gecko-dev/toolkit/content/customElements.js

80 строки
3.0 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 is loaded into all XUL windows. Wrap in a block to prevent
// leaking to window scope.
{
ChromeUtils.import("resource://gre/modules/Services.jsm");
const gXULDOMParser = new DOMParser();
gXULDOMParser.forceEnableXULXBL();
class MozXULElement extends XULElement {
/**
* Allows eager deterministic construction of XUL elements with XBL attached, by
* parsing an element tree and returning a DOM fragment to be inserted in the
* document before any of the inner elements is referenced by JavaScript.
*
* This process is required instead of calling the createElement method directly
* because bindings get attached when:
*
* 1) the node gets a layout frame constructed, or
* 2) the node gets its JavaScript reflector created, if it's in the document,
*
* whichever happens first. The createElement method would return a JavaScript
* reflector, but the element wouldn't be in the document, so the node wouldn't
* get XBL attached. After that point, even if the node is inserted into a
* document, it won't get XBL attached until either the frame is constructed or
* the reflector is garbage collected and the element is touched again.
*
* @param str
* String with the XML representation of XUL elements.
*
* @return DocumentFragment containing the corresponding element tree, including
* element nodes but excluding any text node.
*/
static parseXULToFragment(str, entities = "") {
let doc = gXULDOMParser.parseFromString(`
${entities}
<box xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
${str}
</box>
`, "application/xml");
// The XUL/XBL parser is set to ignore all-whitespace nodes, whereas (X)HTML
// does not do this. Most XUL code assumes that the whitespace has been
// stripped out, so we simply remove all text nodes after using the parser.
let nodeIterator = doc.createNodeIterator(doc, NodeFilter.SHOW_TEXT);
let currentNode = nodeIterator.nextNode();
while (currentNode) {
currentNode.remove();
currentNode = nodeIterator.nextNode();
}
// We use a range here so that we don't access the inner DOM elements from
// JavaScript before they are imported and inserted into a document.
let range = doc.createRange();
range.selectNodeContents(doc.querySelector("box"));
return range.extractContents();
}
}
// Attach the base class to the window so other scripts can use it:
window.MozXULElement = MozXULElement;
for (let script of [
"chrome://global/content/elements/stringbundle.js",
"chrome://global/content/elements/general.js",
]) {
Services.scriptloader.loadSubScript(script, window);
}
customElements.setElementCreationCallback("printpreview-toolbar", type => {
Services.scriptloader.loadSubScript(
"chrome://global/content/printPreviewToolbar.js", window);
});
}