cds  2.3.1
cds::container::IterableKVList< GC, Key, Value, Traits > Class Template Reference

Iterable ordered list for key-value pair. More...

#include <cds/container/impl/iterable_kvlist.h>

Inheritance diagram for cds::container::IterableKVList< GC, Key, Value, Traits >:
cds::container::IterableList< GC, std::pair< Key, Value >, Traits > cds::intrusive::IterableList< GC, std::pair< Key, Value >, Traits >

Public Types

typedef Key key_type
 Key type.
 
typedef Value mapped_type
 Type of value stored in the list.
 
typedef std::pair< key_type const, mapped_typevalue_type
 key/value pair stored in the list
 
typedef Traits traits
 List traits.
 
typedef base_class::gc gc
 Garbage collector used.
 
typedef base_class::back_off back_off
 Back-off strategy used.
 
typedef maker::data_allocator_type allocator_type
 Allocator type used for allocate/deallocate data.
 
typedef base_class::item_counter item_counter
 Item counting policy used.
 
typedef maker::key_comparator key_comparator
 key comparison functor
 
typedef base_class::memory_model memory_model
 Memory ordering. See cds::opt::memory_model option.
 
typedef base_class::stat stat
 Internal statistics.
 
typedef base_class::guarded_ptr guarded_ptr
 Guarded pointer.
 

Public Member Functions

 IterableKVList ()
 Default constructor. More...
 
 ~IterableKVList ()
 List destructor. More...
 
template<typename K >
bool insert (K &&key)
 Inserts new node with key and default value. More...
 
template<typename K , typename V >
bool insert (K &&key, V &&val)
 Inserts new node with a key and a value. More...
 
template<typename K , typename Func >
bool insert_with (K &&key, Func func)
 Inserts new node and initialize it by a functor. More...
 
template<typename K , typename Func >
std::pair< bool, bool > update (K &&key, Func f, bool bAllowInsert=true)
 Updates data by key. More...
 
template<typename Q , typename V >
std::pair< bool, bool > upsert (Q &&key, V &&val, bool bInsert=true)
 Insert or update. More...
 
template<typename K , typename... Args>
bool emplace (K &&key, Args &&... args)
 Inserts a new node using move semantics. More...
 
template<typename K >
bool erase (K const &key)
 Deletes key from the list. More...
 
template<typename K , typename Less >
bool erase_with (K const &key, Less pred)
 Deletes the item from the list using pred predicate for searching. More...
 
template<typename K , typename Func >
bool erase (K const &key, Func f)
 Deletes key from the list. More...
 
template<typename K , typename Less , typename Func >
bool erase_with (K const &key, Less pred, Func f)
 Deletes the item from the list using pred predicate for searching. More...
 
bool erase_at (iterator const &iter)
 Deletes the item pointed by iterator iter. More...
 
template<typename K >
guarded_ptr extract (K const &key)
 Extracts the item from the list with specified key. More...
 
template<typename K , typename Less >
guarded_ptr extract_with (K const &key, Less pred)
 Extracts the item from the list with comparing functor pred. More...
 
template<typename Q >
bool contains (Q const &key) const
 Checks whether the list contains key. More...
 
template<typename Q , typename Less >
bool contains (Q const &key, Less pred) const
 Checks whether the map contains key using pred predicate for searching. More...
 
template<typename Q , typename Func >
bool find (Q const &key, Func f) const
 Finds the key key and performs an action with it. More...
 
template<typename Q >
iterator find (Q const &key) const
 Finds key in the list and returns iterator pointed to the item found. More...
 
template<typename Q , typename Less , typename Func >
bool find_with (Q const &key, Less pred, Func f) const
 Finds the key val using pred predicate for searching. More...
 
template<typename Q , typename Less >
iterator find_with (Q const &key, Less pred) const
 Finds key in the list using pred predicate for searching and returns iterator pointed to the item found. More...
 
template<typename K >
guarded_ptr get (K const &key) const
 Finds the key and return the item found. More...
 
template<typename K , typename Less >
guarded_ptr get_with (K const &key, Less pred) const
 Finds the key and return the item found. More...
 
bool empty () const
 Checks if the list is empty. More...
 
size_t size () const
 Returns list's item count. More...
 
void clear ()
 Clears the list.
 
stat const & statistics () const
 Returns const reference to internal statistics.
 

Static Public Attributes

static constexpr const size_t c_nHazardPtrCount = base_class::c_nHazardPtrCount
 Count of hazard pointer required for the algorithm.
 

