3 #ifndef CDSLIB_CONTAINER_IMPL_LAZY_KVLIST_H
4 #define CDSLIB_CONTAINER_IMPL_LAZY_KVLIST_H
7 #include <cds/container/details/guarded_ptr_cast.h>
9 namespace cds { namespace container {
11 /// Lazy ordered list (key-value pair)
12 /** @ingroup cds_nonintrusive_list
13 \anchor cds_nonintrusive_LazyKVList_gc
15 This is key-value variation of non-intrusive LazyList.
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>.
23 - \p GC - garbage collector
24 - \p Key - key type of an item to be stored in the list. It should be copy-constructible
25 - \p Value - value type to be stored in the list
26 - \p Traits - type traits, default is \p lazy_list::traits
27 It is possible to declare option-based list with cds::container::lazy_list::make_traits metafunction istead of \p Traits template
28 argument. For example, the following traits-based declaration of \p gc::HP lazy list
30 #include <cds/container/lazy_kvlist_hp.h>
31 // Declare comparator for the item
33 int operator ()( int i1, int i2 )
40 struct my_traits: public cds::container::lazy_list::traits
42 typedef my_compare compare;
45 // Declare traits-based list
46 typedef cds::container::LazyKVList< cds::gc::HP, int, int, my_traits > traits_based_list;
48 is equal to the following option-based list
50 #include <cds/container/lazy_kvlist_hp.h>
52 // my_compare is the same
54 // Declare option-based list
55 typedef cds::container::LazyKVList< cds::gc::HP, int, int,
56 typename cds::container::lazy_list::make_traits<
57 cds::container::opt::compare< my_compare > // item comparator option
63 There are different specializations of this template for each garbage collecting schema used.
64 You should include appropriate .h-file depending on GC you are using:
65 - for \p gc::HP: <tt> <cds/container/lazy_kvlist_hp.h> </tt>
66 - for \p gc::DHP: <tt> <cds/container/lazy_kvlist_dhp.h> </tt>
67 - for \ref cds_urcu_desc "RCU": <tt> <cds/container/lazy_kvlist_rcu.h> </tt>
68 - for \p gc::nogc: <tt> <cds/container/lazy_kvlist_nogc.h> </tt>
74 #ifdef CDS_DOXYGEN_INVOKED
75 typename Traits = lazy_list::traits
81 #ifdef CDS_DOXYGEN_INVOKED
82 protected intrusive::LazyList< GC, implementation_defined, Traits >
84 protected details::make_lazy_kvlist< GC, Key, Value, Traits >::type
88 typedef details::make_lazy_kvlist< GC, Key, Value, Traits > maker;
89 typedef typename maker::type base_class;
93 typedef GC gc; ///< Garbage collector
94 #ifdef CDS_DOXYGEN_INVOKED
95 typedef Key key_type ; ///< Key type
96 typedef Value mapped_type ; ///< Type of value stored in the list
97 typedef std::pair<key_type const, mapped_type> value_type ; ///< key/value pair stored in the list
99 typedef typename maker::key_type key_type;
100 typedef typename maker::mapped_type mapped_type;
101 typedef typename maker::value_type value_type;
103 typedef typename base_class::back_off back_off; ///< Back-off strategy
104 typedef typename maker::allocator_type allocator_type; ///< Allocator type used for allocate/deallocate the nodes
105 typedef typename base_class::item_counter item_counter; ///< Item counter type
106 typedef typename maker::key_comparator key_comparator; ///< key comparing functor
107 typedef typename base_class::memory_model memory_model; ///< Memory ordering. See \p cds::opt::memory_model
111 typedef typename base_class::value_type node_type;
112 typedef typename maker::cxx_allocator cxx_allocator;
113 typedef typename maker::node_deallocator node_deallocator;
114 typedef typename maker::intrusive_traits::compare intrusive_key_comparator;
116 typedef typename base_class::node_type head_type;
121 typedef typename gc::template guarded_ptr< node_type, value_type, details::guarded_ptr_cast_map<node_type, value_type> > guarded_ptr;
125 template <typename K>
126 static node_type * alloc_node(const K& key)
128 return cxx_allocator().New( key );
131 template <typename K, typename V>
132 static node_type * alloc_node( const K& key, const V& val )
134 return cxx_allocator().New( key, val );
137 template <typename... Args>
138 static node_type * alloc_node( Args&&... args )
140 return cxx_allocator().MoveNew( std::forward<Args>(args)... );
143 static void free_node( node_type * pNode )
145 cxx_allocator().Delete( pNode );
148 struct node_disposer {
149 void operator()( node_type * pNode )
154 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
158 return base_class::m_Head;
161 head_type const& head() const
163 return base_class::m_Head;
168 return base_class::m_Tail;
171 head_type const& tail() const
173 return base_class::m_Tail;
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( const_cast<head_type *>(&pNode) )
188 iterator_type( head_type const * pNode )
189 : iterator_base( const_cast<head_type *>(pNode) )
192 friend class LazyKVList;
195 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
196 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
198 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
199 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
204 iterator_type( iterator_type const& src )
205 : iterator_base( src )
208 key_type const& key() const
210 typename iterator_base::value_ptr p = iterator_base::operator ->();
211 assert( p != nullptr );
212 return p->m_Data.first;
215 value_ref val() const
217 typename iterator_base::value_ptr p = iterator_base::operator ->();
218 assert( p != nullptr );
219 return p->m_Data.second;
222 pair_ptr operator ->() const
224 typename iterator_base::value_ptr p = iterator_base::operator ->();
225 return p ? &(p->m_Data) : nullptr;
228 pair_ref operator *() const
230 typename iterator_base::value_ref p = iterator_base::operator *();
235 iterator_type& operator ++()
237 iterator_base::operator ++();
242 bool operator ==(iterator_type<C> const& i ) const
244 return iterator_base::operator ==(i);
247 bool operator !=(iterator_type<C> const& i ) const
249 return iterator_base::operator !=(i);
257 The forward iterator for lazy list has some features:
258 - it has no post-increment operator
259 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
260 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
261 may be thrown if a limit of guard count per thread is exceeded.
