--- /dev/null
+/*
+ This file is a part of libcds - Concurrent Data Structures library
+
+ (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
+
+ Source code repo: http://github.com/khizmax/libcds/
+ Download: http://sourceforge.net/projects/libcds/files/
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice, this
+ list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright notice,
+ this list of conditions and the following disclaimer in the documentation
+ and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef CDSLIB_INTRUSIVE_IMPL_MICHAEL_LIST_H
+#define CDSLIB_INTRUSIVE_IMPL_MICHAEL_LIST_H
+
+#include <cds/intrusive/details/michael_list_base.h>
+#include <cds/details/make_const_type.h>
+
+namespace cds { namespace intrusive {
+
+ /// Michael's lock-free ordered single-linked list
+ /** @ingroup cds_intrusive_list
+ \anchor cds_intrusive_MichaelList_hp
+
+ Usually, ordered single-linked list is used as a building block for the hash table implementation.
+ The complexity of searching is <tt>O(N)</tt>.
+
+ Source:
+ - [2002] Maged Michael "High performance dynamic lock-free hash tables and list-based sets"
+
+ Template arguments:
+ - \p GC - Garbage collector used. Note the \p GC must be the same as the GC used for item type \p T (see \p michael_list::node).
+ - \p T - type to be stored in the list. The type must be based on \p michael_list::node (for \p michael_list::base_hook)
+ or it must have a member of type \p michael_list::node (for \p michael_list::member_hook).
+ - \p Traits - type traits, default is \p michael_list::traits. It is possible to declare option-based
+ list with \p cds::intrusive::michael_list::make_traits metafunction:
+ For example, the following traits-based declaration of \p gc::HP Michael's list
+ \code
+ #include <cds/intrusive/michael_list_hp.h>
+ // Declare item stored in your list
+ struct item: public cds::intrusive::michael_list::node< cds::gc::HP >
+ {
+ int nKey;
+ // .... other data
+ };
+
+ // Declare comparator for the item
+ struct my_compare {
+ int operator()( item const& i1, item const& i2 ) const
+ {
+ return i1.nKey - i2.nKey;
+ }
+ };
+
+ // Declare traits
+ struct my_traits: public cds::intrusive::michael_list::traits
+ {
+ typedef cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::HP > > hook;
+ typedef my_compare compare;
+ };
+
+ // Declare traits-based list
+ typedef cds::intrusive::MichaelList< cds::gc::HP, item, my_traits > traits_based_list;
+ \endcode
+ is equivalent for the following option-based list
+ \code
+ #include <cds/intrusive/michael_list_hp.h>
+
+ // item struct and my_compare are the same
+
+ // Declare option-based list
+ typedef cds::intrusive::MichaelList< cds::gc::HP, item,
+ typename cds::intrusive::michael_list::make_traits<
+ cds::intrusive::opt::hook< cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::HP > > > // hook option
+ ,cds::intrusive::opt::compare< my_compare > // item comparator option
+ >::type
+ > option_based_list;
+ \endcode
+
+ \par Usage
+ There are different specializations of this template for each garbage collecting schema.
+ You should select GC needed and include appropriate .h-file:
+ - for \p gc::HP: <tt> <cds/intrusive/michael_list_hp.h> </tt>
+ - for \p gc::DHP: <tt> <cds/intrusive/michael_list_dhp.h> </tt>
+ - for \ref cds_urcu_gc "RCU type" - see \ref cds_intrusive_MichaelList_rcu "RCU-based MichaelList"
+ - for \p gc::nogc: <tt> <cds/intrusive/michael_list_nogc.h> </tt>
+ See \ref cds_intrusive_MichaelList_nogc "non-GC MichaelList"
+
+ Then, you should incorporate \p michael_list::node into your struct \p T and provide
+ appropriate \p michael_list::traits::hook in your \p Traits template parameters. Usually, for \p Traits you
+ define a struct based on \p michael_list::traits.
+
+ Example for \p gc::DHP and base hook:
+ \code
+ // Include GC-related Michael's list specialization
+ #include <cds/intrusive/michael_list_dhp.h>
+
+ // Data stored in Michael's list
+ struct my_data: public cds::intrusive::michael_list::node< cds::gc::DHP >
+ {
+ // key field
+ std::string strKey;
+
+ // other data
+ // ...