Additional Inherited Members

- Protected Types inherited from cds::container::IterableList< GC, std::pair< Key, Value >, Traits >
typedef std::pair< Key, Value > value_type
 Type of value stored in the list.
 
typedef Traits traits
 List traits.
 
typedef base_class::gc gc
 Garbage collector used.
 
typedef base_class::back_off back_off
 Back-off strategy used.
 
typedef maker::data_allocator_type allocator_type
 Allocator type used for allocate/deallocate data.
 
typedef base_class::item_counter item_counter
 Item counting policy used.
 
typedef maker::key_comparator key_comparator
 key comparison functor
 
typedef base_class::memory_model memory_model
 Memory ordering. See cds::opt::memory_model option.
 
typedef base_class::stat stat
 Internal statistics.
 
typedef base_class::guarded_ptr guarded_ptr
 Guarded pointer.
 
typedef iterator_type< false > iterator
 Forward iterator. More...
 
typedef iterator_type< true > const_iterator
 Const forward iterator. More...
 
- Protected Types inherited from cds::intrusive::IterableList< GC, std::pair< Key, Value >, Traits >
typedef std::pair< Key, Value > value_type
 type of value stored in the list
 
typedef Traits traits
 Traits template parameter.
 
typedef iterable_list::node< value_typenode_type
 node type
 
typedef implementation_defined key_comparator
 key comparison functor based on opt::compare and opt::less option setter.
 
typedef traits::disposer disposer
 disposer for value_type
 
typedef GC gc
 Garbage collector.
 
typedef traits::back_off back_off
 back-off strategy
 
typedef traits::item_counter item_counter
 Item counting policy used.
 
typedef traits::memory_model memory_model
 Memory ordering. See cds::opt::memory_model option.
 
typedef traits::node_allocator node_allocator
 Node allocator.
 
typedef traits::stat stat
 Internal statistics.
 
typedef gc::template guarded_ptr< value_typeguarded_ptr
 Guarded pointer.
 
typedef iterator_type< false > iterator
 Forward iterator. More...
 
typedef iterator_type< true > const_iterator
 Const forward iterator. More...
 
- Protected Member Functions inherited from cds::container::IterableList< GC, std::pair< Key, Value >, Traits >
 IterableList ()
 Default constructor. More...
 
 ~IterableList ()
 List destructor. More...
 
bool insert (Q &&val)
 Inserts new node. More...
 
bool insert (Q &&key, Func func)
 Inserts new node. More...
 
std::pair< bool, bool > update (Q &&key, Func func, bool bAllowInsert=true)
 Updates data by key. More...
 
std::pair< bool, bool > upsert (Q &&key, bool bInsert=true)
 Insert or update. More...
 
bool emplace (Args &&... args)
 Inserts data of type value_type constructed with std::forward<Args>(args)... More...
 
bool erase (Q const &key)
 Delete key from the list. More...
 
bool erase (Q const &key, Func f)
 Deletes key from the list. More...
 
bool erase_with (Q const &key, Less pred)
 Deletes the item from the list using pred predicate for searching. More...
 
bool erase_with (Q const &key, Less pred, Func f)
 Deletes the item from the list using pred predicate for searching. More...
 
bool erase_at (iterator const &iter)
 Deletes the item pointed by iterator iter. More...
 
guarded_ptr extract (Q const &key)
 Extracts the item from the list with specified key. More...
 
guarded_ptr extract_with (Q const &key, Less pred)
 Extracts the item from the list with comparing functor pred. More...
 
bool contains (Q const &key) const
 Checks whether the list contains key. More...
 
bool contains (Q const &key, Less pred) const
 Checks whether the list contains key using pred predicate for searching. More...
 
bool find (Q &key, Func f) const
 Finds key and perform an action with it. More...
 
iterator find (Q const &key) const
 Finds key in the list and returns iterator pointed to the item found. More...
 
bool find_with (Q &key, Less pred, Func f) const
 Finds key using pred predicate for searching. More...
 
iterator find_with (Q const &key, Less pred) const
 Finds key in the list using pred predicate for searching and returns iterator pointed to the item found. More...
 
guarded_ptr get (Q const &key) const
 Finds key and return the item found. More...
 
guarded_ptr get_with (Q const &key, Less pred) const
 Finds key and return the item found. More...
 
bool empty () const
 Checks if the list is empty. More...
 
size_t size () const
 Returns list's item count. More...
 
void clear ()
 Clears the list (thread safe, not atomic)
 
stat const & statistics () const
 Returns const reference to internal statistics.
 
iterator begin ()
 Returns a forward iterator addressing the first element in a list. More...
 
const_iterator begin () const
 Returns a forward const iterator addressing the first element in a list.
 
iterator end ()
 Returns an iterator that addresses the location succeeding the last element in a list. More...
 
const_iterator end () const
 Returns an const iterator that addresses the location succeeding the last element in a list.
 
const_iterator cbegin () const
 Returns a forward const iterator addressing the first element in a list.
 
const_iterator cend () const
 Returns an const iterator that addresses the location succeeding the last element in a list.
 
