async API prototypes

Sources/MigrationProgress.swift

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+//
+//  MigrationProgress.swift
+//  CoreStore
+//
+//  Copyright © 2021 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+import CoreData
+import Foundation
+
+
+// MARK: - MigrationProgress
+
+/**
+ A `MigrationProgress` contains info on a `LocalStorage`'s setup progress.
+
+ - SeeAlso: DataStack.reactive.addStorage(_:)
+ - SeeAlso: DataStack.async.addStorage(_:)
+ */
+public enum MigrationProgress<T: LocalStorage> {
+
+    /**
+     The `LocalStorage` is currently being migrated
+     */
+    case migrating(storage: T, progressObject: Progress)
+
+    /**
+     The `LocalStorage` has been added to the `DataStack` and is ready for reading and writing
+     */
+    case finished(storage: T, migrationRequired: Bool)
+
+    /**
+     The fraction of the overall work completed by the migration. Returns a value between 0.0 and 1.0, inclusive.
+     */
+    public var fractionCompleted: Double {
+
+        switch self {
+
+        case .migrating(_, let progressObject):
+            return progressObject.fractionCompleted
+
+        case .finished:
+            return 1
+        }
+    }
+
+    /**
+     Returns `true` if the storage was successfully added to the stack, `false` otherwise.
+     */
+    public var isCompleted: Bool {
+
+        switch self {
+
+        case .migrating:
+            return false
+
+        case .finished:
+            return true
+        }
+    }
+}