X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=cds%2Fcontainer%2Fmichael_map.h;h=9947409d7643e722d8e72eb3e362c15b0ec4507c;hb=6924946ceeaae28bc227fe7c9d8e939963bb9d69;hp=38bce26dba7c98b5921f47918a265b3949508ec3;hpb=f3d187182434846ab9608307037258421101feb9;p=libcds.git diff --git a/cds/container/michael_map.h b/cds/container/michael_map.h index 38bce26d..9947409d 100644 --- a/cds/container/michael_map.h +++ b/cds/container/michael_map.h @@ -1,11 +1,11 @@ /* This file is a part of libcds - Concurrent Data Structures library - (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016 + (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: @@ -32,6 +32,7 @@ #define CDSLIB_CONTAINER_MICHAEL_MAP_H #include +#include #include namespace cds { namespace container { @@ -52,10 +53,10 @@ namespace cds { namespace container { - \p GC - Garbage collector used. You may use any \ref cds_garbage_collector "Garbage collector" from the \p libcds library. Note the \p GC must be the same as the GC used for \p OrderedList - - \p OrderedList - ordered key-value list implementation used as bucket for hash map, for example, \p MichaelKVList - or \p LazyKVList. The ordered list implementation specifies the \p Key and \p Value types stored in the hash-map, - the reclamation schema \p GC used by hash-map, the comparison functor for the type \p Key and other features - specific for the ordered list. + - \p OrderedList - ordered key-value list implementation used as bucket for hash map, for example, \p MichaelKVList, + \p LazyKVList, \p IterableKVList. The ordered list implementation specifies the \p Key and \p Value types + stored in the hash-map, the reclamation schema \p GC used by hash-map, the comparison functor for the type \p Key + and other features specific for the ordered list. - \p Traits - map traits, default is \p michael_map::traits. Instead of defining \p Traits struct you may use option-based syntax with \p michael_map::make_traits metafunction. @@ -63,7 +64,7 @@ namespace cds { namespace container { \p key_type and an argument of template type \p K must meet the following requirements: - \p key_type should be constructible from value of type \p K; - the hash functor should be able to calculate correct hash value from argument \p key of type \p K: - hash( key_type(key) ) == hash( key ) + hash( key_type(key)) == hash( key ) - values of type \p key_type and \p K should be comparable There are the specializations: @@ -147,60 +148,60 @@ namespace cds { namespace container { class MichaelHashMap { public: - typedef GC gc; ///< Garbage collector - typedef OrderedList bucket_type; ///< type of ordered list to be used as a bucket - typedef Traits traits; ///< Map traits + typedef GC gc; ///< Garbage collector + typedef OrderedList ordered_list; ///< type of ordered list to be used as a bucket + typedef Traits traits; ///< Map traits - typedef typename bucket_type::key_type key_type; ///< key type - typedef typename bucket_type::mapped_type mapped_type; ///< value type - typedef typename bucket_type::value_type value_type; ///< key/value pair stored in the map + typedef typename ordered_list::key_type key_type; ///< key type + typedef typename ordered_list::mapped_type mapped_type; ///< value type + typedef typename ordered_list::value_type value_type; ///< key/value pair stored in the map + typedef typename traits::allocator allocator; ///< Bucket table allocator - typedef typename bucket_type::key_comparator key_comparator; ///< key compare functor + typedef typename ordered_list::key_comparator key_comparator; ///< key compare functor +#ifdef CDS_DOXYGEN_INVOKED + typedef typename ordered_list::stat stat; ///< Internal statistics + /// Guarded pointer - a result of \p get() and \p extract() functions + typedef typename ordered_list::guarded_ptr guarded_ptr; +#endif /// Hash functor for \ref key_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 - /// Bucket table allocator - typedef cds::details::Allocator< bucket_type, typename traits::allocator > bucket_table_allocator; - typedef typename bucket_type::guarded_ptr