3 #ifndef CDSLIB_CONTAINER_ELLEN_BINTREE_SET_RCU_H
4 #define CDSLIB_CONTAINER_ELLEN_BINTREE_SET_RCU_H
6 #include <cds/container/details/ellen_bintree_base.h>
7 #include <cds/intrusive/ellen_bintree_rcu.h>
9 namespace cds { namespace container {
11 /// Set based on Ellen's et al binary search tree (RCU specialization)
12 /** @ingroup cds_nonintrusive_set
13 @ingroup cds_nonintrusive_tree
14 @anchor cds_container_EllenBinTreeSet_rcu
17 - [2010] F.Ellen, P.Fatourou, E.Ruppert, F.van Breugel "Non-blocking Binary Search Tree"
19 %EllenBinTreeSet is an unbalanced leaf-oriented binary search tree that implements the <i>set</i>
20 abstract data type. Nodes maintains child pointers but not parent pointers.
21 Every internal node has exactly two children, and all data of type \p T currently in
22 the tree are stored in the leaves. Internal nodes of the tree are used to direct \p find
23 operation along the path to the correct leaf. The keys (of \p Key type) stored in internal nodes
24 may or may not be in the set. \p Key type is a subset of \p T type.
25 There should be exactly defined a key extracting functor for converting object of type \p T to
26 object of type \p Key.
28 Due to \p extract_min and \p extract_max member functions the \p %EllenBinTreeSet can act as
29 a <i>priority queue</i>. In this case you should provide unique compound key, for example,
30 the priority value plus some uniformly distributed random value.
32 @warning Recall the tree is <b>unbalanced</b>. The complexity of operations is <tt>O(log N)</tt>
33 for uniformly distributed random keys, but in worst case the complexity is <tt>O(N)</tt>.
35 @note In the current implementation we do not use helping technique described in original paper.
36 So, the current implementation is near to fine-grained lock-based tree.
37 Helping will be implemented in future release
39 <b>Template arguments</b> :
40 - \p RCU - one of \ref cds_urcu_gc "RCU type"
41 - \p Key - key type, a subset of \p T
42 - \p T - type to be stored in tree's leaf nodes.
43 - \p Traits - set traits, default is \p ellen_bintree::traits.
44 It is possible to declare option-based tree with \p ellen_bintree::make_set_traits metafunction
45 instead of \p Traits template argument.
47 @note Before including <tt><cds/container/ellen_bintree_set_rcu.h></tt> you should include appropriate RCU header file,
48 see \ref cds_urcu_gc "RCU type" for list of existing RCU class and corresponding header files.
50 @anchor cds_container_EllenBinTreeSet_rcu_less
51 <b>Predicate requirements</b>
53 opt::less, opt::compare and other predicates using with member fuctions should accept at least parameters
54 of type \p T and \p Key in any combination.
55 For example, for \p Foo struct with \p std::string key field the appropiate \p less functor is:
64 bool operator()( Foo const& v1, Foo const& v2 ) const
65 { return v1.m_strKey < v2.m_strKey ; }
67 bool operator()( Foo const& v, std::string const& s ) const
68 { return v.m_strKey < s ; }
70 bool operator()( std::string const& s, Foo const& v ) const
71 { return s < v.m_strKey ; }
73 // Support comparing std::string and char const *
74 bool operator()( std::string const& s, char const * p ) const
75 { return s.compare(p) < 0 ; }
77 bool operator()( Foo const& v, char const * p ) const
78 { return v.m_strKey.compare(p) < 0 ; }
80 bool operator()( char const * p, std::string const& s ) const
81 { return s.compare(p) > 0; }
83 bool operator()( char const * p, Foo const& v ) const
84 { return v.m_strKey.compare(p) > 0; }
93 #ifdef CDS_DOXYGEN_INVOKED
94 class Traits = ellen_bintree::traits
99 class EllenBinTreeSet< cds::urcu::gc<RCU>, Key, T, Traits >
100 #ifdef CDS_DOXYGEN_INVOKED
101 : public cds::intrusive::EllenBinTree< cds::urcu::gc<RCU>, Key, T, Traits >
103 : public ellen_bintree::details::make_ellen_bintree_set< cds::urcu::gc<RCU>, Key, T, Traits >::type
107 typedef ellen_bintree::details::make_ellen_bintree_set< cds::urcu::gc<RCU>, Key, T, Traits > maker;
108 typedef typename maker::type base_class;
112 typedef cds::urcu::gc<RCU> gc; ///< RCU Garbage collector
113 typedef Key key_type; ///< type of a key stored in internal nodes; key is a part of \p value_type
114 typedef T value_type; ///< type of value stored in the binary tree
115 typedef Traits traits; ///< Traits template parameter
117 # ifdef CDS_DOXYGEN_INVOKED
118 typedef implementation_defined key_comparator; ///< key compare functor based on \p Traits::compare and \p Traits::less
120 typedef typename maker::intrusive_traits::compare key_comparator;
122 typedef typename base_class::item_counter item_counter; ///< Item counting policy
123 typedef typename base_class::memory_model memory_model; ///< Memory ordering, see \p cds::opt::memory_model
124 typedef typename base_class::stat stat; ///< internal statistics type
125 typedef typename base_class::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
126 typedef typename traits::key_extractor key_extractor; ///< key extracting functor
127 typedef typename traits::back_off back_off; ///< Back-off strategy
130 typedef typename traits::allocator allocator_type; ///< Allocator for leaf nodes
