Andreas Hocevar
132 lines
3.9 KiB
JavaScript
132 lines
3.9 KiB
JavaScript
// Copyright 2011 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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* @fileoverview Provides a convenient API for data persistence with data
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* expiration and user-initiated expired key collection.
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*
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*/
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goog.provide('goog.storage.CollectableStorage');
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goog.require('goog.array');
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goog.require('goog.iter');
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goog.require('goog.storage.ErrorCode');
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goog.require('goog.storage.ExpiringStorage');
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goog.require('goog.storage.RichStorage');
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/**
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* Provides a storage with expirning keys and a collection method.
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*
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* @param {!goog.storage.mechanism.IterableMechanism} mechanism The underlying
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* storage mechanism.
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* @constructor
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* @extends {goog.storage.ExpiringStorage}
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*/
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goog.storage.CollectableStorage = function(mechanism) {
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goog.storage.CollectableStorage.base(this, 'constructor', mechanism);
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};
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goog.inherits(goog.storage.CollectableStorage, goog.storage.ExpiringStorage);
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/**
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* Iterate over keys and returns those that expired.
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*
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* @param {goog.iter.Iterable} keys keys to iterate over.
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* @param {boolean=} opt_strict Also return invalid keys.
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* @return {!Array<string>} Keys of values that expired.
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* @private
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*/
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goog.storage.CollectableStorage.prototype.getExpiredKeys_ =
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function(keys, opt_strict) {
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var keysToRemove = [];
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goog.iter.forEach(keys, function(key) {
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// Get the wrapper.
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var wrapper;
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/** @preserveTry */
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try {
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wrapper = goog.storage.CollectableStorage.prototype.getWrapper.call(
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this, key, true);
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} catch (ex) {
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if (ex == goog.storage.ErrorCode.INVALID_VALUE) {
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// Bad wrappers are removed in strict mode.
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if (opt_strict) {
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keysToRemove.push(key);
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}
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// Skip over bad wrappers and continue.
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return;
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}
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// Unknown error, escalate.
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throw ex;
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}
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if (!goog.isDef(wrapper)) {
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// A value for a given key is no longer available. Clean it up.
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keysToRemove.push(key);
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return;
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}
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// Remove expired objects.
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if (goog.storage.ExpiringStorage.isExpired(wrapper)) {
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keysToRemove.push(key);
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// Continue with the next key.
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return;
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}
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// Objects which can't be decoded are removed in strict mode.
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if (opt_strict) {
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/** @preserveTry */
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try {
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goog.storage.RichStorage.Wrapper.unwrap(wrapper);
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} catch (ex) {
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if (ex == goog.storage.ErrorCode.INVALID_VALUE) {
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keysToRemove.push(key);
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// Skip over bad wrappers and continue.
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return;
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}
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// Unknown error, escalate.
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throw ex;
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}
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}
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}, this);
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return keysToRemove;
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};
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/**
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* Cleans up the storage by removing expired keys.
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*
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* @param {Array<string>} keys List of all keys.
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* @param {boolean=} opt_strict Also remove invalid keys.
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* @return {!Array<string>} a list of expired keys.
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* @protected
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*/
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goog.storage.CollectableStorage.prototype.collectInternal = function(
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keys, opt_strict) {
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var keysToRemove = this.getExpiredKeys_(keys, opt_strict);
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goog.array.forEach(keysToRemove, function(key) {
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goog.storage.CollectableStorage.prototype.remove.call(this, key);
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}, this);
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return keysToRemove;
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};
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/**
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* Cleans up the storage by removing expired keys.
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*
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* @param {boolean=} opt_strict Also remove invalid keys.
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*/
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goog.storage.CollectableStorage.prototype.collect = function(opt_strict) {
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this.collectInternal(this.mechanism.__iterator__(true), opt_strict);
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};
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