appsearch/appsearch-local-storage/src/main/java/androidx/appsearch/localstorage/SearchSessionImpl.java - platform/frameworks/support - Git at Google

 /*
  * Copyright 2020 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 // @exportToFramework:skipFile()
 package androidx.appsearch.localstorage;

 import static androidx.appsearch.app.AppSearchResult.throwableToFailedResult;

 import android.os.SystemClock;
 import android.util.Log;

 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appsearch.app.AppSearchBatchResult;
 import androidx.appsearch.app.AppSearchSession;
 import androidx.appsearch.app.Capabilities;
 import androidx.appsearch.app.GenericDocument;
 import androidx.appsearch.app.GetByDocumentIdRequest;
 import androidx.appsearch.app.GetSchemaResponse;
 import androidx.appsearch.app.Migrator;
 import androidx.appsearch.app.PackageIdentifier;
 import androidx.appsearch.app.PutDocumentsRequest;
 import androidx.appsearch.app.RemoveByDocumentIdRequest;
 import androidx.appsearch.app.ReportUsageRequest;
 import androidx.appsearch.app.SearchResults;
 import androidx.appsearch.app.SearchSpec;
 import androidx.appsearch.app.SetSchemaRequest;
 import androidx.appsearch.app.SetSchemaResponse;
 import androidx.appsearch.app.StorageInfo;
 import androidx.appsearch.exceptions.AppSearchException;
 import androidx.appsearch.localstorage.stats.OptimizeStats;
 import androidx.appsearch.localstorage.stats.RemoveStats;
 import androidx.appsearch.localstorage.stats.SchemaMigrationStats;
 import androidx.appsearch.localstorage.stats.SetSchemaStats;
 import androidx.appsearch.localstorage.util.FutureUtil;
 import androidx.appsearch.util.SchemaMigrationUtil;
 import androidx.collection.ArrayMap;
 import androidx.collection.ArraySet;
 import androidx.core.util.Preconditions;

 import com.google.android.icing.proto.PersistType;
 import com.google.common.util.concurrent.ListenableFuture;

 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;

 /**
  * An implementation of {@link AppSearchSession} which stores data locally in the app's storage
  * space using a bundled version of the search native library.
  *
  * <p>Queries are executed multi-threaded, but a single thread is used for mutate requests (put,
  * delete, etc..).
  */
 class SearchSessionImpl implements AppSearchSession {
     private static final String TAG = "AppSearchSessionImpl";
     private final AppSearchImpl mAppSearchImpl;
     private final Executor mExecutor;
     private final Capabilities mCapabilities;
     private final String mPackageName;
     private final String mDatabaseName;
     private volatile boolean mIsMutated = false;
     private volatile boolean mIsClosed = false;
     @Nullable private final AppSearchLogger mLogger;

     SearchSessionImpl(
             @NonNull AppSearchImpl appSearchImpl,
             @NonNull Executor executor,
             @NonNull Capabilities capabilities,
             @NonNull String packageName,
             @NonNull String databaseName,
             @Nullable AppSearchLogger logger) {
         mAppSearchImpl = Preconditions.checkNotNull(appSearchImpl);
         mExecutor = Preconditions.checkNotNull(executor);
         mCapabilities = Preconditions.checkNotNull(capabilities);
         mPackageName = packageName;
         mDatabaseName = Preconditions.checkNotNull(databaseName);
         mLogger = logger;
     }

     @Override
     @NonNull
     public ListenableFuture<SetSchemaResponse> setSchema(
             @NonNull SetSchemaRequest request) {
         Preconditions.checkNotNull(request);
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");

         ListenableFuture<SetSchemaResponse> future = execute(() -> {
             long startMillis = SystemClock.elapsedRealtime();

             // Convert the inner set into a List since Binder can't handle Set.
             Map<String, Set<PackageIdentifier>> schemasVisibleToPackages =
                     request.getSchemasVisibleToPackagesInternal();
             Map<String, List<PackageIdentifier>> copySchemasVisibleToPackages = new ArrayMap<>();
             for (Map.Entry<String, Set<PackageIdentifier>> entry :
                     schemasVisibleToPackages.entrySet()) {
                 copySchemasVisibleToPackages.put(entry.getKey(),
                         new ArrayList<>(entry.getValue()));
             }

             SetSchemaStats.Builder setSchemaStatsBuilder = null;
             if (mLogger != null) {
                 setSchemaStatsBuilder = new SetSchemaStats.Builder(mPackageName, mDatabaseName);
             }

             Map<String, Migrator> migrators = request.getMigrators();
             // No need to trigger migration if user never set migrator.
             if (migrators.size() == 0) {
                 SetSchemaResponse setSchemaResponse =
                         setSchemaNoMigrations(request, copySchemasVisibleToPackages,
                                 setSchemaStatsBuilder);
                 if (setSchemaStatsBuilder != null) {
                     setSchemaStatsBuilder.setTotalLatencyMillis(
                             (int) (SystemClock.elapsedRealtime() - startMillis));
                     mLogger.logStats(setSchemaStatsBuilder.build());
                 }
                 return setSchemaResponse;
             }

