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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 Wrapper for an IndexedDB index.
*
*/
goog.provide('goog.db.Index');
goog.require('goog.async.Deferred');
goog.require('goog.db.Error');
goog.require('goog.debug');
/**
* Creates an IDBIndex wrapper object. Indexes are associated with object
* stores and provide methods for looking up objects based on their non-key
* properties. Should not be created directly, access through the object store
* it belongs to.
* @see goog.db.ObjectStore#getIndex
*
* @param {!IDBIndex} index Underlying IDBIndex object.
* @constructor
*/
goog.db.Index = function(index) {
/**
* Underlying IndexedDB index object.
*
* @type {!IDBIndex}
* @private
*/
this.index_ = index;
};
/**
* @return {string} Name of the index.
*/
goog.db.Index.prototype.getName = function() {
return this.index_.name;
};
/**
* @return {string} Key path of the index.
*/
goog.db.Index.prototype.getKeyPath = function() {
return this.index_.keyPath;
};
/**
* @return {boolean} True if the index enforces that there is only one object
* for each unique value it indexes on.
*/
goog.db.Index.prototype.isUnique = function() {
return this.index_.unique;
};
/**
* Helper function for get and getKey.
*
* @param {string} fn Function name to call on the index to get the request.
* @param {string} msg Message to give to the error.
* @param {!Object} value Value to look up in the index.
* @return {!goog.async.Deferred} The resulting deferred object.
* @private
*/
goog.db.Index.prototype.get_ = function(fn, msg, value) {
var d = new goog.async.Deferred();
var request;
try {
request = this.index_[fn](value);
} catch (err) {
msg += ' with value ' + goog.debug.deepExpose(value);
d.errback(new goog.db.Error(err.code, msg));
return d;
}
request.onsuccess = function(ev) {
d.callback(ev.target.result);
};
request.onerror = function(ev) {
msg += ' with value ' + goog.debug.deepExpose(value);
d.errback(new goog.db.Error(
(/** @type {IDBRequest} */ (ev.target)).errorCode,
msg));
};
return d;
};
/**
* Fetches a single object from the object store. Even if there are multiple
* objects that match the given value, this method will get only one of them.
*
* @param {!Object} value Value to look up in the index.
* @return {!goog.async.Deferred} The deferred object that matches the value.
*/
goog.db.Index.prototype.get = function(value) {
return this.get_('get', 'getting from index ' + this.getName(), value);
};
/**
* Looks up a single object from the object store and gives back the key that
* it's listed under in the object store. Even if there are multiple objects
* that match the given value, this method will only get one of their keys.
*
* @param {!Object} value Value to look up in the index.
* @return {!goog.async.Deferred} The deferred key for the object that matches
* the value.
*/
goog.db.Index.prototype.getKey = function(value) {
return this.get_('getKey', 'getting key from index ' + this.getName(), value);
};
/**
* Helper function for getAll and getAllKeys.
*
* @param {string} fn Function name to call on the index to get the request.
* @param {string} msg Message to give to the error.
* @param {!Object=} opt_value Value to look up in the index.
* @return {!goog.async.Deferred} The resulting deferred array of objects.
* @private
*/
goog.db.Index.prototype.getAll_ = function(fn, msg, opt_value) {
// This is the most common use of IDBKeyRange. If more specific uses of
// cursors are needed then a full wrapper should be created.
var IDBKeyRange = goog.global.IDBKeyRange || goog.global.webkitIDBKeyRange;
var d = new goog.async.Deferred();
var request;
try {
if (opt_value) {
request = this.index_[fn](IDBKeyRange.bound(opt_value, opt_value));
} else {
request = this.index_[fn]();
}
} catch (err) {
if (opt_value) {
msg += ' for value ' + goog.debug.deepExpose(opt_value);
}
d.errback(new goog.db.Error(err.code, msg));
return d;
}
var result = [];
request.onsuccess = function(ev) {
var cursor = ev.target.result;
if (cursor) {
result.push(cursor.value);
cursor['continue']();
} else {
d.callback(result);
}
};
request.onerror = function(ev) {
if (opt_value) {
msg += ' for value ' + goog.debug.deepExpose(opt_value);
}
d.errback(new goog.db.Error(
(/** @type {IDBRequest} */ (ev.target)).errorCode,
msg));
};
return d;
};
/**
* Gets all indexed objects. If the value is provided, gets all indexed objects
* that match the value instead.
*
* @param {!Object=} opt_value Value to look up in the index.
* @return {!goog.async.Deferred} A deferred array of objects that match the
* value.
*/
goog.db.Index.prototype.getAll = function(opt_value) {
return this.getAll_(
'openCursor',
'getting all from index ' + this.getName(),
opt_value);
};
/**
* Gets the keys to look up all the indexed objects. If the value is provided,
* gets all keys for objects that match the value instead.
*
* @param {!Object=} opt_value Value to look up in the index.
* @return {!goog.async.Deferred} A deferred array of keys for objects that
* match the value.
*/
goog.db.Index.prototype.getAllKeys = function(opt_value) {
return this.getAll_(
'openKeyCursor',
'getting all keys from index ' + this.getName(),
opt_value);
};
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