auth: timeout refresh token to avoid ANR in authenticator

Author: zerox80

.gitignore

@@ -33,3 +33,4 @@ lint-*ml
 
 # Prevent exidental commits of build folders
 opencloudApp/release
+settings.local.json

opencloudApp/src/main/java/eu/opencloud/android/presentation/authentication/AccountAuthenticator.java

@@ -49,6 +49,11 @@
 import timber.log.Timber;
 
 import java.io.File;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
 import static eu.opencloud.android.data.authentication.AuthenticationConstantsKt.KEY_CLIENT_REGISTRATION_CLIENT_EXPIRATION_DATE;
 import static eu.opencloud.android.data.authentication.AuthenticationConstantsKt.KEY_CLIENT_REGISTRATION_CLIENT_ID;
@@ -318,6 +323,30 @@ private String refreshToken(
             String authTokenType,
             AccountManager accountManager
     ) {
+        // Run refresh on a worker with a short timeout to avoid ANR in AccountAuthenticatorService.
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+        Future<String> future = executor.submit(() ->
+                refreshTokenInternal(account, authTokenType, accountManager)
+        );
+        try {
+            return future.get(10, TimeUnit.SECONDS); // stay below 20s ANR window
+        } catch (TimeoutException e) {
+            Timber.w(e, "OAuth token refresh timed out, fallback to interactive login");
+            future.cancel(true);
+            return null;
+        } catch (Exception e) {
+            Timber.e(e, "OAuth token refresh failed");
+            return null;
+        } finally {
+            executor.shutdownNow();
+        }
+    }
+
+    private String refreshTokenInternal(
+            Account account,
+            String authTokenType,
+            AccountManager accountManager
+    ) {
 
         // Prepare everything to perform the token request
         String refreshToken = accountManager.getUserData(account, KEY_OAUTH2_REFRESH_TOKEN);