cds  2.3.1
cds::intrusive::SplitListSet< GC, OrderedList, Traits > Class Template Reference

Split-ordered list. More...

#include <cds/intrusive/split_list.h>

Public Types

typedef GC gc
 Garbage collector.
 
typedef Traits traits
 Set traits.
 
typedef OrderedList ordered_list
 type of ordered list used as a base for split-list
 
typedef ordered_list::value_type value_type
 type of value stored in the split-list
 
typedef ordered_list::key_comparator key_comparator
 key comparison functor
 
typedef ordered_list::disposer disposer
 Node disposer functor.
 
typedef cds::opt::v::hash_selector< typename traits::hash >::type hash
 Hash functor for value_type and all its derivatives you use.
 
typedef traits::bit_reversal bit_reversal
 Bit reversal algorithm, see split_list::traits::bit_reversal.
 
typedef traits::item_counter item_counter
 Item counter type.
 
typedef traits::back_off back_off
 back-off strategy for spinning
 
typedef traits::memory_model memory_model
 Memory ordering. See cds::opt::memory_model option.
 
typedef traits::stat stat
 Internal statistics, see spit_list::stat.
 
typedef ordered_list::guarded_ptr guarded_ptr
 Guarded pointer.
 

Public Member Functions

 SplitListSet ()
 Initialize split-ordered list of default capacity. More...
 
 SplitListSet (size_t nItemCount, size_t nLoadFactor=1)
 Initialize split-ordered list. More...
 
 ~SplitListSet ()
 Destroys split-list set.
 
bool insert (value_type &val)
 Inserts new node. More...
 
template<typename Func >
bool insert (value_type &val, Func f)
 Inserts new node. More...
 
template<typename Func >
std::pair< bool, bool > update (value_type &val, Func func, bool bAllowInsert=true)
 Updates the node. More...
 
std::pair< bool, bool > upsert (value_type &val, bool bAllowInsert=true)
 Inserts or updates the node (only for IterableList) More...
 
bool unlink (value_type &val)
 Unlinks the item val from the set. More...
 
template<typename Q >
bool erase (Q const &key)
 Deletes the item from the set. More...
 
template<typename Q , typename Less >
bool erase_with (const Q &key, Less pred)
 Deletes the item from the set with comparing functor pred. More...
 
template<typename Q , typename Func >
bool erase (Q const &key, Func f)
 Deletes the item from the set. More...
 
template<typename Q , typename Less , typename Func >
bool erase_with (Q const &key, Less pred, Func f)
 Deletes the item from the set with comparing functor pred. More...
 
bool erase_at (iterator const &iter)
 Deletes the item pointed by iterator iter (only for IterableList based set) More...
 
template<typename Q >
guarded_ptr extract (Q const &key)
 Extracts the item with specified key. More...
 
template<typename Q , typename Less >
guarded_ptr extract_with (Q const &key, Less pred)
 Extracts the item using compare functor pred. More...
 
template<typename Q , typename Func >
bool find (Q &key, Func f)
 Finds the key key. More...
 
template<typename Q >
iterator find (Q &key)
 Finds key and returns iterator pointed to the item found (only for IterableList) More...
 
template<typename Q , typename Less , typename Func >
bool find_with (Q &key, Less pred, Func f)
 Finds the key key with pred predicate for comparing. More...
 
template<typename Q , typename Less >
iterator find_with (Q &key, Less pred)
 Finds key using pred predicate and returns iterator pointed to the item found (only for IterableList) More...
 
template<typename Q >
bool contains (Q const &key)
 Checks whether the set contains key. More...
 
template<typename Q , typename Less >
bool contains (Q const &key, Less pred)
 Checks whether the set contains key using pred predicate for searching. More...
 
template<typename Q >
guarded_ptr get (Q const &key)
 Finds the key key and return the item found. More...
 
template<typename Q , typename Less >
guarded_ptr get_with (Q const &key, Less pred)
 Finds the key key and return the item found. More...
 
size_t size () const
 Returns item count in the set.
 
bool empty () const
 Checks if the set is empty. More...
 
void clear ()
 Clears the set (non-atomic) More...
 
stat const & statistics () const
 Returns internal statistics.
 