             // Migration process
             // 1. Validate and retrieve all active migrators.
             GetSchemaResponse getSchemaResponse =
                     mAppSearchImpl.getSchema(mPackageName, mDatabaseName);
             int currentVersion = getSchemaResponse.getVersion();
             int finalVersion = request.getVersion();
             Map<String, Migrator> activeMigrators = SchemaMigrationUtil.getActiveMigrators(
                     getSchemaResponse.getSchemas(), migrators, currentVersion, finalVersion);
             // No need to trigger migration if no migrator is active.
             if (activeMigrators.size() == 0) {
                 SetSchemaResponse setSchemaResponse =
                         setSchemaNoMigrations(request, copySchemasVisibleToPackages,
                                 setSchemaStatsBuilder);
                 if (setSchemaStatsBuilder != null) {
                     setSchemaStatsBuilder.setTotalLatencyMillis(
                             (int) (SystemClock.elapsedRealtime() - startMillis));
                     mLogger.logStats(setSchemaStatsBuilder.build());
                 }
                 return setSchemaResponse;
             }

             // 2. SetSchema with forceOverride=false, to retrieve the list of incompatible/deleted
             // types.
             long firstSetSchemaLatencyStartMillis = SystemClock.elapsedRealtime();
             SetSchemaResponse setSchemaResponse = mAppSearchImpl.setSchema(
                     mPackageName,
                     mDatabaseName,
                     new ArrayList<>(request.getSchemas()),
                     /*visibilityStore=*/ null,
                     new ArrayList<>(request.getSchemasNotDisplayedBySystem()),
                     copySchemasVisibleToPackages,
                     /*forceOverride=*/false,
                     request.getVersion(),
                     setSchemaStatsBuilder);

             // 3. If forceOverride is false, check that all incompatible types will be migrated.
             // If some aren't we must throw an error, rather than proceeding and deleting those
             // types.
             long queryAndTransformLatencyStartMillis = SystemClock.elapsedRealtime();
             if (!request.isForceOverride()) {
                 SchemaMigrationUtil.checkDeletedAndIncompatibleAfterMigration(setSchemaResponse,
                         activeMigrators.keySet());
             }

             SchemaMigrationStats.Builder schemaMigrationStatsBuilder = null;
             if (setSchemaStatsBuilder != null) {
                 schemaMigrationStatsBuilder = new SchemaMigrationStats.Builder();
             }

             try (AppSearchMigrationHelper migrationHelper = new AppSearchMigrationHelper(
                     mAppSearchImpl, mPackageName, mDatabaseName, request.getSchemas())) {
                 // 4. Trigger migration for all activity migrators.
                 migrationHelper.queryAndTransform(activeMigrators, currentVersion, finalVersion,
                         schemaMigrationStatsBuilder);

                 // 5. SetSchema a second time with forceOverride=true if the first attempted failed
                 // due to backward incompatible changes.
                 long secondSetSchemaLatencyStartMillis = SystemClock.elapsedRealtime();
                 if (!setSchemaResponse.getIncompatibleTypes().isEmpty()
                         || !setSchemaResponse.getDeletedTypes().isEmpty()) {
                     setSchemaResponse = mAppSearchImpl.setSchema(
                             mPackageName,
                             mDatabaseName,
                             new ArrayList<>(request.getSchemas()),
                             /*visibilityStore=*/ null,
                             new ArrayList<>(request.getSchemasNotDisplayedBySystem()),
                             copySchemasVisibleToPackages,
                             /*forceOverride=*/ true,
                             request.getVersion(),
                             setSchemaStatsBuilder);
                 }
                 SetSchemaResponse.Builder responseBuilder = setSchemaResponse.toBuilder()
                         .addMigratedTypes(activeMigrators.keySet());
                 mIsMutated = true;

                 // 6. Put all the migrated documents into the index, now that the new schema is set.
                 long saveDocumentLatencyStartMillis = SystemClock.elapsedRealtime();
                 SetSchemaResponse finalSetSchemaResponse =
                         migrationHelper.readAndPutDocuments(responseBuilder,
                                 schemaMigrationStatsBuilder);

                 if (schemaMigrationStatsBuilder != null) {
                     long endMillis = SystemClock.elapsedRealtime();
                     schemaMigrationStatsBuilder
                             .setSaveDocumentLatencyMillis(
                                     (int) (endMillis - saveDocumentLatencyStartMillis))
                             .setGetSchemaLatencyMillis(
                                     (int) (firstSetSchemaLatencyStartMillis - startMillis))
                             .setFirstSetSchemaLatencyMillis(
                                     (int) (queryAndTransformLatencyStartMillis
                                             - firstSetSchemaLatencyStartMillis))
                             .setQueryAndTransformLatencyMillis(
                                     (int) (secondSetSchemaLatencyStartMillis
                                             - queryAndTransformLatencyStartMillis))
                             .setSecondSetSchemaLatencyMillis(
                                     (int) (saveDocumentLatencyStartMillis
                                             - secondSetSchemaLatencyStartMillis));
                     setSchemaStatsBuilder
                             .setSchemaMigrationStats(
                                     schemaMigrationStatsBuilder.build())
                             .setTotalLatencyMillis((int) (endMillis - startMillis));
                     mLogger.logStats(setSchemaStatsBuilder.build());
                 }

                 return finalSetSchemaResponse;
             }
         });

