mostly_harmless::data Namespace Reference

Contains classes and functions related to data management. More...

Classes
class	DatabasePropertyWatcher
	A convenience class for responding to changes in a databaseState, potentially fired from other processes. Watches a given property's field corresponding to type T for changes, and fires a callback on change. Note that callback will run on a background timer thread, so if you need thread safety, be sure to utilise ISharedState::callOnMessageThread from your callback lambda. More...

Typedefs
using	DatabaseValueVariant = std::variant<std::string, bool, int, float, double>
	A std::variant containing all types satisfying the DatabaseStorageType concept.

Functions
	DatabaseState (const DatabaseState &)=delete
	DatabaseState (DatabaseState &&other) noexcept
DatabaseState &	operator= (const DatabaseState &)=delete
DatabaseState &	operator= (DatabaseState &&other) noexcept
static auto	tryCreate (const std::filesystem::path &location, const std::vector< std::pair< std::string, DatabaseValueVariant > > &initialValues) -> std::optional< DatabaseState >
	~DatabaseState () noexcept
template<DatabaseStorageType T>
auto	set (std::string_view name, const T &toSet) -> void
template<DatabaseStorageType T>
auto	get (std::string_view name) -> std::optional< T >
auto	duplicate () const -> std::optional< DatabaseState >

Detailed Description

Contains classes and functions related to data management.

Typedef Documentation

DatabaseValueVariant

using mostly_harmless::data::DatabaseValueVariant = std::variant<std::string, bool, int, float, double>

A std::variant containing all types satisfying the DatabaseStorageType concept.

Function Documentation

DatabaseState() [1/2]

mostly_harmless::data::DatabaseState ( const DatabaseState & )

delete

Non Copyable, as the database connection pointer will be closed on destruction...

DatabaseState() [2/2]

mostly_harmless::data::DatabaseState ( DatabaseState && other )

noexcept

Moveable, nulls other's connection pointer

Parameters

other

The moved-from DatabaseState instance

duplicate()

auto mostly_harmless::data::duplicate ( ) const -> std::optional< DatabaseState >

nodiscard

Tries to create a copy of the current database connection. This is useful as database connections are only safe to use on a single thread - so for polling for changes on a background thread for example, a new connection must be used.

Will not work with an in-memory database created with filename = ":memory:".

Returns

A copy of the current connection if succeeded, nullopt otherwise.

get()

template<DatabaseStorageType T>

auto mostly_harmless::data::get ( std::string_view name ) -> std::optional< T >

nodiscard

Attempts to retrieve the value of a named field in the database.

Template Parameters

T	A std::string, bool, any int, float, or double.

Parameters

name	The name of the database field to retrieve

Returns

The value of the retrieved database field if found, nullopt otherwise.

operator=() [1/2]

DatabaseState & mostly_harmless::data::operator= ( const DatabaseState & )

delete

Non Copyable, as the database connection pointer will be closed on destruction...

operator=() [2/2]

DatabaseState & mostly_harmless::data::operator= ( DatabaseState && other )

noexcept

Moveable, nulls other's connection pointer

Parameters

other

The moved-from DatabaseState instance

Returns

*this

set()

template<DatabaseStorageType T>

auto mostly_harmless::data::set	(	std::string_view	name,
		const T &	toSet ) -> void

Sets the value of a database entry with a matching name. If not found, will first create the entry.

Template Parameters

T	A std::string, bool, any int, float, or double

Parameters

name	The name of the field to set.
toSet	The value to set.

tryCreate()

auto mostly_harmless::data::tryCreate ( const std::filesystem::path & location, const std::vector< std::pair< std::string, DatabaseValueVariant > > & initialValues ) -> std::optional< DatabaseState >

staticnodiscard

Attempts to create a new DatabaseState instance. On construction, will attempt to open the database passed to location, and establish a connection to it if it exists. If it doesn't exist, creates the database, and a table to store user data in.

Parameters

location	A path to the database to create or open.
initialValues	A vector containing the initial values to add to the database if it didn't exist. If the database DID exist, but any of the keys in the vector aren't present, they'll be added with the values specified and existing items will be skipped.

Returns

A DatabaseState instance on success, nullopt otherwise.

~DatabaseState()

mostly_harmless::data::~DatabaseState ( )

noexcept

The internal database handle is closed if not null.