OrderedList::stat const & list_statistics () const
 Returns internal statistics for OrderedList.
 

Static Public Attributes

static constexpr const size_t c_nHazardPtrCount = ordered_list::c_nHazardPtrCount + 4
 Count of hazard pointer required.
 

Forward iterators

typedef iterator_type< false > iterator
 Forward iterator. More...
 
typedef iterator_type< true > const_iterator
 Const forward iterator. More...
 
iterator begin ()
 Returns a forward iterator addressing the first element in a split-list. More...
 
iterator end ()
 Returns an iterator that addresses the location succeeding the last element in a split-list. More...
 
const_iterator begin () const
 Returns a forward const iterator addressing the first element in a split-list.
 
const_iterator cbegin () const
 Returns a forward const iterator addressing the first element in a split-list.
 
const_iterator end () const
 Returns an const iterator that addresses the location succeeding the last element in a split-list.
 
const_iterator cend () const
 Returns an const iterator that addresses the location succeeding the last element in a split-list.
 

Detailed Description

template<class GC, class OrderedList, class Traits = split_list::traits>
class cds::intrusive::SplitListSet< GC, OrderedList, Traits >

Split-ordered list.

Hash table implementation based on split-ordered list algorithm discovered by Ori Shalev and Nir Shavit, see

  • [2003] Ori Shalev, Nir Shavit "Split-Ordered Lists - Lock-free Resizable Hash Tables"
  • [2008] Nir Shavit "The Art of Multiprocessor Programming"

The split-ordered list is a lock-free implementation of an extensible unbounded hash table. It uses original recursive split-ordering algorithm discovered by Ori Shalev and Nir Shavit that allows to split buckets without item moving on resizing.

Short description [from [2003] Ori Shalev, Nir Shavit "Split-Ordered Lists - Lock-free Resizable Hash Tables"]

The algorithm keeps all the items in one lock-free linked list, and gradually assigns the bucket pointers to the places in the list where a sublist of 'correct' items can be found. A bucket is initialized upon first access by assigning it to a new 'dummy' node (dashed contour) in the list, preceding all items that should be in that bucket. A newly created bucket splits an older bucket's chain, reducing the access cost to its items. The table uses a modulo 2**i hash (there are known techniques for 'pre-hashing' before a modulo 2**i hash to overcome possible binary correlations among values). The table starts at size 2 and repeatedly doubles in size.

Unlike moving an item, the operation of directing a bucket pointer can be done in a single CAS operation, and since items are not moved, they are never 'lost'. However, to make this approach work, one must be able to keep the items in the list sorted in such a way that any bucket's sublist can be 'split' by directing a new bucket pointer within it. This operation must be recursively repeatable, as every split bucket may be split again and again as the hash table grows. To achieve this goal the authors introduced recursive split-ordering, a new ordering on keys that keeps items in a given bucket adjacent in the list throughout the repeated splitting process.

Magically, yet perhaps not surprisingly, recursive split-ordering is achieved by simple binary reversal: reversing the bits of the hash key so that the new key's most significant bits (MSB) are those that were originally its least significant. The split-order keys of regular nodes are exactly the bit-reverse image of the original keys after turning on their MSB. For example, items 9 and 13 are in the 1 mod 4 bucket, which can be recursively split in two by inserting a new node between them.

To insert (respectively delete or search for) an item in the hash table, hash its key to the appropriate bucket using recursive split-ordering, follow the pointer to the appropriate location in the sorted items list, and traverse the list until the key's proper location in the split-ordering (respectively until the key or a key indicating the item is not in the list is found). Because of the combinatorial structure induced by the split-ordering, this will require traversal of no more than an expected constant number of items.

The design is modular: to implement the ordered items list, you can use one of several non-blocking list-based set algorithms: MichaelList, LazyList.

