gecko-dev/toolkit/components/passwordmgr/LoginStore.jsm

310 lines
9.9 KiB
JavaScript

/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80 filetype=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/. */
/**
* Handles serialization of login-related data and persistence into a file.
*
* This modules handles the raw data stored in JavaScript serializable objects,
* and contains no special validation or query logic, that is handled entirely
* by "storage.js" instead.
*
* The data can be manipulated only after it has been loaded from disk. The
* load process can happen asynchronously, through the "load" method, or
* synchronously, through "ensureDataReady". After any modification, the
* "saveSoon" method must be called to flush the data to disk asynchronously.
*
* The raw data should be manipulated synchronously, without waiting for the
* event loop or for promise resolution, so that the saved file is always
* consistent. This synchronous approach also simplifies the query and update
* logic. For example, it is possible to find an object and modify it
* immediately without caring whether other code modifies it in the meantime.
*
* An asynchronous shutdown observer makes sure that data is always saved before
* the browser is closed. The data cannot be modified during shutdown.
*
* The file is stored in JSON format, without indentation, using UTF-8 encoding.
* With indentation applied, the file would look like this:
*
* {
* "logins": [
* {
* "id": 2,
* "hostname": "http://www.example.com",
* "httpRealm": null,
* "formSubmitURL": "http://www.example.com/submit-url",
* "usernameField": "username_field",
* "passwordField": "password_field",
* "encryptedUsername": "...",
* "encryptedPassword": "...",
* "guid": "...",
* "encType": 1,
* "timeCreated": 1262304000000,
* "timeLastUsed": 1262304000000,
* "timePasswordChanged": 1262476800000,
* "timesUsed": 1
* },
* {
* "id": 4,
* (...)
* }
* ],
* "disabledHosts": [
* "http://www.example.org",
* "http://www.example.net"
* ],
* "nextId": 10,
* "version": 1
* }
*/
"use strict";
this.EXPORTED_SYMBOLS = [
"LoginStore",
];
////////////////////////////////////////////////////////////////////////////////
//// Globals
const { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Task.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "AsyncShutdown",
"resource://gre/modules/AsyncShutdown.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "DeferredTask",
"resource://gre/modules/DeferredTask.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "FileUtils",
"resource://gre/modules/FileUtils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "OS",
"resource://gre/modules/osfile.jsm")
XPCOMUtils.defineLazyGetter(this, "gTextDecoder", function () {
return new TextDecoder();
});
XPCOMUtils.defineLazyGetter(this, "gTextEncoder", function () {
return new TextEncoder();
});
const FileInputStream =
Components.Constructor("@mozilla.org/network/file-input-stream;1",
"nsIFileInputStream", "init");
/**
* Delay between a change to the login data and the related save operation.
*/
const kSaveDelayMs = 1500;
/**
* Current data version assigned by the code that last touched the data.
*
* This number should be updated only when it is important to understand whether
* an old version of the code has touched the data, for example to execute an
* update logic. In most cases, this number should not be changed, in
* particular when no special one-time update logic is needed.
*
* For example, this number should NOT be changed when a new optional field is
* added to a login entry.
*/
const kDataVersion = 1;
////////////////////////////////////////////////////////////////////////////////
//// LoginStore
/**
* Handles serialization of login-related data and persistence into a file.
*
* @param aPath
* String containing the file path where data should be saved.
*/
function LoginStore(aPath)
{
this.path = aPath;
this._saver = new DeferredTask(() => this.save(), kSaveDelayMs);
AsyncShutdown.profileBeforeChange.addBlocker("Login store: writing data",
() => this._saver.finalize());
}
LoginStore.prototype = {
/**
* String containing the file path where data should be saved.
*/
path: "",
/**
* Serializable object containing the login-related data. This is populated
* directly with the data loaded from the file, and is saved without
* modifications.
*
* This contains one property for each list.
*/
data: null,
/**
* True when data has been loaded.
*/
dataReady: false,
/**
* Loads persistent data from the file to memory.