131 typedef typename base_class::node_allocator node_allocator; ///< Internal node allocator
132 typedef typename base_class::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
134 static CDS_CONSTEXPR const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal; ///< Group of \p extract_xxx functions do not require external locking
137 typedef cds::container::ellen_bintree::implementation_tag implementation_tag;
142 typedef typename maker::cxx_leaf_node_allocator cxx_leaf_node_allocator;
143 typedef typename base_class::value_type leaf_node;
144 typedef typename base_class::internal_node internal_node;
145 typedef std::unique_ptr< leaf_node, typename maker::intrusive_traits::disposer > scoped_node_ptr;
149 typedef typename gc::scoped_lock rcu_lock; ///< RCU scoped lock
151 /// pointer to extracted node
152 using exempt_ptr = cds::urcu::exempt_ptr < gc, leaf_node, value_type, typename maker::intrusive_traits::disposer,
153 cds::urcu::details::conventional_exempt_member_cast < leaf_node, value_type >
157 /// Default constructor
168 The function creates a node with copy of \p val value
169 and then inserts the node created into the set.
171 The type \p Q should contain at least the complete key for the node.
172 The object of \ref value_type should be constructible from a value of type \p Q.
173 In trivial case, \p Q is equal to \ref value_type.
175 RCU \p synchronize() method can be called. RCU should not be locked.
177 Returns \p true if \p val is inserted into the set, \p false otherwise.
179 template <typename Q>
180 bool insert( Q const& val )
182 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
183 if ( base_class::insert( *sp.get() )) {
192 The function allows to split creating of new item into two part:
193 - create item with key only
194 - insert new item into the set
195 - if inserting is success, calls \p f functor to initialize value-fields of \p val.
197 The functor signature is:
199 void func( value_type& val );
201 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
202 \p val no any other changes could be made on this set's item by concurrent threads.
203 The user-defined functor is called only if the inserting is success.
205 RCU \p synchronize() can be called. RCU should not be locked.
207 template <typename Q, typename Func>
208 bool insert( Q const& val, Func f )
210 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
211 if ( base_class::insert( *sp.get(), [&f]( leaf_node& val ) { f( val.m_Value ); } )) {
220 The operation performs inserting or changing data with lock-free manner.
222 If the item \p val is not found in the set, then \p val is inserted into the set
223 iff \p bAllowInsert is \p true.
224 Otherwise, the functor \p func is called with item found.
225 The functor \p func signature is:
227 void func( bool bNew, value_type& item, value_type& val );
230 - \p bNew - \p true if the item has been inserted, \p false otherwise
231 - \p item - item of the set
232 - \p val - argument \p val passed into the \p %update() function
234 The functor can change non-key fields of the \p item; however, \p func must guarantee
235 that during changing no any other modifications could be made on this item by concurrent threads.
237 RCU \p synchronize method can be called. RCU should not be locked.
239 Returns std::pair<bool, bool> where \p first is \p true if operation is successfull,
240 i.e. the node has been inserted or updated,
241 \p second is \p true if new item has been added or \p false if the item with \p key
244 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
246 template <typename Q, typename Func>
247 std::pair<bool, bool> update( Q const& val, Func func, bool bAllowInsert = true )
249 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
250 std::pair<bool, bool> bRes = base_class::update( *sp,
251 [&func, &val](bool bNew, leaf_node& node, leaf_node&){ func( bNew, node.m_Value, val ); },
253 if ( bRes.first && bRes.second )
258 // Deprecated, use update()
259 template <typename Q, typename Func>
260 std::pair<bool, bool> ensure( const Q& val, Func func )
262 return update( val, func true );
266 /// Inserts data of type \p value_type created in-place from \p args
268 Returns \p true if inserting successful, \p false otherwise.
270 RCU \p synchronize method can be called. RCU should not be locked.
272 template <typename... Args>
273 bool emplace( Args&&... args )
275 scoped_node_ptr sp( cxx_leaf_node_allocator().New( std::forward<Args>(args)... ));
276 if ( base_class::insert( *sp.get() )) {
283 /// Delete \p key from the set
284 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_erase_val
286 The item comparator should be able to compare the type \p value_type
289 RCU \p synchronize method can be called. RCU should not be locked.
291 Return \p true if key is found and deleted, \p false otherwise
293 template <typename Q>
294 bool erase( Q const& key )
296 return base_class::erase( key );
299 /// Deletes the item from the set using \p pred predicate for searching
301 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_erase_val "erase(Q const&)"
302 but \p pred is used for key comparing.