Implementation

Template parameters are:

  • GC - Garbage collector. Note the GC must be the same as the GC used for OrderedList
  • OrderedList - ordered list implementation used as a bucket for hash set, for example, MichaelList, LazyList. The intrusive ordered list implementation specifies the type T stored in the split-list set, the comparison functor for the type T and other features specific for the ordered list.
  • Traits - split-list traits, default is split_list::traits. Instead of defining Traits struct you can use option-based syntax provided by split_list::make_traits metafunction.

There are several specialization of the split-list class for different GC:

Hash functor

Some member functions of split-ordered list accept the key parameter of type Q which differs from value_type. It is expected that type Q contains full key of value_type, and for equal keys of type Q and value_type the hash values of these keys must be equal too. The hash functor Traits::hash should accept parameters of both type:

// Our node type
struct Foo {
std::string key_ ; // key field
// ... other fields
};
// Hash functor
struct fooHash {
size_t operator()( const std::string& s ) const
{
return std::hash( s );
}
size_t operator()( const Foo& f ) const
{
return (*this)( f.key_ );
}
};

How to use

Split-list based on IterableList differs from split-list based on MichaelList or LazyList because IterableList stores data "as is" - it cannot use any hook.

Suppose, your split-list contains values of type Foo. For MichaelList and LazyList, Foo declaration should be based on ordered-list node:

For IterableList, Foo should be based on void:

struct Foo: public cds::intrusive::split_list::node<void>
{
// ... field declarations
};

Everything else is the same. Consider split-list based on MichaelList.

First, you should choose ordered list type to use in your split-list set:

// For gc::HP-based MichaelList implementation
#include <cds/intrusive/michael_list_hp.h>
// cds::intrusive::SplitListSet declaration
#include <cds/intrusive/split_list.h>
// Type of set items
// Note you should declare your struct based on cds::intrusive::split_list::node
// which is a wrapper for ordered-list node struct.
// In our case, the node type for HP-based MichaelList is cds::intrusive::michael_list::node< cds::gc::HP >
struct Foo: public cds::intrusive::split_list::node< cds::intrusive::michael_list::node< cds::gc::HP > >
{
std::string key_ ; // key field
unsigned val_ ; // value field
// ... other value fields
};
// Declare comparator for the item
struct FooCmp
{
int operator()( const Foo& f1, const Foo& f2 ) const
{
return f1.key_.compare( f2.key_ );
}
};
// Declare base ordered-list type for split-list
// hook option
// item comparator option
>::type
> Foo_list;

Second, you should declare split-list set container:

// Declare hash functor
// Note, the hash functor accepts parameter type Foo and std::string
struct FooHash {
size_t operator()( const Foo& f ) const
{
return cds::opt::v::hash<std::string>()( f.key_ );
}
size_t operator()( const std::string& s ) const
{
return cds::opt::v::hash<std::string>()( s );
}
};
// Split-list set typedef
cds::gc::HP
,Foo_list
>::type
> Foo_set;

Now, you can use Foo_set in your application.

Foo_set fooSet;
Foo * foo = new Foo;
foo->key_ = "First";
fooSet.insert( *foo );
// and so on ...

Member Typedef Documentation

◆ const_iterator

template<class GC, class OrderedList, class Traits = split_list::traits>
typedef iterator_type<true> cds::intrusive::SplitListSet< GC, OrderedList, Traits >::const_iterator

Const forward iterator.

For iterator's features and requirements see iterator

◆ iterator

template<class GC, class OrderedList, class Traits = split_list::traits>
typedef iterator_type<false> cds::intrusive::SplitListSet< GC, OrderedList, Traits >::iterator

Forward iterator.

The forward iterator is based on OrderedList forward iterator and has some features:

  • it has no post-increment operator
  • it iterates items in unordered fashion
  • iterator cannot be moved across thread boundary because it may contain GC's guard that is thread-private GC data.

Iterator thread safety depends on type of OrderedList:

  • for MichaelList and LazyList: 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 set. 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 IterableList: iterator is thread-safe. You may use it freely in concurrent environment.

Constructor & Destructor Documentation

◆ SplitListSet() [1/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
cds::intrusive::SplitListSet< GC, OrderedList, Traits >::SplitListSet ( )
inline

Initialize split-ordered list of default capacity.