guarded_ptr; ///< Guarded pointer + // GC and OrderedList::gc must be the same + static_assert( std::is_same::value, "GC and OrderedList::gc must be the same"); - static CDS_CONSTEXPR const size_t c_nHazardPtrCount = bucket_type::c_nHazardPtrCount; ///< Count of hazard pointer required - - protected: - item_counter m_ItemCounter; ///< Item counter - hash m_HashFunctor; ///< Hash functor - bucket_type * m_Buckets; ///< bucket table + static CDS_CONSTEXPR const size_t c_nHazardPtrCount = ordered_list::c_nHazardPtrCount; ///< Count of hazard pointer required - 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; + + typedef typename internal_bucket_type::guarded_ptr guarded_ptr; + typedef typename allocator::template rebind< internal_bucket_type >::other bucket_table_allocator; + typedef typename bucket_stat::stat stat; //@endcond protected: //@cond - /// Calculates hash value of \p key - template - size_t hash_value( Q const& key ) const - { - return m_HashFunctor( key ) & m_nHashBitmask; - } - - /// Returns the bucket (ordered list) for \p key - template - bucket_type& bucket( Q const& key ) - { - return m_Buckets[ hash_value( key ) ]; - } + const size_t m_nHashBitmask; + internal_bucket_type* m_Buckets; ///< bucket table + hash m_HashFunctor; ///< Hash functor + item_counter m_ItemCounter; ///< Item counter + stat m_Stat; ///< Internal statistics //@endcond protected: //@cond /// Forward iterator template - class iterator_type: private cds::intrusive::michael_set::details::iterator< bucket_type, IsConst > + class iterator_type: protected cds::intrusive::michael_set::details::iterator< internal_bucket_type, IsConst > { - typedef cds::intrusive::michael_set::details::iterator< bucket_type, IsConst > base_class; + typedef cds::intrusive::michael_set::details::iterator< internal_bucket_type, IsConst > base_class; friend class MichaelHashMap; protected: @@ -270,13 +271,13 @@ namespace cds { namespace container { /// Equality operator template - bool operator ==(iterator_type const& i ) + bool operator ==(iterator_type const& i ) const { return base_class::operator ==( i ); } /// Equality operator template - bool operator !=(iterator_type const& i ) + bool operator !=(iterator_type const& i ) const { return !( *this == i ); } @@ -288,38 +289,44 @@ namespace cds { namespace container { //@{ /// Forward iterator /** - The iteration is unordered. - The iterator object is thread-safe: the element pointed by the iterator object is guarded, - so, the element cannot be reclaimed while the iterator object is alive. - However, passing an iterator object between threads is dangerous. - - @warning Due to concurrent nature of Michael's map it is not guarantee that you can iterate - all elements in the map: any concurrent deletion can exclude the element - pointed by the iterator from the map, and your iteration can be terminated - before end of the map. Therefore, such iteration is more suitable for debugging purpose only. - - Remember, each iterator object requires an additional hazard pointer, that may be - a limited resource for \p GC like \p gc::HP (for \p gc::DHP the count of - guards is unlimited). - - The iterator class supports the following minimalistic interface: + The forward iterator for Michael's map 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 (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 because it contains thread-private GC's guard. + + Iterator thread safety depends on type of \p OrderedList: + - for \p MichaelKVList and \p LazyKVList: iterator guarantees safety even if you delete the item that iterator points to + because that item is guarded by hazard pointer. + However, in case of concurrent deleting operations it is no guarantee that you iterate all item in the map. + Moreover, a crash is possible when you try to iterate the next element that has been deleted by concurrent thread. + Use this iterator on the concurrent container for debugging purpose only. + - for \p IterableList: iterator is thread-safe. You may use it freely in concurrent environment. + + The iterator interface: \code - struct iterator { - // Default ctor + class iterator { + public: + // Default constructor iterator(); - // Copy ctor - iterator( iterator const& s); + // Copy construtor + iterator( iterator const& src ); + // Dereference operator value_type * operator ->() const; + + // Dereference operator value_type& operator *() const; - // Pre-increment + // Preincrement operator iterator& operator ++(); - // Copy assignment + // Assignment operator iterator& operator = (iterator const& src); + // Equality operators bool operator ==(iterator const& i ) const; bool operator !