Struct DirStorage 

pub struct DirStorage { /* private fields */ }

Directory-based entity storage with ACID guarantees and automatic migrations.

Manages one file per entity. Raw IO (atomic rename, fsync, temp-file cleanup, ID encoding/decoding, directory listing) is fully delegated to local_store::DirStorage.

Responsibilities

• Serialising/deserialising entities to/from the configured format.
• Delegating all ACID / atomic-rename / lock operations to inner.
• Applying Migrator-based schema evolution on load.

Implementations

impl DirStorage

pub fn new( paths: AppPaths, domain_name: &str, migrator: Migrator, strategy: DirStorageStrategy, ) -> Result<Self, MigrationError>

Create a new DirStorage instance.

Arguments

• paths - Application paths manager.
• domain_name - Domain-specific subdirectory name (e.g., "sessions").
• migrator - Migrator instance with registered migration paths.
• strategy - Storage strategy (format, encoding, atomic-write config).

Behavior

Delegates directory creation to local_store::DirStorage::new. The base path is resolved as data_dir/domain_name and created if absent.

Errors

Returns MigrationError::Store wrapping a StoreError::IoError if directory creation fails.

pub fn save<T>( &self, entity_name: &str, id: &str, entity: T, ) -> Result<(), MigrationError>

where T: Serialize,

Save an entity to its file atomically.

Arguments

• entity_name - Entity name registered in the migrator.
• id - Unique identifier for this entity (used as the filename stem).
• entity - Value to persist; must implement serde::Serialize.

Process

1. Converts entity to its latest versioned DTO via migrator.save_domain_flat.
2. Serialises to the configured format (JSON or TOML).
3. Delegates atomic write (tmp file + fsync + rename) to inner.save_raw_string.

Errors

Returns MigrationError if:

• entity_name is not registered in the migrator.
• id contains invalid characters for the configured encoding.
• Serialisation or format conversion fails.
• The underlying file write fails.

pub fn load<D>(&self, entity_name: &str, id: &str) -> Result<D, MigrationError>

where D: DeserializeOwned,

Load an entity from its file, applying schema migrations if needed.

Arguments

• entity_name - Entity name registered in the migrator.
• id - Unique identifier for the entity.

Process

1. Reads raw string content via inner.load_raw_string.
2. Deserialises to serde_json::Value (converting from TOML if needed).
3. Applies schema migration via migrator.load_flat_from.

Errors

Returns MigrationError if the file is missing, parsing fails, or migration fails.

pub fn list_ids(&self) -> Result<Vec<String>, MigrationError>

List all entity IDs in the storage directory in lexicographic ascending order.

Returns

A Vec<String> of decoded entity IDs, sorted lexicographically.

Errors

Returns MigrationError if the directory cannot be read or a filename cannot be decoded.

pub fn load_all<D>( &self, entity_name: &str, ) -> Result<Vec<(String, D)>, MigrationError>

where D: DeserializeOwned,

Load all entities from the storage directory.

Arguments

• entity_name - Entity name registered in the migrator.

Returns

A Vec<(id, entity)> of all stored entities, ordered by ID.

Errors

Returns MigrationError if any entity fails to load. The whole operation fails atomically.

pub fn exists(&self, id: &str) -> Result<bool, MigrationError>

Check whether an entity file exists.

Arguments

• id - Entity identifier.

Returns

true if the file exists; false otherwise.

Errors

Returns MigrationError if id cannot be encoded.

pub fn delete(&self, id: &str) -> Result<(), MigrationError>

Delete an entity file (idempotent).

Arguments

• id - Entity identifier.

Behavior

Deleting a non-existent entity is not an error (local_store::DirStorage guarantees idempotency).

Errors

Returns MigrationError if the underlying file deletion fails.

pub fn base_path(&self) -> &Path

Returns a reference to the base directory path.

Returns

A reference to the resolved base directory path where entity files are stored.