-//$$CDS-header$$
-
-#ifndef __CDS_CONTAINER_MICHAEL_SET_RCU_H
-#define __CDS_CONTAINER_MICHAEL_SET_RCU_H
+/*
+ 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
#include <cds/container/details/michael_set_base.h>
#include <cds/details/allocator.h>
Template parameters are:
- \p RCU - one of \ref cds_urcu_gc "RCU type"
- - \p OrderedList - ordered list implementation used as the bucket for hash set, for example,
+ - \p OrderedList - ordered list implementation used as the bucket for hash set, for example,
\ref cds_nonintrusive_MichaelList_rcu "MichaelList".
The ordered list implementation specifies the type \p T stored in the hash-set,
the comparison functor for the type \p T and other features specific for
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
/// 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;
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
public:
/// Initialize hash set
- /** @copydetails cds_nonintrusive_MichaelHashSet_hp_ctor
+ /**
+ The Michael's hash set is non-expandable container. You should point the average count of items \p nMaxItemCount
+ when you create an object.
+ \p nLoadFactor parameter defines average count of items per bucket and it should be small number between 1 and 10.
+ Remember, since the bucket implementation is an ordered list, searching in the bucket is linear [<tt>O(nLoadFactor)</tt>].
+
+ The ctor defines hash table size as rounding <tt>nMaxItemCount / nLoadFactor</tt> up to nearest power of two.
*/
MichaelHashSet(
size_t nMaxItemCount, ///< estimation of max item count in the hash set
// 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
+
+ /// Updates the element
/**
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:
+ If the item \p val not found in the set, then \p val is inserted iff \p bAllowInsert is \p true.
+ Otherwise, the functor \p func is called with item found.
+ The functor signature is:
\code
- struct my_functor {
- void operator()( bool bNew, value_type& item, const Q& val );
+ struct functor {
+ void operator()( bool bNew, value_type& item, Q const& 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
+ - \p val - argument \p val passed into the \p %update() 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
+ 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.
- @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
+ @warning For \ref cds_intrusive_MichaelList_hp "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
+ \ref cds_intrusive_LazyList_hp "LazyList" provides exclusive access to inserted item and does not require any node-level
synchronization.
*/
template <typename Q, typename Func>
- std::pair<bool, bool> ensure( const Q& val, Func func )
+ std::pair<bool, bool> update( const Q& val, Func func, bool bAllowInsert = true )
{
- std::pair<bool, bool> bRet = bucket( val ).ensure( val, func );
- if ( bRet.first && bRet.second )
+ std::pair<bool, bool> bRet = bucket( val ).update( val, func, bAllowInsert );
+ if ( bRet.second )
++m_ItemCounter;
return bRet;
+ }//@cond
+ template <typename Q, typename Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
+ std::pair<bool, bool> ensure( const Q& val, Func func )
+ {
+ return update( val, func, true );
}
+ //@endcond
/// Inserts data of type \p value_type created from \p args
/**
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;
/// Extracts an item from the set
/** \anchor cds_nonintrusive_MichaelHashSet_rcu_extract
The function searches an item with key equal to \p key in the set,
- unlinks it from the set, places item pointer into \p dest argument, and returns \p true.
- If the item with the key equal to \p key is not found the function return \p false.
+ unlinks it from the set, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item found.
+ If the item with the key equal to \p key is not found the function return an empty \p exempt_ptr.
- @note The function does NOT call RCU read-side lock or synchronization,
- and does NOT dispose the item found. It just excludes the item from the set
- and returns a pointer to item found.
- You should lock RCU before calling of the function, and you should synchronize RCU
- outside the RCU lock to free extracted item
+ 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:
+ - 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.
\code
#include <cds/urcu/general_buffered.h>
rcu_michael_set theSet;
// ...
- rcu_michael_set::exempt_ptr p;
- {
- // first, we should lock RCU
- rcu_michael_set::rcu_lock lock;
-
- // Now, you can apply extract function
- // Note that you must not delete the item found inside the RCU lock
- if ( theSet.extract( p, 10 )) {
- // do something with p
- ...
- }
+ typename rcu_michael_set::exempt_ptr p;
+
+ // For MichaelList we should not lock RCU
+
+ // Note that you must not delete the item found inside the RCU lock
+ p = theSet.extract( 10 );
+ if ( p ) {
+ // do something with p
+ ...
