cds  2.3.1
cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits > Class Template Reference

Lazy ordered list (key-value pair), template specialization for RCU. More...

#include <cds/container/lazy_kvlist_rcu.h>

Inheritance diagram for cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >:
cds::intrusive::LazyList< cds::urcu::gc< RCU >, implementation_defined, Traits >

Public Types

typedef cds::urcu::gc< RCU > gc
 Garbage collector.
 
typedef Traits traits
 List traits.
 
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 base_class::back_off back_off
 Back-off strategy used.
 
typedef maker::allocator_type allocator_type
 Allocator type used for allocate/deallocate the nodes.
 
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::rcu_check_deadlock rcu_check_deadlock
 RCU deadlock checking policy.
 
typedef gc::scoped_lock rcu_lock
 RCU scoped lock.
 
using exempt_ptr = cds::urcu::exempt_ptr< gc, node_type, value_type, typename maker::intrusive_traits::disposer, cds::urcu::details::conventional_exempt_pair_cast< node_type, value_type > >
 pointer to extracted node
 
typedef value_typeraw_ptr
 Type of get() member function return value.
 

Public Member Functions

 LazyKVList ()
 Default constructor.
 
 ~LazyKVList ()
 Destructor clears the list.
 
template<typename K >
bool insert (const K &key)
 Inserts new node with key and default value. More...
 
template<typename K , typename V >
bool insert (const K &key, const V &val)
 Inserts new node with a key and a value. More...
 
template<typename K , typename Func >
bool insert_with (const K &key, Func func)
 Inserts new node and initializes it by a functor. More...
 
template<typename... Args>
bool emplace (Args &&... args)
 Inserts data of type mapped_type constructed from args. More...
 
template<typename K , typename Func >
std::pair< bool, bool > update (const K &key, Func func, bool bAllowInsert=true)
 Updates data by key. 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...
 
template<typename K >
exempt_ptr extract (K const &key)
 Extracts an item from the list. More...
 
template<typename K , typename Less >
exempt_ptr extract_with (K const &key, Less pred)
 Extracts an item from the list using pred predicate for searching. 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 , 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 K >
value_typeget (K const &key) const
 Finds key and return the item found. More...
 
template<typename K , typename Less >
value_typeget_with (K const &key, Less pred) const
 Finds key and return the item found. More...
 
bool empty () const
 Checks if the list is empty.
 
size_t size () const
 Returns list's item count. More...
 
stat const & statistics () const
 Returns const reference to internal statistics.
 
void clear ()
 Clears the list.
 

Static Public Attributes

static constexpr const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal
 Group of extract_xxx functions require external locking.
 

Forward iterators

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

Additional Inherited Members

- Protected Types inherited from cds::intrusive::LazyList< cds::urcu::gc< RCU >, implementation_defined, Traits >
typedef node_type::marked_ptr marked_node_ptr
 Node marked pointer.
 
typedef node_typeauxiliary_head
 Auxiliary head type (for split-list support)
 
typedef cds::urcu::gc< RCU > gc
 Garbage collector.
 
typedef implementation_defined value_type
 type of value stored in the list
 
typedef Traits traits
 Traits template parameter.
 
typedef traits::hook hook
 hook type
 
typedef hook::node_type node_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
 
typedef get_node_traits< value_type, node_type, hook >::type node_traits
 node traits
 
typedef lazy_list::get_link_checker< node_type, traits::link_checker >::type link_checker
 link checker
 
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
 C++ memory ordering (see lazy_list::traits::memory_model)
 
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::intrusive::LazyList< cds::urcu::gc< RCU >, implementation_defined, Traits >
 LazyList ()
 Default constructor initializes empty list.
 
 ~LazyList ()
 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 bAllowInsert=true)
 Updates the item. 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 (const Q &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 (const Q &key, Less pred, Func func)
 Deletes the item from the list using pred predicate for searching. 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 find (Q &key, Func f)
 Finds the key key. More...
 
bool find_with (Q &key, Less pred, Func f)
 Finds the key key using pred predicate for searching. More...
 
bool contains (Q const &key)
 Checks whether the list contains key. More...
 
guarded_ptr get (Q const &key)
 
guarded_ptr get_with (Q const &key, Less pred)
 Finds key and return the item found. More...
 
void clear ()
 Clears the list.
 
bool empty () const
 Checks if the list is empty.
 
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::intrusive::LazyList< cds::urcu::gc< RCU >, implementation_defined, Traits >
static constexpr const size_t c_nHazardPtrCount
 Count of hazard pointer required for the algorithm.
 

Detailed Description

template<typename RCU, typename Key, typename Value, typename Traits = lazy_list::traits>
class cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >

Lazy ordered list (key-value pair), template specialization for RCU.

This is key-value variation of non-intrusive LazyList. 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. The complexity of searching is O(N).

Template arguments:

  • RCU - one of RCU type
  • Key - key type of an item to be stored in the list. It should be copy-constructible
  • Value - value type to be stored in the list
  • Traits - type traits, default is lazy_list::traits It is possible to declare option-based list with lazy_list::make_traits metafunction istead of Traits template argument. For example, the following traits-based declaration of gc::HP lazy list
    #include <cds/urcu/general_threaded.h>
    #include <cds/container/lazy_kvlist_rcu.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::lazy_list::traits
    {
    typedef my_compare compare;
    };
    // Declare traits-based list
    typedef cds::container::LazyKVList< cds::urcu::gc< cds::urcu::general_threaded<> >, int, int, my_traits > traits_based_list;
    is equal to the following option-based list
    #include <cds/urcu/general_threaded.h>
    #include <cds/container/lazy_kvlist_rcu.h>
    // my_compare is the same
    // Declare option-based list
    typedef cds::container::LazyKVList< cds::urcu::gc< cds::urcu::general_threaded<> >, int, int,
    >::type
    > option_based_list;
Note
Before including <cds/container/lazy_kvlist_rcu.h> you should include appropriate RCU header file, see RCU type for list of existing RCU class and corresponding header files.

