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
139 typedef typename base_class::value_type node_type;
140 typedef typename maker::cxx_allocator cxx_allocator;
141 typedef typename maker::node_deallocator node_deallocator;
142 typedef typename maker::intrusive_traits::compare intrusive_key_comparator;
144 typedef typename base_class::node_type head_type;
149 typedef typename gc::template guarded_ptr< node_type, value_type, details::guarded_ptr_cast_map<node_type, value_type> > guarded_ptr;
153 template <typename K>
154 static node_type * alloc_node(const K& key)
156 return cxx_allocator().New( key );
159 template <typename K, typename V>
160 static node_type * alloc_node( const K& key, const V& val )
162 return cxx_allocator().New( key, val );
165 template <typename... Args>
166 static node_type * alloc_node( Args&&... args )
168 return cxx_allocator().MoveNew( std::forward<Args>(args)... );
171 static void free_node( node_type * pNode )
173 cxx_allocator().Delete( pNode );
176 struct node_disposer {
177 void operator()( node_type * pNode )
182 typedef std::unique_ptr< node_type, node_disposer > scoped_node_ptr;
186 return base_class::m_Head;
189 head_type const& head() const
191 return base_class::m_Head;
196 return base_class::m_Tail;
199 head_type const& tail() const
201 return base_class::m_Tail;
208 template <bool IsConst>
209 class iterator_type: protected base_class::template iterator_type<IsConst>
211 typedef typename base_class::template iterator_type<IsConst> iterator_base;
213 iterator_type( head_type const& pNode )
214 : iterator_base( const_cast<head_type *>(&pNode) )
216 iterator_type( head_type const * pNode )
217 : iterator_base( const_cast<head_type *>(pNode) )
220 friend class LazyKVList;
223 typedef typename cds::details::make_const_type<mapped_type, IsConst>::reference value_ref;
224 typedef typename cds::details::make_const_type<mapped_type, IsConst>::pointer value_ptr;
226 typedef typename cds::details::make_const_type<value_type, IsConst>::reference pair_ref;
227 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer pair_ptr;
232 iterator_type( iterator_type const& src )
233 : iterator_base( src )
236 key_type const& key() const
238 typename iterator_base::value_ptr p = iterator_base::operator ->();
239 assert( p != nullptr );
240 return p->m_Data.first;
243 value_ref val() const
245 typename iterator_base::value_ptr p = iterator_base::operator ->();
246 assert( p != nullptr );
247 return p->m_Data.second;
250 pair_ptr operator ->() const
252 typename iterator_base::value_ptr p = iterator_base::operator ->();
253 return p ? &(p->m_Data) : nullptr;
256 pair_ref operator *() const
258 typename iterator_base::value_ref p = iterator_base::operator *();
263 iterator_type& operator ++()
265 iterator_base::operator ++();
270 bool operator ==(iterator_type<C> const& i ) const
272 return iterator_base::operator ==(i);
275 bool operator !=(iterator_type<C> const& i ) const
277 return iterator_base::operator !=(i);
285 The forward iterator for lazy list has some features:
286 - it has no post-increment operator
287 - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
288 For some GC (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
289 may be thrown if a limit of guard count per thread is exceeded.
290 - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
291 - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
292 deleting operations it is no guarantee that you iterate all item in the list.
294 Therefore, the use of iterators in concurrent environment is not good idea. Use the iterator on the concurrent container
295 for debug purpose only.
297 The iterator interface to access item data:
298 - <tt> operator -> </tt> - returns a pointer to \ref value_type for iterator
299 - <tt> operator *</tt> - returns a reference (a const reference for \p const_iterator) to \ref value_type for iterator
300 - <tt> const key_type& key() </tt> - returns a key reference for iterator
301 - <tt> mapped_type& val() </tt> - retuns a value reference for iterator (const reference for \p const_iterator)
303 For both functions the iterator should not be equal to <tt> end() </tt>
305 typedef iterator_type<false> iterator;
307 /// Const forward iterator
309 For iterator's features and requirements see \ref iterator
311 typedef iterator_type<true> const_iterator;
313 /// Returns a forward iterator addressing the first element in a list
315 For empty list \code begin() == end() \endcode
319 iterator it( head() );
320 ++it ; // skip dummy head
324 /// Returns an iterator that addresses the location succeeding the last element in a list