+ };
+
+ // my_data comparing functor
+ struct my_data_cmp {
+ int operator()( const my_data& d1, const my_data& d2 )
+ {
+ return d1.strKey.compare( d2.strKey );
+ }
+
+ int operator()( const my_data& d, const std::string& s )
+ {
+ return d.strKey.compare(s);
+ }
+
+ int operator()( const std::string& s, const my_data& d )
+ {
+ return s.compare( d.strKey );
+ }
+ };
+
+
+ // Declare traits
+ struct my_traits: public cds::intrusive::michael_list::traits
+ {
+ typedef cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::DHP > > hook;
+ typedef my_data_cmp compare;
+ };
+
+ // Declare list type
+ typedef cds::intrusive::MichaelList< cds::gc::DHP, my_data, my_traits > traits_based_list;
+ \endcode
+
+ Equivalent option-based code:
+ \code
+ // GC-related specialization
+ #include <cds/intrusive/michael_list_dhp.h>
+
+ struct my_data {
+ // see above
+ };
+ struct compare {
+ // see above
+ };
+
+ // Declare option-based list
+ typedef cds::intrusive::MichaelList< cds::gc::DHP
+ ,my_data
+ , typename cds::intrusive::michael_list::make_traits<
+ cds::intrusive::opt::hook< cds::intrusive::michael_list::base_hook< cds::opt::gc< cds::gc::DHP > > >
+ ,cds::intrusive::opt::compare< my_data_cmp >
+ >::type
+ > option_based_list;
+
+ \endcode
+ */
+ template <
+ class GC
+ ,typename T
+#ifdef CDS_DOXYGEN_INVOKED
+ ,class Traits = michael_list::traits
+#else
+ ,class Traits
+#endif
+ >
+ class MichaelList
+ {
+ public:
+ typedef T value_type; ///< type of value stored in the list
+ typedef Traits traits; ///< Traits template parameter
+
+ typedef typename traits::hook hook; ///< hook type
+ typedef typename hook::node_type node_type; ///< node type
+
+# ifdef CDS_DOXYGEN_INVOKED
+ typedef implementation_defined key_comparator ; ///< key comparison functor based on opt::compare and opt::less option setter.
+# else
+ typedef typename opt::details::make_comparator< value_type, traits >::type key_comparator;
+# endif
+
+ typedef typename traits::disposer disposer; ///< disposer used
+ typedef typename traits::stat stat; ///< Internal statistics
+ typedef typename get_node_traits< value_type, node_type, hook>::type node_traits ; ///< node traits
+ typedef typename michael_list::get_link_checker< node_type, traits::link_checker >::type link_checker; ///< link checker
+
+ typedef GC gc ; ///< Garbage collector
+ typedef typename traits::back_off back_off; ///< back-off strategy
+ typedef typename traits::item_counter item_counter; ///< Item counting policy used
+ typedef typename traits::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
+
+ typedef typename gc::template guarded_ptr< value_type > guarded_ptr; ///< Guarded pointer
+
+ static constexpr const size_t c_nHazardPtrCount = 4; ///< Count of hazard pointer required for the algorithm
+
+ //@cond
+ // Rebind traits (split-list support)
+ template <typename... Options>
+ struct rebind_traits {
+ typedef MichaelList<
+ gc
+ , value_type
+ , typename cds::opt::make_options< traits, Options...>::type
+ > type;
+ };
+
+ // Stat selector
+ template <typename Stat>
+ using select_stat_wrapper = michael_list::select_stat_wrapper< Stat >;
+ //@endcond
+
+ protected:
+ typedef typename node_type::atomic_marked_ptr atomic_node_ptr; ///< Atomic node pointer
+ typedef typename node_type::marked_ptr marked_node_ptr; ///< Node marked pointer
+
+ typedef atomic_node_ptr auxiliary_head; ///< Auxiliary head type (for split-list support)
+
+ atomic_node_ptr m_pHead; ///< Head pointer
+ item_counter m_ItemCounter; ///< Item counter
+ stat m_Stat; ///< Internal statistics
+
+ //@cond
+ /// Position pointer for item search
+ struct position {
+ atomic_node_ptr * pPrev ; ///< Previous node
+ node_type * pCur ; ///< Current node
+ node_type * pNext ; ///< Next node
+
+ typename gc::template GuardArray<3> guards ; ///< Guards array
+
+ enum {
+ guard_prev_item,
+ guard_current_item,
+ guard_next_item
+ };
+ };
+
+ struct clean_disposer {
+ void operator()( value_type * p )
+ {
+ michael_list::node_cleaner<gc, node_type, memory_model>()( node_traits::to_node_ptr( p ));
+ disposer()( p );
+ }
+ };
+ //@endcond
+
+ protected:
+ //@cond
+ static void retire_node( node_type * pNode )
+ {
+ assert( pNode != nullptr );
+ gc::template retire<clean_disposer>( node_traits::to_value_ptr( *pNode ));
+ }
+
+ static bool link_node( node_type * pNode, position& pos )
