+/*
+ 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_LAZY_LIST_H
+#define CDSLIB_INTRUSIVE_IMPL_LAZY_LIST_H
+
+#include <mutex> // unique_lock
+#include <cds/intrusive/details/lazy_list_base.h>
+
+namespace cds { namespace intrusive {
+
+ /// Lazy ordered single-linked list
+ /** @ingroup cds_intrusive_list
+ \anchor cds_intrusive_LazyList_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:
+ - [2005] Steve Heller, Maurice Herlihy, Victor Luchangco, Mark Moir, William N. Scherer III, and Nir Shavit
+ "A Lazy Concurrent List-Based Set Algorithm"
+
+ The lazy list is based on an optimistic locking scheme for inserts and removes,
+ eliminating the need to use the equivalent of an atomically markable
+ reference. It also has a novel wait-free membership \p find operation
+ that does not need to perform cleanup operations and is more efficient.
+
+ 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 lazy_list::node).
+ - \p T - type to be stored in the list. The type must be based on lazy_list::node (for lazy_list::base_hook)
+ or it must have a member of type lazy_list::node (for lazy_list::member_hook).
+ - \p Traits - type traits. See lazy_list::traits for explanation.
+ It is possible to declare option-based list with cds::intrusive::lazy_list::make_traits metafunction instead of \p Traits template
+ argument. For example, the following traits-based declaration of \p gc::HP lazy list
+ \code
+ #include <cds/intrusive/lazy_list_hp.h>
+ // Declare item stored in your list
+ struct item: public cds::intrusive::lazy_list::node< cds::gc::HP >
+ { ... };
+
+ // Declare comparator for the item
+ struct my_compare { ... }
+
+ // Declare traits
+ struct my_traits: public cds::intrusive::lazy_list::traits
+ {
+ typedef cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::HP > > hook;
+ typedef my_compare compare;
+ };
+
+ // Declare traits-based list
+ typedef cds::intrusive::LazyList< cds::gc::HP, item, my_traits > traits_based_list;
+ \endcode
+ is equivalent for the following option-based list
+ \code
+ #include <cds/intrusive/lazy_list_hp.h>
+
+ // item struct and my_compare are the same
+
+ // Declare option-based list
+ typedef cds::intrusive::LazyList< cds::gc::HP, item,
+ typename cds::intrusive::lazy_list::make_traits<
+ cds::intrusive::opt::hook< cds::intrusive::lazy_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 used.
+ You should select GC needed and include appropriate .h-file:
+ - for gc::HP: \code #include <cds/intrusive/lazy_list_hp.h> \endcode
+ - for gc::DHP: \code #include <cds/intrusive/lazy_list_dhp.h> \endcode
+ - for gc::nogc: \code #include <cds/intrusive/lazy_list_nogc.h> \endcode
+ - for \ref cds_urcu_type "RCU" - see \ref cds_intrusive_LazyList_rcu "LazyList RCU specialization"
+
+ Then, you should incorporate lazy_list::node into your struct \p T and provide
+ appropriate \p lazy_list::traits::hook in your \p Traits template parameters. Usually, for \p Traits
+ a struct based on \p lazy_list::traits should be defined.
+
+ Example for gc::DHP and base hook:
+ \code
+ // Include GC-related lazy list specialization
+ #include <cds/intrusive/lazy_list_dhp.h>
+
+ // Data stored in lazy list
+ struct my_data: public cds::intrusive::lazy_list::node< cds::gc::DHP >
+ {
+ // key field
+ std::string strKey;
+
+ // other data
+ // ...
