feat: admit numbered iPhone companion

product-source/hololake-native-desktop/mobile/ios/Sources/HoloLakeKeychain.swift

@@ -0,0 +1,59 @@
+import Foundation
+import Security
+
+enum HoloLakeKeychain {
+    private static let service = "com.guanghulab.hololake.mobile-sync"
+    private static let account = "HLP-IOS-CLIENT-001"
+
+    static func load() throws -> StoredSession? {
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: account,
+            kSecReturnData as String: true,
+            kSecMatchLimit as String: kSecMatchLimitOne
+        ]
+        var result: CFTypeRef?
+        let status = SecItemCopyMatching(query as CFDictionary, &result)
+        if status == errSecItemNotFound { return nil }
+        guard status == errSecSuccess, let data = result as? Data else {
+            throw HoloLakeMobileError.keychain(status)
+        }
+        return try JSONDecoder().decode(StoredSession.self, from: data)
+    }
+
+    static func save(_ session: StoredSession) throws {
+        let data = try JSONEncoder().encode(session)
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: account
+        ]
+        let attributes: [String: Any] = [
+            kSecValueData as String: data,
+            kSecAttrAccessible as String: kSecAttrAccessibleWhenUnlockedThisDeviceOnly
+        ]
+        let update = SecItemUpdate(query as CFDictionary, attributes as CFDictionary)
+        if update == errSecItemNotFound {
+            var insertion = query
+            insertion.merge(attributes) { _, new in new }
+            let status = SecItemAdd(insertion as CFDictionary, nil)
+            guard status == errSecSuccess else { throw HoloLakeMobileError.keychain(status) }
+        } else if update != errSecSuccess {
+            throw HoloLakeMobileError.keychain(update)
+        }
+    }
+
+    static func remove() throws {
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: account
+        ]
+        let status = SecItemDelete(query as CFDictionary)
+        guard status == errSecSuccess || status == errSecItemNotFound else {
+            throw HoloLakeMobileError.keychain(status)
+        }
+    }
+}
+