apex/appsearch/service/java/com/android/server/appsearch/impl/AppSearchImpl.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2019 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.
  */

 package com.android.server.appsearch.impl;

 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.UserIdInt;
 import android.content.Context;
 import android.util.ArraySet;

 import com.android.internal.annotations.VisibleForTesting;

 import com.google.android.icing.proto.DocumentProto;
 import com.google.android.icing.proto.PropertyConfigProto;
 import com.google.android.icing.proto.PropertyProto;
 import com.google.android.icing.proto.ResultSpecProto;
 import com.google.android.icing.proto.SchemaProto;
 import com.google.android.icing.proto.SchemaTypeConfigProto;
 import com.google.android.icing.proto.ScoringSpecProto;
 import com.google.android.icing.proto.SearchResultProto;
 import com.google.android.icing.proto.SearchSpecProto;

 import java.util.Set;

 /**
  * Manages interaction with {@link FakeIcing} and other components to implement AppSearch
  * functionality.
  */
 public final class AppSearchImpl {
     private final Context mContext;
     private final @UserIdInt int mUserId;
     private final FakeIcing mFakeIcing = new FakeIcing();

     AppSearchImpl(@NonNull Context context, @UserIdInt int userId) {
         mContext = context;
         mUserId = userId;
     }

     /**
      * Updates the AppSearch schema for this app.
      *
      * @param callingUid The uid of the app calling AppSearch.
      * @param origSchema The schema to set for this app.
      * @param forceOverride Whether to force-apply the schema even if it is incompatible. Documents
      *     which do not comply with the new schema will be deleted.
      */
     public void setSchema(int callingUid, @NonNull SchemaProto origSchema, boolean forceOverride) {
         // Rewrite schema type names to include the calling app's package and uid.
         String typePrefix = getTypePrefix(callingUid);
         SchemaProto.Builder schemaBuilder = origSchema.toBuilder();
         rewriteSchemaTypes(typePrefix, schemaBuilder);

         // TODO(b/145635424): Save in schema type map
         // TODO(b/145635424): Apply the schema to Icing and report results
     }

     /**
      * Rewrites all types mentioned in the given {@code schemaBuilder} to prepend
      * {@code typePrefix}.
      *
      * @param typePrefix The prefix to add
      * @param schemaBuilder The schema to mutate
      */
     @VisibleForTesting
     void rewriteSchemaTypes(
             @NonNull String typePrefix, @NonNull SchemaProto.Builder schemaBuilder) {
         for (int typeIdx = 0; typeIdx < schemaBuilder.getTypesCount(); typeIdx++) {
             SchemaTypeConfigProto.Builder typeConfigBuilder =
                     schemaBuilder.getTypes(typeIdx).toBuilder();

             // Rewrite SchemaProto.types.schema_type
             String newSchemaType = typePrefix + typeConfigBuilder.getSchemaType();
             typeConfigBuilder.setSchemaType(newSchemaType);

             // Rewrite SchemaProto.types.properties.schema_type
             for (int propertyIdx = 0;
                     propertyIdx < typeConfigBuilder.getPropertiesCount();
                     propertyIdx++) {
                 PropertyConfigProto.Builder propertyConfigBuilder =
                         typeConfigBuilder.getProperties(propertyIdx).toBuilder();
                 if (!propertyConfigBuilder.getSchemaType().isEmpty()) {
                     String newPropertySchemaType =
                             typePrefix + propertyConfigBuilder.getSchemaType();
                     propertyConfigBuilder.setSchemaType(newPropertySchemaType);
                     typeConfigBuilder.setProperties(propertyIdx, propertyConfigBuilder);
                 }
             }

             schemaBuilder.setTypes(typeIdx, typeConfigBuilder);
         }
     }

     /**
      * Adds a document to the AppSearch index.
      *
      * @param callingUid The uid of the app calling AppSearch.
      * @param origDocument The document to index.
      */
     public void putDocument(int callingUid, @NonNull DocumentProto origDocument) {
         // Rewrite the type names to include the app's prefix
         String typePrefix = getTypePrefix(callingUid);
         DocumentProto.Builder documentBuilder = origDocument.toBuilder();
         rewriteDocumentTypes(typePrefix, documentBuilder, /*add=*/ true);
         mFakeIcing.put(documentBuilder.build());
     }