- Protected Member Functions inherited from cds::intrusive::IterableList< GC, std::pair< Key, Value >, Traits >
 IterableList ()
 Default constructor initializes empty list.
 
 ~IterableList ()
 Destroys the list object.
 
bool insert (value_type &val)
 Inserts new node. More...
 
bool insert (value_type &val, Func f)
 Inserts new node. More...
 
std::pair< bool, bool > update (value_type &val, Func func, bool bInsert=true)
 Updates the node. More...
 
std::pair< bool, bool > upsert (value_type &val, bool bInsert=true)
 Insert or update. More...
 
bool unlink (value_type &val)
 Unlinks the item val from the list. More...
 
bool erase (Q const &key)
 Deletes the item from the list. More...
 
bool erase (Q const &key, Func func)
 Deletes the item from the list. More...
 
bool erase_with (Q const &key, Less pred)
 Deletes the item from the list using pred predicate for searching. More...
 
bool erase_with (Q const &key, Less pred, Func f)
 Deletes the item from the list using pred predicate for searching. More...
 
bool erase_at (iterator const &iter)
 Deletes the item pointed by iterator iter. More...
 
guarded_ptr extract (Q const &key)
 Extracts the item from the list with specified key. More...
 
guarded_ptr extract_with (Q const &key, Less pred)
 Extracts the item using compare functor pred. More...
 
bool find (Q &key, Func f) const
 Finds key in the list. More...
 
iterator find (Q const &key) const
 Finds key in the list and returns iterator pointed to the item found. More...
 
bool find_with (Q &key, Less pred, Func f) const
 Finds the key using pred predicate for searching. More...
 
iterator find_with (Q const &key, Less pred) const
 Finds key in the list using pred predicate for searching and returns iterator pointed to the item found. More...
 
bool contains (Q const &key) const
 Checks whether the list contains key. More...
 
bool contains (Q const &key, Less pred) const
 Checks whether the list contains key using pred predicate for searching. More...
 
guarded_ptr get (Q const &key) const
 Finds the key and return the item found. More...
 
guarded_ptr get_with (Q const &key, Less pred) const
 Finds the key and return the item found. More...
 
void clear ()
 Clears the list (thread safe, not atomic)
 
bool empty () const
 Checks if the list is empty. More...
 
size_t size () const
 Returns list's item count. More...
 
stat const & statistics () const
 Returns const reference to internal statistics.
 
iterator begin ()
 Returns a forward iterator addressing the first element in a list. More...
 
const_iterator begin () const
 Returns a forward const iterator addressing the first element in a list.
 
iterator end ()
 Returns an iterator that addresses the location succeeding the last element in a list. More...
 
const_iterator end () const
 Returns an const iterator that addresses the location succeeding the last element in a list.
 
const_iterator cbegin () const
 Returns a forward const iterator addressing the first element in a list.
 
const_iterator cend () const
 Returns an const iterator that addresses the location succeeding the last element in a list.
 
- Static Protected Attributes inherited from cds::container::IterableList< GC, std::pair< Key, Value >, Traits >
static constexpr const size_t c_nHazardPtrCount
 Count of hazard pointer required for the algorithm.
 
- Static Protected Attributes inherited from cds::intrusive::IterableList< GC, std::pair< Key, Value >, Traits >
static constexpr const size_t c_nHazardPtrCount
 Count of hazard pointer required for the algorithm.
 

Detailed Description

template<typename GC, typename Key, typename Value, typename Traits = iterable_list::traits>
class cds::container::IterableKVList< GC, Key, Value, Traits >

Iterable ordered list for key-value pair.

This is key-value variation of non-intrusive IterableList. Like standard container, this implementation split a value stored into two part - constant key and alterable value.

Usually, ordered single-linked list is used as a building block for the hash table implementation. Iterable list is suitable for almost append-only hash table because the list doesn't delete its internal node when erasing a key but it is marked them as empty to be reused in the future. However, plenty of empty nodes degrades performance.

The complexity of searching is O(N).

