Add ability to import SSH keys from the Files app

pass/Controllers/GitRepositorySettingsTableViewController.swift

@@ -247,6 +247,9 @@ class GitRepositorySettingsTableViewController: UITableViewController {
         optionMenu.addAction(UIAlertAction(title: SSHKeyArmorImportTableViewController.menuLabel, style: .default) { _ in
             self.performSegue(withIdentifier: "setGitSSHKeyByArmorSegue", sender: self)
         })
+        optionMenu.addAction(UIAlertAction(title: SSHKeyFileImportTableViewController.menuLabel, style: .default) { _ in
+            self.performSegue(withIdentifier: "setGitSSHKeyByFileSegue", sender: self)
+        })
 
         if isReadyToUse() {
             optionMenu.addAction(UIAlertAction(title: "\(Self.menuLabel) (\("Import".localize()))", style: .default) { _ in

pass/Controllers/SSHKeyFileImportTableViewController.swift

@@ -0,0 +1,72 @@
+//
+//  SSHKeyFileImportTableViewController.swift
+//  pass
+//
+//  Created by Danny Moesch on 15.02.20.
+//  Copyright © 2020 Bob Sun. All rights reserved.
+//
+
+import passKit
+import SVProgressHUD
+
+class SSHKeyFileImportTableViewController: AutoCellHeightUITableViewController {
+
+    @IBOutlet weak var sshPrivateKeyFile: UITableViewCell!
+
+    private var privateKey: String? = nil
+
+    @IBAction func doneButtonTapped(_ sender: Any) {
+        performSegue(withIdentifier: "importSSHKeySegue", sender: self)
+    }
+
+    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
+        let cell = tableView.cellForRow(at: indexPath)
+        let picker = UIDocumentPickerViewController(documentTypes: ["public.data"], in: .open)
+        cell?.isSelected = false
+        guard cell == sshPrivateKeyFile else {
+            return
+        }
+        picker.delegate = self
+        if #available(iOS 13.0, *) {
+            picker.shouldShowFileExtensions = true
+        }
+        present(picker, animated: true, completion: nil)
+    }
+}
+
+extension SSHKeyFileImportTableViewController: UIDocumentPickerDelegate {
+
+    func documentPicker(_: UIDocumentPickerViewController, didPickDocumentsAt url: [URL]) {
+        guard let url = url.first else {
+            return
+        }
+        let fileName = url.lastPathComponent
+        do {
+            privateKey = try String(contentsOf: url, encoding: .ascii)
+            sshPrivateKeyFile.textLabel?.text = fileName
+        } catch {
+            Utils.alert(title: "CannotImportFile".localize(), message: "FileCannotBeImported.".localize(fileName), controller: self)
+        }
+    }
+}
+
+extension SSHKeyFileImportTableViewController: KeyImporter {
+
+    static let keySource = KeySource.file
+    static let label = "LoadFromFiles".localize()
+
+    func isReadyToUse() -> Bool {
+        guard privateKey != nil else {
+            Utils.alert(title: "CannotSave".localize(), message: "SetPrivateKeyUrl.".localize(), controller: self)
+            return false
+        }
+        return true
+    }
+
+    func importKeys() throws {
+        guard let privateKey = privateKey else {
+            return
+        }
+        try KeyFileManager.PrivateSsh.importKey(from: privateKey)
+    }
+}