3 #ifndef __CDS_CONTAINER_ELLEN_BINTREE_MAP_RCU_H
4 #define __CDS_CONTAINER_ELLEN_BINTREE_MAP_RCU_H
6 #include <cds/container/ellen_bintree_base.h>
7 #include <cds/intrusive/ellen_bintree_rcu.h>
8 #include <cds/details/functor_wrapper.h>
10 namespace cds { namespace container {
12 /// Map based on Ellen's et al binary search tree (RCU specialization)
13 /** @ingroup cds_nonintrusive_map
14 @ingroup cds_nonintrusive_tree
15 @anchor cds_container_EllenBinTreeMap_rcu
18 - [2010] F.Ellen, P.Fatourou, E.Ruppert, F.van Breugel "Non-blocking Binary Search Tree"
20 %EllenBinTreeMap is an unbalanced leaf-oriented binary search tree that implements the <i>map</i>
21 abstract data type. Nodes maintains child pointers but not parent pointers.
22 Every internal node has exactly two children, and all data of type <tt>std::pair<Key const, T></tt>
23 currently in the tree are stored in the leaves. Internal nodes of the tree are used to direct \p find
24 operation along the path to the correct leaf. The keys (of \p Key type) stored in internal nodes
25 may or may not be in the map.
26 Unlike \ref cds_container_EllenBinTreeSet_rcu "EllenBinTreeSet" keys are not a part of \p T type.
27 The map can be represented as a set containing <tt>std::pair< Key const, T> </tt> values.
29 Due to \p extract_min and \p extract_max member functions the \p %EllenBinTreeMap can act as
30 a <i>priority queue</i>. In this case you should provide unique compound key, for example,
31 the priority value plus some uniformly distributed random value.
33 @warning Recall the tree is <b>unbalanced</b>. The complexity of operations is <tt>O(log N)</tt>
34 for uniformly distributed random keys, but in worst case the complexity is <tt>O(N)</tt>.
36 @note In the current implementation we do not use helping technique described in original paper.
37 So, the current implementation is near to fine-grained lock-based tree.
38 Helping will be implemented in future release
40 <b>Template arguments</b> :
41 - \p RCU - one of \ref cds_urcu_gc "RCU type"
43 - \p T - value type to be stored in tree's leaf nodes.
44 - \p Traits - type traits. See ellen_bintree::type_traits for explanation.
46 It is possible to declare option-based tree with ellen_bintree::make_map_traits metafunction
47 instead of \p Traits template argument.
48 Template argument list \p Options of ellen_bintree::make_map_traits metafunction are:
49 - opt::compare - key compare functor. No default functor is provided.
50 If the option is not specified, \p %opt::less is used.
51 - opt::less - specifies binary predicate used for key compare. At least \p %opt::compare or \p %opt::less should be defined.
52 - opt::item_counter - the type of item counting feature. Default is \ref atomicity::empty_item_counter that is no item counting.
53 - opt::memory_model - C++ memory ordering model. Can be opt::v::relaxed_ordering (relaxed memory model, the default)
54 or opt::v::sequential_consistent (sequentially consisnent memory model).
55 - opt::allocator - the allocator used for \ref ellen_bintree::map_node "leaf nodes" which contains data.
56 Default is \ref CDS_DEFAULT_ALLOCATOR.
57 - opt::node_allocator - the allocator used for \ref ellen_bintree::internal_node "internal nodes".
58 Default is \ref CDS_DEFAULT_ALLOCATOR.
59 - ellen_bintree::update_desc_allocator - an allocator of \ref ellen_bintree::update_desc "update descriptors",
60 default is \ref CDS_DEFAULT_ALLOCATOR.
61 Note that update descriptor is helping data structure with short lifetime and it is good candidate for pooling.
62 The number of simultaneously existing descriptors is a relatively small number limited the number of threads
63 working with the tree and RCU buffer size.
64 Therefore, a bounded lock-free container like \p cds::container::VyukovMPMCCycleQueue is good choice for the free-list
65 of update descriptors, see cds::memory::vyukov_queue_pool free-list implementation.
66 Also notice that size of update descriptor is not dependent on the type of data
67 stored in the tree so single free-list object can be used for several EllenBinTree-based object.
68 - opt::stat - internal statistics. Available types: ellen_bintree::stat, ellen_bintree::empty_stat (the default)
69 - opt::rcu_check_deadlock - a deadlock checking policy. Default is opt::v::rcu_throw_deadlock
70 - opt::copy_policy - key copy policy defines a functor to copy leaf node's key to internal node.
