| // Copyright 2011 The Closure Library Authors. All Rights Reserved. |
| // |
| // 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. |
| |
| /** |
| * @fileoverview Base class that implements functionality common |
| * across both session and local web storage mechanisms. |
| * |
| */ |
| |
| goog.provide('goog.storage.mechanism.HTML5WebStorage'); |
| |
| goog.require('goog.asserts'); |
| goog.require('goog.iter.Iterator'); |
| goog.require('goog.iter.StopIteration'); |
| goog.require('goog.storage.mechanism.ErrorCode'); |
| goog.require('goog.storage.mechanism.IterableMechanism'); |
| |
| |
| |
| /** |
| * Provides a storage mechanism that uses HTML5 Web storage. |
| * |
| * @param {Storage} storage The Web storage object. |
| * @constructor |
| * @extends {goog.storage.mechanism.IterableMechanism} |
| */ |
| goog.storage.mechanism.HTML5WebStorage = function(storage) { |
| goog.storage.mechanism.HTML5WebStorage.base(this, 'constructor'); |
| |
| /** |
| * The web storage object (window.localStorage or window.sessionStorage). |
| * @private {Storage} |
| */ |
| this.storage_ = storage; |
| }; |
| goog.inherits(goog.storage.mechanism.HTML5WebStorage, |
| goog.storage.mechanism.IterableMechanism); |
| |
| |
| /** |
| * The key used to check if the storage instance is available. |
| * @private {string} |
| * @const |
| */ |
| goog.storage.mechanism.HTML5WebStorage.STORAGE_AVAILABLE_KEY_ = '__sak'; |
| |
| |
| /** |
| * Determines whether or not the mechanism is available. |
| * It works only if the provided web storage object exists and is enabled. |
| * |
| * @return {boolean} True if the mechanism is available. |
| */ |
| goog.storage.mechanism.HTML5WebStorage.prototype.isAvailable = function() { |
| if (!this.storage_) { |
| return false; |
| } |
| /** @preserveTry */ |
| try { |
| // setItem will throw an exception if we cannot access WebStorage (e.g., |
| // Safari in private mode). |
| this.storage_.setItem( |
| goog.storage.mechanism.HTML5WebStorage.STORAGE_AVAILABLE_KEY_, '1'); |
| this.storage_.removeItem( |
| goog.storage.mechanism.HTML5WebStorage.STORAGE_AVAILABLE_KEY_); |
| return true; |
| } catch (e) { |
| return false; |
| } |
| }; |
| |
| |
| /** @override */ |
| goog.storage.mechanism.HTML5WebStorage.prototype.set = function(key, value) { |
| /** @preserveTry */ |
| try { |
| // May throw an exception if storage quota is exceeded. |
| this.storage_.setItem(key, value); |
| } catch (e) { |
| // In Safari Private mode, conforming to the W3C spec, invoking |
| // Storage.prototype.setItem will allways throw a QUOTA_EXCEEDED_ERR |
| // exception. Since it's impossible to verify if we're in private browsing |
| // mode, we throw a different exception if the storage is empty. |
| if (this.storage_.length == 0) { |
| throw goog.storage.mechanism.ErrorCode.STORAGE_DISABLED; |
| } else { |
| throw goog.storage.mechanism.ErrorCode.QUOTA_EXCEEDED; |
| } |
| } |
| }; |
| |
| |
| /** @override */ |
| goog.storage.mechanism.HTML5WebStorage.prototype.get = function(key) { |
| // According to W3C specs, values can be of any type. Since we only save |
| // strings, any other type is a storage error. If we returned nulls for |
| // such keys, i.e., treated them as non-existent, this would lead to a |
| // paradox where a key exists, but it does not when it is retrieved. |
| // http://www.w3.org/TR/2009/WD-webstorage-20091029/#the-storage-interface |
| var value = this.storage_.getItem(key); |
| if (!goog.isString(value) && !goog.isNull(value)) { |
| throw goog.storage.mechanism.ErrorCode.INVALID_VALUE; |
| } |
| return value; |
| }; |
| |
| |
| /** @override */ |
| goog.storage.mechanism.HTML5WebStorage.prototype.remove = function(key) { |
| this.storage_.removeItem(key); |
| }; |
| |
| |
| /** @override */ |
| goog.storage.mechanism.HTML5WebStorage.prototype.getCount = function() { |
| return this.storage_.length; |
| }; |
| |
| |
| /** @override */ |
| goog.storage.mechanism.HTML5WebStorage.prototype.__iterator__ = function( |
| opt_keys) { |
| var i = 0; |
| var storage = this.storage_; |
| var newIter = new goog.iter.Iterator(); |
| newIter.next = function() { |
| if (i >= storage.length) { |
| throw goog.iter.StopIteration; |
| } |
| var key = goog.asserts.assertString(storage.key(i++)); |
| if (opt_keys) { |
| return key; |
| } |
| var value = storage.getItem(key); |
| // The value must exist and be a string, otherwise it is a storage error. |
| if (!goog.isString(value)) { |
| throw goog.storage.mechanism.ErrorCode.INVALID_VALUE; |
| } |
| return value; |
| }; |
| return newIter; |
| }; |
| |
| |
| /** @override */ |
| goog.storage.mechanism.HTML5WebStorage.prototype.clear = function() { |
| this.storage_.clear(); |
| }; |
| |
| |
| /** |
| * Gets the key for a given key index. If an index outside of |
| * [0..this.getCount()) is specified, this function returns null. |
| * @param {number} index A key index. |
| * @return {?string} A storage key, or null if the specified index is out of |
| * range. |
| */ |
| goog.storage.mechanism.HTML5WebStorage.prototype.key = function(index) { |
| return this.storage_.key(index); |
| }; |