browser/components/sessionstore/src/TabStateCache.jsm@6474c204b198
browser/components/sessionstore/src/TabStateCache.jsm
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
1 /* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
3 * You can obtain one at http://mozilla.org/MPL/2.0/. */
5 "use strict";
7 this.EXPORTED_SYMBOLS = ["TabStateCache"];
9 /**
10 * A cache for tabs data.
11 *
12 * This cache implements a weak map from tabs (as XUL elements)
13 * to tab data (as objects).
14 *
15 * Note that we should never cache private data, as:
16 * - that data is used very seldom by SessionStore;
17 * - caching private data in addition to public data is memory consuming.
18 */
19 this.TabStateCache = Object.freeze({
20 /**
21 * Retrieves cached data for a given |browser|.
22 *
23 * @param browser (xul:browser)
24 * The browser to retrieve cached data for.
25 * @return (object)
26 * The cached data stored for the given |browser|.
27 */
28 get: function (browser) {
29 return TabStateCacheInternal.get(browser);
30 },
32 /**
33 * Updates cached data for a given |browser|.
34 *
35 * @param browser (xul:browser)
36 * The browser belonging to the given tab data.
37 * @param newData (object)
38 * The new data to be stored for the given |browser|.
39 */
40 update: function (browser, newData) {
41 TabStateCacheInternal.update(browser, newData);
42 }
43 });
45 let TabStateCacheInternal = {
46 _data: new WeakMap(),
48 /**
49 * Retrieves cached data for a given |browser|.
50 *
51 * @param browser (xul:browser)
52 * The browser to retrieve cached data for.
53 * @return (object)
54 * The cached data stored for the given |browser|.
55 */
56 get: function (browser) {
57 return this._data.get(browser.permanentKey);
58 },
60 /**
61 * Updates cached data for a given |browser|.
62 *
63 * @param browser (xul:browser)
64 * The browser belonging to the given tab data.
65 * @param newData (object)
66 * The new data to be stored for the given |browser|.
67 */
68 update: function (browser, newData) {
69 let data = this._data.get(browser.permanentKey) || {};
71 for (let key of Object.keys(newData)) {
72 let value = newData[key];
73 if (value === null) {
74 delete data[key];
75 } else {
76 data[key] = value;
77 }
78 }
80 this._data.set(browser.permanentKey, data);
81 }
82 };
