Improves error handling when fetching multiple sources

Fetching sources is no longer all or nothing. Now if a source cannot be fetched, it won’t prevent other sources from being updated.

AltStore.xcodeproj/project.pbxproj

@@ -159,6 +159,7 @@
 		BF770E6922BD57DD002A40FE /* Silence.m4a in Resources */ = {isa = PBXBuildFile; fileRef = BF770E6822BD57DD002A40FE /* Silence.m4a */; };
 		BF7C627223DBB3B400515A2D /* AltStore2ToAltStore3.xcmappingmodel in Sources */ = {isa = PBXBuildFile; fileRef = BF7C627123DBB3B400515A2D /* AltStore2ToAltStore3.xcmappingmodel */; };
 		BF7C627423DBB78C00515A2D /* InstalledAppPolicy.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF7C627323DBB78C00515A2D /* InstalledAppPolicy.swift */; };
+		BF88F97224F8727D00BB75DF /* AppManagerErrors.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF88F97124F8727D00BB75DF /* AppManagerErrors.swift */; };
 		BF8CAE452489E772004D6CCE /* AnisetteDataManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF8CAE422489E772004D6CCE /* AnisetteDataManager.swift */; };
 		BF8CAE462489E772004D6CCE /* AppManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF8CAE432489E772004D6CCE /* AppManager.swift */; };
 		BF8CAE472489E772004D6CCE /* RequestHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF8CAE442489E772004D6CCE /* RequestHandler.swift */; };
@@ -525,6 +526,7 @@
 		BF7C627023DBB33300515A2D /* AltStore 3.xcdatamodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcdatamodel; path = "AltStore 3.xcdatamodel"; sourceTree = "<group>"; };
 		BF7C627123DBB3B400515A2D /* AltStore2ToAltStore3.xcmappingmodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcmappingmodel; path = AltStore2ToAltStore3.xcmappingmodel; sourceTree = "<group>"; };
 		BF7C627323DBB78C00515A2D /* InstalledAppPolicy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InstalledAppPolicy.swift; sourceTree = "<group>"; };
+		BF88F97124F8727D00BB75DF /* AppManagerErrors.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppManagerErrors.swift; sourceTree = "<group>"; };
 		BF8CAE422489E772004D6CCE /* AnisetteDataManager.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AnisetteDataManager.swift; sourceTree = "<group>"; };
 		BF8CAE432489E772004D6CCE /* AppManager.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AppManager.swift; sourceTree = "<group>"; };
 		BF8CAE442489E772004D6CCE /* RequestHandler.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RequestHandler.swift; sourceTree = "<group>"; };
@@ -1211,6 +1213,7 @@
 			isa = PBXGroup;
 			children = (
 				BF0C4EBC22A1BD8B009A2DD7 /* AppManager.swift */,
+				BF88F97124F8727D00BB75DF /* AppManagerErrors.swift */,
 			);
 			path = "Managing Apps";
 			sourceTree = "<group>";
@@ -2069,6 +2072,7 @@
 				BF100C50232D7CD1006A8926 /* AltStoreToAltStore2.xcmappingmodel in Sources */,
 				BF3D64B022E8D4B800E9056B /* AppContentViewControllerCells.swift in Sources */,
 				BFC57A6E2416FC5D00EB891E /* InstalledAppsCollectionHeaderView.swift in Sources */,
+				BF88F97224F8727D00BB75DF /* AppManagerErrors.swift in Sources */,
 				BF6C8FAE2429597900125131 /* BannerCollectionViewCell.swift in Sources */,
 				BFBBE2DD22931B20002097FA /* AltStore.xcdatamodeld in Sources */,
 				BF56D2AA23DF88310006506D /* AppID.swift in Sources */,

AltStore/AppDelegate.swift

@@ -302,13 +302,11 @@ private extension AppDelegate
         dispatchGroup.enter()
         
         AppManager.shared.fetchSources() { (result) in
-            fetchSourcesResult = result
+            fetchSourcesResult = result.map { $0.0 }.mapError { $0 as Error }
             
             do
             {
-                let sources = try result.get()
+                let (_, context) = try result.get()
-                
-                guard let context = sources.first?.managedObjectContext else { return }
                 
                 let previousUpdatesFetchRequest = InstalledApp.updatesFetchRequest() as! NSFetchRequest<NSFetchRequestResult>
                 previousUpdatesFetchRequest.includesPendingChanges = false