+ {
+ assert( pNode != nullptr );
+ link_checker::is_empty( pNode );
+
+ marked_node_ptr cur(pos.pCur);
+ pNode->m_pNext.store( cur, memory_model::memory_order_release );
+ if ( cds_likely( pos.pPrev->compare_exchange_strong( cur, marked_node_ptr(pNode), memory_model::memory_order_release, atomics::memory_order_relaxed )))
+ return true;
+
+ pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ return false;
+ }
+
+ static bool unlink_node( position& pos )
+ {
+ assert( pos.pPrev != nullptr );
+ assert( pos.pCur != nullptr );
+
+ // Mark the node (logical deleting)
+ marked_node_ptr next(pos.pNext, 0);
+ if ( cds_likely( pos.pCur->m_pNext.compare_exchange_strong( next, marked_node_ptr(pos.pNext, 1), memory_model::memory_order_release, atomics::memory_order_relaxed ))) {
+ // physical deletion may be performed by search function if it detects that a node is logically deleted (marked)
+ // CAS may be successful here or in other thread that searching something
+ marked_node_ptr cur(pos.pCur);
+ if ( cds_likely( pos.pPrev->compare_exchange_strong( cur, marked_node_ptr( pos.pNext ), memory_model::memory_order_acquire, atomics::memory_order_relaxed )))
+ retire_node( pos.pCur );
+ return true;
+ }
+ return false;
+ }
+ //@endcond
+
+ protected:
+ //@cond
+ template <bool IsConst>
+ class iterator_type
+ {
+ friend class MichaelList;
+
+ protected:
+ value_type * m_pNode;
+ typename gc::Guard m_Guard;
+
+ void next()
+ {
+ if ( m_pNode ) {
+ typename gc::Guard g;
+ node_type * pCur = node_traits::to_node_ptr( *m_pNode );
+
+ marked_node_ptr pNext;
+ do {
+ pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed);
+ g.assign( node_traits::to_value_ptr( pNext.ptr()));
+ } while ( cds_unlikely( pNext != pCur->m_pNext.load(memory_model::memory_order_acquire)));
+
+ if ( pNext.ptr())
+ m_pNode = m_Guard.assign( g.template get<value_type>());
+ else {
+ m_pNode = nullptr;
+ m_Guard.clear();
+ }
+ }
+ }
+
+ iterator_type( atomic_node_ptr const& pNode )
+ {
+ for (;;) {
+ marked_node_ptr p = pNode.load(memory_model::memory_order_relaxed);
+ if ( p.ptr()) {
+ m_pNode = m_Guard.assign( node_traits::to_value_ptr( p.ptr()));
+ }
+ else {
+ m_pNode = nullptr;
+ m_Guard.clear();
+ }
+ if ( cds_likely( p == pNode.load(memory_model::memory_order_acquire)))
+ break;
+ }
+ }
+
+ public:
+ typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
+ typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
+
+ iterator_type()
+ : m_pNode( nullptr )
+ {}
+
+ iterator_type( iterator_type const& src )
+ {
+ if ( src.m_pNode ) {
+ m_pNode = m_Guard.assign( src.m_pNode );
+ }
+ else
+ m_pNode = nullptr;
+ }
+
+ value_ptr operator ->() const
+ {
+ return m_pNode;
+ }
+
+ value_ref operator *() const
+ {
+ assert( m_pNode != nullptr );
+ return *m_pNode;
+ }
+
+ /// Pre-increment
+ iterator_type& operator ++()
+ {
+ next();
+ return *this;
+ }
+
+ iterator_type& operator = (iterator_type const& src)
+ {
+ m_pNode = src.m_pNode;
+ m_Guard.assign( m_pNode );
+ return *this;
+ }
+
+ /*
+ /// Post-increment
+ void operator ++(int)
+ {
+ next();
+ }
+ */
+
+ template <bool C>
+ bool operator ==(iterator_type<C> const& i ) const
+ {
+ return m_pNode == i.m_pNode;
+ }
+ template <bool C>
+ bool operator !=(iterator_type<C> const& i ) const
+ {
+ return m_pNode != i.m_pNode;
+ }
+ };
+ //@endcond
+
+ public:
+ ///@name Forward iterators (only for debugging purpose)
+ //@{
+ /// Forward iterator
+ /**
+ The forward iterator for Michael's list has some features:
+ - it has no post-increment operator
+ - to protect the value, the iterator contains a GC-specific guard + another guard is required locally for increment operator.
+ For some GC (like as \p gc::HP), a guard is a limited resource per thread, so an exception (or assertion) "no free guard"
+ may be thrown if the limit of guard count per thread is exceeded.
+ - The iterator cannot be moved across thread boundary since it contains thread-private GC's guard.
+ - Iterator ensures thread-safety even if you delete the item the iterator points to. However, in case of concurrent
+ deleting operations there is no guarantee that you iterate all item in the list.
+ Moreover, a crash is possible when you try to iterate the next element that has been deleted by concurrent thread.
+
+ @warning Use this iterator on the concurrent container for debugging purpose only.