+ };
+
+ // my_data comparing functor
+ struct compare {
+ 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::lazy_list::traits
+ {
+ typedef cds::intrusive::lazy_list::base_hook< cds::opt::gc< cds::gc::DHP > > hook;
+ typedef my_data_cmp compare;
+ };
+
+ // Declare list type
+ typedef cds::intrusive::LazyList< cds::gc::DHP, my_data, my_traits > traits_based_list;
+ \endcode
+
+ Equivalent option-based code:
+ \code
+ // GC-related specialization
+ #include <cds/intrusive/lazy_list_dhp.h>
+
+ struct my_data {
+ // see above
+ };
+ struct compare {
+ // see above
+ };
+
+ // Declare option-based list
+ typedef cds::intrusive::LazyList< cds::gc::DHP
+ ,my_data
+ , typename cds::intrusive::lazy_list::make_traits<
+ cds::intrusive::opt::hook< cds::intrusive::lazy_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 = lazy_list::traits
+#else
+ ,class Traits
+#endif
+ >
+ class LazyList
+ {
+ public:
+ typedef GC gc; ///< Garbage collector
+ 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
+ typedef typename get_node_traits< value_type, node_type, hook>::type node_traits; ///< node traits
+ typedef typename lazy_list::get_link_checker< node_type, traits::link_checker >::type link_checker; ///< link checker
+
+ 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; ///< C++ memory ordering (see \p lazy_list::traits::memory_model)
+ typedef typename traits::stat stat; ///< Internal statistics
+
+ static_assert((std::is_same< gc, typename node_type::gc >::value), "GC and node_type::gc must be the same type");
+
+ 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 LazyList<
+ gc
+ , value_type
+ , typename cds::opt::make_options< traits, Options...>::type
+ > type;
+ };
+
+ // Stat selector
+ template <typename Stat>
+ using select_stat_wrapper = lazy_list::select_stat_wrapper< Stat >;
+ //@endcond
+
+ protected:
+ typedef typename node_type::marked_ptr marked_node_ptr; ///< Node marked pointer
+ typedef node_type * auxiliary_head; ///< Auxiliary head type (for split-list support)
+
+ protected:
+ //@cond
+ node_type m_Head;
+ node_type m_Tail;
+
+ item_counter m_ItemCounter;
+ stat m_Stat; ///< Internal statistics
+
+ struct clean_disposer {
+ void operator()( value_type * p )
+ {
+ lazy_list::node_cleaner<gc, node_type, memory_model>()( node_traits::to_node_ptr( p ));
+ disposer()( p );
+ }
+ };
+
+ /// Position pointer for item search
+ struct position {
+ node_type * pPred; ///< Previous node
+ node_type * pCur; ///< Current node
+
+ typename gc::template GuardArray<2> guards; ///< Guards array
+
+ enum {
+ guard_prev_item,
+ guard_current_item
+ };
+
+ /// Locks nodes \p pPred and \p pCur
+ void lock()
+ {
+ pPred->m_Lock.lock();
+ pCur->m_Lock.lock();
+ }
+
+ /// Unlocks nodes \p pPred and \p pCur
+ void unlock()
+ {
+ pCur->m_Lock.unlock();
+ pPred->m_Lock.unlock();
+ }
+ };
+
+ typedef std::unique_lock< position > scoped_position_lock;
+ //@endcond
+
+ protected:
+ //@cond
+ void link_node( node_type * pNode, node_type * pPred, node_type * pCur )
+ {
+ assert( pPred->m_pNext.load(memory_model::memory_order_relaxed).ptr() == pCur );
+ link_checker::is_empty( pNode );
+
+ pNode->m_pNext.store( marked_node_ptr(pCur), memory_model::memory_order_release );
+ pPred->m_pNext.store( marked_node_ptr(pNode), memory_model::memory_order_release );
+ }
+
+ void unlink_node( node_type * pPred, node_type * pCur, node_type * pHead )
+ {
+ assert( pPred->m_pNext.load(memory_model::memory_order_relaxed).ptr() == pCur );
+
+ node_type * pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr();
+ pCur->m_pNext.store( marked_node_ptr( pHead, 1 ), memory_model::memory_order_release ); // logical removal + back-link for search
+ pPred->m_pNext.store( marked_node_ptr( pNext ), memory_model::memory_order_release); // physically deleting
+ }
+
+ void retire_node( node_type * pNode )
+ {
+ assert( pNode != nullptr );
+ gc::template retire<clean_disposer>( node_traits::to_value_ptr( *pNode ));
+ }
+ //@endcond
+
+ protected:
+ //@cond
+ template <bool IsConst>
+ class iterator_type
+ {
+ friend class LazyList;
+
+ protected:
+ value_type * m_pNode;
