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
137 static CDS_CONSTEXPR const size_t c_nHazardPtrCount = base_class::c_nHazardPtrCount; ///< Count of hazard pointer required for the algorithm
141 typedef typename base_class::value_type node_type;
142 typedef typename maker::cxx_allocator cxx_allocator;
143 typedef typename maker::node_deallocator node_deallocator;
144 typedef typename maker::intrusive_traits::compare intrusive_key_comparator;
146 typedef typename base_class::node_type head_type;
151 typedef typename gc::template guarded_ptr< node_type, value_type, details::guarded_ptr_cast_map<node_type, value_type> > guarded_ptr;
155 template <typename K>
156 static node_type * alloc_node(const K& key)
158 return cxx_allocator().New( key );
161 template <typename K, typename V>
162 static node_type * alloc_node( const K& key, const V& val )
164 return cxx_allocator().New( key, val );
167 template <typename... Args>
168 static node_type * alloc_node( Args&&... args )
170 return cxx_allocator().MoveNew( std::forward<Args>(args)... );
173 static void free_node( node_type * pNode )
175 cxx_allocator().Delete( pNode );
178 struct node_disposer {
179 void operator()( node_type * pNode )
184 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
188 return base_class::m_Head;
191 head_type const& head() const
193 return base_class::m_Head;
198 return base_class::m_Tail;
201 head_type const& tail() const
203 return base_class::m_Tail;
210 template <bool IsConst>
211 class iterator_type: protected base_class::template iterator_type<IsConst>
213 typedef typename base_class::template iterator_type<IsConst> iterator_base;
215 iterator_type( head_type const& pNode )
216 : iterator_base( const_cast<head_type *>(&pNode) )
218 iterator_type( head_type const * pNode )
219 : iterator_base( const_cast<head_type *>(pNode) )
222 friend class LazyKVList;
225 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
226 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
228 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
229 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
234 iterator_type( iterator_type const& src )
235 : iterator_base( src )
238 key_type const& key() const
240 typename iterator_base::value_ptr p = iterator_base::operator ->();
241 assert( p != nullptr );
242 return p->m_Data.first;
245 value_ref val() const
247 typename iterator_base::value_ptr p = iterator_base::operator ->();
248 assert( p != nullptr );
249 return p->m_Data.second;
252 pair_ptr operator ->() const
254 typename iterator_base::value_ptr p = iterator_base::operator ->();
255 return p ? &(p->m_Data) : nullptr;
258 pair_ref operator *() const
260 typename iterator_base::value_ref p = iterator_base::operator *();
265 iterator_type& operator ++()
267 iterator_base::operator ++();
272 bool operator ==(iterator_type<C> const& i ) const
274 return iterator_base::operator ==(i);
277 bool operator !=(iterator_type<C> const& i ) const
279 return iterator_base::operator !=(i);
287 The forward iterator for lazy list has some features:
288 - it has no post-increment operator
289 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
290 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
291 may be thrown if a limit of guard count per thread is exceeded.
292 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
293 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
294 deleting operations it is no guarantee that you iterate all item in the list.
296 @warning Use this iterator on the concurrent container for debugging purpose only.
298 The iterator interface to access item data:
299 - <tt> operator -> </tt> - returns a pointer to \ref value_type for iterator
300 - <tt> operator *</tt> - returns a reference (a const reference for \p const_iterator) to \ref value_type for iterator
301 - <tt> const key_type& key() </tt> - returns a key reference for iterator
302 - <tt> mapped_type& val() </tt> - retuns a value reference for iterator (const reference for \p const_iterator)
304 For both functions the iterator should not be equal to <tt> end() </tt>
306 typedef iterator_type<false> iterator;
308 /// Const forward iterator
310 For iterator's features and requirements see \ref iterator
312 typedef iterator_type<true> const_iterator;
314 ///@name Forward iterators (only for debugging purpose)
316 /// Returns a forward iterator addressing the first element in a list
318 For empty list \code begin() == end() \endcode
322 iterator it( head() );
323 ++it ; // skip dummy head
327 /// Returns an iterator that addresses the location succeeding the last element in a list
