Trait PreferencesStore 

pub trait PreferencesStore: Send + Sync {
    // Required methods
    fn get(&self, key: &str) -> Option<String>;
    fn set(&self, key: &str, value: &str) -> Result<(), PreferencesError>;
    fn remove(&self, key: &str) -> Result<(), PreferencesError>;
    fn keys(&self) -> Vec<String>;
    fn clear(&self) -> Result<(), PreferencesError>;

    // Provided methods
    fn set_many(
        &self,
        values: &BTreeMap<String, String>,
    ) -> Result<(), PreferencesError> { ... }
    fn flush(&self) -> Result<(), PreferencesError> { ... }
}

Durable key/value storage owned by the application.

Implementations are Send + Sync: preferences are written from wherever the decision is made, including a worker thread.

Required Methods

fn get(&self, key: &str) -> Option<String>

Reads key, or None when it has never been written.

fn set(&self, key: &str, value: &str) -> Result<(), PreferencesError>

Writes key.

fn remove(&self, key: &str) -> Result<(), PreferencesError>

Removes key. Succeeds if it is already absent.

fn keys(&self) -> Vec<String>

Every key currently stored, in sorted order.

fn clear(&self) -> Result<(), PreferencesError>

Removes everything.

Provided Methods

fn set_many( &self, values: &BTreeMap<String, String>, ) -> Result<(), PreferencesError>

Writes a group of values. File-backed stores replace the file once. A failure may leave pending values visible; retry this batch or call flush.

fn flush(&self) -> Result<(), PreferencesError>

Retries pending writes. Success means the backend accepted all pending data.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl PreferencesStore for FilePreferences

impl PreferencesStore for MemoryPreferences