+ typename gc::Guard m_Guard;
+
+ void next()
+ {
+ assert( m_pNode != nullptr );
+
+ if ( m_pNode ) {
+ typename gc::Guard g;
+ node_type * pCur = node_traits::to_node_ptr( m_pNode );
+ if ( pCur->m_pNext.load( memory_model::memory_order_relaxed ).ptr() != nullptr ) { // if pCur is not tail node
+ node_type * pNext;
+ do {
+ pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr();
+ g.assign( node_traits::to_value_ptr( pNext ));
+ } while ( pNext != pCur->m_pNext.load(memory_model::memory_order_relaxed).ptr());
+
+ m_pNode = m_Guard.assign( g.template get<value_type>());
+ }
+ }
+ }
+
+ void skip_deleted()
+ {
+ if ( m_pNode != nullptr ) {
+ typename gc::Guard g;
+ node_type * pNode = node_traits::to_node_ptr( m_pNode );
+
+ // Dummy tail node could not be marked
+ while ( pNode->is_marked()) {
+ node_type * p = pNode->m_pNext.load(memory_model::memory_order_relaxed).ptr();
+ g.assign( node_traits::to_value_ptr( p ));
+ if ( p == pNode->m_pNext.load(memory_model::memory_order_relaxed).ptr())
+ pNode = p;
+ }
+ if ( pNode != node_traits::to_node_ptr( m_pNode ))
+ m_pNode = m_Guard.assign( g.template get<value_type>());
+ }
+ }
+
+ iterator_type( node_type * pNode )
+ {
+ m_pNode = m_Guard.assign( node_traits::to_value_ptr( pNode ));
+ skip_deleted();
+ }
+
+ 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();
+ skip_deleted();
+ return *this;
+ }
+
+ iterator_type& operator = (iterator_type const& src)
+ {
+ m_pNode = src.m_pNode;
+ m_Guard.assign( m_pNode );
+ return *this;
+ }
+
+ 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 lazy 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 (\p gc::HP), a guard is limited resource per thread, so an exception (or assertion) "no free guard"
+ may be thrown if a limit of guard count per thread is exceeded.
+ - The iterator cannot be moved across thread boundary since it contains GC's guard that is thread-private GC data.
+ - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
+ deleting operations it 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.
+ */
+ 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()
+ {
+ iterator it( &m_Head );
+ ++it ; // skip dummy head
+ return it;
+ }
+
+ /// 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.
+
+ The returned value can be used only to control reaching the end of the list.
+ For empty list \code begin() == end() \endcode
+ */
+ iterator end()
+ {
+ return iterator( &m_Tail );
+ }
+
+ /// Returns a forward const iterator addressing the first element in a list
+ const_iterator begin() const
+ {
+ return get_const_begin();
+ }
+
+ /// Returns a forward const iterator addressing the first element in a list
+ const_iterator cbegin() const
+ {
+ return get_const_begin();
+ }
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a list
+ const_iterator end() const
+ {
+ return get_const_end();
+ }
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a list
+ const_iterator cend() const
+ {
+ return get_const_end();
+ }
+ //@}
+
+ private:
+ //@cond
+ const_iterator get_const_begin() const
+ {
+ const_iterator it( const_cast<node_type *>( &m_Head ));
+ ++it ; // skip dummy head
+ return it;
+ }
+ const_iterator get_const_end() const
+ {
+ return const_iterator( const_cast<node_type *>(&m_Tail));
+ }
+ //@endcond
+
+ public:
+ /// Default constructor initializes empty list
+ LazyList()
+ {
+ m_Head.m_pNext.store( marked_node_ptr( &m_Tail ), memory_model::memory_order_relaxed );
+ }
+
+ //@cond
+ template <typename Stat, typename = std::enable_if<std::is_same<stat, lazy_list::wrapped_stat<Stat>>::value >>
+ explicit LazyList( Stat& st )
+ : m_Stat( st )
+ {
+ m_Head.m_pNext.store( marked_node_ptr( &m_Tail ), memory_model::memory_order_relaxed );
+ }
+ //@endcond
+
+ /// Destroys the list object
+ ~LazyList()
+ {
+ clear();
+ assert( m_Head.m_pNext.load( memory_model::memory_order_relaxed ).ptr() == &m_Tail );
+ m_Head.m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ }
+
+ /// Inserts new node
+ /**
+ The function inserts \p val in the list if the list does not contain
+ an item with key equal to \p val.
