Update Models, Services + docs

Summary:
- Sources: Models, Services
- Docs: README
- Added symbols: func write, func read, func delete, func exists, func list, func size (+2 more)

Stats:
- 6 files changed, 209 insertions(+), 1 deletion(-)

README.md

@@ -35,7 +35,7 @@ These helpers are internal implementation details used by `StorageRouter`. They
 - **SyncHelper** - Manages WatchConnectivity sync.
 
 ### Models
-- **StorageDomain** - userDefaults, keychain, fileSystem, encryptedFileSystem
+- **StorageDomain** - userDefaults, appGroupUserDefaults, keychain, fileSystem, encryptedFileSystem, appGroupFileSystem
 - **SecurityPolicy** - none, keychain, encrypted (AES-256 or ChaCha20-Poly1305)
 - **Serializer** - JSON, plist, Data, or custom
 - **KeyMaterialSource** - Identifier for external key material providers
@@ -95,9 +95,17 @@ try await StorageRouter.shared.remove(key)
 | Domain | Use Case |
 |--------|----------|
 | `userDefaults` | Preferences, small settings |
+| `appGroupUserDefaults` | Shared settings across extensions via App Groups |
 | `keychain` | Credentials, tokens, sensitive data |
 | `fileSystem` | Documents, cached data, large files |
 | `encryptedFileSystem` | Sensitive files with encryption policies |
+| `appGroupFileSystem` | Shared files across extensions via App Groups |
+
+## App Group Support
+
+App Group storage is explicit via `StorageDomain.appGroupUserDefaults` and `StorageDomain.appGroupFileSystem`. These require a valid App Group identifier and the corresponding entitlement on every target that needs access. If the identifier is invalid or missing, LocalData throws `StorageError.invalidAppGroupIdentifier`.
+
+Use standard `userDefaults` or `fileSystem` for data that should remain scoped to a single target, even when App Groups are configured.
 
 ## Security Options
 

Sources/LocalData/Models/StorageDomain.swift

@@ -2,7 +2,9 @@ import Foundation
 
 public enum StorageDomain: Sendable {
     case userDefaults(suite: String?)
+    case appGroupUserDefaults(identifier: String)
     case keychain(service: String)
     case fileSystem(directory: FileDirectory)
     case encryptedFileSystem(directory: FileDirectory)
+    case appGroupFileSystem(identifier: String, directory: FileDirectory)
 }

Sources/LocalData/Models/StorageError.swift

@@ -8,6 +8,7 @@ public enum StorageError: Error {
     case phoneOnlyKeyAccessedOnWatch(String)
     case watchOnlyKeyAccessedOnPhone(String)
     case invalidUserDefaultsSuite(String)
+    case invalidAppGroupIdentifier(String)
     case dataTooLargeForSync
     case notFound
     case unregisteredKey(String)

Sources/LocalData/Services/FileStorageHelper.swift

@@ -10,6 +10,21 @@ actor FileStorageHelper {
     
     // MARK: - Public Interface
 
+    /// Writes data to an App Group container.
+    public func write(
+        _ data: Data,
+        to directory: FileDirectory,
+        fileName: String,
+        appGroupIdentifier: String,
+        useCompleteFileProtection: Bool = false
+    ) throws {
+        let baseURL = try appGroupContainerURL(identifier: appGroupIdentifier)
+        let directoryURL = try resolveDirectoryURL(baseURL: baseURL, directory: directory)
+        let url = directoryURL.appendingPathComponent(fileName)
+        try ensureDirectoryExists(at: url.deletingLastPathComponent())
+        try write(data, to: url, useCompleteFileProtection: useCompleteFileProtection)
+    }
+    
     /// Writes data to a file.
     /// - Parameters:
     ///   - data: The data to write.
@@ -64,6 +79,18 @@ actor FileStorageHelper {
         }
     }
 
+    /// Reads data from an App Group container.
+    public func read(
+        from directory: FileDirectory,
+        fileName: String,
+        appGroupIdentifier: String
+    ) throws -> Data? {
+        let baseURL = try appGroupContainerURL(identifier: appGroupIdentifier)
+        let directoryURL = try resolveDirectoryURL(baseURL: baseURL, directory: directory)
+        let url = directoryURL.appendingPathComponent(fileName)
+        return try read(from: url)
+    }
+    
     /// Deletes a file.
     /// - Parameters:
     ///   - directory: The base directory.
@@ -86,6 +113,18 @@ actor FileStorageHelper {
         }
     }
 
