Adds BackupAppOperation to backup and restore app data

AltStore.xcodeproj/project.pbxproj

@@ -34,6 +34,7 @@
 		BF26A0E12370C5D400F53F9F /* ALTSourceUserInfoKey.m in Sources */ = {isa = PBXBuildFile; fileRef = BF26A0E02370C5D400F53F9F /* ALTSourceUserInfoKey.m */; };
 		BF29012F2318F6B100D88A45 /* AppBannerView.xib in Resources */ = {isa = PBXBuildFile; fileRef = BF29012E2318F6B100D88A45 /* AppBannerView.xib */; };
 		BF2901312318F7A800D88A45 /* AppBannerView.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF2901302318F7A800D88A45 /* AppBannerView.swift */; };
+		BF3432FB246B894F0052F4A1 /* BackupAppOperation.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF3432FA246B894F0052F4A1 /* BackupAppOperation.swift */; };
 		BF3BEFBF2408673400DE7D55 /* FetchProvisioningProfilesOperation.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF3BEFBE2408673400DE7D55 /* FetchProvisioningProfilesOperation.swift */; };
 		BF3BEFC124086A1E00DE7D55 /* RefreshAppOperation.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF3BEFC024086A1E00DE7D55 /* RefreshAppOperation.swift */; };
 		BF3D648822E79A3700E9056B /* AppPermission.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF3D648722E79A3700E9056B /* AppPermission.swift */; };
@@ -354,6 +355,7 @@
 		BF26A0E02370C5D400F53F9F /* ALTSourceUserInfoKey.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = ALTSourceUserInfoKey.m; sourceTree = "<group>"; };
 		BF29012E2318F6B100D88A45 /* AppBannerView.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = AppBannerView.xib; sourceTree = "<group>"; };
 		BF2901302318F7A800D88A45 /* AppBannerView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppBannerView.swift; sourceTree = "<group>"; };
+		BF3432FA246B894F0052F4A1 /* BackupAppOperation.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BackupAppOperation.swift; sourceTree = "<group>"; };
 		BF3BEFBE2408673400DE7D55 /* FetchProvisioningProfilesOperation.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FetchProvisioningProfilesOperation.swift; sourceTree = "<group>"; };
 		BF3BEFC024086A1E00DE7D55 /* RefreshAppOperation.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RefreshAppOperation.swift; sourceTree = "<group>"; };
 		BF3D648722E79A3700E9056B /* AppPermission.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppPermission.swift; sourceTree = "<group>"; };
@@ -1290,6 +1292,7 @@
 				BF56D2AB23DF8E170006506D /* FetchAppIDsOperation.swift */,
 				BFC57A642416C72400EB891E /* DeactivateAppOperation.swift */,
 				BFCCB519245E3401001853EA /* VerifyAppOperation.swift */,
+				BF3432FA246B894F0052F4A1 /* BackupAppOperation.swift */,
 			);
 			path = Operations;
 			sourceTree = "<group>";
@@ -1912,6 +1915,7 @@
 				BF3D648D22E79AC800E9056B /* ALTAppPermission.m in Sources */,
 				BFD5D6F2230DD974007955AB /* Benefit.swift in Sources */,
 				BFF0B6942321CB85007A79E1 /* AuthenticationViewController.swift in Sources */,
+				BF3432FB246B894F0052F4A1 /* BackupAppOperation.swift in Sources */,
 				BF9ABA4922DD0742008935CF /* ScreenshotCollectionViewCell.swift in Sources */,
 				BF9ABA4D22DD16DE008935CF /* PillButton.swift in Sources */,
 				BFE6326C22A86FF300F30809 /* AuthenticationOperation.swift in Sources */,

AltStore/AppDelegate.swift

@@ -55,7 +55,10 @@ extension AppDelegate
     static let openPatreonSettingsDeepLinkNotification = Notification.Name("com.rileytestut.AltStore.OpenPatreonSettingsDeepLinkNotification")
     static let importAppDeepLinkNotification = Notification.Name("com.rileytestut.AltStore.ImportAppDeepLinkNotification")
     
+    static let appBackupDidFinish = Notification.Name("com.rileytestut.AltStore.AppBackupDidFinish")
+    
     static let importAppDeepLinkURLKey = "fileURL"
+    static let appBackupResultKey = "result"
 }
 
 @UIApplicationMain
@@ -134,13 +137,43 @@ private extension AppDelegate
         else
         {
             guard let components = URLComponents(url: url, resolvingAgainstBaseURL: false) else { return false }
-            guard let host = components.host, host.lowercased() == "patreon" else { return false }
+            guard let host = components.host?.lowercased() else { return false }
             