     /**
      * Retrieves a document from the AppSearch index by URI.
      *
      * @param callingUid The uid of the app calling AppSearch.
      * @param uri The URI of the document to get.
      * @return The Document contents, or {@code null} if no such URI exists in the system.
      */
     @Nullable
     public DocumentProto getDocument(int callingUid, @NonNull String uri) {
         String typePrefix = getTypePrefix(callingUid);
         DocumentProto document = mFakeIcing.get(uri);
         if (document == null) {
             return null;
         }

         // TODO(b/146526096): Since FakeIcing doesn't currently handle namespaces, we perform a
         //  post-filter to make sure we don't return documents we shouldn't. This should be removed
         //  once the real Icing Lib is implemented.
         if (!document.getNamespace().equals(typePrefix)) {
             return null;
         }

         // Rewrite the type names to remove the app's prefix
         DocumentProto.Builder documentBuilder = document.toBuilder();
         rewriteDocumentTypes(typePrefix, documentBuilder, /*add=*/ false);
         return documentBuilder.build();
     }

     /**
      * Executes a query against the AppSearch index and returns results.
      *
      * @param callingUid The uid of the app calling AppSearch.
      * @param searchSpec Defines what and how to search
      * @param resultSpec Defines what results to show
      * @param scoringSpec Defines how to order results
      * @return The results of performing this search  The proto might have no {@code results} if no
      *     documents matched the query.
      */
     @NonNull
     public SearchResultProto query(
             int callingUid,
             @NonNull SearchSpecProto searchSpec,
             @NonNull ResultSpecProto resultSpec,
             @NonNull ScoringSpecProto scoringSpec) {
         String typePrefix = getTypePrefix(callingUid);
         SearchResultProto searchResults = mFakeIcing.query(searchSpec.getQuery());
         if (searchResults.getResultsCount() == 0) {
             return searchResults;
         }
         Set<String> qualifiedSearchFilters = null;
         if (searchSpec.getSchemaTypeFiltersCount() > 0) {
             qualifiedSearchFilters = new ArraySet<>(searchSpec.getSchemaTypeFiltersCount());
             for (String schema : searchSpec.getSchemaTypeFiltersList()) {
                 String qualifiedSchema = typePrefix + schema;
                 qualifiedSearchFilters.add(qualifiedSchema);
             }
         }
         // Rewrite the type names to remove the app's prefix
         SearchResultProto.Builder searchResultsBuilder = searchResults.toBuilder();
         for (int i = 0; i < searchResultsBuilder.getResultsCount(); i++) {
             if (searchResults.getResults(i).hasDocument()) {
                 SearchResultProto.ResultProto.Builder resultBuilder =
                         searchResultsBuilder.getResults(i).toBuilder();

                 // TODO(b/145631811): Since FakeIcing doesn't currently handle namespaces, we
                 //  perform a post-filter to make sure we don't return documents we shouldn't. This
                 //  should be removed once the real Icing Lib is implemented.
                 if (!resultBuilder.getDocument().getNamespace().equals(typePrefix)) {
                     searchResultsBuilder.removeResults(i);
                     i--;
                     continue;
                 }

                 // TODO(b/145631811): Since FakeIcing doesn't currently handle type names, we
                 //  perform a post-filter to make sure we don't return documents we shouldn't. This
                 //  should be removed once the real Icing Lib is implemented.
                 if (qualifiedSearchFilters != null
                         && !qualifiedSearchFilters.contains(
                                 resultBuilder.getDocument().getSchema())) {
                     searchResultsBuilder.removeResults(i);
                     i--;
                     continue;
                 }

                 DocumentProto.Builder documentBuilder = resultBuilder.getDocument().toBuilder();
                 rewriteDocumentTypes(typePrefix, documentBuilder, /*add=*/false);
                 resultBuilder.setDocument(documentBuilder);
                 searchResultsBuilder.setResults(i, resultBuilder);
             }
         }
         return searchResultsBuilder.build();
     }

     /** Deletes the given document by URI */
     public boolean delete(int callingUid, @NonNull String uri) {
         DocumentProto document = mFakeIcing.get(uri);
         if (document == null) {
             return false;
         }

