+/*
+ This file is a part of libcds - Concurrent Data Structures library
+
+ (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
+
+ 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_ITERABLE_LIST_H
+#define CDSLIB_INTRUSIVE_IMPL_ITERABLE_LIST_H
+
+#include <cds/intrusive/details/iterable_list_base.h>
+#include <cds/details/make_const_type.h>
+
+namespace cds { namespace intrusive {
+
+ /// Iterable lock-free ordered single-linked list
+ /** @ingroup cds_intrusive_list
+ \anchor cds_intrusive_IterableList_hp
+
+ This lock-free list implementation supports thread-safe iterators.
+ Unlike \p cds::intrusive::MichaelList the iterable list does not require
+ any hook in \p T to be stored in the list.
+
+ 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>.
+
+ Template arguments:
+ - \p GC - Garbage collector used.
+ - \p T - type to be stored in the list.
+ - \p Traits - type traits, default is \p iterable_list::traits. It is possible to declare option-based
+ list with \p cds::intrusive::iterable_list::make_traits metafunction:
+ For example, the following traits-based declaration of \p gc::HP iterable list
+ \code
+ #include <cds/intrusive/iterable_list_hp.h>
+ // Declare item stored in your list
+ struct foo
+ {
+ int nKey;
+ // .... other data
+ };
+
+ // Declare comparator for the item
+ struct my_compare {
+ int operator()( foo const& i1, foo const& i2 ) const
+ {
+ return i1.nKey - i2.nKey;
+ }
+ };
+
+ // Declare traits
+ struct my_traits: public cds::intrusive::iterable_list::traits
+ {
+ typedef my_compare compare;
+ };
+
+ // Declare list
+ typedef cds::intrusive::IterableList< cds::gc::HP, foo, my_traits > list_type;
+ \endcode
+ is equivalent for the following option-based list
+ \code
+ #include <cds/intrusive/iterable_list_hp.h>
+
+ // foo struct and my_compare are the same
+
+ // Declare option-based list
+ typedef cds::intrusive::IterableList< cds::gc::HP, foo,
+ typename cds::intrusive::iterable_list::make_traits<
+ cds::intrusive::opt::compare< my_compare > // item comparator option
+ >::type
+ > option_list_type;
+ \endcode
+
+ \par Usage
+ There are different specializations of this template for each garbage collecting schema.
+ You should select GC you want and include appropriate .h-file:
+ - for \p gc::HP: <tt> <cds/intrusive/iterable_list_hp.h> </tt>
+ - for \p gc::DHP: <tt> <cds/intrusive/iterable_list_dhp.h> </tt>
+ - for \ref cds_urcu_gc "RCU type" - see \ref cds_intrusive_IterableList_rcu "RCU-based IterableList"
+ */
+ template <
+ class GC
+ ,typename T
+#ifdef CDS_DOXYGEN_INVOKED
+ ,class Traits = iterable_list::traits
+#else
+ ,class Traits
+#endif
+ >
+ class IterableList
+ {
+ public:
+ typedef T value_type; ///< type of value stored in the list
+ typedef Traits traits; ///< Traits template parameter
+
+ typedef iterable_list::node< value_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 for \p value_type
+
+ 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 \p cds::opt::memory_model option
+ typedef typename traits::node_allocator node_allocator; ///< Node allocator
+
+ typedef typename gc::template guarded_ptr< value_type > guarded_ptr; ///< Guarded pointer
+
+ static CDS_CONSTEXPR const size_t c_nHazardPtrCount = 2; ///< Count of hazard pointer required for the algorithm
+
+ //@cond
+ // Rebind traits (split-list support)
+ template <typename... Options>
+ struct rebind_traits {
+ typedef IterableList<
+ gc
+ , value_type
+ , typename cds::opt::make_options< traits, Options...>::type
+ > type;
+ };
+ //@endcond
+
+ protected:
+ typedef atomics::atomic< node_type* > atomic_node_ptr; ///< Atomic node 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
+
+ //@cond
+ typedef cds::details::Allocator< node_type, node_allocator > cxx_node_allocator;
+
+ /// Position pointer for item search
+ struct position {
+ atomic_node_ptr * pHead; ///< Previous node (pointer to pPrev->next or to m_pHead)
+ node_type * pPrev; ///< Previous node
+ node_type * pCur; ///< Current node
+
