-//$$CDS-header$$
+/*
+ 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_CONTAINER_MICHAEL_SET_RCU_H
#define CDSLIB_CONTAINER_MICHAEL_SET_RCU_H
typedef typename cds::opt::v::hash_selector< typename traits::hash >::type hash;
typedef typename traits::item_counter item_counter; ///< Item counter type
- /// 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
static CDS_CONSTEXPR const bool c_bExtractLockExternal = bucket_type::c_bExtractLockExternal;
protected:
- item_counter m_ItemCounter; ///< Item counter
- hash m_HashFunctor; ///< Hash functor
- bucket_type * m_Buckets; ///< bucket table
+ //@cond
+ class internal_bucket_type: public bucket_type
+ {
+ typedef bucket_type base_class;
+ public:
+ using base_class::node_type;
+ using base_class::alloc_node;
+ using base_class::insert_node;
+ using base_class::node_to_value;
+ };
+
+ /// Bucket table allocator
+ typedef cds::details::Allocator< internal_bucket_type, typename traits::allocator > bucket_table_allocator;
+
+ //@endcond
+
+ protected:
+ item_counter m_ItemCounter; ///< Item counter
+ hash m_HashFunctor; ///< Hash functor
+ internal_bucket_type * m_Buckets; ///< bucket table
private:
//@cond
/// Returns the bucket (ordered list) for \p key
template <typename Q>
- bucket_type& bucket( Q const& key )
+ internal_bucket_type& bucket( Q const& key )
{
return m_Buckets[ hash_value( key ) ];
}
template <typename Q>
- bucket_type const& bucket( Q const& key ) const
+ internal_bucket_type const& bucket( Q const& key ) const
{
return m_Buckets[ hash_value( key ) ];
}
//@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;
}
/// 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() );
+ 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<bucket_type const&>(m_Buckets[bucket_count() - 1]).end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() );
+ 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
// 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");
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.
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;
//@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
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