=(iterator const& i ) const; }; @@ -338,7 +345,7 @@ namespace cds { namespace container { */ iterator begin() { - return iterator( m_Buckets[0].begin(), m_Buckets, m_Buckets + bucket_count() ); + return iterator( bucket_begin()->begin(), bucket_begin(), bucket_end()); } /// Returns an iterator that addresses the location succeeding the last element in a map @@ -349,7 +356,7 @@ namespace cds { namespace container { */ iterator end() { - return iterator( m_Buckets[bucket_count() - 1].end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() ); + return iterator( bucket_end()[-1].end(), bucket_end() - 1, bucket_end()); } /// Returns a forward const iterator addressing the first element in a map @@ -375,18 +382,6 @@ namespace cds { namespace container { } //@} - private: - //@cond - const_iterator get_const_begin() const - { - return const_iterator( const_cast(m_Buckets[0]).begin(), m_Buckets, m_Buckets + bucket_count() ); - } - const_iterator get_const_end() const - { - return const_iterator( const_cast(m_Buckets[bucket_count() - 1]).end(), m_Buckets + bucket_count() - 1, m_Buckets + bucket_count() ); - } - //@endcond - public: /// Initializes the map /** @anchor cds_nonintrusive_MichaelHashMap_hp_ctor @@ -401,23 +396,22 @@ namespace cds { namespace container { MichaelHashMap( size_t nMaxItemCount, ///< estimation of max item count in the hash map size_t nLoadFactor ///< load factor: estimation of max number of items in the bucket - ) : m_nHashBitmask( michael_map::details::init_hash_bitmask( nMaxItemCount, nLoadFactor )) + ) + : m_nHashBitmask( michael_map::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::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::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( it ); } /// Clears hash map and destroys it ~MichaelHashMap() { 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 with key and default value @@ -432,9 +426,9 @@ namespace cds { namespace container { Returns \p true if inserting successful, \p false otherwise. */ template - bool insert( const K& key ) + bool insert( K&& key ) { - const bool bRet = bucket( key ).insert( key ); + const bool bRet = bucket( key ).insert( std::forward( key )); if ( bRet ) ++m_ItemCounter; return bRet; @@ -452,9 +446,9 @@ namespace cds { namespace container { Returns \p true if \p val is inserted into the map, \p false otherwise. */ template - bool insert( K const& key, V const& val ) + bool insert( K&& key, V&& val ) { - const bool bRet = bucket( key ).insert( key, val ); + const bool bRet = bucket( key ).insert( std::forward( key ), std::forward( val )); if ( bRet ) ++m_ItemCounter; return bRet; @@ -492,9 +486,9 @@ namespace cds { namespace container { synchronization. */ template - bool insert_with( const K& key, Func func ) + bool insert_with( K&& key, Func func ) { - const bool bRet = bucket( key ).insert_with( key, func ); + const bool bRet = bucket( key ).insert_with( std::forward( key ), func ); if ( bRet ) ++m_ItemCounter; return bRet; @@ -509,7 +503,9 @@ namespace cds { namespace container { (note that in this case the \ref key_type should be constructible from type \p K). Otherwise, if \p key is found, the functor \p func is called with item found. - The functor \p Func signature is: + The functor \p func signature depends on \p OrderedList: + + for \p MichaelKVList, \p LazyKVList \code struct my_functor { void operator()( bool bNew, value_type& item ); @@ -521,18 +517,30 @@ namespace cds { namespace container { The functor