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Overview

PrismStorage provides a single protocol for all persistence needs. Every engine conforms to the same interface, making stores interchangeable and composable. 
import Prism

// Sync stores
let defaults = PrismDefaultsStore()
let keychain = PrismKeychainStore(service: "MyApp")

// Async (actor-based) stores
let disk = PrismDiskStore(directory: .caches)
let memory = PrismMemoryStore(maxEntries: 500)

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Unified Protocol

public protocol PrismStorageProtocol: Sendable {
    func save<T: Codable & Sendable>(_ value: T, forKey key: String) throws
    func load<T: Codable & Sendable>(_ type: T.Type, forKey key: String) throws -> T?
    func delete(forKey key: String) throws
    func exists(forKey key: String) throws -> Bool
    func clear() throws
    func keys() throws -> [String]
}
Actor-based stores conform to PrismAsyncStorageProtocol — same methods with async throws.

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Architecture

LayerComponents
EnginesDefaultsStore, DiskStore, MemoryStore, KeychainStore, ModelStore
WrappersEncryptedStore, CompressedStore, CompositeStore, StorageObserver
UtilitiesBatchWriter, StorageMigrator, LiveQuery, Query Builder

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Quick Start

// Save and load any Codable
let store = PrismDefaultsStore()
try store.save(user, forKey: "currentUser")
let user = try store.load(User.self, forKey: "currentUser")

// Encrypted storage
let encrypted = PrismEncryptedStore(wrapping: store, key: symmetricKey)
try encrypted.save(secret, forKey: "token") // AES-GCM transparent

// Multi-tier cache (memory → disk)
let composite = PrismCompositeStore(stores: [memory, disk])
let value = try composite.load(Config.self, forKey: "settings")
// Cache miss on memory? Falls through to disk, populates memory

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Concurrency

All stores are Sendable. Actor-based stores (PrismDiskStore, PrismMemoryStore, PrismModelStore) provide safe concurrent access. Sync stores use NSLock internally.

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Next Steps

Defaults & Disk

UserDefaults and file-based persistence.

SwiftData

Type-safe persistence with @Model and PrismModelStore.

Encryption & Compression

AES-GCM encryption and LZFSE/LZMA compression wrappers.

Advanced

Composite stores, batch operations, migrations, observation.
Need to store secrets securely? See Encryption & Keychain in PrismSecurity for keychain-backed secret storage with biometric protection.