AltStore/Browse/BrowseViewController.swift

@@ -178,20 +178,26 @@ private extension BrowseViewController
         AppManager.shared.fetchSources() { (result) in
             do
             {
-                let sources = try result.get()
+                do
-                try sources.first?.managedObjectContext?.save()
+                {
+                    let (_, context) = try result.get()
+                    try context.save()
                     
                     DispatchQueue.main.async {
                         self.loadingState = .finished(.success(()))
                     }
                 }
-            catch let error as NSError
+                catch let error as AppManager.FetchSourcesError
+                {
+                    try error.managedObjectContext?.save()
+                    throw error
+                }
+            }
+            catch
             {
                 DispatchQueue.main.async {
                     if self.dataSource.itemCount > 0
                     {
-                        let error = error.withLocalizedFailure(NSLocalizedString("Failed to Fetch Sources", comment: ""))
-                        
                         let toastView = ToastView(error: error)
                         toastView.show(in: self)
                     }

AltStore/Components/ToastView.swift

@@ -77,7 +77,7 @@ class ToastView: RSTToastView
         else
         {
             text = error.localizedDescription
-            detailText = underlyingError?.localizedDescription
+            detailText = underlyingError?.localizedDescription ?? error.localizedRecoverySuggestion
         }
         
         self.init(text: text, detailText: detailText)

AltStore/Managing Apps/AppManager.swift

@@ -197,15 +197,16 @@ extension AppManager
         self.run([fetchSourceOperation], context: nil)
     }
     
-    func fetchSources(completionHandler: @escaping (Result<Set<Source>, Error>) -> Void)
+    func fetchSources(completionHandler: @escaping (Result<(Set<Source>, NSManagedObjectContext), FetchSourcesError>) -> Void)
     {
         DatabaseManager.shared.persistentContainer.performBackgroundTask { (context) in
             let sources = Source.all(in: context)
-            guard !sources.isEmpty else { return completionHandler(.failure(OperationError.noSources)) }
+            guard !sources.isEmpty else { return completionHandler(.failure(.init(OperationError.noSources))) }
             
             let dispatchGroup = DispatchGroup()
             var fetchedSources = Set<Source>()
-            var error: Error?
+            
+            var errors = [Source: Error]()
             
             let managedObjectContext = DatabaseManager.shared.persistentContainer.newBackgroundContext()
             
@@ -216,8 +217,10 @@ extension AppManager
                 fetchSourceOperation.resultHandler = { (result) in
                     switch result
                     {
-                    case .failure(let e): error = e
                     case .success(let source): fetchedSources.insert(source)
+                    case .failure(let error):
+                        let source = managedObjectContext.object(with: source.objectID) as! Source
+                        errors[source] = error
                     }
                     
                     dispatchGroup.leave()
@@ -227,14 +230,15 @@ extension AppManager
             }
             
             dispatchGroup.notify(queue: .global()) {
-                if let error = error
+                managedObjectContext.perform {
+                    if !errors.isEmpty
                     {
-                    completionHandler(.failure(error))
+                        let sources = Set(sources.compactMap { managedObjectContext.object(with: $0.objectID) as? Source })
+                        completionHandler(.failure(.init(sources: sources, errors: errors, context: managedObjectContext)))
                     }
                     else
                     {
-                    managedObjectContext.perform {
+                        completionHandler(.success((fetchedSources, managedObjectContext)))
-                        completionHandler(.success(fetchedSources))
                     }
                 }
                 