+ value_type * pFound; ///< Value of \p pCur->data, valid only if data found
+ typename gc::Guard guard; ///< guard for \p pFound
+ };
+ //@endcond
+
+ protected:
+ //@cond
+ template <bool IsConst>
+ class iterator_type
+ {
+ friend class IterableList;
+
+ protected:
+ node_type* m_pNode;
+ value_type* m_pVal;
+ typename gc::Guard m_Guard; // for m_pVal
+
+ void next()
+ {
+ while ( m_pNode ) {
+ m_pNode = m_pNode->next.load( memory_model::memory_order_relaxed );
+ if ( !m_pNode )
+ break;
+ m_pVal = m_Guard.protect( m_pNode->data );
+ if ( m_pVal )
+ break;
+ }
+ }
+
+ explicit iterator_type( atomic_node_ptr const& pNode )
+ : m_pNode( pNode.load( memory_model::memory_order_relaxed ))
+ , m_pVal( nullptr )
+ {
+ if ( m_pNode ) {
+ m_pVal = m_Guard.protect( m_pNode->data );
+ if ( !m_pVal )
+ next();
+ }
+ }
+
+ iterator_type( node_type* pNode, value_type* pVal )
+ : m_pNode( pNode )
+ , m_pVal( pVal )
+ {
+ if ( m_pNode ) {
+ assert( pVal != nullptr );
+ m_Guard.assign( pVal );
+ }
+ }
+
+ 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 )
+ , m_pVal( nullptr )
+ {}
+
+ iterator_type( iterator_type const& src )
+ : m_pNode( src.m_pNode )
+ , m_pVal( src.m_pVal )
+ {
+ m_Guard.assign( m_pVal );
+ }
+
+ value_ptr operator ->() const
+ {
+ return m_pVal;
+ }
+
+ value_ref operator *() const
+ {
+ assert( m_pVal != nullptr );
+ return *m_pVal;
+ }
+
+ /// Pre-increment
+ iterator_type& operator ++()
+ {
+ next();
+ return *this;
+ }
+
+ iterator_type& operator = (iterator_type const& src)
+ {
+ m_pNode = src.m_pNode;
+ m_pVal = src.m_pVal;
+ m_Guard.assign( m_pVal );
+ 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 Thread-safe forward iterators
+ //@{
+ /// Forward iterator
+ /**
+ The forward iterator for iterable list has some features:
+ - it has no post-increment operator
+ - to protect the value, the iterator contains a GC-specific guard.
+ 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 is thread-safe: event if the element the iterator points to is removed, the iterator stays valid because
+ it contains the guard keeping the value from to be recycled.
+
+ 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
+
+ @note For two iterators pointed to the same element the value can be different;
+ this code
+ \code
+ if ( it1 == it2 )
+ assert( &(*it1) == &(*it2) );
+ \endcode
+ can throw assertion. The point is that the iterator stores the value of element which can be modified later by other thread.
+ The guard inside the iterator prevents recycling that value so the iterator's value remains valid even after such changing.
+ Other iterator can observe modified value of the element.
+ */
+ 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
+ IterableList()
+ : m_pHead( nullptr )
+ {}
+
+ /// Destroys the list object
+ ~IterableList()
+ {
+ destroy();
+ }
+
+ /// 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 current element is changed to \p val, the element will be retired later
+ by call \p Traits::disposer.
+ The functor \p func is called after inserting or replacing, it signature is:
+ \code
+ void func( value_type& val, value_type * old );
+ \endcode
+ where
+ - \p val - argument \p val passed into the \p %update() function
+ - \p old - old value that will be retired. If new item has been inserted then \p old is \p nullptr.
+
+ Returns std::pair<bool, bool> where \p first is \p true if operation is successful,
+ \p second is \p true if \p val has been added or \p false if the item with that key
+ already in the list.
+ */
+ template <typename Func>
+ std::pair<bool, bool> update( value_type& val, Func func, bool bInsert = true )
+ {
+ return update_at( m_pHead, val, func, bInsert );
+ }
+
+ /// 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 current element is changed to \p val, the element will be retired later
+ by call \p Traits::disposer.
+
+ Returns std::pair<bool, bool> where \p first is \p true if operation is successful,
+ \p second is \p true if \p val has been added or \p false if the item with that key
+ already in the list.