*
* @return {Promise}
* @resolves When the operation finished successfully.
* @rejects JavaScript exception.
*/
load: function ()
{
return Task.spawn(function () {
try {
let bytes = yield OS.File.read(this.path);
// If synchronous loading happened in the meantime, exit now.
if (this.dataReady) {
return;
}
this.data = JSON.parse(gTextDecoder.decode(bytes));
} catch (ex) {
// If an exception occurred because the file did not exist, we should
// just start with new data. Other errors may indicate that the file is
// corrupt, thus we move it to a backup location before allowing it to
// be overwritten by an empty file.
if (!(ex instanceof OS.File.Error && ex.becauseNoSuchFile)) {
Cu.reportError(ex);
// Move the original file to a backup location, ignoring errors.
try {
let openInfo = yield OS.File.openUnique(this.path + ".corrupt",
{ humanReadable: true });
yield openInfo.file.close();
yield OS.File.move(this.path, openInfo.path);
} catch (e2) {
Cu.reportError(e2);
}
}
// In some rare cases it's possible for logins to have been added to
// our database between the call to OS.File.read and when we've been
// notified that there was a problem with it. In that case, leave the
// synchronously-added data alone. See bug 1029128, comment 4.
if (this.dataReady) {
return;
}
// In any case, initialize a new object to host the data.
this.data = {
nextId: 1,
};
}
this._processLoadedData();
}.bind(this));
},
/**
* Loads persistent data from the file to memory, synchronously.
*/
ensureDataReady: function ()
{
if (this.dataReady) {
return;
}
try {
// This reads the file and automatically detects the UTF-8 encoding.
let inputStream = new FileInputStream(new FileUtils.File(this.path),
FileUtils.MODE_RDONLY,
FileUtils.PERMS_FILE, 0)
try {
let json = Cc["@mozilla.org/dom/json;1"].createInstance(Ci.nsIJSON);
this.data = json.decodeFromStream(inputStream,
inputStream.available());
} finally {
inputStream.close();
}
} catch (ex) {
// If an exception occurred because the file did not exist, we should just
// start with new data. Other errors may indicate that the file is
// corrupt, thus we move it to a backup location before allowing it to be
// overwritten by an empty file.
if (!(ex instanceof Components.Exception &&
ex.result == Cr.NS_ERROR_FILE_NOT_FOUND)) {
Cu.reportError(ex);
// Move the original file to a backup location, ignoring errors.
try {
let originalFile = new FileUtils.File(this.path);
let backupFile = originalFile.clone();
backupFile.leafName += ".corrupt";
backupFile.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE,
FileUtils.PERMS_FILE);
backupFile.remove(false);
originalFile.moveTo(backupFile.parent, backupFile.leafName);
} catch (e2) {
Cu.reportError(e2);
}
}
// In any case, initialize a new object to host the data.
this.data = {
nextId: 1,
};
}
this._processLoadedData();
},
/**
* Synchronously work on the data just loaded into memory.
*/
_processLoadedData: function ()
{
// Create any arrays that are not present in the saved file.
if (!this.data.logins) {
this.data.logins = [];
}
if (!this.data.disabledHosts) {
this.data.disabledHosts = [];
}
// Indicate that the current version of the code has touched the file.
this.data.version = kDataVersion;
this.dataReady = true;
},
/**
* Called when the data changed, this triggers asynchronous serialization.
*/
saveSoon: function () this._saver.arm(),
/**
* DeferredTask that handles the save operation.
*/
_saver: null,
/**
* Saves persistent data from memory to the file.
*
* If an error occurs, the previous file is not deleted.
*
* @return {Promise}
* @resolves When the operation finished successfully.
* @rejects JavaScript exception.
*/
save: function ()
{
return Task.spawn(function () {
// Create or overwrite the file.
let bytes = gTextEncoder.encode(JSON.stringify(this.data));
yield OS.File.writeAtomic(this.path, bytes,
{ tmpPath: this.path + ".tmp" });
}.bind(this));
},
};