-//$$CDS-header$$
+/*
+ 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_CONTAINER_MICHAEL_SET_RCU_H
#define CDSLIB_CONTAINER_MICHAEL_SET_RCU_H
{
public:
typedef cds::urcu::gc< RCU > gc; ///< RCU used as garbage collector
- typedef OrderedList bucket_type; ///< type of ordered list to be used as a bucket implementation
+ typedef OrderedList ordered_list; ///< type of ordered list to be used as a bucket implementation
typedef Traits traits; ///< Set traits
- typedef typename bucket_type::value_type value_type; ///< type of value to be stored in the list
- typedef typename bucket_type::key_comparator key_comparator; ///< key comparing functor
+ typedef typename ordered_list::value_type value_type; ///< type of value to be stored in the list
+ typedef typename ordered_list::key_comparator key_comparator; ///< key comparing functor
+#ifdef CDS_DOXYGEN_INVOKED
+ typedef typename ordered_list::stat stat; ///< Internal statistics
+ typedef typename ordered_list::exempt_ptr exempt_ptr; ///< pointer to extracted node
+ typedef typename ordered_list::raw_ptr raw_ptr; ///< Return type of \p get() member function and its derivatives
+#endif
/// Hash functor for \ref value_type and all its derivatives that you use
typedef typename cds::opt::v::hash_selector< typename traits::hash >::type hash;
- typedef typename traits::item_counter item_counter; ///< Item counter type
+ typedef typename traits::item_counter item_counter; ///< Item counter type
+ typedef typename traits::allocator allocator; ///< Bucket table allocator
- /// Bucket table allocator
- typedef cds::details::Allocator< bucket_type, typename traits::allocator > bucket_table_allocator;
-
- typedef typename bucket_type::rcu_lock rcu_lock; ///< RCU scoped lock
- typedef typename bucket_type::exempt_ptr exempt_ptr; ///< pointer to extracted node
- typedef typename bucket_type::raw_ptr raw_ptr; ///< Return type of \p get() member function and its derivatives
+ typedef typename ordered_list::rcu_lock rcu_lock; ///< RCU scoped lock
/// Group of \p extract_xxx functions require external locking if underlying ordered list requires that
- static CDS_CONSTEXPR const bool c_bExtractLockExternal = bucket_type::c_bExtractLockExternal;
+ static CDS_CONSTEXPR const bool c_bExtractLockExternal = ordered_list::c_bExtractLockExternal;
- //@cond
- typedef cds::container::michael_set::implementation_tag implementation_tag;
- //@endcond
+ // GC and OrderedList::gc must be the same
+ static_assert(std::is_same<gc, typename ordered_list::gc>::value, "GC and OrderedList::gc must be the same");
- protected:
- item_counter m_ItemCounter; ///< Item counter
- hash m_HashFunctor; ///< Hash functor
- bucket_type * m_Buckets; ///< bucket table
-
- private:
//@cond
- const size_t m_nHashBitmask;
+ typedef typename ordered_list::template select_stat_wrapper< typename ordered_list::stat > bucket_stat;
+
+ typedef typename ordered_list::template rebind_traits<
+ cds::opt::item_counter< cds::atomicity::empty_item_counter >
+ , cds::opt::stat< typename bucket_stat::wrapped_stat >
+ >::type internal_bucket_type_;
+
+ class internal_bucket_type: public internal_bucket_type_
+ {
+ typedef internal_bucket_type_ base_class;
+ public:
+ using base_class::base_class;
+ using typename base_class::node_type;
+ using base_class::alloc_node;
+ using base_class::insert_node;
+ using base_class::node_to_value;
+ };
+
+ typedef typename internal_bucket_type::exempt_ptr exempt_ptr;
+ typedef typename internal_bucket_type::raw_ptr raw_ptr;
+ typedef typename bucket_stat::stat stat;
//@endcond
protected:
//@cond
- /// Calculates hash value of \p key
- template <typename Q>
- size_t hash_value( Q const& key ) const
- {
- return m_HashFunctor( key ) & m_nHashBitmask;
- }
+ /// Bucket table allocator
+ typedef typename allocator::template rebind< internal_bucket_type >::other bucket_table_allocator;
- /// Returns the bucket (ordered list) for \p key
- template <typename Q>
- bucket_type& bucket( Q const& key )
- {
- return m_Buckets[ hash_value( key ) ];
- }
- template <typename Q>
- bucket_type const& bucket( Q const& key ) const
- {
- return m_Buckets[ hash_value( key ) ];
- }
+ const size_t m_nHashBitmask;
+ hash m_HashFunctor; ///< Hash functor
+ internal_bucket_type* m_Buckets; ///< bucket table
+ item_counter m_ItemCounter; ///< Item counter
+ stat m_Stat; ///< Internal statistics
//@endcond
+
public:
+ ///@name Forward iterators (thread-safe under RCU lock)
+ //@{
/// Forward iterator
/**
The forward iterator for Michael's set is based on \p OrderedList forward iterator and has some features:
- it has no post-increment operator
- it iterates items in unordered fashion
- - The iterator cannot be moved across thread boundary since it may contain 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 set.
