Merge branch 'prototype/Swift_3_2' into prototype/Swift_4_0

Sources/AsynchronousDataTransaction.swift

@@ -210,6 +210,7 @@ public final class AsynchronousDataTransaction: BaseDataTransaction {
             group.leave()
         }
         group.wait()
+        self.context.reset()
     }
     
     

Sources/CoreStoreObject.swift

@@ -135,3 +135,23 @@ open /*abstract*/ class CoreStoreObject: DynamicObject, Hashable {
         }
     }
 }
+
+
+// MARK: - DynamicObject where Self: CoreStoreObject
+
+public extension DynamicObject where Self: CoreStoreObject {
+    
+    public func partialObject() -> PartialObject<Self> {
+        
+        CoreStore.assert(
+            !self.isMeta,
+            "Attempted to create a \(cs_typeName(PartialObject<Self>.self)) from a meta object. Meta objects are only used for querying keyPaths and infering types."
+        )
+        return PartialObject<Self>(self.rawObject!)
+    }
+    
+    internal static var meta: Self {
+        
+        return self.init(asMeta: ())
+    }
+}

Sources/DynamicObject.swift

@@ -155,14 +155,3 @@ extension CoreStoreObject {
         return self.rawObject!
     }
 }
-
-
-// MARK: - Internal
-
-internal extension DynamicObject where Self: CoreStoreObject {
-    
-    internal static var meta: Self {
-        
-        return self.init(asMeta: ())
-    }
-}

Sources/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>4.0.4</string>
+	<string>4.0.5</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>

Sources/ListMonitor.swift

@@ -704,13 +704,13 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
                     
                     guard let `self` = self,
                         let userInfo = note.userInfo,
-                        let object = userInfo[String(describing: NSManagedObject.self)] as? ObjectType else {
+                        let rawObject = userInfo[String(describing: NSManagedObject.self)] as? NSManagedObject else {
                             
                             return
                     }
                     callback(
                         self,
-                        object,
+                        ObjectType.cs_fromRaw(object: rawObject),
                         userInfo[String(describing: IndexPath.self)] as? IndexPath,
                         userInfo["\(String(describing: IndexPath.self)).New"] as? IndexPath
                     )

Sources/PartialObject.swift

@@ -0,0 +1,173 @@
+//
+//  PartialObject.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: - PartialObject
+
+/**
+ A `PartialObject` is only used when overriding getters and setters for `CoreStoreObject` properties. Custom getters and setters are implemented as a closure that "overrides" the default property getter/setter. The closure receives a `PartialObject<O>`, which acts as a fast, type-safe KVC interface for `CoreStoreObject`. The reason a `CoreStoreObject` instance is not passed directly is because the Core Data runtime is not aware of `CoreStoreObject` properties' static typing, and so loading those info everytime KVO invokes this accessor method incurs a heavy performance hit (especially in KVO-heavy operations such as `ListMonitor` observing.) When accessing the property value from `PartialObject<O>`, make sure to use `PartialObject<O>.persistentValue(for:)` instead of `PartialObject<O>.value(for:)`, which would unintentionally execute the same closure again recursively.
+ */
+public struct PartialObject<O: CoreStoreObject> {
+    
+    public func completeObject() -> O {
+        
+        return O.cs_fromRaw(object: self.rawObject)
+    }
+    
+    
+    // MARK: Value.Required accessors/mutators
+    
+    public func value<V>(for property: (O) -> ValueContainer<O>.Required<V>) -> V {
+        
+        return V.cs_fromQueryableNativeType(
+            self.rawObject.value(forKey: property(O.meta).keyPath)! as! V.QueryableNativeType
+        )!
+    }
+    
+    public func setValue<V>(_ value: V, for property: (O) -> ValueContainer<O>.Required<V>) {