326 Do not use the value returned by <tt>end</tt> function to access any item.
327 Internally, <tt>end</tt> returning value equals to \p nullptr.
329 The returned value can be used only to control reaching the end of the list.
330 For empty list \code begin() == end() \endcode
334 return iterator( tail() );
337 /// Returns a forward const iterator addressing the first element in a list
339 const_iterator begin() const
341 const_iterator it( head() );
342 ++it; // skip dummy head
345 const_iterator cbegin() const
347 const_iterator it( head() );
348 ++it; // skip dummy head
353 /// Returns an const iterator that addresses the location succeeding the last element in a list
355 const_iterator end() const
357 return const_iterator( tail());
359 const_iterator cend() const
361 return const_iterator( tail());
366 /// Default constructor
370 /// Destructor clears the list
376 /// Inserts new node with key and default value
378 The function creates a node with \p key and default value, and then inserts the node created into the list.
381 - The \ref key_type should be constructible from value of type \p K.
382 In trivial case, \p K is equal to \ref key_type.
383 - The \ref mapped_type should be default-constructible.
385 Returns \p true if inserting successful, \p false otherwise.
387 template <typename K>
388 bool insert( const K& key )
390 return insert_at( head(), key );
393 /// Inserts new node with a key and a value
395 The function creates a node with \p key and value \p val, and then inserts the node created into the list.
398 - The \ref key_type should be constructible from \p key of type \p K.
399 - The \ref mapped_type should be constructible from \p val of type \p V.
401 Returns \p true if inserting successful, \p false otherwise.
403 template <typename K, typename V>
404 bool insert( const K& key, const V& val )
406 // We cannot use insert with functor here
407 // because we cannot lock inserted node for updating
408 // Therefore, we use separate function
409 return insert_at( head(), key, val );
412 /// Inserts new node and initializes it by a functor
414 This function inserts new node with key \p key and if inserting is successful then it calls
415 \p func functor with signature
418 void operator()( value_type& item );
422 The argument \p item of user-defined functor \p func is the reference
423 to the list's item inserted. <tt>item.second</tt> is a reference to item's value that may be changed.
424 The user-defined functor is called only if inserting is successful.
426 The \p key_type should be constructible from value of type \p K.
428 The function allows to split creating of new item into two part:
429 - create item from \p key;
430 - insert new item into the list;
431 - if inserting is successful, initialize the value of item by calling \p func functor
433 This can be useful if complete initialization of object of \p mapped_type is heavyweight and
434 it is preferable that the initialization should be completed only if inserting is successful.
436 template <typename K, typename Func>
437 bool insert_with( const K& key, Func func )
439 return insert_with_at( head(), key, func );
442 /// Inserts data of type \ref mapped_type constructed with <tt>std::forward<Args>(args)...</tt>
444 Returns \p true if inserting successful, \p false otherwise.
446 template <typename... Args>
447 bool emplace( Args&&... args )
449 return emplace_at( head(), std::forward<Args>(args)... );
452 /// Updates data by \p key
454 The operation performs inserting or replacing the element with lock-free manner.
456 If the \p key not found in the list, then the new item created from \p key
457 will be inserted iff \p bAllowInsert is \p true.
458 (note that in this case the \ref key_type should be constructible from type \p K).
459 Otherwise, if \p key is found, the functor \p func is called with item found.
461 The functor \p Func signature is:
464 void operator()( bool bNew, value_type& item );
468 - \p bNew - \p true if the item has been inserted, \p false otherwise
469 - \p item - the item found or inserted
471 The functor may change any fields of the \p item.second of \p mapped_type;
472 during \p func call \p item is locked so it is safe to modify the item in
473 multi-threaded environment.
475 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
476 \p second is true if new item has been added or \p false if the item with \p key
479 template <typename K, typename Func>
480 std::pair<bool, bool> update( const K& key, Func f, bool bAllowInsert = true )
482 return update_at( head(), key, f, bAllowInsert );
485 template <typename K, typename Func>
486 CDS_DEPRECATED("ensure() is deprecated, use update()")
487 std::pair<bool, bool> ensure( const K& key, Func f )
489 return update( key, f, true );
493 /// Deletes \p key from the list
494 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_val
496 Returns \p true if \p key is found and has been deleted, \p false otherwise
498 template <typename K>
499 bool erase( K const& key )
501 return erase_at( head(), key, intrusive_key_comparator() );
504 /// Deletes the item from the list using \p pred predicate for searching
506 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_val "erase(K const&)"
507 but \p pred is used for key comparing.
508 \p Less functor has the interface like \p std::less.
