temptable::Key_value_store< Lock, KeyValueImpl > Class Template Reference

Key-value store, a convenience wrapper class which models a thread-safe dictionary type. More...

#include <kv_store.h>

Inheritance diagram for temptable::Key_value_store< Lock, KeyValueImpl >:

Public Member Functions
template<class... Args>
std::pair< typename Key_value_store_impl::iterator, bool >	emplace (Args &&...args)
	Inserts a new table into the container constructed in-place with the given args if there is no table with the key in the container. More...
Table *	find (const std::string &key)
	Searches for a table with given name (key). More...
Key_value_store_impl::size_type	erase (const std::string &key)
	Removes the table (if one exists) with the given name (key). More...

Private Types
using	Exclusive_or_shared_lock = std::conditional_t< std::is_same< Lock, std::shared_timed_mutex >::value, std::shared_lock< Lock >, std::lock_guard< Lock > >
	Check whether we can use shared locks (which enable multiple concurrent readers) or must we rather fallback to exclusive locks. More...
using	Key_value_store_impl = KeyValueImpl< std::string, Table >
	Alias for our key-value store implementation. More...

Private Attributes
Key_value_store_impl	m_kv_store
	Container holding (table-name, Table) tuples. More...
Lock	m_lock
	Lock type. More...

Friends
class	Key_value_store_logger< Key_value_store< Lock, KeyValueImpl >, DEBUG_BUILD >
	Do not break encapsulation when using CRTP. More...

Additional Inherited Members
Protected Member Functions inherited from temptable::Key_value_store_logger< Key_value_store< Lock, std::unordered_map >, DEBUG_BUILD >
void	log (Key_value_store_stats::Event)
void	dbug_print ()

Detailed Description

template<typename Lock, template< typename... > class KeyValueImpl = std::unordered_map>
class temptable::Key_value_store< Lock, KeyValueImpl >

Key-value store, a convenience wrapper class which models a thread-safe dictionary type.

Thread-safety is accomplished by using a Lock which can be any of the usual mutual exclusive algorithms from C++ thread-support library or any other which satisfy C++ concurrency named requirements. E.g. mutex, timed_mutex, recursive_mutex, recursive_timed_mutex, shared_mutex, shared_timed_mutex, ... User code can opt-in for any of those. Also, whether the actual implementation will use shared-locks or exclusive-locks (for read-only operations) is handled automagically by this class.

Furthermore, user code can similarly opt-in for different key-value implementation but whose interface is compatible with the one of std::unordered_map.

Member Typedef Documentation

Exclusive_or_shared_lock

template<typename Lock , template< typename... > class KeyValueImpl = std::unordered_map>

using temptable::Key_value_store< Lock, KeyValueImpl >::Exclusive_or_shared_lock = std::conditional_t<std::is_same<Lock, std::shared_timed_mutex>::value, std::shared_lock<Lock>, std::lock_guard<Lock> >

private

Check whether we can use shared locks (which enable multiple concurrent readers) or must we rather fallback to exclusive locks.

Shared-locks will be used only during read-only operations.

Key_value_store_impl

template<typename Lock , template< typename... > class KeyValueImpl = std::unordered_map>

using temptable::Key_value_store< Lock, KeyValueImpl >::Key_value_store_impl = KeyValueImpl<std::string, Table>

private

Alias for our key-value store implementation.

Member Function Documentation

emplace()

template<typename Lock , template< typename... > class KeyValueImpl = std::unordered_map>

template<class... Args>

std::pair< typename Key_value_store_impl::iterator, bool > temptable::Key_value_store< Lock, KeyValueImpl >::emplace ( Args &&...  args )

inline

Inserts a new table into the container constructed in-place with the given args if there is no table with the key in the container.

[in] args Arguments to forward to the constructor of the table.

Returns

Returns a pair consisting of an iterator to the inserted table, or the already-existing table if no insertion happened, and a bool denoting whether the insertion took place (true if insertion happened, false if it did not).

erase()

template<typename Lock , template< typename... > class KeyValueImpl = std::unordered_map>

Key_value_store_impl::size_type temptable::Key_value_store< Lock, KeyValueImpl >::erase ( const std::string &  key )

inline

Removes the table (if one exists) with the given name (key).

[in] key Name of a table to remove..

Returns

Number of elements removed.

find()

template<typename Lock , template< typename... > class KeyValueImpl = std::unordered_map>

Table * temptable::Key_value_store< Lock, KeyValueImpl >::find ( const std::string &  key )

inline

Searches for a table with given name (key).

[in] key Name of a table to search for.

Returns

Pointer to table if found, nullptr otherwise.

Friends And Related Function Documentation

Key_value_store_logger< Key_value_store< Lock, KeyValueImpl >, DEBUG_BUILD >

template<typename Lock , template< typename... > class KeyValueImpl = std::unordered_map>

friend class Key_value_store_logger< Key_value_store< Lock, KeyValueImpl >, DEBUG_BUILD >

friend

Do not break encapsulation when using CRTP.

Member Data Documentation

m_kv_store

template<typename Lock , template< typename... > class KeyValueImpl = std::unordered_map>

Key_value_store_impl temptable::Key_value_store< Lock, KeyValueImpl >::m_kv_store

private

Container holding (table-name, Table) tuples.

m_lock

template<typename Lock , template< typename... > class KeyValueImpl = std::unordered_map>

Lock temptable::Key_value_store< Lock, KeyValueImpl >::m_lock

private

Lock type.

---

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

• storage/temptable/include/temptable/kv_store.h