+
+ Returns \p true if \p val is linked into the list, \p false otherwise.
+ */
+ bool insert( value_type& val )
+ {
+ return insert_at( &m_Head, 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.
+ While the functor \p f is called the item \p val is locked so
+ the functor has an exclusive access to the item.
+ The user-defined functor is called only if the inserting is success.
+ */
+ template <typename Func>
+ bool insert( value_type& val, Func f )
+ {
+ return insert_at( &m_Head, val, f );
+ }
+
+ /// Updates the item
+ /**
+ The operation performs inserting or changing data with lock-free manner.
+
+ If the item \p val not found in the list, then \p val is inserted into the list
+ iff \p bAllowInsert is \p true.
+ Otherwise, the functor \p func is called with item found.
+ The functor signature is:
+ \code
+ struct functor {
+ void operator()( 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
+ refer to the same thing.
+
+ The functor may change non-key fields of the \p item.
+ While the functor \p f is working the item \p item is locked,
+ so \p func has exclusive access to the item.
+
+ Returns <tt> std::pair<bool, bool> </tt> 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 \p key
+ already is in the list.
+
+ The function makes RCU lock internally.
+ */
+ template <typename Func>
+ std::pair<bool, bool> update( value_type& val, Func func, bool bAllowInsert = true )
+ {
+ return update_at( &m_Head, val, func, bAllowInsert );
+ }
+ //@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 unlink it from the list
+ if it is found and it is equal to \p val.
+
+ Difference between \ref erase and \p unlink functions: \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 that list, i.e. the pointer to item found
+ is equal to <tt> &val </tt>.
+
+ The function returns \p true if success and \p false otherwise.
+
+ \p disposer specified in \p Traits is called for unlinked item.
+ */
+ bool unlink( value_type& val )
+ {
+ return unlink_at( &m_Head, val );
+ }
+
+ /// Deletes the item from the list
+ /** \anchor cds_intrusive_LazyList_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 the item with the key equal to \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_Head, key, key_comparator());
+ }
+
+ /// Deletes the item from the list using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_intrusive_LazyList_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_Head, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+
+ /// Deletes the item from the list
+ /** \anchor cds_intrusive_LazyList_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 disposer specified in \p Traits is called for deleted item.
+ */
+ template <typename Q, typename Func>
+ bool erase( const Q& key, Func func )
+ {
+ return erase_at( &m_Head, 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_LazyList_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( const Q& key, Less pred, Func func )
+ {
+ CDS_UNUSED( pred );
+ return erase_at( &m_Head, key, cds::opt::details::make_comparator_from_less<Less>(), func );
+ }
+
+ /// Extracts the item from the list with specified \p key
+ /** \anchor cds_intrusive_LazyList_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 the function 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 specified in class' template parameters when returned \p 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::LazyList< cds::gc::HP, foo, my_traits > ord_list;
+ ord_list theList;
+ // ...
+ {
+ ord_list::guarded_ptr gp( theList.extract( 5 ));
+ // Deal with gp
+ // ...
