SwiftUI and Combine utilities appledocs. Bump up to 8.0 and iOS 11.0/macOS 10.13

Sources/ObjectPublisher+Reactive.swift

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+//
+//  ObjectPublisher+Reactive.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.
+//
+
+#if canImport(Combine)
+
+import Combine
+
+
+// MARK: - ObjectPublisher
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension ObjectPublisher {
+    
+    // MARK: Public
+    
+    /**
+     Combine utilities for the `ObjectPublisher` are exposed through this namespace
+     */
+    public var reactive: ObjectPublisher.ReactiveNamespace {
+        
+        return .init(self)
+    }
+    
+    
+    // MARK: - ReactiveNamespace
+    
+    /**
+     Combine utilities for the `ObjectPublisher` are exposed through this namespace. Extend this type if you need to add other Combine Publisher utilities for `ObjectPublisher`.
+     */
+    @dynamicMemberLookup
+    public struct ReactiveNamespace {
+        
+        // MARK: Public
+        
+        /**
+         The `ObjectPublisher` instance
+         */
+        public let base: ObjectPublisher
+        
+        
+        // MARK: Internal
+        
+        internal init(_ base: ObjectPublisher) {
+            
+            self.base = base
+        }
+    }
+}
+
+
+// MARK: - ObjectPublisher.ReactiveNamespace
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension ObjectPublisher.ReactiveNamespace {
+
+    // MARK: Public
+    
+    /**
+     Returns a `Publisher` that emits an `ObjectSnapshot?` whenever changes occur in the `ObjectPublisher`. The event emits `nil` if the object has been deletd.
+     ```
+     objectPublisher.reactive
+         .snapshot(emitInitialValue: true)
+         .sink(
+             receiveCompletion: { result in
+                 // ...
+             },
+             receiveValue: { (objectSnapshot) in
+                 tableViewCell.setObject(objectSnapshot)
+             }
+         )
+         .store(in: &tableViewCell.cancellables)
+     ```
+     - parameter emitInitialValue: If `true`, the current value is immediately emitted to the first subscriber. If `false`, the event fires only starting the next `ObjectSnapshot` update.
+     - returns: A `Publisher` that emits an `ObjectSnapshot?` whenever changes occur in the `ObjectPublisher`. The event emits `nil` if the object has been deletd.
+     */
+    public func snapshot(emitInitialValue: Bool = true) -> ObjectPublisher.SnapshotPublisher {
+        
+        return .init(
+            objectPublisher: self.base,
+            emitInitialValue: emitInitialValue
+        )
+    }
+}
+
+
+// MARK: - ObjectPublisher.ReactiveNamespace where O: NSManagedObject
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension ObjectPublisher.ReactiveNamespace where O: NSManagedObject {
+
+    /**
+     Returns the value for the property identified by a given key.
+     */
+    public subscript<V: AllowedObjectiveCKeyPathValue>(dynamicMember member: KeyPath<O, V>) -> some Publisher {
+
+        return self
+            .snapshot(emitInitialValue: true)
+            .map({ $0?[dynamicMember: member] })
+    }
+}
+
+
+// MARK: - ObjectPublisher.ReactiveNamespace where O: CoreStoreObject
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension ObjectPublisher.ReactiveNamespace where O: CoreStoreObject {
+
+    /**
+     Returns the value for the property identified by a given key.
+     */
+    public subscript<OBase, V>(dynamicMember member: KeyPath<O, FieldContainer<OBase>.Stored<V>>) -> some Publisher {
+        
+        return self
+            .snapshot(emitInitialValue: true)
+            .map({ $0?[dynamicMember: member] })
+    }
+
+    /**
+     Returns the value for the property identified by a given key.
+     */
+    public subscript<OBase, V>(dynamicMember member: KeyPath<O, FieldContainer<OBase>.Virtual<V>>) -> some Publisher {
+        
+        return self
+            .snapshot(emitInitialValue: true)
+            .map({ $0?[dynamicMember: member] })
+    }
+
+    /**
+     Returns the value for the property identified by a given key.
+     */
+    public subscript<OBase, V>(dynamicMember member: KeyPath<O, FieldContainer<OBase>.Coded<V>>) -> some Publisher {
+        
+        return self
+            .snapshot(emitInitialValue: true)
+            .map({ $0?[dynamicMember: member] })
+    }
+}
+
+#endif