Handle user stopping in AppSearch.

When a user stops, we can close its AppSearchImpl instance to release
resources. We'll also remove it from our cache of unlocked users so
future API calls won't execute on a locked user.

Bug: 179407490
Test: atest --rebuild-module-info CtsAppSearchHostTestCases
Change-Id: I09953d32ad4aaf2989386e99c93623b58d564c27

apex/appsearch/service/java/com/android/server/appsearch/AppSearchManagerService.java

@@ -230,6 +230,18 @@ public class AppSearchManagerService extends SystemService {
         }
     }
 
+    @Override
+    public void onUserStopping(@NonNull TargetUser user) {
+        synchronized (mUnlockedUserIdsLocked) {
+            mUnlockedUserIdsLocked.remove(user.getUserIdentifier());
+            try {
+                mImplInstanceManager.closeAndRemoveAppSearchImplForUser(user.getUserIdentifier());
+            } catch (Throwable t) {
+                Log.e(TAG, "Error handling user stopping.", t);
+            }
+        }
+    }
+
     private void verifyUserUnlocked(int callingUserId) {
         if (isUserLocked(callingUserId)) {
             throw new IllegalStateException("User " + callingUserId + " is locked or not running.");

apex/appsearch/service/java/com/android/server/appsearch/ImplInstanceManager.java

@@ -117,10 +117,28 @@ public final class ImplInstanceManager {
      */
     public void removeAppSearchImplForUser(@UserIdInt int userId) {
         synchronized (mInstancesLocked) {
+            // no need to close and persist data to disk since we are removing them now.
             mInstancesLocked.remove(userId);
         }
     }
 
+    /**
+     * Close and remove an instance of {@link AppSearchImpl} for the given user.
+     *
+     * <p>All mutation apply to this {@link AppSearchImpl} will be persisted to disk.
+     *
+     * @param userId The multi-user userId of the user that need to be removed.
+     */
+    public void closeAndRemoveAppSearchImplForUser(@UserIdInt int userId) {
+        synchronized (mInstancesLocked) {
+            AppSearchImpl appSearchImpl = mInstancesLocked.get(userId);
+            if (appSearchImpl != null) {
+                appSearchImpl.close();
+                mInstancesLocked.remove(userId);
+            }
+        }
+    }
+
     /**
      * Gets an instance of AppSearchImpl for the given user.
      *

apex/appsearch/testing/java/com/android/server/appsearch/testing/AppSearchSessionShimImpl.java

@@ -17,6 +17,7 @@
 package com.android.server.appsearch.testing;
 
 import android.annotation.NonNull;
+import android.annotation.UserIdInt;
 import android.app.appsearch.AppSearchBatchResult;
 import android.app.appsearch.AppSearchManager;
 import android.app.appsearch.AppSearchResult;
@@ -37,6 +38,7 @@ import android.app.appsearch.SetSchemaResponse;
 import android.app.appsearch.StorageInfo;
 import android.app.appsearch.exceptions.AppSearchException;
 import android.content.Context;
+import android.os.UserHandle;
 
 import androidx.test.core.app.ApplicationProvider;
 
@@ -58,18 +60,29 @@ public class AppSearchSessionShimImpl implements AppSearchSessionShim {
     private final AppSearchSession mAppSearchSession;
     private final ExecutorService mExecutor;
 
+    /** Creates the SearchSessionShim with given SearchContext. */
     @NonNull
     public static ListenableFuture<AppSearchSessionShim> createSearchSession(
             @NonNull AppSearchManager.SearchContext searchContext) {
-        return createSearchSession(searchContext, Executors.newCachedThreadPool());
+        Context context = ApplicationProvider.getApplicationContext();
+        return createSearchSession(context, searchContext, Executors.newCachedThreadPool());
     }
 
-    /**  Creates the SearchSession with given ExecutorService. */
+    /** Creates the SearchSessionShim with given SearchContext for the given user. */
     @NonNull
     public static ListenableFuture<AppSearchSessionShim> createSearchSession(
+            @NonNull AppSearchManager.SearchContext searchContext, @UserIdInt int userId) {
+        Context context = ApplicationProvider.getApplicationContext()
+                .createContextAsUser(new UserHandle(userId), /*flags=*/ 0);
+        return createSearchSession(context, searchContext, Executors.newCachedThreadPool());
+    }
+
+    /**  Creates the SearchSession with given Context and ExecutorService. */
+    @NonNull
+    public static ListenableFuture<AppSearchSessionShim> createSearchSession(
+            @NonNull Context context,
             @NonNull AppSearchManager.SearchContext searchContext,
             @NonNull ExecutorService executor) {
-        Context context = ApplicationProvider.getApplicationContext();
         AppSearchManager appSearchManager = context.getSystemService(AppSearchManager.class);
         SettableFuture<AppSearchResult<AppSearchSession>> future = SettableFuture.create();
         appSearchManager.createSearchSession(searchContext, executor, future::set);