mirror of
https://github.com/classilla/tenfourfox.git
synced 2024-06-09 11:29:39 +00:00
104 lines
2.8 KiB
JavaScript
104 lines
2.8 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";
|
|
|
|
this.EXPORTED_SYMBOLS = ["ScrollPosition"];
|
|
|
|
const Ci = Components.interfaces;
|
|
|
|
/**
|
|
* It provides methods to collect scroll positions from single frames and to
|
|
* restore scroll positions for frame trees.
|
|
*
|
|
* This is a child process module.
|
|
*/
|
|
this.ScrollPosition = Object.freeze({
|
|
collect(frame) {
|
|
return ScrollPositionInternal.collect(frame);
|
|
},
|
|
|
|
restoreTree(root, data) {
|
|
ScrollPositionInternal.restoreTree(root, data);
|
|
}
|
|
});
|
|
|
|
/**
|
|
* This module's internal API.
|
|
*/
|
|
var ScrollPositionInternal = {
|
|
/**
|
|
* Collects scroll position data for any given |frame| in the frame hierarchy.
|
|
*
|
|
* @param frame (DOMWindow)
|
|
*
|
|
* @return {scroll: "x,y"} e.g. {scroll: "100,200"}
|
|
* Returns null when there is no scroll data we want to store for the
|
|
* given |frame|.
|
|
*/
|
|
collect: function (frame) {
|
|
let ifreq = frame.QueryInterface(Ci.nsIInterfaceRequestor);
|
|
let utils = ifreq.getInterface(Ci.nsIDOMWindowUtils);
|
|
let scrollX = {}, scrollY = {};
|
|
utils.getScrollXY(false /* no layout flush */, scrollX, scrollY);
|
|
|
|
if (scrollX.value || scrollY.value) {
|
|
return {scroll: scrollX.value + "," + scrollY.value};
|
|
}
|
|
|
|
return null;
|
|
},
|
|
|
|
/**
|
|
* Restores scroll position data for any given |frame| in the frame hierarchy.
|
|
*
|
|
* @param frame (DOMWindow)
|
|
* @param value (object, see collect())
|
|
*/
|
|
restore: function (frame, value) {
|
|
let match;
|
|
|
|
if (value && (match = /(\d+),(\d+)/.exec(value))) {
|
|
frame.scrollTo(match[1], match[2]);
|
|
}
|
|
},
|
|
|
|
/**
|
|
* Restores scroll position data for the current frame hierarchy starting at
|
|
* |root| using the given scroll position |data|.
|
|
*
|
|
* If the given |root| frame's hierarchy doesn't match that of the given
|
|
* |data| object we will silently discard data for unreachable frames. We
|
|
* may as well assign scroll positions to the wrong frames if some were
|
|
* reordered or removed.
|
|
*
|
|
* @param root (DOMWindow)
|
|
* @param data (object)
|
|
* {
|
|
* scroll: "100,200",
|
|
* children: [
|
|
* {scroll: "100,200"},
|
|
* null,
|
|
* {scroll: "200,300", children: [ ... ]}
|
|
* ]
|
|
* }
|
|
*/
|
|
restoreTree: function (root, data) {
|
|
if (data.hasOwnProperty("scroll")) {
|
|
this.restore(root, data.scroll);
|
|
}
|
|
|
|
if (!data.hasOwnProperty("children")) {
|
|
return;
|
|
}
|
|
|
|
let frames = root.frames;
|
|
data.children.forEach((child, index) => {
|
|
if (child && index < frames.length) {
|
|
this.restoreTree(frames[index], child);
|
|
}
|
|
});
|
|
}
|
|
};
|