         // TODO(b/146526096): Since FakeIcing doesn't currently handle namespaces, we perform a
         //     post-filter to make sure we don't delete documents we shouldn't. This should be
         //     removed once the real Icing Lib is implemented.
         String typePrefix = getTypePrefix(callingUid);
         if (!typePrefix.equals(document.getNamespace())) {
             throw new SecurityException(
                     "Failed to delete document " + uri + "; URI collision in FakeIcing");
         }

         return mFakeIcing.delete(uri);
     }

     /** Deletes all documents having the given {@code schemaType}. */
     public boolean deleteByType(int callingUid, @NonNull String schemaType) {
         String typePrefix = getTypePrefix(callingUid);
         String qualifiedType = typePrefix + schemaType;
         return mFakeIcing.deleteByType(qualifiedType);
     }

     /**
      * Deletes all documents owned by the calling app.
      *
      * @param callingUid The uid of the app calling AppSearch.
      */
     public void deleteAll(int callingUid) {
         String namespace = getTypePrefix(callingUid);
         mFakeIcing.deleteByNamespace(namespace);
     }

     /**
      * Rewrites all types mentioned anywhere in {@code documentBuilder} to prepend or remove
      * {@code typePrefix}.
      *
      * @param typePrefix The prefix to add or remove
      * @param documentBuilder The document to mutate
      * @param add Whether to add typePrefix to the types. If {@code false}, typePrefix will be
      *     removed from the types.
      * @throws IllegalArgumentException If {@code add=false} and the document has a type that
      *     doesn't start with {@code typePrefix}.
      */
     @VisibleForTesting
     void rewriteDocumentTypes(
             @NonNull String typePrefix,
             @NonNull DocumentProto.Builder documentBuilder,
             boolean add) {
         // Rewrite the type name to include/remove the app's prefix
         String newSchema;
         if (add) {
             newSchema = typePrefix + documentBuilder.getSchema();
         } else {
             newSchema = removePrefix(typePrefix, documentBuilder.getSchema());
         }
         documentBuilder.setSchema(newSchema);

         // Add/remove namespace. If we ever allow users to set their own namespaces, this will have
         // to change to prepend the prefix instead of setting the whole namespace. We will also have
         // to store the namespaces in a map similar to the type map so we can rewrite queries with
         // empty namespaces.
         if (add) {
             documentBuilder.setNamespace(typePrefix);
         } else if (!documentBuilder.getNamespace().equals(typePrefix)) {
             throw new IllegalStateException(
                     "Unexpected namespace \"" + documentBuilder.getNamespace()
                             + "\" (expected \"" + typePrefix + "\")");
         } else {
             documentBuilder.clearNamespace();
         }

         // Recurse into derived documents
         for (int propertyIdx = 0;
                 propertyIdx < documentBuilder.getPropertiesCount();
                 propertyIdx++) {
             int documentCount = documentBuilder.getProperties(propertyIdx).getDocumentValuesCount();
             if (documentCount > 0) {
                 PropertyProto.Builder propertyBuilder =
                         documentBuilder.getProperties(propertyIdx).toBuilder();
                 for (int documentIdx = 0; documentIdx < documentCount; documentIdx++) {
                     DocumentProto.Builder derivedDocumentBuilder =
                             propertyBuilder.getDocumentValues(documentIdx).toBuilder();
                     rewriteDocumentTypes(typePrefix, derivedDocumentBuilder, add);
                     propertyBuilder.setDocumentValues(documentIdx, derivedDocumentBuilder);
                 }
                 documentBuilder.setProperties(propertyIdx, propertyBuilder);
             }
         }
     }

    /**
      * Returns a type prefix in a format like {@code com.example.package@1000/} or
      * {@code com.example.sharedname:5678@1000/}.
      */
     @NonNull
     private String getTypePrefix(int callingUid) {
         // For regular apps, this call will return the package name. If callingUid is an
         // android:sharedUserId, this value may be another type of name and have a :uid suffix.
         String callingUidName = mContext.getPackageManager().getNameForUid(callingUid);
         if (callingUidName == null) {
             // Not sure how this is possible --- maybe app was uninstalled?
             throw new IllegalStateException("Failed to look up package name for uid " + callingUid);
         }
         return callingUidName + "@" + mUserId + "/";
     }

