3 #ifndef __CDS_CONTAINER_IMPL_MICHAEL_KVLIST_H
4 #define __CDS_CONTAINER_IMPL_MICHAEL_KVLIST_H
7 #include <cds/container/details/guarded_ptr_cast.h>
9 namespace cds { namespace container {
11 /// Michael's ordered list fo key-value pair
12 /** @ingroup cds_nonintrusive_list
13 \anchor cds_nonintrusive_MichaelKVList_gc
15 This is key-value variation of non-intrusive MichaelList.
16 Like standard container, this implementation split a value stored into two part -
17 constant key and alterable value.
19 Usually, ordered single-linked list is used as a building block for the hash table implementation.
20 The complexity of searching is <tt>O(N)</tt> where \p N is the item count in the list, not in the
24 - \p GC - garbage collector used
25 - \p Key - key type of an item stored in the list. It should be copy-constructible
26 - \p Value - value type stored in a list
27 - \p Traits - type traits, default is \p michael_list::traits
29 It is possible to declare option-based list with \p cds::container::michael_list::make_traits metafunction istead of \p Traits template
30 argument. For example, the following traits-based declaration of \p gc::HP Michael's list
32 #include <cds/container/michael_kvlist_hp.h>
33 // Declare comparator for the item
35 int operator ()( int i1, int i2 )
42 struct my_traits: public cds::container::michael_list::traits
44 typedef my_compare compare;
47 // Declare traits-based list
48 typedef cds::container::MichaelKVList< cds::gc::HP, int, int, my_traits > traits_based_list;
50 is equivalent for the following option-based list
52 #include <cds/container/michael_kvlist_hp.h>
54 // my_compare is the same
56 // Declare option-based list
57 typedef cds::container::MichaelKVList< cds::gc::HP, int, int,
58 typename cds::container::michael_list::make_traits<
59 cds::container::opt::compare< my_compare > // item comparator option
65 There are different specializations of this template for each garbage collecting schema used.
66 You should include appropriate .h-file depending on GC you are using:
67 - for gc::HP: \code #include <cds/container/michael_kvlist_hp.h> \endcode
68 - for gc::DHP: \code #include <cds/container/michael_kvlist_dhp.h> \endcode
69 - for \ref cds_urcu_desc "RCU": \code #include <cds/container/michael_kvlist_rcu.h> \endcode
70 - for gc::nogc: \code #include <cds/container/michael_kvlist_nogc.h> \endcode
76 #ifdef CDS_DOXYGEN_INVOKED
77 typename Traits = michael_list::traits
83 #ifdef CDS_DOXYGEN_INVOKED
84 protected intrusive::MichaelList< GC, implementation_defined, Traits >
86 protected details::make_michael_kvlist< GC, Key, Value, Traits >::type
90 typedef details::make_michael_kvlist< GC, 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;
105 typedef typename base_class::gc gc; ///< Garbage collector used
106 typedef typename base_class::back_off back_off; ///< Back-off strategy used
107 typedef typename maker::allocator_type allocator_type; ///< Allocator type used for allocate/deallocate the nodes
108 typedef typename base_class::item_counter item_counter; ///< Item counting policy used
109 typedef typename maker::key_comparator key_comparator; ///< key comparison functor
110 typedef typename base_class::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
114 typedef typename base_class::value_type node_type;
115 typedef typename maker::cxx_allocator cxx_allocator;
116 typedef typename maker::node_deallocator node_deallocator;
117 typedef typename maker::intrusive_traits::compare intrusive_key_comparator;
119 typedef typename base_class::atomic_node_ptr head_type;
124 typedef cds::gc::guarded_ptr< gc, node_type, value_type, details::guarded_ptr_cast_map<node_type, value_type> > guarded_ptr;
128 template <typename K>
129 static node_type * alloc_node(const K& key)
131 return cxx_allocator().New( key );
134 template <typename K, typename V>
135 static node_type * alloc_node( const K& key, const V& val )
137 return cxx_allocator().New( key, val );
140 template <typename K, typename... Args>
141 static node_type * alloc_node( K&& key, Args&&... args )
143 return cxx_allocator().MoveNew( std::forward<K>(key), std::forward<Args>(args)...);
146 static void free_node( node_type * pNode )
148 cxx_allocator().Delete( pNode );
151 struct node_disposer {
152 void operator()( node_type * pNode )