329 Do not use the value returned by <tt>end</tt> function to access any item.
330 Internally, <tt>end</tt> returning value equals to \p nullptr.
332 The returned value can be used only to control reaching the end of the list.
333 For empty list \code begin() == end() \endcode
337 return iterator( tail() );
340 /// Returns a forward const iterator addressing the first element in a list
341 const_iterator begin() const
343 const_iterator it( head() );
344 ++it; // skip dummy head
348 /// Returns a forward const iterator addressing the first element in a list
349 const_iterator cbegin() const
351 const_iterator it( head() );
352 ++it; // skip dummy head
356 /// Returns an const iterator that addresses the location succeeding the last element in a list
357 const_iterator end() const
359 return const_iterator( tail());
362 /// Returns an const iterator that addresses the location succeeding the last element in a list
363 const_iterator cend() const
365 return const_iterator( tail());
370 /// Default constructor
374 /// Destructor clears the list
380 /// Inserts new node with key and default value
382 The function creates a node with \p key and default value, and then inserts the node created into the list.
385 - The \ref key_type should be constructible from value of type \p K.
386 In trivial case, \p K is equal to \ref key_type.
387 - The \ref mapped_type should be default-constructible.
389 Returns \p true if inserting successful, \p false otherwise.
391 template <typename K>
392 bool insert( const K& key )
394 return insert_at( head(), key );
397 /// Inserts new node with a key and a value
399 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
402 - The \ref key_type should be constructible from \p key of type \p K.
403 - The \ref mapped_type should be constructible from \p val of type \p V.
405 Returns \p true if inserting successful, \p false otherwise.
407 template <typename K, typename V>
408 bool insert( const K& key, const V& val )
410 // We cannot use insert with functor here
411 // because we cannot lock inserted node for updating
412 // Therefore, we use separate function
413 return insert_at( head(), key, val );
416 /// Inserts new node and initializes it by a functor
418 This function inserts new node with key \p key and if inserting is successful then it calls
419 \p func functor with signature
422 void operator()( value_type& item );
426 The argument \p item of user-defined functor \p func is the reference
427 to the list's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
428 The user-defined functor is called only if inserting is successful.
430 The \p key_type should be constructible from value of type \p K.
432 The function allows to split creating of new item into two part:
433 - create item from \p key;
434 - insert new item into the list;
435 - if inserting is successful, initialize the value of item by calling \p func functor
437 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
438 it is preferable that the initialization should be completed only if inserting is successful.
440 template <typename K, typename Func>
441 bool insert_with( const K& key, Func func )
443 return insert_with_at( head(), key, func );
446 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
448 Returns \p true if inserting successful, \p false otherwise.
450 template <typename... Args>
451 bool emplace( Args&&... args )
453 return emplace_at( head(), std::forward<Args>(args)... );
456 /// Updates data by \p key
458 The operation performs inserting or replacing the element with lock-free manner.
460 If the \p key not found in the list, then the new item created from \p key
461 will be inserted iff \p bAllowInsert is \p true.
462 (note that in this case the \ref key_type should be constructible from type \p K).
463 Otherwise, if \p key is found, the functor \p func is called with item found.
465 The functor \p Func signature is:
468 void operator()( bool bNew, value_type& item );
472 - \p bNew - \p true if the item has been inserted, \p false otherwise
473 - \p item - the item found or inserted
475 The functor may change any fields of the \p item.second of \p mapped_type;
476 during \p func call \p item is locked so it is safe to modify the item in
477 multi-threaded environment.
479 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
480 \p second is true if new item has been added or \p false if the item with \p key
483 template <typename K, typename Func>
484 std::pair<bool, bool> update( const K& key, Func f, bool bAllowInsert = true )
486 return update_at( head(), key, f, bAllowInsert );
489 template <typename K, typename Func>
490 CDS_DEPRECATED("ensure() is deprecated, use update()")
491 std::pair<bool, bool> ensure( const K& key, Func f )
493 return update( key, f, true );
497 /// Deletes \p key from the list
498 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_val
500 Returns \p true if \p key is found and has been deleted, \p false otherwise
502 template <typename K>
503 bool erase( K const& key )
505 return erase_at( head(), key, intrusive_key_comparator() );
508 /// Deletes the item from the list using \p pred predicate for searching
510 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_val "erase(K const&)"
511 but \p pred is used for key comparing.
