WireGuard add extra source files

Signed-off-by: Joseph Mattello <mail@joemattiello.com>

WireguardNetworkExtension/ErrorNotifier.swift

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2021 WireGuard LLC. All Rights Reserved.
+
+import NetworkExtension
+
+class ErrorNotifier {
+    let activationAttemptId: String?
+
+    init(activationAttemptId: String?) {
+        self.activationAttemptId = activationAttemptId
+        ErrorNotifier.removeLastErrorFile()
+    }
+
+    func notify(_ error: PacketTunnelProviderError) {
+        guard let activationAttemptId = activationAttemptId, let lastErrorFilePath = FileManager.networkExtensionLastErrorFileURL?.path else { return }
+        let errorMessageData = "\(activationAttemptId)\n\(error)".data(using: .utf8)
+        FileManager.default.createFile(atPath: lastErrorFilePath, contents: errorMessageData, attributes: nil)
+    }
+
+    static func removeLastErrorFile() {
+        if let lastErrorFileURL = FileManager.networkExtensionLastErrorFileURL {
+            _ = FileManager.deleteFile(at: lastErrorFileURL)
+        }
+    }
+}