swiftUI support done for now

Sources/ListSnapshot.swift

@@ -0,0 +1,131 @@
+//
+//  ListSnapshot.swift
+//  CoreStore
+//
+//  Copyright © 2018 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.
+//
+
+#if canImport(UIKit) || canImport(AppKit)
+
+import CoreData
+
+#if canImport(UIKit)
+import UIKit
+
+#elseif canImport(AppKit)
+import AppKit
+
+#endif
+
+
+// MARK: - LiveList
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 15.0, *)
+public struct ListSnapshot<D: DynamicObject>: SnapshotResult, RandomAccessCollection, Hashable {
+
+    // MARK: Public
+    
+    public subscript<S: Sequence>(indices: S) -> [ObjectType] where S.Element == Index {
+        
+        let context = self.context!
+        let objectIDs = self.snapshotStruct.itemIdentifiers
+        return indices.map { position in
+            
+            let objectID = objectIDs[position]
+            return context.fetchExisting(objectID)!
+        }
+    }
+    
+    
+    // MARK: SnapshotResult
+    
+    public typealias ObjectType = D
+    
+    
+    // MARK: RandomAccessCollection
+    
+    public var startIndex: Index {
+        
+        return 0
+    }
+    
+    public var endIndex: Index {
+        
+        return self.snapshotStruct.numberOfItems
+    }
+    
+    public subscript(position: Index) -> ObjectType {
+        
+        let context = self.context!
+        let objectID = self.snapshotStruct.itemIdentifiers[position]
+        return context.fetchExisting(objectID)!
+    }
+    
+    
+    // MARK: Sequence
+    
+    public typealias Element = ObjectType
+    
+    public typealias Index = Int
+    
+    
+    // MARK: Equatable
+    
+    public static func == (_ lhs: Self, _ rhs: Self) -> Bool {
+        
+        return lhs.id == rhs.id
+    }
+    
+    
+    // MARK: Hashable
+    
+    public func hash(into hasher: inout Hasher) {
+        
+        hasher.combine(self.id)
+    }
+    
+    
+    // MARK: Internal
+    
+    internal init() {
+        
+        self.snapshotReference = .init()
+        self.snapshotStruct = self.snapshotReference as NSDiffableDataSourceSnapshot<NSString, NSManagedObjectID>
+        self.context = nil
+    }
+    
+    internal init(snapshotReference: NSDiffableDataSourceSnapshotReference, context: NSManagedObjectContext) {
+        
+        self.snapshotReference = snapshotReference
+        self.snapshotStruct = snapshotReference as NSDiffableDataSourceSnapshot<NSString, NSManagedObjectID>
+        self.context = context
+    }
+    
+    
+    // MARK: Private
+    
+    private let id: UUID = .init()
+    private let snapshotReference: NSDiffableDataSourceSnapshotReference
+    private let snapshotStruct: NSDiffableDataSourceSnapshot<NSString, NSManagedObjectID>
+    private let context: NSManagedObjectContext?
+}
+
+#endif