2 This file is a part of libcds - Concurrent Data Structures library
4 (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
6 Source code repo: http://github.com/khizmax/libcds/
7 Download: http://sourceforge.net/projects/libcds/files/
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31 #ifndef CDSLIB_CONTAINER_IMPL_LAZY_KVLIST_H
32 #define CDSLIB_CONTAINER_IMPL_LAZY_KVLIST_H
35 #include <cds/container/details/guarded_ptr_cast.h>
37 namespace cds { namespace container {
39 /// Lazy ordered list (key-value pair)
40 /** @ingroup cds_nonintrusive_list
41 \anchor cds_nonintrusive_LazyKVList_gc
43 This is key-value variation of non-intrusive LazyList.
44 Like standard container, this implementation split a value stored into two part -
45 constant key and alterable value.
47 Usually, ordered single-linked list is used as a building block for the hash table implementation.
48 The complexity of searching is <tt>O(N)</tt>.
51 - \p GC - garbage collector
52 - \p Key - key type of an item to be stored in the list. It should be copy-constructible
53 - \p Value - value type to be stored in the list
54 - \p Traits - type traits, default is \p lazy_list::traits
55 It is possible to declare option-based list with cds::container::lazy_list::make_traits metafunction istead of \p Traits template
56 argument. For example, the following traits-based declaration of \p gc::HP lazy list
58 #include <cds/container/lazy_kvlist_hp.h>
59 // Declare comparator for the item
61 int operator ()( int i1, int i2 )
68 struct my_traits: public cds::container::lazy_list::traits
70 typedef my_compare compare;
73 // Declare traits-based list
74 typedef cds::container::LazyKVList< cds::gc::HP, int, int, my_traits > traits_based_list;
76 is equal to the following option-based list
78 #include <cds/container/lazy_kvlist_hp.h>
80 // my_compare is the same
82 // Declare option-based list
83 typedef cds::container::LazyKVList< cds::gc::HP, int, int,
84 typename cds::container::lazy_list::make_traits<
85 cds::container::opt::compare< my_compare > // item comparator option
91 There are different specializations of this template for each garbage collecting schema used.
92 You should include appropriate .h-file depending on GC you are using:
93 - for \p gc::HP: <tt> <cds/container/lazy_kvlist_hp.h> </tt>
94 - for \p gc::DHP: <tt> <cds/container/lazy_kvlist_dhp.h> </tt>
95 - for \ref cds_urcu_desc "RCU": <tt> <cds/container/lazy_kvlist_rcu.h> </tt>
96 - for \p gc::nogc: <tt> <cds/container/lazy_kvlist_nogc.h> </tt>
102 #ifdef CDS_DOXYGEN_INVOKED
103 typename Traits = lazy_list::traits
109 #ifdef CDS_DOXYGEN_INVOKED
110 protected intrusive::LazyList< GC, implementation_defined, Traits >
112 protected details::make_lazy_kvlist< GC, Key, Value, Traits >::type
116 typedef details::make_lazy_kvlist< GC, Key, Value, Traits > maker;
117 typedef typename maker::type base_class;
121 typedef GC gc; ///< Garbage collector
122 #ifdef CDS_DOXYGEN_INVOKED
123 typedef Key key_type ; ///< Key type
124 typedef Value mapped_type ; ///< Type of value stored in the list
125 typedef std::pair<key_type const, mapped_type> value_type ; ///< key/value pair stored in the list
127 typedef typename maker::key_type key_type;
128 typedef typename maker::mapped_type mapped_type;
129 typedef typename maker::value_type value_type;
131 typedef typename base_class::back_off back_off; ///< Back-off strategy
132 typedef typename maker::allocator_type allocator_type; ///< Allocator type used for allocate/deallocate the nodes
133 typedef typename base_class::item_counter item_counter; ///< Item counter type
134 typedef typename maker::key_comparator key_comparator; ///< key comparing functor
135 typedef typename base_class::memory_model memory_model; ///< Memory ordering. See \p cds::opt::memory_model
136 typedef typename base_class::stat stat; ///< Internal statistics
138 static CDS_CONSTEXPR const size_t c_nHazardPtrCount = base_class::c_nHazardPtrCount; ///< Count of hazard pointer required for the algorithm
142 typedef typename base_class::value_type node_type;
143 typedef typename maker::cxx_allocator cxx_allocator;
144 typedef typename maker::node_deallocator node_deallocator;