509 \p pred must imply the same element order as the comparator used for building the list.
511 template <typename K, typename Less>
512 bool erase_with( K const& key, Less pred )
515 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type() );
518 /// Deletes \p key from the list
519 /** \anchor cds_nonintrusive_LazyKVList_hp_erase_func
520 The function searches an item with key \p key, calls \p f functor with item found
521 and deletes it. If \p key is not found, the functor is not called.
523 The functor \p Func interface:
526 void operator()(value_type& val) { ... }
530 Returns \p true if key is found and deleted, \p false otherwise
532 template <typename K, typename Func>
533 bool erase( K const& key, Func f )
535 return erase_at( head(), key, intrusive_key_comparator(), f );
538 /// Deletes the item from the list using \p pred predicate for searching
540 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_erase_func "erase(K const&, Func)"
541 but \p pred is used for key comparing.
542 \p Less functor has the interface like \p std::less.
543 \p pred must imply the same element order as the comparator used for building the list.
545 template <typename K, typename Less, typename Func>
546 bool erase_with( K const& key, Less pred, Func f )
549 return erase_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
552 /// Extracts the item from the list with specified \p key
553 /** \anchor cds_nonintrusive_LazyKVList_hp_extract
554 The function searches an item with key equal to \p key,
555 unlinks it from the list, and returns it as \p guarded_ptr.
556 If \p key is not found the function returns an empty guarded pointer.
558 Note the compare functor should accept a parameter of type \p K that can be not the same as \p key_type.
560 @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
564 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
568 ord_list::guarded_ptr gp( theList.extract( 5 ));
573 // Destructor of gp releases internal HP guard and frees the item
577 template <typename K>
578 guarded_ptr extract( K const& key )
581 extract_at( head(), gp.guard(), key, intrusive_key_comparator() );
585 /// Extracts the item from the list with comparing functor \p pred
587 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_extract "extract(K const&)"
588 but \p pred predicate is used for key comparing.
590 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
592 \p pred must imply the same element order as the comparator used for building the list.
594 template <typename K, typename Less>
595 guarded_ptr extract_with( K const& key, Less pred )
599 extract_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
603 /// Checks whether the list contains \p key
605 The function searches the item with key equal to \p key
606 and returns \p true if it is found, and \p false otherwise.
608 template <typename Q>
609 bool contains( Q const& key )
611 return find_at( head(), key, intrusive_key_comparator() );
614 template <typename Q>
615 CDS_DEPRECATED("deprecated, use contains()")
616 bool find( Q const& key )
618 return contains( key );
622 /// Checks whether the map contains \p key using \p pred predicate for searching
624 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
625 \p Less functor has the interface like \p std::less.
626 \p Less must imply the same element order as the comparator used for building the list.
628 template <typename Q, typename Less>
629 bool contains( Q const& key, Less pred )
632 return find_at( head(), key, typename maker::template less_wrapper<Less>::type() );
635 template <typename Q, typename Less>
636 CDS_DEPRECATED("deprecated, use contains()")
637 bool find_with( Q const& key, Less pred )
639 return contains( key, pred );
643 /// Finds the key \p key and performs an action with it
644 /** \anchor cds_nonintrusive_LazyKVList_hp_find_func
645 The function searches an item with key equal to \p key and calls the functor \p f for the item found.
646 The interface of \p Func functor is:
649 void operator()( value_type& item );
652 where \p item is the item found.
654 The functor may change <tt>item.second</tt> that is reference to value of node.
655 Note that the function is only guarantee that \p item cannot be deleted during functor is executing.
656 The function does not serialize simultaneous access to the list \p item. If such access is
657 possible you must provide your own synchronization schema to exclude unsafe item modifications.
659 The function returns \p true if \p key is found, \p false otherwise.
661 template <typename Q, typename Func>
662 bool find( Q const& key, Func f )
664 return find_at( head(), key, intrusive_key_comparator(), f );
667 /// Finds the key \p val using \p pred predicate for searching
669 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_find_func "find(Q&, Func)"
670 but \p pred is used for key comparing.
671 \p Less functor has the interface like \p std::less.
672 \p pred must imply the same element order as the comparator used for building the list.
674 template <typename Q, typename Less, typename Func>
675 bool find_with( Q const& key, Less pred, Func f )
678 return find_at( head(), key, typename maker::template less_wrapper<Less>::type(), f );
681 /// Finds \p key and return the item found
682 /** \anchor cds_nonintrusive_LazyKVList_hp_get
683 The function searches the item with key equal to \p key
684 and returns the item found as a guarded pointer.