+
+ // Destructor of gp releases internal HP guard
+ }
+ \endcode
+ */
+ template <typename Q>
+ guarded_ptr extract( Q const& key )
+ {
+ return extract_at( &m_Head, key, key_comparator());
+ }
+
+ /// Extracts the item from the list with comparing functor \p pred
+ /**
+ The function is an analog of \ref cds_intrusive_LazyList_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_Head, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+
+ /// Finds the key \p key
+ /** \anchor cds_intrusive_LazyList_hp_find
+ 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.
+ While the functor \p f is calling the item \p item is locked.
+
+ The function returns \p true if \p key is found, \p false otherwise.
+ */
+ template <typename Q, typename Func>
+ bool find( Q& key, Func f )
+ {
+ return find_at( &m_Head, key, key_comparator(), f );
+ }
+ //@cond
+ template <typename Q, typename Func>
+ bool find( Q const& key, Func f )
+ {
+ return find_at( &m_Head, key, key_comparator(), f );
+ }
+ //@endcond
+
+ /// Finds the key \p key using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_intrusive_LazyList_hp_find "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_Head, 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_Head, 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_Head, key, key_comparator());
+ }
+ //@cond
+ template <typename Q>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( Q const& key )
+ {
+ return contains( key );
+ }
+ //@cond
+
+ /// Checks whether the map 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_Head, 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 \p key and return the item found
+ /** \anchor cds_intrusive_LazyList_hp_get
+ The function searches the item with key equal to \p key
+ and returns an guarded pointer to it.
+ 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 \p 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::LazyList< 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 class \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_Head, key, key_comparator());
+ }
+
+ /// Finds \p key and return the item found
+ /**
+ The function is an analog of \ref cds_intrusive_LazyList_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_Head, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+
+ /// Clears the list
+ void clear()
+ {
+ typename gc::Guard guard;
+ marked_node_ptr h;
+ while ( !empty()) {
+ h = m_Head.m_pNext.load( memory_model::memory_order_relaxed );
+ guard.assign( node_traits::to_value_ptr( h.ptr()));
+ if ( m_Head.m_pNext.load(memory_model::memory_order_acquire) == h ) {
+ m_Head.m_Lock.lock();
+ h->m_Lock.lock();
+
+ unlink_node( &m_Head, h.ptr(), &m_Head );
+ --m_ItemCounter;
+
+ h->m_Lock.unlock();
+ m_Head.m_Lock.unlock();
+
+ retire_node( h.ptr()) ; // free node
+ }
+ }
+ }
+
+ /// Checks if the list is empty
+ bool empty() const
+ {
+ return m_Head.m_pNext.load( memory_model::memory_order_relaxed ).ptr() == &m_Tail;
+ }
+
+ /// 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_Head, pNode );
+ }
+
+ // split-list support
+ bool insert_aux_node( node_type * pHead, node_type * pNode )
+ {
+ assert( pNode != nullptr );
+
+ // Hack: convert node_type to value_type.
+ // In principle, auxiliary node cannot be reducible to value_type
+ // We assume that internal comparator can correctly distinguish aux and regular node.
