3 #ifndef __CDS_CONTAINER_IMPL_LAZY_KVLIST_H
4 #define __CDS_CONTAINER_IMPL_LAZY_KVLIST_H
7 #include <functional> // ref
8 #include <cds/container/details/guarded_ptr_cast.h>
10 namespace cds { namespace container {
12 /// Lazy ordered list (key-value pair)
13 /** @ingroup cds_nonintrusive_list
14 \anchor cds_nonintrusive_LazyKVList_gc
16 This is key-value variation of non-intrusive LazyList.
17 Like standard container, this implementation split a value stored into two part -
18 constant key and alterable value.
20 Usually, ordered single-linked list is used as a building block for the hash table implementation.
21 The complexity of searching is <tt>O(N)</tt>.
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 the list
27 - \p Traits - type traits, default is lazy_list::type_traits
29 It is possible to declare option-based list with cds::container::lazy_list::make_traits metafunction istead of \p Traits template
30 argument. For example, the following traits-based declaration of gc::HP lazy list
32 #include <cds/container/lazy_kvlist_hp.h>
33 // Declare comparator for the item
35 int operator ()( int i1, int i2 )
41 // Declare type_traits
42 struct my_traits: public cds::container::lazy_list::type_traits
44 typedef my_compare compare;
47 // Declare traits-based list
48 typedef cds::container::LazyKVList< cds::gc::HP, int, int, my_traits > traits_based_list;
51 is equivalent for the following option-based list
53 #include <cds/container/lazy_kvlist_hp.h>
55 // my_compare is the same
57 // Declare option-based list
58 typedef cds::container::LazyKVList< cds::gc::HP, int, int,
59 typename cds::container::lazy_list::make_traits<
60 cds::container::opt::compare< my_compare > // item comparator option
65 Template argument list \p Options of cds::container::lazy_list::make_traits metafunction are:
66 - opt::compare - key comparison functor. No default functor is provided.
67 If the option is not specified, the opt::less is used.
68 - opt::less - specifies binary predicate used for key comparison. Default is \p std::less<T>.
69 - opt::back_off - back-off strategy used. If the option is not specified, the cds::backoff::empty is used.
70 - opt::item_counter - the type of item counting feature. Default is \ref atomicity::empty_item_counter that is no item counting.
71 - opt::allocator - the allocator used for creating and freeing list's item. Default is \ref CDS_DEFAULT_ALLOCATOR macro.
72 - opt::memory_model - C++ memory ordering model. Can be opt::v::relaxed_ordering (relaxed memory model, the default)
73 or opt::v::sequential_consistent (sequentially consisnent memory model).
76 There are different specializations of this template for each garbage collecting schema used.
77 You should include appropriate .h-file depending on GC you are using:
78 - for gc::HP: \code #include <cds/container/lazy_kvlist_hp.h> \endcode
79 - for gc::DHP: \code #include <cds/container/lazy_kvlist_dhp.h> \endcode
80 - for \ref cds_urcu_desc "RCU": \code #include <cds/container/lazy_kvlist_rcu.h> \endcode
81 - for gc::nogc: \code #include <cds/container/lazy_kvlist_nogc.h> \endcode
87 #ifdef CDS_DOXYGEN_INVOKED
88 typename Traits = lazy_list::type_traits
94 #ifdef CDS_DOXYGEN_INVOKED
95 protected intrusive::LazyList< GC, implementation_defined, Traits >
97 protected details::make_lazy_kvlist< GC, Key, Value, Traits >::type
101 typedef details::make_lazy_kvlist< GC, Key, Value, Traits > options;
102 typedef typename options::type base_class;
106 #ifdef CDS_DOXYGEN_INVOKED
107 typedef Key key_type ; ///< Key type
108 typedef Value mapped_type ; ///< Type of value stored in the list
109 typedef std::pair<key_type const, mapped_type> value_type ; ///< key/value pair stored in the list
111 typedef typename options::key_type key_type;
112 typedef typename options::value_type mapped_type;
113 typedef typename options::pair_type value_type;
116 typedef typename base_class::gc gc ; ///< Garbage collector used
117 typedef typename base_class::back_off back_off ; ///< Back-off strategy used
118 typedef typename options::allocator_type allocator_type ; ///< Allocator type used for allocate/deallocate the nodes
119 typedef typename base_class::item_counter item_counter ; ///< Item counting policy used
120 typedef typename options::key_comparator key_comparator ; ///< key comparison functor
121 typedef typename base_class::memory_model memory_model ; ///< Memory ordering. See cds::opt::memory_model option
