From 66bfe45f993581d49d738899a760a133c9a15958 Mon Sep 17 00:00:00 2001
From: Kevin Chyn <kchyn@google.com>
Date: Thu, 30 Jul 2020 14:04:20 -0700
Subject: [PATCH] BiometricEnrollIntro should use non-blocking
 generateChallenge

GenerateChallenge used to block when showing the credential screen.
Now that GenerateChallenge is moved to after the credential screen
is shown, we need to delay the next button instead. This is generally
non percievable to the user, but this is more robust against busy
system server.

Fixes: 161325267
Test: Enroll fingerprint/face device
Change-Id: I0fbbef8bf469e32bed251acf22556ad2ea8e2933
---
 .../BiometricEnrollIntroduction.java          | 21 ++++++++++++++-----
 .../face/FaceEnrollIntroduction.java          |  7 ++++---
 .../FingerprintEnrollIntroduction.java        |  7 ++++---
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/com/android/settings/biometrics/BiometricEnrollIntroduction.java b/src/com/android/settings/biometrics/BiometricEnrollIntroduction.java
index c97c4d98b7b..db2f2913342 100644
--- a/src/com/android/settings/biometrics/BiometricEnrollIntroduction.java
+++ b/src/com/android/settings/biometrics/BiometricEnrollIntroduction.java
@@ -101,7 +101,7 @@ public abstract class BiometricEnrollIntroduction extends BiometricEnrollBase
     /**
      * @return the challenge generated by the biometric hardware
      */
-    protected abstract long getChallenge();
+    protected abstract void getChallenge(GenerateChallengeCallback callback);
 
     /**
      * @return one of the ChooseLockSettingsHelper#EXTRA_KEY_FOR_* constants
@@ -125,6 +125,10 @@ public abstract class BiometricEnrollIntroduction extends BiometricEnrollBase
      */
     public abstract void onClick(LinkSpan span);
 
+    protected interface GenerateChallengeCallback {
+        void onChallengeGenerated(long challenge);
+    }
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -267,12 +271,15 @@ public abstract class BiometricEnrollIntroduction extends BiometricEnrollBase
                 return;
             }
         } else if (requestCode == CHOOSE_LOCK_GENERIC_REQUEST) {
+            mConfirmingCredentials = false;
             if (resultCode == RESULT_FINISHED) {
                 updatePasswordQuality();
-                mToken = BiometricUtils.requestGatekeeperHat(this, data, mUserId, getChallenge());
                 overridePendingTransition(R.anim.sud_slide_next_in, R.anim.sud_slide_next_out);
-                mConfirmingCredentials = false;
-                return;
+                getNextButton().setEnabled(false);
+                getChallenge((challenge -> {
+                    mToken = BiometricUtils.requestGatekeeperHat(this, data, mUserId, challenge);
+                    getNextButton().setEnabled(true);
+                }));
             } else {
                 setResult(resultCode, data);
                 finish();
@@ -280,8 +287,12 @@ public abstract class BiometricEnrollIntroduction extends BiometricEnrollBase
         } else if (requestCode == CONFIRM_REQUEST) {
             mConfirmingCredentials = false;
             if (resultCode == RESULT_OK && data != null) {
-                mToken = BiometricUtils.requestGatekeeperHat(this, data, mUserId, getChallenge());
                 overridePendingTransition(R.anim.sud_slide_next_in, R.anim.sud_slide_next_out);
+                getNextButton().setEnabled(false);
+                getChallenge((challenge -> {
+                    mToken = BiometricUtils.requestGatekeeperHat(this, data, mUserId, challenge);
+                    getNextButton().setEnabled(true);
+                }));
             } else {
                 setResult(resultCode, data);
                 finish();
diff --git a/src/com/android/settings/biometrics/face/FaceEnrollIntroduction.java b/src/com/android/settings/biometrics/face/FaceEnrollIntroduction.java
index dbdf03de3bb..378a3c12f5d 100644
--- a/src/com/android/settings/biometrics/face/FaceEnrollIntroduction.java
+++ b/src/com/android/settings/biometrics/face/FaceEnrollIntroduction.java
@@ -180,12 +180,13 @@ public class FaceEnrollIntroduction extends BiometricEnrollIntroduction {
     }
 
     @Override
-    protected long getChallenge() {
+    protected void getChallenge(GenerateChallengeCallback callback) {
         mFaceManager = Utils.getFaceManagerOrNull(this);
         if (mFaceManager == null) {
-            return 0;
+            callback.onChallengeGenerated(0L);
+            return;
         }
-        return mFaceManager.generateChallengeBlocking();
+        mFaceManager.generateChallenge(callback::onChallengeGenerated);
     }
 
     @Override
diff --git a/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollIntroduction.java b/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollIntroduction.java
index ccfb0f26155..0b5c7b0ff77 100644
--- a/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollIntroduction.java
+++ b/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollIntroduction.java
@@ -131,12 +131,13 @@ public class FingerprintEnrollIntroduction extends BiometricEnrollIntroduction {
     }
 
     @Override
-    protected long getChallenge() {
+    protected void getChallenge(GenerateChallengeCallback callback) {
         mFingerprintManager = Utils.getFingerprintManagerOrNull(this);
         if (mFingerprintManager == null) {
-            return 0;
+            callback.onChallengeGenerated(0L);
+            return;
         }
-        return mFingerprintManager.generateChallengeBlocking();
+        mFingerprintManager.generateChallenge(callback::onChallengeGenerated);
     }
 
     @Override