+        
+        self.rawObject.setValue(
+            value.cs_toQueryableNativeType(),
+            forKey: property(O.meta).keyPath
+        )
+    }
+    
+    public func primitiveValue<V>(for property: (O) -> ValueContainer<O>.Required<V>) -> V {
+        
+        return V.cs_fromQueryableNativeType(
+            self.rawObject.primitiveValue(forKey: property(O.meta).keyPath)! as! V.QueryableNativeType
+        )!
+    }
+    
+    public func setPrimitiveValue<V>(_ value: V, for property: (O) -> ValueContainer<O>.Required<V>) {
+        
+        self.rawObject.setPrimitiveValue(
+            value.cs_toQueryableNativeType(),
+            forKey: property(O.meta).keyPath
+        )
+    }
+    
+    
+    // MARK: Value.Optional utilities
+    
+    public func value<V>(for property: (O) -> ValueContainer<O>.Optional<V>) -> V? {
+        
+        return (self.rawObject.value(forKey: property(O.meta).keyPath) as! V.QueryableNativeType?)
+            .flatMap(V.cs_fromQueryableNativeType)
+    }
+    
+    public func setValue<V>(_ value: V?, for property: (O) -> ValueContainer<O>.Optional<V>) {
+        
+        self.rawObject.setValue(
+            value?.cs_toQueryableNativeType(),
+            forKey: property(O.meta).keyPath
+        )
+    }
+    
+    public func primitiveValue<V>(for property: (O) -> ValueContainer<O>.Optional<V>) -> V? {
+        
+        return (self.rawObject.primitiveValue(forKey: property(O.meta).keyPath) as! V.QueryableNativeType?)
+            .flatMap(V.cs_fromQueryableNativeType)
+    }
+    
+    public func setPrimitiveValue<V>(_ value: V?, for property: (O) -> ValueContainer<O>.Optional<V>) {
+        
+        self.rawObject.setPrimitiveValue(
+            value?.cs_toQueryableNativeType(),
+            forKey: property(O.meta).keyPath
+        )
+    }
+    
+    
+    // MARK: Transformable.Required utilities
+    
+    public func value<V>(for property: (O) -> TransformableContainer<O>.Required<V>) -> V {
+        
+        return self.rawObject.value(forKey: property(O.meta).keyPath)! as! V
+    }
+    
+    public func setValue<V>(_ value: V, for property: (O) -> TransformableContainer<O>.Required<V>) {
+        
+        self.rawObject.setValue(
+            value,
+            forKey: property(O.meta).keyPath
+        )
+    }
+    
+    public func primitiveValue<V>(for property: (O) -> TransformableContainer<O>.Required<V>) -> V {
+        
+        return self.rawObject.primitiveValue(forKey: property(O.meta).keyPath)! as! V
+    }
+    
+    public func setPrimitiveValue<V>(_ value: V, for property: (O) -> TransformableContainer<O>.Required<V>) {
+        
+        self.rawObject.setPrimitiveValue(
+            value,
+            forKey: property(O.meta).keyPath
+        )
+    }
+    
+    
+    // MARK: Transformable.Optional utilities
+    
+    public func value<V>(for property: (O) -> TransformableContainer<O>.Optional<V>) -> V? {
+        
+        return self.rawObject.value(forKey: property(O.meta).keyPath) as! V?
+    }
+    
+    public func setValue<V>(_ value: V?, for property: (O) -> TransformableContainer<O>.Optional<V>) {
+        
+        self.rawObject.setValue(
+            value,
+            forKey: property(O.meta).keyPath
+        )
+    }
+    
+    public func primitiveValue<V>(for property: (O) -> TransformableContainer<O>.Optional<V>) -> V? {
+        
+        return self.rawObject.primitiveValue(forKey: property(O.meta).keyPath) as! V?
+    }
+    
+    public func setPrimitiveValue<V>(_ value: V?, for property: (O) -> TransformableContainer<O>.Optional<V>) {
+        
+        self.rawObject.setPrimitiveValue(
+            value,
+            forKey: property(O.meta).keyPath
+        )
+    }
+    
+    
+    // MARK: Internal
+    
+    internal let rawObject: NSManagedObject
+    
+    internal init(_ rawObject: NSManagedObject) {
+        
+        self.rawObject = rawObject
+    }
+}

