From 5745b057ecae6137afe46b44f40315bd3d65b27d Mon Sep 17 00:00:00 2001
From: Julius D'souza <jdsouza@google.com>
Date: Tue, 18 Feb 2020 11:27:25 -0800
Subject: [PATCH] Add background thread notes for package restriction
 serialisation.

Serialising package restrictions uses synchronous disk access; callers
of these methods should probably use background threads for this.

Bug: 149216360
Test: TreeHugger
Change-Id: I6607a7225bf7daaad8a78e4d1e4c585ba5ac3efc
Signed-off-by: Julius D'souza <jdsouza@google.com>
---
 core/java/android/content/pm/PackageManager.java             | 3 ++-
 .../core/java/android/content/pm/PackageManagerInternal.java | 2 ++
 .../java/com/android/server/pm/PackageManagerService.java    | 5 ++++-
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/core/java/android/content/pm/PackageManager.java b/core/java/android/content/pm/PackageManager.java
index ab3982a460d83..e09632ca8869f 100644
--- a/core/java/android/content/pm/PackageManager.java
+++ b/core/java/android/content/pm/PackageManager.java
@@ -979,7 +979,8 @@ public abstract class PackageManager {
      * Flag parameter for
      * {@link #setComponentEnabledSetting(android.content.ComponentName, int, int)} to indicate
      * that the given user's package restrictions state will be serialised to disk after the
-     * component state has been updated.
+     * component state has been updated. Note that this is synchronous disk access, so calls using
+     * this flag should be run on a background thread.
      */
     public static final int SYNCHRONOUS = 0x00000002;
 
diff --git a/services/core/java/android/content/pm/PackageManagerInternal.java b/services/core/java/android/content/pm/PackageManagerInternal.java
index 8b2bfa10a0299..1230bd79ff976 100644
--- a/services/core/java/android/content/pm/PackageManagerInternal.java
+++ b/services/core/java/android/content/pm/PackageManagerInternal.java
@@ -21,6 +21,7 @@ import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.UserIdInt;
+import android.annotation.WorkerThread;
 import android.content.ComponentName;
 import android.content.ContentResolver;
 import android.content.Intent;
@@ -261,6 +262,7 @@ public abstract class PackageManagerInternal {
     /**
      * Flushes package restrictions for the given user immediately to disk.
      */
+    @WorkerThread
     public abstract void flushPackageRestrictions(int userId);
 
     /**
diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index 52052f8dd8711..967b25243f45b 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -130,6 +130,7 @@ import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.UserIdInt;
+import android.annotation.WorkerThread;
 import android.app.ActivityManager;
 import android.app.AppOpsManager;
 import android.app.ApplicationPackageManager;
@@ -213,7 +214,6 @@ import android.content.pm.dex.ArtManager;
 import android.content.pm.dex.DexMetadataHelper;
 import android.content.pm.dex.IArtManager;
 import android.content.pm.parsing.PackageInfoWithoutStateUtils;
-import android.content.pm.parsing.ParsingPackageRead;
 import android.content.pm.parsing.ParsingPackageUtils;
 import android.content.pm.parsing.component.ParsedActivity;
 import android.content.pm.parsing.component.ParsedInstrumentation;
@@ -20169,6 +20169,7 @@ public class PackageManagerService extends IPackageManager.Stub
         }
     }
 
+    @WorkerThread
     @Override
     public void flushPackageRestrictionsAsUser(int userId) {
         if (getInstantAppPackageName(Binder.getCallingUid()) != null) {
@@ -20186,6 +20187,8 @@ public class PackageManagerService extends IPackageManager.Stub
 
     @GuardedBy("mLock")
     private void flushPackageRestrictionsAsUserInternalLocked(int userId) {
+        // NOTE: this invokes synchronous disk access, so callers using this
+        // method should consider running on a background thread
         mSettings.writePackageRestrictionsLPr(userId);
         mDirtyUsers.remove(userId);
         if (mDirtyUsers.isEmpty()) {