refactor PushUtils

Signed-off-by: Marcel Hibbe <dev@mhibbe.de>

app/src/main/java/com/nextcloud/talk/utils/PushUtils.java

@@ -85,21 +85,17 @@ public class PushUtils {
     @Inject
     NcApi ncApi;
 
-    private File keysFile;
-    private File publicKeyFile;
-    private File privateKeyFile;
+    private final File publicKeyFile;
+    private final File privateKeyFile;
 
-    private String proxyServer;
+    private final String proxyServer;
 
     public PushUtils() {
         NextcloudTalkApplication.Companion.getSharedApplication().getComponentApplication().inject(this);
 
-        keysFile = NextcloudTalkApplication.Companion.getSharedApplication().getDir("PushKeyStore", Context.MODE_PRIVATE);
-
-        publicKeyFile = new File(NextcloudTalkApplication.Companion.getSharedApplication().getDir("PushKeystore",
-                                                                                                  Context.MODE_PRIVATE), "push_key.pub");
-        privateKeyFile = new File(NextcloudTalkApplication.Companion.getSharedApplication().getDir("PushKeystore",
-                                                                                                   Context.MODE_PRIVATE), "push_key.priv");
+        String keyPath = NextcloudTalkApplication.Companion.getSharedApplication().getDir("PushKeystore", Context.MODE_PRIVATE).getAbsolutePath();
+        publicKeyFile = new File(keyPath, "push_key.pub");
+        privateKeyFile = new File(keyPath, "push_key.priv");
         proxyServer = NextcloudTalkApplication.Companion.getSharedApplication().getResources().
             getString(R.string.nc_push_server_url);
     }
@@ -190,9 +186,6 @@ public class PushUtils {
 
     public int generateRsa2048KeyPair() {
         if (!publicKeyFile.exists() && !privateKeyFile.exists()) {
-            if (!keysFile.exists()) {
-                keysFile.mkdirs();
-            }
 
             KeyPairGenerator keyGen = null;
             try {
@@ -226,7 +219,6 @@ public class PushUtils {
         String token = appPreferences.getPushToken();
 
         if (!TextUtils.isEmpty(token)) {
-            String credentials;
             String pushTokenHash = generateSHA512Hash(token).toLowerCase();
             PublicKey devicePublicKey = (PublicKey) readKeyFromFile(true);
             if (devicePublicKey != null) {