         // setSchema will sync the schemas in the request to AppSearch, any existing schemas which
         // is not included in the request will be delete if we force override incompatible schemas.
         // And all documents of these types will be deleted as well. We should checkForOptimize for
         // these deletion.
         checkForOptimize();
         return future;
     }

     @Override
     @NonNull
     public ListenableFuture<GetSchemaResponse> getSchema() {
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
         return execute(() -> mAppSearchImpl.getSchema(mPackageName, mDatabaseName));
     }

     @NonNull
     @Override
     public ListenableFuture<Set<String>> getNamespaces() {
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
         return execute(() -> {
             List<String> namespaces = mAppSearchImpl.getNamespaces(mPackageName, mDatabaseName);
             return new ArraySet<>(namespaces);
         });
     }

     @Override
     @NonNull
     public ListenableFuture<AppSearchBatchResult<String, Void>> put(
             @NonNull PutDocumentsRequest request) {
         Preconditions.checkNotNull(request);
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
         ListenableFuture<AppSearchBatchResult<String, Void>> future = execute(() -> {
             AppSearchBatchResult.Builder<String, Void> resultBuilder =
                     new AppSearchBatchResult.Builder<>();
             for (int i = 0; i < request.getGenericDocuments().size(); i++) {
                 GenericDocument document = request.getGenericDocuments().get(i);
                 try {
                     mAppSearchImpl.putDocument(mPackageName, mDatabaseName, document, mLogger);
                     resultBuilder.setSuccess(document.getId(), /*value=*/ null);
                 } catch (Throwable t) {
                     resultBuilder.setResult(document.getId(), throwableToFailedResult(t));
                 }
             }
             // Now that the batch has been written. Persist the newly written data.
             mAppSearchImpl.persistToDisk(PersistType.Code.LITE);
             mIsMutated = true;
             return resultBuilder.build();
         });

         // The existing documents with same ID will be deleted, so there may be some resources that
         // could be released after optimize().
         checkForOptimize(/*mutateBatchSize=*/ request.getGenericDocuments().size());
         return future;
     }

     @Override
     @NonNull
     public ListenableFuture<AppSearchBatchResult<String, GenericDocument>> getByDocumentId(
             @NonNull GetByDocumentIdRequest request) {
         Preconditions.checkNotNull(request);
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
         return execute(() -> {
             AppSearchBatchResult.Builder<String, GenericDocument> resultBuilder =
                     new AppSearchBatchResult.Builder<>();

             Map<String, List<String>> typePropertyPaths = request.getProjectionsInternal();
             for (String id : request.getIds()) {
                 try {
                     GenericDocument document =
                             mAppSearchImpl.getDocument(mPackageName, mDatabaseName,
                                     request.getNamespace(), id, typePropertyPaths);
                     resultBuilder.setSuccess(id, document);
                 } catch (Throwable t) {
                     resultBuilder.setResult(id, throwableToFailedResult(t));
                 }
             }
             return resultBuilder.build();
         });
     }

     @Override
     @NonNull
     public SearchResults search(
             @NonNull String queryExpression,
             @NonNull SearchSpec searchSpec) {
         Preconditions.checkNotNull(queryExpression);
         Preconditions.checkNotNull(searchSpec);
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
         return new SearchResultsImpl(
                 mAppSearchImpl,
                 mExecutor,
                 mPackageName,
                 mDatabaseName,
                 queryExpression,
                 searchSpec,
                 mLogger);
     }

     @Override
     @NonNull
     public ListenableFuture<Void> reportUsage(@NonNull ReportUsageRequest request) {
         Preconditions.checkNotNull(request);
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
         return execute(() -> {
             mAppSearchImpl.reportUsage(
                     mPackageName,
                     mDatabaseName,
                     request.getNamespace(),
                     request.getDocumentId(),
                     request.getUsageTimestampMillis(),
                     /*systemUsage=*/ false);
             mIsMutated = true;
             return null;
         });
     }

     @Override
     @NonNull
     public ListenableFuture<AppSearchBatchResult<String, Void>> remove(
             @NonNull RemoveByDocumentIdRequest request) {
         Preconditions.checkNotNull(request);
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
         ListenableFuture<AppSearchBatchResult<String, Void>> future = execute(() -> {
             AppSearchBatchResult.Builder<String, Void> resultBuilder =
                     new AppSearchBatchResult.Builder<>();
             for (String id : request.getIds()) {
                 RemoveStats.Builder removeStatsBuilder = null;
                 if (mLogger != null) {
                     removeStatsBuilder = new RemoveStats.Builder(mPackageName, mDatabaseName);
                 }

                 try {
                     mAppSearchImpl.remove(mPackageName, mDatabaseName, request.getNamespace(), id,
                             removeStatsBuilder);
                     resultBuilder.setSuccess(id, /*value=*/null);
                 } catch (Throwable t) {
                     resultBuilder.setResult(id, throwableToFailedResult(t));
                 } finally {
                     if (mLogger != null) {
                         mLogger.logStats(removeStatsBuilder.build());
                     }
                 }
             }
             // Now that the batch has been written. Persist the newly written data.
             mAppSearchImpl.persistToDisk(PersistType.Code.LITE);
             mIsMutated = true;
             return resultBuilder.build();
         });
         checkForOptimize(/*mutateBatchSize=*/ request.getIds().size());
         return future;
     }

