Struct OrInMemory 

pub struct OrInMemory<B = StoreBuilder>(/* private fields */);

A StoreBuilder that opens a store in memory where the file will not open, and says which it did.

For an application that would rather run without its settings than not run: a file another process holds, a directory it cannot write, a file that will not read, a file a newer release wrote that this one’s steps turn down. The store in memory starts empty, so every declared struct seeds its defaults, and it writes nothing: the file stays for whoever can read it.

The refusal comes back whole in Persistence::InMemory, so the application can tell the user, or try again later on its own terms.

let (store, persistence) = StoreBuilder::new(&*path).or_in_memory().build();

if let Persistence::InMemory { because } = &persistence {
    eprintln!("settings will not be saved this run: {because}");
}

Implementations

impl OrInMemory<WithSteps>

pub fn migrate_global( self, ) -> Result<(GlobalStoreGuard, MigrationReport, Persistence), InitGlobal>

OrInMemory::migrate, put in place.

impl OrInMemory

pub fn build_global(self) -> Result<(GlobalStoreGuard, Persistence), InitGlobal>

OrInMemory::build, put in place. The one refusal left is a store already there.

pub fn migrate_global( self, ) -> Result<(GlobalStoreGuard, MigrationReport, Persistence), InitGlobal>

OrInMemory::migrate, put in place.

impl OrInMemory

pub fn build(self) -> (Store, Persistence)

StoreBuilder::build, or a store in memory.

pub fn migrate(self) -> (Store, MigrationReport, Persistence)

StoreBuilder::migrate, or a store in memory.

The report is the store’s that came back: on a fall back, that is the store in memory, which had nothing to migrate. What the file’s open said is in the refusal.

impl OrInMemory<WithSteps>

pub fn migrate(self) -> (Store, MigrationReport, Persistence)

WithSteps::migrate, or a store in memory.