Sources/SynchronousDataTransaction.swift

@@ -158,6 +158,10 @@ public final class SynchronousDataTransaction: BaseDataTransaction {
         self.isCommitted = true
         let result = self.context.saveSynchronously(waitForMerge: waitForMerge)
         self.result = result
+        defer {
+            
+            self.context.reset()
+        }
         return result
     }
     

Sources/Value.swift

@@ -93,12 +93,24 @@ public enum ValueContainer<O: CoreStoreObject> {
          ```
          class Person: CoreStoreObject {
              let title = Value.Required<String>("title", default: "Mr.")
-             let name = Value.Required<String>(
-                 "name",
-                 customGetter: { (`self`, getValue) in
-                    return "\(self.title.value) \(getValue())"
-                 }
+             let name = Value.Required<String>("name")
+             let displayName = Value.Required<String>(
+                 "displayName",
+                 isTransient: true,
+                 customGetter: Person.getName(_:)
              )
+         
+             private static func getName(_ partialObject: PartialObject<Person>) -> String {
+                 let cachedDisplayName = partialObject.primitiveValue(for: { $0.displayName })
+                 if !cachedDisplayName.isEmpty {
+                     return cachedDisplayName
+                 }
+                 let title = partialObject.value(for: { $0.title })
+                 let name = partialObject.value(for: { $0.name })
+                 let displayName = "\(title) \(name)"
+                 partialObject.setPrimitiveValue(displayName, for: { $0.displayName })
+                 return displayName
+             }
          }
          ```
          - parameter keyPath: the permanent attribute name for this property.
@@ -107,13 +119,8 @@ public enum ValueContainer<O: CoreStoreObject> {
          - parameter isTransient: `true` if the property is transient, otherwise `false`. Defaults to `false` if not specified. The transient flag specifies whether or not a property's value is ignored when an object is saved to a persistent store. Transient properties are not saved to the persistent store, but are still managed for undo, redo, validation, and so on.
          - parameter versionHashModifier: used to mark or denote a property as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
          - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
-         - parameter customGetter: use this closure to make final transformations to the property's value before returning from the getter.
-         - parameter self: the `CoreStoreObject`
-         - parameter getValue: the original getter for the property
-         - parameter customSetter: use this closure to make final transformations to the new value before assigning to the property.
-         - parameter setValue: the original setter for the property
-         - parameter finalNewValue: the transformed new value
-         - parameter originalNewValue: the original new value
+         - parameter customGetter: use this closure as an "override" for the default property getter. The closure receives a `PartialObject<O>`, which acts as a fast, type-safe KVC interface for `CoreStoreObject`. The reason a `CoreStoreObject` instance is not passed directly is because the Core Data runtime is not aware of `CoreStoreObject` properties' static typing, and so loading those info everytime KVO invokes this accessor method incurs a cumulative performance hit (especially in KVO-heavy operations such as `ListMonitor` observing.) When accessing the property value from `PartialObject<O>`, make sure to use `PartialObject<O>.primitiveValue(for:)` instead of `PartialObject<O>.value(for:)`, which would unintentionally execute the same closure again recursively.
+         - parameter customSetter: use this closure as an "override" for the default property setter. The closure receives a `PartialObject<O>`, which acts as a fast, type-safe KVC interface for `CoreStoreObject`. The reason a `CoreStoreObject` instance is not passed directly is because the Core Data runtime is not aware of `CoreStoreObject` properties' static typing, and so loading those info everytime KVO invokes this accessor method incurs a cumulative performance hit (especially in KVO-heavy operations such as `ListMonitor` observing.) When accessing the property value from `PartialObject<O>`, make sure to use `PartialObject<O>.setPrimitiveValue(_:for:)` instead of `PartialObject<O>.setValue(_:for:)`, which would unintentionally execute the same closure again recursively.
          - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
          */
         public init(
@@ -123,8 +130,8 @@ public enum ValueContainer<O: CoreStoreObject> {
             isTransient: Bool = false,
             versionHashModifier: String? = nil,
             renamingIdentifier: String? = nil,
-            customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)? = nil,
-            customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void)? = nil,
+            customGetter: ((_ partialObject: PartialObject<O>) -> V)? = nil,
+            customSetter: ((_ partialObject: PartialObject<O>, _ newValue: V) -> Void)? = nil,
             affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
             
             self.keyPath = keyPath
@@ -155,17 +162,13 @@ public enum ValueContainer<O: CoreStoreObject> {
                         object.rawObject!.isRunningInAllowedQueue() == true,
                         "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
                     )
-                    let customGetter = (self.customGetter ?? { $1() })
-                    return customGetter(
-                        object,
-                        { () -> V in
-                            
-                            return object.rawObject!.getValue(
-                                forKvcKey: self.keyPath,
-                                didGetValue: { V.cs_fromQueryableNativeType($0 as! V.QueryableNativeType)! }
-                            )
-                        }
-                    )
+                    if let customGetter = self.customGetter {
+                        
+                        return customGetter(PartialObject<O>(object.rawObject!))
+                    }
+                    return V.cs_fromQueryableNativeType(
+                        object.rawObject!.value(forKey: self.keyPath)! as! V.QueryableNativeType
+                    )!
                 }
             }
             set {
@@ -181,21 +184,16 @@ public enum ValueContainer<O: CoreStoreObject> {
                         "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
                     )
                     CoreStore.assert(
-                        self.isTransient || object.rawObject!.isEditableInContext() == true,
+                        object.rawObject!.isEditableInContext() == true,
                         "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
                     )
-                    let customSetter = (self.customSetter ?? { $1($2) })
-                    customSetter(
-                        object,
-                        { (newValue: V) -> Void in
-                            
-                            object.rawObject!.setValue(
-                                newValue,
-                                forKvcKey: self.keyPath,
-                                willSetValue: { $0.cs_toQueryableNativeType() }
-                            )
-                        },
-                        newValue
+                    if let customSetter = self.customSetter {
+                        
+                        return customSetter(PartialObject<O>(object.rawObject!), newValue)
+                    }
+                    return object.rawObject!.setValue(
+                        newValue.cs_toQueryableNativeType(),
+                        forKey: self.keyPath
                     )
                 }
             }
@@ -230,15 +228,12 @@ public enum ValueContainer<O: CoreStoreObject> {
             return { (_ id: Any) -> Any? in
                 
                 let rawObject = id as! CoreStoreManagedObject
-                let value = customGetter(
-                    O.cs_fromRaw(object: rawObject),
-                    {
-                        rawObject.getValue(
-                            forKvcKey: keyPath,
-                            didGetValue: { V.cs_fromQueryableNativeType($0 as! V.QueryableNativeType!)! }
-                        )
-                    }
-                )
+                rawObject.willAccessValue(forKey: keyPath)
+                defer {
+                    
+                    rawObject.didAccessValue(forKey: keyPath)
+                }
+                let value = customGetter(PartialObject<O>(rawObject))
                 return value.cs_toQueryableNativeType()
             }
         }
@@ -253,16 +248,13 @@ public enum ValueContainer<O: CoreStoreObject> {
             return { (_ id: Any, _ newValue: Any?) -> Void in
                 
                 let rawObject = id as! CoreStoreManagedObject
+                rawObject.willChangeValue(forKey: keyPath)
+                defer {
+                    
+                    rawObject.didChangeValue(forKey: keyPath)
+                }
                 customSetter(
-                    O.cs_fromRaw(object: rawObject),
-                    { (userValue: V) -> Void in
-                        
-                        rawObject.setValue(
-                            userValue,
-                            forKvcKey: keyPath,
-                            willSetValue: { $0.cs_toQueryableNativeType() }
-                        )
-                    },
+                    PartialObject<O>(rawObject),
                     V.cs_fromQueryableNativeType(newValue as! V.QueryableNativeType)!
                 )
             }
@@ -271,8 +263,8 @@ public enum ValueContainer<O: CoreStoreObject> {
         