685 If \p key is not found the functions returns an empty \p guarded_ptr.
687 @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
691 typedef cds::container::LazyKVList< cds::gc::HP, int, foo, my_traits > ord_list;
695 ord_list::guarded_ptr gp( theList.get( 5 ));
700 // Destructor of guarded_ptr releases internal HP guard and frees the item
704 Note the compare functor specified for class \p Traits template parameter
705 should accept a parameter of type \p K that can be not the same as \p key_type.
707 template <typename K>
708 guarded_ptr get( K const& key )
711 get_at( head(), gp.guard(), key, intrusive_key_comparator() );
715 /// Finds the key \p val and return the item found
717 The function is an analog of \ref cds_nonintrusive_LazyKVList_hp_get "get(K const&)"
718 but \p pred is used for comparing the keys.
720 \p Less functor has the semantics like \p std::less but should take arguments of type \ref key_type and \p K
722 \p pred must imply the same element order as the comparator used for building the list.
724 template <typename K, typename Less>
725 guarded_ptr get_with( K const& key, Less pred )
729 get_at( head(), gp.guard(), key, typename maker::template less_wrapper<Less>::type() );
733 /// Checks if the list is empty
736 return base_class::empty();
739 /// Returns list's item count
741 The value returned depends on opt::item_counter option. For atomicity::empty_item_counter,
742 this function always returns 0.
744 @note Even if you use real item counter and it returns 0, this fact is not mean that the list
745 is empty. To check list emptyness use \ref empty() method.
749 return base_class::size();
760 bool insert_node_at( head_type& refHead, node_type * pNode )
762 assert( pNode != nullptr );
763 scoped_node_ptr p( pNode );
765 if ( base_class::insert_at( &refHead, *p )) {
773 template <typename K>
774 bool insert_at( head_type& refHead, const K& key )
776 return insert_node_at( refHead, alloc_node( key ));
779 template <typename K, typename V>
780 bool insert_at( head_type& refHead, const K& key, const V& val )
782 return insert_node_at( refHead, alloc_node( key, val ));
785 template <typename K, typename Func>
786 bool insert_with_at( head_type& refHead, const K& key, Func f )
788 scoped_node_ptr pNode( alloc_node( key ));
790 if ( base_class::insert_at( &refHead, *pNode, [&f](node_type& node){ f( node.m_Data ); } )) {
797 template <typename... Args>
798 bool emplace_at( head_type& refHead, Args&&... args )
800 return insert_node_at( refHead, alloc_node( std::forward<Args>(args)... ));
803 template <typename K, typename Compare>
804 bool erase_at( head_type& refHead, K const& key, Compare cmp )
806 return base_class::erase_at( &refHead, key, cmp );
809 template <typename K, typename Compare, typename Func>
810 bool erase_at( head_type& refHead, K const& key, Compare cmp, Func f )
812 return base_class::erase_at( &refHead, key, cmp, [&f](node_type const & node){f( const_cast<value_type&>(node.m_Data)); });
815 template <typename K, typename Compare>
816 bool extract_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
818 return base_class::extract_at( &refHead, guard, key, cmp );
821 template <typename K, typename Func>
822 std::pair<bool, bool> update_at( head_type& refHead, const K& key, Func f, bool bAllowInsert )
824 scoped_node_ptr pNode( alloc_node( key ));
826 std::pair<bool, bool> ret = base_class::update_at( &refHead, *pNode,
827 [&f]( bool bNew, node_type& node, node_type& ){ f( bNew, node.m_Data ); },
829 if ( ret.first && ret.second )
835 template <typename K, typename Compare>
836 bool find_at( head_type& refHead, K const& key, Compare cmp )
838 return base_class::find_at( &refHead, key, cmp );
841 template <typename K, typename Compare, typename Func>
842 bool find_at( head_type& refHead, K& key, Compare cmp, Func f )
844 return base_class::find_at( &refHead, key, cmp, [&f]( node_type& node, K& ){ f( node.m_Data ); });
847 template <typename K, typename Compare>
848 bool get_at( head_type& refHead, typename guarded_ptr::native_guard& guard, K const& key, Compare cmp )
850 return base_class::get_at( &refHead, guard, key, cmp );
856 }} // namespace cds::container
858 #endif // #ifndef CDSLIB_CONTAINER_IMPL_LAZY_KVLIST_H