gecko-dev/dom/base/IndexedDBHelper.jsm

155 строки
4.6 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict"
let DEBUG = 0;
if (DEBUG) {
debug = function (s) { dump("-*- IndexedDBHelper: " + s + "\n"); }
} else {
debug = function (s) {}
}
const Cu = Components.utils;
const Cc = Components.classes;
const Ci = Components.interfaces;
let EXPORTED_SYMBOLS = ["IndexedDBHelper"];
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Services.jsm");
function IndexedDBHelper() { }
IndexedDBHelper.prototype = {
// Cache the database
_db: null,
// Close the database
close: function close() {
if (this._db) {
this._db.close();
}
},
/**
* Open a new database.
* User has to provide createSchema and upgradeSchema.
*
* @param successCb
* Success callback to call once database is open.
* @param failureCb
* Error callback to call when an error is encountered.
*/
open: function open(aSuccessCb, aFailureCb) {
let self = this;
debug("Try to open database:" + this.dbName + " " + this.dbVersion);
let req = this.dbGlobal.mozIndexedDB.open(this.dbName, this.dbVersion);
req.onsuccess = function (event) {
debug("Opened database:" + self.dbName + " " + self.dbName);
self._db = event.target.result;
self._db.onversionchange = function(event) {
debug("WARNING: DB modified from a different window.");
}
aSuccessCb();
};
req.onupgradeneeded = function (aEvent) {
debug("Database needs upgrade:" + this.dbName + aEvent.oldVersion + aEvent.newVersion);
debug("Correct new database version:" + aEvent.newVersion == this.dbVersion);
let _db = aEvent.target.result;
switch (aEvent.oldVersion) {
case 0:
debug("New database");
self.createSchema(_db);
break;
default:
self.upgradeSchema(_db, aEvent.oldVersion, aEvent.newVersion);
break;
}
};
req.onerror = function (aEvent) {
debug("Failed to open database:" + this.dbName);
aFailureCb(aEvent.target.errorMessage);
};
req.onblocked = function (aEvent) {
debug("Opening database request is blocked.");
};
},
/**
* Use the cached DB or open a new one.
*
* @param successCb
* Success callback to call.
* @param failureCb
* Error callback to call when an error is encountered.
*/
ensureDB: function ensureDB(aSuccessCb, aFailureCb) {
if (this._db) {
debug("ensureDB: already have a database, returning early.");
aSuccessCb();
return;
}
this.open(aSuccessCb, aFailureCb);
},
/**
* Start a new transaction.
*
* @param txn_type
* Type of transaction (e.g. "readwrite")
* @param callback
* Function to call when the transaction is available. It will
* be invoked with the transaction and the 'aDBStoreName' object store.
* @param successCb
* Success callback to call on a successful transaction commit.
* The result is stored in txn.result.
* @param failureCb
* Error callback to call when an error is encountered.
*/
newTxn: function newTxn(txn_type, callback, successCb, failureCb) {
this.ensureDB(function () {
debug("Starting new transaction" + txn_type);
let txn = this._db.transaction(this.dbName, txn_type);
debug("Retrieving object store", this.dbName);
let store = txn.objectStore(this.dbStoreName);
txn.oncomplete = function (event) {
debug("Transaction complete. Returning to callback.");
successCb(txn.result);
};
txn.onabort = function (event) {
debug("Caught error on transaction");
// FIXXMEE: this will work in the future. Bug 748630
// failureCb(event.target.error.name);
failureCb("UnknownError");
};
callback(txn, store);
}.bind(this), failureCb);
},
/**
* Initialize the DB. Does not call open.
*
* @param aDBName
* DB name for the open call.
* @param aDBVersion
* Current DB version. User has to implement createSchema and upgradeSchema.
* @param aDBStoreName
* ObjectStore that is used.
* @param aGlobal
* Global object that has mozIndexedDB property.
*/
initDBHelper: function initDBHelper(aDBName, aDBVersion, aDBStoreName, aGlobal) {
this.dbName = aDBName;
this.dbVersion = aDBVersion;
this.dbStoreName = aDBStoreName;
this.dbGlobal = aGlobal;
}
}