     @Override
     @NonNull
     public ListenableFuture<Void> remove(
             @NonNull String queryExpression, @NonNull SearchSpec searchSpec) {
         Preconditions.checkNotNull(queryExpression);
         Preconditions.checkNotNull(searchSpec);
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
         ListenableFuture<Void> future = execute(() -> {
             RemoveStats.Builder removeStatsBuilder = null;
             if (mLogger != null) {
                 removeStatsBuilder = new RemoveStats.Builder(mPackageName, mDatabaseName);
             }

             mAppSearchImpl.removeByQuery(mPackageName, mDatabaseName, queryExpression,
                     searchSpec, removeStatsBuilder);
             // Now that the batch has been written. Persist the newly written data.
             mAppSearchImpl.persistToDisk(PersistType.Code.LITE);
             mIsMutated = true;

             if (mLogger != null) {
                 mLogger.logStats(removeStatsBuilder.build());
             }

             return null;
         });
         checkForOptimize();
         return future;
     }

     @Override
     @NonNull
     public ListenableFuture<StorageInfo> getStorageInfo() {
         Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
         return execute(() -> mAppSearchImpl.getStorageInfoForDatabase(mPackageName, mDatabaseName));
     }

     @NonNull
     @Override
     public ListenableFuture<Void> requestFlush() {
         return execute(() -> {
             mAppSearchImpl.persistToDisk(PersistType.Code.FULL);
             return null;
         });
     }

     @NonNull
     @Override
     public Capabilities getCapabilities() {
         return mCapabilities;
     }

     @Override
     @SuppressWarnings("FutureReturnValueIgnored")
     public void close() {
         if (mIsMutated && !mIsClosed) {
             // No future is needed here since the method is void.
             FutureUtil.execute(mExecutor, () -> {
                 mAppSearchImpl.persistToDisk(PersistType.Code.FULL);
                 mIsClosed = true;
                 return null;
             });
         }
     }

     private <T> ListenableFuture<T> execute(Callable<T> callable) {
         return FutureUtil.execute(mExecutor, callable);
     }

     /**
      * Set schema to Icing for no-migration scenario.
      *
      * <p>We only need one time {@link #setSchema} call for no-migration scenario by using the
      * forceoverride in the request.
      */
     private SetSchemaResponse setSchemaNoMigrations(@NonNull SetSchemaRequest request,
             @NonNull Map<String, List<PackageIdentifier>> copySchemasVisibleToPackages,
             SetSchemaStats.Builder setSchemaStatsBuilder)
             throws AppSearchException {
         SetSchemaResponse setSchemaResponse = mAppSearchImpl.setSchema(
                 mPackageName,
                 mDatabaseName,
                 new ArrayList<>(request.getSchemas()),
                 /*visibilityStore=*/ null,
                 new ArrayList<>(request.getSchemasNotDisplayedBySystem()),
                 copySchemasVisibleToPackages,
                 request.isForceOverride(),
                 request.getVersion(),
                 setSchemaStatsBuilder);
         if (!request.isForceOverride()) {
             // check both deleted types and incompatible types are empty. That's the only case we
             // swallowed in the AppSearchImpl#setSchema().
             SchemaMigrationUtil.checkDeletedAndIncompatible(setSchemaResponse.getDeletedTypes(),
                     setSchemaResponse.getIncompatibleTypes());
         }
         mIsMutated = true;
         return setSchemaResponse;
     }

     private void checkForOptimize(int mutateBatchSize) {
         mExecutor.execute(() -> {
             long totalLatencyStartMillis = SystemClock.elapsedRealtime();
             OptimizeStats.Builder builder = null;
             try {
                 if (mLogger != null) {
                     builder = new OptimizeStats.Builder();
                 }
                 mAppSearchImpl.checkForOptimize(mutateBatchSize, builder);
             } catch (AppSearchException e) {
                 Log.w(TAG, "Error occurred when check for optimize", e);
             } finally {
                 if (builder != null) {
                     OptimizeStats oStats = builder
                             .setTotalLatencyMillis(
                                     (int) (SystemClock.elapsedRealtime() - totalLatencyStartMillis))
                             .build();
                     if (mLogger != null && oStats.getOriginalDocumentCount() > 0) {
                         // see if optimize has been run by checking originalDocumentCount
                         mLogger.logStats(oStats);
                     }
                 }
             }
         });
     }

     private void checkForOptimize() {
         mExecutor.execute(() -> {
             long totalLatencyStartMillis = SystemClock.elapsedRealtime();
             OptimizeStats.Builder builder = null;
             try {
                 if (mLogger != null) {
                     builder = new OptimizeStats.Builder();
                 }
                 mAppSearchImpl.checkForOptimize(builder);
             } catch (AppSearchException e) {
                 Log.w(TAG, "Error occurred when check for optimize", e);
             } finally {
                 if (builder != null) {
                     OptimizeStats oStats = builder
                             .setTotalLatencyMillis(
                                     (int) (SystemClock.elapsedRealtime() - totalLatencyStartMillis))
                             .build();
                     if (mLogger != null && oStats.getOriginalDocumentCount() > 0) {
                         // see if optimize has been run by checking originalDocumentCount
                         mLogger.logStats(oStats);
                     }
                 }
             }
         });
     }
 }
	/*
	* Copyright 2020 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	// @exportToFramework:skipFile()
	package androidx.appsearch.localstorage;

