Add async operations and pagination completion (#50)

CHANGELOG.md

@@ -2,6 +2,12 @@
 All notable changes to this project will be documented in this file.
 `FetchRequests` adheres to [Semantic Versioning](https://semver.org/).
 
+## 6.1.0
+Release TBD
+
+* Adds async operations for fetch and resort
+* Adds completion closure to performPagination, with a boolean value indicating if values were returned or not  
+
 ## [6.0.3](https://github.com/square/FetchRequests/releases/tag/6.0.3)
 Released on 2024-03-06
 
@@ -17,7 +23,7 @@ Released on 2023-06-23
 
 * The demo now includes a SwiftUI example
 * Fix for SwiftUI when a FetchDefinition request is synchronous
-
+    
 ## [6.0](https://github.com/square/FetchRequests/releases/tag/6.0.0)
 Released on 2023-04-05
 

FetchRequests/Sources/Controller/FetchedResultsController.swift

@@ -238,7 +238,8 @@ public class FetchedResultsController<FetchedObject: FetchableObject>: NSObject,
         return new
     }
 
-    private let debounceInsertsAndReloads: Bool
+    internal let debounceInsertsAndReloads: Bool
+
     private var objectsToReload: Set<FetchedObject> = []
     private var objectsToInsert: OrderedSet<FetchedObject> = []
 

FetchRequests/Sources/Controller/FetchedResultsControllerProtocol.swift

@@ -48,6 +48,28 @@ public protocol FetchedResultsControllerProtocol<FetchedObject>: DoublyObservabl
     func indexPath(for object: FetchedObject) -> IndexPath?
 }
 
+// MARK: - Async
+
+public extension FetchedResultsControllerProtocol {
+    @MainActor
+    func performFetch() async {
+        await withCheckedContinuation { continuation in
+            performFetch {
+                continuation.resume()
+            }
+        }
+    }
+
+    @MainActor
+    func resort(using newSortDescriptors: [NSSortDescriptor]) async {
+        await withCheckedContinuation { continuation in
+            resort(using: sortDescriptors) {
+                continuation.resume()
+            }
+        }
+    }
+}
+
 // MARK: - Index Paths
 
 public extension FetchedResultsControllerProtocol {

FetchRequests/Sources/Controller/PausableFetchedResultsController.swift

@@ -174,6 +174,10 @@ extension PausableFetchedResultsController: FetchedResultsControllerProtocol {
     public var sections: [Section] {
         sectionsSnapshot ?? controller.sections
     }
+
+    internal var debounceInsertsAndReloads: Bool {
+        controller.debounceInsertsAndReloads
+    }
 }
 
 // MARK: - InternalFetchResultsControllerProtocol

FetchRequests/Sources/Requests/PaginatingFetchDefinition.swift

@@ -41,16 +41,29 @@ public class PaginatingFetchDefinition<FetchedObject: FetchableObject>: FetchDef
 private extension InternalFetchResultsControllerProtocol {
     @MainActor
     func performPagination(
-        with paginationRequest: PaginatingFetchDefinition<FetchedObject>.PaginationRequest
+        with paginationRequest: PaginatingFetchDefinition<FetchedObject>.PaginationRequest,
+        willDebounceInsertsAndReloads: Bool,
+        completion: @escaping @MainActor (_ hasPageResults: Bool) -> Void
     ) {
         let currentResults = self.fetchedObjects
         paginationRequest(currentResults) { [weak self] pageResults in
             guard let pageResults else {
+                completion(false)
                 return
             }
+
             performOnMainThread {
                 self?.manuallyInsert(objects: pageResults, emitChanges: true)
             }
+
+            if willDebounceInsertsAndReloads {
+                // force this to run on the _next_ run loop, at which point any debounced insertions should have happened
+                DispatchQueue.main.async {
+                    completion(!pageResults.isEmpty)
+                }
+            } else {
+                completion(!pageResults.isEmpty)
+            }
         }
     }
 }
@@ -77,8 +90,21 @@ public class PaginatingFetchedResultsController<
     }
 