Member Typedef Documentation

◆ iterator

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
typedef iterator_type<false> cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::iterator

Forward iterator.

You may safely use iterators in multi-threaded environment only under external RCU lock. Otherwise, a program crash is possible if another thread deletes the item the iterator points to.

Member Function Documentation

◆ begin()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
iterator cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::begin ( )
inline

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

For empty list

begin() == end()

◆ contains() [1/2]

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename Q >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, 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.

The function applies RCU lock internally.

◆ contains() [2/2]

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename Q , typename Less >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, 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.

The function applies RCU lock internally.

◆ emplace()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename... Args>
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::emplace ( Args &&...  args)
inline

Inserts data of type mapped_type constructed from args.

Returns true if inserting successful, false otherwise.

The function makes RCU lock internally.

◆ end()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
iterator cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::end ( )
inline

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

Do not use the value returned by end function to access any item. Internally, end returning value pointing to dummy tail node.

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

begin() == end()

◆ erase() [1/2]

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::erase ( K const &  key)
inline

Deletes key from the list.

RCU synchronize method can be called. RCU should not be locked.

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

◆ erase() [2/2]

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K , typename Func >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, 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) { ... }
};

RCU synchronize method can be called. RCU should not be locked.

Returns true if key is found and deleted, false otherwise

◆ erase_with() [1/2]

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K , typename Less >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, 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 RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K , typename Less , typename Func >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, 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 RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K >
exempt_ptr cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::extract ( K const &  key)
inline

Extracts an item from the list.

The function searches an item with key equal to key in the list, unlinks it from the list, and returns exempt_ptr pointer to the item found. If key is not found the function returns an empty 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 list and returns a pointer to item found. You should manually lock RCU before calling this function.
#include <cds/urcu/general_buffered.h>
#include <cds/container/lazy_kvlist_rcu.h>
typedef cds::urcu::gc< general_buffered<> > rcu;
rcu_lazy_list theList;
// ...
rcu_lazy_list::exempt_ptr p;
{
// first, we should lock RCU
rcu_lazy_list::rcu_lock sl;
// Now, you can apply extract function
// Note that you must not delete the item found inside the RCU lock
p = theList.extract( 10 );
if ( !p ) {
// do something with p
...
}
}
// Outside RCU lock section we may safely release extracted pointer.
// release() passes the pointer to RCU reclamation cycle.
p.release();

◆ extract_with()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K , typename Less >
exempt_ptr cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::extract_with ( K const &  key,
Less  pred 
)
inline

Extracts an item from the list using pred predicate for searching.

This function is the analog for extract(K const&). The pred is a predicate used for key comparing. Less has the interface like std::less. pred must imply the same element order as key_comparator.

◆ find()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename Q , typename Func >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, 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 applies RCU lock internally.

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

◆ find_with()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename Q , typename Less , typename Func >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, 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 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.

◆ get()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K >
value_type* cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::get ( K const &  key) const
inline

Finds key and return the item found.

The function searches the item with key and returns the pointer to item found. If key is not found it returns nullptr.

Note the compare functor should accept a parameter of type K that can be not the same as key_type.

RCU should be locked before call of this function. Returned item is valid only while RCU is locked:

ord_list theList;
// ...
{
// Lock RCU
ord_list::rcu_lock lock;
ord_list::value_type * pVal = theList.get( 5 );
if ( pVal ) {
// Deal with pVal
//...
}
// Unlock RCU by rcu_lock destructor
// pVal can be freed at any time after RCU has been unlocked
}

◆ get_with()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K , typename Less >
value_type* cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::get_with ( K const &  key,
Less  pred 
) const
inline

Finds key and return the item found.

The function is an analog of get(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 RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::insert ( const 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.

The function makes RCU lock internally.

Returns true if inserting successful, false otherwise.

◆ insert() [2/2]

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K , typename V >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::insert ( const K &  key,
const 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.

The function makes RCU lock internally.

Returns true if inserting successful, false otherwise.

◆ insert_with()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K , typename Func >
bool cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::insert_with ( const K &  key,
Func  func 
)
inline

Inserts new node and initializes 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 list's item inserted. item.second is a reference to item's value that may be changed. 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 item from key;
  • insert 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.

The function makes RCU lock internally.

Warning
See insert item troubleshooting

◆ size()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
size_t cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::size ( ) const
inline

Returns list's item count.

The value returned depends on opt::item_counter option. For atomicity::empty_item_counter, this function always returns 0.

Note
Even if you use real item counter and it returns 0, this fact is not mean that the list is empty. To check list emptyness use empty() method.

◆ update()

template<typename RCU , typename Key , typename Value , typename Traits = lazy_list::traits>
template<typename K , typename Func >
std::pair<bool, bool> cds::container::LazyKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::update ( const K &  key,
Func  func,
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 signature is:

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

with arguments:

  • bNew - true if the item has been inserted, false otherwise
  • item - the item found or inserted

The functor may change any fields of the item.second of mapped_type; during func call item is locked so it is safe to modify the item in multi-threaded environment.

The function applies RCU lock internally.

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 key already exists.


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 08:47:01 by Doxygen 1.8.13