The default capacity is defined in bucket table constructor. See split_list::expandable_bucket_table, split_list::static_bucket_table which selects by split_list::dynamic_bucket_table option.

◆ SplitListSet() [2/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
cds::intrusive::SplitListSet< GC, OrderedList, Traits >::SplitListSet ( size_t  nItemCount,
size_t  nLoadFactor = 1 
)
inline

Initialize split-ordered list.

Parameters
nItemCountestimate average of item count
nLoadFactorload factor - average item count per bucket. Small integer up to 8, default is 1.

Member Function Documentation

◆ begin()

template<class GC, class OrderedList, class Traits = split_list::traits>
iterator cds::intrusive::SplitListSet< GC, OrderedList, Traits >::begin ( )
inline

Returns a forward iterator addressing the first element in a split-list.

For empty list

begin() == end()

◆ clear()

template<class GC, class OrderedList, class Traits = split_list::traits>
void cds::intrusive::SplitListSet< GC, OrderedList, Traits >::clear ( )
inline

Clears the set (non-atomic)

The function unlink all items from the set. The function is not atomic. After call the split-list can be non-empty.

For each item the disposer is called after unlinking.

◆ contains() [1/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q >
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::contains ( Q const &  key)
inline

Checks whether the set contains key.

The function searches the item with key equal to key and returns true if it is found, and false otherwise.

Note the hash functor specified for class Traits template parameter should accept a parameter of type Q that can be not the same as value_type. Otherwise, you may use contains( Q const&, Less pred ) functions with explicit predicate for key comparing.

◆ contains() [2/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q , typename Less >
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::contains ( Q const &  key,
Less  pred 
)
inline

Checks whether the set contains key using pred predicate for searching.

The function is an analog of contains( key ) but pred is used for key comparing. Less functor has the interface like std::less. Less must imply the same element order as the comparator used for building the set.

◆ empty()

template<class GC, class OrderedList, class Traits = split_list::traits>
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::empty ( ) const
inline

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 split-list set implementation.

◆ end()

template<class GC, class OrderedList, class Traits = split_list::traits>
iterator cds::intrusive::SplitListSet< GC, OrderedList, Traits >::end ( )
inline

Returns an iterator that addresses the location succeeding the last element in a split-list.

Do not use the value returned by end function to access any item.

The returned value can be used only to control reaching the end of the split-list. For empty list

begin() == end()

◆ erase() [1/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q >
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::erase ( Q const &  key)
inline

Deletes the item from the set.

The function searches an item with key equal to key in the set, unlinks it from the set, and returns true. If the item with key equal to key is not found the function return false.

Difference between erase and unlink functions: erase finds a key and deletes the item found. unlink finds an item by key and deletes it only if key is an item of that set, i.e. the pointer to item found is equal to &key .

Note the hash functor should accept a parameter of type Q that can be not the same as value_type.

◆ erase() [2/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q , typename Func >
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::erase ( Q const &  key,
Func  f 
)
inline

Deletes the item from the set.

The function searches an item with key equal to key in the set, call f functor with item found, unlinks it from the set, and returns true. The disposer specified by OrderedList class template parameter is called by garbage collector GC asynchronously.

The Func interface is

struct functor {
void operator()( value_type const& item );
};

If the item with key equal to key is not found the function return false.

Note the hash functor should accept a parameter of type Q that can be not the same as value_type.

◆ erase_at()

template<class GC, class OrderedList, class Traits = split_list::traits>
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::erase_at ( iterator const &  iter)
inline

Deletes the item pointed by iterator iter (only for IterableList based set)

Returns true if the operation is successful, false otherwise. The function can return 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
erase_at() is supported only for SplitListSet based on IterableList.

◆ erase_with() [1/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q , typename Less >
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::erase_with ( const Q &  key,
Less  pred 
)
inline

Deletes the item from the set with comparing functor pred.

The function is an analog of erase(Q const&) but pred predicate is used for key comparing. Less has the interface like std::less. pred must imply the same element order as the comparator used for building the set.