157 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
161 return base_class::m_pHead;
164 head_type const& head() const
166 return base_class::m_pHead;
172 template <bool IsConst>
173 class iterator_type: protected base_class::template iterator_type<IsConst>
175 typedef typename base_class::template iterator_type<IsConst> iterator_base;
177 iterator_type( head_type const& pNode )
178 : iterator_base( pNode )
181 friend class MichaelKVList;
184 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
185 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
187 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
188 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
193 iterator_type( iterator_type const& src )
194 : iterator_base( src )
197 key_type const& key() const
199 typename iterator_base::value_ptr p = iterator_base::operator ->();
200 assert( p != nullptr );
201 return p->m_Data.first;
204 pair_ptr operator ->() const
206 typename iterator_base::value_ptr p = iterator_base::operator ->();
207 return p ? &(p->m_Data) : nullptr;
210 pair_ref operator *() const
212 typename iterator_base::value_ref p = iterator_base::operator *();
216 value_ref val() const
218 typename iterator_base::value_ptr p = iterator_base::operator ->();
219 assert( p != nullptr );
220 return p->m_Data.second;
224 iterator_type& operator ++()
226 iterator_base::operator ++();
231 bool operator ==(iterator_type<C> const& i ) const
233 return iterator_base::operator ==(i);
236 bool operator !=(iterator_type<C> const& i ) const
238 return iterator_base::operator !=(i);
246 The forward iterator for Michael's list has some features:
247 - it has no post-increment operator
248 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
249 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
250 may be thrown if a limit of guard count per thread is exceeded.
251 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
252 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
253 deleting operations it is no guarantee that you iterate all item in the list.
255 Therefore, the use of iterators in concurrent environment is not good idea. Use the iterator on the concurrent container
256 for debug purpose only.
258 The iterator interface to access item data:
259 - <tt> operator -> </tt> - returns a pointer to \ref value_type for iterator
260 - <tt> operator *</tt> - returns a reference (a const reference for \p const_iterator) to \ref value_type for iterator
261 - <tt> const key_type& key() </tt> - returns a key reference for iterator
262 - <tt> mapped_type& val() </tt> - retuns a value reference for iterator (const reference for \p const_iterator)
264 For both functions the iterator should not be equal to <tt> end() </tt>
266 typedef iterator_type<false> iterator;
268 /// Const forward iterator
270 For iterator's features and requirements see \ref iterator
272 typedef iterator_type<true> const_iterator;
274 /// Returns a forward iterator addressing the first element in a list
276 For empty list \code begin() == end() \endcode
280 return iterator( head() );
283 /// Returns an iterator that addresses the location succeeding the last element in a list
285 Do not use the value returned by <tt>end</tt> function to access any item.
286 Internally, <tt>end</tt> returning value equals to \p nullptr.
288 The returned value can be used only to control reaching the end of the list.
289 For empty list \code begin() == end() \endcode
296 /// Returns a forward const iterator addressing the first element in a list
298 const_iterator begin() const
300 return const_iterator( head() );
302 const_iterator cbegin() const
304 return const_iterator( head() );
308 /// Returns an const iterator that addresses the location succeeding the last element in a list
310 const_iterator end() const
312 return const_iterator();
314 const_iterator cend() const
316 return const_iterator();
321 /// Default constructor
323 Initializes empty list
337 /// Inserts new node with key and default value
339 The function creates a node with \p key and default value, and then inserts the node created into the list.
342 - The \p key_type should be constructible from value of type \p K.
343 In trivial case, \p K is equal to \p key_type.
344 - The \p mapped_type should be default-constructible.
