/**
* @license
* Copyright 2016 Google Inc.
*
* 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.
*/
goog.provide('shaka.offline.DBEngine');
goog.require('goog.asserts');
goog.require('shaka.log');
goog.require('shaka.offline.IStorageEngine');
goog.require('shaka.util.Error');
goog.require('shaka.util.Functional');
goog.require('shaka.util.PublicPromise');
/**
* This manages all operations on an IndexedDB. This wraps all operations
* in Promises. All Promises will resolve once the transaction has completed.
* Depending on the browser, this may or may not be after the data is flushed
* to disk. https://goo.gl/zMOeJc
*
* @struct
* @constructor
* @implements {shaka.offline.IStorageEngine}
*/
shaka.offline.DBEngine = function() {
goog.asserts.assert(
shaka.offline.DBEngine.isSupported(),
'DBEngine should not be called when DBEngine is not supported');
/** @private {IDBDatabase} */
this.db_ = null;
/** @private {!Array.<shaka.offline.DBEngine.Operation>} */
this.operations_ = [];
/** @private {!Object.<string, number>} */
this.currentIdMap_ = {};
};
/**
* @typedef {{
* transaction: !IDBTransaction,
* promise: !shaka.util.PublicPromise
* }}
*
* @property {!IDBTransaction} transaction
* The transaction that this operation is using.
* @property {!shaka.util.PublicPromise} promise
* The promise associated with the operation.
*/
shaka.offline.DBEngine.Operation;
/** @private {string} */
shaka.offline.DBEngine.DB_NAME_ = 'shaka_offline_db';
/** @private @const {number} */
shaka.offline.DBEngine.DB_VERSION_ = 1;
/**
* Determines if the browsers supports IndexedDB.
* @return {boolean}
*/
shaka.offline.DBEngine.isSupported = function() {
return window.indexedDB != null;
};
/**
* Delete the database. There must be no open connections to the database.
* @return {!Promise}
*/
shaka.offline.DBEngine.deleteDatabase = function() {
if (!window.indexedDB)
return Promise.resolve();
var request =
window.indexedDB.deleteDatabase(shaka.offline.DBEngine.DB_NAME_);
var p = new shaka.util.PublicPromise();
request.onsuccess = function(event) {
goog.asserts.assert(event.newVersion == null, 'Unexpected database update');
p.resolve();
};
request.onerror = shaka.offline.DBEngine.onError_.bind(null, request, p);
return p;
};
/** @override */
shaka.offline.DBEngine.prototype.initialized = function() {
return this.db_ != null;
};
/** @override */
shaka.offline.DBEngine.prototype.init = function(storeMap, opt_retryCount) {
goog.asserts.assert(!this.db_, 'Already initialized');
return this.createConnection_(storeMap, opt_retryCount).then(function() {
// For each store, get the next ID and store in the map.
var stores = Object.keys(storeMap);
return Promise.all(stores.map(function(store) {
return this.getNextId_(store).then(function(id) {
this.currentIdMap_[store] = id;
}.bind(this));
}.bind(this)));
}.bind(this));
};
/** @override */
shaka.offline.DBEngine.prototype.destroy = function() {
return Promise.all(this.operations_.map(function(op) {
try {
// If the transaction is considered finished but has not called the
// callbacks yet, it will still be in the list and this call will fail.
// Simply ignore errors.
op.transaction.abort();
} catch (e) {}
var Functional = shaka.util.Functional;
return op.promise.catch(Functional.noop);
})).then(function() {
goog.asserts.assert(this.operations_.length == 0,
'All operations should have been closed');
if (this.db_) {
this.db_.close();
this.db_ = null;
}
}.bind(this));
};
/** @override */
shaka.offline.DBEngine.prototype.get = function(storeName, key) {
var request;
return this.createTransaction_(storeName, 'readonly', function(store) {
request = store.get(key);
}).then(function() { return request.result; });
};
/** @override */
shaka.offline.DBEngine.prototype.forEach = function(storeName, callback) {
return this.createTransaction_(storeName, 'readonly', function(store) {
var request = store.openCursor();
request.onsuccess = function(event) {
var cursor = event.target.result;
if (cursor) {
callback(cursor.value);
cursor.continue();
}
};
});
};
/** @override */
shaka.offline.DBEngine.prototype.insert = function(storeName, value) {
return this.createTransaction_(storeName, 'readwrite', function(store) {
store.put(value);
});
};
/** @override */
shaka.offline.DBEngine.prototype.remove = function(storeName, key) {
return this.createTransaction_(storeName, 'readwrite', function(store) {
store.delete(key);
});
};
/** @override */
shaka.offline.DBEngine.prototype.removeKeys = function(storeName,
keys,
opt_onKeyRemoved) {
return this.createTransaction_(storeName, 'readwrite', function(store) {
for (var i = 0; i < keys.length; i++) {
var request = store.delete(keys[i]);
request.onsuccess = opt_onKeyRemoved || function(event) { };
}
});
};
/** @override */
shaka.offline.DBEngine.prototype.reserveId = function(storeName) {
goog.asserts.assert(storeName in this.currentIdMap_,
'Store name must be passed to init()');
return this.currentIdMap_[storeName]++;
};
/**
* Gets the ID to start at.