512 \p Less functor has the interface like \p std::less.
513 \p pred must imply the same element order as the comparator used for building the list.
515 template <typename K, typename Less>
516 bool erase_with( K const& key, Less pred )
519 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
522 /// Deletes \p key from the list
523 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_func
524 The function searches an item with key \p key, calls \p f functor with item found
525 and deletes it. If \p key is not found, the functor is not called.
527 The functor \p Func interface:
530 void operator()(value_type& val) { ... }
534 Returns \p true if key is found and deleted, \p false otherwise
536 template <typename K, typename Func>
537 bool erase( K const& key, Func f )
539 return erase_at( head(), key, intrusive_key_comparator(), f );
542 /// Deletes the item from the list using \p pred predicate for searching
544 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_func "erase(K const&, Func)"
545 but \p pred is used for key comparing.
546 \p Less functor has the interface like \p std::less.
547 \p pred must imply the same element order as the comparator used for building the list.
549 template <typename K, typename Less, typename Func>
550 bool erase_with( K const& key, Less pred, Func f )
553 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
556 /// Extracts the item from the list with specified \p key
557 /** \anchor cds_nonintrusive_LazyKVList_hp_extract
558 The function searches an item with key equal to \p key,
559 unlinks it from the list, and returns it as \p guarded_ptr.
560 If \p key is not found the function returns an empty guarded pointer.
562 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
564 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
568 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
572 ord_list::guarded_ptr gp( theList.extract( 5 ));
577 // Destructor of gp releases internal HP guard and frees the item
581 template <typename K>
582 guarded_ptr extract( K const& key )
585 extract_at( head(), gp.guard(), key, intrusive_key_comparator() );
589 /// Extracts the item from the list with comparing functor \p pred
591 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_extract "extract(K const&)"
592 but \p pred predicate is used for key comparing.
594 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
596 \p pred must imply the same element order as the comparator used for building the list.
598 template <typename K, typename Less>
599 guarded_ptr extract_with( K const& key, Less pred )
603 extract_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
607 /// Checks whether the list contains \p key
609 The function searches the item with key equal to \p key
610 and returns \p true if it is found, and \p false otherwise.
612 template <typename Q>
613 bool contains( Q const& key )
615 return find_at( head(), key, intrusive_key_comparator() );
618 template <typename Q>
619 CDS_DEPRECATED("deprecated, use contains()")
620 bool find( Q const& key )
622 return contains( key );
626 /// Checks whether the map contains \p key using \p pred predicate for searching
628 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
629 \p Less functor has the interface like \p std::less.
630 \p Less must imply the same element order as the comparator used for building the list.
632 template <typename Q, typename Less>
633 bool contains( Q const& key, Less pred )
636 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
639 template <typename Q, typename Less>
640 CDS_DEPRECATED("deprecated, use contains()")
641 bool find_with( Q const& key, Less pred )
643 return contains( key, pred );
647 /// Finds the key \p key and performs an action with it
648 /** \anchor cds_nonintrusive_LazyKVList_hp_find_func
649 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
650 The interface of \p Func functor is:
653 void operator()( value_type& item );
656 where \p item is the item found.
658 The functor may change <tt>item.second</tt> that is reference to value of node.
659 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
660 The function does not serialize simultaneous access to the list \p item. If such access is
661 possible you must provide your own synchronization schema to exclude unsafe item modifications.
663 The function returns \p true if \p key is found, \p false otherwise.
665 template <typename Q, typename Func>
666 bool find( Q const& key, Func f )
668 return find_at( head(), key, intrusive_key_comparator(), f );
671 /// Finds the key \p val using \p pred predicate for searching
673 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_find_func "find(Q&, Func)"
674 but \p pred is used for key comparing.
675 \p Less functor has the interface like \p std::less.