346 Returns \p true if inserting successful, \p false otherwise.
348 template <typename K>
349 bool insert( const K& key )
351 return insert_at( head(), key );
354 /// Inserts new node with a key and a value
356 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
359 - The \p key_type should be constructible from \p key of type \p K.
360 - The \p mapped_type should be constructible from \p val of type \p V.
362 Returns \p true if inserting successful, \p false otherwise.
364 template <typename K, typename V>
365 bool insert( const K& key, const V& val )
367 // We cannot use insert with functor here
368 // because we cannot lock inserted node for updating
369 // Therefore, we use separate function
370 return insert_at( head(), key, val );
373 /// Inserts new node and initialize it by a functor
375 This function inserts new node with key \p key and if inserting is successful then it calls
376 \p func functor with signature
379 void operator()( value_type& item );
383 The argument \p item of user-defined functor \p func is the reference
384 to the item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
385 User-defined functor \p func should guarantee that during changing item's value no any other changes
386 could be made on this list's item by concurrent threads.
387 The user-defined functor is called only if inserting is successful.
389 The \p key_type should be constructible from value of type \p K.
391 The function allows to split creating of new item into two part:
392 - create a new item from \p key;
393 - insert the new item into the list;
394 - if inserting is successful, initialize the value of item by calling \p func functor
396 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
397 it is preferable that the initialization should be completed only if inserting is successful.
399 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
401 template <typename K, typename Func>
402 bool insert_key( const K& key, Func func )
404 return insert_key_at( head(), key, func );
407 /// Ensures that the \p key exists in the list
409 The operation performs inserting or changing data with lock-free manner.
411 If the \p key not found in the list, then the new item created from \p key
412 is inserted into the list (note that in this case the \p key_type should be
413 copy-constructible from type \p K).
414 Otherwise, the functor \p func is called with item found.
415 The functor \p Func may be a function with signature:
417 void func( bool bNew, value_type& item );
422 void operator()( bool bNew, value_type& item );
427 - \p bNew - \p true if the item has been inserted, \p false otherwise
428 - \p item - item of the list
430 The functor may change any fields of the \p item.second of \p mapped_type;
431 however, \p func must guarantee that during changing no any other modifications
432 could be made on this item by concurrent threads.
434 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
435 \p second is true if new item has been added or \p false if the item with \p key
436 already is in the list.
438 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
440 template <typename K, typename Func>
441 std::pair<bool, bool> ensure( const K& key, Func f )
443 return ensure_at( head(), key, f );
446 /// Inserts a new node using move semantics
448 \p key_type field of new item is constructed from \p key argument,
449 \p mapped_type field is done from \p args.
451 Returns \p true if inserting successful, \p false otherwise.
453 template <typename K, typename... Args>
454 bool emplace( K&& key, Args&&... args )
456 return emplace_at( head(), std::forward<K>(key), std::forward<Args>(args)... );
459 /// Deletes \p key from the list
460 /** \anchor cds_nonintrusive_MichaelKVList_hp_erase_val
462 Returns \p true if \p key is found and has been deleted, \p false otherwise
464 template <typename K>
465 bool erase( K const& key )
467 return erase_at( head(), key, intrusive_key_comparator() );
470 /// Deletes the item from the list using \p pred predicate for searching
472 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_erase_val "erase(K const&)"
473 but \p pred is used for key comparing.
474 \p Less functor has the interface like \p std::less.
475 \p pred must imply the same element order as the comparator used for building the list.
477 template <typename K, typename Less>
478 bool erase_with( K const& key, Less pred )
480 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
483 /// Deletes \p key from the list
484 /** \anchor cds_nonintrusive_MichaelKVList_hp_erase_func
485 The function searches an item with key \p key, calls \p f functor
486 and deletes the item. If \p key is not found, the functor is not called.
488 The functor \p Func interface:
491 void operator()(value_type& val) { ... }
495 Return \p true if key is found and deleted, \p false otherwise
499 template <typename K, typename Func>
500 bool erase( K const& key, Func f )
502 return erase_at( head(), key, intrusive_key_comparator(), f );
505 /// Deletes the item from the list using \p pred predicate for searching
507 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_erase_func "erase(K const&, Func)"
508 but \p pred is used for key comparing.