	import static androidx.appsearch.app.AppSearchResult.throwableToFailedResult;

	import android.os.SystemClock;
	import android.util.Log;

	import androidx.annotation.NonNull;
	import androidx.annotation.Nullable;
	import androidx.appsearch.app.AppSearchBatchResult;
	import androidx.appsearch.app.AppSearchSession;
	import androidx.appsearch.app.Capabilities;
	import androidx.appsearch.app.GenericDocument;
	import androidx.appsearch.app.GetByDocumentIdRequest;
	import androidx.appsearch.app.GetSchemaResponse;
	import androidx.appsearch.app.Migrator;
	import androidx.appsearch.app.PackageIdentifier;
	import androidx.appsearch.app.PutDocumentsRequest;
	import androidx.appsearch.app.RemoveByDocumentIdRequest;
	import androidx.appsearch.app.ReportUsageRequest;
	import androidx.appsearch.app.SearchResults;
	import androidx.appsearch.app.SearchSpec;
	import androidx.appsearch.app.SetSchemaRequest;
	import androidx.appsearch.app.SetSchemaResponse;
	import androidx.appsearch.app.StorageInfo;
	import androidx.appsearch.exceptions.AppSearchException;
	import androidx.appsearch.localstorage.stats.OptimizeStats;
	import androidx.appsearch.localstorage.stats.RemoveStats;
	import androidx.appsearch.localstorage.stats.SchemaMigrationStats;
	import androidx.appsearch.localstorage.stats.SetSchemaStats;
	import androidx.appsearch.localstorage.util.FutureUtil;
	import androidx.appsearch.util.SchemaMigrationUtil;
	import androidx.collection.ArrayMap;
	import androidx.collection.ArraySet;
	import androidx.core.util.Preconditions;

	import com.google.android.icing.proto.PersistType;
	import com.google.common.util.concurrent.ListenableFuture;

	import java.util.ArrayList;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;
	import java.util.concurrent.Callable;
	import java.util.concurrent.Executor;

	/**
	* An implementation of {@link AppSearchSession} which stores data locally in the app's storage
	* space using a bundled version of the search native library.
	*
	* <p>Queries are executed multi-threaded, but a single thread is used for mutate requests (put,
	* delete, etc..).
	*/
	class SearchSessionImpl implements AppSearchSession {
	private static final String TAG = "AppSearchSessionImpl";
	private final AppSearchImpl mAppSearchImpl;
	private final Executor mExecutor;
	private final Capabilities mCapabilities;
	private final String mPackageName;
	private final String mDatabaseName;
	private volatile boolean mIsMutated = false;
	private volatile boolean mIsClosed = false;
	@Nullable private final AppSearchLogger mLogger;

	SearchSessionImpl(
	@NonNull AppSearchImpl appSearchImpl,
	@NonNull Executor executor,
	@NonNull Capabilities capabilities,
	@NonNull String packageName,
	@NonNull String databaseName,
	@Nullable AppSearchLogger logger) {
	mAppSearchImpl = Preconditions.checkNotNull(appSearchImpl);
	mExecutor = Preconditions.checkNotNull(executor);
	mCapabilities = Preconditions.checkNotNull(capabilities);
	mPackageName = packageName;
	mDatabaseName = Preconditions.checkNotNull(databaseName);
	mLogger = logger;
	}

	@Override
	@NonNull
	public ListenableFuture<SetSchemaResponse> setSchema(
	@NonNull SetSchemaRequest request) {
	Preconditions.checkNotNull(request);
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");

	ListenableFuture<SetSchemaResponse> future = execute(() -> {
	long startMillis = SystemClock.elapsedRealtime();

	// Convert the inner set into a List since Binder can't handle Set.
	Map<String, Set<PackageIdentifier>> schemasVisibleToPackages =
	request.getSchemasVisibleToPackagesInternal();
	Map<String, List<PackageIdentifier>> copySchemasVisibleToPackages = new ArrayMap<>();
	for (Map.Entry<String, Set<PackageIdentifier>> entry :
	schemasVisibleToPackages.entrySet()) {
	copySchemasVisibleToPackages.put(entry.getKey(),
	new ArrayList<>(entry.getValue()));
	}

	SetSchemaStats.Builder setSchemaStatsBuilder = null;
	if (mLogger != null) {
	setSchemaStatsBuilder = new SetSchemaStats.Builder(mPackageName, mDatabaseName);
	}

	Map<String, Migrator> migrators = request.getMigrators();
	// No need to trigger migration if user never set migrator.
	if (migrators.size() == 0) {
	SetSchemaResponse setSchemaResponse =
	setSchemaNoMigrations(request, copySchemasVisibleToPackages,
	setSchemaStatsBuilder);
	if (setSchemaStatsBuilder != null) {
	setSchemaStatsBuilder.setTotalLatencyMillis(
	(int) (SystemClock.elapsedRealtime() - startMillis));
	mLogger.logStats(setSchemaStatsBuilder.build());
	}
	return setSchemaResponse;
	}