+ */
+ std::pair<bool, bool> update( value_type& val, bool bInsert = true )
+ {
+ return update_at( m_pHead, val, []( value_type&, value_type* ) {}, bINsert );
+ }
+
+ /// 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_IterableList_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_IterableList_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_IterableList_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_IterableList_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_IterableList_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::IterableList< 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 )
+ {
+ guarded_ptr gp;
+ extract_at( m_pHead, gp.guard(), key, key_comparator());
+ return gp;
+ }
+
+ /// Extracts the item using compare functor \p pred
+ /**
+ The function is an analog of \ref cds_intrusive_IterableList_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 );
+ guarded_ptr gp;
+ extract_at( m_pHead, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>());
+ return gp;
+ }
+
+ /// Finds \p key in the list
+ /** \anchor cds_intrusive_IterableList_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 \p %find() 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 function returns \p true if \p val is found, \p false otherwise.
+ */
+ template <typename Q, typename Func>
+ bool find( Q& key, Func f ) const
+ {
+ return find_at( m_pHead, key, key_comparator(), f );
+ }
+ //@cond
+ template <typename Q, typename Func>
+ bool find( Q const& key, Func f ) const
+ {
+ return find_at( m_pHead, key, key_comparator(), f );
+ }
+ //@endcond
+
+ /// Finds \p key in the list and returns iterator pointed to the item found
+ /**
+ If \p key is not found the function returns \p end().
+ */
+ template <typename Q>
+ iterator find( Q& key ) const
+ {
+ return find_iterator_at( m_pHead, key, key_comparator());
+ }
+ //@cond
+ template <typename Q>
+ iterator find( Q const& key ) const
+ {
+ return find_iterator_at( m_pHead, key, key_comparator() );
+ }
+ //@endcond
+
+ /// Finds the \p key using \p pred predicate for searching
+ /**
+ The function is an analog of \ref cds_intrusive_IterableList_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 ) const
+ {
+ 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 ) const
+ {
+ CDS_UNUSED( pred );
+ return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
+ }
+ //@endcond
+
+ /// Finds \p key in the list using \p pred predicate for searching and returns iterator pointed to the item found
+ /**
+ The function is an analog of \p find(Q&) 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.
+
+ If \p key is not found the function returns \p end().
+ */
+ template <typename Q, typename Less>
+ iterator find_with( Q& key, Less pred ) const
+ {
+ CDS_UNUSED( pred );
+ return find_iterator_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+ //@cond
+ template <typename Q, typename Less>
+ iterator find_with( Q const& key, Less pred ) const
+ {
+ CDS_UNUSED( pred );
+ return find_iterator_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+ //@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 ) const
+ {
+ return find_at( m_pHead, key, key_comparator());
+ }
+
+ /// 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 ) const
+ {
+ CDS_UNUSED( pred );
+ return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
+ }
+
+ /// Finds the \p key and return the item found
+ /** \anchor cds_intrusive_IterableList_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::IterableList< 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 ) const
+ {
+ guarded_ptr gp;
+ get_at( m_pHead, gp.guard(), key, key_comparator());
+ return gp;
+ }
+
+ /// Finds the \p key and return the item found
+ /**
+ The function is an analog of \ref cds_intrusive_IterableList_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 ) const
+ {
+ CDS_UNUSED( pred );
+ guarded_ptr gp;
+ get_at( m_pHead, gp.guard(), key, cds::opt::details::make_comparator_from_less<Less>());
+ return gp;
+ }
+
+ /// Clears the list (thread safe, not atomic)
+ void clear()
+ {
+ position pos;
+ for ( pos.pCur = m_pHead.load( memory_model::memory_order_relaxed ); pos.pCur; pos.pCur = pos.pCur->next.load( memory_model::memory_order_relaxed )) {
+ while ( true ) {
+ pos.pFound = pos.guard.protect( pos.pCur->data );
+ if ( !pos.pFound )
+ break;
+ if ( cds_likely( unlink_node( pos ))) {
+ --m_ItemCounter;
+ break;
+ }
+ }
+ }
+ }
+
+ /// Checks if the list is empty
+ /**
+ Emptiness is checked by item counting: if item count is zero then the set is empty.
+ Thus, if you need to use \p %empty() you should provide appropriate (non-empty) \p iterable_list::traits::item_counter
+ feature.
+ */
+ bool empty() const
+ {
+ return size() == 0;
+ }
+
+ /// Returns list's item count
+ /**
+ The value returned depends on item counter provided by \p iterable_list::traits::item_counter. For \p atomicity::empty_item_counter,
+ this function always returns 0.
