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 ); } )) {
218 /// Ensures that the item exists in the set
220 The operation performs inserting or changing data with lock-free manner.
222 If the \p val key not found in the set, then the new item created from \p val
223 is inserted into the set. Otherwise, the functor \p func is called with the item found.
224 The functor \p Func should be a function with signature:
226 void func( bool bNew, value_type& item, const Q& val );
231 void operator()( bool bNew, value_type& item, const Q& val );
236 - \p bNew - \p true if the item has been inserted, \p false otherwise
237 - \p item - item of the set
238 - \p val - argument \p key passed into the \p ensure function
240 The functor may change non-key fields of the \p item; however, \p func must guarantee
241 that during changing no any other modifications could be made on this item by concurrent threads.
243 RCU \p synchronize() can be called. RCU should not be locked.
245 Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
246 \p second is true if new item has been added or \p false if the item with \p key
247 already is in the set.
249 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
251 template <typename Q, typename Func>
252 std::pair<bool, bool> ensure( const Q& val, Func func )
254 scoped_node_ptr sp( cxx_leaf_node_allocator().New( val ));
255 std::pair<bool, bool> bRes = base_class::ensure( *sp,
256 [&func, &val](bool bNew, leaf_node& node, leaf_node&){ func( bNew, node.m_Value, val ); });
257 if ( bRes.first && bRes.second )
262 /// Inserts data of type \p value_type created in-place from \p args
264 Returns \p true if inserting successful, \p false otherwise.
266 RCU \p synchronize method can be called. RCU should not be locked.
268 template <typename... Args>
269 bool emplace( Args&&... args )
271 scoped_node_ptr sp( cxx_leaf_node_allocator().New( std::forward<Args>(args)... ));
272 if ( base_class::insert( *sp.get() )) {
279 /// Delete \p key from the set
280 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_erase_val
282 The item comparator should be able to compare the type \p value_type
285 RCU \p synchronize method can be called. RCU should not be locked.
287 Return \p true if key is found and deleted, \p false otherwise
289 template <typename Q>
290 bool erase( Q const& key )
292 return base_class::erase( key );
295 /// Deletes the item from the set using \p pred predicate for searching
297 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_erase_val "erase(Q const&)"
298 but \p pred is used for key comparing.
299 \p Less functor has the interface like \p std::less.
300 \p Less must imply the same element order as the comparator used for building the set.
302 template <typename Q, typename Less>
303 bool erase_with( Q const& key, Less pred )
306 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
309 /// Delete \p key from the set
310 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_erase_func
312 The function searches an item with key \p key, calls \p f functor
313 and deletes the item. If \p key is not found, the functor is not called.
315 The functor \p Func interface:
318 void operator()(value_type const& val);
322 Since the key of MichaelHashSet's \p value_type is not explicitly specified,
323 template parameter \p Q defines the key type searching in the list.
324 The list item comparator should be able to compare the type \p T of list item
327 RCU \p synchronize method can be called. RCU should not be locked.
329 Return \p true if key is found and deleted, \p false otherwise
333 template <typename Q, typename Func>
334 bool erase( Q const& key, Func f )
336 return base_class::erase( key, [&f]( leaf_node const& node) { f( node.m_Value ); } );
339 /// Deletes the item from the set using \p pred predicate for searching
341 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_erase_func "erase(Q const&, Func)"
342 but \p pred is used for key comparing.
343 \p Less functor has the interface like \p std::less.
344 \p Less must imply the same element order as the comparator used for building the set.
346 template <typename Q, typename Less, typename Func>
347 bool erase_with( Q const& key, Less pred, Func f )
350 return base_class::erase_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
351 [&f]( leaf_node const& node) { f( node.m_Value ); } );
354 /// Extracts an item with minimal key from the set
356 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the leftmost item.
357 If the set is empty, returns empty \p exempt_ptr.
359 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> minimum key.
360 It means that the function gets leftmost leaf of the tree and tries to unlink it.
361 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
362 So, the function returns the item with minimum key at the moment of tree traversing.
364 RCU \p synchronize method can be called. RCU should NOT be locked.
365 The function does not free the item.
366 The deallocator will be implicitly invoked when the returned object is destroyed or when
367 its \p release() member function is called.
369 exempt_ptr extract_min()
371 return exempt_ptr( base_class::extract_min_());
374 /// Extracts an item with maximal key from the set
376 Returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the rightmost item.
377 If the set is empty, returns empty \p exempt_ptr.
379 @note Due the concurrent nature of the set, the function extracts <i>nearly</i> maximal key.
380 It means that the function gets rightmost leaf of the tree and tries to unlink it.
381 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
382 So, the function returns the item with maximum key at the moment of tree traversing.
384 RCU \p synchronize method can be called. RCU should NOT be locked.
385 The function does not free the item.
386 The deallocator will be implicitly invoked when the returned object is destroyed or when
387 its \p release() member function is called.
389 exempt_ptr extract_max()
391 return exempt_ptr( base_class::extract_max_());
394 /// Extracts an item from the set
395 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_extract
396 The function searches an item with key equal to \p key in the tree,
397 unlinks it, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to an item found.
398 If \p key is not found the function returns an empty \p exempt_ptr.
400 RCU \p synchronize method can be called. RCU should NOT be locked.
401 The function does not destroy the item found.
402 The dealloctor will be implicitly invoked when the returned object is destroyed or when
403 its release() member function is called.