262 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
263 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
264 deleting operations it is no guarantee that you iterate all item in the list.
266 Therefore, the use of iterators in concurrent environment is not good idea. Use the iterator on the concurrent container
267 for debug purpose only.
269 The iterator interface to access item data:
270 - <tt> operator -> </tt> - returns a pointer to \ref value_type for iterator
271 - <tt> operator *</tt> - returns a reference (a const reference for \p const_iterator) to \ref value_type for iterator
272 - <tt> const key_type& key() </tt> - returns a key reference for iterator
273 - <tt> mapped_type& val() </tt> - retuns a value reference for iterator (const reference for \p const_iterator)
275 For both functions the iterator should not be equal to <tt> end() </tt>
277 typedef iterator_type<false> iterator;
279 /// Const forward iterator
281 For iterator's features and requirements see \ref iterator
283 typedef iterator_type<true> const_iterator;
285 /// Returns a forward iterator addressing the first element in a list
287 For empty list \code begin() == end() \endcode
291 iterator it( head() );
292 ++it ; // skip dummy head
296 /// Returns an iterator that addresses the location succeeding the last element in a list
298 Do not use the value returned by <tt>end</tt> function to access any item.
299 Internally, <tt>end</tt> returning value equals to \p nullptr.
301 The returned value can be used only to control reaching the end of the list.
302 For empty list \code begin() == end() \endcode
306 return iterator( tail() );
309 /// Returns a forward const iterator addressing the first element in a list
311 const_iterator begin() const
313 const_iterator it( head() );
314 ++it; // skip dummy head
317 const_iterator cbegin() const
319 const_iterator it( head() );
320 ++it; // skip dummy head
325 /// Returns an const iterator that addresses the location succeeding the last element in a list
327 const_iterator end() const
329 return const_iterator( tail());
331 const_iterator cend() const
333 return const_iterator( tail());
338 /// Default constructor
342 /// Destructor clears the list
348 /// Inserts new node with key and default value
350 The function creates a node with \p key and default value, and then inserts the node created into the list.
353 - The \ref key_type should be constructible from value of type \p K.
354 In trivial case, \p K is equal to \ref key_type.
355 - The \ref mapped_type should be default-constructible.
357 Returns \p true if inserting successful, \p false otherwise.
359 template <typename K>
360 bool insert( const K& key )
362 return insert_at( head(), key );
365 /// Inserts new node with a key and a value
367 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
370 - The \ref key_type should be constructible from \p key of type \p K.
371 - The \ref mapped_type should be constructible from \p val of type \p V.
373 Returns \p true if inserting successful, \p false otherwise.
375 template <typename K, typename V>
376 bool insert( const K& key, const V& val )
378 // We cannot use insert with functor here
379 // because we cannot lock inserted node for updating
380 // Therefore, we use separate function
381 return insert_at( head(), key, val );
384 /// Inserts new node and initializes it by a functor
386 This function inserts new node with key \p key and if inserting is successful then it calls
387 \p func functor with signature
390 void operator()( value_type& item );
394 The argument \p item of user-defined functor \p func is the reference
395 to the list's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
396 The user-defined functor is called only if inserting is successful.
398 The \p key_type should be constructible from value of type \p K.
400 The function allows to split creating of new item into two part:
401 - create item from \p key;
402 - insert new item into the list;
403 - if inserting is successful, initialize the value of item by calling \p func functor
405 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
406 it is preferable that the initialization should be completed only if inserting is successful.