         // MARK: Private
         
-        private let customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)?
-        private let customSetter: ((_ `self`: O, _ setValue: (V) -> Void, _ newValue: V) -> Void)?
+        private let customGetter: ((_ partialObject: PartialObject<O>) -> V)?
+        private let customSetter: ((_ partialObject: PartialObject<O>, _ newValue: V) -> Void)?
     }
     
     
@@ -295,13 +287,24 @@ public enum ValueContainer<O: CoreStoreObject> {
          Initializes the metadata for the property.
          ```
          class Person: CoreStoreObject {
-             let title = Value.Required<String>("title", default: "Mr.")
-             let name = Value.Required<String>(
-                 "name",
-                 customGetter: { (`self`, getValue) in
-                     return "\(self.title.value) \(getValue())"
-                 }
+             let title = Value.Optional<String>("title", default: "Mr.")
+             let name = Value.Optional<String>("name")
+             let displayName = Value.Optional<String>(
+                 "displayName",
+                 isTransient: true,
+                 customGetter: Person.getName(_:)
              )
+             
+             private static func getName(_ partialObject: PartialObject<Person>) -> String? {
+                 if let cachedDisplayName = partialObject.primitiveValue(for: { $0.displayName }) {
+                    return cachedDisplayName
+                 }
+                 let title = partialObject.value(for: { $0.title })
+                 let name = partialObject.value(for: { $0.name })
+                 let displayName = "\(title) \(name)"
+                 partialObject.setPrimitiveValue(displayName, for: { $0.displayName })
+                 return displayName
+             }
          }
          ```
          - parameter keyPath: the permanent attribute name for this property.
@@ -326,8 +329,8 @@ public enum ValueContainer<O: CoreStoreObject> {
             isTransient: Bool = false,
             versionHashModifier: String? = nil,
             renamingIdentifier: String? = nil,
-            customGetter: ((_ `self`: O, _ getValue: () -> V?) -> V?)? = nil,
-            customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V?) -> Void, _ originalNewValue: V?) -> Void)? = nil,
+            customGetter: ((_ partialObject: PartialObject<O>) -> V?)? = nil,
+            customSetter: ((_ partialObject: PartialObject<O>, _ newValue: V?) -> Void)? = nil,
             affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
             
             self.keyPath = keyPath
@@ -358,17 +361,12 @@ public enum ValueContainer<O: CoreStoreObject> {
                         object.rawObject!.isRunningInAllowedQueue() == true,
                         "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
                     )
-                    let customGetter = (self.customGetter ?? { $1() })
-                    return customGetter(
-                        object,
-                        { () -> V? in
-                            
-                            return object.rawObject!.getValue(
-                                forKvcKey: self.keyPath,
-                                didGetValue: { ($0 as! V.QueryableNativeType?).flatMap(V.cs_fromQueryableNativeType) }
-                            )
-                        }
-                    )
+                    if let customGetter = self.customGetter {
+                        
+                        return customGetter(PartialObject<O>(object.rawObject!))
+                    }
+                    return (object.rawObject!.value(forKey: self.keyPath) as! V.QueryableNativeType?)
+                        .flatMap(V.cs_fromQueryableNativeType)
                 }
             }
             set {
@@ -384,21 +382,16 @@ public enum ValueContainer<O: CoreStoreObject> {
                         "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
                     )
                     CoreStore.assert(
-                        self.isTransient || object.rawObject!.isEditableInContext() == true,
+                        object.rawObject!.isEditableInContext() == true,
                         "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
                     )
-                    let customSetter = (self.customSetter ?? { $1($2) })
-                    customSetter(
-                        object,
-                        { (newValue: V?) -> Void in
-                            
-                            object.rawObject!.setValue(
-                                newValue,
-                                forKvcKey: self.keyPath,
-                                willSetValue: { $0?.cs_toQueryableNativeType() }
-                            )
-                        },
-                        newValue
+                    if let customSetter = self.customSetter {
+                        
+                        return customSetter(PartialObject<O>(object.rawObject!), newValue)
+                    }
+                    object.rawObject!.setValue(
+                        newValue?.cs_toQueryableNativeType(),
+                        forKey: self.keyPath
                     )
                 }
             }
@@ -432,15 +425,12 @@ public enum ValueContainer<O: CoreStoreObject> {
             return { (_ id: Any) -> Any? in
                 
