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 /// For key \p key inserts data of type \ref value_type constructed with <tt>std::forward<Args>(args)...</tt>
337 Returns \p true if inserting successful, \p false otherwise.
339 RCU \p synchronize method can be called. RCU should not be locked.
341 template <typename K, typename... Args>
342 bool emplace( K&& key, Args&&... args )
344 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( std::forward<K>(key), std::forward<Args>(args)... ));
345 if ( base_class::insert( *pNode )) {
352 /// Ensures that the \p key exists in the map
354 The operation performs inserting or changing data with lock-free manner.
356 If the \p key not found in the map, then the new item created from \p key
357 is inserted into the map (note that in this case the \ref key_type should be
358 constructible from type \p K).
359 Otherwise, the functor \p func is called with item found.
360 The functor \p Func may be a function with signature:
362 void func( bool bNew, value_type& item );
367 void operator()( bool bNew, value_type& item );
372 - \p bNew - \p true if the item has been inserted, \p false otherwise
373 - \p item - item of the list
375 The functor may change any fields of the \p item.second that is \ref value_type.
377 You may pass \p func argument by reference using <tt>boost::ref</tt>.
379 RCU \p synchronize method can be called. RCU should not be locked.
381 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
382 \p second is true if new item has been added or \p false if the item with \p key
383 already is in the list.
385 template <typename K, typename Func>
386 std::pair<bool, bool> ensure( K const& key, Func func )
388 scoped_node_ptr pNode( cxx_leaf_node_allocator().New( key ));
389 # ifdef CDS_CXX11_LAMBDA_SUPPORT
390 std::pair<bool, bool> res = base_class::ensure( *pNode,
391 [&func](bool bNew, leaf_node& item, leaf_node const& ){ cds::unref(func)( bNew, item.m_Value ); }
394 ensure_wrapper<Func> wrapper( func );
395 std::pair<bool, bool> res = base_class::ensure( *pNode, cds::ref(wrapper) );
397 if ( res.first && res.second )
402 /// Delete \p key from the map
403 /**\anchor cds_nonintrusive_EllenBinTreeMap_rcu_erase_val
405 RCU \p synchronize method can be called. RCU should not be locked.
407 Return \p true if \p key is found and deleted, \p false otherwise
409 template <typename K>
410 bool erase( K const& key )
412 return base_class::erase(key);
415 /// Deletes the item from the map using \p pred predicate for searching
417 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_val "erase(K const&)"
418 but \p pred is used for key comparing.
419 \p Less functor has the interface like \p std::less.
420 \p Less must imply the same element order as the comparator used for building the map.
422 template <typename K, typename Less>
423 bool erase_with( K const& key, Less pred )
425 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
428 /// Delete \p key from the map
429 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_erase_func
431 The function searches an item with key \p key, calls \p f functor
432 and deletes the item. If \p key is not found, the functor is not called.
434 The functor \p Func interface:
437 void operator()(value_type& item) { ... }
440 The functor may be passed by reference using <tt>boost:ref</tt>
442 RCU \p synchronize method can be called. RCU should not be locked.
444 Return \p true if key is found and deleted, \p false otherwise
446 template <typename K, typename Func>
447 bool erase( K const& key, Func f )
449 # ifdef CDS_CXX11_LAMBDA_SUPPORT
450 return base_class::erase( key, [&f]( leaf_node& node) { cds::unref(f)( node.m_Value ); } );
452 erase_functor<Func> wrapper(f);
453 return base_class::erase( key, cds::ref(wrapper));
457 /// Deletes the item from the map using \p pred predicate for searching
459 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_erase_func "erase(K const&, Func)"
460 but \p pred is used for key comparing.
461 \p Less functor has the interface like \p std::less.
462 \p Less must imply the same element order as the comparator used for building the map.
464 template <typename K, typename Less, typename Func>
465 bool erase_with( K const& key, Less pred, Func f )
467 # ifdef CDS_CXX11_LAMBDA_SUPPORT
468 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
469 [&f]( leaf_node& node) { cds::unref(f)( node.m_Value ); } );
471 erase_functor<Func> wrapper(f);
472 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(), cds::ref(wrapper));
476 /// Extracts an item with minimal key from the map
478 If the map is not empty, the function returns \p true, \p result contains a pointer to value.
479 If the map is empty, the function returns \p false, \p result is left unchanged.
481 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> minimum key.
482 It means that the function gets leftmost leaf of the tree and tries to unlink it.
483 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
484 So, the function returns the item with minimum key at the moment of tree traversing.
486 RCU \p synchronize method can be called. RCU should NOT be locked.
487 The function does not free the item.
488 The deallocator will be implicitly invoked when \p result object is destroyed or when
489 <tt>result.release()</tt> is called, see cds::urcu::exempt_ptr for explanation.
490 @note Before reusing \p result object you should call its \p release() method.
492 bool extract_min( exempt_ptr& result )
494 return base_class::extract_min_( result );
497 /// Extracts an item with maximal key from the map
499 If the map is not empty, the function returns \p true, \p result contains a pointer to extracted item.
500 If the map is empty, the function returns \p false, \p result is left unchanged.
502 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> maximal key.
503 It means that the function gets rightmost leaf of the tree and tries to unlink it.
504 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
505 So, the function returns the item with maximum key at the moment of tree traversing.
507 RCU \p synchronize method can be called. RCU should NOT be locked.
508 The function does not free the item.
509 The deallocator will be implicitly invoked when \p result object is destroyed or when
510 <tt>result.release()</tt> is called, see cds::urcu::exempt_ptr for explanation.