408 template <typename K, typename Func>
409 bool insert_with( const K& key, Func func )
411 return insert_with_at( head(), key, func );
414 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
416 Returns \p true if inserting successful, \p false otherwise.
418 template <typename... Args>
419 bool emplace( Args&&... args )
421 return emplace_at( head(), std::forward<Args>(args)... );
424 /// Updates data by \p key
426 The operation performs inserting or replacing the element with lock-free manner.
428 If the \p key not found in the list, then the new item created from \p key
429 will be inserted iff \p bAllowInsert is \p true.
430 (note that in this case the \ref key_type should be constructible from type \p K).
431 Otherwise, if \p key is found, the functor \p func is called with item found.
433 The functor \p Func signature is:
436 void operator()( bool bNew, value_type& item );
440 - \p bNew - \p true if the item has been inserted, \p false otherwise
441 - \p item - the item found or inserted
443 The functor may change any fields of the \p item.second of \p mapped_type;
444 during \p func call \p item is locked so it is safe to modify the item in
445 multi-threaded environment.
447 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
448 \p second is true if new item has been added or \p false if the item with \p key
451 template <typename K, typename Func>
452 std::pair<bool, bool> update( const K& key, Func f, bool bAllowInsert = true )
454 return update_at( head(), key, f, bAllowInsert );
458 template <typename K, typename Func>
459 std::pair<bool, bool> ensure( const K& key, Func f )
461 return update( key, f, true );
465 /// Deletes \p key from the list
466 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_val
468 Returns \p true if \p key is found and has been deleted, \p false otherwise
470 template <typename K>
471 bool erase( K const& key )
473 return erase_at( head(), key, intrusive_key_comparator() );
476 /// Deletes the item from the list using \p pred predicate for searching
478 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_val "erase(K const&)"
479 but \p pred is used for key comparing.
480 \p Less functor has the interface like \p std::less.
481 \p pred must imply the same element order as the comparator used for building the list.
483 template <typename K, typename Less>
484 bool erase_with( K const& key, Less pred )
487 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
490 /// Deletes \p key from the list
491 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_func
492 The function searches an item with key \p key, calls \p f functor with item found
493 and deletes it. If \p key is not found, the functor is not called.
495 The functor \p Func interface:
498 void operator()(value_type& val) { ... }
502 Returns \p true if key is found and deleted, \p false otherwise
504 template <typename K, typename Func>
505 bool erase( K const& key, Func f )
507 return erase_at( head(), key, intrusive_key_comparator(), f );
510 /// Deletes the item from the list using \p pred predicate for searching
512 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_func "erase(K const&, Func)"
513 but \p pred is used for key comparing.
514 \p Less functor has the interface like \p std::less.
515 \p pred must imply the same element order as the comparator used for building the list.
517 template <typename K, typename Less, typename Func>
518 bool erase_with( K const& key, Less pred, Func f )
521 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
524 /// Extracts the item from the list with specified \p key
525 /** \anchor cds_nonintrusive_LazyKVList_hp_extract
526 The function searches an item with key equal to \p key,
527 unlinks it from the list, and returns it as \p guarded_ptr.
528 If \p key is not found the function returns an empty guarded pointer.
530 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
532 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
536 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
540 ord_list::guarded_ptr gp( theList.extract( 5 ));
545 // Destructor of gp releases internal HP guard and frees the item
549 template <typename K>
550 guarded_ptr extract( K const& key )
553 extract_at( head(), gp.guard(), key, intrusive_key_comparator() );
557 /// Extracts the item from the list with comparing functor \p pred
559 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_extract "extract(K const&)"
560 but \p pred predicate is used for key comparing.
562 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
564 \p pred must imply the same element order as the comparator used for building the list.
566 template <typename K, typename Less>
567 guarded_ptr extract_with( K const& key, Less pred )
571 extract_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
575 /// Checks whether the list contains \p key
577 The function searches the item with key equal to \p key
578 and returns \p true if it is found, and \p false otherwise.
580 template <typename Q>
581 bool contains( Q const& key )
583 return find_at( head(), key, intrusive_key_comparator() );
587 template <typename Q>
588 bool find( Q const& key )
590 return contains( key );
594 /// Checks whether the map contains \p key using \p pred predicate for searching
596 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
597 \p Less functor has the interface like \p std::less.
598 \p Less must imply the same element order as the comparator used for building the list.
600 template <typename Q, typename Less>
601 bool contains( Q const& key, Less pred )
604 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
608 template <typename Q, typename Less>
609 bool find_with( Q const& key, Less pred )
611 return contains( key, pred );
615 /// Finds the key \p key and performs an action with it
616 /** \anchor cds_nonintrusive_LazyKVList_hp_find_func
617 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
618 The interface of \p Func functor is:
621 void operator()( value_type& item );
624 where \p item is the item found.
