Struct zng::config::FallbackConfig

pub struct FallbackConfig<S, F>(/* private fields */)
where
    S: Config,
    F: Config;

Represents a copy-on-write config source that wraps two other sources, a read-write config and a read-only fallback config.

The config variables are connected to both sources, if the read-write config is not set the var will update with the fallback config, if it is set it will sync with the read-write config.

The FallbackConfig type is an Arc internally, so you can keep a cloned reference to it after moving it into CONFIG or another combinator config.

Implementations

impl<S, F> FallbackConfig<S, F>

where S: Config, F: Config,

pub fn new(config: S, fallback: F) -> FallbackConfig<S, F>

New from the read-write config and read-only fallback.

pub fn reset(&self, key: &Txt)

Removes the key from the config and updates all active config variables back to the fallback value. Note that if you assign the config variable the key will be re-inserted on the config.

pub fn can_reset(&self, key: Txt) -> Box<dyn VarBoxed<bool>>

Returns a read-only var that is true when the key has an entry in the read-write config.

Trait Implementations

impl<S, F> AnyConfig for FallbackConfig<S, F>

where S: Config, F: Config,

fn status(&self) -> Box<dyn VarBoxed<ConfigStatus>>

Gets a read-only variable that represents the IO status of the config.

fn get_raw( &mut self, key: Txt, default: RawConfigValue, insert: bool, shared: bool, ) -> Box<dyn VarBoxed<RawConfigValue>>

Gets a weak typed variable to the config key.

fn contains_key(&mut self, key: Txt) -> Box<dyn VarBoxed<bool>>

Gets a read-only variable that tracks if an entry for the key is in the backing storage.

fn remove(&mut self, key: &Txt) -> bool

Removes the key from the backing storage.

fn low_memory(&mut self)

Cleanup and flush RAM caches.

impl<S, F> Clone for FallbackConfig<S, F>

where S: Config, F: Config,

fn clone(&self) -> FallbackConfig<S, F>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<S, F> Config for FallbackConfig<S, F>

where S: Config, F: Config,

fn get<T>( &mut self, key: impl Into<Txt>, default: T, insert: bool, ) -> Box<dyn VarBoxed<T>>

where T: ConfigValue,

Gets a variable that is bound to the config key.

impl<S, F> FallbackConfigReset for FallbackConfig<S, F>

where S: Config, F: Config,

fn reset(&self, key: &Txt)

Removes the key from the config and updates all active config variables back to the fallback value. Note that if you assign the config variable the key will be re-inserted on the config.

fn can_reset(&self, key: Txt) -> Box<dyn VarBoxed<bool>>

Returns a read-only var that is true when the key has an entry in the read-write config.

fn clone_boxed(&self) -> Box<dyn FallbackConfigReset>

Clone a reference to the config.