	// Migration process
	// 1. Validate and retrieve all active migrators.
	GetSchemaResponse getSchemaResponse =
	mAppSearchImpl.getSchema(mPackageName, mDatabaseName);
	int currentVersion = getSchemaResponse.getVersion();
	int finalVersion = request.getVersion();
	Map<String, Migrator> activeMigrators = SchemaMigrationUtil.getActiveMigrators(
	getSchemaResponse.getSchemas(), migrators, currentVersion, finalVersion);
	// No need to trigger migration if no migrator is active.
	if (activeMigrators.size() == 0) {
	SetSchemaResponse setSchemaResponse =
	setSchemaNoMigrations(request, copySchemasVisibleToPackages,
	setSchemaStatsBuilder);
	if (setSchemaStatsBuilder != null) {
	setSchemaStatsBuilder.setTotalLatencyMillis(
	(int) (SystemClock.elapsedRealtime() - startMillis));
	mLogger.logStats(setSchemaStatsBuilder.build());
	}
	return setSchemaResponse;
	}

	// 2. SetSchema with forceOverride=false, to retrieve the list of incompatible/deleted
	// types.
	long firstSetSchemaLatencyStartMillis = SystemClock.elapsedRealtime();
	SetSchemaResponse setSchemaResponse = mAppSearchImpl.setSchema(
	mPackageName,
	mDatabaseName,
	new ArrayList<>(request.getSchemas()),
	/visibilityStore=/ null,
	new ArrayList<>(request.getSchemasNotDisplayedBySystem()),
	copySchemasVisibleToPackages,
	/forceOverride=/false,
	request.getVersion(),
	setSchemaStatsBuilder);

	// 3. If forceOverride is false, check that all incompatible types will be migrated.
	// If some aren't we must throw an error, rather than proceeding and deleting those
	// types.
	long queryAndTransformLatencyStartMillis = SystemClock.elapsedRealtime();
	if (!request.isForceOverride()) {
	SchemaMigrationUtil.checkDeletedAndIncompatibleAfterMigration(setSchemaResponse,
	activeMigrators.keySet());
	}

	SchemaMigrationStats.Builder schemaMigrationStatsBuilder = null;
	if (setSchemaStatsBuilder != null) {
	schemaMigrationStatsBuilder = new SchemaMigrationStats.Builder();
	}

	try (AppSearchMigrationHelper migrationHelper = new AppSearchMigrationHelper(
	mAppSearchImpl, mPackageName, mDatabaseName, request.getSchemas())) {
	// 4. Trigger migration for all activity migrators.
	migrationHelper.queryAndTransform(activeMigrators, currentVersion, finalVersion,
	schemaMigrationStatsBuilder);

	// 5. SetSchema a second time with forceOverride=true if the first attempted failed
	// due to backward incompatible changes.
	long secondSetSchemaLatencyStartMillis = SystemClock.elapsedRealtime();
	if (!setSchemaResponse.getIncompatibleTypes().isEmpty()
	\|\| !setSchemaResponse.getDeletedTypes().isEmpty()) {
	setSchemaResponse = mAppSearchImpl.setSchema(
	mPackageName,
	mDatabaseName,
	new ArrayList<>(request.getSchemas()),
	/visibilityStore=/ null,
	new ArrayList<>(request.getSchemasNotDisplayedBySystem()),
	copySchemasVisibleToPackages,
	/forceOverride=/ true,
	request.getVersion(),
	setSchemaStatsBuilder);
	}
	SetSchemaResponse.Builder responseBuilder = setSchemaResponse.toBuilder()
	.addMigratedTypes(activeMigrators.keySet());
	mIsMutated = true;

	// 6. Put all the migrated documents into the index, now that the new schema is set.
	long saveDocumentLatencyStartMillis = SystemClock.elapsedRealtime();
	SetSchemaResponse finalSetSchemaResponse =
	migrationHelper.readAndPutDocuments(responseBuilder,
	schemaMigrationStatsBuilder);

	if (schemaMigrationStatsBuilder != null) {
	long endMillis = SystemClock.elapsedRealtime();
	schemaMigrationStatsBuilder
	.setSaveDocumentLatencyMillis(
	(int) (endMillis - saveDocumentLatencyStartMillis))
	.setGetSchemaLatencyMillis(
	(int) (firstSetSchemaLatencyStartMillis - startMillis))
	.setFirstSetSchemaLatencyMillis(
	(int) (queryAndTransformLatencyStartMillis
	- firstSetSchemaLatencyStartMillis))
	.setQueryAndTransformLatencyMillis(
	(int) (secondSetSchemaLatencyStartMillis
	- queryAndTransformLatencyStartMillis))
	.setSecondSetSchemaLatencyMillis(
	(int) (saveDocumentLatencyStartMillis
	- secondSetSchemaLatencyStartMillis));
	setSchemaStatsBuilder
	.setSchemaMigrationStats(
	schemaMigrationStatsBuilder.build())
	.setTotalLatencyMillis((int) (endMillis - startMillis));
	mLogger.logStats(setSchemaStatsBuilder.build());
	}

	return finalSetSchemaResponse;
	}
	});