125 typedef typename base_class::value_type node_type;
126 typedef typename options::cxx_allocator cxx_allocator;
127 typedef typename options::node_deallocator node_deallocator;
128 typedef typename options::type_traits::compare intrusive_key_comparator;
130 typedef typename base_class::node_type head_type;
135 typedef cds::gc::guarded_ptr< gc, node_type, value_type, details::guarded_ptr_cast_map<node_type, value_type> > guarded_ptr;
139 template <typename K>
140 static node_type * alloc_node(const K& key)
142 return cxx_allocator().New( key );
145 template <typename K, typename V>
146 static node_type * alloc_node( const K& key, const V& val )
148 return cxx_allocator().New( key, val );
151 template <typename... Args>
152 static node_type * alloc_node( Args&&... args )
154 return cxx_allocator().MoveNew( std::forward<Args>(args)... );
157 static void free_node( node_type * pNode )
159 cxx_allocator().Delete( pNode );
162 struct node_disposer {
163 void operator()( node_type * pNode )
168 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
172 return *base_class::head();
175 head_type const& head() const
177 return *base_class::head();
182 return *base_class::tail();
185 head_type const& tail() const
187 return *base_class::tail();
194 template <bool IsConst>
195 class iterator_type: protected base_class::template iterator_type<IsConst>
197 typedef typename base_class::template iterator_type<IsConst> iterator_base;
199 iterator_type( head_type const& pNode )
200 : iterator_base( const_cast<head_type *>(&pNode) )
202 iterator_type( head_type const * pNode )
203 : iterator_base( const_cast<head_type *>(pNode) )
206 friend class LazyKVList;
209 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
210 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
212 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
213 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
218 iterator_type( iterator_type const& src )
219 : iterator_base( src )
222 key_type const& key() const
224 typename iterator_base::value_ptr p = iterator_base::operator ->();
225 assert( p != nullptr );
226 return p->m_Data.first;
229 value_ref val() const
231 typename iterator_base::value_ptr p = iterator_base::operator ->();
232 assert( p != nullptr );
233 return p->m_Data.second;
236 pair_ptr operator ->() const
238 typename iterator_base::value_ptr p = iterator_base::operator ->();
239 return p ? &(p->m_Data) : nullptr;
242 pair_ref operator *() const
244 typename iterator_base::value_ref p = iterator_base::operator *();
249 iterator_type& operator ++()
251 iterator_base::operator ++();
256 bool operator ==(iterator_type<C> const& i ) const
258 return iterator_base::operator ==(i);
261 bool operator !=(iterator_type<C> const& i ) const
263 return iterator_base::operator !=(i);
271 The forward iterator for lazy list has some features:
272 - it has no post-increment operator
273 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
274 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
275 may be thrown if a limit of guard count per thread is exceeded.
276 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
277 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
278 deleting operations it is no guarantee that you iterate all item in the list.
280 Therefore, the use of iterators in concurrent environment is not good idea. Use the iterator on the concurrent container
281 for debug purpose only.
283 The iterator interface to access item data:
284 - <tt> operator -> </tt> - returns a pointer to \ref value_type for iterator
285 - <tt> operator *</tt> - returns a reference (a const reference for \p const_iterator) to \ref value_type for iterator
286 - <tt> const key_type& key() </tt> - returns a key reference for iterator
287 - <tt> mapped_type& val() </tt> - retuns a value reference for iterator (const reference for \p const_iterator)
289 For both functions the iterator should not be equal to <tt> end() </tt>
291 typedef iterator_type<false> iterator;
293 /// Const forward iterator
295 For iterator's features and requirements see \ref iterator
297 typedef iterator_type<true> const_iterator;
299 /// Returns a forward iterator addressing the first element in a list
301 For empty list \code begin() == end() \endcode
305 iterator it( head() );
306 ++it ; // skip dummy head
310 /// Returns an iterator that addresses the location succeeding the last element in a list
