/**
 * @license
 * Copyright 2019 Google Inc.
 *
 * 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.
 */
import { ResourcePath } from '../model/path';
import { PersistenceTransaction } from './persistence';
import { PersistencePromise } from './persistence_promise';
/**
 * Represents a set of indexes that are used to execute queries efficiently.
 *
 * Currently the only index is a [collection id] => [parent path] index, used
 * to execute Collection Group queries.
 */
export interface IndexManager {
    /**
     * Creates an index entry mapping the collectionId (last segment of the path)
     * to the parent path (either the containing document location or the empty
     * path for root-level collections). Index entries can be retrieved via
     * getCollectionParents().
     *
     * NOTE: Currently we don't remove index entries. If this ends up being an
     * issue we can devise some sort of GC strategy.
     */
    addToCollectionParentIndex(transaction: PersistenceTransaction, collectionPath: ResourcePath): PersistencePromise<void>;
    /**
     * Retrieves all parent locations containing the given collectionId, as a
     * list of paths (each path being either a document location or the empty
     * path for a root-level collection).
     */
    getCollectionParents(transaction: PersistenceTransaction, collectionId: string): PersistencePromise<ResourcePath[]>;
}