AltStore/Managing Apps/AppManagerErrors.swift

@@ -0,0 +1,84 @@
+//
+//  AppManagerErrors.swift
+//  AltStore
+//
+//  Created by Riley Testut on 8/27/20.
+//  Copyright © 2020 Riley Testut. All rights reserved.
+//
+
+import Foundation
+import CoreData
+
+extension AppManager
+{
+    struct FetchSourcesError: LocalizedError, CustomNSError
+    {
+        var primaryError: Error?
+        
+        var sources: Set<Source>?
+        var errors = [Source: Error]()
+        
+        var managedObjectContext: NSManagedObjectContext?
+        
+        var errorDescription: String? {
+            if let error = self.primaryError
+            {
+                return error.localizedDescription
+            }
+            else
+            {
+                var localizedDescription: String?
+                
+                self.managedObjectContext?.performAndWait {
+                    if self.sources?.count == 1
+                    {
+                        localizedDescription = NSLocalizedString("Could not refresh store.", comment: "")
+                    }
+                    else if self.errors.count == 1
+                    {
+                        guard let source = self.errors.keys.first else { return }
+                        localizedDescription = String(format: NSLocalizedString("Could not refresh source “%@”.", comment: ""), source.name)
+                    }
+                    else
+                    {
+                        localizedDescription = String(format: NSLocalizedString("Could not refresh %@ sources.", comment: ""), NSNumber(value: self.errors.count))
+                    }
+                }
+                
+                return localizedDescription
+            }
+        }
+        
+        var recoverySuggestion: String? {
+            if let error = self.primaryError as NSError?
+            {
+                return error.localizedRecoverySuggestion
+            }
+            else if self.errors.count == 1
+            {
+                return nil
+            }
+            else
+            {
+                return NSLocalizedString("Tap to view source errors.", comment: "")
+            }
+        }
+        
+        var errorUserInfo: [String : Any] {
+            guard let error = self.errors.values.first, self.errors.count == 1 else { return [:] }
+            return [NSUnderlyingErrorKey: error]
+        }
+        
+        init(_ error: Error)
+        {
+            self.primaryError = error
+        }
+        
+        init(sources: Set<Source>, errors: [Source: Error], context: NSManagedObjectContext)
+        {
+            self.sources = sources
+            self.errors = errors
+            self.managedObjectContext = context
+        }
+    }
+}

AltStore/Model/AppPermission.swift

@@ -67,15 +67,25 @@ class AppPermission: NSManagedObject, Decodable, Fetchable
     {
         guard let context = decoder.managedObjectContext else { preconditionFailure("Decoder must have non-nil NSManagedObjectContext.") }
         
-        super.init(entity: AppPermission.entity(), insertInto: nil)
+        super.init(entity: AppPermission.entity(), insertInto: context)
         
+        do
+        {
             let container = try decoder.container(keyedBy: CodingKeys.self)
             self.usageDescription = try container.decode(String.self, forKey: .usageDescription)
             
             let rawType = try container.decode(String.self, forKey: .type)
             self.type = ALTAppPermissionType(rawValue: rawType)
+        }
+        catch
+        {
+            if let context = self.managedObjectContext
+            {
+                context.delete(self)
+            }
             
-        context.insert(self)
+            throw error
+        }
     }
 }
 

AltStore/Model/Source.swift

@@ -88,8 +88,10 @@ class Source: NSManagedObject, Fetchable, Decodable
         guard let context = decoder.managedObjectContext else { preconditionFailure("Decoder must have non-nil NSManagedObjectContext.") }
         guard let sourceURL = decoder.sourceURL else { preconditionFailure("Decoder must have non-nil sourceURL.") }
         
-        super.init(entity: Source.entity(), insertInto: nil)
+        super.init(entity: Source.entity(), insertInto: context)
         
+        do
+        {
             self.sourceURL = sourceURL
             
             let container = try decoder.container(keyedBy: CodingKeys.self)
@@ -107,6 +109,7 @@ class Source: NSManagedObject, Fetchable, Decodable
                 app.sourceIdentifier = self.identifier
                 app.sortIndex = Int32(index)
             }
+            self._apps = NSMutableOrderedSet(array: apps)
             
             let newsItems = try container.decodeIfPresent([NewsItem].self, forKey: .news) ?? []
             for (index, item) in newsItems.enumerated()
@@ -115,8 +118,6 @@ class Source: NSManagedObject, Fetchable, Decodable
                 item.sortIndex = Int32(index)
             }
                                 
-        context.insert(self)
-                
             for newsItem in newsItems
             {
                 guard let appID = newsItem.appID else { continue }
@@ -130,11 +131,18 @@ class Source: NSManagedObject, Fetchable, Decodable
                     newsItem.storeApp = nil
                 }
             }
-        
-        // Must assign after we're inserted into context.
-        self._apps = NSMutableOrderedSet(array: apps)
             self._newsItems = NSMutableOrderedSet(array: newsItems)
         }
+        catch
+        {
+            if let context = self.managedObjectContext
+            {
+                context.delete(self)
+            }
+            
+            throw error
+        }
+    }
 }
 
 extension Source

AltStore/Model/StoreApp.swift

@@ -104,8 +104,11 @@ class StoreApp: NSManagedObject, Decodable, Fetchable
     {
         guard let context = decoder.managedObjectContext else { preconditionFailure("Decoder must have non-nil NSManagedObjectContext.") }
         