+ */
+ size_t size() const
+ {
+ return m_ItemCounter.value();
+ }
+
+ protected:
+ //@cond
+#if 0
+ // 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 ) );
+ }
+#endif
+
+ bool insert_at( atomic_node_ptr& refHead, value_type& val )
+ {
+ position pos;
+
+ while ( true ) {
+ if ( search( refHead, val, pos, key_comparator() ) )
+ return false;
+
+ if ( link_node( &val, pos ) ) {
+ ++m_ItemCounter;
+ return true;
+ }
+ }
+ }
+
+ template <typename Func>
+ bool insert_at( atomic_node_ptr& refHead, value_type& val, Func f )
+ {
+ position pos;
+
+ typename gc::Guard guard;
+ guard.assign( &val );
+
+ while ( true ) {
+ if ( search( refHead, val, pos, key_comparator() ) )
+ return false;
+
+ if ( link_node( &val, pos ) ) {
+ f( val );
+ ++m_ItemCounter;
+ return true;
+ }
+ }
+ }
+
+ template <typename Func>
+ std::pair<bool, bool> update_at( atomic_node_ptr& refHead, value_type& val, Func func, bool bInsert )
+ {
+ position pos;
+
+ typename gc::Guard guard;
+ guard.assign( &val );
+
+ while ( true ) {
+ if ( search( refHead, val, pos, key_comparator() ) ) {
+ // try to replace pCur->data with val
+ assert( pos.pFound != nullptr );
+ assert( key_comparator()(*pos.pFound, val) == 0 );
+
+ if ( cds_likely( pos.pCur->data.compare_exchange_strong( pos.pFound, &val, memory_model::memory_order_release, atomics::memory_order_relaxed ))) {
+ if ( pos.pFound != &val ) {
+ retire_data( pos.pFound );
+ func( val, pos.pFound );
+ }
+ return std::make_pair( true, false );
+ }
+ }
+ else {
+ if ( !bInsert )
+ return std::make_pair( false, false );
+
+ if ( link_node( &val, pos ) ) {
+ func( val, static_cast<value_type*>( nullptr ));
+ ++m_ItemCounter;
+ return std::make_pair( true, true );
+ }
+ }
+ }
+ }
+
+ bool unlink_at( atomic_node_ptr& refHead, value_type& val )
+ {
+ position pos;
+
+ back_off bkoff;
+ while ( search( refHead, val, pos, key_comparator())) {
+ if ( pos.pFound == &val ) {
+ if ( unlink_node( pos )) {
+ --m_ItemCounter;
+ return true;
+ }
+ else
+ bkoff();
+ }
+ else
+ break;
+ }
+ 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( *pos.pFound );
+ --m_ItemCounter;
+ return true;
+ }
+ else
+ bkoff();
+ }
+ 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>
+ bool extract_at( atomic_node_ptr& refHead, typename guarded_ptr::native_guard& dest, Q const& val, Compare cmp )
+ {
+ position pos;
+ back_off bkoff;
+ while ( search( refHead, val, pos, cmp )) {
+ if ( unlink_node( pos )) {
+ dest.set( pos.pFound );
+ --m_ItemCounter;
+ return true;
+ }
+ else
+ bkoff();
+ }
+ return false;
+ }
+
+ template <typename Q, typename Compare>
+ bool find_at( atomic_node_ptr const& refHead, Q const& val, Compare cmp ) const
+ {
+ position pos;
+ return search( refHead, val, pos, cmp );
+ }
+
+ template <typename Q, typename Compare, typename Func>
+ bool find_at( atomic_node_ptr const& refHead, Q& val, Compare cmp, Func f ) const
+ {
+ position pos;
+ if ( search( refHead, val, pos, cmp )) {
+ assert( pos.pFound != nullptr );
+ f( *pos.pFound, val );
+ return true;
+ }
+ return false;
+ }
+
+ template <typename Q, typename Compare>
+ iterator find_iterator_at( atomic_node_ptr const& refHead, Q const& val, Compare cmp ) const
+ {
+ position pos;
+ if ( search( refHead, val, pos, cmp )) {
+ assert( pos.pCur != nullptr );
+ assert( pos.pFound != nullptr );
+ return iterator( pos.pCur, pos.pFound );
+ }
+ return iterator{};