71 By default, assignment operator is used.
72 The copy functor interface is:
75 void operator()( Key& dest, Key const& src );
79 @note Before including <tt><cds/container/ellen_bintree_map_rcu.h></tt> you should include appropriate RCU header file,
80 see \ref cds_urcu_gc "RCU type" for list of existing RCU class and corresponding header files.
86 #ifdef CDS_DOXYGEN_INVOKED
87 class Traits = ellen_bintree::type_traits
92 class EllenBinTreeMap< cds::urcu::gc<RCU>, Key, T, Traits >
93 #ifdef CDS_DOXYGEN_INVOKED
94 : public cds::intrusive::EllenBinTree< cds::urcu::gc<RCU>, Key, T, Traits >
96 : public ellen_bintree::details::make_ellen_bintree_map< cds::urcu::gc<RCU>, Key, T, Traits >::type
100 typedef ellen_bintree::details::make_ellen_bintree_map< cds::urcu::gc<RCU>, Key, T, Traits > maker;
101 typedef typename maker::type base_class;
104 typedef cds::urcu::gc<RCU> gc ; ///< RCU Garbage collector
105 typedef Key key_type ; ///< type of a key stored in the map
106 typedef T mapped_type ; ///< type of value stored in the map
107 typedef std::pair< key_type const, mapped_type > value_type ; ///< Key-value pair stored in leaf node of the mp
108 typedef Traits options ; ///< Traits template parameter
110 # ifdef CDS_DOXYGEN_INVOKED
111 typedef implementation_defined key_comparator ; ///< key compare functor based on opt::compare and opt::less option setter.
113 typedef typename maker::intrusive_type_traits::compare key_comparator;
115 typedef typename base_class::item_counter item_counter ; ///< Item counting policy used
116 typedef typename base_class::memory_model memory_model ; ///< Memory ordering. See cds::opt::memory_model option
117 typedef typename base_class::node_allocator node_allocator_type ; ///< allocator for maintaining internal node
118 typedef typename base_class::stat stat ; ///< internal statistics type
119 typedef typename base_class::rcu_check_deadlock rcu_check_deadlock ; ///< Deadlock checking policy
120 typedef typename options::copy_policy copy_policy ; ///< key copy policy
122 typedef typename options::allocator allocator_type ; ///< Allocator for leaf nodes
123 typedef typename base_class::node_allocator node_allocator ; ///< Internal node allocator
124 typedef typename base_class::update_desc_allocator update_desc_allocator ; ///< Update descriptor allocator
126 static CDS_CONSTEXPR_CONST bool c_bExtractLockExternal = base_class::c_bExtractLockExternal; ///< Group of \p extract_xxx functions do not require external locking
130 typedef typename base_class::value_type leaf_node;
131 typedef typename base_class::internal_node internal_node;
132 typedef typename base_class::update_desc update_desc;
134 typedef typename maker::cxx_leaf_node_allocator cxx_leaf_node_allocator;
136 typedef std::unique_ptr< leaf_node, typename maker::leaf_deallocator > scoped_node_ptr;
140 typedef typename gc::scoped_lock rcu_lock ; ///< RCU scoped lock
142 /// pointer to extracted node
143 typedef cds::urcu::exempt_ptr< gc, leaf_node, value_type, typename maker::intrusive_type_traits::disposer,
144 cds::urcu::details::conventional_exempt_member_cast<leaf_node, value_type>
149 # ifndef CDS_CXX11_LAMBDA_SUPPORT
150 struct empty_insert_functor
152 void operator()( value_type& ) const
156 template <typename Q>
157 class insert_value_functor
161 insert_value_functor( Q const& v)
165 void operator()( value_type& item )
171 template <typename Func>
172 class insert_key_wrapper: protected cds::details::functor_wrapper<Func>
174 typedef cds::details::functor_wrapper<Func> base_class;
176 insert_key_wrapper( Func f ): base_class(f) {}
178 void operator()( leaf_node& item )
180 base_class::get()( item.m_Value );
184 template <typename Func>
185 class ensure_wrapper: protected cds::details::functor_wrapper<Func>
187 typedef cds::details::functor_wrapper<Func> base_class;
189 ensure_wrapper( Func f) : base_class(f) {}
191 void operator()( bool bNew, leaf_node& item, leaf_node const& )
193 base_class::get()( bNew, item.m_Value );
197 template <typename Func>
202 erase_functor( Func f )
206 void operator()( leaf_node& node )
208 cds::unref(m_func)( node.m_Value );
212 template <typename Func>
213 class find_wrapper: protected cds::details::functor_wrapper<Func>
215 typedef cds::details::functor_wrapper<Func> base_class;
217 find_wrapper( Func f )
221 template <typename Q>
222 void operator()( leaf_node& item, Q& val )
224 base_class::get()( item.m_Value, val );
231 /// Default constructor
240 /// Inserts new node with key and default value
242 The function creates a node with \p key and default value, and then inserts the node created into the map.
245 - The \ref key_type should be constructible from a value of type \p K.