+
+ The iterator interface:
+ \code
+ class iterator {
+ public:
+ // Default constructor
+ iterator();
+
+ // Copy construtor
+ iterator( iterator const& src );
+
+ // Dereference operator
+ value_type * operator ->() const;
+
+ // Dereference operator
+ value_type& operator *() const;
+
+ // Preincrement operator
+ iterator& operator ++();
+
+ // Assignment operator
+ iterator& operator = (iterator const& src);
+
+ // Equality operators
+ bool operator ==(iterator const& i ) const;
+ bool operator !=(iterator const& i ) const;
+ };
+ \endcode
+ */
+ typedef iterator_type<false> iterator;
+ /// Const forward iterator
+ /**
+ For iterator's features and requirements see \ref iterator
+ */
+ typedef iterator_type<true> const_iterator;
+
+ /// Returns a forward iterator addressing the first element in a list
+ /**
+ For empty list \code begin() == end() \endcode
+ */
+ iterator begin()
+ {
+ return iterator( m_pHead );
+ }
+
+ /// Returns an iterator that addresses the location succeeding the last element in a list
+ /**
+ Do not use the value returned by <tt>end</tt> function to access any item.
+ Internally, <tt>end</tt> returning value equals to \p nullptr.
+
+ The returned value can be used only to control reaching the end of the list.
+ For empty list <tt>begin() == end()</tt>
+ */
+ iterator end()
+ {
+ return iterator();
+ }
+
+ /// Returns a forward const iterator addressing the first element in a list
+ const_iterator cbegin() const
+ {
+ return const_iterator( m_pHead );
+ }
+
+ /// Returns a forward const iterator addressing the first element in a list
+ const_iterator begin() const
+ {
+ return const_iterator( m_pHead );
+ }
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a list
+ const_iterator end() const
+ {
+ return const_iterator();
+ }
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a list
+ const_iterator cend() const
+ {
+ return const_iterator();
+ }
+ //@}
+
+ public:
+ /// Default constructor initializes empty list
+ MichaelList()
+ : m_pHead( nullptr )
+ {
+ static_assert( (std::is_same< gc, typename node_type::gc >::value), "GC and node_type::gc must be the same type" );
+ }
+
+ //@cond
+ template <typename Stat, typename = std::enable_if<std::is_same<stat, michael_list::wrapped_stat<Stat>>::value >>
+ explicit MichaelList( Stat& st )
+ : m_pHead( nullptr )
+ , m_Stat( st )
+ {}
+ //@endcond
+
+ /// Destroys the list object
+ ~MichaelList()
+ {
+ clear();
+ }
+
+ /// Inserts new node
+ /**
+ The function inserts \p val into the list if the list does not contain
+ an item with key equal to \p val.
+
+ Returns \p true if \p val has been linked to the list, \p false otherwise.
+ */
+ bool insert( value_type& val )
+ {
+ return insert_at( m_pHead, val );
+ }
+
+ /// Inserts new node
+ /**
+ This function is intended for derived non-intrusive containers.
+
+ The function allows to split new item creating into two part:
+ - create item with key only
+ - insert new item into the list
+ - if inserting is success, calls \p f functor to initialize value-field of \p val.
+
+ The functor signature is:
+ \code
+ void func( value_type& val );
+ \endcode
+ where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
+ \p val no any other changes could be made on this list's item by concurrent threads.
+ The user-defined functor is called only if the inserting is success.
+
+ @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
+ */
+ template <typename Func>
+ bool insert( value_type& val, Func f )
+ {
+ return insert_at( m_pHead, val, f );
+ }
+
+ /// Updates the node
+ /**
+ The operation performs inserting or changing data with lock-free manner.
+
+ If the item \p val is not found in the list, then \p val is inserted
+ iff \p bInsert is \p true.
+ Otherwise, the functor \p func is called with item found.
+ The functor signature is:
+ \code
+ void func( bool bNew, value_type& item, value_type& val );
+ \endcode
+ with arguments:
+ - \p bNew - \p true if the item has been inserted, \p false otherwise
+ - \p item - item of the list
+ - \p val - argument \p val passed into the \p update() function
+ If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
+ refers to the same thing.
+
+ The functor may change non-key fields of the \p item; however, \p func must guarantee
+ that during changing no any other modifications could be made on this item by concurrent threads.
+
+ Returns std::pair<bool, bool> where \p first is \p true if operation is successful,
+ \p second is \p true if new item has been added or \p false if the item with that key
+ already in the list.
+
+ @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
+ */
+ template <typename Func>
+ std::pair<bool, bool> update( value_type& val, Func func, bool bInsert = true )
+ {
+ return update_at( m_pHead, val, func, bInsert );
+ }
+
+ //@cond
+ template <typename Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
+ std::pair<bool, bool> ensure( value_type& val, Func func )
+ {
+ return update( val, func, true );
+ }
+ //@endcond
+
+ /// Unlinks the item \p val from the list
+ /**
+ The function searches the item \p val in the list and unlinks it from the list
+ if it is found and it is equal to \p val.