                 let rawObject = id as! CoreStoreManagedObject
-                let value = customGetter(
-                    O.cs_fromRaw(object: rawObject),
-                    {
-                        rawObject.getValue(
-                            forKvcKey: keyPath,
-                            didGetValue: { ($0 as! V.QueryableNativeType?).flatMap(V.cs_fromQueryableNativeType) }
-                        )
-                    }
-                )
+                rawObject.willAccessValue(forKey: keyPath)
+                defer {
+                    
+                    rawObject.didAccessValue(forKey: keyPath)
+                }
+                let value = customGetter(PartialObject<O>(rawObject))
                 return value?.cs_toQueryableNativeType()
             }
         }
@@ -455,16 +445,13 @@ public enum ValueContainer<O: CoreStoreObject> {
             return { (_ id: Any, _ newValue: Any?) -> Void in
                 
                 let rawObject = id as! CoreStoreManagedObject
+                rawObject.willChangeValue(forKey: keyPath)
+                defer {
+                    
+                    rawObject.didChangeValue(forKey: keyPath)
+                }
                 customSetter(
-                    O.cs_fromRaw(object: rawObject),
-                    { (userValue: V?) -> Void in
-                        
-                        rawObject.setValue(
-                            userValue,
-                            forKvcKey: keyPath,
-                            willSetValue: { $0?.cs_toQueryableNativeType() }
-                        )
-                    },
+                    PartialObject<O>(rawObject),
                     (newValue as! V.QueryableNativeType?).flatMap(V.cs_fromQueryableNativeType)
                 )
             }
@@ -473,8 +460,8 @@ public enum ValueContainer<O: CoreStoreObject> {
         
         // MARK: Private
         
-        private let customGetter: ((_ `self`: O, _ getValue: () -> V?) -> V?)?
-        private let customSetter: ((_ `self`: O, _ setValue: (V?) -> Void, _ newValue: V?) -> Void)?
+        private let customGetter: ((_ partialObject: PartialObject<O>) -> V?)?
+        private let customSetter: ((_ partialObject: PartialObject<O>, _ newValue: V?) -> Void)?
     }
 }
 
@@ -484,7 +471,8 @@ public extension ValueContainer.Required where V: EmptyableAttributeType {
      Initializes the metadata for the property. This convenience initializer uses the `EmptyableAttributeType`'s "empty" value as the initial value for the property when the object is first created (e.g. `false` for `Bool`, `0` for `Int`, `""` for `String`, etc.)
      ```
      class Person: CoreStoreObject {
-         let title = Value.Required<String>("title") // initial value defaults to empty string
+         let title = Value.Required<String>("title", default: "Mr.") // explicit default value
+         let name = Value.Required<String>("name") // initial value defaults to empty string
      }
      ```
      - parameter keyPath: the permanent attribute name for this property.
@@ -492,13 +480,8 @@ public extension ValueContainer.Required where V: EmptyableAttributeType {
      - parameter isTransient: `true` if the property is transient, otherwise `false`. Defaults to `false` if not specified. The transient flag specifies whether or not a property's value is ignored when an object is saved to a persistent store. Transient properties are not saved to the persistent store, but are still managed for undo, redo, validation, and so on.
      - parameter versionHashModifier: used to mark or denote a property as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
      - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
-     - parameter customGetter: use this closure to make final transformations to the property's value before returning from the getter.
-     - parameter self: the `CoreStoreObject`
-     - parameter getValue: the original getter for the property
-     - parameter customSetter: use this closure to make final transformations to the new value before assigning to the property.
-     - parameter setValue: the original setter for the property
-     - parameter finalNewValue: the transformed new value
-     - parameter originalNewValue: the original new value
+     - parameter customGetter: use this closure as an "override" for the default property getter. The closure receives a `PartialObject<O>`, which acts as a fast, type-safe KVC interface for `CoreStoreObject`. The reason a `CoreStoreObject` instance is not passed directly is because the Core Data runtime is not aware of `CoreStoreObject` properties' static typing, and so loading those info everytime KVO invokes this accessor method incurs a cumulative performance hit (especially in KVO-heavy operations such as `ListMonitor` observing.) When accessing the property value from `PartialObject<O>`, make sure to use `PartialObject<O>.primitiveValue(for:)` instead of `PartialObject<O>.value(for:)`, which would unintentionally execute the same closure again recursively.
+     - parameter customSetter: use this closure as an "override" for the default property setter. The closure receives a `PartialObject<O>`, which acts as a fast, type-safe KVC interface for `CoreStoreObject`. The reason a `CoreStoreObject` instance is not passed directly is because the Core Data runtime is not aware of `CoreStoreObject` properties' static typing, and so loading those info everytime KVO invokes this accessor method incurs a cumulative performance hit (especially in KVO-heavy operations such as `ListMonitor` observing.) When accessing the property value from `PartialObject<O>`, make sure to use `PartialObject<O>.setPrimitiveValue(_:for:)` instead of `PartialObject<O>.setValue(_:for:)`, which would unintentionally execute the same closure again recursively.
      - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
      */
     public convenience init(
@@ -507,8 +490,8 @@ public extension ValueContainer.Required where V: EmptyableAttributeType {
         isTransient: Bool = false,
         versionHashModifier: String? = nil,
         renamingIdentifier: String? = nil,
-        customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)? = nil,
-        customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void)? = nil,
+        customGetter: ((_ partialObject: PartialObject<O>) -> V)? = nil,
+        customSetter: ((_ partialObject: PartialObject<O>, _ newValue: V) -> Void)? = nil,
         affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
         
