
569 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_val
571 The function searches the item with key equal to \p key
572 and returns \p true if it is found, and \p false otherwise
574 The function makes RCU lock internally.
576 template <typename Q>
577 bool find( Q const& key ) const
579 return find_at( head(), key, intrusive_key_comparator() );
582 /// Finds the key \p key using \p pred predicate for searching
584 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_val "find(Q const&)"
585 but \p pred is used for key comparing.
586 \p Less functor has the interface like \p std::less.
587 \p pred must imply the same element order as the comparator used for building the list.
589 template <typename Q, typename Less>
590 bool find_with( Q const& key, Less pred ) const
592 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
595 /// Finds \p key and performs an action with it
596 /** \anchor cds_nonintrusive_MichaelKVList_rcu_find_func
597 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
598 The interface of \p Func functor is:
601 void operator()( value_type& item );
604 where \p item is the item found.
606 The functor may change <tt>item.second</tt> that is reference to value of node.
607 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
608 The function does not serialize simultaneous access to the list \p item. If such access is
609 possible you must provide your own synchronization schema to exclude unsafe item modifications.
611 The function makes RCU lock internally.
613 The function returns \p true if \p key is found, \p false otherwise.
615 template <typename Q, typename Func>
616 bool find( Q const& key, Func f ) const
618 return find_at( head(), key, intrusive_key_comparator(), f );
621 /// Finds the key \p val using \p pred predicate for searching
623 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_find_func "find(Q const&, Func)"
624 but \p pred is used for key comparing.
625 \p Less functor has the interface like \p std::less.
626 \p pred must imply the same element order as the comparator used for building the list.
628 template <typename Q, typename Less, typename Func>
629 bool find_with( Q const& key, Less pred, Func f ) const
631 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
634 /// Finds \p key and return the item found
635 /** \anchor cds_nonintrusive_MichaelKVList_rcu_get
636 The function searches the item with \p key and returns the pointer to item found.
637 If \p key is not found it returns \p nullptr.
639 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
641 RCU should be locked before call of this function.
642 Returned item is valid only while RCU is locked:
644 typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, foo, my_traits > ord_list;
649 ord_list::rcu_lock lock;
651 ord_list::value_type * pVal = theList.get( 5 );
656 // Unlock RCU by rcu_lock destructor
657 // pVal can be freed at any time after RCU has been unlocked
661 template <typename K>
662 value_type * get( K const& key ) const
664 return get_at( head(), key, intrusive_key_comparator());
667 /// Finds \p key and return the item found
669 The function is an analog of \ref cds_nonintrusive_MichaelKVList_rcu_get "get(K const&)"
670 but \p pred is used for comparing the keys.
672 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
674 \p pred must imply the same element order as the comparator used for building the list.
676 template <typename K, typename Less>
677 value_type * get_with( K const& key, Less pred ) const
679 return get_at( head(), key, typename maker::template less_wrapper<Less>::type() );
682 /// Checks if the list is empty
685 return base_class::empty();
688 /// Returns list's item count
690 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
691 this function always returns 0.
693 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
694 is empty. To check list emptyness use \p empty() method.
698 return base_class::size();
703 Post-condition: the list is empty
712 bool insert_node_at( head_type& refHead, node_type * pNode )
714 assert( pNode != nullptr );
715 scoped_node_ptr p( pNode );
716 if ( base_class::insert_at( refHead, *pNode )) {
723 template <typename K>
724 bool insert_at( head_type& refHead, const K& key )
726 return insert_node_at( refHead, alloc_node( key ));
729 template <typename K, typename V>
730 bool insert_at( head_type& refHead, const K& key, const V& val )
732 return insert_node_at( refHead, alloc_node( key, val ));
735 template <typename K, typename Func>
736 bool insert_key_at( head_type& refHead, const K& key, Func f )
738 scoped_node_ptr pNode( alloc_node( key ));
740 if ( base_class::insert_at( refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); })) {
747 template <typename K, typename... Args>
748 bool emplace_at( head_type& refHead, K&& key, Args&&... args )
750 return insert_node_at( refHead, alloc_node( std::forward<K>(key), std::forward<Args>(args)... ));
753 template <typename K, typename Func>
754 std::pair<bool, bool> ensure_at( head_type& refHead, const K& key, Func f )
756 scoped_node_ptr pNode( alloc_node( key ));
758 std::pair<bool, bool> ret = base_class::ensure_at( refHead, *pNode,
759 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); });
760 if ( ret.first && ret.second )
766 template <typename K, typename Compare>
767 bool erase_at( head_type& refHead, K const& key, Compare cmp )
769 return base_class::erase_at( refHead, key, cmp );
772 template <typename K, typename Compare, typename Func>
773 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
775 return base_class::erase_at( refHead, key, cmp, [&f]( node_type const & node ){ f( const_cast<value_type&>(node.m_Data)); });
778 template <typename K, typename Compare>
779 node_type * extract_at( head_type& refHead, K const& key, Compare cmp )
781 return base_class::extract_at( refHead, key, cmp );
784 template <typename K, typename Compare>
785 bool find_at( head_type& refHead, K const& key, Compare cmp ) const
787 return base_class::find_at( refHead, key, cmp, [](node_type&, K const&) {} );
790 template <typename K, typename Compare, typename Func>
791 bool find_at( head_type& refHead, K& key, Compare cmp, Func f ) const
793 return base_class::find_at( refHead, key, cmp, [&f](node_type& node, K const&){ f( node.m_Data ); });
796 template <typename K, typename Compare>
797 value_type * get_at( head_type& refHead, K const& val, Compare cmp ) const
799 node_type * pNode = base_class::get_at( refHead, val, cmp );
800 return pNode ? &pNode->m_Data : nullptr;
806 }} // namespace cds::container
808 #endif // #ifndef __CDS_CONTAINER_MICHAEL_KVLIST_RCU_H