     @MainActor
-    public func performPagination() {
-        performPagination(with: paginatingDefinition.paginationRequest)
+    public func performPagination(completion: @escaping @MainActor (_ hasPageResults: Bool) -> Void = { _ in }) {
+        performPagination(
+            with: paginatingDefinition.paginationRequest,
+            willDebounceInsertsAndReloads: debounceInsertsAndReloads,
+            completion: completion
+        )
+    }
+
+    @MainActor
+    public func performPagination() async -> Bool {
+        await withCheckedContinuation { continuation in
+            performPagination { hasPageResults in
+                continuation.resume(returning: hasPageResults)
+            }
+        }
     }
 }
 
@@ -105,6 +131,10 @@ public class PausablePaginatingFetchedResultsController<
 
     @MainActor
     public func performPagination() {
-        performPagination(with: paginatingDefinition.paginationRequest)
+        performPagination(
+            with: paginatingDefinition.paginationRequest,
+            willDebounceInsertsAndReloads: debounceInsertsAndReloads,
+            completion: { _ in }
+        )
     }
 }

FetchRequests/Tests/Controllers/PaginatingFetchedResultsControllerTestCase.swift

@@ -17,7 +17,9 @@ class PaginatingFetchedResultsControllerTestCase: XCTestCase, FetchedResultsCont
     private(set) var fetchCompletion: (([TestObject]) -> Void)!
 
     private var paginationCurrentResults: [TestObject]!
-    private var paginationCompletion: (([TestObject]?) -> Void)!
+    private var paginationRequestCompletion: (([TestObject]?) -> Void)!
+
+    private var performPaginationCompletionResult: Bool!
 
     private var associationRequest: TestObject.AssociationRequest!
 
@@ -35,7 +37,7 @@ class PaginatingFetchedResultsControllerTestCase: XCTestCase, FetchedResultsCont
         }
         let paginationRequest: PaginatingFetchDefinition<TestObject>.PaginationRequest = { [unowned self] currentResults, completion in
             self.paginationCurrentResults = currentResults
-            self.paginationCompletion = completion
+            self.paginationRequestCompletion = completion
         }
 
         let desiredAssociations = TestObject.fetchRequestAssociations(
@@ -72,7 +74,8 @@ class PaginatingFetchedResultsControllerTestCase: XCTestCase, FetchedResultsCont
         controller = nil
         fetchCompletion = nil
         paginationCurrentResults = nil
-        paginationCompletion = nil
+        paginationRequestCompletion = nil
+        performPaginationCompletionResult = nil
         associationRequest = nil
         inclusionCheck = nil
 
@@ -124,7 +127,8 @@ class PaginatingFetchedResultsControllerTestCase: XCTestCase, FetchedResultsCont
 
         fetchCompletion = nil
         paginationCurrentResults = nil
-        paginationCompletion = nil
+        paginationRequestCompletion = nil
+        performPaginationCompletionResult = nil
         changeEvents.removeAll()
 
         // Trigger pagination
@@ -133,6 +137,8 @@ class PaginatingFetchedResultsControllerTestCase: XCTestCase, FetchedResultsCont
 
         performPagination(paginationObjectIDs)
 
+        XCTAssertTrue(performPaginationCompletionResult)
+
         XCTAssertEqual(controller.sections.count, 1)
         XCTAssertEqual(controller.sections[0].fetchedIDs, objectIDs + paginationObjectIDs)
 
@@ -161,7 +167,8 @@ class PaginatingFetchedResultsControllerTestCase: XCTestCase, FetchedResultsCont
 
         fetchCompletion = nil
         paginationCurrentResults = nil
-        paginationCompletion = nil
+        paginationRequestCompletion = nil
+        performPaginationCompletionResult = nil
         changeEvents.removeAll()
 
         // Trigger pagination
@@ -170,9 +177,12 @@ class PaginatingFetchedResultsControllerTestCase: XCTestCase, FetchedResultsCont
 
         performPagination(paginationObjectIDs)
 