◆ erase_with() [2/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q , typename Less , typename Func >
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::erase_with ( Q const &  key,
Less  pred,
Func  f 
)
inline

Deletes the item from the set with comparing functor pred.

The function is an analog of erase(Q const&, Func) but pred predicate is used for key comparing. Less has the interface like std::less. pred must imply the same element order as the comparator used for building the set.

◆ extract()

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q >
guarded_ptr cds::intrusive::SplitListSet< GC, OrderedList, Traits >::extract ( Q const &  key)
inline

Extracts the item with specified key.

The function searches an item with key equal to key, unlinks it from the set, and returns it as guarded_ptr. If key is not found the function returns an empty guarded pointer.

Note the compare functor should accept a parameter of type Q that may be not the same as value_type.

The disposer specified in OrderedList class' template parameter is called automatically by garbage collector GC when returned guarded_ptr object will be destroyed or released.

Note
Each guarded_ptr object uses the GC's guard that can be limited resource.

Usage:

splitlist_set theSet;
// ...
{
splitlist_set::guarded_ptr gp( theSet.extract( 5 ));
if ( gp) {
// Deal with gp
// ...
}
// Destructor of gp releases internal HP guard
}

◆ extract_with()

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q , typename Less >
guarded_ptr cds::intrusive::SplitListSet< GC, OrderedList, Traits >::extract_with ( Q const &  key,
Less  pred 
)
inline

Extracts the item using compare functor pred.

The function is an analog of extract(Q const&) but pred predicate is used for key comparing.

Less functor has the semantics like std::less but should take arguments of type value_type and Q in any order. pred must imply the same element order as the comparator used for building the set.

◆ find() [1/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q , typename Func >
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::find ( Q &  key,
Func  f 
)
inline

Finds the key key.

The function searches the item with key equal to key and calls the functor f for item found. The interface of Func functor is:

struct functor {
void operator()( value_type& item, Q& key );
};

where item is the item found, key is the find function argument.

The functor can change non-key fields of item. Note that the functor is only guarantee that item cannot be disposed during functor is executing. The functor does not serialize simultaneous access to the set item. If such access is possible you must provide your own synchronization schema on item level to exclude unsafe item modifications.

Note the hash functor specified for class Traits template parameter should accept a parameter of type Q that can be not the same as value_type.

The function returns true if key is found, false otherwise.

◆ find() [2/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q >
iterator cds::intrusive::SplitListSet< GC, OrderedList, Traits >::find ( Q &  key)
inline

Finds key and returns iterator pointed to the item found (only for IterableList)

If key is not found the function returns end().

Note
This function is supported only for the set based on IterableList

◆ find_with() [1/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q , typename Less , typename Func >
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::find_with ( Q &  key,
Less  pred,
Func  f 
)
inline

Finds the key key with pred predicate for comparing.

The function is an analog of find(Q&, Func) but cmp is used for key compare. Less has the interface like std::less. cmp must imply the same element order as the comparator used for building the set.

◆ find_with() [2/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q , typename Less >
iterator cds::intrusive::SplitListSet< GC, OrderedList, Traits >::find_with ( Q &  key,
Less  pred 
)
inline

Finds key using pred predicate and returns iterator pointed to the item found (only for IterableList)

The function is an analog of find(Q&) but pred is used for key comparing. Less functor has the interface like std::less. pred must imply the same element order as the comparator used for building the set.

If key is not found the function returns end().

Note
This function is supported only for the set based on IterableList

◆ get()

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q >
guarded_ptr cds::intrusive::SplitListSet< GC, OrderedList, Traits >::get ( Q const &  key)
inline

Finds the key key and return the item found.

The function searches the item with key equal to key and returns the item found as guarded_ptr. If key is not found the function returns an empty guarded pointer.

The disposer specified in OrderedList class' template parameter is called by garbage collector GC automatically when returned guarded_ptr object will be destroyed or released.

Note
Each guarded_ptr object uses one GC's guard which can be limited resource.