-            DispatchQueue.main.async {
+            switch host
-                NotificationCenter.default.post(name: AppDelegate.openPatreonSettingsDeepLinkNotification, object: nil)
+            {
+            case "patreon":
+                DispatchQueue.main.async {
+                    NotificationCenter.default.post(name: AppDelegate.openPatreonSettingsDeepLinkNotification, object: nil)
+                }
+                
+                return true
+                
+            case "appbackupresponse":
+                let result: Result<Void, Error>
+                
+                switch url.path.lowercased()
+                {
+                case "/success": result = .success(())
+                case "/failure":
+                    let queryItems = components.queryItems?.reduce(into: [String: String]()) { $0[$1.name] = $1.value } ?? [:]
+                    guard
+                        let errorDomain = queryItems["errorDomain"],
+                        let errorCodeString = queryItems["errorCode"], let errorCode = Int(errorCodeString),
+                        let errorDescription = queryItems["errorDescription"]
+                    else { return false }
+                    
+                    let error = NSError(domain: errorDomain, code: errorCode, userInfo: [NSLocalizedDescriptionKey: errorDescription])
+                    result = .failure(error)
+                    
+                default: return false
+                }
+                
+                NotificationCenter.default.post(name: AppDelegate.appBackupDidFinish, object: nil, userInfo: [AppDelegate.appBackupResultKey: result])
+                
+                return true
+                
+            default: return false
             }
-            
-            return true
         }
     }
 }

AltStore/Operations/BackupAppOperation.swift

@@ -0,0 +1,183 @@
+//
+//  BackupAppOperation.swift
+//  AltStore
+//
+//  Created by Riley Testut on 5/12/20.
+//  Copyright © 2020 Riley Testut. All rights reserved.
+//
+
+import Foundation
+
+import AltKit
+import AltSign
+
+extension BackupAppOperation
+{
+    enum Action: String
+    {
+        case backup
+        case restore
+    }
+}
+
+@objc(BackupAppOperation)
+class BackupAppOperation: ResultOperation<Void>
+{
+    let action: Action
+    let context: InstallAppOperationContext
+    
+    private var appName: String?
+    private var timeoutTimer: Timer?
+    
+    init(action: Action, context: InstallAppOperationContext)
+    {
+        self.action = action
+        self.context = context
+        
+        super.init()
+    }
+    
+    override func main()
+    {
+        super.main()
+        
+        do
+        {
+            if let error = self.context.error
+            {
+                throw error
+            }
+            
+            guard let installedApp = self.context.installedApp, let context = installedApp.managedObjectContext else { throw OperationError.invalidParameters }
+            context.perform {
+                do
+                {
+                    let appName = installedApp.name
+                    self.appName = appName
+                    
+                    guard let altstoreApp = InstalledApp.fetchAltStore(in: context) else { throw OperationError.appNotFound }
+                    let altstoreOpenURL = altstoreApp.openAppURL
+                    
+                    var returnURLComponents = URLComponents(url: altstoreOpenURL, resolvingAgainstBaseURL: false)
+                    returnURLComponents?.host = "appBackupResponse"
+                    guard let returnURL = returnURLComponents?.url else { throw OperationError.openAppFailed(name: appName) }
+                    
+                    var openURLComponents = URLComponents()
+                    openURLComponents.scheme = installedApp.openAppURL.scheme
+                    openURLComponents.host = self.action.rawValue
+                    openURLComponents.queryItems = [URLQueryItem(name: "returnURL", value: returnURL.absoluteString)]
+                    
+                    guard let openURL = openURLComponents.url else { throw OperationError.openAppFailed(name: appName) }
+                    
+                    DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
+                        let currentTime = CFAbsoluteTimeGetCurrent()
+                        
+                        UIApplication.shared.open(openURL, options: [:]) { (success) in
+                            let elapsedTime = CFAbsoluteTimeGetCurrent() - currentTime
+                            
+                            if success
+                            {
+                                self.registerObservers()
+                            }
+                            else if elapsedTime < 0.5
+                            {
+                                // Failed too quickly for human to respond to alert, possibly still finalizing installation.
+                                // Try again in a couple seconds.
+                                
+                                print("Failed too quickly, retrying after a few seconds...")
+                                
+                                DispatchQueue.main.asyncAfter(deadline: .now() + 2.0) {
+                                    UIApplication.shared.open(openURL, options: [:]) { (success) in
+                                        if success
+                                        {
+                                            self.registerObservers()
+                                        }
+                                        else
+                                        {
+                                            self.finish(.failure(OperationError.openAppFailed(name: appName)))
+                                        }
+                                    }
+                                }
+                            }
+                            else
+                            {
+                                self.finish(.failure(OperationError.openAppFailed(name: appName)))
+                            }
+                        }
+                    }
+                }
+                catch
+                {
+                    self.finish(.failure(error))
+                }
+            }
+        }
+        catch
+        {
+            self.finish(.failure(error))
+        }
+    }
+    
+    override func finish(_ result: Result<Void, Error>)
+    {
+        let result = result.mapError { (error) -> Error in
+            let appName = self.appName ?? self.context.bundleIdentifier
+            
+            switch (error, self.action)
+            {
+            case (let error as NSError, _) where (self.context.error as NSError?) == error: fallthrough
+            case (OperationError.cancelled, _):
+                return error
+                
+            case (let error as NSError, .backup):
+                let localizedFailure = String(format: NSLocalizedString("Could not back up “%@”.", comment: ""), appName)
+                return error.withLocalizedFailure(localizedFailure)
+                
+            case (let error as NSError, .restore):
+                let localizedFailure = String(format: NSLocalizedString("Could not restore “%@”.", comment: ""), appName)
+                return error.withLocalizedFailure(localizedFailure)
+            }
+        }
+        
+        switch result
+        {
+        case .success: self.progress.completedUnitCount += 1
+        case .failure: break
+        }
+        
+        super.finish(result)
+    }
+}
+
+private extension BackupAppOperation
+{
+    func registerObservers()
+    {
+        var applicationWillReturnObserver: NSObjectProtocol!
+        applicationWillReturnObserver = NotificationCenter.default.addObserver(forName: UIApplication.willEnterForegroundNotification, object: nil, queue: .main) { [weak self] (notification) in
+            guard let self = self, !self.isFinished else { return }
+            
+            self.timeoutTimer = Timer.scheduledTimer(withTimeInterval: 5, repeats: false) { [weak self] (timer) in
+                // Final delay to ensure we don't prematurely return failure
+                // in case timer expired while we were in background, but
+                // are now returning to app with success response.
+                DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
+                    guard let self = self, !self.isFinished else { return }
+                    self.finish(.failure(OperationError.timedOut))
+                }
+            }
+            
+            NotificationCenter.default.removeObserver(applicationWillReturnObserver!)
+        }
+        
+        var backupResponseObserver: NSObjectProtocol!
+        backupResponseObserver = NotificationCenter.default.addObserver(forName: AppDelegate.appBackupDidFinish, object: nil, queue: nil) { [weak self] (notification) in
+            self?.timeoutTimer?.invalidate()
+            
+            let result = notification.userInfo?[AppDelegate.appBackupResultKey] as? Result<Void, Error> ?? .failure(OperationError.unknownResult)
+            self?.finish(result)
+            
+            NotificationCenter.default.removeObserver(backupResponseObserver!)
+        }
+    }
+}