}
// We may safely release p here
\endcode
*/
template <typename Q>
- bool extract( exempt_ptr& dest, Q const& key )
+ exempt_ptr extract( Q const& key )
{
- if ( bucket( key ).extract( dest, key )) {
+ exempt_ptr p = bucket( key ).extract( key );
+ if ( p )
--m_ItemCounter;
- return true;
- }
- return false;
+ return p;
}
/// Extracts an item from the set using \p pred predicate for searching
/**
- The function is an analog of \ref cds_nonintrusive_MichaelHashSet_rcu_extract "extract(exempt_ptr&, Q const&)"
- but \p pred is used for key comparing.
+ The function is an analog of \p extract(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 set.
*/
template <typename Q, typename Less>
- bool extract_with( exempt_ptr& dest, Q const& key, Less pred )
+ exempt_ptr extract_with( Q const& key, Less pred )
{
- if ( bucket( key ).extract_with( dest, key, pred )) {
+ exempt_ptr p = bucket( key ).extract_with( key, pred );
+ if ( p )
--m_ItemCounter;
- return true;
- }
- return false;
+ return p;
}
/// Finds the key \p key
The function returns \p true if \p key is found, \p false otherwise.
*/
template <typename Q, typename Func>
- bool find( Q& key, Func f ) const
+ bool find( Q& key, Func f )
+ {
+ return bucket( key ).find( key, f );
+ }
+ //@cond
+ template <typename Q, typename Func>
+ bool find( Q const& key, Func f )
{
return bucket( key ).find( key, f );
}
+ //@endcond
/// Finds the key \p key using \p pred predicate for searching
/**
\p Less must imply the same element order as the comparator used for building the set.
*/
template <typename Q, typename Less, typename Func>
- bool find_with( Q& key, Less pred, Func f ) const
+ bool find_with( Q& key, Less pred, Func f )
{
return bucket( key ).find_with( key, pred, f );
}
+ //@cond
+ template <typename Q, typename Less, typename Func>
+ bool find_with( Q const& key, Less pred, Func f )
+ {
+ return bucket( key ).find_with( key, pred, f );
+ }
+ //@endcond
- /// Finds the key \p key
- /** \anchor cds_nonintrusive_MichealSet_rcu_find_val
+ /// Checks whether the set 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.
+ and returns \p true if the key is found, and \p false otherwise.
Note the hash functor specified for class \p Traits template parameter
- should accept a parameter of type \p Q that may be not the same as \p value_type.
+ should accept a parameter of type \p Q that can be not the same as \p value_type.
*/
template <typename Q>
- bool find( Q const & key ) const
+ bool contains( Q const& key )
+ {
+ return bucket( key ).contains( key );
+ }
+ //@cond
+ template <typename Q>
+ CDS_DEPRECATED("use contains()")
+ bool find( Q const& key )
{
- return bucket( key ).find( key );
+ return contains( key );
}
+ //@endcond
- /// Finds the key \p key using \p pred predicate for searching
+ /// Checks whether the set contains \p key using \p pred predicate for searching
/**
- The function is an analog of \ref cds_nonintrusive_MichealSet_rcu_find_val "find(Q const&)"
- but \p pred is used for key comparing.
+ 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 set.
*/
template <typename Q, typename Less>
- bool find_with( Q const & key, Less pred ) const
+ bool contains( Q const& key, Less pred )
+ {
+ return bucket( key ).contains( key, pred );
+ }
+ //@cond
+ template <typename Q, typename Less>
+ CDS_DEPRECATED("use contains()")
+ bool find_with( Q const& key, Less pred )
{
- return bucket( key ).find_with( key, pred );
+ 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.
+ 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.
\code
typedef cds::container::MichaelHashSet< your_template_parameters > hash_set;
hash_set theSet;
+ typename hash_set::raw_ptr gp;
// ...
{
// Lock RCU
hash_set::rcu_lock lock;
- foo * pVal = theSet.get( 5 );
- if ( pVal ) {
+ gp = theSet.get( 5 );
+ if ( gp ) {
// Deal with pVal
//...
}
// Unlock RCU by rcu_lock destructor
- // pVal can be freed at any time after RCU has been unlocked
+ // gp can be reclaimed at any time after RCU has been unlocked
}
\endcode
*/
template <typename Q>
- value_type * get( Q const& key ) const
+ raw_ptr get( Q const& key )
{
return bucket( key ).get( key );
}
\p pred must imply the same element order as the comparator used for building the set.
*/
template <typename Q, typename Less>
- value_type * get_with( Q const& key, Less pred ) const
+ raw_ptr get_with( Q const& key, Less pred )
{
return bucket( key ).get_with( key, pred );
}
}} // namespace cds::container
-#endif // ifndef __CDS_CONTAINER_MICHAEL_SET_RCU_H
+#endif // ifndef CDSLIB_CONTAINER_MICHAEL_SET_RCU_H
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