+
+ Difference between \p erase() and \p %unlink(): \p %erase() finds <i>a key</i>
+ and deletes the item found. \p %unlink() finds an item by key and deletes it
+ only if \p val is an item of the list, i.e. the pointer to item found
+ is equal to <tt> &val </tt>.
+
+ \p disposer specified in \p Traits is called for deleted item.
+
+ The function returns \p true if success and \p false otherwise.
+ */
+ bool unlink( value_type& val )
+ {
+ return unlink_at( m_pHead, val );
+ }
+
+ /// Deletes the item from the list
+ /** \anchor cds_intrusive_MichaelList_hp_erase_val
+ The function searches an item with key equal to \p key in the list,
+ unlinks it from the list, and returns \p true.
+ If \p key is not found the function return \p false.
+
+ \p disposer specified in \p Traits is called for deleted item.
+ */
+ template <typename Q>
+ bool erase( Q const& key )
+ {
+ return erase_at( m_pHead, key, key_comparator());
+ }
+
+ /// Deletes the item from the list using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_intrusive_MichaelList_hp_erase_val "erase(Q const&)"
+ but \p pred is used for key comparing.
+ \p Less functor has the interface like \p std::less.
+ \p pred must imply the same element order as the comparator used for building the list.
+
+ \p disposer specified in \p Traits is called for deleted item.
+ */
+ template <typename Q, typename Less>
+ bool erase_with( Q const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return erase_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+
+ /// Deletes the item from the list
+ /** \anchor cds_intrusive_MichaelList_hp_erase_func
+ The function searches an item with key equal to \p key in the list,
+ call \p func functor with item found, unlinks it from the list, and returns \p true.
+ The \p Func interface is
+ \code
+ struct functor {
+ void operator()( value_type const& item );
+ };
+ \endcode
+ If \p key is not found the function return \p false, \p func is not called.
+
+ \p disposer specified in \p Traits is called for deleted item.
+ */
+ template <typename Q, typename Func>
+ bool erase( Q const& key, Func func )
+ {
+ return erase_at( m_pHead, key, key_comparator(), func );
+ }
+
+ /// Deletes the item from the list using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_intrusive_MichaelList_hp_erase_func "erase(Q const&, Func)"
+ but \p pred is used for key comparing.
+ \p Less functor has the interface like \p std::less.
+ \p pred must imply the same element order as the comparator used for building the list.
+
+ \p disposer specified in \p Traits is called for deleted item.
+ */
+ template <typename Q, typename Less, typename Func>
+ bool erase_with( Q const& key, Less pred, Func f )
+ {
+ CDS_UNUSED( pred );
+ return erase_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
+ }
+
+ /// Extracts the item from the list with specified \p key
+ /** \anchor cds_intrusive_MichaelList_hp_extract
+ The function searches an item with key equal to \p key,
+ unlinks it from the list, and returns it as \p guarded_ptr.
+ If \p key is not found returns an empty guarded pointer.
+
+ Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
+
+ The \ref disposer specified in \p Traits class template parameter is called automatically
+ by garbage collector \p GC when returned \ref guarded_ptr object will be destroyed or released.
+ @note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
+
+ Usage:
+ \code
+ typedef cds::intrusive::MichaelList< cds::gc::HP, foo, my_traits > ord_list;
+ ord_list theList;
+ // ...
+ {
+ ord_list::guarded_ptr gp(theList.extract( 5 ));
+ if ( gp ) {
+ // Deal with gp
+ // ...
+ }
+ // Destructor of gp releases internal HP guard
+ }
+ \endcode
+ */
+ template <typename Q>
+ guarded_ptr extract( Q const& key )
+ {
+ return extract_at( m_pHead, key, key_comparator());
+ }
+
+ /// Extracts the item using compare functor \p pred
+ /**
+ The function is an analog of \ref cds_intrusive_MichaelList_hp_extract "extract(Q const&)"
+ but \p pred predicate is used for key comparing.
+
+ \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
+ in any order.
+ \p pred must imply the same element order as the comparator used for building the list.
+ */
+ template <typename Q, typename Less>
+ guarded_ptr extract_with( Q const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return extract_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+
+ /// Finds \p key in the list
+ /** \anchor cds_intrusive_MichaelList_hp_find_func
+ The function searches the item with key equal to \p key and calls the functor \p f for item found.
+ The interface of \p Func functor is:
+ \code
+ struct functor {
+ void operator()( value_type& item, Q& key );
+ };
+ \endcode
+ where \p item is the item found, \p key is the <tt>find</tt> function argument.
+
+ The functor may change non-key fields of \p item. Note that the function is only guarantee
+ that \p item cannot be disposed during functor is executing.
+ The function does not serialize simultaneous access to the \p item. If such access is
+ possible you must provide your own synchronization schema to keep out unsafe item modifications.
+
+ The \p key argument is non-const since it can be used as \p f functor destination i.e., the functor
+ may modify both arguments.
+
+ The function returns \p true if \p val is found, \p false otherwise.