	// setSchema will sync the schemas in the request to AppSearch, any existing schemas which
	// is not included in the request will be delete if we force override incompatible schemas.
	// And all documents of these types will be deleted as well. We should checkForOptimize for
	// these deletion.
	checkForOptimize();
	return future;
	}

	@Override
	@NonNull
	public ListenableFuture<GetSchemaResponse> getSchema() {
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
	return execute(() -> mAppSearchImpl.getSchema(mPackageName, mDatabaseName));
	}

	@NonNull
	@Override
	public ListenableFuture<Set<String>> getNamespaces() {
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
	return execute(() -> {
	List<String> namespaces = mAppSearchImpl.getNamespaces(mPackageName, mDatabaseName);
	return new ArraySet<>(namespaces);
	});
	}

	@Override
	@NonNull
	public ListenableFuture<AppSearchBatchResult<String, Void>> put(
	@NonNull PutDocumentsRequest request) {
	Preconditions.checkNotNull(request);
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
	ListenableFuture<AppSearchBatchResult<String, Void>> future = execute(() -> {
	AppSearchBatchResult.Builder<String, Void> resultBuilder =
	new AppSearchBatchResult.Builder<>();
	for (int i = 0; i < request.getGenericDocuments().size(); i++) {
	GenericDocument document = request.getGenericDocuments().get(i);
	try {
	mAppSearchImpl.putDocument(mPackageName, mDatabaseName, document, mLogger);
	resultBuilder.setSuccess(document.getId(), /value=/ null);
	} catch (Throwable t) {
	resultBuilder.setResult(document.getId(), throwableToFailedResult(t));
	}
	}
	// Now that the batch has been written. Persist the newly written data.
	mAppSearchImpl.persistToDisk(PersistType.Code.LITE);
	mIsMutated = true;
	return resultBuilder.build();
	});

	// The existing documents with same ID will be deleted, so there may be some resources that
	// could be released after optimize().
	checkForOptimize(/mutateBatchSize=/ request.getGenericDocuments().size());
	return future;
	}

	@Override
	@NonNull
	public ListenableFuture<AppSearchBatchResult<String, GenericDocument>> getByDocumentId(
	@NonNull GetByDocumentIdRequest request) {
	Preconditions.checkNotNull(request);
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
	return execute(() -> {
	AppSearchBatchResult.Builder<String, GenericDocument> resultBuilder =
	new AppSearchBatchResult.Builder<>();

	Map<String, List<String>> typePropertyPaths = request.getProjectionsInternal();
	for (String id : request.getIds()) {
	try {
	GenericDocument document =
	mAppSearchImpl.getDocument(mPackageName, mDatabaseName,
	request.getNamespace(), id, typePropertyPaths);
	resultBuilder.setSuccess(id, document);
	} catch (Throwable t) {
	resultBuilder.setResult(id, throwableToFailedResult(t));
	}
	}
	return resultBuilder.build();
	});
	}

	@Override
	@NonNull
	public SearchResults search(
	@NonNull String queryExpression,
	@NonNull SearchSpec searchSpec) {
	Preconditions.checkNotNull(queryExpression);
	Preconditions.checkNotNull(searchSpec);
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
	return new SearchResultsImpl(
	mAppSearchImpl,
	mExecutor,
	mPackageName,
	mDatabaseName,
	queryExpression,
	searchSpec,
	mLogger);
	}

	@Override
	@NonNull
	public ListenableFuture<Void> reportUsage(@NonNull ReportUsageRequest request) {
	Preconditions.checkNotNull(request);
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
	return execute(() -> {
	mAppSearchImpl.reportUsage(
	mPackageName,
	mDatabaseName,
	request.getNamespace(),
	request.getDocumentId(),
	request.getUsageTimestampMillis(),
	/systemUsage=/ false);
	mIsMutated = true;
	return null;
	});
	}

	@Override
	@NonNull
	public ListenableFuture<AppSearchBatchResult<String, Void>> remove(
	@NonNull RemoveByDocumentIdRequest request) {
	Preconditions.checkNotNull(request);
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
	ListenableFuture<AppSearchBatchResult<String, Void>> future = execute(() -> {
	AppSearchBatchResult.Builder<String, Void> resultBuilder =
	new AppSearchBatchResult.Builder<>();
	for (String id : request.getIds()) {
	RemoveStats.Builder removeStatsBuilder = null;
	if (mLogger != null) {
	removeStatsBuilder = new RemoveStats.Builder(mPackageName, mDatabaseName);
	}

	try {
	mAppSearchImpl.remove(mPackageName, mDatabaseName, request.getNamespace(), id,
	removeStatsBuilder);
	resultBuilder.setSuccess(id, /value=/null);
	} catch (Throwable t) {
	resultBuilder.setResult(id, throwableToFailedResult(t));
	} finally {
	if (mLogger != null) {
	mLogger.logStats(removeStatsBuilder.build());
	}
	}
	}
	// Now that the batch has been written. Persist the newly written data.
	mAppSearchImpl.persistToDisk(PersistType.Code.LITE);
	mIsMutated = true;
	return resultBuilder.build();
	});
	checkForOptimize(/mutateBatchSize=/ request.getIds().size());
	return future;
	}