145 typedef typename maker::intrusive_traits::compare intrusive_key_comparator;
147 typedef typename base_class::node_type head_type;
152 typedef typename gc::template guarded_ptr< node_type, value_type, details::guarded_ptr_cast_map<node_type, value_type> > guarded_ptr;
156 template <typename K>
157 static node_type * alloc_node(const K& key)
159 return cxx_allocator().New( key );
162 template <typename K, typename V>
163 static node_type * alloc_node( const K& key, const V& val )
165 return cxx_allocator().New( key, val );
168 template <typename... Args>
169 static node_type * alloc_node( Args&&... args )
171 return cxx_allocator().MoveNew( std::forward<Args>(args)... );
174 static void free_node( node_type * pNode )
176 cxx_allocator().Delete( pNode );
179 struct node_disposer {
180 void operator()( node_type * pNode )
185 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
189 return base_class::m_Head;
192 head_type const& head() const
194 return base_class::m_Head;
199 return base_class::m_Tail;
202 head_type const& tail() const
204 return base_class::m_Tail;
211 template <bool IsConst>
212 class iterator_type: protected base_class::template iterator_type<IsConst>
214 typedef typename base_class::template iterator_type<IsConst> iterator_base;
216 iterator_type( head_type const& pNode )
217 : iterator_base( const_cast<head_type *>(&pNode) )
219 iterator_type( head_type const * pNode )
220 : iterator_base( const_cast<head_type *>(pNode) )
223 friend class LazyKVList;
226 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
227 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
229 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
230 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
235 iterator_type( iterator_type const& src )
236 : iterator_base( src )
239 key_type const& key() const
241 typename iterator_base::value_ptr p = iterator_base::operator ->();
242 assert( p != nullptr );
243 return p->m_Data.first;
246 value_ref val() const
248 typename iterator_base::value_ptr p = iterator_base::operator ->();
249 assert( p != nullptr );
250 return p->m_Data.second;
253 pair_ptr operator ->() const
255 typename iterator_base::value_ptr p = iterator_base::operator ->();
256 return p ? &(p->m_Data) : nullptr;
259 pair_ref operator *() const
261 typename iterator_base::value_ref p = iterator_base::operator *();
266 iterator_type& operator ++()
268 iterator_base::operator ++();
273 bool operator ==(iterator_type<C> const& i ) const
275 return iterator_base::operator ==(i);
278 bool operator !=(iterator_type<C> const& i ) const
280 return iterator_base::operator !=(i);
288 The forward iterator for lazy list has some features:
289 - it has no post-increment operator
290 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
291 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
292 may be thrown if a limit of guard count per thread is exceeded.
293 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
294 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
295 deleting operations it is no guarantee that you iterate all item in the list.
297 @warning Use this iterator on the concurrent container for debugging purpose only.
299 The iterator interface to access item data:
300 - <tt> operator -> </tt> - returns a pointer to \ref value_type for iterator
301 - <tt> operator *</tt> - returns a reference (a const reference for \p const_iterator) to \ref value_type for iterator
302 - <tt> const key_type& key() </tt> - returns a key reference for iterator
303 - <tt> mapped_type& val() </tt> - retuns a value reference for iterator (const reference for \p const_iterator)
305 For both functions the iterator should not be equal to <tt> end() </tt>
307 typedef iterator_type<false> iterator;
309 /// Const forward iterator
311 For iterator's features and requirements see \ref iterator
313 typedef iterator_type<true> const_iterator;
315 ///@name Forward iterators (only for debugging purpose)
317 /// Returns a forward iterator addressing the first element in a list
319 For empty list \code begin() == end() \endcode
323 iterator it( head() );
324 ++it ; // skip dummy head
328 /// Returns an iterator that addresses the location succeeding the last element in a list