312 Do not use the value returned by <tt>end</tt> function to access any item.
313 Internally, <tt>end</tt> returning value equals to \p nullptr.
315 The returned value can be used only to control reaching the end of the list.
316 For empty list \code begin() == end() \endcode
320 return iterator( tail() );
323 /// Returns a forward const iterator addressing the first element in a list
325 const_iterator begin() const
327 const_iterator it( head() );
328 ++it; // skip dummy head
331 const_iterator cbegin()
333 const_iterator it( head() );
334 ++it; // skip dummy head
339 /// Returns an const iterator that addresses the location succeeding the last element in a list
341 const_iterator end() const
343 return const_iterator( tail());
345 const_iterator cend()
347 return const_iterator( tail());
352 /// Default constructor
354 Initializes empty list
368 /// Inserts new node with key and default value
370 The function creates a node with \p key and default value, and then inserts the node created into the list.
373 - The \ref key_type should be constructible from value of type \p K.
374 In trivial case, \p K is equal to \ref key_type.
375 - The \ref mapped_type should be default-constructible.
377 Returns \p true if inserting successful, \p false otherwise.
379 template <typename K>
380 bool insert( const K& key )
382 return insert_at( head(), key );
385 /// Inserts new node with a key and a value
387 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
390 - The \ref key_type should be constructible from \p key of type \p K.
391 - The \ref mapped_type should be constructible from \p val of type \p V.
393 Returns \p true if inserting successful, \p false otherwise.
395 template <typename K, typename V>
396 bool insert( const K& key, const V& val )
398 // We cannot use insert with functor here
399 // because we cannot lock inserted node for updating
400 // Therefore, we use separate function
401 return insert_at( head(), key, val );
404 /// Inserts new node and initializes it by a functor
406 This function inserts new node with key \p key and if inserting is successful then it calls
407 \p func functor with signature
410 void operator()( value_type& item );
414 The argument \p item of user-defined functor \p func is the reference
415 to the list's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
416 User-defined functor \p func should guarantee that during changing item's value no any other changes
417 could be made on this list's item by concurrent threads.
418 The user-defined functor can be passed by reference using \p std::ref
419 and it is called only if inserting is successful.
421 The key_type should be constructible from value of type \p K.
423 The function allows to split creating of new item into two part:
424 - create item from \p key;
425 - insert new item into the list;
426 - if inserting is successful, initialize the value of item by calling \p func functor
428 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
429 it is preferable that the initialization should be completed only if inserting is successful.
431 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
433 template <typename K, typename Func>
434 bool insert_key( const K& key, Func func )
436 return insert_key_at( head(), key, func );
439 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
441 Returns \p true if inserting successful, \p false otherwise.
443 template <typename... Args>
444 bool emplace( Args&&... args )
446 return emplace_at( head(), std::forward<Args>(args)... );
449 /// Ensures that the \p key exists in the list
451 The operation performs inserting or changing data with lock-free manner.
453 If the \p key not found in the list, then the new item created from \p key
454 is inserted into the list (note that in this case the \ref key_type should be
455 copy-constructible from type \p K).
456 Otherwise, the functor \p func is called with item found.
457 The functor \p Func may be a function with signature:
459 void func( bool bNew, value_type& item );
464 void operator()( bool bNew, value_type& item );
469 - \p bNew - \p true if the item has been inserted, \p false otherwise
470 - \p item - item of the list
472 The functor may change any fields of the \p item.second that is \ref mapped_type;
473 however, \p func must guarantee that during changing no any other modifications
474 could be made on this item by concurrent threads.
476 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
477 \p second is true if new item has been added or \p false if the item with \p key
478 already is in the list.
480 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
482 template <typename K, typename Func>
483 std::pair<bool, bool> ensure( const K& key, Func f )
485 return ensure_at( head(), key, f );
488 /// Deletes \p key from the list
489 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_val
491 Returns \p true if \p key is found and has been deleted, \p false otherwise
493 template <typename K>
494 bool erase( K const& key )
496 return erase_at( head(), key, intrusive_key_comparator() );
499 /// Deletes the item from the list using \p pred predicate for searching
501 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_val "erase(K const&)"
502 but \p pred is used for key comparing.