246 In trivial case, \p K is equal to \ref key_type.
247 - The \ref mapped_type should be default-constructible.
249 RCU \p synchronize method can be called. RCU should not be locked.
251 Returns \p true if inserting successful, \p false otherwise.
253 template <typename K>
254 bool insert( K const& key )
256 # ifdef CDS_CXX11_LAMBDA_SUPPORT
257 return insert_key( key, [](value_type&){} );
259 return insert_key( key, empty_insert_functor() );
265 The function creates a node with copy of \p val value
266 and then inserts the node created into the map.
269 - The \ref key_type should be constructible from \p key of type \p K.
270 - The \ref value_type should be constructible from \p val of type \p V.
272 RCU \p synchronize method can be called. RCU should not be locked.
274 Returns \p true if \p val is inserted into the map, \p false otherwise.
276 template <typename K, typename V>
277 bool insert( K const& key, V const& val )
279 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key, val ));
280 if ( base_class::insert( *pNode ))
288 /// Inserts new node and initialize it by a functor
290 This function inserts new node with key \p key and if inserting is successful then it calls
291 \p func functor with signature
294 void operator()( value_type& item );
298 The argument \p item of user-defined functor \p func is the reference
299 to the map's item inserted:
300 - <tt>item.first</tt> is a const reference to item's key that cannot be changed.
301 - <tt>item.second</tt> is a reference to item's value that may be changed.
303 The user-defined functor can be passed by reference using <tt>boost::ref</tt>
304 and it is called only if inserting is successful.
306 The key_type should be constructible from value of type \p K.
308 The function allows to split creating of new item into two part:
309 - create item from \p key;
310 - insert new item into the map;
311 - if inserting is successful, initialize the value of item by calling \p func functor
313 This can be useful if complete initialization of object of \p value_type is heavyweight and
314 it is preferable that the initialization should be completed only if inserting is successful.
316 RCU \p synchronize method can be called. RCU should not be locked.
318 template <typename K, typename Func>
319 bool insert_key( const K& key, Func func )
321 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key ));
322 # ifdef CDS_CXX11_LAMBDA_SUPPORT
323 if ( base_class::insert( *pNode, [&func]( leaf_node& item ) { cds::unref(func)( item.m_Value ); } ))
325 insert_key_wrapper<Func> wrapper(func);
326 if ( base_class::insert( *pNode, cds::ref(wrapper) ))
335 # ifdef CDS_EMPLACE_SUPPORT
336 /// For key \p key inserts data of type \ref value_type constructed with <tt>std::forward<Args>(args)...</tt>
338 Returns \p true if inserting successful, \p false otherwise.
340 RCU \p synchronize method can be called. RCU should not be locked.
342 @note This function is available only for compiler that supports
343 variadic template and move semantics
345 template <typename K, typename... Args>
346 bool emplace( K&& key, Args&&... args )
348 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( std::forward<K>(key), std::forward<Args>(args)... ));
349 if ( base_class::insert( *pNode )) {
357 /// Ensures that the \p key exists in the map
359 The operation performs inserting or changing data with lock-free manner.
361 If the \p key not found in the map, then the new item created from \p key
362 is inserted into the map (note that in this case the \ref key_type should be
363 constructible from type \p K).
364 Otherwise, the functor \p func is called with item found.
365 The functor \p Func may be a function with signature:
367 void func( bool bNew, value_type& item );
372 void operator()( bool bNew, value_type& item );
377 - \p bNew - \p true if the item has been inserted, \p false otherwise
378 - \p item - item of the list
380 The functor may change any fields of the \p item.second that is \ref value_type.
382 You may pass \p func argument by reference using <tt>boost::ref</tt>.
384 RCU \p synchronize method can be called. RCU should not be locked.
386 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
387 \p second is true if new item has been added or \p false if the item with \p key
388 already is in the list.
