duckduckgo · samsymons · Nov 17, 2021 · Oct 23, 2021 · Oct 23, 2021
diff --git a/Core/Database.swift b/Core/Database.swift
@@ -30,8 +30,8 @@ public class Database {
 
     public static let shared = Database()
 
-    private let semaphore = DispatchSemaphore(value: 0)
     private let container: NSPersistentContainer
+    private let storeLoadedCondition = RunLoop.ResumeCondition()
 
     public var isDatabaseFileInitialized: Bool {
         var containerURL = DDGPersistentContainer.defaultDirectoryURL()
@@ -77,17 +77,17 @@ public class Database {
             context.name = "Migration"
             context.perform {
                 handler(context)
-                self.semaphore.signal()
+                self.storeLoadedCondition.resolve()
             }
         }
     }
 
     public func makeContext(concurrencyType: NSManagedObjectContextConcurrencyType, name: String? = nil) -> NSManagedObjectContext {
-        semaphore.wait()
+        RunLoop.current.run(until: storeLoadedCondition)
+
         let context = NSManagedObjectContext(concurrencyType: concurrencyType)
         context.persistentStoreCoordinator = container.persistentStoreCoordinator
         context.name = name
-        semaphore.signal()
 
         return context
     }

diff --git a/DuckDuckGo.xcodeproj/project.pbxproj b/DuckDuckGo.xcodeproj/project.pbxproj
@@ -39,6 +39,8 @@
 		4B62C4BA25B930DD008912C6 /* AppConfigurationFetchTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B62C4B925B930DD008912C6 /* AppConfigurationFetchTests.swift */; };
 		4B75EA9226A266CB00018634 /* PrintingUserScript.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B75EA9126A266CB00018634 /* PrintingUserScript.swift */; };
 		4B82E98025B634B800656FE7 /* TrackerRadarKit in Frameworks */ = {isa = PBXBuildFile; productRef = 4B82E97F25B634B800656FE7 /* TrackerRadarKit */; };
+		4BC21A2B2723862E00229F0E /* RunLoopExtension.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4BC21A29272384F500229F0E /* RunLoopExtension.swift */; };
+		4BC21A2F27238B7500229F0E /* RunLoopExtensionTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4BC21A2C272388BD00229F0E /* RunLoopExtensionTests.swift */; };
 		4BDCECB92680333100F5C244 /* EmailWaitlistWebViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4BDCECB82680333100F5C244 /* EmailWaitlistWebViewController.swift */; };
 		4BE86C5D2633DBD8001C0E77 /* BrowserServicesKit in Frameworks */ = {isa = PBXBuildFile; productRef = 4BE86C5C2633DBD8001C0E77 /* BrowserServicesKit */; };
 		83004E802193BB8200DA013C /* WKNavigationExtension.swift in Sources */ = {isa = PBXBuildFile; fileRef = 83004E7F2193BB8200DA013C /* WKNavigationExtension.swift */; };
@@ -731,6 +733,8 @@
 		4B60ACA0252EC0B100E8D219 /* FullScreenVideoUserScript.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FullScreenVideoUserScript.swift; sourceTree = "<group>"; };
 		4B62C4B925B930DD008912C6 /* AppConfigurationFetchTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppConfigurationFetchTests.swift; sourceTree = "<group>"; };
 		4B75EA9126A266CB00018634 /* PrintingUserScript.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PrintingUserScript.swift; sourceTree = "<group>"; };
+		4BC21A29272384F500229F0E /* RunLoopExtension.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; name = RunLoopExtension.swift; path = ../DuckDuckGo/RunLoopExtension.swift; sourceTree = "<group>"; };
+		4BC21A2C272388BD00229F0E /* RunLoopExtensionTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RunLoopExtensionTests.swift; sourceTree = "<group>"; };
 		4BDCECB82680333100F5C244 /* EmailWaitlistWebViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EmailWaitlistWebViewController.swift; sourceTree = "<group>"; };
 		6FB030C7234331B400A10DB9 /* Configuration.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; name = Configuration.xcconfig; path = Configuration/Configuration.xcconfig; sourceTree = "<group>"; };
 		83004E7F2193BB8200DA013C /* WKNavigationExtension.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WKNavigationExtension.swift; sourceTree = "<group>"; };
@@ -3247,6 +3251,7 @@
 				98982B3322F8D8E400578AC9 /* Debounce.swift */,
 				1CB7B82023CEA1F800AA24EA /* DateExtension.swift */,
 				85449EFA23FDA0BC00512AAF /* UserDefaultsPropertyWrapper.swift */,
+				4BC21A29272384F500229F0E /* RunLoopExtension.swift */,
 			);
 			name = Utilities;
 			sourceTree = "<group>";
@@ -3461,6 +3466,7 @@
 				83C05D04212C74600068712A /* BloomFilterWrapperTest.swift */,
 				8341D804212D5DFB000514C2 /* HashExtensionTest.swift */,
 				1CB7B82223CEA28300AA24EA /* DateExtensionTests.swift */,
+				4BC21A2C272388BD00229F0E /* RunLoopExtensionTests.swift */,
 			);
 			name = Utilities;
 			sourceTree = "<group>";
@@ -4692,6 +4698,7 @@
 				8528AE7E212EF5FF00D0BD74 /* AppRatingPromptTests.swift in Sources */,
 				85C9E5F521B422D300460EBC /* BookmarksManagerTests.swift in Sources */,
 				981FED692201FE69008488D7 /* AutoClearSettingsScreenTests.swift in Sources */,
+				4BC21A2F27238B7500229F0E /* RunLoopExtensionTests.swift in Sources */,
 				851B1283221FE65E004781BC /* ImproveOnboardingExperiment1Tests.swift in Sources */,
 				F14513591F4664E900710C46 /* SiteRatingTests.swift in Sources */,
 				F194FAFB1F14E622009B4DF8 /* UIFontExtensionTests.swift in Sources */,
@@ -4822,6 +4829,7 @@
 				85C271DF1FD044D7007216B4 /* HTTPSUpgradeStore.swift in Sources */,
 				830381C01F850AAF00863075 /* WKWebViewConfigurationExtension.swift in Sources */,
 				85B718F51FD071E50031A14F /* HTTPSUpgrade.xcdatamodeld in Sources */,
+				4BC21A2B2723862E00229F0E /* RunLoopExtension.swift in Sources */,
 				85CA53AA24BB376800A6288C /* NotFoundCachingDownloader.swift in Sources */,
 				4B60ACA1252EC0B100E8D219 /* FullScreenVideoUserScript.swift in Sources */,
 				F1A886781F29394E0096251E /* WebCacheManager.swift in Sources */,