+    /// Deletes a file from an App Group container.
+    public func delete(
+        from directory: FileDirectory,
+        fileName: String,
+        appGroupIdentifier: String
+    ) throws {
+        let baseURL = try appGroupContainerURL(identifier: appGroupIdentifier)
+        let directoryURL = try resolveDirectoryURL(baseURL: baseURL, directory: directory)
+        let url = directoryURL.appendingPathComponent(fileName)
+        try delete(file: url)
+    }
+    
     /// Checks if a file exists.
     /// - Parameters:
     ///   - directory: The base directory.
@@ -99,6 +138,22 @@ actor FileStorageHelper {
         return FileManager.default.fileExists(atPath: url.path)
     }
 
+    /// Checks if a file exists in an App Group container.
+    public func exists(
+        in directory: FileDirectory,
+        fileName: String,
+        appGroupIdentifier: String
+    ) -> Bool {
+        do {
+            let baseURL = try appGroupContainerURL(identifier: appGroupIdentifier)
+            let directoryURL = try resolveDirectoryURL(baseURL: baseURL, directory: directory)
+            let url = directoryURL.appendingPathComponent(fileName)
+            return FileManager.default.fileExists(atPath: url.path)
+        } catch {
+            return false
+        }
+    }
+    
     /// Lists all files in a directory.
     /// - Parameter directory: The directory to list.
     /// - Returns: An array of file names.
@@ -117,6 +172,13 @@ actor FileStorageHelper {
         }
     }
 
+    /// Lists all files in an App Group container directory.
+    public func list(in directory: FileDirectory, appGroupIdentifier: String) throws -> [String] {
+        let baseURL = try appGroupContainerURL(identifier: appGroupIdentifier)
+        let directoryURL = try resolveDirectoryURL(baseURL: baseURL, directory: directory)
+        return try list(in: directoryURL)
+    }
+    
     /// Gets the size of a file in bytes.
     /// - Parameters:
     ///   - directory: The base directory.
@@ -141,6 +203,18 @@ actor FileStorageHelper {
         }
     }
 
+    /// Gets the size of a file in an App Group container.
+    public func size(
+        of directory: FileDirectory,
+        fileName: String,
+        appGroupIdentifier: String
+    ) throws -> Int64? {
+        let baseURL = try appGroupContainerURL(identifier: appGroupIdentifier)
+        let directoryURL = try resolveDirectoryURL(baseURL: baseURL, directory: directory)
+        let url = directoryURL.appendingPathComponent(fileName)
+        return try size(of: url)
+    }
+    
     // MARK: - Private Helpers
     
     private func ensureDirectoryExists(at url: URL) throws {
@@ -158,4 +232,87 @@ actor FileStorageHelper {
             throw StorageError.fileError(error)
         }
     }
+
+    private func write(_ data: Data, to url: URL, useCompleteFileProtection: Bool) throws {
+        var options: Data.WritingOptions = [.atomic]
+        if useCompleteFileProtection {
+            options.insert(.completeFileProtection)
+        }
+
+        do {
+            try data.write(to: url, options: options)
+        } catch {
+            throw StorageError.fileError(error)
+        }
+    }
+
+    private func read(from url: URL) throws -> Data? {
+        guard FileManager.default.fileExists(atPath: url.path) else {
+            return nil
+        }
+
+        do {
+            return try Data(contentsOf: url)
+        } catch {
+            throw StorageError.fileError(error)
+        }
+    }
+
+    private func delete(file url: URL) throws {
+        guard FileManager.default.fileExists(atPath: url.path) else {
+            return
+        }
+
+        do {
+            try FileManager.default.removeItem(at: url)
+        } catch {
+            throw StorageError.fileError(error)
+        }
+    }
+
+    private func list(in url: URL) throws -> [String] {
+        guard FileManager.default.fileExists(atPath: url.path) else {
+            return []
+        }
+
+        do {
+            return try FileManager.default.contentsOfDirectory(atPath: url.path)
+        } catch {
+            throw StorageError.fileError(error)
+        }
+    }
+
+    private func size(of url: URL) throws -> Int64? {
+        guard FileManager.default.fileExists(atPath: url.path) else {
+            return nil
+        }
+
+        do {
+            let attributes = try FileManager.default.attributesOfItem(atPath: url.path)
+            return attributes[.size] as? Int64
+        } catch {
+            throw StorageError.fileError(error)
+        }
+    }
+
+    private func appGroupContainerURL(identifier: String) throws -> URL {
+        guard let url = FileManager.default.containerURL(
+            forSecurityApplicationGroupIdentifier: identifier
+        ) else {
+            throw StorageError.invalidAppGroupIdentifier(identifier)
+        }
+        return url
+    }
+
+    private func resolveDirectoryURL(baseURL: URL, directory: FileDirectory) throws -> URL {
+        switch directory {
+        case .documents:
+            return baseURL.appending(path: "Documents")
+        case .caches:
+            return baseURL.appending(path: "Library/Caches")
+        case .custom(let url):
+            let relativePath = url.path.trimmingCharacters(in: CharacterSet(charactersIn: "/"))
+            return baseURL.appending(path: relativePath)
+        }
+    }
 }