+ return insert_at( pHead, *node_traits::to_value_ptr( pNode ));
+ }
+
+ bool insert_at( node_type * pHead, value_type& val )
+ {
+ position pos;
+ key_comparator cmp;
+
+ while ( true ) {
+ search( pHead, val, pos, key_comparator());
+ {
+ scoped_position_lock alp( pos );
+ if ( validate( pos.pPred, pos.pCur )) {
+ if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
+ // failed: key already in list
+ m_Stat.onInsertFailed();
+ return false;
+ }
+ else {
+ link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
+ break;
+ }
+ }
+ }
+
+ m_Stat.onInsertRetry();
+ }
+
+ ++m_ItemCounter;
+ m_Stat.onInsertSuccess();
+ return true;
+ }
+
+ template <typename Func>
+ bool insert_at( node_type * pHead, value_type& val, Func f )
+ {
+ position pos;
+ key_comparator cmp;
+
+ while ( true ) {
+ search( pHead, val, pos, key_comparator());
+ {
+ scoped_position_lock alp( pos );
+ if ( validate( pos.pPred, pos.pCur )) {
+ if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
+ // failed: key already in list
+ m_Stat.onInsertFailed();
+ return false;
+ }
+ else {
+ link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
+ f( val );
+ break;
+ }
+ }
+ }
+
+ m_Stat.onInsertRetry();
+ }
+
+ ++m_ItemCounter;
+ m_Stat.onInsertSuccess();
+ return true;
+ }
+
+ template <typename Func>
+ std::pair<bool, bool> update_at( node_type * pHead, value_type& val, Func func, bool bAllowInsert )
+ {
+ position pos;
+ key_comparator cmp;
+
+ while ( true ) {
+ search( pHead, val, pos, key_comparator());
+ {
+ scoped_position_lock alp( pos );
+ if ( validate( pos.pPred, pos.pCur )) {
+ if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
+ // key already in the list
+
+ func( false, *node_traits::to_value_ptr( *pos.pCur ) , val );
+ m_Stat.onUpdateExisting();
+ return std::make_pair( true, false );
+ }
+ else {
+ // new key
+ if ( !bAllowInsert ) {
+ m_Stat.onUpdateFailed();
+ return std::make_pair( false, false );
+ }
+
+ link_node( node_traits::to_node_ptr( val ), pos.pPred, pos.pCur );
+ func( true, val, val );
+ break;
+ }
+ }
+ }
+
+ m_Stat.onUpdateRetry();
+ }
+
+ ++m_ItemCounter;
+ m_Stat.onUpdateNew();
+ return std::make_pair( true, true );
+ }
+
+ bool unlink_at( node_type * pHead, value_type& val )
+ {
+ position pos;
+ key_comparator cmp;
+
+ while ( true ) {
+ search( pHead, val, pos, key_comparator());
+ {
+ int nResult = 0;
+ {
+ scoped_position_lock alp( pos );
+ if ( validate( pos.pPred, pos.pCur )) {
+ if ( pos.pCur != &m_Tail
+ && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0
+ && node_traits::to_value_ptr( pos.pCur ) == &val )
+ {
+ // item found
+ unlink_node( pos.pPred, pos.pCur, pHead );
+ nResult = 1;
+ }
+ else
+ nResult = -1;
+ }
+ }
+
+ if ( nResult ) {
+ if ( nResult > 0 ) {
+ --m_ItemCounter;
+ retire_node( pos.pCur );
+ m_Stat.onEraseSuccess();
+ return true;
+ }
+
+ m_Stat.onEraseFailed();
+ return false;
+ }
+ }
+
+ m_Stat.onEraseRetry();
+ }
+ }
+
+ template <typename Q, typename Compare, typename Func>
+ bool erase_at( node_type * pHead, const Q& val, Compare cmp, Func f, position& pos )
+ {
+ while ( true ) {
+ search( pHead, val, pos, cmp );
+ {
+ int nResult = 0;
+ {
+ scoped_position_lock alp( pos );
+ if ( validate( pos.pPred, pos.pCur )) {
+ if ( pos.pCur != &m_Tail && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
+ // key found
+ unlink_node( pos.pPred, pos.pCur, pHead );
+ f( *node_traits::to_value_ptr( *pos.pCur ));
+ nResult = 1;
+ }
+ else {
+ nResult = -1;
+ }
+ }
+ }