	@Override
	@NonNull
	public ListenableFuture<Void> remove(
	@NonNull String queryExpression, @NonNull SearchSpec searchSpec) {
	Preconditions.checkNotNull(queryExpression);
	Preconditions.checkNotNull(searchSpec);
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
	ListenableFuture<Void> future = execute(() -> {
	RemoveStats.Builder removeStatsBuilder = null;
	if (mLogger != null) {
	removeStatsBuilder = new RemoveStats.Builder(mPackageName, mDatabaseName);
	}

	mAppSearchImpl.removeByQuery(mPackageName, mDatabaseName, queryExpression,
	searchSpec, removeStatsBuilder);
	// Now that the batch has been written. Persist the newly written data.
	mAppSearchImpl.persistToDisk(PersistType.Code.LITE);
	mIsMutated = true;

	if (mLogger != null) {
	mLogger.logStats(removeStatsBuilder.build());
	}

	return null;
	});
	checkForOptimize();
	return future;
	}

	@Override
	@NonNull
	public ListenableFuture<StorageInfo> getStorageInfo() {
	Preconditions.checkState(!mIsClosed, "AppSearchSession has already been closed");
	return execute(() -> mAppSearchImpl.getStorageInfoForDatabase(mPackageName, mDatabaseName));
	}

	@NonNull
	@Override
	public ListenableFuture<Void> requestFlush() {
	return execute(() -> {
	mAppSearchImpl.persistToDisk(PersistType.Code.FULL);
	return null;
	});
	}

	@NonNull
	@Override
	public Capabilities getCapabilities() {
	return mCapabilities;
	}

	@Override
	@SuppressWarnings("FutureReturnValueIgnored")
	public void close() {
	if (mIsMutated && !mIsClosed) {
	// No future is needed here since the method is void.
	FutureUtil.execute(mExecutor, () -> {
	mAppSearchImpl.persistToDisk(PersistType.Code.FULL);
	mIsClosed = true;
	return null;
	});
	}
	}

	private <T> ListenableFuture<T> execute(Callable<T> callable) {
	return FutureUtil.execute(mExecutor, callable);
	}

	/**
	* Set schema to Icing for no-migration scenario.
	*
	* <p>We only need one time {@link #setSchema} call for no-migration scenario by using the
	* forceoverride in the request.
	*/
	private SetSchemaResponse setSchemaNoMigrations(@NonNull SetSchemaRequest request,
	@NonNull Map<String, List<PackageIdentifier>> copySchemasVisibleToPackages,
	SetSchemaStats.Builder setSchemaStatsBuilder)
	throws AppSearchException {
	SetSchemaResponse setSchemaResponse = mAppSearchImpl.setSchema(
	mPackageName,
	mDatabaseName,
	new ArrayList<>(request.getSchemas()),
	/visibilityStore=/ null,
	new ArrayList<>(request.getSchemasNotDisplayedBySystem()),
	copySchemasVisibleToPackages,
	request.isForceOverride(),
	request.getVersion(),
	setSchemaStatsBuilder);
	if (!request.isForceOverride()) {
	// check both deleted types and incompatible types are empty. That's the only case we
	// swallowed in the AppSearchImpl#setSchema().
	SchemaMigrationUtil.checkDeletedAndIncompatible(setSchemaResponse.getDeletedTypes(),
	setSchemaResponse.getIncompatibleTypes());
	}
	mIsMutated = true;
	return setSchemaResponse;
	}

	private void checkForOptimize(int mutateBatchSize) {
	mExecutor.execute(() -> {
	long totalLatencyStartMillis = SystemClock.elapsedRealtime();
	OptimizeStats.Builder builder = null;
	try {
	if (mLogger != null) {
	builder = new OptimizeStats.Builder();
	}
	mAppSearchImpl.checkForOptimize(mutateBatchSize, builder);
	} catch (AppSearchException e) {
	Log.w(TAG, "Error occurred when check for optimize", e);
	} finally {
	if (builder != null) {
	OptimizeStats oStats = builder
	.setTotalLatencyMillis(
	(int) (SystemClock.elapsedRealtime() - totalLatencyStartMillis))
	.build();
	if (mLogger != null && oStats.getOriginalDocumentCount() > 0) {
	// see if optimize has been run by checking originalDocumentCount
	mLogger.logStats(oStats);
	}
	}
	}
	});
	}

	private void checkForOptimize() {
	mExecutor.execute(() -> {
	long totalLatencyStartMillis = SystemClock.elapsedRealtime();
	OptimizeStats.Builder builder = null;
	try {
	if (mLogger != null) {
	builder = new OptimizeStats.Builder();
	}
	mAppSearchImpl.checkForOptimize(builder);
	} catch (AppSearchException e) {
	Log.w(TAG, "Error occurred when check for optimize", e);
	} finally {
	if (builder != null) {
	OptimizeStats oStats = builder
	.setTotalLatencyMillis(
	(int) (SystemClock.elapsedRealtime() - totalLatencyStartMillis))
	.build();
	if (mLogger != null && oStats.getOriginalDocumentCount() > 0) {
	// see if optimize has been run by checking originalDocumentCount
	mLogger.logStats(oStats);
	}
	}
	}
	});
	}
	}