303 \p Less functor has the interface like \p std::less.
304 \p Less must imply the same element order as the comparator used for building the set.
306 template <typename Q, typename Less>
307 bool erase_with( Q const& key, Less pred )
310 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
313 /// Delete \p key from the set
314 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_erase_func
316 The function searches an item with key \p key, calls \p f functor
317 and deletes the item. If \p key is not found, the functor is not called.
319 The functor \p Func interface:
322 void operator()(value_type const& val);
326 Since the key of MichaelHashSet's \p value_type is not explicitly specified,
327 template parameter \p Q defines the key type searching in the list.
328 The list item comparator should be able to compare the type \p T of list item
331 RCU \p synchronize method can be called. RCU should not be locked.
333 Return \p true if key is found and deleted, \p false otherwise
337 template <typename Q, typename Func>
338 bool erase( Q const& key, Func f )
340 return base_class::erase( key, [&f]( leaf_node const& node) { f( node.m_Value ); } );
343 /// Deletes the item from the set using \p pred predicate for searching
345 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_erase_func "erase(Q const&, Func)"
346 but \p pred is used for key comparing.
347 \p Less functor has the interface like \p std::less.
348 \p Less must imply the same element order as the comparator used for building the set.
350 template <typename Q, typename Less, typename Func>
351 bool erase_with( Q const& key, Less pred, Func f )
354 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
355 [&f]( leaf_node const& node) { f( node.m_Value ); } );
358 /// Extracts an item with minimal key from the set
360 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the leftmost item.
361 If the set is empty, returns empty \p exempt_ptr.
363 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> minimum key.
364 It means that the function gets leftmost leaf of the tree and tries to unlink it.
365 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
366 So, the function returns the item with minimum key at the moment of tree traversing.
368 RCU \p synchronize method can be called. RCU should NOT be locked.
369 The function does not free the item.
370 The deallocator will be implicitly invoked when the returned object is destroyed or when
371 its \p release() member function is called.
373 exempt_ptr extract_min()
375 return exempt_ptr( base_class::extract_min_());
378 /// Extracts an item with maximal key from the set
380 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the rightmost item.
381 If the set is empty, returns empty \p exempt_ptr.
383 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> maximal key.
384 It means that the function gets rightmost leaf of the tree and tries to unlink it.
385 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
386 So, the function returns the item with maximum key at the moment of tree traversing.
388 RCU \p synchronize method can be called. RCU should NOT be locked.
389 The function does not free the item.
390 The deallocator will be implicitly invoked when the returned object is destroyed or when
391 its \p release() member function is called.
393 exempt_ptr extract_max()
395 return exempt_ptr( base_class::extract_max_());
398 /// Extracts an item from the set
399 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_extract
400 The function searches an item with key equal to \p key in the tree,
401 unlinks it, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to an item found.
402 If \p key is not found the function returns an empty \p exempt_ptr.
404 RCU \p synchronize method can be called. RCU should NOT be locked.
405 The function does not destroy the item found.
406 The dealloctor will be implicitly invoked when the returned object is destroyed or when
407 its release() member function is called.
409 template <typename Q>
410 exempt_ptr extract( Q const& key )
412 return exempt_ptr( base_class::extract_( key, typename base_class::node_compare()));
415 /// Extracts an item from the set using \p pred for searching
417 The function is an analog of \p extract(Q const&) but \p pred is used for key compare.
418 \p Less has the interface like \p std::less and should meet \ref cds_container_EllenBinTreeSet_rcu_less
419 "predicate requirements".
420 \p pred must imply the same element order as the comparator used for building the set.
422 template <typename Q, typename Less>
423 exempt_ptr extract_with( Q const& key, Less pred )
426 return exempt_ptr( base_class::extract_with_( key,
427 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >() ));
430 /// Find the key \p key
432 @anchor cds_nonintrusive_EllenBinTreeSet_rcu_find_func
434 The function searches the item with key equal to \p key and calls the functor \p f for item found.
435 The interface of \p Func functor is:
438 void operator()( value_type& item, Q& key );
441 where \p item is the item found, \p key is the <tt>find</tt> function argument.