     @NonNull
     private static String removePrefix(@NonNull String prefix, @NonNull String input) {
         if (!input.startsWith(prefix)) {
             throw new IllegalArgumentException(
                     "Input \"" + input + "\" does not start with \"" + prefix + "\"");
         }
         return input.substring(prefix.length());
     }
 }
	/*
	* Copyright (C) 2019 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.
	*/

	package com.android.server.appsearch.impl;

	import android.annotation.NonNull;
	import android.annotation.Nullable;
	import android.annotation.UserIdInt;
	import android.content.Context;
	import android.util.ArraySet;

	import com.android.internal.annotations.VisibleForTesting;

	import com.google.android.icing.proto.DocumentProto;
	import com.google.android.icing.proto.PropertyConfigProto;
	import com.google.android.icing.proto.PropertyProto;
	import com.google.android.icing.proto.ResultSpecProto;
	import com.google.android.icing.proto.SchemaProto;
	import com.google.android.icing.proto.SchemaTypeConfigProto;
	import com.google.android.icing.proto.ScoringSpecProto;
	import com.google.android.icing.proto.SearchResultProto;
	import com.google.android.icing.proto.SearchSpecProto;

	import java.util.Set;

	/**
	* Manages interaction with {@link FakeIcing} and other components to implement AppSearch
	* functionality.
	*/
	public final class AppSearchImpl {
	private final Context mContext;
	private final @UserIdInt int mUserId;
	private final FakeIcing mFakeIcing = new FakeIcing();

	AppSearchImpl(@NonNull Context context, @UserIdInt int userId) {
	mContext = context;
	mUserId = userId;
	}

	/**
	* Updates the AppSearch schema for this app.
	*
	* @param callingUid The uid of the app calling AppSearch.
	* @param origSchema The schema to set for this app.
	* @param forceOverride Whether to force-apply the schema even if it is incompatible. Documents
	* which do not comply with the new schema will be deleted.
	*/
	public void setSchema(int callingUid, @NonNull SchemaProto origSchema, boolean forceOverride) {
	// Rewrite schema type names to include the calling app's package and uid.
	String typePrefix = getTypePrefix(callingUid);
	SchemaProto.Builder schemaBuilder = origSchema.toBuilder();
	rewriteSchemaTypes(typePrefix, schemaBuilder);

	// TODO(b/145635424): Save in schema type map
	// TODO(b/145635424): Apply the schema to Icing and report results
	}

	/**
	* Rewrites all types mentioned in the given {@code schemaBuilder} to prepend
	* {@code typePrefix}.
	*
	* @param typePrefix The prefix to add
	* @param schemaBuilder The schema to mutate
	*/
	@VisibleForTesting
	void rewriteSchemaTypes(
	@NonNull String typePrefix, @NonNull SchemaProto.Builder schemaBuilder) {
	for (int typeIdx = 0; typeIdx < schemaBuilder.getTypesCount(); typeIdx++) {
	SchemaTypeConfigProto.Builder typeConfigBuilder =
	schemaBuilder.getTypes(typeIdx).toBuilder();

	// Rewrite SchemaProto.types.schema_type
	String newSchemaType = typePrefix + typeConfigBuilder.getSchemaType();
	typeConfigBuilder.setSchemaType(newSchemaType);

	// Rewrite SchemaProto.types.properties.schema_type
	for (int propertyIdx = 0;
	propertyIdx < typeConfigBuilder.getPropertiesCount();
	propertyIdx++) {
	PropertyConfigProto.Builder propertyConfigBuilder =
	typeConfigBuilder.getProperties(propertyIdx).toBuilder();
	if (!propertyConfigBuilder.getSchemaType().isEmpty()) {
	String newPropertySchemaType =
	typePrefix + propertyConfigBuilder.getSchemaType();
	propertyConfigBuilder.setSchemaType(newPropertySchemaType);
	typeConfigBuilder.setProperties(propertyIdx, propertyConfigBuilder);
	}
	}

	schemaBuilder.setTypes(typeIdx, typeConfigBuilder);
	}
	}

	/**
	* Adds a document to the AppSearch index.
	*
	* @param callingUid The uid of the app calling AppSearch.
	* @param origDocument The document to index.
	*/
	public void putDocument(int callingUid, @NonNull DocumentProto origDocument) {
	// Rewrite the type names to include the app's prefix
	String typePrefix = getTypePrefix(callingUid);
	DocumentProto.Builder documentBuilder = origDocument.toBuilder();
	rewriteDocumentTypes(typePrefix, documentBuilder, /add=/ true);
	mFakeIcing.put(documentBuilder.build());
	}

