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// Copyright 2012 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 a IndexedDB cursor.
*
*/
goog.provide('goog.db.Cursor');
goog.require('goog.async.Deferred');
goog.require('goog.db.Error');
goog.require('goog.debug');
goog.require('goog.events.EventTarget');
/**
* Creates a new IDBCursor wrapper object. Should not be created directly,
* access cursor through object store.
* @see goog.db.ObjectStore#openCursor
*
* @constructor
* @extends {goog.events.EventTarget}
*/
goog.db.Cursor = function() {
goog.base(this);
};
goog.inherits(goog.db.Cursor, goog.events.EventTarget);
/**
* Underlying IndexedDB cursor object.
*
* @type {IDBCursor}
* @private
*/
goog.db.Cursor.prototype.cursor_ = null;
/**
* Advances the cursor to the next position along its direction. When new data
* is availible, the NEW_DATA event will be fired. If the cursor has reached the
* end of the range it will fire the COMPLETE event. If opt_key is specified it
* will advance to the key it matches in its direction.
*
* This wraps the native #continue method on the underlying object.
*
* @param {!Object=} opt_key The optional key to advance to.
*/
goog.db.Cursor.prototype.next = function(opt_key) {
if (opt_key) {
this.cursor_['continue'](opt_key);
} else {
this.cursor_['continue']();
}
};
/**
* Updates the value at the current position of the cursor in the object store.
* If the cursor points to a value that has just been deleted, a new value is
* created.
*
* @param {!Object} value The value to be stored.
* @return {!goog.async.Deferred} The resulting deferred request.
*/
goog.db.Cursor.prototype.update = function(value) {
var msg = 'updating via cursor with value ';
var d = new goog.async.Deferred();
var request;
try {
request = this.cursor_.update(value);
} catch (err) {
msg += goog.debug.deepExpose(value);
d.errback(new goog.db.Error(err.code, msg));
return d;
}
request.onsuccess = function(ev) {
d.callback();
};
request.onerror = function(ev) {
msg += goog.debug.deepExpose(value);
d.errback(new goog.db.Error(
(/** @type {IDBRequest} */ (ev.target)).errorCode, msg));
};
return d;
};
/**
* Deletes the value at the cursor's position, without changing the cursor's
* position. Once the value is deleted, the cursor's value is set to null.
*
* @return {!goog.async.Deferred} The resulting deferred request.
*/
goog.db.Cursor.prototype.remove = function() {
var msg = 'deleting via cursor';
var d = new goog.async.Deferred();
var request;
try {
request = this.cursor_['delete']();
} catch (err) {
d.errback(new goog.db.Error(err.code, msg));
return d;
}
request.onsuccess = function(ev) {
d.callback();
};
request.onerror = function(ev) {
d.errback(new goog.db.Error(
(/** @type {IDBRequest} */ (ev.target)).errorCode, msg));
};
return d;
};
/**
* @return {Object} The value for the value at the cursor's position. Undefined
* if no current value, or null if value has just been deleted.
*/
goog.db.Cursor.prototype.getValue = function() {
return this.cursor_['value'];
};
/**
* @return {*} The key for the value at the cursor's position. If the
* cursor is outside its range, this is undefined.
*/
goog.db.Cursor.prototype.getKey = function() {
return this.cursor_.key;
};
/**
* Possible cursor directions.
* @see http://www.w3.org/TR/IndexedDB/#idl-def-IDBCursor
*
* @enum {number}
*/
goog.db.Cursor.Direction = {
NEXT: 0,
NEXT_NO_DUPLICATE: 1,
PREV: 2,
PREV_NO_DUPLICATE: 3
};
/**
* Event types that the cursor can dispatch. COMPLETE events are dispatched when
* a cursor is depleted of values, a NEW_DATA event if there is new data
* availible, and ERROR if an error occurred.
*
* @enum {string}
*/
goog.db.Cursor.EventType = {
COMPLETE: 'c',
ERROR: 'e',
NEW_DATA: 'n'
};
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