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/* 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";
const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
var EXPORTED_SYMBOLS = ["PageStyleChild"];
class PageStyleChild extends JSWindowActorChild {
handleEvent(event) {
// On page show, tell the parent all of the stylesheets this document has.
if (event.type == "pageshow") {
// If we are in the topmost browsing context,
// delete the stylesheets from the previous page.
if (this.browsingContext.top === this.browsingContext) {
this.sendAsyncMessage("PageStyle:Clear");
}
let window = event.target.ownerGlobal;
window.requestIdleCallback(() => {
if (!window || window.closed) {
return;
}
let styleSheets = Array.from(this.document.styleSheets);
let filteredStyleSheets = this._filterStyleSheets(styleSheets, window);
this.sendAsyncMessage("PageStyle:Add", {
filteredStyleSheets,
authorStyleDisabled: this.docShell.contentViewer.authorStyleDisabled,
preferredStyleSheetSet: this.document.preferredStyleSheetSet,
});
});
}
}
receiveMessage(msg) {
switch (msg.name) {
// Sent when the page's enabled style sheet is changed.
case "PageStyle:Switch":
this.docShell.contentViewer.authorStyleDisabled = false;
this._switchStylesheet(msg.data.title);
break;
// Sent when "No Style" is chosen.
case "PageStyle:Disable":
this.docShell.contentViewer.authorStyleDisabled = true;
break;
}
}
/**
* Switch the stylesheet so that only the sheet with the given title is enabled.
*/
_switchStylesheet(title) {
let docStyleSheets = this.document.styleSheets;
// Does this doc contain a stylesheet with this title?
// If not, it's a subframe's stylesheet that's being changed,
// so no need to disable stylesheets here.
let docContainsStyleSheet = !title;
if (title) {
for (let docStyleSheet of docStyleSheets) {
if (docStyleSheet.title === title) {
docContainsStyleSheet = true;
break;
}
}
}
for (let docStyleSheet of docStyleSheets) {
if (docStyleSheet.title) {
if (docContainsStyleSheet) {
docStyleSheet.disabled = docStyleSheet.title !== title;
}
} else if (docStyleSheet.disabled) {
docStyleSheet.disabled = false;
}
}
}
/**
* Filter the stylesheets that actually apply to this webpage.
* @param styleSheets The list of stylesheets from the document.
* @param content The window object that the webpage lives in.
*/
_filterStyleSheets(styleSheets, content) {
let result = [];
// Only stylesheets with a title can act as an alternative stylesheet.
for (let currentStyleSheet of styleSheets) {
if (!currentStyleSheet.title) {
continue;
}
// Skip any stylesheets that don't match the screen media type.
if (currentStyleSheet.media.length) {
let mediaQueryList = currentStyleSheet.media.mediaText;
if (!content.matchMedia(mediaQueryList).matches) {
continue;
}
}
let URI;
try {
if (
!currentStyleSheet.ownerNode ||
// Special-case style nodes, which have no href.
currentStyleSheet.ownerNode.nodeName.toLowerCase() != "style"
) {
URI = Services.io.newURI(currentStyleSheet.href);
}
} catch (e) {
if (e.result != Cr.NS_ERROR_MALFORMED_URI) {
throw e;
}
continue;
}
// We won't send data URIs all of the way up to the parent, as these
// can be arbitrarily large.
let sentURI = !URI || URI.scheme == "data" ? null : URI.spec;
result.push({
title: currentStyleSheet.title,
disabled: currentStyleSheet.disabled,
href: sentURI,
});
}
return result;
}
}