330 Do not use the value returned by <tt>end</tt> function to access any item.
331 Internally, <tt>end</tt> returning value equals to \p nullptr.
333 The returned value can be used only to control reaching the end of the list.
334 For empty list \code begin() == end() \endcode
338 return iterator( tail() );
341 /// Returns a forward const iterator addressing the first element in a list
342 const_iterator begin() const
344 const_iterator it( head() );
345 ++it; // skip dummy head
349 /// Returns a forward const iterator addressing the first element in a list
350 const_iterator cbegin() const
352 const_iterator it( head() );
353 ++it; // skip dummy head
357 /// Returns an const iterator that addresses the location succeeding the last element in a list
358 const_iterator end() const
360 return const_iterator( tail());
363 /// Returns an const iterator that addresses the location succeeding the last element in a list
364 const_iterator cend() const
366 return const_iterator( tail());
371 /// Default constructor
376 template <typename Stat, typename = std::enable_if<std::is_same<stat, lazy_list::wrapped_stat<Stat>>::value >>
377 explicit LazyKVList( Stat& st )
382 /// Destructor clears the list
388 /// Inserts new node with key and default value
390 The function creates a node with \p key and default value, and then inserts the node created into the list.
393 - The \ref key_type should be constructible from value of type \p K.
394 In trivial case, \p K is equal to \ref key_type.
395 - The \ref mapped_type should be default-constructible.
397 Returns \p true if inserting successful, \p false otherwise.
399 template <typename K>
400 bool insert( const K& key )
402 return insert_at( head(), key );
405 /// Inserts new node with a key and a value
407 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
410 - The \ref key_type should be constructible from \p key of type \p K.
411 - The \ref mapped_type should be constructible from \p val of type \p V.
413 Returns \p true if inserting successful, \p false otherwise.
415 template <typename K, typename V>
416 bool insert( const K& key, const V& val )
418 // We cannot use insert with functor here
419 // because we cannot lock inserted node for updating
420 // Therefore, we use separate function
421 return insert_at( head(), key, val );
424 /// Inserts new node and initializes it by a functor
426 This function inserts new node with key \p key and if inserting is successful then it calls
427 \p func functor with signature
430 void operator()( value_type& item );
434 The argument \p item of user-defined functor \p func is the reference
435 to the list's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
436 The user-defined functor is called only if inserting is successful.
438 The \p key_type should be constructible from value of type \p K.
440 The function allows to split creating of new item into two part:
441 - create item from \p key;
442 - insert new item into the list;
443 - if inserting is successful, initialize the value of item by calling \p func functor
445 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
446 it is preferable that the initialization should be completed only if inserting is successful.
448 template <typename K, typename Func>
449 bool insert_with( const K& key, Func func )
451 return insert_with_at( head(), key, func );
454 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
456 Returns \p true if inserting successful, \p false otherwise.
458 template <typename... Args>
459 bool emplace( Args&&... args )
461 return emplace_at( head(), std::forward<Args>(args)... );
464 /// Updates data by \p key
466 The operation performs inserting or replacing the element with lock-free manner.
468 If the \p key not found in the list, then the new item created from \p key
469 will be inserted iff \p bAllowInsert is \p true.
470 (note that in this case the \ref key_type should be constructible from type \p K).
471 Otherwise, if \p key is found, the functor \p func is called with item found.
473 The functor \p Func signature is:
476 void operator()( bool bNew, value_type& item );
480 - \p bNew - \p true if the item has been inserted, \p false otherwise
481 - \p item - the item found or inserted
483 The functor may change any fields of the \p item.second of \p mapped_type;
484 during \p func call \p item is locked so it is safe to modify the item in
485 multi-threaded environment.
487 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successful,
488 \p second is true if new item has been added or \p false if the item with \p key
491 template <typename K, typename Func>
492 std::pair<bool, bool> update( const K& key, Func f, bool bAllowInsert = true )
494 return update_at( head(), key, f, bAllowInsert );
497 template <typename K, typename Func>
498 CDS_DEPRECATED("ensure() is deprecated, use update()")
499 std::pair<bool, bool> ensure( const K& key, Func f )
501 return update( key, f, true );
505 /// Deletes \p key from the list
506 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_val
508 Returns \p true if \p key is found and has been deleted, \p false otherwise
510 template <typename K>
511 bool erase( K const& key )
513 return erase_at( head(), key, intrusive_key_comparator() );
516 /// Deletes the item from the list using \p pred predicate for searching
518 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_val "erase(K const&)"
519 but \p pred is used for key comparing.
