/**
 * @license
 * Copyright 2017 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 { DocumentKeySet, DocumentSizeEntries, DocumentSizeEntry, MaybeDocumentMap, NullableMaybeDocumentMap } from '../model/collections';
import { MaybeDocument } from '../model/document';
import { DocumentKey } from '../model/document_key';
import { ObjectMap } from '../util/obj_map';
import { PersistenceTransaction } from './persistence';
import { PersistencePromise } from './persistence_promise';
/**
 * An in-memory buffer of entries to be written to a RemoteDocumentCache.
 * It can be used to batch up a set of changes to be written to the cache, but
 * additionally supports reading entries back with the `getEntry()` method,
 * falling back to the underlying RemoteDocumentCache if no entry is
 * buffered.
 *
 * Entries added to the cache *must* be read first. This is to facilitate
 * calculating the size delta of the pending changes.
 *
 * PORTING NOTE: This class was implemented then removed from other platforms.
 * If byte-counting ends up being needed on the other platforms, consider
 * porting this class as part of that implementation work.
 */
export declare abstract class RemoteDocumentChangeBuffer {
    private changes;
    protected documentSizes: ObjectMap<DocumentKey, number>;
    protected abstract getFromCache(transaction: PersistenceTransaction, documentKey: DocumentKey): PersistencePromise<DocumentSizeEntry | null>;
    protected abstract getAllFromCache(transaction: PersistenceTransaction, documentKeys: DocumentKeySet): PersistencePromise<DocumentSizeEntries>;
    protected abstract applyChanges(transaction: PersistenceTransaction): PersistencePromise<void>;
    /** Buffers a `RemoteDocumentCache.addEntry()` call. */
    addEntry(maybeDocument: MaybeDocument): void;
    /**
     * Looks up an entry in the cache. The buffered changes will first be checked,
     * and if no buffered change applies, this will forward to
     * `RemoteDocumentCache.getEntry()`.
     *
     * @param transaction The transaction in which to perform any persistence
     *     operations.
     * @param documentKey The key of the entry to look up.
     * @return The cached Document or NoDocument entry, or null if we have nothing
     * cached.
     */
    getEntry(transaction: PersistenceTransaction, documentKey: DocumentKey): PersistencePromise<MaybeDocument | null>;
    /**
     * Looks up several entries in the cache, forwarding to
     * `RemoteDocumentCache.getEntry()`.
     *
     * @param transaction The transaction in which to perform any persistence
     *     operations.
     * @param documentKeys The keys of the entries to look up.
     * @return A map of cached `Document`s or `NoDocument`s, indexed by key. If an
     *     entry cannot be found, the corresponding key will be mapped to a null
     *     value.
     */
    getEntries(transaction: PersistenceTransaction, documentKeys: DocumentKeySet): PersistencePromise<NullableMaybeDocumentMap>;
    /**
     * Applies buffered changes to the underlying RemoteDocumentCache, using
     * the provided transaction.
     */
    apply(transaction: PersistenceTransaction): PersistencePromise<void>;
    /** Helper to assert this.changes is not null and return it. */
    protected assertChanges(): MaybeDocumentMap;
}
