libdot/js/lib_storage_chrome.js

// Copyright 2012 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import {lib} from './lib.js';

/**
 * Helper to retry operations when exceeding write quota.
 *
 * @param {function(): !Promise<void>} callback The operation to (re)try.
 * @param {number=} delay How long (in msec) to sleep after quota error.
 */
async function retryQuotaErrors(callback, delay = 1000) {
  while (1) {
    try {
      await callback();
      break;
    } catch (e) {
      // Doesn't seem to be any better way of handling this.
      // https://crbug.com/764759
      if (e.message.indexOf('MAX_WRITE_OPERATIONS')) {
        console.warn(`Will retry write after exceeding quota:`, e);
        await new Promise((resolve) => setTimeout(resolve, delay));
      } else {
        throw e;
      }
    }
  }
}

/**
 * chrome.storage based class with an async interface that is interchangeable
 * with other lib.Storage.* implementations.
 */
lib.Storage.Chrome = class extends lib.Storage {
  /**
   * @param {!StorageArea} storage The backing storage.
   */
  constructor(storage) {
    super();

    this.storage_ = storage;
    this.quotaRetryDelay_ = 1000;

    storage.onChanged.addListener(this.onChanged_.bind(this));
  }

  /**
   * Called by the storage implementation when the storage is modified.
   *
   * @param {!Object<string, !StorageChange>} changes Object mapping each key
   *     that changed to its corresponding StorageChange for that item.
   */
  onChanged_(changes) {
    this.observers_.forEach((o) => o(changes));
  }

  /**
   * @return {!Promise<void>}
   * @override
   */
  async clear() {
    return this.storage_.clear();
  }

  /**
   * @param {?Array<string>} keys
   * @return {!Promise<!Object<string, *>>}
   * @override
   */
  async getItems(keys) {
    return this.storage_.get(keys);
  }

  /**
   * @param {string} key
   * @param {*} value
   * @return {!Promise<void>}
   * @override
   */
  async setItem(key, value) {
    return this.setItems({[key]: value});
  }

  /**
   * @param {!Object} obj
   * @return {!Promise<void>}
   * @override
   */
  async setItems(obj) {
    return retryQuotaErrors(
        () => this.storage_.set(obj),
        this.quotaRetryDelay_);
  }

  /**
   * @param {!Array<string>} keys
   * @return {!Promise<void>}
   * @override
   */
  async removeItems(keys) {
    return retryQuotaErrors(
        () => this.storage_.remove(keys),
        this.quotaRetryDelay_);
  }
};