         self.init(
@@ -559,7 +542,30 @@ public enum TransformableContainer<O: CoreStoreObject> {
          Initializes the metadata for the property.
          ```
          class Animal: CoreStoreObject {
-             let color = Transformable.Optional<UIColor>("color")
+             let species = Value.Required<String>("species")
+             let color = Transformable.Required<UIColor>(
+                 "color",
+                 default: UIColor.clear,
+                 isTransient: true,
+                 customGetter: Animal.getColor(_:)
+             )
+         }
+         
+         private static func getColor(_ partialObject: PartialObject<Animal>) -> UIColor {
+             let cachedColor = partialObject.primitiveValue(for: { $0.color })
+             if cachedColor != UIColor.clear {
+         
+                 return cachedColor
+             }
+             let color: UIColor
+             switch partialObject.value(for: { $0.species }) {
+         
+             case "Swift": color = UIColor.orange
+             case "Bulbasaur": color = UIColor.green
+             default: color = UIColor.black
+             }
+             partialObject.setPrimitiveValue(color, for: { $0.color })
+             return color
          }
          ```
          - parameter keyPath: the permanent attribute name for this property.
@@ -568,13 +574,8 @@ public enum TransformableContainer<O: CoreStoreObject> {
          - parameter isTransient: `true` if the property is transient, otherwise `false`. Defaults to `false` if not specified. The transient flag specifies whether or not a property's value is ignored when an object is saved to a persistent store. Transient properties are not saved to the persistent store, but are still managed for undo, redo, validation, and so on.
          - parameter versionHashModifier: used to mark or denote a property as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
          - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
-         - parameter customGetter: use this closure to make final transformations to the property's value before returning from the getter.
-         - parameter self: the `CoreStoreObject`
-         - parameter getValue: the original getter for the property
-         - parameter customSetter: use this closure to make final transformations to the new value before assigning to the property.
-         - parameter setValue: the original setter for the property
-         - parameter finalNewValue: the transformed new value
-         - parameter originalNewValue: the original new value
+         - parameter customGetter: use this closure as an "override" for the default property getter. The closure receives a `PartialObject<O>`, which acts as a fast, type-safe KVC interface for `CoreStoreObject`. The reason a `CoreStoreObject` instance is not passed directly is because the Core Data runtime is not aware of `CoreStoreObject` properties' static typing, and so loading those info everytime KVO invokes this accessor method incurs a cumulative performance hit (especially in KVO-heavy operations such as `ListMonitor` observing.) When accessing the property value from `PartialObject<O>`, make sure to use `PartialObject<O>.primitiveValue(for:)` instead of `PartialObject<O>.value(for:)`, which would unintentionally execute the same closure again recursively.
+         - parameter customSetter: use this closure as an "override" for the default property setter. The closure receives a `PartialObject<O>`, which acts as a fast, type-safe KVC interface for `CoreStoreObject`. The reason a `CoreStoreObject` instance is not passed directly is because the Core Data runtime is not aware of `CoreStoreObject` properties' static typing, and so loading those info everytime KVO invokes this accessor method incurs a cumulative performance hit (especially in KVO-heavy operations such as `ListMonitor` observing.) When accessing the property value from `PartialObject<O>`, make sure to use `PartialObject<O>.setPrimitiveValue(_:for:)` instead of `PartialObject<O>.setValue(_:for:)`, which would unintentionally execute the same closure again recursively.
          - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
          */
         public init(
@@ -584,8 +585,8 @@ public enum TransformableContainer<O: CoreStoreObject> {
             isTransient: Bool = false,
             versionHashModifier: String? = nil,
             renamingIdentifier: String? = nil,
-            customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)? = nil,
-            customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void)? = nil,
+            customGetter: ((_ partialObject: PartialObject<O>) -> V)? = nil,
+            customSetter: ((_ partialObject: PartialObject<O>, _ newValue: V) -> Void)? = nil,
             affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
             
             self.keyPath = keyPath
@@ -616,17 +617,11 @@ public enum TransformableContainer<O: CoreStoreObject> {
                         object.rawObject!.isRunningInAllowedQueue() == true,
                         "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
                     )
-                    let customGetter = (self.customGetter ?? { $1() })
-                    return customGetter(
-                        object,
-                        { () -> V in
-                            
-                            return object.rawObject!.getValue(
-                                forKvcKey: self.keyPath,
-                                didGetValue: { $0 as! V }
-                            )
-                        }
-                    )
+                    if let customGetter = self.customGetter {
+                        
+                        return customGetter(PartialObject<O>(object.rawObject!))
+                    }
+                    return object.rawObject!.value(forKey: self.keyPath)! as! V
                 }
             }
             set {
@@ -642,20 +637,16 @@ public enum TransformableContainer<O: CoreStoreObject> {
                         "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
                     )
                     CoreStore.assert(
-                        self.isTransient || object.rawObject!.isEditableInContext() == true,
+                        object.rawObject!.isEditableInContext() == true,
                         "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
                     )
-                    let customSetter = (self.customSetter ?? { $1($2) })
-                    customSetter(
-                        object,
-                        { (newValue: V) -> Void in
-                            
-                            object.rawObject!.setValue(
-                                newValue,
-                                forKvcKey: self.keyPath
-                            )
-                        },
-                        newValue
+                    if let customSetter = self.customSetter {
+                        
+                        return customSetter(PartialObject<O>(object.rawObject!), newValue)
+                    }
+                    object.rawObject!.setValue(
+                        newValue,
+                        forKey: self.keyPath
                     )
                 }
             }
@@ -690,10 +681,13 @@ public enum TransformableContainer<O: CoreStoreObject> {
             return { (_ id: Any) -> Any? in
                 
