mostly_harmless::data::DatabasePropertyWatcher< T > Class Template Reference

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...

#include <mostlyharmless_DatabasePropertyWatcher.h>

Public Member Functions
	DatabasePropertyWatcher (const DatabasePropertyWatcher &)=delete
	DatabasePropertyWatcher (DatabasePropertyWatcher &&) noexcept=delete
auto	operator= (const DatabasePropertyWatcher &) -> DatabasePropertyWatcher=delete
auto	operator= (DatabasePropertyWatcher &&) noexcept -> DatabasePropertyWatcher=delete

Static Public Member Functions
static auto	tryCreate (const DatabaseState &databaseState, std::string_view propertyName, int pollFrequencyMs, std::function< void(const T &)> &&callback) -> std::unique_ptr< DatabasePropertyWatcher >

Detailed Description

template<DatabaseStorageType T>
class mostly_harmless::data::DatabasePropertyWatcher< T >

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.

Template Parameters

T	Any type satisfying DatabaseStorageType

Constructor & Destructor Documentation

DatabasePropertyWatcher() [1/2]

template<DatabaseStorageType T>

mostly_harmless::data::DatabasePropertyWatcher< T >::DatabasePropertyWatcher ( const DatabasePropertyWatcher< T > & )

delete

Non copyable

DatabasePropertyWatcher() [2/2]

template<DatabaseStorageType T>

mostly_harmless::data::DatabasePropertyWatcher< T >::DatabasePropertyWatcher ( DatabasePropertyWatcher< T > && )

deletenoexcept

Non moveable

Member Function Documentation

operator=() [1/2]

template<DatabaseStorageType T>

auto mostly_harmless::data::DatabasePropertyWatcher< T >::operator= ( const DatabasePropertyWatcher< T > & ) -> DatabasePropertyWatcher=delete

delete

Non copyable

operator=() [2/2]

template<DatabaseStorageType T>

auto mostly_harmless::data::DatabasePropertyWatcher< T >::operator= ( DatabasePropertyWatcher< T > && ) -> DatabasePropertyWatcher=delete

deletenoexcept

Non moveable

tryCreate()

template<DatabaseStorageType T>

auto mostly_harmless::data::DatabasePropertyWatcher< T >::tryCreate ( const DatabaseState & databaseState, std::string_view propertyName, int pollFrequencyMs, std::function< void(const T &)> && callback ) -> std::unique_ptr< DatabasePropertyWatcher >

inlinestatic

Attempts to create a DatabasePropertyWatcher for the given property name. As sqlite requires database access across different processes to each have their own unique connection, we first call DatabaseState::duplicate to create a new connection specifically for this thread.

Parameters

databaseState	A const reference to the database connection to duplicate for this PropertyWatcher.
propertyName	The name of the property to watch.
pollFrequencyMs	The interval in milliseconds to poll the database for changes at.
callback	A lambda to be invoked from a background timer thread on property value change.

Returns

A DatabasePropertyWatcher for the given property name if successful, nullptr otherwise.

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

• /home/runner/work/mostly-harmless/mostly-harmless/include/mostly_harmless/data/mostlyharmless_DatabasePropertyWatcher.h