/**
* @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.util.Error');
goog.require('shaka.util.Functional');
goog.require('shaka.util.IDestroyable');
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.util.IDestroyable}
*/
shaka.offline.DBEngine = function() {
/** @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;
};
/**
* Gets whether the DBEngine is initialized.
*
* @return {boolean}
*/
shaka.offline.DBEngine.prototype.initialized = function() {
return this.db_ != null;
};
/**
* Initializes the database and creates and required tables.
*
* @param {!Object.<string, string>} storeMap
* A map of store name to the key path.
* @return {!Promise}
*/
shaka.offline.DBEngine.prototype.init = function(storeMap) {
goog.asserts.assert(!this.db_, 'Already initialized');
var DBEngine = shaka.offline.DBEngine;
if (!DBEngine.isSupported()) {
return Promise.reject(
new shaka.util.Error(
shaka.util.Error.Category.STORAGE,
shaka.util.Error.Code.INDEXED_DB_NOT_SUPPORTED));
}
var indexedDB = window.indexedDB;
var request = indexedDB.open(DBEngine.DB_NAME_, DBEngine.DB_VERSION_);
var promise = new shaka.util.PublicPromise();
request.onupgradeneeded = function(event) {
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) {
this.db_ = event.target.result;
promise.resolve();
}.bind(this));
request.onerror = DBEngine.onError_.bind(null, request, promise);
return promise.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() {
if (this.db_) {
this.db_.close();
this.db_ = null;
}
}.bind(this));
};
/**
* Gets the item with the given ID in the store.
*
* @param {string} storeName
* @param {number} key
* @return {!Promise.<T>}
* @template T
*/
shaka.offline.DBEngine.prototype.get = function(storeName, key) {
return this.createOperation_(storeName, 'readonly', function(store) {
return store.get(key);
});
};
/**
* Calls the given callback for each value in the store. The promise will
* resolve after all items have been traversed.
*
* @param {string} storeName
* @param {function(T)} callback
* @return {!Promise}
* @template T
*/
shaka.offline.DBEngine.prototype.forEach = function(storeName, callback) {
return this.createOperation_(storeName, 'readonly', function(store) {
return store.openCursor();
}, function(/** IDBCursor */ cursor) {
if (!cursor) return;
callback(cursor.value);
cursor.continue();
});
};
/**
* Adds or updates the given value in the store.
*
* @param {string} storeName
* @param {!Object} value
* @return {!Promise}
*/
shaka.offline.DBEngine.prototype.insert = function(storeName, value) {
return this.createOperation_(storeName, 'readwrite', function(store) {
return store.put(value);
});
};
/**
* Removes the item with the given key.
*
* @param {string} storeName
* @param {number} key
* @return {!Promise}
*/
shaka.offline.DBEngine.prototype.remove = function(storeName, key) {
return this.createOperation_(storeName, 'readwrite', function(store) {
return store.delete(key);
});
};
/**
* Removes all items for which the given predicate returns true.
*
* @param {string} storeName
* @param {function(T):boolean} callback
* @return {!Promise.<number>}
* @template T
*/
shaka.offline.DBEngine.prototype.removeWhere = function(storeName, callback) {
var async = [];
return this.createOperation_(storeName, 'readwrite', function(store) {
return store.openCursor();
}, function(/** IDBCursor */ cursor) {
if (!cursor) return;
if (callback(cursor.value)) {
var request = cursor.delete();
var p = new shaka.util.PublicPromise();
request.onsuccess = p.resolve;
request.onerror = shaka.offline.DBEngine.onError_.bind(null, request, p);
async.push(p);
}
cursor.continue();
}).then(function() {
return Promise.all(async);
}).then(function() {
return async.length;
});
};
/**
* Reserves the next ID and returns it.
*
* @param {string} storeName
* @return {number}
*/
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 ret = 0;
return this.createOperation_(storeName, 'readonly', function(store) {
return store.openCursor(null, 'prev');
}, function(/** IDBCursor */ cursor) {
if (cursor)
ret = cursor.key + 1;
}).then(function() { return ret; });
};
/**
* Creates a new transaction for the given store name and calls the given
* callback to create a request. It then wraps the given request in an
* operation and returns the resulting promise. The Promise resolves when
* the transaction is complete, which will be after opt_success is called.
*
* @param {string} storeName
* @param {string} type
* @param {function(!IDBObjectStore):!IDBRequest} createRequest
* @param {(function(*))=} opt_success The value of onsuccess for the request.
* @return {!Promise}
* @private
*/
shaka.offline.DBEngine.prototype.createOperation_ = function(
storeName, type, createRequest, opt_success) {
goog.asserts.assert(this.db_, 'Must not be destroyed');
goog.asserts.assert(type == 'readonly' || type == 'readwrite',
'Type must be "readonly" or "readwrite"');
var trans = this.db_.transaction([storeName], type);
var request = createRequest(trans.objectStore(storeName));
var p = new shaka.util.PublicPromise();
if (opt_success)
request.onsuccess = function(event) { opt_success(event.target.result); };
request.onerror = shaka.offline.DBEngine.onError_.bind(null, request, p);
var op = {transaction: trans, promise: p};
this.operations_.push(op);
// Only remove the transaction once it has completed, which may be after the
// request is complete (e.g. it may need to write to disk).
var removeOp = (function() {
var i = this.operations_.indexOf(op);
goog.asserts.assert(i >= 0, 'Operation must be in the list.');
this.operations_.splice(i, 1);
}.bind(this));
trans.oncomplete = function(event) {
removeOp();
p.resolve(request.result);
};
trans.onerror = function(event) {
removeOp();
shaka.offline.DBEngine.onError_(request, p, event);
};
return p;
};
/**
* Rejects the given Promise with an unknown error.
*
* @param {!IDBRequest} request
* @param {!shaka.util.PublicPromise} promise
* @param {Event} event
* @private
*/
shaka.offline.DBEngine.onError_ = function(request, promise, event) {
if (request.error.name == 'AbortError') {
promise.reject(new shaka.util.Error(
shaka.util.Error.Category.STORAGE,
shaka.util.Error.Code.OPERATION_ABORTED));
} else {
promise.reject(new shaka.util.Error(
shaka.util.Error.Category.STORAGE,
shaka.util.Error.Code.INDEXED_DB_ERROR, request.error));
}
// Firefox will raise an error which will cause a karma failure.
event.preventDefault();
};