[AltServer] Improves error messages

Shared/Categories/NSError+ALTServerError.m

@@ -75,7 +75,7 @@ NSErrorUserInfoKey const ALTDeviceNameErrorKey = @"deviceName";
             
         case ALTServerErrorConnectionFailed:
 #if TARGET_OS_OSX
-            return NSLocalizedString(@"Could not connect to device.", @"");
+            return NSLocalizedString(@"There was an error connecting to the device.", @"");
 #else
             return NSLocalizedString(@"Could not connect to AltServer.", @"");
 #endif
@@ -114,10 +114,10 @@ NSErrorUserInfoKey const ALTDeviceNameErrorKey = @"deviceName";
             return NSLocalizedString(@"Received an unknown response from AltServer.", @"");
             
         case ALTServerErrorInvalidAnisetteData:
-            return NSLocalizedString(@"Invalid anisette data.", @"");
+            return NSLocalizedString(@"The provided anisette data is invalid.", @"");
             
         case ALTServerErrorPluginNotFound:
-            return NSLocalizedString(@"Could not connect to Mail plug-in.", @"");
+            return NSLocalizedString(@"AltServer could not connect to Mail plug-in.", @"");
             
         case ALTServerErrorProfileNotFound:
             return [self profileErrorLocalizedDescriptionWithBaseDescription:NSLocalizedString(@"Could not find profile", "")];

Shared/Extensions/NSError+AltStore.swift

@@ -0,0 +1,122 @@
+//
+//  NSError+AltStore.swift
+//  AltStore
+//
+//  Created by Riley Testut on 3/11/20.
+//  Copyright © 2020 Riley Testut. All rights reserved.
+//
+
+import Foundation
+
+extension NSError
+{
+    @objc(alt_localizedFailure)
+    var localizedFailure: String? {
+        let localizedFailure = (self.userInfo[NSLocalizedFailureErrorKey] as? String) ?? (NSError.userInfoValueProvider(forDomain: self.domain)?(self, NSLocalizedFailureErrorKey) as? String)
+        return localizedFailure
+    }
+    
+    @objc(alt_errorWithLocalizedFailure:)
+    func withLocalizedFailure(_ failure: String) -> NSError
+    {
+        var userInfo = self.userInfo
+        userInfo[NSLocalizedFailureErrorKey] = failure
+        
+        if let failureReason = self.localizedFailureReason
+        {
+            userInfo[NSLocalizedFailureReasonErrorKey] = failureReason
+        }
+        else if self.localizedFailure == nil && self.localizedFailureReason == nil && self.localizedDescription.contains(self.localizedErrorCode)
+        {
+            // Default localizedDescription, so replace with just the localized error code portion.
+            userInfo[NSLocalizedFailureReasonErrorKey] = "(\(self.localizedErrorCode).)"
+        }
+        else
+        {
+            userInfo[NSLocalizedFailureReasonErrorKey] = self.localizedDescription
+        }
+        
+        if let localizedDescription = NSError.userInfoValueProvider(forDomain: self.domain)?(self, NSLocalizedDescriptionKey) as? String
+        {
+            userInfo[NSLocalizedDescriptionKey] = localizedDescription
+        }
+        
+        // Don't accidentally remove localizedDescription from dictionary
+        // userInfo[NSLocalizedDescriptionKey] = NSError.userInfoValueProvider(forDomain: self.domain)?(self, NSLocalizedDescriptionKey) as? String
+        
+        if let recoverySuggestion = self.localizedRecoverySuggestion
+        {
+            userInfo[NSLocalizedRecoverySuggestionErrorKey] = recoverySuggestion
+        }
+        
+        let error = NSError(domain: self.domain, code: self.code, userInfo: userInfo)
+        return error
+    }
+    
+    func sanitizedForCoreData() -> NSError
+    {
+        var userInfo = self.userInfo
+        userInfo[NSLocalizedFailureErrorKey] = self.localizedFailure
+        userInfo[NSLocalizedDescriptionKey] = self.localizedDescription
+        userInfo[NSLocalizedFailureReasonErrorKey] = self.localizedFailureReason
+        userInfo[NSLocalizedRecoverySuggestionErrorKey] = self.localizedRecoverySuggestion
+        
+        // Remove non-ObjC-compliant userInfo values.
+        userInfo["NSCodingPath"] = nil
+        
+        let error = NSError(domain: self.domain, code: self.code, userInfo: userInfo)
+        return error
+    }
+}
+
+extension Error
+{
+    var underlyingError: Error? {
+        let underlyingError = (self as NSError).userInfo[NSUnderlyingErrorKey] as? Error
+        return underlyingError
+    }
+    
+    var localizedErrorCode: String {
+        let localizedErrorCode = String(format: NSLocalizedString("%@ error %@", comment: ""), (self as NSError).domain, (self as NSError).code as NSNumber)
+        return localizedErrorCode
+    }
+}
+
+protocol ALTLocalizedError: LocalizedError, CustomNSError
+{
+    var failure: String? { get }
+    
+    var underlyingError: Error? { get }
+}
+
+extension ALTLocalizedError
+{
+    var errorUserInfo: [String : Any] {
+        let userInfo = ([
+            NSLocalizedDescriptionKey: self.errorDescription,
+            NSLocalizedFailureReasonErrorKey: self.failureReason,
+            NSLocalizedFailureErrorKey: self.failure,
+            NSUnderlyingErrorKey: self.underlyingError
+        ] as [String: Any?]).compactMapValues { $0 }
+        return userInfo
+    }
+    
+    var underlyingError: Error? {
+        // Error's default implementation calls errorUserInfo,
+        // but ALTLocalizedError.errorUserInfo calls underlyingError.
+        // Return nil to prevent infinite recursion.
+        return nil
+    }
+    
+    var errorDescription: String? {
+        guard let errorFailure = self.failure else { return (self.underlyingError as NSError?)?.localizedDescription }
+        guard let failureReason = self.failureReason else { return errorFailure }
+        
+        let errorDescription = errorFailure + " " + failureReason
+        return errorDescription
+    }
+    
+    var failureReason: String? { (self.underlyingError as NSError?)?.localizedDescription }
+    var recoverySuggestion: String? { (self.underlyingError as NSError?)?.localizedRecoverySuggestion }
+    var helpAnchor: String? { (self.underlyingError as NSError?)?.helpAnchor }
+}