Dactyloidae iOS initial commit

mobile/ios/Storage/SQL/Schema.swift

@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import Foundation
+
+/**
+ * Something that knows how to construct a database.
+ */
+public protocol Schema {
+    var name: String { get }
+    var version: Int { get }
+    
+    func create(_ db: SQLiteDBConnection) -> Bool
+    func update(_ db: SQLiteDBConnection, from: Int) -> Bool
+    func drop(_ db: SQLiteDBConnection) -> Bool
+}
+
+enum SchemaUpgradeResult {
+    case success
+    case failure
+    case skipped
+}