509 \p Less functor has the interface like \p std::less.
510 \p pred must imply the same element order as the comparator used for building the list.
512 template <typename K, typename Less, typename Func>
513 bool erase_with( K const& key, Less pred, Func f )
515 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
518 /// Extracts the item from the list with specified \p key
519 /** \anchor cds_nonintrusive_MichaelKVList_hp_extract
520 The function searches an item with key equal to \p key,
521 unlinks it from the list, and returns it in \p dest parameter.
522 If the item with key equal to \p key is not found the function returns \p false.
524 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
526 The \ref disposer specified in \p Traits class template parameter is called automatically
527 by garbage collector \p GC specified in class' template parameters when returned \ref guarded_ptr object
528 will be destroyed or released.
529 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
533 typedef cds::container::MichaelKVList< cds::gc::HP, int, foo, my_traits > ord_list;
537 ord_list::guarded_ptr gp;
538 theList.extract( gp, 5 );
542 // Destructor of gp releases internal HP guard
546 template <typename K>
547 bool extract( guarded_ptr& dest, K const& key )
549 return extract_at( head(), dest.guard(), key, intrusive_key_comparator() );
552 /// Extracts the item from the list with comparing functor \p pred
554 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_extract "extract(guarded_ptr&, K const&)"
555 but \p pred predicate is used for key comparing.
557 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
559 \p pred must imply the same element order as the comparator used for building the list.
561 template <typename K, typename Less>
562 bool extract_with( guarded_ptr& dest, K const& key, Less pred )
564 return extract_at( head(), dest.guard(), key, typename maker::template less_wrapper<Less>::type() );
567 /// Finds the key \p key
568 /** \anchor cds_nonintrusive_MichaelKVList_hp_find_val
569 The function searches the item with key equal to \p key
570 and returns \p true if it is found, and \p false otherwise
572 template <typename Q>
573 bool find( Q const& key )
575 return find_at( head(), key, intrusive_key_comparator() );
578 /// Finds the key \p val using \p pred predicate for searching
580 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_find_val "find(Q const&)"
581 but \p pred is used for key comparing.
582 \p Less functor has the interface like \p std::less.
583 \p pred must imply the same element order as the comparator used for building the list.
585 template <typename Q, typename Less>
586 bool find_with( Q const& key, Less pred )
588 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
591 /// Finds the key \p key and performs an action with it
592 /** \anchor cds_nonintrusive_MichaelKVList_hp_find_func
593 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
594 The interface of \p Func functor is:
597 void operator()( value_type& item );
600 where \p item is the item found.
602 The functor may change <tt>item.second</tt> that is reference to value of node.
603 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
604 The function does not serialize simultaneous access to the list \p item. If such access is
605 possible you must provide your own synchronization schema to exclude unsafe item modifications.
607 The function returns \p true if \p key is found, \p false otherwise.
609 template <typename Q, typename Func>
610 bool find( Q const& key, Func f )
612 return find_at( head(), key, intrusive_key_comparator(), f );
615 /// Finds the key \p val using \p pred predicate for searching
617 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_find_func "find(Q&, Func)"
618 but \p pred is used for key comparing.
619 \p Less functor has the interface like \p std::less.
620 \p pred must imply the same element order as the comparator used for building the list.
622 template <typename Q, typename Less, typename Func>
623 bool find_with( Q const& key, Less pred, Func f )
625 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
628 /// Finds the \p key and return the item found
629 /** \anchor cds_nonintrusive_MichaelKVList_hp_get
630 The function searches the item with key equal to \p key
631 and assigns the item found to guarded pointer \p ptr.
632 The function returns \p true if \p key is found, and \p false otherwise.
633 If \p key is not found the \p ptr parameter is not changed.
635 The \ref disposer specified in \p Traits class template parameter is called
636 by garbage collector \p GC automatically when returned \ref guarded_ptr object
637 will be destroyed or released.