Template arguments:

  • GC - garbage collector used
  • Key - key type of an item stored in the list. It should be copy-constructible
  • Value - value type stored in a list
  • Traits - type traits, default is iterable_list::traits

It is possible to declare option-based list with cds::container::iterable_list::make_traits metafunction instead of Traits template argument. For example, the following traits-based declaration of gc::HP iterable list

#include <cds/container/iterable_kvlist_hp.h>
// Declare comparator for the item
struct my_compare {
int operator ()( int i1, int i2 )
{
return i1 - i2;
}
};
// Declare traits
struct my_traits: public cds::container::iterable_list::traits
{
typedef my_compare compare;
};
// Declare traits-based list

is equivalent for the following option-based list

#include <cds/container/iterable_kvlist_hp.h>
// my_compare is the same
// Declare option-based list
>::type
> option_based_list;
Usage
There are different specializations of this template for each garbage collecting schema used. You should include appropriate .h-file depending on GC you are using:
  • for gc::HP:
    #include <cds/container/iterable_kvlist_hp.h>
  • for gc::DHP:
    #include <cds/container/iterable_kvlist_dhp.h>
  • for RCU:
    #include <cds/container/iterable_kvlist_rcu.h>

Constructor & Destructor Documentation

◆ IterableKVList()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
cds::container::IterableKVList< GC, Key, Value, Traits >::IterableKVList ( )
inline

Default constructor.

Initializes empty list

◆ ~IterableKVList()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
cds::container::IterableKVList< GC, Key, Value, Traits >::~IterableKVList ( )
inline

List destructor.

Clears the list

Member Function Documentation

◆ contains() [1/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename Q >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::contains ( Q const &  key) const
inline

Checks whether the list contains key.

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

◆ contains() [2/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename Q , typename Less >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::contains ( Q const &  key,
Less  pred 
) const
inline

Checks whether the map 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 list.

◆ emplace()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K , typename... Args>
bool cds::container::IterableKVList< GC, Key, Value, Traits >::emplace ( K &&  key,
Args &&...  args 
)
inline

Inserts a new node using move semantics.

key_type field of new item is constructed from key argument, mapped_type field is done from args.

Returns true if inserting successful, false otherwise.

◆ empty()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
bool cds::container::IterableKVList< GC, Key, Value, Traits >::empty ( ) const
inline

Checks if the list is empty.

Emptiness is checked by item counting: if item count is zero then the set is empty. Thus, if you need to use empty() you should provide appropriate (non-empty) iterable_list::traits::item_counter feature.

◆ erase() [1/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::erase ( K const &  key)
inline

Deletes key from the list.

Returns true if key is found and has been deleted, false otherwise

◆ erase() [2/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K , typename Func >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::erase ( K const &  key,
Func  f 
)
inline

Deletes key from the list.

The function searches an item with key key, calls f functor and deletes the item. If key is not found, the functor is not called.

The functor Func interface:

struct extractor {
void operator()(value_type& val) { ... }
};

Return true if key is found and deleted, false otherwise

◆ erase_at()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
bool cds::container::IterableKVList< GC, Key, Value, Traits >::erase_at ( iterator const &  iter)
inline

Deletes the item pointed by iterator iter.

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.

◆ erase_with() [1/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K , typename Less >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::erase_with ( K const &  key,
Less  pred 
)
inline

Deletes the item from the list using pred predicate for searching.

The function is an analog of erase(K const&) 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 list.

◆ erase_with() [2/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K , typename Less , typename Func >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::erase_with ( K const &  key,
Less  pred,
Func  f 
)
inline

Deletes the item from the list using pred predicate for searching.

The function is an analog of erase(K const&, Func) 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 list.

◆ extract()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K >
guarded_ptr cds::container::IterableKVList< GC, Key, Value, Traits >::extract ( K const &  key)
inline

Extracts the item from the list with specified key.

The function searches an item with key equal to key, unlinks it from the list, 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 K that can be not the same as key_type.

The disposer specified in Traits class template parameter is called automatically by garbage collector GC specified in class' template parameters 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:

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

◆ extract_with()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K , typename Less >
guarded_ptr cds::container::IterableKVList< GC, Key, Value, Traits >::extract_with ( K const &  key,
Less  pred 
)
inline

Extracts the item from the list with comparing functor pred.

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

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

◆ find() [1/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename Q , typename Func >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::find ( Q const &  key,
Func  f 
) const
inline

Finds the key key and performs an action with it.

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

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

where item is the item found.

The functor may change item.second that is reference to value of node. Note that the function is only guarantee that item cannot be deleted during functor is executing. The function does not serialize simultaneous access to the list item. If such access is possible you must provide your own synchronization schema to exclude unsafe item modifications.

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

◆ find() [2/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename Q >
iterator cds::container::IterableKVList< GC, Key, Value, Traits >::find ( Q const &  key) const
inline

Finds key in the list and returns iterator pointed to the item found.