+ */
+ template <typename Q, typename Func>
+ bool find( Q& key, Func f )
+ {
+ return find_at( m_pHead, key, key_comparator(), f );
+ }
+ //@cond
+ template <typename Q, typename Func>
+ bool find( Q const& key, Func f )
+ {
+ return find_at( m_pHead, key, key_comparator(), f );
+ }
+ //@endcond
+
+ /// Finds the \p key using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_intrusive_MichaelList_hp_find_func "find(Q&, Func)"
+ but \p pred is used for key comparing.
+ \p Less functor has the interface like \p std::less.
+ \p pred must imply the same element order as the comparator used for building the list.
+ */
+ template <typename Q, typename Less, typename Func>
+ bool find_with( Q& key, Less pred, Func f )
+ {
+ CDS_UNUSED( pred );
+ return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
+ }
+ //@cond
+ template <typename Q, typename Less, typename Func>
+ bool find_with( Q const& key, Less pred, Func f )
+ {
+ CDS_UNUSED( pred );
+ return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
+ }
+ //@endcond
+
+ /// Checks whether the list contains \p key
+ /**
+ The function searches the item with key equal to \p key
+ and returns \p true if it is found, and \p false otherwise.
+ */
+ template <typename Q>
+ bool contains( Q const& key )
+ {
+ return find_at( m_pHead, key, key_comparator());
+ }
+ //@cond
+ template <typename Q>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( Q const& key )
+ {
+ return contains( key );
+ }
+ //@endcond
+
+ /// Checks whether the list contains \p key using \p pred predicate for searching
+ /**
+ The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
+ \p Less functor has the interface like \p std::less.
+ \p Less must imply the same element order as the comparator used for building the list.
+ */
+ template <typename Q, typename Less>
+ bool contains( Q const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+ //@cond
+ template <typename Q, typename Less>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find_with( Q const& key, Less pred )
+ {
+ return contains( key, pred );
+ }
+ //@endcond
+
+ /// Finds the \p key and return the item found
+ /** \anchor cds_intrusive_MichaelList_hp_get
+ The function searches the item with key equal to \p key
+ and returns it as \p guarded_ptr.
+ If \p key is not found the function returns an empty guarded pointer.
+
+ The \ref disposer specified in \p Traits class template parameter is called
+ by garbage collector \p GC automatically when returned \ref guarded_ptr object
+ will be destroyed or released.
+ @note Each \p guarded_ptr object uses one GC's guard which can be limited resource.
+
+ Usage:
+ \code
+ typedef cds::intrusive::MichaelList< cds::gc::HP, foo, my_traits > ord_list;
+ ord_list theList;
+ // ...
+ {
+ ord_list::guarded_ptr gp(theList.get( 5 ));
+ if ( gp ) {
+ // Deal with gp
+ //...
+ }
+ // Destructor of guarded_ptr releases internal HP guard
+ }
+ \endcode
+
+ Note the compare functor specified for \p Traits template parameter
+ should accept a parameter of type \p Q that can be not the same as \p value_type.
+ */
+ template <typename Q>
+ guarded_ptr get( Q const& key )
+ {
+ return get_at( m_pHead, key, key_comparator());
+ }
+
+ /// Finds the \p key and return the item found
+ /**
+ The function is an analog of \ref cds_intrusive_MichaelList_hp_get "get( Q const&)"
+ but \p pred is used for comparing the keys.
+
+ \p Less functor has the semantics like \p std::less but should take arguments of type \ref value_type and \p Q
+ in any order.
+ \p pred must imply the same element order as the comparator used for building the list.
+ */
+ template <typename Q, typename Less>
+ guarded_ptr get_with( Q const& key, Less pred )
+ {
+ CDS_UNUSED( pred );
+ return get_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+
+ /// Clears the list
+ /**
+ The function unlink all items from the list.
+ */
+ void clear()
+ {
+ typename gc::Guard guard;
+ marked_node_ptr head;
+ while ( true ) {
+ head = m_pHead.load(memory_model::memory_order_relaxed);
+ if ( head.ptr())
+ guard.assign( node_traits::to_value_ptr( *head.ptr()));
+ if ( cds_likely( m_pHead.load(memory_model::memory_order_acquire) == head )) {
+ if ( head.ptr() == nullptr )
+ break;
+ value_type& val = *node_traits::to_value_ptr( *head.ptr());
+ unlink( val );
+ }
+ }
+ }
+
+ /// Checks whether the list is empty
+ bool empty() const
+ {
+ return m_pHead.load( memory_model::memory_order_relaxed ).all() == nullptr;
+ }
+
+ /// Returns list's item count
+ /**
+ The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
+ this function always returns 0.
+
+ @note Even if you use real item counter and it returns 0, this fact does not mean that the list
+ is empty. To check list emptiness use \p empty() method.
