Sendable (#19)

SectionDataController is now sendable but updating from only main-actor.

Development/DataSources.xcodeproj/project.pbxproj

@@ -378,7 +378,7 @@
 				);
 				GENERATE_INFOPLIST_FILE = YES;
 				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 16.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -387,6 +387,7 @@
 				MARKETING_VERSION = 1.0.0;
 				PRODUCT_BUNDLE_IDENTIFIER = me.muukii.DataSourcesDemo;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = 1;
 			};
 			name = Debug;
@@ -403,7 +404,7 @@
 				);
 				GENERATE_INFOPLIST_FILE = YES;
 				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 16.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -412,6 +413,7 @@
 				MARKETING_VERSION = 1.0.0;
 				PRODUCT_BUNDLE_IDENTIFIER = me.muukii.DataSourcesDemo;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = 1;
 			};
 			name = Release;

Development/DataSourcesDemo/AppDelegate.swift

@@ -8,7 +8,7 @@
 
 import UIKit
 
-@UIApplicationMain
+@main
 class AppDelegate: UIResponder, UIApplicationDelegate {
 
   var window: UIWindow?

Development/DataSourcesDemo/Components.swift

@@ -44,6 +44,7 @@ struct ModelB: Model, Differentiable, Equatable {
   }
 }
 
+@MainActor
 final class ViewModel {
 
   let section0 = BehaviorRelay<[ModelA]>(value: [])
@@ -73,7 +74,7 @@ final class ViewModel {
     section0.modify {
       $0.removeFirst()
     }
-    DispatchQueue.global().async {
+    Task { @MainActor [self] in
       self.section0.modify {
         $0.append(ModelA(identity: UUID().uuidString, title: String.randomEmoji()))
       }
@@ -82,7 +83,7 @@ final class ViewModel {
     section1.modify {
       $0.removeFirst()
     }
-    DispatchQueue.global().async {
+    Task { @MainActor [self] in
       self.section1.modify {
         $0.append(ModelB(identity: UUID().uuidString, title: arc4random_uniform(30).description))
       }

Package.swift

@@ -1,9 +1,9 @@
-// swift-tools-version:5.5
+// swift-tools-version:6.0
 import PackageDescription
 
 let package = Package(
   name: "DataSources",
-  platforms: [.iOS(.v12)],
+  platforms: [.iOS(.v16)],
   products: [
     .library(name: "DataSources", targets: ["DataSources"]),
   ],

Sources/DataSources/SectionDataController.swift

@@ -7,14 +7,15 @@
 //
 
 import Foundation
+import os.atomic
+@preconcurrency import DifferenceKit
 
-import DifferenceKit
-
-public protocol SectionDataControllerType where AdapterType.Element == ItemType {
+public protocol SectionDataControllerType: Sendable where AdapterType.Element == ItemType {
 
   associatedtype ItemType : Differentiable
   associatedtype AdapterType : Updating
 
+  @MainActor
   func update(items: [ItemType], updateMode: SectionDataController<ItemType, AdapterType>.UpdateMode, immediately: Bool, completion: @escaping () -> Void)
 
   func asSectionDataController() -> SectionDataController<ItemType, AdapterType>
@@ -56,12 +57,12 @@ final class AnySectionDataController<A: Updating> {
 }
 
 /// DataSource for a section
-public final class SectionDataController<T: Differentiable, A: Updating>: SectionDataControllerType where A.Element == T {
+public final class SectionDataController<T: Differentiable & Sendable, A: Updating & Sendable>: Sendable, SectionDataControllerType where A.Element == T {
 
   public typealias ItemType = T
   public typealias AdapterType = A
 
-  public enum State {
+  public enum State: Sendable {
     case idle
     case updating
   }
@@ -72,18 +73,26 @@ public final class SectionDataController<T: Differentiable, A: Updating>: Sectio
   }
 
   // MARK: - Properties
+
+  public var items: [T] {
+    return _items.withLock { $0 }
+  }
+
+  public var snapshot: [T] {
+    return _snapshot.withLock { $0 }
+  }
 
-  private(set) public var items: [T] = []
+  private let _items: OSAllocatedUnfairLock<[T]> = .init(initialState: [])
 
-  private(set) public var snapshot: [T] = []
+  private let _snapshot: OSAllocatedUnfairLock<[T]> = .init(initialState: [])
 
-  private var state: State = .idle
+  private let state: OSAllocatedUnfairLock<State> = .init(initialState: .idle)
 
   private let throttle = Throttle(interval: 0.1)
 
   private let adapter: AdapterType
 
-  public internal(set) var displayingSection: Int
+  public let displayingSection: Int
 
   // MARK: - Initializers
 
@@ -113,8 +122,11 @@ public final class SectionDataController<T: Differentiable, A: Updating>: Sectio
   /// - Returns:
   public func item(at indexPath: IndexPath) -> T? {
     guard let index = toIndex(from: indexPath) else { return nil }
-    guard snapshot.indices.contains(index) else { return nil }
-    return snapshot[index]
+
+    return _snapshot.withLock {
+      guard $0.indices.contains(index) else { return nil }
+      return $0[index]
+    }
   }
 
   /// Reserves that a move occurred in DataSource by View operation.
@@ -137,9 +149,12 @@ public final class SectionDataController<T: Differentiable, A: Updating>: Sectio
       destinationIndexPath.section == displayingSection,
       "destinationIndexPath.section \(sourceIndexPath.section) must be equal to \(displayingSection)"
     )
+
+    _snapshot.withLock {
+      let o = $0.remove(at: sourceIndexPath.item)
+      $0.insert(o, at: destinationIndexPath.item)
+    }
 