Usage:

splitlist_set theSet;
// ...
{
splitlist_set::guarded_ptr gp = theSet.get( 5 );
if ( gp ) {
// Deal with gp
//...
}
// Destructor of guarded_ptr releases internal HP guard
}

Note the compare functor specified for OrderedList template parameter should accept a parameter of type Q that can be not the same as value_type.

◆ get_with()

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Q , typename Less >
guarded_ptr cds::intrusive::SplitListSet< GC, OrderedList, Traits >::get_with ( Q const &  key,
Less  pred 
)
inline

Finds the key key and return the item found.

The function is an analog of get( Q const&) but pred is used for comparing the keys.

Less functor has the semantics like std::less but should take arguments of type value_type and Q in any order. pred must imply the same element order as the comparator used for building the set.

◆ insert() [1/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::insert ( value_type val)
inline

Inserts new node.

The function inserts val in the set if it does not contain an item with key equal to val.

Returns true if val is placed into the set, false otherwise.

◆ insert() [2/2]

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Func >
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::insert ( value_type val,
Func  f 
)
inline

Inserts new node.

This function is intended for derived non-intrusive containers.

The function allows to split creating of new item into two part:

  • create item with key only
  • insert new item into the set
  • if inserting is success, calls f functor to initialize value-field of val.

The functor signature is:

void func( value_type& val );

where val is the item inserted. The user-defined functor is called only if the inserting is success.

Warning
For MichaelList as the bucket see insert item troubleshooting. LazyList provides exclusive access to inserted item and does not require any node-level synchronization.

◆ unlink()

template<class GC, class OrderedList, class Traits = split_list::traits>
bool cds::intrusive::SplitListSet< GC, OrderedList, Traits >::unlink ( value_type val)
inline

Unlinks the item val from the set.

The function searches the item val in the set and unlinks it from the set if it is found and is equal to val.

Difference between erase and unlink functions: erase finds a key and deletes the item found. unlink finds an item by key and deletes it only if val is an item of that set, i.e. the pointer to item found is equal to &val .

The function returns true if success and false otherwise.

◆ update()

template<class GC, class OrderedList, class Traits = split_list::traits>
template<typename Func >
std::pair<bool, bool> cds::intrusive::SplitListSet< GC, OrderedList, Traits >::update ( value_type val,
Func  func,
bool  bAllowInsert = true 
)
inline

Updates the node.

The operation performs inserting or changing data with lock-free manner.

If the item val is not found in the set, then val is inserted iff bAllowInsert is true. Otherwise, the functor func is called with item found.

The functor signature depends of the type of OrderedList:

for MichaelList, LazyList

struct functor {
void operator()( bool bNew, value_type& item, value_type& val );
};

with arguments:

  • bNew - true if the item has been inserted, false otherwise
  • item - item of the set
  • val - argument val passed into the update() function If new item has been inserted (i.e. bNew is true) then item and val arguments refers to the same thing.

The functor may change non-key fields of the item.

Warning
For MichaelList as the bucket see insert item troubleshooting. LazyList provides exclusive access to inserted item and does not require any node-level synchronization.

for IterableList

void func( value_type& val, value_type * old );

where

  • val - argument val passed into the update() function
  • old - old value that will be retired. If new item has been inserted then old is nullptr.

Returns std::pair<bool, bool> where first is true if operation is successful, second is true if new item has been added or false if the item with val already is in the list.

◆ upsert()

template<class GC, class OrderedList, class Traits = split_list::traits>
std::pair<bool, bool> cds::intrusive::SplitListSet< GC, OrderedList, Traits >::upsert ( value_type val,
bool  bAllowInsert = true 
)
inline

Inserts or updates the node (only for IterableList)

The operation performs inserting or changing data with lock-free manner.

If the item val is not found in the set, then val is inserted iff bAllowInsert is true. Otherwise, the current element is changed to val, the old element will be retired later by call Traits::disposer.

Returns std::pair<bool, bool> where first is true if operation is successful, second is true if val has been added or false if the item with that key already in the set.


The documentation for this class was generated from the following file:

cds 2.3.1 Developed by Maxim Khizhinsky aka khizmax 2007 - 2017
Autogenerated Fri Sep 1 2017 08:47:24 by Doxygen 1.8.13