+ */
+ size_t size() const
+ {
+ return m_ItemCounter.value();
+ }
+
+ /// Returns const reference to internal statistics
+ stat const& statistics() const
+ {
+ return m_Stat;
+ }
+
+ protected:
+ //@cond
+ // split-list support
+ bool insert_aux_node( node_type * pNode )
+ {
+ return insert_aux_node( m_pHead, pNode );
+ }
+
+ // split-list support
+ bool insert_aux_node( atomic_node_ptr& refHead, node_type * pNode )
+ {
+ assert( pNode != nullptr );
+
+ // Hack: convert node_type to value_type.
+ // In principle, auxiliary node can be non-reducible to value_type
+ // We assume that comparator can correctly distinguish aux and regular node.
+ return insert_at( refHead, *node_traits::to_value_ptr( pNode ));
+ }
+
+ bool insert_at( atomic_node_ptr& refHead, value_type& val )
+ {
+ node_type * pNode = node_traits::to_node_ptr( val );
+ position pos;
+
+ while ( true ) {
+ if ( search( refHead, val, pos, key_comparator())) {
+ m_Stat.onInsertFailed();
+ return false;
+ }
+
+ if ( link_node( pNode, pos )) {
+ ++m_ItemCounter;
+ m_Stat.onInsertSuccess();
+ return true;
+ }
+
+ m_Stat.onInsertRetry();
+ }
+ }
+
+ template <typename Func>
+ bool insert_at( atomic_node_ptr& refHead, value_type& val, Func f )
+ {
+ node_type * pNode = node_traits::to_node_ptr( val );
+ position pos;
+
+ while ( true ) {
+ if ( search( refHead, val, pos, key_comparator())) {
+ m_Stat.onInsertFailed();
+ return false;
+ }
+
+ typename gc::Guard guard;
+ guard.assign( &val );
+ if ( link_node( pNode, pos )) {
+ f( val );
+ ++m_ItemCounter;
+ m_Stat.onInsertSuccess();
+ return true;
+ }
+
+ m_Stat.onInsertRetry();
+ }
+ }
+
+ template <typename Func>
+ std::pair<bool, bool> update_at( atomic_node_ptr& refHead, value_type& val, Func func, bool bInsert )
+ {
+ position pos;
+
+ node_type * pNode = node_traits::to_node_ptr( val );
+ while ( true ) {
+ if ( search( refHead, val, pos, key_comparator())) {
+ if ( cds_unlikely( pos.pCur->m_pNext.load(memory_model::memory_order_acquire).bits())) {
+ back_off()();
+ m_Stat.onUpdateMarked();
+ continue; // the node found is marked as deleted
+ }
+ assert( key_comparator()( val, *node_traits::to_value_ptr( *pos.pCur )) == 0 );
+
+ func( false, *node_traits::to_value_ptr( *pos.pCur ) , val );
+ m_Stat.onUpdateExisting();
+ return std::make_pair( true, false );
+ }
+ else {
+ if ( !bInsert ) {
+ m_Stat.onUpdateFailed();
+ return std::make_pair( false, false );
+ }
+
+ typename gc::Guard guard;
+ guard.assign( &val );
+ if ( link_node( pNode, pos )) {
+ ++m_ItemCounter;
+ func( true, val, val );
+ m_Stat.onUpdateNew();
+ return std::make_pair( true, true );
+ }
+ }
+
+ m_Stat.onUpdateRetry();
+ }
+ }
+
+ bool unlink_at( atomic_node_ptr& refHead, value_type& val )
+ {
+ position pos;
+
+ back_off bkoff;
+ while ( search( refHead, val, pos, key_comparator())) {
+ if ( node_traits::to_value_ptr( *pos.pCur ) == &val ) {
+ if ( unlink_node( pos )) {
+ --m_ItemCounter;
+ m_Stat.onEraseSuccess();
+ return true;
+ }
+ else
+ bkoff();
+ }
+ else {
+ m_Stat.onUpdateFailed();
+ break;
+ }
+
+ m_Stat.onEraseRetry();
+ }
+
+ m_Stat.onEraseFailed();
+ return false;
+ }
+
+ template <typename Q, typename Compare, typename Func>
+ bool erase_at( atomic_node_ptr& refHead, const Q& val, Compare cmp, Func f, position& pos )
+ {
+ back_off bkoff;
+ while ( search( refHead, val, pos, cmp )) {
+ if ( unlink_node( pos )) {
+ f( *node_traits::to_value_ptr( *pos.pCur ));
+ --m_ItemCounter;
+ m_Stat.onEraseSuccess();
+ return true;
+ }
+ else
+ bkoff();
+
+ m_Stat.onEraseRetry();
+ }
+
+ m_Stat.onEraseFailed();
+ return false;
+ }
+
+ template <typename Q, typename Compare, typename Func>
+ bool erase_at( atomic_node_ptr& refHead, const Q& val, Compare cmp, Func f )
+ {
+ position pos;
+ return erase_at( refHead, val, cmp, f, pos );
