1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/browser/components/sessionstore/src/SessionMigration.jsm Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,119 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.6 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +"use strict";
1.9 +
1.10 +this.EXPORTED_SYMBOLS = ["SessionMigration"];
1.11 +
1.12 +const Cu = Components.utils;
1.13 +Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
1.14 +Cu.import("resource://gre/modules/Task.jsm", this);
1.15 +Cu.import("resource://gre/modules/osfile.jsm", this);
1.16 +
1.17 +// An encoder to UTF-8.
1.18 +XPCOMUtils.defineLazyGetter(this, "gEncoder", function () {
1.19 + return new TextEncoder();
1.20 +});
1.21 +
1.22 +// A decoder.
1.23 +XPCOMUtils.defineLazyGetter(this, "gDecoder", function () {
1.24 + return new TextDecoder();
1.25 +});
1.26 +
1.27 +let SessionMigrationInternal = {
1.28 + /**
1.29 + * Convert the original session restore state into a minimal state. It will
1.30 + * only contain:
1.31 + * - open windows
1.32 + * - with tabs
1.33 + * - with history entries with only title, url
1.34 + * - with pinned state
1.35 + * - with tab group info (hidden + group id)
1.36 + * - with selected tab info
1.37 + * - with selected window info
1.38 + * - with tabgroups info
1.39 + *
1.40 + * The complete state is then wrapped into the "about:welcomeback" page as
1.41 + * form field info to be restored when restoring the state.
1.42 + */
1.43 + convertState: function(aStateObj) {
1.44 + let state = {
1.45 + selectedWindow: aStateObj.selectedWindow,
1.46 + _closedWindows: []
1.47 + };
1.48 + state.windows = aStateObj.windows.map(function(oldWin) {
1.49 + var win = {extData: {}};
1.50 + win.tabs = oldWin.tabs.map(function(oldTab) {
1.51 + var tab = {};
1.52 + // Keep only titles and urls for history entries
1.53 + tab.entries = oldTab.entries.map(function(entry) {
1.54 + return {url: entry.url, title: entry.title};
1.55 + });
1.56 + tab.index = oldTab.index;
1.57 + tab.hidden = oldTab.hidden;
1.58 + tab.pinned = oldTab.pinned;
1.59 + // The tabgroup info is in the extData, so we need to get it out.
1.60 + if (oldTab.extData && "tabview-tab" in oldTab.extData) {
1.61 + tab.extData = {"tabview-tab": oldTab.extData["tabview-tab"]};
1.62 + }
1.63 + return tab;
1.64 + });
1.65 + // There are various tabgroup-related attributes that we need to get out
1.66 + // of the session restore data for the window, too.
1.67 + if (oldWin.extData) {
1.68 + for (let k of Object.keys(oldWin.extData)) {
1.69 + if (k.startsWith("tabview-")) {
1.70 + win.extData[k] = oldWin.extData[k];
1.71 + }
1.72 + }
1.73 + }
1.74 + win.selected = oldWin.selected;
1.75 + win._closedTabs = [];
1.76 + return win;
1.77 + });
1.78 + let wrappedState = {
1.79 + url: "about:welcomeback",
1.80 + formdata: {
1.81 + id: {"sessionData": state},
1.82 + xpath: {}
1.83 + }
1.84 + };
1.85 + return {windows: [{tabs: [{entries: [wrappedState]}]}]};
1.86 + },
1.87 + /**
1.88 + * Asynchronously read session restore state (JSON) from a path
1.89 + */
1.90 + readState: function(aPath) {
1.91 + return Task.spawn(function() {
1.92 + let bytes = yield OS.File.read(aPath);
1.93 + let text = gDecoder.decode(bytes);
1.94 + let state = JSON.parse(text);
1.95 + throw new Task.Result(state);
1.96 + });
1.97 + },
1.98 + /**
1.99 + * Asynchronously write session restore state as JSON to a path
1.100 + */
1.101 + writeState: function(aPath, aState) {
1.102 + let bytes = gEncoder.encode(JSON.stringify(aState));
1.103 + return OS.File.writeAtomic(aPath, bytes, {tmpPath: aPath + ".tmp"});
1.104 + }
1.105 +}
1.106 +
1.107 +let SessionMigration = {
1.108 + /**
1.109 + * Migrate a limited set of session data from one path to another.
1.110 + */
1.111 + migrate: function(aFromPath, aToPath) {
1.112 + return Task.spawn(function() {
1.113 + let inState = yield SessionMigrationInternal.readState(aFromPath);
1.114 + let outState = SessionMigrationInternal.convertState(inState);
1.115 + // Unfortunately, we can't use SessionStore's own SessionFile to
1.116 + // write out the data because it has a dependency on the profile dir
1.117 + // being known. When the migration runs, there is no guarantee that
1.118 + // that's true.
1.119 + yield SessionMigrationInternal.writeState(aToPath, outState);
1.120 + });
1.121 + }
1.122 +};