diff --git a/DuckDuckGo/RunLoopExtension.swift b/DuckDuckGo/RunLoopExtension.swift
@@ -0,0 +1,94 @@
+//
+//  RunLoopExtension.swift
+//  DuckDuckGo
+//
+//  Copyright © 2021 DuckDuckGo. All rights reserved.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+
+import Foundation
+
+extension RunLoop {
+
+    final class ResumeCondition {
+
+        private let lock = NSLock()
+        private var receivePorts = [Port]()
+
+        private var _isResolved = false
+        var isResolved: Bool {
+            lock.lock()
+            defer { lock.unlock() }
+            return _isResolved
+        }
+
+        init() {
+        }
+
+        convenience init(dispatchGroup: DispatchGroup) {
+            self.init()
+            dispatchGroup.notify(queue: .main) {
+                self.resolve()
+            }
+        }
+
+        func addPort(to runLoop: RunLoop, forMode mode: RunLoop.Mode) -> Port? {
+            lock.lock()
+            defer { lock.unlock() }
+            guard !_isResolved else { return nil }
+
+            let port = Port()
+            receivePorts.append(port)
+            runLoop.add(port, forMode: mode)
+
+            return port
+        }
+
+        func resolve(mode: RunLoop.Mode = .default) {
+            lock.lock()
+
+            assert(!_isResolved)
+            _isResolved = true
+
+            let ports = receivePorts
+
+            lock.unlock()
+
+            let sendPort = Port()
+            RunLoop.current.add(sendPort, forMode: mode)
+
+            // Send Wake message from current RunLoop port to each running RunLoop
+            for receivePort in ports {
+                receivePort.send(before: Date(), components: nil, from: sendPort, reserved: 0)
+            }
+
+            RunLoop.current.remove(sendPort, forMode: mode)
+        }
+
+    }
+
+    func run(mode: RunLoop.Mode = .default, until condition: ResumeCondition) {
+        // Add port to current RunLoop to receive Wake message
+        guard let port = condition.addPort(to: self, forMode: mode) else {
+            // already resolved
+            return
+        }
+
+        while !condition.isResolved {
+            self.run(mode: mode, before: .distantFuture)
+        }
+        self.remove(port, forMode: mode)
+    }
+
+}
diff --git a/DuckDuckGoTests/DateExtensionTests.swift b/DuckDuckGoTests/DateExtensionTests.swift
@@ -19,24 +19,24 @@
 
 import XCTest
 
- class DateExtensionTests: XCTestCase {
+class DateExtensionTests: XCTestCase {
 
-     func testWhenDatesAreSame() {
+    func testWhenDatesAreSame() {
         let today: Date = Date()
         let secondDate: Date = Date()
         XCTAssertTrue(today.isSameDay(secondDate))
     }
 