-        super.init(entity: StoreApp.entity(), insertInto: nil)
+        // Must initialize with context in order for child context saves to work correctly.
+        super.init(entity: StoreApp.entity(), insertInto: context)
         
+        do
+        {
             let container = try decoder.container(keyedBy: CodingKeys.self)
             self.name = try container.decode(String.self, forKey: .name)
             self.bundleIdentifier = try container.decode(String.self, forKey: .bundleIdentifier)
@@ -136,12 +139,18 @@ class StoreApp: NSManagedObject, Decodable, Fetchable
             self.isBeta = try container.decodeIfPresent(Bool.self, forKey: .isBeta) ?? false
             
             let permissions = try container.decodeIfPresent([AppPermission].self, forKey: .permissions) ?? []
-        
-        context.insert(self)
-        
-        // Must assign after we're inserted into context.
             self._permissions = NSOrderedSet(array: permissions)
         }
+        catch
+        {
+            if let context = self.managedObjectContext
+            {
+                context.delete(self)
+            }
+            
+            throw error
+        }
+    }
 }
 
 extension StoreApp

AltStore/News/NewsViewController.swift

@@ -177,20 +177,26 @@ private extension NewsViewController
         AppManager.shared.fetchSources() { (result) in
             do
             {
-                let sources = try result.get()
+                do
-                try sources.first?.managedObjectContext?.save()
+                {
+                    let (_, context) = try result.get()
+                    try context.save()
                     
                     DispatchQueue.main.async {
                         self.loadingState = .finished(.success(()))
                     }
                 }
-            catch let error as NSError
+                catch let error as AppManager.FetchSourcesError
+                {
+                    try error.managedObjectContext?.save()
+                    throw error
+                }
+            }
+            catch
             {
                 DispatchQueue.main.async {
                     if self.dataSource.itemCount > 0
                     {
-                        let error = error.withLocalizedFailure(NSLocalizedString("Failed to Fetch Sources", comment: ""))
-                        
                         let toastView = ToastView(error: error)
                         toastView.show(in: self)
                     }

AltStore/Operations/FetchSourceOperation.swift

@@ -41,7 +41,10 @@ class FetchSourceOperation: ResultOperation<Source>
         super.main()
         
         let dataTask = self.session.dataTask(with: self.sourceURL) { (data, response, error) in
-            self.managedObjectContext.perform {
+            
+            let childContext = DatabaseManager.shared.persistentContainer.newBackgroundContext(withParent: self.managedObjectContext)
+            childContext.mergePolicy = NSOverwriteMergePolicy
+            childContext.perform {
                 do
                 {
                     let (data, _) = try Result((data, response), error).get()
@@ -68,24 +71,38 @@ class FetchSourceOperation: ResultOperation<Source>
                         throw DecodingError.dataCorruptedError(in: container, debugDescription: "Date is in invalid format.")
                     })
                     
-                    decoder.managedObjectContext = self.managedObjectContext
+                    decoder.managedObjectContext = childContext
                     decoder.sourceURL = self.sourceURL
                     
                     let source = try decoder.decode(Source.self, from: data)
+                    let identifier = source.identifier
                     
-                    if source.identifier == Source.altStoreIdentifier, let patreonAccessToken = source.userInfo?[.patreonAccessToken]
+                    if identifier == Source.altStoreIdentifier, let patreonAccessToken = source.userInfo?[.patreonAccessToken]
                     {
                         Keychain.shared.patreonCreatorAccessToken = patreonAccessToken
                     }
                     
+                    try childContext.save()
+                    
+                    self.managedObjectContext.perform {
+                        if let source = Source.first(satisfying: NSPredicate(format: "%K == %@", #keyPath(Source.identifier), identifier), in: self.managedObjectContext)
+                        {
                             self.finish(.success(source))
                         }
+                        else
+                        {
+                            self.finish(.failure(OperationError.noSources))
+                        }
+                    }
+                }
                 catch
                 {
+                    self.managedObjectContext.perform {
                         self.finish(.failure(error))
                     }
                 }
             }
+        }
         
         self.progress.addChild(dataTask.progress, withPendingUnitCount: 1)