390 template <typename K, typename Func>
391 std::pair<bool, bool> ensure( K const& key, Func func )
393 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key ));
394 # ifdef CDS_CXX11_LAMBDA_SUPPORT
395 std::pair<bool, bool> res = base_class::ensure( *pNode,
396 [&func](bool bNew, leaf_node& item, leaf_node const& ){ cds::unref(func)( bNew, item.m_Value ); }
399 ensure_wrapper<Func> wrapper( func );
400 std::pair<bool, bool> res = base_class::ensure( *pNode, cds::ref(wrapper) );
402 if ( res.first && res.second )
407 /// Delete \p key from the map
408 /**\anchor cds_nonintrusive_EllenBinTreeMap_rcu_erase_val
410 RCU \p synchronize method can be called. RCU should not be locked.
412 Return \p true if \p key is found and deleted, \p false otherwise
414 template <typename K>
415 bool erase( K const& key )
417 return base_class::erase(key);
420 /// Deletes the item from the map using \p pred predicate for searching
422 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_val "erase(K const&)"
423 but \p pred is used for key comparing.
424 \p Less functor has the interface like \p std::less.
425 \p Less must imply the same element order as the comparator used for building the map.
427 template <typename K, typename Less>
428 bool erase_with( K const& key, Less pred )
430 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
433 /// Delete \p key from the map
434 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_erase_func
436 The function searches an item with key \p key, calls \p f functor
437 and deletes the item. If \p key is not found, the functor is not called.
439 The functor \p Func interface:
442 void operator()(value_type& item) { ... }
445 The functor may be passed by reference using <tt>boost:ref</tt>
447 RCU \p synchronize method can be called. RCU should not be locked.
449 Return \p true if key is found and deleted, \p false otherwise
451 template <typename K, typename Func>
452 bool erase( K const& key, Func f )
454 # ifdef CDS_CXX11_LAMBDA_SUPPORT
455 return base_class::erase( key, [&f]( leaf_node& node) { cds::unref(f)( node.m_Value ); } );
457 erase_functor<Func> wrapper(f);
458 return base_class::erase( key, cds::ref(wrapper));
462 /// Deletes the item from the map using \p pred predicate for searching
464 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_func "erase(K const&, Func)"
465 but \p pred is used for key comparing.
466 \p Less functor has the interface like \p std::less.
467 \p Less must imply the same element order as the comparator used for building the map.
469 template <typename K, typename Less, typename Func>
470 bool erase_with( K const& key, Less pred, Func f )
472 # ifdef CDS_CXX11_LAMBDA_SUPPORT
473 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
474 [&f]( leaf_node& node) { cds::unref(f)( node.m_Value ); } );
476 erase_functor<Func> wrapper(f);
477 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(), cds::ref(wrapper));
481 /// Extracts an item with minimal key from the map
483 If the map is not empty, the function returns \p true, \p result contains a pointer to value.
484 If the map is empty, the function returns \p false, \p result is left unchanged.
486 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> minimum key.
487 It means that the function gets leftmost leaf of the tree and tries to unlink it.
488 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
489 So, the function returns the item with minimum key at the moment of tree traversing.
491 RCU \p synchronize method can be called. RCU should NOT be locked.
492 The function does not free the item.
493 The deallocator will be implicitly invoked when \p result object is destroyed or when
494 <tt>result.release()</tt> is called, see cds::urcu::exempt_ptr for explanation.
495 @note Before reusing \p result object you should call its \p release() method.
497 bool extract_min( exempt_ptr& result )
499 return base_class::extract_min_( result );
502 /// Extracts an item with maximal key from the map
504 If the map is not empty, the function returns \p true, \p result contains a pointer to extracted item.
505 If the map is empty, the function returns \p false, \p result is left unchanged.
507 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> maximal key.
508 It means that the function gets rightmost leaf of the tree and tries to unlink it.
509 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
510 So, the function returns the item with maximum key at the moment of tree traversing.
512 RCU \p synchronize method can be called. RCU should NOT be locked.
513 The function does not free the item.
514 The deallocator will be implicitly invoked when \p result object is destroyed or when
515 <tt>result.release()</tt> is called, see cds::urcu::exempt_ptr for explanation.
516 @note Before reusing \p result object you should call its \p release() method.
518 bool extract_max( exempt_ptr& result )
520 return base_class::extract_max_( result );
523 /// Extracts an item from the map
524 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_extract
525 The function searches an item with key equal to \p key in the tree,
526 unlinks it, and returns pointer to an item found in \p result parameter.
