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::PTB: \code #include <cds/container/lazy_kvlist_ptb.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 template <typename K, typename Func>
432 bool insert_key( const K& key, Func func )
434 return insert_key_at( head(), key, func );
437 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
439 Returns \p true if inserting successful, \p false otherwise.
441 template <typename... Args>
442 bool emplace( Args&&... args )
444 return emplace_at( head(), std::forward<Args>(args)... );
447 /// Ensures that the \p key exists in the list
449 The operation performs inserting or changing data with lock-free manner.
451 If the \p key not found in the list, then the new item created from \p key
452 is inserted into the list (note that in this case the \ref key_type should be
453 copy-constructible from type \p K).
454 Otherwise, the functor \p func is called with item found.
455 The functor \p Func may be a function with signature:
457 void func( bool bNew, value_type& item );
462 void operator()( bool bNew, value_type& item );
467 - \p bNew - \p true if the item has been inserted, \p false otherwise
468 - \p item - item of the list
470 The functor may change any fields of the \p item.second that is \ref mapped_type;
471 however, \p func must guarantee that during changing no any other modifications
472 could be made on this item by concurrent threads.
474 You may pass \p func argument by reference using \p std::ref.
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 template <typename K, typename Func>
481 std::pair<bool, bool> ensure( const K& key, Func f )
483 return ensure_at( head(), key, f );
486 /// Deletes \p key from the list
487 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_val
489 Returns \p true if \p key is found and has been deleted, \p false otherwise
491 template <typename K>
492 bool erase( K const& key )
494 return erase_at( head(), key, intrusive_key_comparator() );
497 /// Deletes the item from the list using \p pred predicate for searching
499 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_val "erase(K const&)"
500 but \p pred is used for key comparing.
501 \p Less functor has the interface like \p std::less.
502 \p pred must imply the same element order as the comparator used for building the list.
504 template <typename K, typename Less>
505 bool erase_with( K const& key, Less pred )
507 return erase_at( head(), key, typename options::template less_wrapper<Less>::type() );
510 /// Deletes \p key from the list
511 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_func
512 The function searches an item with key \p key, calls \p f functor with item found
513 and deletes it. If \p key is not found, the functor is not called.
515 The functor \p Func interface:
518 void operator()(value_type& val) { ... }
521 The functor may be passed by reference with <tt>boost:ref</tt>
523 Returns \p true if key is found and deleted, \p false otherwise
525 template <typename K, typename Func>
526 bool erase( K const& key, Func f )
528 return erase_at( head(), key, intrusive_key_comparator(), f );
531 /// Deletes the item from the list using \p pred predicate for searching
533 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_func "erase(K const&, Func)"
534 but \p pred is used for key comparing.
535 \p Less functor has the interface like \p std::less.
536 \p pred must imply the same element order as the comparator used for building the list.
538 template <typename K, typename Less, typename Func>
539 bool erase_with( K const& key, Less pred, Func f )
541 return erase_at( head(), key, typename options::template less_wrapper<Less>::type(), f );
544 /// Extracts the item from the list with specified \p key
545 /** \anchor cds_nonintrusive_LazyKVList_hp_extract
546 The function searches an item with key equal to \p key,
547 unlinks it from the list, and returns it in \p dest parameter.
548 If the item with key equal to \p key is not found the function returns \p false.
550 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
552 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
556 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
560 ord_list::guarded_ptr gp;
561 theList.extract( gp, 5 );
565 // Destructor of gp releases internal HP guard and frees the item
569 template <typename K>
570 bool extract( guarded_ptr& dest, K const& key )
572 return extract_at( head(), dest.guard(), key, intrusive_key_comparator() );
575 /// Extracts the item from the list with comparing functor \p pred
577 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_extract "extract(guarded_ptr&, K const&)"
578 but \p pred predicate is used for key comparing.
580 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
582 \p pred must imply the same element order as the comparator used for building the list.
584 template <typename K, typename Less>
585 bool extract_with( guarded_ptr& dest, K const& key, Less pred )
587 return extract_at( head(), dest.guard(), key, typename options::template less_wrapper<Less>::type() );
590 /// Finds the key \p key
591 /** \anchor cds_nonintrusive_LazyKVList_hp_find_val
592 The function searches the item with key equal to \p key
593 and returns \p true if it is found, and \p false otherwise
595 template <typename Q>
596 bool find( Q const& key )
598 return find_at( head(), key, intrusive_key_comparator() );
601 /// Finds the key \p val using \p pred predicate for searching
603 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_find_val "find(Q const&)"
604 but \p pred is used for key comparing.
605 \p Less functor has the interface like \p std::less.
606 \p pred must imply the same element order as the comparator used for building the list.
608 template <typename Q, typename Less>
609 bool find_with( Q const& key, Less pred )
611 return find_at( head(), key, typename options::template less_wrapper<Less>::type() );
614 /// Finds the key \p key and performs an action with it
615 /** \anchor cds_nonintrusive_LazyKVList_hp_find_func
616 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
617 The interface of \p Func functor is:
620 void operator()( value_type& item );
623 where \p item is the item found.