                 let rawObject = id as! CoreStoreManagedObject
-                return customGetter(
-                    O.cs_fromRaw(object: rawObject),
-                    { rawObject.getValue(forKvcKey: keyPath) as! V }
-                )
+                rawObject.willAccessValue(forKey: keyPath)
+                defer {
+                    
+                    rawObject.didAccessValue(forKey: keyPath)
+                }
+                let value = customGetter(PartialObject<O>(rawObject))
+                return value
             }
         }
         
@@ -707,12 +701,13 @@ public enum TransformableContainer<O: CoreStoreObject> {
             return { (_ id: Any, _ newValue: Any?) -> Void in
                 
                 let rawObject = id as! CoreStoreManagedObject
+                rawObject.willChangeValue(forKey: keyPath)
+                defer {
+                    
+                    rawObject.didChangeValue(forKey: keyPath)
+                }
                 customSetter(
-                    O.cs_fromRaw(object: rawObject),
-                    { (userValue: V) -> Void in
-                        
-                        rawObject.setValue(userValue, forKvcKey: keyPath)
-                    },
+                    PartialObject<O>(rawObject),
                     newValue as! V
                 )
             }
@@ -721,8 +716,8 @@ public enum TransformableContainer<O: CoreStoreObject> {
         
         // MARK: Private
         
-        private let customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)?
-        private let customSetter: ((_ `self`: O, _ setValue: (V) -> Void, _ newValue: V) -> Void)?
+        private let customGetter: ((_ partialObject: PartialObject<O>) -> V)?
+        private let customSetter: ((_ partialObject: PartialObject<O>, _ newValue: V) -> Void)?
     }
     
     
@@ -745,7 +740,27 @@ public enum TransformableContainer<O: CoreStoreObject> {
          Initializes the metadata for the property.
          ```
          class Animal: CoreStoreObject {
-            let color = Transformable.Optional<UIColor>("color")
+             let species = Value.Required<String>("species")
+             let color = Transformable.Optional<UIColor>(
+                 "color",
+                 isTransient: true,
+                 customGetter: Animal.getColor(_:)
+             )
+         }
+             
+         private static func getColor(_ partialObject: PartialObject<Animal>) -> UIColor? {
+             if let cachedColor = partialObject.primitiveValue(for: { $0.color }) {
+                 return cachedColor
+             }
+             let color: UIColor?
+             switch partialObject.value(for: { $0.species }) {
+             
+             case "Swift": color = UIColor.orange
+             case "Bulbasaur": color = UIColor.green
+             default: return nil
+             }
+             partialObject.setPrimitiveValue(color, for: { $0.color })
+             return color
          }
          ```
          - parameter keyPath: the permanent attribute name for this property.
@@ -754,13 +769,8 @@ public enum TransformableContainer<O: CoreStoreObject> {
          - parameter isTransient: `true` if the property is transient, otherwise `false`. Defaults to `false` if not specified. The transient flag specifies whether or not a property's value is ignored when an object is saved to a persistent store. Transient properties are not saved to the persistent store, but are still managed for undo, redo, validation, and so on.
          - parameter versionHashModifier: used to mark or denote a property as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
          - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
-         - parameter customGetter: use this closure to make final transformations to the property's value before returning from the getter.
-         - parameter self: the `CoreStoreObject`
-         - parameter getValue: the original getter for the property
-         - parameter customSetter: use this closure to make final transformations to the new value before assigning to the property.
-         - parameter setValue: the original setter for the property
-         - parameter finalNewValue: the transformed new value
-         - parameter originalNewValue: the original new value
+         - parameter customGetter: use this closure as an "override" for the default property getter. The closure receives a `PartialObject<O>`, which acts as a fast, type-safe KVC interface for `CoreStoreObject`. The reason a `CoreStoreObject` instance is not passed directly is because the Core Data runtime is not aware of `CoreStoreObject` properties' static typing, and so loading those info everytime KVO invokes this accessor method incurs a cumulative performance hit (especially in KVO-heavy operations such as `ListMonitor` observing.) When accessing the property value from `PartialObject<O>`, make sure to use `PartialObject<O>.primitiveValue(for:)` instead of `PartialObject<O>.value(for:)`, which would unintentionally execute the same closure again recursively.
+         - parameter customSetter: use this closure as an "override" for the default property setter. The closure receives a `PartialObject<O>`, which acts as a fast, type-safe KVC interface for `CoreStoreObject`. The reason a `CoreStoreObject` instance is not passed directly is because the Core Data runtime is not aware of `CoreStoreObject` properties' static typing, and so loading those info everytime KVO invokes this accessor method incurs a cumulative performance hit (especially in KVO-heavy operations such as `ListMonitor` observing.) When accessing the property value from `PartialObject<O>`, make sure to use `PartialObject<O>.setPrimitiveValue(_:for:)` instead of `PartialObject<O>.setValue(_:for:)`, which would unintentionally execute the same closure again recursively.
          - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
          */
         public init(
@@ -770,8 +780,8 @@ public enum TransformableContainer<O: CoreStoreObject> {
             isTransient: Bool = false,
             versionHashModifier: String? = nil,
             renamingIdentifier: String? = nil,
-            customGetter: ((_ `self`: O, _ getValue: () -> V?) -> V?)? = nil,
-            customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V?) -> Void, _ originalNewValue: V?) -> Void)? = nil,
+            customGetter: ((_ partialObject: PartialObject<O>) -> V?)? = nil,
+            customSetter: ((_ partialObject: PartialObject<O>, _ newValue: V?) -> Void)? = nil,
             affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
             