	/**
	* Retrieves a document from the AppSearch index by URI.
	*
	* @param callingUid The uid of the app calling AppSearch.
	* @param uri The URI of the document to get.
	* @return The Document contents, or {@code null} if no such URI exists in the system.
	*/
	@Nullable
	public DocumentProto getDocument(int callingUid, @NonNull String uri) {
	String typePrefix = getTypePrefix(callingUid);
	DocumentProto document = mFakeIcing.get(uri);
	if (document == null) {
	return null;
	}

	// TODO(b/146526096): Since FakeIcing doesn't currently handle namespaces, we perform a
	// post-filter to make sure we don't return documents we shouldn't. This should be removed
	// once the real Icing Lib is implemented.
	if (!document.getNamespace().equals(typePrefix)) {
	return null;
	}

	// Rewrite the type names to remove the app's prefix
	DocumentProto.Builder documentBuilder = document.toBuilder();
	rewriteDocumentTypes(typePrefix, documentBuilder, /add=/ false);
	return documentBuilder.build();
	}

	/**
	* Executes a query against the AppSearch index and returns results.
	*
	* @param callingUid The uid of the app calling AppSearch.
	* @param searchSpec Defines what and how to search
	* @param resultSpec Defines what results to show
	* @param scoringSpec Defines how to order results
	* @return The results of performing this search The proto might have no {@code results} if no
	* documents matched the query.
	*/
	@NonNull
	public SearchResultProto query(
	int callingUid,
	@NonNull SearchSpecProto searchSpec,
	@NonNull ResultSpecProto resultSpec,
	@NonNull ScoringSpecProto scoringSpec) {
	String typePrefix = getTypePrefix(callingUid);
	SearchResultProto searchResults = mFakeIcing.query(searchSpec.getQuery());
	if (searchResults.getResultsCount() == 0) {
	return searchResults;
	}
	Set<String> qualifiedSearchFilters = null;
	if (searchSpec.getSchemaTypeFiltersCount() > 0) {
	qualifiedSearchFilters = new ArraySet<>(searchSpec.getSchemaTypeFiltersCount());
	for (String schema : searchSpec.getSchemaTypeFiltersList()) {
	String qualifiedSchema = typePrefix + schema;
	qualifiedSearchFilters.add(qualifiedSchema);
	}
	}
	// Rewrite the type names to remove the app's prefix
	SearchResultProto.Builder searchResultsBuilder = searchResults.toBuilder();
	for (int i = 0; i < searchResultsBuilder.getResultsCount(); i++) {
	if (searchResults.getResults(i).hasDocument()) {
	SearchResultProto.ResultProto.Builder resultBuilder =
	searchResultsBuilder.getResults(i).toBuilder();

	// TODO(b/145631811): Since FakeIcing doesn't currently handle namespaces, we
	// perform a post-filter to make sure we don't return documents we shouldn't. This
	// should be removed once the real Icing Lib is implemented.
	if (!resultBuilder.getDocument().getNamespace().equals(typePrefix)) {
	searchResultsBuilder.removeResults(i);
	i--;
	continue;
	}

	// TODO(b/145631811): Since FakeIcing doesn't currently handle type names, we
	// perform a post-filter to make sure we don't return documents we shouldn't. This
	// should be removed once the real Icing Lib is implemented.
	if (qualifiedSearchFilters != null
	&& !qualifiedSearchFilters.contains(
	resultBuilder.getDocument().getSchema())) {
	searchResultsBuilder.removeResults(i);
	i--;
	continue;
	}

	DocumentProto.Builder documentBuilder = resultBuilder.getDocument().toBuilder();
	rewriteDocumentTypes(typePrefix, documentBuilder, /add=/false);
	resultBuilder.setDocument(documentBuilder);
	searchResultsBuilder.setResults(i, resultBuilder);
	}
	}
	return searchResultsBuilder.build();
	}

	/** Deletes the given document by URI */
	public boolean delete(int callingUid, @NonNull String uri) {
	DocumentProto document = mFakeIcing.get(uri);
	if (document == null) {
	return false;
	}

