WIP: prototype for ManagedObjectProtocol

Sources/Setup/Dynamic Models/Attribute.swift

@@ -0,0 +1,166 @@
+//
+//  Attribute.swift
+//  CoreStore
+//
+//  Copyright © 2017 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: Operators
+
+infix operator .= : AssignmentPrecedence
+postfix operator *
+
+
+// MARK: - AttributeContainer
+
+public enum AttributeContainer<O: ManagedObjectProtocol> {
+    
+    // MARK: - Required
+    
+    public final class Required<V: ImportableAttributeType>: AttributeProtocol {
+        
+        public static func .= (_ attribute: AttributeContainer<O>.Required<V>, _ value: V) {
+            
+            attribute.value = value
+        }
+        
+        public static postfix func * (_ attribute: AttributeContainer<O>.Required<V>) -> V {
+            
+            return attribute.value
+        }
+        
+        public let keyPath: String
+        
+        public init(_ keyPath: String, `default`: V = V.cs_emptyValue()) {
+            
+            self.keyPath = keyPath
+            self.defaultValue = `default`.cs_toImportableNativeType()
+        }
+        
+        public var value: V {
+            
+            get {
+                
+                let object = self.accessRawObject()
+                let key = self.keyPath
+                let value = object.value(forKey: key)! as! V.ImportableNativeType
+                return V.cs_fromImportableNativeType(value)!
+            }
+            set {
+                
+                let object = self.accessRawObject()
+                let key = self.keyPath
+                object.setValue(newValue.cs_toImportableNativeType(), forKey: key)
+            }
+        }
+        
+        // MARK: Internal
+        
+        internal static var attributeType: NSAttributeType {
+            
+            return V.cs_rawAttributeType
+        }
+        
+        internal let defaultValue: Any?
+        internal let isOptional = false
+        
+        internal var accessRawObject: () -> NSManagedObject = {
+            
+            fatalError("\(O.self) property values should not be accessed")
+        }
+    }
+    
+    
+    // MARK: - Optional
+    
+    public final class Optional<V: ImportableAttributeType>: AttributeProtocol {
+        
+        public static func .= (_ attribute: AttributeContainer<O>.Optional<V>, _ value: V?) {
+            
+            attribute.value = value
+        }
+        
+        public static postfix func * (_ attribute: AttributeContainer<O>.Optional<V>) -> V? {
+            
+            return attribute.value
+        }
+        
+        public let keyPath: String
+        
+        public init(_ keyPath: String, `default`: V? = nil) {
+            
+            self.keyPath = keyPath
+            self.defaultValue = `default`?.cs_toImportableNativeType()
+        }
+        
+        public var value: V? {
+            
+            get {
+                
+                let object = self.accessRawObject()
+                let key = self.keyPath
+                guard let value = object.value(forKey: key) as! V.ImportableNativeType? else {
+                    
+                    return nil
+                }
+                return V.cs_fromImportableNativeType(value)
+            }
+            set {
+                
+                let object = self.accessRawObject()
+                let key = self.keyPath
+                object.setValue(newValue?.cs_toImportableNativeType(), forKey: key)
+            }
+        }
+        
+        
+        // MARK: Internal
+        
+        internal static var attributeType: NSAttributeType {
+            
+            return V.cs_rawAttributeType
+        }
+        
+        internal let defaultValue: Any?
+        internal let isOptional = true
+        internal var accessRawObject: () -> NSManagedObject = {
+            
+            fatalError("\(O.self) property values should not be accessed")
+        }
+    }
+}
+
+
+// MARK: - AttributeProtocol
+
+internal protocol AttributeProtocol: class {
+    
+    static var attributeType: NSAttributeType { get }
+    
+    var keyPath: String { get }
+    var isOptional: Bool { get }
+    var defaultValue: Any? { get }
+    var accessRawObject: () -> NSManagedObject { get set }
+}