- Therefore, the use of iterators in concurrent environment is not good idea. Use the iterator for the concurrent container
- for debug purpose only.
+ You may safely use iterators in multi-threaded environment only under RCU lock.
+ Otherwise, a crash is possible if another thread deletes the element the iterator points to.
+
+ 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 michael_set::details::iterator< bucket_type, false > iterator;
+ typedef michael_set::details::iterator< internal_bucket_type, false > iterator;
/// Const forward iterator
- typedef michael_set::details::iterator< bucket_type, true > const_iterator;
+ typedef michael_set::details::iterator< internal_bucket_type, true > const_iterator;
/// Returns a forward iterator addressing the first element in a set
/**
*/
iterator begin()
{
- return iterator( m_Buckets[0].begin(), m_Buckets, m_Buckets + bucket_count() );
+ return iterator( m_Buckets[0].begin(), m_Buckets, m_Buckets + bucket_count());
}
/// Returns an iterator that addresses the location succeeding the last element in a set
*/
iterator end()
{
- return iterator( m_Buckets[bucket_count() - 1].end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() );
+ return iterator( m_Buckets[bucket_count() - 1].end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count());
}
/// Returns a forward const iterator addressing the first element in a set
- //@{
const_iterator begin() const
{
return get_const_begin();
}
+
+ /// Returns a forward const iterator addressing the first element in a set
const_iterator cbegin() const
{
return get_const_begin();
}
- //@}
/// Returns an const iterator that addresses the location succeeding the last element in a set
- //@{
const_iterator end() const
{
return get_const_end();
}
+
+ /// Returns an const iterator that addresses the location succeeding the last element in a set
const_iterator cend() const
{
return get_const_end();
}
- //@}
-
- private:
- //@cond
- const_iterator get_const_begin() const
- {
- return const_iterator( const_cast<bucket_type const&>(m_Buckets[0]).begin(), m_Buckets, m_Buckets + bucket_count() );
- }
- const_iterator get_const_end() const
- {
- return const_iterator( const_cast<bucket_type const&>(m_Buckets[bucket_count() - 1]).end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() );
- }
- //@endcond
+ //@}
public:
/// Initialize hash set
size_t nMaxItemCount, ///< estimation of max item count in the hash set
size_t nLoadFactor ///< load factor: estimation of max number of items in the bucket
) : m_nHashBitmask( michael_set::details::init_hash_bitmask( nMaxItemCount, nLoadFactor ))
+ , m_Buckets( bucket_table_allocator().allocate( bucket_count()))
{
- // GC and OrderedList::gc must be the same
- static_assert( std::is_same<gc, typename bucket_type::gc>::value, "GC and OrderedList::gc must be the same");
-
- // atomicity::empty_item_counter is not allowed as a item counter
- static_assert( !std::is_same<item_counter, atomicity::empty_item_counter>::value,
- "atomicity::empty_item_counter is not allowed as a item counter");
-
- m_Buckets = bucket_table_allocator().NewArray( bucket_count() );
+ for ( auto it = m_Buckets, itEnd = m_Buckets + bucket_count(); it != itEnd; ++it )
+ construct_bucket<bucket_stat>( it );
}
/// Clears hash set and destroys it
~MichaelHashSet()
{
clear();
- bucket_table_allocator().Delete( m_Buckets, bucket_count() );
+
+ for ( auto it = m_Buckets, itEnd = m_Buckets + bucket_count(); it != itEnd; ++it )
+ it->~internal_bucket_type();
+ bucket_table_allocator().deallocate( m_Buckets, bucket_count());
+
}
/// Inserts new node
Returns \p true if \p val is inserted into the set, \p false otherwise.
*/
template <typename Q>
- bool insert( Q const& val )
+ bool insert( Q&& val )
{
- const bool bRet = bucket( val ).insert( val );
+ const bool bRet = bucket( val ).insert( std::forward<Q>( val ));
if ( bRet )
++m_ItemCounter;
return bRet;
synchronization.
*/
template <typename Q, typename Func>
- bool insert( Q const& val, Func f )
+ bool insert( Q&& val, Func f )
{
- const bool bRet = bucket( val ).insert( val, f );
+ const bool bRet = bucket( val ).insert( std::forward<Q>( val ), f );
if ( bRet )
++m_ItemCounter;
return bRet;
}
- /// Ensures that the item exists in the set
- /**
- The operation performs inserting or changing data with lock-free manner.
-
- If the \p val key not found in the set, then the new item created from \p val
- is inserted into the set. Otherwise, the functor \p func is called with the item found.
- The functor \p Func signature is:
- \code
- struct my_functor {
- void operator()( bool bNew, value_type& item, const Q& val );
- };
- \endcode
-
- with arguments:
- - \p bNew - \p true if the item has been inserted, \p false otherwise
- - \p item - item of the set
- - \p val - argument \p key passed into the \p ensure function
-
- The functor may change non-key fields of the \p item.