520 \p Less functor has the interface like \p std::less.
521 \p pred must imply the same element order as the comparator used for building the list.
523 template <typename K, typename Less>
524 bool erase_with( K const& key, Less pred )
527 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
530 /// Deletes \p key from the list
531 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_func
532 The function searches an item with key \p key, calls \p f functor with item found
533 and deletes it. If \p key is not found, the functor is not called.
535 The functor \p Func interface:
538 void operator()(value_type& val) { ... }
542 Returns \p true if key is found and deleted, \p false otherwise
544 template <typename K, typename Func>
545 bool erase( K const& key, Func f )
547 return erase_at( head(), key, intrusive_key_comparator(), f );
550 /// Deletes the item from the list using \p pred predicate for searching
552 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_func "erase(K const&, Func)"
553 but \p pred is used for key comparing.
554 \p Less functor has the interface like \p std::less.
555 \p pred must imply the same element order as the comparator used for building the list.
557 template <typename K, typename Less, typename Func>
558 bool erase_with( K const& key, Less pred, Func f )
561 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
564 /// Extracts the item from the list with specified \p key
565 /** \anchor cds_nonintrusive_LazyKVList_hp_extract
566 The function searches an item with key equal to \p key,
567 unlinks it from the list, and returns it as \p guarded_ptr.
568 If \p key is not found the function returns an empty guarded pointer.
570 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
572 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
576 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
580 ord_list::guarded_ptr gp( theList.extract( 5 ));
585 // Destructor of gp releases internal HP guard and frees the item
589 template <typename K>
590 guarded_ptr extract( K const& key )
593 extract_at( head(), gp.guard(), key, intrusive_key_comparator() );
597 /// Extracts the item from the list with comparing functor \p pred
599 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_extract "extract(K const&)"
600 but \p pred predicate is used for key comparing.
602 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
604 \p pred must imply the same element order as the comparator used for building the list.
606 template <typename K, typename Less>
607 guarded_ptr extract_with( K const& key, Less pred )
611 extract_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
615 /// Checks whether the list contains \p key
617 The function searches the item with key equal to \p key
618 and returns \p true if it is found, and \p false otherwise.
620 template <typename Q>
621 bool contains( Q const& key )
623 return find_at( head(), key, intrusive_key_comparator() );
626 template <typename Q>
627 CDS_DEPRECATED("deprecated, use contains()")
628 bool find( Q const& key )
630 return contains( key );
634 /// Checks whether the map contains \p key using \p pred predicate for searching
636 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
637 \p Less functor has the interface like \p std::less.
638 \p Less must imply the same element order as the comparator used for building the list.
640 template <typename Q, typename Less>
641 bool contains( Q const& key, Less pred )
644 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
647 template <typename Q, typename Less>
648 CDS_DEPRECATED("deprecated, use contains()")
649 bool find_with( Q const& key, Less pred )
651 return contains( key, pred );
655 /// Finds the key \p key and performs an action with it
656 /** \anchor cds_nonintrusive_LazyKVList_hp_find_func
657 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
658 The interface of \p Func functor is:
661 void operator()( value_type& item );
664 where \p item is the item found.
666 The functor may change <tt>item.second</tt> that is reference to value of node.
667 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
668 The function does not serialize simultaneous access to the list \p item. If such access is
669 possible you must provide your own synchronization schema to exclude unsafe item modifications.
671 The function returns \p true if \p key is found, \p false otherwise.
673 template <typename Q, typename Func>
674 bool find( Q const& key, Func f )
676 return find_at( head(), key, intrusive_key_comparator(), f );
679 /// Finds the key \p val using \p pred predicate for searching
681 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_find_func "find(Q&, Func)"
682 but \p pred is used for key comparing.
683 \p Less functor has the interface like \p std::less.
684 \p pred must imply the same element order as the comparator used for building the list.