             self.keyPath = keyPath
@@ -802,17 +812,11 @@ public enum TransformableContainer<O: CoreStoreObject> {
                         object.rawObject!.isRunningInAllowedQueue() == true,
                         "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
                     )
-                    let customGetter = (self.customGetter ?? { $1() })
-                    return customGetter(
-                        object,
-                        { () -> V? in
-                            
-                            return object.rawObject!.getValue(
-                                forKvcKey: self.keyPath,
-                                didGetValue: { $0 as! V? }
-                            )
-                        }
-                    )
+                    if let customGetter = self.customGetter {
+                        
+                        return customGetter(PartialObject<O>(object.rawObject!))
+                    }
+                    return object.rawObject!.value(forKey: self.keyPath) as! V?
                 }
             }
             set {
@@ -828,20 +832,16 @@ public enum TransformableContainer<O: CoreStoreObject> {
                         "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
                     )
                     CoreStore.assert(
-                        self.isTransient || object.rawObject!.isEditableInContext() == true,
+                        object.rawObject!.isEditableInContext() == true,
                         "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
                     )
-                    let customSetter = (self.customSetter ?? { $1($2) })
-                    customSetter(
-                        object,
-                        { (newValue: V?) -> Void in
-                            
-                            object.rawObject!.setValue(
-                                newValue,
-                                forKvcKey: self.keyPath
-                            )
-                        },
-                        newValue
+                    if let customSetter = self.customSetter {
+                        
+                        return customSetter(PartialObject<O>(object.rawObject!), newValue)
+                    }
+                    object.rawObject!.setValue(
+                        newValue,
+                        forKey: self.keyPath
                     )
                 }
             }
@@ -876,37 +876,33 @@ public enum TransformableContainer<O: CoreStoreObject> {
             return { (_ id: Any) -> Any? in
                 
                 let rawObject = id as! CoreStoreManagedObject
-                return customGetter(
-                    O.cs_fromRaw(object: rawObject),
-                    { rawObject.getValue(forKvcKey: keyPath) as! V? }
-                )
+                rawObject.willAccessValue(forKey: keyPath)
+                defer {
+                    
+                    rawObject.didAccessValue(forKey: keyPath)
+                }
+                let value = customGetter(PartialObject<O>(rawObject))
+                return value
             }
         }
         
         internal private(set) lazy var setter: CoreStoreManagedObject.CustomSetter? = cs_lazy { [unowned self] in
             
-            let keyPath = self.keyPath
             guard let customSetter = self.customSetter else {
                 
-                guard let _ = self.customGetter else {
-                    
-                    return nil
-                }
-                return { (_ id: Any, _ newValue: Any?) -> Void in
-                    
-                    let rawObject = id as! CoreStoreManagedObject
-                    rawObject.setValue(newValue, forKvcKey: keyPath)
-                }
+                return nil
             }
+            let keyPath = self.keyPath
             return { (_ id: Any, _ newValue: Any?) -> Void in
                 
                 let rawObject = id as! CoreStoreManagedObject
+                rawObject.willChangeValue(forKey: keyPath)
+                defer {
+                    
+                    rawObject.didChangeValue(forKey: keyPath)
+                }
                 customSetter(
-                    O.cs_fromRaw(object: rawObject),
-                    { (userValue: V?) -> Void in
-                        
-                        rawObject.setValue(userValue, forKvcKey: keyPath)
-                    },
+                    PartialObject<O>(rawObject),
                     newValue as! V?
                 )
             }
@@ -915,8 +911,8 @@ public enum TransformableContainer<O: CoreStoreObject> {
         
         // MARK: Private
         
-        private let customGetter: ((_ `self`: O, _ getValue: () -> V?) -> V?)?
-        private let customSetter: ((_ `self`: O, _ setValue: (V?) -> Void, _ newValue: V?) -> Void)?
+        private let customGetter: ((_ partialObject: PartialObject<O>) -> V?)?
+        private let customSetter: ((_ partialObject: PartialObject<O>, _ newValue: V?) -> Void)?
     }
 }