[4/n] FRR data cleanup

Add logic to delete data when removing a user.

Bug: 258872351
Test: AuthenticationStatsPersisterTest
Change-Id: I5f89ffbeeb0f01fbaffe22e7a372d05a6e22093d

services/core/java/com/android/server/biometrics/AuthenticationStatsCollector.java

@@ -18,10 +18,14 @@ package com.android.server.biometrics;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.content.BroadcastReceiver;
 import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
 import android.content.pm.PackageManager;
 import android.hardware.face.FaceManager;
 import android.hardware.fingerprint.FingerprintManager;
+import android.os.UserHandle;
 
 import com.android.internal.R;
 import com.android.internal.annotations.VisibleForTesting;
@@ -56,6 +60,17 @@ public class AuthenticationStatsCollector {
     @NonNull private AuthenticationStatsPersister mAuthenticationStatsPersister;
     @NonNull private BiometricNotification mBiometricNotification;
 
+    private final BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(@NonNull Context context, @NonNull Intent intent) {
+            final int userId = intent.getIntExtra(Intent.EXTRA_USER_HANDLE, UserHandle.USER_NULL);
+            if (userId != UserHandle.USER_NULL
+                    && intent.getAction().equals(Intent.ACTION_USER_REMOVED)) {
+                onUserRemoved(userId);
+            }
+        }
+    };
+
     public AuthenticationStatsCollector(@NonNull Context context, int modality,
             @NonNull BiometricNotification biometricNotification) {
         mContext = context;
@@ -64,6 +79,8 @@ public class AuthenticationStatsCollector {
         mUserAuthenticationStatsMap = new HashMap<>();
         mModality = modality;
         mBiometricNotification = biometricNotification;
+
+        context.registerReceiver(mBroadcastReceiver, new IntentFilter(Intent.ACTION_USER_REMOVED));
     }
 
     private void initializeUserAuthenticationStatsMap() {
@@ -146,6 +163,11 @@ public class AuthenticationStatsCollector {
         }
     }
 
+    private void onUserRemoved(final int userId) {
+        mUserAuthenticationStatsMap.remove(userId);
+        mAuthenticationStatsPersister.removeFrrStats(userId);
+    }
+
     /**
      * Only being used in tests. Callers should not make any changes to the returned
      * authentication stats.

services/core/java/com/android/server/biometrics/AuthenticationStatsPersister.java

@@ -93,6 +93,29 @@ public class AuthenticationStatsPersister {
         return authenticationStatsList;
     }
 
+    /**
+     * Remove frr data for a specific user.
+     */
+    public void removeFrrStats(int userId) {
+        try {
+            // Copy into a new HashSet to avoid iterator exception.
+            Set<String> frrStatsSet = new HashSet<>(readFrrStats());
+
+            // Remove the old authentication stat for the user if it exists.
+            for (Iterator<String> iterator = frrStatsSet.iterator(); iterator.hasNext();) {
+                String frrStats = iterator.next();
+                JSONObject frrStatJson = new JSONObject(frrStats);
+                if (getValue(frrStatJson, USER_ID).equals(String.valueOf(userId))) {
+                    iterator.remove();
+                    break;
+                }
+            }
+
+            mSharedPreferences.edit().putStringSet(KEY, frrStatsSet).apply();
+        } catch (JSONException ignored) {
+        }
+    }
+
     /**
      * Persist frr data for a specific user.
      */

services/tests/servicestests/src/com/android/server/biometrics/AuthenticationStatsPersisterTest.java

@@ -211,6 +211,20 @@ public class AuthenticationStatsPersisterTest {
         assertThat(mStringSetArgumentCaptor.getValue()).contains(expectedFrrStats);
     }
 
+    @Test
+    public void removeFrrStats_existingUser_shouldUpdateRecord() throws JSONException {
+        AuthenticationStats authenticationStats = new AuthenticationStats(USER_ID_1,
+                300 /* totalAttempts */, 10 /* rejectedAttempts */,
+                0 /* enrollmentNotifications */, BiometricsProtoEnums.MODALITY_FACE);
+        when(mSharedPreferences.getStringSet(eq(KEY), anySet())).thenReturn(
+                Set.of(buildFrrStats(authenticationStats)));
+
+        mAuthenticationStatsPersister.removeFrrStats(USER_ID_1);
+
+        verify(mEditor).putStringSet(eq(KEY), mStringSetArgumentCaptor.capture());
+        assertThat(mStringSetArgumentCaptor.getValue()).doesNotContain(authenticationStats);
+    }
+
     private String buildFrrStats(AuthenticationStats authenticationStats)
             throws JSONException {
         if (authenticationStats.getModality() == BiometricsProtoEnums.MODALITY_FACE) {