-     func testWhenDatesAreNotSame() {
+    func testWhenDatesAreNotSame() {
         let today: Date = Date()
         let secondDate: Date? = Calendar.current.date(byAdding: .day, value: -1, to: today)
         XCTAssertFalse(today.isSameDay(secondDate))
     }
-
-     func testWhenOtherDateIsNil() {
+    
+    func testWhenOtherDateIsNil() {
         let today: Date = Date()
         let secondDate: Date? = nil
         XCTAssertFalse(today.isSameDay(secondDate))
     }
 
- }
+}
diff --git a/DuckDuckGoTests/RunLoopExtensionTests.swift b/DuckDuckGoTests/RunLoopExtensionTests.swift
@@ -0,0 +1,131 @@
+//
+//  RunLoopExtensionTests.swift
+//  DuckDuckGo
+//
+//  Copyright © 2021 DuckDuckGo. All rights reserved.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+
+import Foundation
+import XCTest
+@testable import Core
+
+class RunLoopExtensionTests: XCTestCase {
+
+    func testWhenConditionResolvedThenNoWaitIsPerformed() {
+        let condition = RunLoop.ResumeCondition()
+        condition.resolve()
+
+        let e = expectation(description: "should execute after wait")
+        var isExecuted = false
+        RunLoop.current.perform {
+            isExecuted = true
+            e.fulfill()
+        }
+
+        RunLoop.current.run(until: condition)
+        XCTAssertFalse(isExecuted)
+
+        waitForExpectations(timeout: 1)
+    }
+
+    func testWhenConditionIsResolvedThenWaitIsFinished() {
+        let condition = RunLoop.ResumeCondition()
+
+        let e = expectation(description: "should execute")
+        RunLoop.current.perform {
+            condition.resolve()
+            e.fulfill()
+        }
+
+        RunLoop.current.run(until: condition)
+        waitForExpectations(timeout: 0)
+    }
+
+    func testWhenDispatchGroupIsEmptyThenNoWaitIsPerformed() {
+        let dispatchGroup = DispatchGroup()
+        let condition = RunLoop.ResumeCondition(dispatchGroup: dispatchGroup)
+
+        let e = expectation(description: "should execute")
+        RunLoop.current.perform {
+            e.fulfill()
+        }
+
+        RunLoop.current.run(until: condition)
+        waitForExpectations(timeout: 0)
+    }
+
+    func testWhenDispatchGroupIsCompleteThenWaitIsFinished() {
+        let dispatchGroup = DispatchGroup()
+        let condition = RunLoop.ResumeCondition(dispatchGroup: dispatchGroup)
+
+        let e = expectation(description: "should execute")
+        RunLoop.current.perform {
+            e.fulfill()
+        }
+
+        for _ in 0..<3 {
+            dispatchGroup.enter()
+            DispatchQueue.global().asyncAfter(deadline: .now() + 0.05) {
+                dispatchGroup.leave()
+            }
+        }
+
+        RunLoop.current.run(until: condition)
+        waitForExpectations(timeout: 0)
+    }
+
+    func testWhenNestedWaitIsCalledThenWaitIsPerformed() {
+        let condition = RunLoop.ResumeCondition()
+
+        let e = expectation(description: "should execute")
+        RunLoop.current.perform {
+            RunLoop.current.perform {
+                condition.resolve()
+                e.fulfill()
+            }
+            RunLoop.current.run(until: condition)
+        }
+
+        RunLoop.current.run(until: condition)
+        waitForExpectations(timeout: 0)
+    }
+
+    func testWhenResolveFromBackgroundThreadThenWaitIsFinished() {
+        let condition = RunLoop.ResumeCondition()
+
+        DispatchQueue.global().asyncAfter(deadline: .now() + 0.05) {
+            condition.resolve()
+        }
+
+        RunLoop.current.run(until: condition)
+    }
+
+    func testWhenWaitingInBackgroundThreadThenWaitIsFinishedWhenResolved() {
+        let condition = RunLoop.ResumeCondition()
+
+        let e = expectation(description: "should execute")
+        DispatchQueue.global().async {
+            RunLoop.current.run(until: condition)
+            e.fulfill()
+        }
+        DispatchQueue.global().asyncAfter(deadline: .now() + 0.05) {
+            condition.resolve()
+        }
+
+        RunLoop.current.run(until: condition)
+        waitForExpectations(timeout: 1)
+    }
+
+}