405 template <typename Q>
406 exempt_ptr extract( Q const& key )
408 return exempt_ptr( base_class::extract_( key, typename base_class::node_compare()));
411 /// Extracts an item from the set using \p pred for searching
413 The function is an analog of \p extract(Q const&) but \p pred is used for key compare.
414 \p Less has the interface like \p std::less and should meet \ref cds_container_EllenBinTreeSet_rcu_less
415 "predicate requirements".
416 \p pred must imply the same element order as the comparator used for building the set.
418 template <typename Q, typename Less>
419 exempt_ptr extract_with( Q const& key, Less pred )
422 return exempt_ptr( base_class::extract_with_( key,
423 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >() ));
426 /// Find the key \p key
428 @anchor cds_nonintrusive_EllenBinTreeSet_rcu_find_func
430 The function searches the item with key equal to \p key and calls the functor \p f for item found.
431 The interface of \p Func functor is:
434 void operator()( value_type& item, Q& key );
437 where \p item is the item found, \p key is the <tt>find</tt> function argument.
439 The functor may change non-key fields of \p item. Note that the functor is only guarantee
440 that \p item cannot be disposed during functor is executing.
441 The functor does not serialize simultaneous access to the set's \p item. If such access is
442 possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.
444 The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
445 can modify both arguments.
447 Note the hash functor specified for class \p Traits template parameter
448 should accept a parameter of type \p Q that may be not the same as \p value_type.
450 The function applies RCU lock internally.
452 The function returns \p true if \p key is found, \p false otherwise.
454 template <typename Q, typename Func>
455 bool find( Q& key, Func f ) const
457 return base_class::find( key, [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); });
460 template <typename Q, typename Func>
461 bool find( Q const& key, Func f ) const
463 return base_class::find( key, [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
467 /// Finds the key \p key using \p pred predicate for searching
469 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_find_func "find(Q&, Func)"
470 but \p pred is used for key comparing.
471 \p Less functor has the interface like \p std::less.
472 \p Less must imply the same element order as the comparator used for building the set.
474 template <typename Q, typename Less, typename Func>
475 bool find_with( Q& key, Less pred, Func f ) const
478 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
479 [&f]( leaf_node& node, Q& v ) { f( node.m_Value, v ); } );
482 template <typename Q, typename Less, typename Func>
483 bool find_with( Q const& key, Less pred, Func f ) const
486 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >(),
487 [&f]( leaf_node& node, Q const& v ) { f( node.m_Value, v ); } );
491 /// Find the key \p key
492 /** @anchor cds_nonintrusive_EllenBinTreeSet_rcu_find_val
494 The function searches the item with key equal to \p key
495 and returns \p true if it is found, and \p false otherwise.
497 Note the hash functor specified for class \p Traits template parameter
498 should accept a parameter of type \p Q that may be not the same as \ref value_type.
500 The function applies RCU lock internally.
502 template <typename Q>
503 bool find( Q const& key ) const
505 return base_class::find( key );
508 /// Finds the key \p key using \p pred predicate for searching
510 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_find_val "find(Q const&)"
511 but \p pred is used for key comparing.
512 \p Less functor has the interface like \p std::less.
513 \p Less must imply the same element order as the comparator used for building the set.
515 template <typename Q, typename Less>
516 bool find_with( Q const& key, Less pred ) const
519 return base_class::find_with( key, cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
522 /// Finds \p key and return the item found
523 /** \anchor cds_nonintrusive_EllenBinTreeSet_rcu_get
524 The function searches the item with key equal to \p key and returns the pointer to item found.
525 If \p key is not found it returns \p nullptr.
527 RCU should be locked before call the function.
528 Returned pointer is valid while RCU is locked.
530 template <typename Q>
531 value_type * get( Q const& key ) const
533 leaf_node * pNode = base_class::get( key );
534 return pNode ? &pNode->m_Value : nullptr;
537 /// Finds \p key with \p pred predicate and return the item found
539 The function is an analog of \ref cds_nonintrusive_EllenBinTreeSet_rcu_get "get(Q const&)"
540 but \p pred is used for comparing the keys.
542 \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type
543 and \p Q in any order.
544 \p pred must imply the same element order as the comparator used for building the set.
546 template <typename Q, typename Less>
547 value_type * get_with( Q const& key, Less pred ) const
550 leaf_node * pNode = base_class::get_with( key,
551 cds::details::predicate_wrapper< leaf_node, Less, typename maker::value_accessor >());
552 return pNode ? &pNode->m_Value : nullptr;
555 /// Clears the set (non-atomic)
557 The function unlink all items from the tree.
558 The function is not atomic, thus, in multi-threaded environment with parallel insertions
562 assert( set.empty() );
564 the assertion could be raised.
566 For each leaf the \ref disposer will be called after unlinking.
568 RCU \p synchronize method can be called. RCU should not be locked.
575 /// Checks if the set is empty
578 return base_class::empty();
581 /// Returns item count in the set
583 Only leaf nodes containing user data are counted.
585 The value returned depends on item counter type provided by \p Traits template parameter.
586 If it is \p atomicity::empty_item_counter \p %size() always returns 0.
587 Therefore, the function is not suitable for checking the tree emptiness, use \p empty()
588 member function for this purpose.
592 return base_class::size();
595 /// Returns const reference to internal statistics
596 stat const& statistics() const
598 return base_class::statistics();
601 /// Checks internal consistency (not atomic, not thread-safe)
603 The debugging function to check internal consistency of the tree.
605 bool check_consistency() const
607 return base_class::check_consistency();
610 }} // namespace cds::container
612 #endif // #ifndef CDSLIB_CONTAINER_ELLEN_BINTREE_SET_RCU_H