Sources/LocalData/Services/StorageAuditReport.swift

@@ -30,12 +30,16 @@ public struct StorageAuditReport: Sendable {
         switch domain {
         case .userDefaults(let suite):
             return "userDefaults(\(suite ?? "standard"))"
+        case .appGroupUserDefaults(let identifier):
+            return "appGroupUserDefaults(\(identifier))"
         case .keychain(let service):
             return "keychain(\(service))"
         case .fileSystem(let directory):
             return "fileSystem(\(string(for: directory)))"
         case .encryptedFileSystem(let directory):
             return "encryptedFileSystem(\(string(for: directory)))"
+        case .appGroupFileSystem(let identifier, let directory):
+            return "appGroupFileSystem(\(identifier), \(string(for: directory)))"
         }
     }
 

Sources/LocalData/Services/StorageRouter.swift

@@ -85,10 +85,18 @@ public actor StorageRouter: StorageProviding {
         switch key.domain {
         case .userDefaults(let suite):
             return try await UserDefaultsHelper.shared.exists(forKey: key.name, suite: suite)
+        case .appGroupUserDefaults(let identifier):
+            return try await UserDefaultsHelper.shared.exists(forKey: key.name, suite: identifier)
         case .keychain(let service):
             return try await KeychainHelper.shared.exists(service: service, key: key.name)
         case .fileSystem(let directory), .encryptedFileSystem(let directory):
             return await FileStorageHelper.shared.exists(in: directory, fileName: key.name)
+        case .appGroupFileSystem(let identifier, let directory):
+            return await FileStorageHelper.shared.exists(
+                in: directory,
+                fileName: key.name,
+                appGroupIdentifier: identifier
+            )
         }
     }
     
@@ -207,6 +215,9 @@ public actor StorageRouter: StorageProviding {
         case .userDefaults(let suite):
             try await UserDefaultsHelper.shared.set(data, forKey: key.name, suite: suite)
             
+        case .appGroupUserDefaults(let identifier):
+            try await UserDefaultsHelper.shared.set(data, forKey: key.name, suite: identifier)
+            
         case .keychain(let service):
             guard case let .keychain(accessibility, accessControl) = key.security else {
                 throw StorageError.securityApplicationFailed
@@ -234,6 +245,15 @@ public actor StorageRouter: StorageProviding {
                 fileName: key.name,
                 useCompleteFileProtection: true
             )
+            
+        case .appGroupFileSystem(let identifier, let directory):
+            try await FileStorageHelper.shared.write(
+                data,
+                to: directory,
+                fileName: key.name,
+                appGroupIdentifier: identifier,
+                useCompleteFileProtection: false
+            )
         }
     }
     
@@ -241,12 +261,20 @@ public actor StorageRouter: StorageProviding {
         switch key.domain {
         case .userDefaults(let suite):
             return try await UserDefaultsHelper.shared.get(forKey: key.name, suite: suite)
+        case .appGroupUserDefaults(let identifier):
+            return try await UserDefaultsHelper.shared.get(forKey: key.name, suite: identifier)
             
         case .keychain(let service):
             return try await KeychainHelper.shared.get(service: service, key: key.name)
             
         case .fileSystem(let directory), .encryptedFileSystem(let directory):
             return try await FileStorageHelper.shared.read(from: directory, fileName: key.name)
+        case .appGroupFileSystem(let identifier, let directory):
+            return try await FileStorageHelper.shared.read(
+                from: directory,
+                fileName: key.name,
+                appGroupIdentifier: identifier
+            )
         }
     }
     
@@ -254,12 +282,20 @@ public actor StorageRouter: StorageProviding {
         switch key.domain {
         case .userDefaults(let suite):
             try await UserDefaultsHelper.shared.remove(forKey: key.name, suite: suite)
+        case .appGroupUserDefaults(let identifier):
+            try await UserDefaultsHelper.shared.remove(forKey: key.name, suite: identifier)
             
         case .keychain(let service):
             try await KeychainHelper.shared.delete(service: service, key: key.name)
             
         case .fileSystem(let directory), .encryptedFileSystem(let directory):
             try await FileStorageHelper.shared.delete(from: directory, fileName: key.name)
+        case .appGroupFileSystem(let identifier, let directory):
+            try await FileStorageHelper.shared.delete(
+                from: directory,
+                fileName: key.name,
+                appGroupIdentifier: identifier
+            )
         }
     }