-    let o = snapshot.remove(at: sourceIndexPath.item)
-    snapshot.insert(o, at: destinationIndexPath.item)
   }
 
   /// Update
@@ -152,40 +167,41 @@ public final class SectionDataController<T: Differentiable, A: Updating>: Sectio
   ///   - updateMode:
   ///   - immediately: False : indicate to throttled updating
   ///   - completion: 
+  @MainActor
   public func update(
     items: [T],
     updateMode: UpdateMode,
     immediately: Bool = false,
     completion: @escaping () -> Void
     ) {
-
-    self.items = items
-
-    let task = { [weak self] in
-      guard let `self` = self else { return }
-
-      let old = self.snapshot
-      let new = self.items
-
-      self.__update(
-        targetSection: self.displayingSection,
-        currentDisplayingItems: old,
-        newItems: new,
-        updateMode: updateMode,
-        completion: {
-          completion()
-      })
-    }
-
-    if immediately {
-      throttle.cancel()
-      task()
-    } else {
-      throttle.on {
+
+      self._items.withLock { $0 = items }
+
+      let task = { [weak self] in
+        guard let `self` = self else { return }
+
+        let old = self.snapshot
+        let new = self.items
+
+        self.__update(
+          targetSection: self.displayingSection,
+          currentDisplayingItems: old,
+          newItems: new,
+          updateMode: updateMode,
+          completion: {
+            completion()
+          })
+      }
+
+      if immediately {
+        throttle.cancel()
         task()
+      } else {
+        throttle.on {
+          task()
+        }
       }
-    }
-  }
+    }  
 
   public func asSectionDataController() -> SectionDataController<ItemType, AdapterType> {
     return self
@@ -208,26 +224,27 @@ public final class SectionDataController<T: Differentiable, A: Updating>: Sectio
     return indexPath.item
   }
 
+  @MainActor
   private func __update(
     targetSection: Int,
     currentDisplayingItems: [T],
     newItems: [T],
     updateMode: UpdateMode,
     completion: @escaping () -> Void
-    ) {
-
+  ) {
+    
     assertMainThread()
-
-    self.state = .updating
-
+    
+    self.state.withLock { $0 = .updating }
+    
     switch updateMode {
     case .everything:
 
-      self.snapshot = newItems
+      self._snapshot.withLock { $0 = newItems }
 
       adapter.reload {
         assertMainThread()
-        self.state = .idle
+        self.state.withLock { $0 = .idle }
         completion()
       }
 
@@ -258,7 +275,7 @@ public final class SectionDataController<T: Differentiable, A: Updating>: Sectio
 
         group.enter()
 
-        self.snapshot = changeset.data
+        self._snapshot.withLock { $0 = changeset.data }
 
         let updateContext = UpdateContext.init(
           diff: .init(diff: changeset, targetSection: targetSection),
@@ -299,7 +316,7 @@ public final class SectionDataController<T: Differentiable, A: Updating>: Sectio
       }
 
       group.notify(queue: .main) {
-        self.state = .idle
+        self.state.withLock { $0 = .idle }
         completion()
       }
 

Sources/DataSources/Throttle.swift

@@ -1,31 +1,24 @@
-//
-//  Throttle.swift
-//  DataSources
-//
-//  Created by muukii on 8/9/17.
-//  Copyright © 2017 muukii. All rights reserved.
-//
-
 import Foundation
 
+@MainActor
 final class Throttle {
-
+  
   private var timerReference: DispatchSourceTimer?
-
+  
   let interval: TimeInterval
   let queue: DispatchQueue
-
+  
   private var lastSendTime: Date?
-
-  init(interval: TimeInterval, queue: DispatchQueue = .main) {
+  
+  nonisolated init(interval: TimeInterval, queue: DispatchQueue = .main) {
     self.interval = interval
     self.queue = queue
   }
-
+  
   func on(handler: @escaping () -> Void) {
-
+    
     let now = Date()
-
+    
     if let _lastSendTime = lastSendTime {
       if (now.timeIntervalSinceReferenceDate - _lastSendTime.timeIntervalSinceReferenceDate) >= interval {
         handler()
@@ -34,14 +27,14 @@ final class Throttle {
     } else {
       lastSendTime = now
     }
-
+    
     let deadline = DispatchTime.now() + DispatchTimeInterval.milliseconds(Int(interval * 1000.0))
-
+    
     timerReference?.cancel()
-
+    
     let timer = DispatchSource.makeTimerSource(queue: queue)
     timer.schedule(deadline: deadline)
-
+    
     timer.setEventHandler(handler: { [weak timer, weak self] in
       self?.lastSendTime = nil
       handler()
@@ -52,7 +45,7 @@ final class Throttle {
 
     timerReference = timer
   }
-
+  
   func cancel() {
     timerReference = nil
   }

Sources/DataSources/Updating.swift

@@ -1,18 +1,11 @@
-//
-//  Updating.swift
-//  DataSources
-//
-//  Created by muukii on 8/7/17.
-//  Copyright © 2017 muukii. All rights reserved.
-//
 
 import Foundation
 
 import DifferenceKit
 
-public struct IndexPathDiff {
+public struct IndexPathDiff: Sendable {
 
-  public struct Move {
+  public struct Move : Sendable {
     let from: IndexPath
     let to: IndexPath
   }
@@ -53,7 +46,12 @@ public struct UpdateContext<Element> {
   }
 }
 
-public protocol Updating : class {
+extension UpdateContext: Sendable where Element: Sendable {
+}
+
+
+@MainActor
+public protocol Updating: AnyObject {
 
   associatedtype Target
   associatedtype Element