+ }
+
+ template <typename Q, typename Compare>
+ bool get_at( atomic_node_ptr const& refHead, typename guarded_ptr::native_guard& guard, Q const& val, Compare cmp ) const
+ {
+ position pos;
+ if ( search( refHead, val, pos, cmp )) {
+ guard.set( pos.pFound );
+ return true;
+ }
+ return false;
+ }
+ //@endcond
+
+ protected:
+
+ //@cond
+ template <typename Q, typename Compare >
+ bool search( atomic_node_ptr const& refHead, const Q& val, position& pos, Compare cmp ) const
+ {
+ atomic_node_ptr* pHead = const_cast<atomic_node_ptr*>( &refHead );
+ node_type * pPrev = nullptr;
+
+ while ( true ) {
+ node_type * pCur = pHead->load( memory_model::memory_order_relaxed );
+
+ if ( pCur == nullptr ) {
+ // end-of-list
+ pos.pHead = pHead;
+ pos.pPrev = pPrev;
+ pos.pCur = nullptr;
+ pos.pFound = nullptr;
+ return false;
+ }
+
+ value_type * pVal = pos.guard.protect( pCur->data );
+
+ if ( pVal ) {
+ int nCmp = cmp( *pVal, val );
+ if ( nCmp >= 0 ) {
+ pos.pHead = pHead;
+ pos.pPrev = pPrev;
+ pos.pCur = pCur;
+ pos.pFound = pVal;
+ return nCmp == 0;
+ }
+ }
+
+ pPrev = pCur;
+ pHead = &( pCur->next );
+ }
+ }
+ //@endcond
+
+ private:
+ //@cond
+ static node_type * alloc_node( value_type * pVal )
+ {
+ return cxx_node_allocator().New( pVal );
+ }
+
+ static void delete_node( node_type * pNode )
+ {
+ cxx_node_allocator().Delete( pNode );
+ }
+
+ static void retire_data( value_type * pVal )
+ {
+ assert( pVal != nullptr );
+ gc::template retire<disposer>( pVal );
+ }
+
+ void destroy()
+ {
+ node_type * pNode = m_pHead.load( memory_model::memory_order_relaxed );
+ while ( pNode ) {
+ value_type * pVal = pNode->data.load( memory_model::memory_order_relaxed );
+ if ( pVal )
+ retire_data( pVal );
+ node_type * pNext = pNode->next.load( memory_model::memory_order_relaxed );
+ delete_node( pNode );
+ pNode = pNext;
+ }
+ }
+
+ static bool link_node( value_type * pVal, position& pos )
+ {
+ if ( pos.pPrev ) {
+ if ( pos.pPrev->data.load( memory_model::memory_order_relaxed ) == nullptr ) {
+ // reuse pPrev
+ value_type * p = nullptr;
+ return pos.pPrev->data.compare_exchange_strong( p, pVal, memory_model::memory_order_release, atomics::memory_order_relaxed );
+ }
+ else {
+ // insert new node between pos.pPrev and pos.pCur
+ node_type * pNode = alloc_node( pVal );
+ pNode->next.store( pos.pCur, memory_model::memory_order_relaxed );
+
+ if ( cds_likely( pos.pPrev->next.compare_exchange_strong( pos.pCur, pNode, memory_model::memory_order_release, atomics::memory_order_relaxed )))
+ return true;
+
+ delete_node( pNode );
+ }
+ }
+ else {
+ node_type * pNode = alloc_node( pVal );
+ pNode->next.store( pos.pCur, memory_model::memory_order_relaxed );
+ if ( cds_likely( pos.pHead->compare_exchange_strong( pos.pCur, pNode, memory_model::memory_order_release, atomics::memory_order_relaxed ) ) )
+ return true;
+
+ delete_node( pNode );
+ }
+ return false;
+ }
+
+ static bool unlink_node( position& pos )
+ {
+ assert( pos.pCur != nullptr );
+ assert( pos.pFound != nullptr );
+
+ if ( pos.pCur->data.compare_exchange_strong( pos.pFound, nullptr, memory_model::memory_order_acquire, atomics::memory_order_relaxed ) ) {
+ retire_data( pos.pFound );
+ return true;
+ }
+ return false;
+ }
+
+ //@endcond
+ };
+}} // namespace cds::intrusive
+
+#endif // #ifndef CDSLIB_INTRUSIVE_IMPL_ITERABLE_LIST_H
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