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

◆ find_with() [1/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename Q , typename Less , typename Func >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::find_with ( Q const &  key,
Less  pred,
Func  f 
) const
inline

Finds the key val using pred predicate for searching.

The function is an analog of find(Q&, Func) 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 list.

◆ find_with() [2/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename Q , typename Less >
iterator cds::container::IterableKVList< GC, Key, Value, Traits >::find_with ( Q const &  key,
Less  pred 
) const
inline

Finds key in the list using pred predicate for searching and returns iterator pointed to the item found.

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 list.

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

◆ get()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K >
guarded_ptr cds::container::IterableKVList< GC, Key, Value, Traits >::get ( K const &  key) const
inline

Finds the key and return the item found.

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

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

Usage:

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

Note the compare functor specified for class Traits template parameter should accept a parameter of type K that can be not the same as key_type.

◆ get_with()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K , typename Less >
guarded_ptr cds::container::IterableKVList< GC, Key, Value, Traits >::get_with ( K const &  key,
Less  pred 
) const
inline

Finds the key and return the item found.

The function is an analog of get( guarded_ptr& ptr, K const&) but pred is used for comparing the keys.

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

◆ insert() [1/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::insert ( K &&  key)
inline

Inserts new node with key and default value.

The function creates a node with key and default value, and then inserts the node created into the list.

Preconditions:

  • The key_type should be constructible from value of type K. In trivial case, K is equal to key_type.
  • The mapped_type should be default-constructible.

Returns true if inserting successful, false otherwise.

Note
The function is supported only if mapped_type is default constructible

◆ insert() [2/2]

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K , typename V >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::insert ( K &&  key,
V &&  val 
)
inline

Inserts new node with a key and a value.

The function creates a node with key and value val, and then inserts the node created into the list.

Preconditions:

  • The key_type should be constructible from key of type K.
  • The mapped_type should be constructible from val of type V.

Returns true if inserting successful, false otherwise.

◆ insert_with()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K , typename Func >
bool cds::container::IterableKVList< GC, Key, Value, Traits >::insert_with ( K &&  key,
Func  func 
)
inline

Inserts new node and initialize it by a functor.

This function inserts new node with key key and if inserting is successful then it calls func functor with signature

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

The argument item of user-defined functor func is the reference to the item inserted. item.second is a reference to item's value that may be changed. User-defined functor func should guarantee that during changing item's value no any other changes could be made on this list's item by concurrent threads. The user-defined functor is called only if inserting is successful.

The key_type should be constructible from value of type K.

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

  • create a new item from key;
  • insert the new item into the list;
  • if inserting is successful, initialize the value of item by calling func functor

This can be useful if complete initialization of object of mapped_type is heavyweight and it is preferable that the initialization should be completed only if inserting is successful.

Warning
See insert item troubleshooting
Note
The function is supported only if mapped_type is default constructible

◆ size()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
size_t cds::container::IterableKVList< GC, Key, Value, Traits >::size ( ) const
inline

Returns list's item count.

The value returned depends on item counter provided by Traits. For atomicity::empty_item_counter, this function always returns 0.

◆ update()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename K , typename Func >
std::pair<bool, bool> cds::container::IterableKVList< GC, Key, Value, Traits >::update ( K &&  key,
Func  f,
bool  bAllowInsert = true 
)
inline

Updates data by key.

The operation performs inserting or replacing the element with lock-free manner.

If the key not found in the list, then the new item created from key will be inserted iff bAllowInsert is true. (note that in this case the key_type should be constructible from type K). Otherwise, if key is found, the functor func is called with item found.

The functor func is called after inserting or replacing, it signature is:

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

where

  • val - a new data constructed from key
  • old - old value that will be retired. If new item has been inserted then old is nullptr.

The functor may change non-key fields of val; however, func must guarantee that during changing no any other modifications could be made on this item by concurrent threads.

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 such key already exists.
Warning
See insert item troubleshooting
Note
The function is supported only if mapped_type is default constructible

◆ upsert()

template<typename GC , typename Key , typename Value , typename Traits = iterable_list::traits>
template<typename Q , typename V >
std::pair<bool, bool> cds::container::IterableKVList< GC, Key, Value, Traits >::upsert ( Q &&  key,
V &&  val,
bool  bInsert = true 
)
inline

Insert or update.

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

If the item key is not found in the list, then key is inserted iff bInsert is true. Otherwise, the current element is changed to value_type( key, val ), the old element will be retired later.

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


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

cds 2.3.1 Developed by Maxim Khizhinsky aka khizmax 2007 - 2017
Autogenerated Fri Sep 1 2017 08:47:00 by Doxygen 1.8.13