AltStore/Operations/OperationContexts.swift

@@ -105,6 +105,12 @@ class InstallAppOperationContext: AppOperationContext
     
     var resignedApp: ALTApplication?
     var installationConnection: ServerConnection?
+    var installedApp: InstalledApp? {
+        didSet {
+            self.installedAppContext = self.installedApp?.managedObjectContext
+        }
+    }
+    private var installedAppContext: NSManagedObjectContext?
     
     var beginInstallationHandler: ((InstalledApp) -> Void)?
 }

AltStore/Operations/OperationError.swift

@@ -14,6 +14,7 @@ enum OperationError: LocalizedError
     case unknown
     case unknownResult
     case cancelled
+    case timedOut
     
     case notAuthenticated
     case appNotFound
@@ -28,17 +29,23 @@ enum OperationError: LocalizedError
     
     case noSources
     
+    case openAppFailed(name: String)
+    case missingAppGroup
+    
     var failureReason: String? {
         switch self {
         case .unknown: return NSLocalizedString("An unknown error occured.", comment: "")
         case .unknownResult: return NSLocalizedString("The operation returned an unknown result.", comment: "")
         case .cancelled: return NSLocalizedString("The operation was cancelled.", comment: "")
+        case .timedOut: return NSLocalizedString("The operation timed out.", comment: "")
         case .notAuthenticated: return NSLocalizedString("You are not signed in.", comment: "")
         case .appNotFound: return NSLocalizedString("App not found.", comment: "")
         case .unknownUDID: return NSLocalizedString("Unknown device UDID.", comment: "")
         case .invalidApp: return NSLocalizedString("The app is invalid.", comment: "")
         case .invalidParameters: return NSLocalizedString("Invalid parameters.", comment: "")
         case .noSources: return NSLocalizedString("There are no AltStore sources.", comment: "")
+        case .openAppFailed(let name): return String(format: NSLocalizedString("AltStore was denied permission to launch %@.", comment: ""), name)
+        case .missingAppGroup: return NSLocalizedString("AltStore's shared app group could not be found.", comment: "")
         case .iOSVersionNotSupported(let app):
             let name = app.name