Implement custom error messages for Coding errors

1 files changed, 53 insertions, 0 deletions

diff --git a/ios/MullvadVPN/CodingErrors+ChainedError.swift b/ios/MullvadVPN/CodingErrors+ChainedError.swift
new file mode 100644
index 0000000000..e14d61473b
--- /dev/null
+++ b/ios/MullvadVPN/CodingErrors+ChainedError.swift
@@ -0,0 +1,53 @@
+//
+//  CodingErrors+ChainedError.swift
+//  MullvadVPN
+//
+//  Created by pronebird on 17/02/2022.
+//  Copyright © 2022 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+
+extension DecodingError: CustomChainedErrorDescriptionProtocol {
+    var customErrorDescription: String? {
+        switch self {
+        case .typeMismatch(let type, let context):
+            return "Type mismatch, expected \(type) for key at \"\(context.codingPath.codingPathString)\"."
+
+        case .valueNotFound(_, let context):
+            return "Value not found at \"\(context.codingPath.codingPathString)\"."
+
+        case .keyNotFound(let codingKey, let context):
+            return "Key \"\(codingKey.stringValue)\" not found at \"\(context.codingPath.codingPathString)\"."
+
+        case .dataCorrupted:
+            return "Data corrupted."
+
+        @unknown default:
+            return nil
+        }
+    }
+}
+
+extension EncodingError: CustomChainedErrorDescriptionProtocol {
+    var customErrorDescription: String? {
+        switch self {
+        case .invalidValue(_, let context):
+            return "Invalid value at \"\(context.codingPath.codingPathString)\""
+
+        @unknown default:
+            return nil
+        }
+    }
+}
+
+private extension Array where Element == CodingKey {
+    var codingPathString: String {
+        if isEmpty {
+            return "<root>"
+        } else {
+            return map { $0.stringValue }
+                .joined(separator: ".")
+        }
+    }
+}