676 \p pred must imply the same element order as the comparator used for building the list.
678 template <typename Q, typename Less, typename Func>
679 bool find_with( Q const& key, Less pred, Func f )
682 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
685 /// Finds \p key and return the item found
686 /** \anchor cds_nonintrusive_LazyKVList_hp_get
687 The function searches the item with key equal to \p key
688 and returns the item found as a guarded pointer.
689 If \p key is not found the functions returns an empty \p guarded_ptr.
691 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
695 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
699 ord_list::guarded_ptr gp( theList.get( 5 ));
704 // Destructor of guarded_ptr releases internal HP guard and frees the item
708 Note the compare functor specified for class \p Traits template parameter
709 should accept a parameter of type \p K that can be not the same as \p key_type.
711 template <typename K>
712 guarded_ptr get( K const& key )
715 get_at( head(), gp.guard(), key, intrusive_key_comparator() );
719 /// Finds the key \p val and return the item found
721 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_get "get(K const&)"
722 but \p pred is used for comparing the keys.
724 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
726 \p pred must imply the same element order as the comparator used for building the list.
728 template <typename K, typename Less>
729 guarded_ptr get_with( K const& key, Less pred )
733 get_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
737 /// Checks if the list is empty
740 return base_class::empty();
743 /// Returns list's item count
745 The value returned depends on opt::item_counter option. For atomicity::empty_item_counter,
746 this function always returns 0.
748 @note Even if you use real item counter and it returns 0, this fact is not mean that the list
749 is empty. To check list emptyness use \ref empty() method.
753 return base_class::size();
764 bool insert_node_at( head_type& refHead, node_type * pNode )
766 assert( pNode != nullptr );
767 scoped_node_ptr p( pNode );
769 if ( base_class::insert_at( &refHead, *p )) {
777 template <typename K>
778 bool insert_at( head_type& refHead, const K& key )
780 return insert_node_at( refHead, alloc_node( key ));
783 template <typename K, typename V>
784 bool insert_at( head_type& refHead, const K& key, const V& val )
786 return insert_node_at( refHead, alloc_node( key, val ));
789 template <typename K, typename Func>
790 bool insert_with_at( head_type& refHead, const K& key, Func f )
792 scoped_node_ptr pNode( alloc_node( key ));
794 if ( base_class::insert_at( &refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); } )) {
801 template <typename... Args>
802 bool emplace_at( head_type& refHead, Args&&... args )
804 return insert_node_at( refHead, alloc_node( std::forward<Args>(args)... ));
807 template <typename K, typename Compare>
808 bool erase_at( head_type& refHead, K const& key, Compare cmp )
810 return base_class::erase_at( &refHead, key, cmp );
813 template <typename K, typename Compare, typename Func>
814 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
816 return base_class::erase_at( &refHead, key, cmp, [&f](node_type const & node){f( const_cast<value_type&>(node.m_Data)); });
819 template <typename K, typename Compare>
820 bool extract_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
822 return base_class::extract_at( &refHead, guard, key, cmp );
825 template <typename K, typename Func>
826 std::pair<bool, bool> update_at( head_type& refHead, const K& key, Func f, bool bAllowInsert )
828 scoped_node_ptr pNode( alloc_node( key ));
830 std::pair<bool, bool> ret = base_class::update_at( &refHead, *pNode,
831 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); },
833 if ( ret.first && ret.second )
839 template <typename K, typename Compare>
840 bool find_at( head_type& refHead, K const& key, Compare cmp )
842 return base_class::find_at( &refHead, key, cmp );
845 template <typename K, typename Compare, typename Func>
846 bool find_at( head_type& refHead, K& key, Compare cmp, Func f )
848 return base_class::find_at( &refHead, key, cmp, [&f]( node_type& node, K& ){ f( node.m_Data ); });
851 template <typename K, typename Compare>
852 bool get_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
854 return base_class::get_at( &refHead, guard, key, cmp );
860 }} // namespace cds::container
862 #endif // #ifndef CDSLIB_CONTAINER_IMPL_LAZY_KVLIST_H