503 \p Less functor has the interface like \p std::less.
504 \p pred must imply the same element order as the comparator used for building the list.
506 template <typename K, typename Less>
507 bool erase_with( K const& key, Less pred )
509 return erase_at( head(), key, typename options::template less_wrapper<Less>::type() );
512 /// Deletes \p key from the list
513 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_func
514 The function searches an item with key \p key, calls \p f functor with item found
515 and deletes it. If \p key is not found, the functor is not called.
517 The functor \p Func interface:
520 void operator()(value_type& val) { ... }
523 The functor may be passed by reference with <tt>boost:ref</tt>
525 Returns \p true if key is found and deleted, \p false otherwise
527 template <typename K, typename Func>
528 bool erase( K const& key, Func f )
530 return erase_at( head(), key, intrusive_key_comparator(), f );
533 /// Deletes the item from the list using \p pred predicate for searching
535 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_func "erase(K const&, Func)"
536 but \p pred is used for key comparing.
537 \p Less functor has the interface like \p std::less.
538 \p pred must imply the same element order as the comparator used for building the list.
540 template <typename K, typename Less, typename Func>
541 bool erase_with( K const& key, Less pred, Func f )
543 return erase_at( head(), key, typename options::template less_wrapper<Less>::type(), f );
546 /// Extracts the item from the list with specified \p key
547 /** \anchor cds_nonintrusive_LazyKVList_hp_extract
548 The function searches an item with key equal to \p key,
549 unlinks it from the list, and returns it in \p dest parameter.
550 If the item with key equal to \p key is not found the function returns \p false.
552 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
554 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
558 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
562 ord_list::guarded_ptr gp;
563 theList.extract( gp, 5 );
567 // Destructor of gp releases internal HP guard and frees the item
571 template <typename K>
572 bool extract( guarded_ptr& dest, K const& key )
574 return extract_at( head(), dest.guard(), key, intrusive_key_comparator() );
577 /// Extracts the item from the list with comparing functor \p pred
579 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_extract "extract(guarded_ptr&, K const&)"
580 but \p pred predicate is used for key comparing.
582 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
584 \p pred must imply the same element order as the comparator used for building the list.
586 template <typename K, typename Less>
587 bool extract_with( guarded_ptr& dest, K const& key, Less pred )
589 return extract_at( head(), dest.guard(), key, typename options::template less_wrapper<Less>::type() );
592 /// Finds the key \p key
593 /** \anchor cds_nonintrusive_LazyKVList_hp_find_val
594 The function searches the item with key equal to \p key
595 and returns \p true if it is found, and \p false otherwise
597 template <typename Q>
598 bool find( Q const& key )
600 return find_at( head(), key, intrusive_key_comparator() );
603 /// Finds the key \p val using \p pred predicate for searching
605 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_find_val "find(Q const&)"
606 but \p pred is used for key comparing.
607 \p Less functor has the interface like \p std::less.
608 \p pred must imply the same element order as the comparator used for building the list.
610 template <typename Q, typename Less>
611 bool find_with( Q const& key, Less pred )
613 return find_at( head(), key, typename options::template less_wrapper<Less>::type() );
616 /// Finds the key \p key and performs an action with it
617 /** \anchor cds_nonintrusive_LazyKVList_hp_find_func
618 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
619 The interface of \p Func functor is:
622 void operator()( value_type& item );
625 where \p item is the item found.
627 You may pass \p f argument by reference using \p std::ref.
629 The functor may change <tt>item.second</tt> that is reference to value of node.
630 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
631 The function does not serialize simultaneous access to the list \p item. If such access is
632 possible you must provide your own synchronization schema to exclude unsafe item modifications.
634 The function returns \p true if \p key is found, \p false otherwise.
636 template <typename Q, typename Func>
637 bool find( Q const& key, Func f )
639 return find_at( head(), key, intrusive_key_comparator(), f );
642 /// Finds the key \p val using \p pred predicate for searching
644 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_find_func "find(Q&, Func)"
645 but \p pred is used for key comparing.
