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// 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 Provides a convenient API for data persistence with data
* expiration and user-initiated expired key collection.
*
*/
goog.provide('goog.storage.CollectableStorage');
goog.require('goog.array');
goog.require('goog.asserts');
goog.require('goog.iter');
goog.require('goog.storage.ErrorCode');
goog.require('goog.storage.ExpiringStorage');
goog.require('goog.storage.RichStorage.Wrapper');
goog.require('goog.storage.mechanism.IterableMechanism');
/**
* Provides a storage with expirning keys and a collection method.
*
* @param {!goog.storage.mechanism.IterableMechanism} mechanism The underlying
* storage mechanism.
* @constructor
* @extends {goog.storage.ExpiringStorage}
*/
goog.storage.CollectableStorage = function(mechanism) {
goog.base(this, mechanism);
};
goog.inherits(goog.storage.CollectableStorage, goog.storage.ExpiringStorage);
/**
* Cleans up the storage by removing expired keys.
*
* @param {boolean=} opt_strict Also remove invalid keys.
*/
goog.storage.CollectableStorage.prototype.collect = function(opt_strict) {
var selfObj = this;
var keysToRemove = [];
goog.iter.forEach(this.mechanism.__iterator__(true), function(key) {
// Get the wrapper.
var wrapper;
/** @preserveTry */
try {
wrapper = goog.storage.CollectableStorage.prototype.getWrapper.call(
selfObj, key, true);
} catch (ex) {
if (ex == goog.storage.ErrorCode.INVALID_VALUE) {
// Bad wrappers are removed in strict mode.
if (opt_strict) {
keysToRemove.push(key);
}
// Skip over bad wrappers and continue.
return;
}
// Unknown error, escalate.
throw ex;
}
goog.asserts.assert(wrapper);
// Remove expired objects.
if (goog.storage.ExpiringStorage.isExpired(wrapper)) {
keysToRemove.push(key);
// Continue with the next key.
return;
}
// Objects which can't be decoded are removed in strict mode.
if (opt_strict) {
/** @preserveTry */
try {
goog.storage.RichStorage.Wrapper.unwrap(wrapper);
} catch (ex) {
if (ex == goog.storage.ErrorCode.INVALID_VALUE) {
keysToRemove.push(key);
// Skip over bad wrappers and continue.
return;
}
// Unknown error, escalate.
throw ex;
}
}
});
goog.array.forEach(keysToRemove, function(key) {
goog.storage.CollectableStorage.prototype.remove.call(selfObj, key);
});
};
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