*
* @param {string} storeName
* @return {!Promise.<number>}
* @private
*/
shaka.offline.DBEngine.prototype.getNextId_ = function(storeName) {
var id = 0;
return this.createTransaction_(storeName, 'readonly', function(store) {
var request = store.openCursor(null, 'prev');
request.onsuccess = function(event) {
var cursor = event.target.result;
if (cursor) {
id = cursor.key + 1;
}
};
}).then(function() { return id; });
};
/**
* Creates a new transaction for the given store name and calls |action| to
* modify the store. The transaction will resolve or reject the promise
* returned by this function.
*
* @param {string} storeName
* @param {string} type
* @param {!function(IDBObjectStore)} action
*
* @return {!Promise}
* @private
*/
shaka.offline.DBEngine.prototype.createTransaction_ = function(storeName,
type,
action) {
goog.asserts.assert(this.db_, 'DBEngine must not be destroyed');
goog.asserts.assert(type == 'readonly' || type == 'readwrite',
'Type must be "readonly" or "readwrite"');
var op = {
transaction: this.db_.transaction([storeName], type),
promise: new shaka.util.PublicPromise()
};
op.transaction.oncomplete = (function(event) {
this.closeOperation_(op);
op.promise.resolve();
}.bind(this));
// We will see an onabort call via:
// 1. request error -> transaction error -> transaction abort
// 2. transaction commit fail -> transaction abort
// As any transaction error will result in an abort, it is better to listen
// for an abort so that we will catch all failed transaction operations.
op.transaction.onabort = (function(event) {
this.closeOperation_(op);
shaka.offline.DBEngine.onError_(op.transaction, op.promise, event);
}.bind(this));
// We need to prevent default on the onerror event or else Firefox will
// raise an error which will cause a karma failure. This will not stop the
// onabort callback from firing.
op.transaction.onerror = (function(event) {
event.preventDefault();
}.bind(this));
var store = op.transaction.objectStore(storeName);
action(store);
this.operations_.push(op);
return op.promise;
};
/**
* Close an open operation.
*
* @param {!shaka.offline.DBEngine.Operation} op
* @private
*/
shaka.offline.DBEngine.prototype.closeOperation_ = function(op) {
var i = this.operations_.indexOf(op);
goog.asserts.assert(i >= 0, 'Operation must be in the list.');
this.operations_.splice(i, 1);
};
/**
* Creates a new connection to the database.
*
* On IE/Edge, it is possible for the database to not be deleted when the
* success callback is fired. This means that when we delete the database and
* immediately create a new connection, we will connect to the old database.
* If this happens, we need to close the connection and retry.
*
* @see https://goo.gl/hOYJvN
*
* @param {!Object.<string, string>} storeMap
* @param {number=} opt_retryCount
* @return {!Promise}
* @private
*/
shaka.offline.DBEngine.prototype.createConnection_ = function(
storeMap, opt_retryCount) {
var DBEngine = shaka.offline.DBEngine;
var indexedDB = window.indexedDB;
var request = indexedDB.open(DBEngine.DB_NAME_, DBEngine.DB_VERSION_);
var upgraded = false;
var createPromise = new shaka.util.PublicPromise();
request.onupgradeneeded = function(event) {
upgraded = true;
var db = event.target.result;
goog.asserts.assert(event.oldVersion == 0,
'Must be upgrading from version 0');
goog.asserts.assert(db.objectStoreNames.length == 0,
'Version 0 database should be empty');
for (var name in storeMap) {
db.createObjectStore(name, {keyPath: storeMap[name]});
}
};
request.onsuccess = (function(event) {
if (opt_retryCount && !upgraded) {
event.target.result.close();
shaka.log.info('Didn\'t get an upgrade event... trying again.');
setTimeout(function() {
var p = this.createConnection_(storeMap, opt_retryCount - 1);
p.then(createPromise.resolve, createPromise.reject);
}.bind(this), 1000);
return;
}
goog.asserts.assert(opt_retryCount == undefined || upgraded,
'Should get upgrade event');
this.db_ = event.target.result;
createPromise.resolve();
}.bind(this));
request.onerror = DBEngine.onError_.bind(null, request, createPromise);
return createPromise;
};
/**
* Rejects the given Promise using the error fromt the transaction.
*
* @param {!IDBTransaction|!IDBRequest} errorSource
* @param {!shaka.util.PublicPromise} promise
* @param {Event} event
* @private
*/
shaka.offline.DBEngine.onError_ = function(errorSource, promise, event) {
if (errorSource.error) {
promise.reject(new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.STORAGE,
shaka.util.Error.Code.INDEXED_DB_ERROR, errorSource.error));
} else {
promise.reject(new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.STORAGE,
shaka.util.Error.Code.OPERATION_ABORTED));
}
// Firefox will raise an error which will cause a karma failure.
event.preventDefault();
};