	// TODO(b/146526096): Since FakeIcing doesn't currently handle namespaces, we perform a
	// post-filter to make sure we don't delete documents we shouldn't. This should be
	// removed once the real Icing Lib is implemented.
	String typePrefix = getTypePrefix(callingUid);
	if (!typePrefix.equals(document.getNamespace())) {
	throw new SecurityException(
	"Failed to delete document " + uri + "; URI collision in FakeIcing");
	}

	return mFakeIcing.delete(uri);
	}

	/** Deletes all documents having the given {@code schemaType}. */
	public boolean deleteByType(int callingUid, @NonNull String schemaType) {
	String typePrefix = getTypePrefix(callingUid);
	String qualifiedType = typePrefix + schemaType;
	return mFakeIcing.deleteByType(qualifiedType);
	}

	/**
	* Deletes all documents owned by the calling app.
	*
	* @param callingUid The uid of the app calling AppSearch.
	*/
	public void deleteAll(int callingUid) {
	String namespace = getTypePrefix(callingUid);
	mFakeIcing.deleteByNamespace(namespace);
	}

	/**
	* Rewrites all types mentioned anywhere in {@code documentBuilder} to prepend or remove
	* {@code typePrefix}.
	*
	* @param typePrefix The prefix to add or remove
	* @param documentBuilder The document to mutate
	* @param add Whether to add typePrefix to the types. If {@code false}, typePrefix will be
	* removed from the types.
	* @throws IllegalArgumentException If {@code add=false} and the document has a type that
	* doesn't start with {@code typePrefix}.
	*/
	@VisibleForTesting
	void rewriteDocumentTypes(
	@NonNull String typePrefix,
	@NonNull DocumentProto.Builder documentBuilder,
	boolean add) {
	// Rewrite the type name to include/remove the app's prefix
	String newSchema;
	if (add) {
	newSchema = typePrefix + documentBuilder.getSchema();
	} else {
	newSchema = removePrefix(typePrefix, documentBuilder.getSchema());
	}
	documentBuilder.setSchema(newSchema);

	// Add/remove namespace. If we ever allow users to set their own namespaces, this will have
	// to change to prepend the prefix instead of setting the whole namespace. We will also have
	// to store the namespaces in a map similar to the type map so we can rewrite queries with
	// empty namespaces.
	if (add) {
	documentBuilder.setNamespace(typePrefix);
	} else if (!documentBuilder.getNamespace().equals(typePrefix)) {
	throw new IllegalStateException(
	"Unexpected namespace \"" + documentBuilder.getNamespace()
	+ "\" (expected \"" + typePrefix + "\")");
	} else {
	documentBuilder.clearNamespace();
	}

	// Recurse into derived documents
	for (int propertyIdx = 0;
	propertyIdx < documentBuilder.getPropertiesCount();
	propertyIdx++) {
	int documentCount = documentBuilder.getProperties(propertyIdx).getDocumentValuesCount();
	if (documentCount > 0) {
	PropertyProto.Builder propertyBuilder =
	documentBuilder.getProperties(propertyIdx).toBuilder();
	for (int documentIdx = 0; documentIdx < documentCount; documentIdx++) {
	DocumentProto.Builder derivedDocumentBuilder =
	propertyBuilder.getDocumentValues(documentIdx).toBuilder();
	rewriteDocumentTypes(typePrefix, derivedDocumentBuilder, add);
	propertyBuilder.setDocumentValues(documentIdx, derivedDocumentBuilder);
	}
	documentBuilder.setProperties(propertyIdx, propertyBuilder);
	}
	}
	}

	/**
	* Returns a type prefix in a format like {@code com.example.package@1000/} or
	* {@code com.example.sharedname:5678@1000/}.
	*/
	@NonNull
	private String getTypePrefix(int callingUid) {
	// For regular apps, this call will return the package name. If callingUid is an
	// android:sharedUserId, this value may be another type of name and have a :uid suffix.
	String callingUidName = mContext.getPackageManager().getNameForUid(callingUid);
	if (callingUidName == null) {
	// Not sure how this is possible --- maybe app was uninstalled?
	throw new IllegalStateException("Failed to look up package name for uid " + callingUid);
	}
	return callingUidName + "@" + mUserId + "/";
	}

	@NonNull
	private static String removePrefix(@NonNull String prefix, @NonNull String input) {
	if (!input.startsWith(prefix)) {
	throw new IllegalArgumentException(
	"Input \"" + input + "\" does not start with \"" + prefix + "\"");
	}
	return input.substring(prefix.length());
	}
	}