Struct FileStorage 

pub struct FileStorage { /* private fields */ }

File storage with ACID guarantees and automatic migrations.

Provides:

• Atomicity: Updates are all-or-nothing via tmp file + atomic rename
• Consistency: Format validation on load/save
• Isolation: File locking prevents concurrent modifications
• Durability: Explicit fsync before rename

Implementations

impl FileStorage

pub fn new( path: PathBuf, migrator: Migrator, strategy: FileStorageStrategy, ) -> Result<Self, MigrationError>

Create a new FileStorage instance and load data from file.

This combines initialization and loading into a single operation.

Arguments

• path - Path to the storage file
• migrator - Migrator instance with registered migration paths
• strategy - Storage strategy configuration

Behavior

Depends on strategy.load_behavior:

• CreateIfMissing: Creates empty config if file doesn’t exist
• ErrorIfMissing: Returns error if file doesn’t exist

Example

let strategy = FileStorageStrategy::default();
let migrator = Migrator::new();
let storage = FileStorage::new(
    PathBuf::from("config.toml"),
    migrator,
    strategy
)?;

pub fn save(&self) -> Result<(), MigrationError>

Save current state to file atomically.

Uses a temporary file + atomic rename to ensure durability. Retries according to strategy.atomic_write.retry_count.

pub fn config(&self) -> &ConfigMigrator

Get immutable reference to the ConfigMigrator.

pub fn config_mut(&mut self) -> &mut ConfigMigrator

Get mutable reference to the ConfigMigrator.

pub fn query<T>(&self, key: &str) -> Result<Vec<T>, MigrationError>

where T: Queryable + for<'de> Deserialize<'de>,

Query entities from storage.

Delegates to ConfigMigrator::query().

pub fn update<T>( &mut self, key: &str, value: Vec<T>, ) -> Result<(), MigrationError>

where T: Queryable + Serialize,

Update entities in memory (does not save to file).

Delegates to ConfigMigrator::update().

pub fn update_and_save<T>( &mut self, key: &str, value: Vec<T>, ) -> Result<(), MigrationError>

where T: Queryable + Serialize,

Update entities and immediately save to file atomically.

pub fn path(&self) -> &Path

Returns a reference to the storage file path.

Returns

A reference to the file path where the configuration is stored.