+ }
+
+ template <typename Q, typename Compare>
+ bool erase_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
+ {
+ position pos;
+ return erase_at( refHead, val, cmp, [](value_type const&){}, pos );
+ }
+
+ template <typename Q, typename Compare>
+ guarded_ptr extract_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
+ {
+ position pos;
+ back_off bkoff;
+ while ( search( refHead, val, pos, cmp )) {
+ if ( unlink_node( pos )) {
+ --m_ItemCounter;
+ m_Stat.onEraseSuccess();
+ return guarded_ptr( pos.guards.release( position::guard_current_item ));
+ }
+ else
+ bkoff();
+ m_Stat.onEraseRetry();
+ }
+
+ m_Stat.onEraseFailed();
+ return guarded_ptr();
+ }
+
+ template <typename Q, typename Compare>
+ bool find_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
+ {
+ position pos;
+ if ( search( refHead, val, pos, cmp )) {
+ m_Stat.onFindSuccess();
+ return true;
+ }
+
+ m_Stat.onFindFailed();
+ return false;
+ }
+
+ template <typename Q, typename Compare, typename Func>
+ bool find_at( atomic_node_ptr& refHead, Q& val, Compare cmp, Func f )
+ {
+ position pos;
+ if ( search( refHead, val, pos, cmp )) {
+ f( *node_traits::to_value_ptr( *pos.pCur ), val );
+ m_Stat.onFindSuccess();
+ return true;
+ }
+
+ m_Stat.onFindFailed();
+ return false;
+ }
+
+ template <typename Q, typename Compare>
+ guarded_ptr get_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
+ {
+ position pos;
+ if ( search( refHead, val, pos, cmp )) {
+ m_Stat.onFindSuccess();
+ return guarded_ptr( pos.guards.release( position::guard_current_item ));
+ }
+
+ m_Stat.onFindFailed();
+ return guarded_ptr();
+ }
+
+ // split-list support
+ template <typename Predicate>
+ void destroy( Predicate /*pred*/ )
+ {
+ clear();
+ }
+
+ //@endcond
+
+ protected:
+
+ //@cond
+ template <typename Q, typename Compare >
+ bool search( atomic_node_ptr& refHead, const Q& val, position& pos, Compare cmp )
+ {
+ atomic_node_ptr * pPrev;
+ marked_node_ptr pNext;
+ marked_node_ptr pCur;
+
+ back_off bkoff;
+
+ try_again:
+ pPrev = &refHead;
+ pNext = nullptr;
+
+ pCur = pos.guards.protect( position::guard_current_item, *pPrev,
+ [](marked_node_ptr p) -> value_type *
+ {
+ return node_traits::to_value_ptr( p.ptr());
+ });
+
+ while ( true ) {
+ if ( pCur.ptr() == nullptr ) {
+ pos.pPrev = pPrev;
+ pos.pCur = nullptr;
+ pos.pNext = nullptr;
+ return false;
+ }
+
+ pNext = pos.guards.protect( position::guard_next_item, pCur->m_pNext,
+ [](marked_node_ptr p ) -> value_type *
+ {
+ return node_traits::to_value_ptr( p.ptr());
+ });
+ if ( cds_unlikely( pPrev->load(memory_model::memory_order_acquire).all() != pCur.ptr())) {
+ bkoff();
+ goto try_again;
+ }
+
+ // pNext contains deletion mark for pCur
+ if ( pNext.bits() == 1 ) {
+ // pCur marked i.e. logically deleted. Help the erase/unlink function to unlink pCur node
+ marked_node_ptr cur( pCur.ptr());
+ if ( cds_unlikely( pPrev->compare_exchange_strong( cur, marked_node_ptr( pNext.ptr()), memory_model::memory_order_acquire, atomics::memory_order_relaxed ))) {
+ retire_node( pCur.ptr());
+ m_Stat.onHelpingSuccess();
+ }
+ else {
+ bkoff();
+ m_Stat.onHelpingFailed();
+ goto try_again;
+ }
+ }
+ else {
+ assert( pCur.ptr() != nullptr );
+ int nCmp = cmp( *node_traits::to_value_ptr( pCur.ptr()), val );
+ if ( nCmp >= 0 ) {
+ pos.pPrev = pPrev;
+ pos.pCur = pCur.ptr();
+ pos.pNext = pNext.ptr();
+ return nCmp == 0;
+ }
+ pPrev = &( pCur->m_pNext );
+ pos.guards.copy( position::guard_prev_item, position::guard_current_item );
+ }
+ pCur = pNext;
+ pos.guards.copy( position::guard_current_item, position::guard_next_item );
+ }
+ }
+ //@endcond
+ };
+}} // namespace cds::intrusive
+
+#endif // #ifndef CDSLIB_INTRUSIVE_IMPL_MICHAEL_LIST_H
projects / c11concurrency-benchmarks.git / blobdiff