686 template <typename Q, typename Less, typename Func>
687 bool find_with( Q const& key, Less pred, Func f )
690 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
693 /// Finds \p key and return the item found
694 /** \anchor cds_nonintrusive_LazyKVList_hp_get
695 The function searches the item with key equal to \p key
696 and returns the item found as a guarded pointer.
697 If \p key is not found the functions returns an empty \p guarded_ptr.
699 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
703 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
707 ord_list::guarded_ptr gp( theList.get( 5 ));
712 // Destructor of guarded_ptr releases internal HP guard and frees the item
716 Note the compare functor specified for class \p Traits template parameter
717 should accept a parameter of type \p K that can be not the same as \p key_type.
719 template <typename K>
720 guarded_ptr get( K const& key )
723 get_at( head(), gp.guard(), key, intrusive_key_comparator() );
727 /// Finds the key \p val and return the item found
729 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_get "get(K const&)"
730 but \p pred is used for comparing the keys.
732 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
734 \p pred must imply the same element order as the comparator used for building the list.
736 template <typename K, typename Less>
737 guarded_ptr get_with( K const& key, Less pred )
741 get_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
745 /// Checks if the list is empty
748 return base_class::empty();
751 /// Returns list's item count
753 The value returned depends on opt::item_counter option. For atomicity::empty_item_counter,
754 this function always returns 0.
756 @note Even if you use real item counter and it returns 0, this fact is not mean that the list
757 is empty. To check list emptyness use \ref empty() method.
761 return base_class::size();
764 /// Returns const reference to internal statistics
765 stat const& statistics() const
767 return base_class::statistics();
778 bool insert_node_at( head_type& refHead, node_type * pNode )
780 assert( pNode != nullptr );
781 scoped_node_ptr p( pNode );
783 if ( base_class::insert_at( &refHead, *p )) {
791 template <typename K>
792 bool insert_at( head_type& refHead, const K& key )
794 return insert_node_at( refHead, alloc_node( key ));
797 template <typename K, typename V>
798 bool insert_at( head_type& refHead, const K& key, const V& val )
800 return insert_node_at( refHead, alloc_node( key, val ));
803 template <typename K, typename Func>
804 bool insert_with_at( head_type& refHead, const K& key, Func f )
806 scoped_node_ptr pNode( alloc_node( key ));
808 if ( base_class::insert_at( &refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); } )) {
815 template <typename... Args>
816 bool emplace_at( head_type& refHead, Args&&... args )
818 return insert_node_at( refHead, alloc_node( std::forward<Args>(args)... ));
821 template <typename K, typename Compare>
822 bool erase_at( head_type& refHead, K const& key, Compare cmp )
824 return base_class::erase_at( &refHead, key, cmp );
827 template <typename K, typename Compare, typename Func>
828 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
830 return base_class::erase_at( &refHead, key, cmp, [&f](node_type const & node){f( const_cast<value_type&>(node.m_Data)); });
833 template <typename K, typename Compare>
834 bool extract_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
836 return base_class::extract_at( &refHead, guard, key, cmp );
839 template <typename K, typename Func>
840 std::pair<bool, bool> update_at( head_type& refHead, const K& key, Func f, bool bAllowInsert )
842 scoped_node_ptr pNode( alloc_node( key ));
844 std::pair<bool, bool> ret = base_class::update_at( &refHead, *pNode,
845 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); },
847 if ( ret.first && ret.second )
853 template <typename K, typename Compare>
854 bool find_at( head_type& refHead, K const& key, Compare cmp )
856 return base_class::find_at( &refHead, key, cmp );
859 template <typename K, typename Compare, typename Func>
860 bool find_at( head_type& refHead, K& key, Compare cmp, Func f )
862 return base_class::find_at( &refHead, key, cmp, [&f]( node_type& node, K& ){ f( node.m_Data ); });
865 template <typename K, typename Compare>
866 bool get_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
868 return base_class::get_at( &refHead, guard, key, cmp );
874 }} // namespace cds::container
876 #endif // #ifndef CDSLIB_CONTAINER_IMPL_LAZY_KVLIST_H