626 The functor may change <tt>item.second</tt> that is reference to value of node.
627 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
628 The function does not serialize simultaneous access to the list \p item. If such access is
629 possible you must provide your own synchronization schema to exclude unsafe item modifications.
631 The function returns \p true if \p key is found, \p false otherwise.
633 template <typename Q, typename Func>
634 bool find( Q const& key, Func f )
636 return find_at( head(), key, intrusive_key_comparator(), f );
639 /// Finds the key \p val using \p pred predicate for searching
641 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_find_func "find(Q&, Func)"
642 but \p pred is used for key comparing.
643 \p Less functor has the interface like \p std::less.
644 \p pred must imply the same element order as the comparator used for building the list.
646 template <typename Q, typename Less, typename Func>
647 bool find_with( Q const& key, Less pred, Func f )
650 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
653 /// Finds \p key and return the item found
654 /** \anchor cds_nonintrusive_LazyKVList_hp_get
655 The function searches the item with key equal to \p key
656 and returns the item found as a guarded pointer.
657 If \p key is not found the functions returns an empty \p guarded_ptr.
659 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
663 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
667 ord_list::guarded_ptr gp( theList.get( 5 ));
672 // Destructor of guarded_ptr releases internal HP guard and frees the item
676 Note the compare functor specified for class \p Traits template parameter
677 should accept a parameter of type \p K that can be not the same as \p key_type.
679 template <typename K>
680 guarded_ptr get( K const& key )
683 get_at( head(), gp.guard(), key, intrusive_key_comparator() );
687 /// Finds the key \p val and return the item found
689 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_get "get(K const&)"
690 but \p pred is used for comparing the keys.
692 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
694 \p pred must imply the same element order as the comparator used for building the list.
696 template <typename K, typename Less>
697 guarded_ptr get_with( K const& key, Less pred )
701 get_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
705 /// Checks if the list is empty
708 return base_class::empty();
711 /// Returns list's item count
713 The value returned depends on opt::item_counter option. For atomicity::empty_item_counter,
714 this function always returns 0.
716 @note Even if you use real item counter and it returns 0, this fact is not mean that the list
717 is empty. To check list emptyness use \ref empty() method.
721 return base_class::size();
732 bool insert_node_at( head_type& refHead, node_type * pNode )
734 assert( pNode != nullptr );
735 scoped_node_ptr p( pNode );
737 if ( base_class::insert_at( &refHead, *p )) {
745 template <typename K>
746 bool insert_at( head_type& refHead, const K& key )
748 return insert_node_at( refHead, alloc_node( key ));
751 template <typename K, typename V>
752 bool insert_at( head_type& refHead, const K& key, const V& val )
754 return insert_node_at( refHead, alloc_node( key, val ));
757 template <typename K, typename Func>
758 bool insert_with_at( head_type& refHead, const K& key, Func f )
760 scoped_node_ptr pNode( alloc_node( key ));
762 if ( base_class::insert_at( &refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); } )) {
769 template <typename... Args>
770 bool emplace_at( head_type& refHead, Args&&... args )
772 return insert_node_at( refHead, alloc_node( std::forward<Args>(args)... ));
775 template <typename K, typename Compare>
776 bool erase_at( head_type& refHead, K const& key, Compare cmp )
778 return base_class::erase_at( &refHead, key, cmp );
781 template <typename K, typename Compare, typename Func>
782 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
784 return base_class::erase_at( &refHead, key, cmp, [&f](node_type const & node){f( const_cast<value_type&>(node.m_Data)); });
787 template <typename K, typename Compare>
788 bool extract_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
790 return base_class::extract_at( &refHead, guard, key, cmp );
793 template <typename K, typename Func>
794 std::pair<bool, bool> update_at( head_type& refHead, const K& key, Func f, bool bAllowInsert )
796 scoped_node_ptr pNode( alloc_node( key ));
798 std::pair<bool, bool> ret = base_class::update_at( &refHead, *pNode,
799 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); },
801 if ( ret.first && ret.second )
807 template <typename K, typename Compare>
808 bool find_at( head_type& refHead, K const& key, Compare cmp )
810 return base_class::find_at( &refHead, key, cmp );
813 template <typename K, typename Compare, typename Func>
814 bool find_at( head_type& refHead, K& key, Compare cmp, Func f )
816 return base_class::find_at( &refHead, key, cmp, [&f]( node_type& node, K& ){ f( node.m_Data ); });
819 template <typename K, typename Compare>
820 bool get_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
822 return base_class::get_at( &refHead, guard, key, cmp );
828 }} // namespace cds::container
830 #endif // #ifndef CDSLIB_CONTAINER_IMPL_LAZY_KVLIST_H