646 \p Less functor has the interface like \p std::less.
647 \p pred must imply the same element order as the comparator used for building the list.
649 template <typename Q, typename Less, typename Func>
650 bool find_with( Q const& key, Less pred, Func f )
652 return find_at( head(), key, typename options::template less_wrapper<Less>::type(), f );
655 /// Finds \p key and return the item found
656 /** \anchor cds_nonintrusive_LazyKVList_hp_get
657 The function searches the item with key equal to \p key
658 and assigns the item found to guarded pointer \p ptr.
659 The function returns \p true if \p key is found, and \p false otherwise.
660 If \p key is not found the \p ptr parameter is not changed.
662 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
666 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
670 ord_list::guarded_ptr gp;
671 if ( theList.get( gp, 5 )) {
675 // Destructor of guarded_ptr releases internal HP guard and frees the item
679 Note the compare functor specified for class \p Traits template parameter
680 should accept a parameter of type \p K that can be not the same as \p key_type.
682 template <typename K>
683 bool get( guarded_ptr& ptr, K const& key )
685 return get_at( head(), ptr.guard(), key, intrusive_key_comparator() );
688 /// Finds the key \p val and return the item found
690 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_get "get(guarded_ptr& ptr, K const&)"
691 but \p pred is used for comparing the keys.
693 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
695 \p pred must imply the same element order as the comparator used for building the list.
697 template <typename K, typename Less>
698 bool get_with( guarded_ptr& ptr, K const& key, Less pred )
700 return get_at( head(), ptr.guard(), key, typename options::template less_wrapper<Less>::type() );
703 /// Checks if the list is empty
706 return base_class::empty();
709 /// Returns list's item count
711 The value returned depends on opt::item_counter option. For atomicity::empty_item_counter,
712 this function always returns 0.
714 <b>Warning</b>: even if you use real item counter and it returns 0, this fact is not mean that the list
715 is empty. To check list emptyness use \ref empty() method.
719 return base_class::size();
724 Post-condition: the list is empty
733 bool insert_node_at( head_type& refHead, node_type * pNode )
735 assert( pNode != nullptr );
736 scoped_node_ptr p( pNode );
738 if ( base_class::insert_at( &refHead, *p )) {
746 template <typename K>
747 bool insert_at( head_type& refHead, const K& key )
749 return insert_node_at( refHead, alloc_node( key ));
752 template <typename K, typename V>
753 bool insert_at( head_type& refHead, const K& key, const V& val )
755 return insert_node_at( refHead, alloc_node( key, val ));
758 template <typename K, typename Func>
759 bool insert_key_at( head_type& refHead, const K& key, Func f )
761 scoped_node_ptr pNode( alloc_node( key ));
763 if ( base_class::insert_at( &refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); } )) {
770 template <typename... Args>
771 bool emplace_at( head_type& refHead, Args&&... args )
773 return insert_node_at( refHead, alloc_node( std::forward<Args>(args)... ));
776 template <typename K, typename Compare>
777 bool erase_at( head_type& refHead, K const& key, Compare cmp )
779 return base_class::erase_at( &refHead, key, cmp );
782 template <typename K, typename Compare, typename Func>
783 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
785 return base_class::erase_at( &refHead, key, cmp, [&f](node_type const & node){f( const_cast<value_type&>(node.m_Data)); });
788 template <typename K, typename Compare>
789 bool extract_at( head_type& refHead, typename gc::Guard& dest, K const& key, Compare cmp )
791 return base_class::extract_at( &refHead, dest, key, cmp );
794 template <typename K, typename Func>
795 std::pair<bool, bool> ensure_at( head_type& refHead, const K& key, Func f )
797 scoped_node_ptr pNode( alloc_node( key ));
799 std::pair<bool, bool> ret = base_class::ensure_at( &refHead, *pNode,
800 [&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 gc::Guard& guard, K const& key, Compare cmp )
822 return base_class::get_at( &refHead, guard, key, cmp );
828 }} // namespace cds::container
830 #endif // #ifndef __CDS_CONTAINER_IMPL_LAZY_KVLIST_H