From c923c2286e24df8bc4d5fec9f28d6ed6043a072c Mon Sep 17 00:00:00 2001
From: Jing Ji <jji@google.com>
Date: Fri, 22 Jan 2021 18:15:37 -0800
Subject: [PATCH] Cache the owner name string in UserManagerService

It's read frequently but it won't be changed until a configuration
change. So cache the string.

Bug: 178235824
Bug: 162450085
Test: Manual - switch languages and check 'dumpsys user |grep Owner'
Test: atest UserManagerServiceUserInfoTest
Test: atest UserManagerServiceUserTypeTest
Test: atest UserManagerTest
Change-Id: I337f403e38e9d54f545e773309d8bd1651cbcdf0
---
 .../android/server/pm/UserManagerService.java | 39 ++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/services/core/java/com/android/server/pm/UserManagerService.java b/services/core/java/com/android/server/pm/UserManagerService.java
index 314510b89cb91..f43240bd810a9 100644
--- a/services/core/java/com/android/server/pm/UserManagerService.java
+++ b/services/core/java/com/android/server/pm/UserManagerService.java
@@ -47,6 +47,7 @@ import android.content.pm.PackageManagerInternal;
 import android.content.pm.ShortcutServiceInternal;
 import android.content.pm.UserInfo;
 import android.content.pm.UserInfo.UserInfoFlag;
+import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.os.Binder;
@@ -92,6 +93,7 @@ import android.util.SparseArray;
 import android.util.SparseBooleanArray;
 import android.util.SparseIntArray;
 import android.util.TimeUtils;
+import android.util.TypedValue;
 import android.util.TypedXmlPullParser;
 import android.util.TypedXmlSerializer;
 import android.util.Xml;
@@ -139,6 +141,7 @@ import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * Service for {@link UserManager}.
@@ -461,6 +464,26 @@ public class UserManagerService extends IUserManager.Stub {
         }
     };
 
+    /**
+     * Cache the owner name string, since it could be read repeatedly on a critical code path
+     * but hit by slow IO. This could be eliminated once we have the cached UserInfo in place.
+     */
+    private final AtomicReference<String> mOwnerName = new AtomicReference<>();
+
+    private final TypedValue mOwnerNameTypedValue = new TypedValue();
+
+    private final Configuration mLastConfiguration = new Configuration();
+
+    private final BroadcastReceiver mConfigurationChangeReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            if (!Intent.ACTION_CONFIGURATION_CHANGED.equals(intent.getAction())) {
+                return;
+            }
+            invalidateOwnerNameIfNecessary(context.getResources(), false /* forceUpdate */);
+        }
+    };
+
     // TODO(b/161915546): remove once userWithName() is fixed / removed
     // Use to debug / dump when user 0 is allocated at userWithName()
     public static final boolean DBG_ALLOCATION = false; // DO NOT SUBMIT WITH TRUE
@@ -636,6 +659,7 @@ public class UserManagerService extends IUserManager.Stub {
         mHandler = new MainHandler();
         mUserDataPreparer = userDataPreparer;
         mUserTypes = UserTypeFactory.getUserTypes();
+        invalidateOwnerNameIfNecessary(context.getResources(), true /* forceUpdate */);
         synchronized (mPackagesLock) {
             mUsersDir = new File(dataDir, USER_INFO_DIR);
             mUsersDir.mkdirs();
@@ -669,6 +693,10 @@ public class UserManagerService extends IUserManager.Stub {
         mContext.registerReceiver(mDisableQuietModeCallback,
                 new IntentFilter(ACTION_DISABLE_QUIET_MODE_AFTER_UNLOCK),
                 null, mHandler);
+
+        mContext.registerReceiver(mConfigurationChangeReceiver,
+                new IntentFilter(Intent.ACTION_CONFIGURATION_CHANGED),
+                null, mHandler);
     }
 
     /**
@@ -2851,7 +2879,16 @@ public class UserManagerService extends IUserManager.Stub {
     }
 
     private String getOwnerName() {
-        return mContext.getResources().getString(com.android.internal.R.string.owner_name);
+        return mOwnerName.get();
+    }
+
+    private void invalidateOwnerNameIfNecessary(@NonNull Resources res, boolean forceUpdate) {
+        final int configChanges = mLastConfiguration.updateFrom(res.getConfiguration());
+        if (forceUpdate || (configChanges & mOwnerNameTypedValue.changingConfigurations) != 0) {
+            res.getValue(com.android.internal.R.string.owner_name, mOwnerNameTypedValue, true);
+            final CharSequence ownerName = mOwnerNameTypedValue.coerceToString();
+            mOwnerName.set(ownerName != null ? ownerName.toString() : null);
+        }
     }
 
     private void scheduleWriteUser(UserData userData) {