+        XCTAssertTrue(performPaginationCompletionResult)
+
         fetchCompletion = nil
         paginationCurrentResults = nil
-        paginationCompletion = nil
+        paginationRequestCompletion = nil
+        performPaginationCompletionResult = nil
         changeEvents.removeAll()
 
         // Trigger insert
@@ -184,7 +194,7 @@ class PaginatingFetchedResultsControllerTestCase: XCTestCase, FetchedResultsCont
 
         XCTAssertNil(fetchCompletion)
         XCTAssertNil(paginationCurrentResults)
-        XCTAssertNil(paginationCompletion)
+        XCTAssertNil(paginationRequestCompletion)
 
         XCTAssertEqual(controller.sections.count, 1)
         XCTAssertEqual(controller.sections[0].fetchedIDs, ["a", "b", "c", "d", "e", "f"])
@@ -193,6 +203,71 @@ class PaginatingFetchedResultsControllerTestCase: XCTestCase, FetchedResultsCont
         XCTAssertEqual(changeEvents[0].change, FetchedResultsChange.insert(location: IndexPath(item: 4, section: 0)))
         XCTAssertEqual(changeEvents[0].object.id, "e")
     }
+
+    func testPaginationHasObjects() async throws {
+        controller = PaginatingFetchedResultsController(
+            definition: createFetchDefinition(),
+            debounceInsertsAndReloads: false
+        )
+        controller.setDelegate(self)
+
+        // Fetch some objects
+
+        let objectIDs = ["a", "b", "c"]
+
+        try performFetch(objectIDs)
+
+        fetchCompletion = nil
+        paginationCurrentResults = nil
+        paginationRequestCompletion = nil
+        performPaginationCompletionResult = nil
+        changeEvents.removeAll()
+
+        // Trigger pagination
+
+        let paginationObjectIDs = ["d", "f"]
+
+        performPagination(paginationObjectIDs)
+
+        XCTAssertTrue(performPaginationCompletionResult)
+
+        XCTAssertEqual(controller.sections.count, 1)
+        XCTAssertEqual(controller.sections[0].fetchedIDs, objectIDs + paginationObjectIDs)
+
+        XCTAssertEqual(changeEvents.count, 2)
+        XCTAssertEqual(changeEvents[0].change, FetchedResultsChange.insert(location: IndexPath(item: 3, section: 0)))
+        XCTAssertEqual(changeEvents[0].object.id, "d")
+        XCTAssertEqual(changeEvents[1].change, FetchedResultsChange.insert(location: IndexPath(item: 4, section: 0)))
+        XCTAssertEqual(changeEvents[1].object.id, "f")
+    }
+
+    func testPaginationDoesNotHaveObjects() async throws {
+        controller = PaginatingFetchedResultsController(
+            definition: createFetchDefinition(),
+            debounceInsertsAndReloads: false
+        )
+        controller.setDelegate(self)
+
+        // Fetch some objects
+
+        let objectIDs = ["a", "b", "c"]
+
+        try performFetch(objectIDs)
+
+        fetchCompletion = nil
+        paginationCurrentResults = nil
+        paginationRequestCompletion = nil
+        performPaginationCompletionResult = nil
+        changeEvents.removeAll()
+
+        // Trigger pagination
+
+        let paginationObjectIDs: [String] = []
+
+        performPagination(paginationObjectIDs)
+
+        XCTAssertFalse(performPaginationCompletionResult)
+    }
 }
 
 // MARK: - FetchedResultsControllerDelegate
@@ -217,9 +292,11 @@ private extension PaginatingFetchedResultsControllerTestCase {
     }
 
     func performPagination(_ objects: [TestObject], file: StaticString = #file, line: UInt = #line) {
-        controller.performPagination()
+        controller.performPagination { hasPageResults in
+            self.performPaginationCompletionResult = hasPageResults
+        }
 
-        self.paginationCompletion(objects)
+        self.paginationRequestCompletion(objects)
 
         let hasAllObjects = objects.allSatisfy { controller.fetchedObjects.contains($0) }
         XCTAssertTrue(hasAllObjects, file: file, line: line)