638 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
642 typedef cds::container::MichaelKVList< cds::gc::HP, int, foo, my_traits > ord_list;
646 ord_list::guarded_ptr gp;
647 if ( theList.get( gp, 5 )) {
651 // Destructor of guarded_ptr releases internal HP guard
655 Note the compare functor specified for class \p Traits template parameter
656 should accept a parameter of type \p K that can be not the same as \p key_type.
658 template <typename K>
659 bool get( guarded_ptr& ptr, K const& key )
661 return get_at( head(), ptr.guard(), key, intrusive_key_comparator() );
664 /// Finds the \p key and return the item found
666 The function is an analog of \ref cds_nonintrusive_MichaelKVList_hp_get "get( guarded_ptr& ptr, K const&)"
667 but \p pred is used for comparing the keys.
669 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
671 \p pred must imply the same element order as the comparator used for building the list.
673 template <typename K, typename Less>
674 bool get_with( guarded_ptr& ptr, K const& key, Less pred )
676 return get_at( head(), ptr.guard(), key, typename maker::template less_wrapper<Less>::type() );
679 /// Checks if the list is empty
682 return base_class::empty();
685 /// Returns list's item count
687 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
688 this function always returns 0.
690 @note Even if you use real item counter and it returns 0, this fact is not mean that the list
691 is empty. To check list emptyness use \p empty() method.
695 return base_class::size();
706 bool insert_node_at( head_type& refHead, node_type * pNode )
708 assert( pNode != nullptr );
709 scoped_node_ptr p( pNode );
710 if ( base_class::insert_at( refHead, *pNode )) {
717 template <typename K>
718 bool insert_at( head_type& refHead, const K& key )
720 return insert_node_at( refHead, alloc_node( key ));
723 template <typename K, typename V>
724 bool insert_at( head_type& refHead, const K& key, const V& val )
726 return insert_node_at( refHead, alloc_node( key, val ));
729 template <typename K, typename Func>
730 bool insert_key_at( head_type& refHead, const K& key, Func f )
732 scoped_node_ptr pNode( alloc_node( key ));
734 if ( base_class::insert_at( refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); })) {
741 template <typename K, typename... Args>
742 bool emplace_at( head_type& refHead, K&& key, Args&&... args )
744 return insert_node_at( refHead, alloc_node( std::forward<K>(key), std::forward<Args>(args)... ));
747 template <typename K, typename Func>
748 std::pair<bool, bool> ensure_at( head_type& refHead, const K& key, Func f )
750 scoped_node_ptr pNode( alloc_node( key ));
752 std::pair<bool, bool> ret = base_class::ensure_at( refHead, *pNode,
753 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); });
754 if ( ret.first && ret.second )
760 template <typename K, typename Compare>
761 bool erase_at( head_type& refHead, K const& key, Compare cmp )
763 return base_class::erase_at( refHead, key, cmp );
766 template <typename K, typename Compare, typename Func>
767 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
769 return base_class::erase_at( refHead, key, cmp, [&f]( node_type const & node ){ f( const_cast<value_type&>(node.m_Data)); });
771 template <typename K, typename Compare>
772 bool extract_at( head_type& refHead, typename gc::Guard& dest, K const& key, Compare cmp )
774 return base_class::extract_at( refHead, dest, key, cmp );
777 template <typename K, typename Compare>
778 bool find_at( head_type& refHead, K const& key, Compare cmp )
780 return base_class::find_at( refHead, key, cmp );
783 template <typename K, typename Compare, typename Func>
784 bool find_at( head_type& refHead, K& key, Compare cmp, Func f )
786 return base_class::find_at( refHead, key, cmp, [&f](node_type& node, K const&){ f( node.m_Data ); });
789 template <typename K, typename Compare>
790 bool get_at( head_type& refHead, typename gc::Guard& guard, K const& key, Compare cmp )
792 return base_class::get_at( refHead, guard, key, cmp );
798 }} // namespace cds::container
800 #endif // #ifndef __CDS_CONTAINER_IMPL_MICHAEL_KVLIST_H