625 You may pass \p f argument by reference using \p std::ref.
627 The functor may change <tt>item.second</tt> that is reference to value of node.
628 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
629 The function does not serialize simultaneous access to the list \p item. If such access is
630 possible you must provide your own synchronization schema to exclude unsafe item modifications.
632 The function returns \p true if \p key is found, \p false otherwise.
634 template <typename Q, typename Func>
635 bool find( Q const& key, Func f )
637 return find_at( head(), key, intrusive_key_comparator(), f );
640 /// Finds the key \p val using \p pred predicate for searching
642 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_find_func "find(Q&, Func)"
643 but \p pred is used for key comparing.
644 \p Less functor has the interface like \p std::less.
645 \p pred must imply the same element order as the comparator used for building the list.
647 template <typename Q, typename Less, typename Func>
648 bool find_with( Q const& key, Less pred, Func f )
650 return find_at( head(), key, typename options::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 assigns the item found to guarded pointer \p ptr.
657 The function returns \p true if \p key is found, and \p false otherwise.
658 If \p key is not found the \p ptr parameter is not changed.
660 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
664 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
668 ord_list::guarded_ptr gp;
669 if ( theList.get( gp, 5 )) {
673 // Destructor of guarded_ptr releases internal HP guard and frees the item
677 Note the compare functor specified for class \p Traits template parameter
678 should accept a parameter of type \p K that can be not the same as \p key_type.
680 template <typename K>
681 bool get( guarded_ptr& ptr, K const& key )
683 return get_at( head(), ptr.guard(), key, intrusive_key_comparator() );
686 /// Finds the key \p val and return the item found
688 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_get "get(guarded_ptr& ptr, K const&)"
689 but \p pred is used for comparing the keys.
691 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
693 \p pred must imply the same element order as the comparator used for building the list.
695 template <typename K, typename Less>
696 bool get_with( guarded_ptr& ptr, K const& key, Less pred )
698 return get_at( head(), ptr.guard(), key, typename options::template less_wrapper<Less>::type() );
701 /// Checks if the list is empty
704 return base_class::empty();
707 /// Returns list's item count
709 The value returned depends on opt::item_counter option. For atomicity::empty_item_counter,
710 this function always returns 0.
712 <b>Warning</b>: even if you use real item counter and it returns 0, this fact is not mean that the list
713 is empty. To check list emptyness use \ref empty() method.
717 return base_class::size();
722 Post-condition: the list is empty
731 bool insert_node_at( head_type& refHead, node_type * pNode )
733 assert( pNode != nullptr );
734 scoped_node_ptr p( pNode );
736 if ( base_class::insert_at( &refHead, *p )) {
744 template <typename K>
745 bool insert_at( head_type& refHead, const K& key )
747 return insert_node_at( refHead, alloc_node( key ));
750 template <typename K, typename V>
751 bool insert_at( head_type& refHead, const K& key, const V& val )
753 return insert_node_at( refHead, alloc_node( key, val ));
756 template <typename K, typename Func>
757 bool insert_key_at( head_type& refHead, const K& key, Func f )
759 scoped_node_ptr pNode( alloc_node( key ));
761 if ( base_class::insert_at( &refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); } )) {
768 template <typename... Args>
769 bool emplace_at( head_type& refHead, Args&&... args )
771 return insert_node_at( refHead, alloc_node( std::forward<Args>(args)... ));
774 template <typename K, typename Compare>
775 bool erase_at( head_type& refHead, K const& key, Compare cmp )
777 return base_class::erase_at( &refHead, key, cmp );
780 template <typename K, typename Compare, typename Func>
781 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
783 return base_class::erase_at( &refHead, key, cmp, [&f](node_type const & node){f( const_cast<value_type&>(node.m_Data)); });
786 template <typename K, typename Compare>
787 bool extract_at( head_type& refHead, typename gc::Guard& dest, K const& key, Compare cmp )
789 return base_class::extract_at( &refHead, dest, key, cmp );
792 template <typename K, typename Func>
793 std::pair<bool, bool> ensure_at( head_type& refHead, const K& key, Func f )
795 scoped_node_ptr pNode( alloc_node( key ));
797 std::pair<bool, bool> ret = base_class::ensure_at( &refHead, *pNode,
798 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); });
799 if ( ret.first && ret.second )
805 template <typename K, typename Compare>
806 bool find_at( head_type& refHead, K const& key, Compare cmp )
808 return base_class::find_at( &refHead, key, cmp );
811 template <typename K, typename Compare, typename Func>
812 bool find_at( head_type& refHead, K& key, Compare cmp, Func f )
814 return base_class::find_at( &refHead, key, cmp, [&f]( node_type& node, K& ){ f( node.m_Data ); });
817 template <typename K, typename Compare>
818 bool get_at( head_type& refHead, typename gc::Guard& guard, K const& key, Compare cmp )
820 return base_class::get_at( &refHead, guard, key, cmp );
826 }} // namespace cds::container
828 #endif // #ifndef __CDS_CONTAINER_IMPL_LAZY_KVLIST_H