527 If \p key is not found the function returns \p false.
529 RCU \p synchronize method can be called. RCU should NOT be locked.
530 The function does not destroy the item found.
531 The dealloctor will be implicitly invoked when \p result object is destroyed or when
532 <tt>result.release()</tt> is called, see cds::urcu::exempt_ptr for explanation.
533 @note Before reusing \p result object you should call its \p release() method.
535 template <typename Q>
536 bool extract( exempt_ptr& result, Q const& key )
538 return base_class::extract_( result, key, typename base_class::node_compare());
541 /// Extracts an item from the map using \p pred for searching
543 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_extract "extract(exempt_ptr&, Q const&)"
544 but \p pred is used for key compare.
545 \p Less has the interface like \p std::less and should meet \ref cds_container_EllenBinTreeSet_rcu_less
546 "predicate requirements".
547 \p pred must imply the same element order as the comparator used for building the map.
549 template <typename Q, typename Less>
550 bool extract_with( exempt_ptr& result, Q const& val, Less pred )
552 return base_class::extract_with_( result, val,
553 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() );
556 /// Find the key \p key
557 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc
559 The function searches the item with key equal to \p key and calls the functor \p f for item found.
560 The interface of \p Func functor is:
563 void operator()( value_type& item );
566 where \p item is the item found.
568 You can pass \p f argument by reference using <tt>boost::ref</tt> or cds::ref.
570 The functor may change \p item.second.
572 The function applies RCU lock internally.
574 The function returns \p true if \p key is found, \p false otherwise.
576 template <typename K, typename Func>
577 bool find( K const& key, Func f )
579 # ifdef CDS_CXX11_LAMBDA_SUPPORT
580 return base_class::find( key, [&f](leaf_node& item, K const& ) { cds::unref(f)( item.m_Value );});
582 find_wrapper<Func> wrapper(f);
583 return base_class::find( key, cds::ref(wrapper) );
587 /// Finds the key \p val using \p pred predicate for searching
589 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc "find(K const&, Func)"
590 but \p pred is used for key comparing.
591 \p Less functor has the interface like \p std::less.
592 \p Less must imply the same element order as the comparator used for building the map.
594 template <typename K, typename Less, typename Func>
595 bool find_with( K const& key, Less pred, Func f )
597 # ifdef CDS_CXX11_LAMBDA_SUPPORT
598 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
599 [&f](leaf_node& item, K const& ) { cds::unref(f)( item.m_Value );});
601 find_wrapper<Func> wrapper(f);
602 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(), cds::ref(wrapper) );
606 /// Find the key \p key
607 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_find_val
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 The function applies RCU lock internally.
614 template <typename K>
615 bool find( K const& key )
617 return base_class::find( key );
620 /// Finds the key \p val using \p pred predicate for searching
622 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_find_val "find(K const&)"
623 but \p pred is used for key comparing.
624 \p Less functor has the interface like \p std::less.
625 \p Less must imply the same element order as the comparator used for building the map.
627 template <typename K, typename Less>
628 bool find_with( K const& key, Less pred )
630 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() );
633 /// Finds \p key and return the item found
634 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_get
635 The function searches the item with key equal to \p key and returns the pointer to item found.
636 If \p key is not found it returns \p nullptr.
638 RCU should be locked before call the function.
639 Returned pointer is valid while RCU is locked.
641 template <typename Q>
642 value_type * get( Q const& key ) const
644 leaf_node * pNode = base_class::get( key );
645 return pNode ? &pNode->m_Value : nullptr;
648 /// Finds \p key with \p pred predicate and return the item found
650 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_get "get(Q const&)"
651 but \p pred is used for comparing the keys.
653 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type
654 and \p Q in any order.
655 \p pred must imply the same element order as the comparator used for building the map.
657 template <typename Q, typename Less>
658 value_type * get_with( Q const& key, Less pred ) const
660 leaf_node * pNode = base_class::get_with( key,
661 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
662 return pNode ? &pNode->m_Value : nullptr;
671 /// Checks if the map is empty
673 Emptiness is checked by item counting: if item count is zero then the map is empty.
677 return base_class::empty();
680 /// Returns item count in the map
683 return base_class::size();
686 /// Returns const reference to internal statistics
687 stat const& statistics() const
689 return base_class::statistics();
692 /// Checks internal consistency (not atomic, not thread-safe)
694 The debugging function to check internal consistency of the tree.
696 bool check_consistency() const
698 return base_class::check_consistency();
702 }} // namespace cds::container
704 #endif //#ifndef __CDS_CONTAINER_ELLEN_BINTREE_MAP_RCU_H