511 @note Before reusing \p result object you should call its \p release() method.
513 bool extract_max( exempt_ptr& result )
515 return base_class::extract_max_( result );
518 /// Extracts an item from the map
519 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_extract
520 The function searches an item with key equal to \p key in the tree,
521 unlinks it, and returns pointer to an item found in \p result parameter.
522 If \p key is not found the function returns \p false.
524 RCU \p synchronize method can be called. RCU should NOT be locked.
525 The function does not destroy the item found.
526 The dealloctor will be implicitly invoked when \p result object is destroyed or when
527 <tt>result.release()</tt> is called, see cds::urcu::exempt_ptr for explanation.
528 @note Before reusing \p result object you should call its \p release() method.
530 template <typename Q>
531 bool extract( exempt_ptr& result, Q const& key )
533 return base_class::extract_( result, key, typename base_class::node_compare());
536 /// Extracts an item from the map using \p pred for searching
538 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_extract "extract(exempt_ptr&, Q const&)"
539 but \p pred is used for key compare.
540 \p Less has the interface like \p std::less and should meet \ref cds_container_EllenBinTreeSet_rcu_less
541 "predicate requirements".
542 \p pred must imply the same element order as the comparator used for building the map.
544 template <typename Q, typename Less>
545 bool extract_with( exempt_ptr& result, Q const& val, Less pred )
547 return base_class::extract_with_( result, val,
548 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() );
551 /// Find the key \p key
552 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc
554 The function searches the item with key equal to \p key and calls the functor \p f for item found.
555 The interface of \p Func functor is:
558 void operator()( value_type& item );
561 where \p item is the item found.
563 You can pass \p f argument by reference using <tt>boost::ref</tt> or cds::ref.
565 The functor may change \p item.second.
567 The function applies RCU lock internally.
569 The function returns \p true if \p key is found, \p false otherwise.
571 template <typename K, typename Func>
572 bool find( K const& key, Func f )
574 # ifdef CDS_CXX11_LAMBDA_SUPPORT
575 return base_class::find( key, [&f](leaf_node& item, K const& ) { cds::unref(f)( item.m_Value );});
577 find_wrapper<Func> wrapper(f);
578 return base_class::find( key, cds::ref(wrapper) );
582 /// Finds the key \p val using \p pred predicate for searching
584 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_find_cfunc "find(K const&, Func)"
585 but \p pred is used for key comparing.
586 \p Less functor has the interface like \p std::less.
587 \p Less must imply the same element order as the comparator used for building the map.
589 template <typename K, typename Less, typename Func>
590 bool find_with( K const& key, Less pred, Func f )
592 # ifdef CDS_CXX11_LAMBDA_SUPPORT
593 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(),
594 [&f](leaf_node& item, K const& ) { cds::unref(f)( item.m_Value );});
596 find_wrapper<Func> wrapper(f);
597 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >(), cds::ref(wrapper) );
601 /// Find the key \p key
602 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_find_val
604 The function searches the item with key equal to \p key
605 and returns \p true if it is found, and \p false otherwise.
607 The function applies RCU lock internally.
609 template <typename K>
610 bool find( K const& key )
612 return base_class::find( key );
615 /// Finds the key \p val using \p pred predicate for searching
617 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_find_val "find(K const&)"
618 but \p pred is used for key comparing.
619 \p Less functor has the interface like \p std::less.
620 \p Less must imply the same element order as the comparator used for building the map.
622 template <typename K, typename Less>
623 bool find_with( K const& key, Less pred )
625 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >() );
628 /// Finds \p key and return the item found
629 /** \anchor cds_nonintrusive_EllenBinTreeMap_rcu_get
630 The function searches the item with key equal to \p key and returns the pointer to item found.
631 If \p key is not found it returns \p nullptr.
633 RCU should be locked before call the function.
634 Returned pointer is valid while RCU is locked.
636 template <typename Q>
637 value_type * get( Q const& key ) const
639 leaf_node * pNode = base_class::get( key );
640 return pNode ? &pNode->m_Value : nullptr;
643 /// Finds \p key with \p pred predicate and return the item found
645 The function is an analog of \ref cds_nonintrusive_EllenBinTreeMap_rcu_get "get(Q const&)"
646 but \p pred is used for comparing the keys.
648 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type
649 and \p Q in any order.
650 \p pred must imply the same element order as the comparator used for building the map.
652 template <typename Q, typename Less>
653 value_type * get_with( Q const& key, Less pred ) const
655 leaf_node * pNode = base_class::get_with( key,
656 cds::details::predicate_wrapper< leaf_node, Less, typename maker::key_accessor >());
657 return pNode ? &pNode->m_Value : nullptr;
666 /// Checks if the map is empty
668 Emptiness is checked by item counting: if item count is zero then the map is empty.
672 return base_class::empty();
675 /// Returns item count in the map
678 return base_class::size();
681 /// Returns const reference to internal statistics
682 stat const& statistics() const
684 return base_class::statistics();
687 /// Checks internal consistency (not atomic, not thread-safe)
689 The debugging function to check internal consistency of the tree.
691 bool check_consistency() const
693 return base_class::check_consistency();
697 }} // namespace cds::container
699 #endif //#ifndef __CDS_CONTAINER_ELLEN_BINTREE_MAP_RCU_H