may change any fields of the \p item.second that is \p mapped_type. - Returns std::pair where \p first is true if operation is successful, + for \p IterableKVList + \code + void func( value_type& val, value_type * old ); + \endcode + where + - \p val - a new data constructed from \p key + - \p old - old value that will be retired. If new item has been inserted then \p old is \p nullptr. + + The functor may change non-key fields of \p val; however, \p func must guarantee + that during changing no any other modifications could be made on this item by concurrent threads. + + @return std::pair where \p first is true if operation is successful, \p second is true if new item has been added or \p false if the item with \p key already exists. - @warning For \ref cds_nonintrusive_MichaelKVList_gc "MichaelKVList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting". + @warning For \ref cds_nonintrusive_MichaelKVList_gc "MichaelKVList" and \ref cds_nonintrusive_IterableKVList_gc "IterableKVList" + as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting". \ref cds_nonintrusive_LazyKVList_gc "LazyKVList" provides exclusive access to inserted item and does not require any node-level synchronization. */ template - std::pair update( K const& key, Func func, bool bAllowInsert = true ) + std::pair update( K&& key, Func func, bool bAllowInsert = true ) { - std::pair bRet = bucket( key ).update( key, func, bAllowInsert ); + std::pair bRet = bucket( key ).update( std::forward( key ), func, bAllowInsert ); if ( bRet.first && bRet.second ) ++m_ItemCounter; return bRet; @@ -549,6 +557,34 @@ namespace cds { namespace container { } //@endcond + /// Inserts or updates the node (only for \p IterableKVList) + /** + The operation performs inserting or changing data with lock-free manner. + + If \p key is not found in the map, then \p key is inserted iff \p bAllowInsert is \p true. + Otherwise, the current element is changed to \p val, the old element will be retired later. + + Returns std::pair 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 map. + */ + template +#ifdef CDS_DOXYGEN_INVOKED + std::pair +#else + typename std::enable_if< + std::is_same< Q, Q>::value && is_iterable_list< ordered_list >::value, + std::pair + >::type +#endif + upsert( Q&& key, V&& val, bool bAllowInsert = true ) + { + std::pair bRet = bucket( val ).upsert( std::forward( key ), std::forward( val ), bAllowInsert ); + if ( bRet.second ) + ++m_ItemCounter; + return bRet; + } + /// For key \p key inserts data of type \p mapped_type created from \p args /** \p key_type should be constructible from type \p K @@ -634,6 +670,34 @@ namespace cds { namespace container { return bRet; } + /// Deletes the item pointed by iterator \p iter (only for \p IterableList based map) + /** + Returns \p true if the operation is successful, \p false otherwise. + The function can return \p false if the node the iterator points to has already been deleted + by other thread. + + The function does not invalidate the iterator, it remains valid and can be used for further traversing. + + @note \p %erase_at() is supported only for \p %MichaelHashMap based on \p IterableList. + */ +#ifdef CDS_DOXYGEN_INVOKED + bool erase_at( iterator const& iter ) +#else + template + typename std::enable_if< std::is_same::value && is_iterable_list< ordered_list >::value, bool >::type + erase_at( Iterator const& iter ) +#endif + { + assert( iter != end()); + assert( iter.bucket() != nullptr ); + + if ( iter.bucket()->erase_at( iter.underlying_iterator())) { + --m_ItemCounter; + return true; + } + return false; + } + /// Extracts the item with specified \p key /** \anchor cds_nonintrusive_MichaelHashMap_hp_extract The function searches an item with key equal to \p key, @@ -712,6 +776,28 @@ namespace cds { namespace container { return bucket( key ).find( key, f ); } + /// Finds \p key and returns iterator pointed to the item found (only for \p IterableList) + /** + If \p key is not found the function returns \p end(). + + @note This function is supported only for map based on \p IterableList + */ + template +#ifdef CDS_DOXYGEN_INVOKED + iterator +#else + typename std::enable_if< std::is_same::value && is_iterable_list< ordered_list >::value, iterator >::type +#endif + find( K const& key ) + { + auto& b = bucket( key ); + auto it = b.find( key ); + if ( it == b.end()) + return end(); + return iterator( it, &b, bucket_end()); + } + + /// Finds the key \p val using \p pred predicate for searching /** The function is an analog of \ref cds_nonintrusive_MichaelMap_find_cfunc "find(K const&, Func)" @@ -725,6 +811,31 @@ namespace cds { namespace container { return bucket( key ).find_with( key, pred, f ); } + /// Finds \p key using \p pred predicate and returns iterator pointed to the item found (only for \p IterableList) + /** + The function is an analog of \p find(K&) 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. + + If \p key is not found the function returns \p end(). + + @note This function is supported only for map based on \p IterableList + */ + template +#ifdef CDS_DOXYGEN_INVOKED + iterator +#else + typename std::enable_if< std::is_same::value && is_iterable_list< ordered_list >::value, iterator >::type +#endif + find_with( K const& key, Less pred ) + { + auto& b = bucket( key ); + auto it = b.find_with( key, pred ); + if ( it == b.end()) + return end(); + return iterator( it, &b, bucket_end()); + } + /// Checks whether the map contains \p key /** The function searches the item with key equal to \p key @@ -735,14 +846,6 @@ namespace cds { namespace container { { return bucket( key ).contains( key ); } - //@cond - template - CDS_DEPRECATED("deprecated, use contains()") - bool find( K const& key ) - { - return bucket( key ).contains( key ); - } - //@endcond /// Checks whether the map contains \p key using \p pred predicate for searching /** @@ -755,14 +858,6 @@ namespace cds { namespace container { { return bucket( key ).contains( key, pred ); } - //@cond - template - CDS_DEPRECATED("deprecated, use contains()") - bool find_with( K const& key, Less pred ) - { - return bucket( key ).contains( key, pred ); - } - //@endcond /// Finds \p key and return the item found /** \anchor cds_nonintrusive_MichaelHashMap_hp_get @@ -821,8 +916,8 @@ namespace cds { namespace container { /// Checks if the map is empty /** - Emptiness is checked by item counting: if item count is zero then the map is empty. - Thus, the correct item counting is an important part of the map implementation. + @warning If you use \p atomicity::empty_item_counter in \p traits::item_counter, + the function always returns \p true. */ bool empty() const { @@ -830,6 +925,10 @@ namespace cds { namespace container { } /// Returns item count in the map + /** + 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; @@ -845,6 +944,63 @@ namespace cds { namespace container { { return m_nHashBitmask + 1; } + + /// Returns const reference to internal statistics + stat const& statistics() const + { + return m_Stat; + } + + protected: + //@cond + /// Calculates hash value of \p key + template + size_t hash_value( Q const& key ) const + { + return m_HashFunctor( key ) & m_nHashBitmask; + } + + /// Returns the bucket (ordered list) for \p key + template + internal_bucket_type& bucket( Q const& key ) + { + return m_Buckets[hash_value( key )]; + } + //@endcond + + private: + //@cond + internal_bucket_type* bucket_begin() const + { + return m_Buckets; + } + + internal_bucket_type* bucket_end() const + { + return m_Buckets + bucket_count(); + } + + const_iterator get_const_begin() const + { + return const_iterator( bucket_begin()->cbegin(), bucket_begin(), bucket_end()); + } + const_iterator get_const_end() const + { + return const_iterator( (bucket_end() - 1)->cend(), bucket_end() - 1, bucket_end()); + } + + template + typename std::enable_if< Stat::empty >::type construct_bucket( internal_bucket_type* b ) + { + new (b) internal_bucket_type; + } + + template + typename std::enable_if< !Stat::empty >::type construct_bucket( internal_bucket_type* b ) + { + new (b) internal_bucket_type( m_Stat ); + } + //@endcond }; }} // namespace cds::container