+ if ( nResult ) {
+ if ( nResult > 0 ) {
+ --m_ItemCounter;
+ retire_node( pos.pCur );
+ m_Stat.onEraseSuccess();
+ return true;
+ }
+
+ m_Stat.onEraseFailed();
+ return false;
+ }
+ }
+
+ m_Stat.onEraseRetry();
+ }
+ }
+
+ template <typename Q, typename Compare, typename Func>
+ bool erase_at( node_type * pHead, const Q& val, Compare cmp, Func f )
+ {
+ position pos;
+ return erase_at( pHead, val, cmp, f, pos );
+ }
+
+ template <typename Q, typename Compare>
+ bool erase_at( node_type * pHead, const Q& val, Compare cmp )
+ {
+ position pos;
+ return erase_at( pHead, val, cmp, [](value_type const &){}, pos );
+ }
+
+ template <typename Q, typename Compare>
+ guarded_ptr extract_at( node_type * pHead, const Q& val, Compare cmp )
+ {
+ position pos;
+ if ( erase_at( pHead, val, cmp, [](value_type const &){}, pos ))
+ return guarded_ptr( pos.guards.release( position::guard_current_item ));
+ return guarded_ptr();
+ }
+
+ template <typename Q, typename Compare, typename Func>
+ bool find_at( node_type * pHead, Q& val, Compare cmp, Func f )
+ {
+ position pos;
+
+ search( pHead, val, pos, cmp );
+ if ( pos.pCur != &m_Tail ) {
+ std::unique_lock< typename node_type::lock_type> al( pos.pCur->m_Lock );
+ if ( !pos.pCur->is_marked()
+ && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 )
+ {
+ f( *node_traits::to_value_ptr( *pos.pCur ), val );
+ m_Stat.onFindSuccess();
+ return true;
+ }
+ }
+
+ m_Stat.onFindFailed();
+ return false;
+ }
+
+ template <typename Q, typename Compare>
+ bool find_at( node_type * pHead, Q const& val, Compare cmp )
+ {
+ position pos;
+
+ search( pHead, val, pos, cmp );
+ if ( pos.pCur != &m_Tail && !pos.pCur->is_marked() && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 ) {
+ m_Stat.onFindSuccess();
+ return true;
+ }
+
+ m_Stat.onFindFailed();
+ return false;
+ }
+
+ template <typename Q, typename Compare>
+ guarded_ptr get_at( node_type * pHead, Q const& val, Compare cmp )
+ {
+ position pos;
+
+ search( pHead, val, pos, cmp );
+ if ( pos.pCur != &m_Tail
+ && !pos.pCur->is_marked()
+ && cmp( *node_traits::to_value_ptr( *pos.pCur ), val ) == 0 )
+ {
+ 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>
+ void search( node_type * pHead, const Q& key, position& pos, Compare cmp )
+ {
+ node_type const* pTail = &m_Tail;
+
+ marked_node_ptr pCur( pHead );
+ marked_node_ptr pPrev( pHead );
+
+ while ( pCur.ptr() != pTail ) {
+ if ( pCur.ptr() != pHead ) {
+ if ( cmp( *node_traits::to_value_ptr( *pCur.ptr()), key ) >= 0 )
+ break;
+ }
+
+ pos.guards.copy( position::guard_prev_item, position::guard_current_item );
+ pPrev = pCur;
+
+ pCur = pos.guards.protect( position::guard_current_item, pPrev->m_pNext,
+ []( marked_node_ptr p ) { return node_traits::to_value_ptr( p.ptr()); }
+ );
+ assert( pCur.ptr() != nullptr );
+ if ( pCur.bits())
+ pPrev = pCur = pHead;
+ }
+
+ pos.pCur = pCur.ptr();
+ pos.pPred = pPrev.ptr();
+ }
+
+ bool validate( node_type * pPred, node_type * pCur ) noexcept
+ {
+ if ( validate_link( pPred, pCur )) {
+ m_Stat.onValidationSuccess();
+ return true;
+ }
+
+ m_Stat.onValidationFailed();
+ return false;
+ }
+
+ static bool validate_link( node_type * pPred, node_type * pCur ) noexcept
+ {
+ return !pPred->is_marked()
+ && !pCur->is_marked()
+ && pPred->m_pNext.load(memory_model::memory_order_relaxed) == pCur;
+ }
+
+ //@endcond
+ };
+}} // namespace cds::intrusive
+
+#endif // CDSLIB_INTRUSIVE_IMPL_LAZY_LIST_H
projects / c11concurrency-benchmarks.git / blobdiff