443 The functor may change non-key fields of \p item. Note that the functor is only guarantee
444 that \p item cannot be disposed during functor is executing.
445 The functor does not serialize simultaneous access to the set's \p item. If such access is
446 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
448 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
449 can modify both arguments.
451 Note the hash functor specified for class \p Traits template parameter
452 should accept a parameter of type \p Q that may be not the same as \p value_type.
454 The function applies RCU lock internally.
456 The function returns \p true if \p key is found, \p false otherwise.
458 template <typename Q, typename Func>
459 bool find( Q& key, Func f ) const
461 return base_class::find( key, [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); });
464 template <typename Q, typename Func>
465 bool find( Q const& key, Func f ) const
467 return base_class::find( key, [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
471 /// Finds the key \p key using \p pred predicate for searching
473 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_find_func "find(Q&, Func)"
474 but \p pred is used for key comparing.
475 \p Less functor has the interface like \p std::less.
476 \p Less must imply the same element order as the comparator used for building the set.
478 template <typename Q, typename Less, typename Func>
479 bool find_with( Q& key, Less pred, Func f ) const
482 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
483 [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); } );
486 template <typename Q, typename Less, typename Func>
487 bool find_with( Q const& key, Less pred, Func f ) const
490 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
491 [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
495 /// Checks whether the set contains \p key
497 The function searches the item with key equal to \p key
498 and returns \p true if it is found, and \p false otherwise.
500 The function applies RCU lock internally.
502 template <typename Q>
503 bool contains( Q const& key ) const
505 return base_class::contains( key );
508 // Deprecated, use contains()
509 template <typename Q>
510 bool find( Q const& key ) const
512 return contains( key );
516 /// Checks whether the set contains \p key using \p pred predicate for searching
518 The function is similar to <tt>contains( key )</tt> but \p pred is used for key comparing.
519 \p Less functor has the interface like \p std::less and should meet \ref cds_intrusive_EllenBinTree_rcu_less
520 "Predicate requirements".
521 \p Less must imply the same element order as the comparator used for building the set.
522 \p pred should accept arguments of type \p Q, \p key_type, \p value_type in any combination.
524 template <typename Q, typename Less>
525 bool contains( Q const& key, Less pred ) const
528 return base_class::contains( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
531 // DEprecated, use contains()
532 template <typename Q, typename Less>
533 bool find_with( Q const& key, Less pred ) const
535 return contains( key, pred );
539 /// Finds \p key and return the item found
540 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_get
541 The function searches the item with key equal to \p key and returns the pointer to item found.
542 If \p key is not found it returns \p nullptr.
544 RCU should be locked before call the function.
545 Returned pointer is valid while RCU is locked.
547 template <typename Q>
548 value_type * get( Q const& key ) const
550 leaf_node * pNode = base_class::get( key );
551 return pNode ? &pNode->m_Value : nullptr;
554 /// Finds \p key with \p pred predicate and return the item found
556 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_get "get(Q const&)"
557 but \p pred is used for comparing the keys.
559 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type
560 and \p Q in any order.
561 \p pred must imply the same element order as the comparator used for building the set.
563 template <typename Q, typename Less>
564 value_type * get_with( Q const& key, Less pred ) const
567 leaf_node * pNode = base_class::get_with( key,
568 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
569 return pNode ? &pNode->m_Value : nullptr;
572 /// Clears the set (non-atomic)
574 The function unlink all items from the tree.
575 The function is not atomic, thus, in multi-threaded environment with parallel insertions
579 assert( set.empty() );
581 the assertion could be raised.
583 For each leaf the \ref disposer will be called after unlinking.
585 RCU \p synchronize method can be called. RCU should not be locked.
592 /// Checks if the set is empty
595 return base_class::empty();
598 /// Returns item count in the set
600 Only leaf nodes containing user data are counted.
602 The value returned depends on item counter type provided by \p Traits template parameter.
603 If it is \p atomicity::empty_item_counter \p %size() always returns 0.
604 Therefore, the function is not suitable for checking the tree emptiness, use \p empty()
605 member function for this purpose.
609 return base_class::size();
612 /// Returns const reference to internal statistics
613 stat const& statistics() const
615 return base_class::statistics();
618 /// Checks internal consistency (not atomic, not thread-safe)
620 The debugging function to check internal consistency of the tree.
622 bool check_consistency() const
624 return base_class::check_consistency();
627 }} // namespace cds::container
629 #endif // #ifndef CDSLIB_CONTAINER_ELLEN_BINTREE_SET_RCU_H