Files
CoreStore/Sources/LiveObject.swift
2019-10-16 19:20:11 +09:00

358 lines
9.0 KiB
Swift

//
// LiveObject.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.
//
import CoreData
#if canImport(Combine)
import Combine
#endif
#if canImport(SwiftUI)
import SwiftUI
#endif
// MARK: - LiveObject
@dynamicMemberLookup
public final class LiveObject<O: DynamicObject>: ObjectRepresentation, Hashable {
// MARK: Public
public typealias SectionID = String
public typealias ItemID = O.ObjectID
public var snapshot: SnapshotType {
return self.lazySnapshot
}
public func addObserver<T: AnyObject>(_ observer: T, _ callback: @escaping (LiveObject<O>) -> Void) {
self.observers.setObject(
Internals.Closure(callback),
forKey: observer
)
}
public func removeObserver<T: AnyObject>(_ observer: T) {
self.observers.removeObject(forKey: observer)
}
deinit {
self.observers.removeAllObjects()
}
// MARK: ObjectRepresentation
public typealias ObjectType = O
public func objectID() -> O.ObjectID {
return self.id
}
public func asLiveObject(in dataStack: DataStack) -> LiveObject<O>? {
let context = dataStack.unsafeContext()
if self.context == context {
return self
}
return Self.init(objectID: self.id, context: context)
}
public func asReadOnly(in dataStack: DataStack) -> O? {
return dataStack.unsafeContext().fetchExisting(self.id)
}
public func asEditable(in transaction: BaseDataTransaction) -> O? {
return transaction.unsafeContext().fetchExisting(self.id)
}
public func asSnapshot(in dataStack: DataStack) -> ObjectSnapshot<O>? {
let context = dataStack.unsafeContext()
if self.context == context {
return self.lazySnapshot
}
return .init(objectID: self.id, context: context)
}
public func asSnapshot(in transaction: BaseDataTransaction) -> ObjectSnapshot<O>? {
let context = transaction.unsafeContext()
if self.context == context {
return self.lazySnapshot
}
return .init(objectID: self.id, context: context)
}
// MARK: Equatable
public static func == (_ lhs: LiveObject, _ rhs: LiveObject) -> Bool {
return lhs.id == rhs.id
&& lhs.context == rhs.context
}
// MARK: Hashable
public func hash(into hasher: inout Hasher) {
hasher.combine(self.id)
hasher.combine(self.context)
}
// MARK: LiveResult
public typealias SnapshotType = ObjectSnapshot<O>
// MARK: Internal
internal convenience init(objectID: O.ObjectID, context: NSManagedObjectContext) {
self.init(
objectID: objectID,
context: context,
initializer: ObjectSnapshot<O>.init(objectID:context:)
)
}
// MARK: FilePrivate
fileprivate let rawObjectWillChange: Any?
fileprivate init(objectID: O.ObjectID, context: NSManagedObjectContext, initializer: @escaping (NSManagedObjectID, NSManagedObjectContext) -> ObjectSnapshot<O>) {
self.id = objectID
self.context = context
if #available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *) {
#if canImport(Combine)
self.rawObjectWillChange = ObservableObjectPublisher()
#else
self.rawObjectWillChange = nil
#endif
}
else {
self.rawObjectWillChange = nil
}
self.$lazySnapshot.initialize({ initializer(objectID, context) })
context.objectsDidChangeObserver(for: self).addObserver(self) { [weak self] (objectIDs) in
guard let self = self else {
return
}
self.willChange()
self.$lazySnapshot.reset({ initializer(objectID, context) })
self.notifyObservers()
self.didChange()
}
}
fileprivate var object: O {
return self.context.fetchExisting(self.id)!
}
// MARK: Private
private let id: O.ObjectID
private let context: NSManagedObjectContext
@Internals.LazyNonmutating(uninitialized: ())
private var lazySnapshot: ObjectSnapshot<O>
private lazy var observers: NSMapTable<AnyObject, Internals.Closure<LiveObject<O>, Void>> = .weakToStrongObjects()
private func notifyObservers() {
guard let enumerator = self.observers.objectEnumerator() else {
return
}
for closure in enumerator {
(closure as! Internals.Closure<LiveObject
<O>, Void>).invoke(with: self)
}
}
}
#if canImport(Combine)
import Combine
@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
extension LiveObject: ObservableObject {}
#endif
// MARK: - LiveObject: LiveResult
extension LiveObject: LiveResult {
// MARK: ObservableObject
#if canImport(Combine)
@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
public var objectWillChange: ObservableObjectPublisher {
return self.rawObjectWillChange! as! ObservableObjectPublisher
}
#endif
public func willChange() {
guard #available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *) else {
return
}
#if canImport(Combine)
#if canImport(SwiftUI)
withAnimation {
self.objectWillChange.send()
}
#endif
self.objectWillChange.send()
#endif
}
public func didChange() {
// TODO:
}
}
// MARK: - LiveObject where O: NSManagedObject
@available(*, unavailable, message: "KeyPaths accessed from @dynamicMemberLookup types can't generate KVC keys yet (https://bugs.swift.org/browse/SR-11351)")
extension LiveObject where O: NSManagedObject {
// MARK: Public
/**
Returns the value for the property identified by a given key.
*/
public subscript<V: AllowedObjectiveCKeyPathValue>(dynamicMember member: KeyPath<O, V>) -> V {
fatalError()
// return self.snapshot[dynamicMember: member]
}
}
// MARK: - LiveObject where O: CoreStoreObject
extension LiveObject where O: CoreStoreObject {
// MARK: Public
/**
Returns the value for the property identified by a given key.
*/
public subscript<V>(dynamicMember member: KeyPath<O, ValueContainer<O>.Required<V>>) -> V {
return self.snapshot[dynamicMember: member]
}
/**
Returns the value for the property identified by a given key.
*/
public subscript<V>(dynamicMember member: KeyPath<O, ValueContainer<O>.Optional<V>>) -> V? {
return self.snapshot[dynamicMember: member]
}
/**
Returns the value for the property identified by a given key.
*/
public subscript<V>(dynamicMember member: KeyPath<O, TransformableContainer<O>.Required<V>>) -> V {
return self.snapshot[dynamicMember: member]
}
/**
Returns the value for the property identified by a given key.
*/
public subscript<V>(dynamicMember member: KeyPath<O, TransformableContainer<O>.Optional<V>>) -> V? {
return self.snapshot[dynamicMember: member]
}
/**
Returns the value for the property identified by a given key.
*/
public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToOne<D>>) -> D? {
return self.snapshot[dynamicMember: member]
}
/**
Returns the value for the property identified by a given key.
*/
public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyOrdered<D>>) -> [D] {
return self.snapshot[dynamicMember: member]
}
/**
Returns the value for the property identified by a given key.
*/
public subscript<D>(dynamicMember member: KeyPath<O, RelationshipContainer<O>.ToManyUnordered<D>>) -> Set<D> {
return self.snapshot[dynamicMember: member]
}
}