-
- The function applies RCU lock internally.
-
- Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
- \p second is true if new item has been added or \p false if the item with \p key
- already is in the set.
-
- @warning For \ref cds_nonintrusive_MichaelList_rcu "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
- \ref cds_nonintrusive_LazyList_rcu "LazyList" provides exclusive access to inserted item and does not require any node-level
- synchronization.
- */
/// Updates the element
/**
The operation performs inserting or changing data with lock-free manner.
The function applies RCU lock internally.
- Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successfull,
+ 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 set.
synchronization.
*/
template <typename Q, typename Func>
- std::pair<bool, bool> update( const Q& val, Func func, bool bAllowInsert = true )
+ std::pair<bool, bool> update( Q const& val, Func func, bool bAllowInsert = true )
{
std::pair<bool, bool> bRet = bucket( val ).update( val, func, bAllowInsert );
if ( bRet.second )
template <typename... Args>
bool emplace( Args&&... args )
{
- bool bRet = bucket( value_type(std::forward<Args>(args)...) ).emplace( std::forward<Args>(args)... );
+ typename internal_bucket_type::node_type * pNode = internal_bucket_type::alloc_node( std::forward<Args>( args )... );
+ bool bRet = bucket( internal_bucket_type::node_to_value( *pNode )).insert_node( pNode );
if ( bRet )
++m_ItemCounter;
return bRet;
If the item with the key equal to \p key is not found the function return an empty \p exempt_ptr.
The function just excludes the item from the set and returns a pointer to item found.
- Depends on \p bucket_type you should or should not lock RCU before calling of this function:
+ Depends on \p ordered_list you should or should not lock RCU before calling of this function:
- for the set based on \ref cds_nonintrusive_MichaelList_rcu "MichaelList" RCU should not be locked
- for the set based on \ref cds_nonintrusive_LazyList_rcu "LazyList" RCU should be locked
See ordered list implementation for details.
//@endcond
/// Checks whether the set contains \p key
- /**
+ /**
+
The function searches the item with key equal to \p key
and returns \p true if the key is found, and \p false otherwise.
{
return contains( key, pred );
}
+ //@endcond
/// Finds the key \p key and return the item found
/** \anchor cds_nonintrusive_MichaelHashSet_rcu_get
The function searches the item with key equal to \p key and returns the pointer to item found.
If \p key is not found it returns \p nullptr.
- Note the type of returned value depends on underlying \p bucket_type.
+ Note the type of returned value depends on underlying \p ordered_list.
For details, see documentation of ordered list you use.
Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
/// Checks if the set is empty
/**
- Emptiness is checked by item counting: if item count is zero then the set is empty.
- Thus, the correct item counting feature is an important part of Michael's set implementation.
+ @warning If you use \p atomicity::empty_item_counter in \p traits::item_counter,
+ the function always returns \p true.
*/
bool empty() const
{
}
/// Returns item count in the set
+ /**
+ @warning If you use \p atomicity::empty_item_counter in \p traits::item_counter,
+ the function always returns 0.
+ */
size_t size() const
{
return m_ItemCounter;
}
+ /// Returns const reference to internal statistics
+ stat const& statistics() const
+ {
+ return m_Stat;
+ }
+
/// Returns the size of hash table
/**
Since \p %MichaelHashSet cannot dynamically extend the hash table size,
{
return m_nHashBitmask + 1;
}
+
+ protected:
+ //@cond
+ /// Calculates hash value of \p key
+ template <typename Q>
+ size_t hash_value( Q const& key ) const
+ {
+ return m_HashFunctor( key ) & m_nHashBitmask;
+ }
+
+ /// Returns the bucket (ordered list) for \p key
+ template <typename Q>
+ internal_bucket_type& bucket( Q const& key )
+ {
+ return m_Buckets[hash_value( key )];
+ }
+ template <typename Q>
+ internal_bucket_type const& bucket( Q const& key ) const
+ {
+ return m_Buckets[hash_value( key )];
+ }
+
+ template <typename Stat>
+ typename std::enable_if< Stat::empty >::type construct_bucket( internal_bucket_type* bucket )
+ {
+ new (bucket) internal_bucket_type;
+ }
+
+ template <typename Stat>
+ typename std::enable_if< !Stat::empty >::type construct_bucket( internal_bucket_type* bucket )
+ {
+ new (bucket) internal_bucket_type( m_Stat );
+ }
+
+ const_iterator get_const_begin() const
+ {
+ return const_iterator( const_cast<internal_bucket_type const&>(m_Buckets[0]).begin(), m_Buckets, m_Buckets + bucket_count());
+ }
+ const_iterator get_const_end() const
+ {
+ return const_iterator( const_cast<internal_bucket_type const&>(m_Buckets[bucket_count() - 1]).end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count());
+ }
+ //@endcond
};
}} // namespace cds::container
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