yomichan/ext/js/comm/frame-ancestry-handler.js
toasted-nutbread 286534e648
Move api to yomichan object (#1392)
* Move cross frame API from API to Yomichan

* Add API instance to Yomichan

* Move api global to yomichan.api

* Pass yomichan to API

* Remove IIFE
2021-02-14 15:53:35 -05:00

266 lines
8.9 KiB
JavaScript

/*
* Copyright (C) 2021 Yomichan Authors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/**
* This class is used to return the ancestor frame IDs for the current frame.
* This is a workaround to using the `webNavigation.getAllFrames` API, which
* would require an additional permission that is otherwise unnecessary.
* It is also used to track the correlation between child frame elements and their IDs.
*/
class FrameAncestryHandler {
/**
* Creates a new instance.
* @param frameId The frame ID of the current frame the instance is instantiated in.
*/
constructor(frameId) {
this._frameId = frameId;
this._isPrepared = false;
this._requestMessageId = 'FrameAncestryHandler.requestFrameInfo';
this._responseMessageIdBase = `${this._requestMessageId}.response.`;
this._getFrameAncestryInfoPromise = null;
this._childFrameMap = new Map();
}
/**
* Gets the frame ID that the instance is instantiated in.
*/
get frameId() {
return this._frameId;
}
/**
* Initializes event event listening.
*/
prepare() {
if (this._isPrepared) { return; }
window.addEventListener('message', this._onWindowMessage.bind(this), false);
this._isPrepared = true;
}
/**
* Returns whether or not this frame is the root frame in the tab.
* @returns `true` if it is the root, otherwise `false`.
*/
isRootFrame() {
return (window === window.parent);
}
/**
* Gets the frame ancestry information for the current frame. If the frame is the
* root frame, an empty array is returned. Otherwise, an array of frame IDs is returned,
* starting from the nearest ancestor.
* @param timeout The maximum time to wait to receive a response to frame information requests.
* @returns An array of frame IDs corresponding to the ancestors of the current frame.
*/
async getFrameAncestryInfo() {
if (this._getFrameAncestryInfoPromise === null) {
this._getFrameAncestryInfoPromise = this._getFrameAncestryInfo(5000);
}
return await this._getFrameAncestryInfoPromise;
}
/**
* Gets the frame element of a child frame given a frame ID.
* For this function to work, the `getFrameAncestryInfo` function needs to have
* been invoked previously.
* @param frameId The frame ID of the child frame to get.
* @returns The element corresponding to the frame with ID `frameId`, otherwise `null`.
*/
getChildFrameElement(frameId) {
const frameInfo = this._childFrameMap.get(frameId);
if (typeof frameInfo === 'undefined') { return null; }
let {frameElement} = frameInfo;
if (typeof frameElement === 'undefined') {
frameElement = this._findFrameElementWithContentWindow(frameInfo.window);
frameInfo.frameElement = frameElement;
}
return frameElement;
}
// Private
_getFrameAncestryInfo(timeout=5000) {
return new Promise((resolve, reject) => {
const targetWindow = window.parent;
if (window === targetWindow) {
resolve([]);
return;
}
const uniqueId = generateId(16);
let nonce = generateId(16);
const responseMessageId = `${this._responseMessageIdBase}${uniqueId}`;
const results = [];
let timer = null;
const cleanup = () => {
if (timer !== null) {
clearTimeout(timer);
timer = null;
}
yomichan.crossFrame.unregisterHandler(responseMessageId);
};
const onMessage = (params) => {
if (params.nonce !== nonce) { return null; }
// Add result
const {frameId, more} = params;
results.push(frameId);
nonce = generateId(16);
if (!more) {
// Cleanup
cleanup();
// Finish
resolve(results);
}
return {nonce};
};
const onTimeout = () => {
timer = null;
cleanup();
reject(new Error(`Request for parent frame ID timed out after ${timeout}ms`));
};
const resetTimeout = () => {
if (timer !== null) { clearTimeout(timer); }
timer = setTimeout(onTimeout, timeout);
};
// Start
yomichan.crossFrame.registerHandlers([[responseMessageId, {async: false, handler: onMessage}]]);
resetTimeout();
const frameId = this._frameId;
this._requestFrameInfo(targetWindow, frameId, frameId, uniqueId, nonce);
});
}
_onWindowMessage(event) {
const {source} = event;
if (source === window || source.parent !== window) { return; }
const {data} = event;
if (
typeof data === 'object' &&
data !== null &&
data.action === this._requestMessageId
) {
this._onRequestFrameInfo(data.params, source);
}
}
async _onRequestFrameInfo(params, source) {
try {
let {originFrameId, childFrameId, uniqueId, nonce} = params;
if (
!this._isNonNegativeInteger(originFrameId) ||
typeof uniqueId !== 'string' ||
typeof nonce !== 'string'
) {
return;
}
const frameId = this._frameId;
const {parent} = window;
const more = (window !== parent);
const responseParams = {frameId, nonce, more};
const responseMessageId = `${this._responseMessageIdBase}${uniqueId}`;
try {
const response = await yomichan.crossFrame.invoke(originFrameId, responseMessageId, responseParams);
if (response === null) { return; }
nonce = response.nonce;
} catch (e) {
return;
}
if (!this._childFrameMap.has(childFrameId)) {
this._childFrameMap.set(childFrameId, {window: source, frameElement: void 0});
}
if (more) {
this._requestFrameInfo(parent, originFrameId, frameId, uniqueId, nonce);
}
} catch (e) {
// NOP
}
}
_requestFrameInfo(targetWindow, originFrameId, childFrameId, uniqueId, nonce) {
targetWindow.postMessage({
action: this._requestMessageId,
params: {originFrameId, childFrameId, uniqueId, nonce}
}, '*');
}
_isNonNegativeInteger(value) {
return (
typeof value === 'number' &&
Number.isFinite(value) &&
value >= 0 &&
Math.floor(value) === value
);
}
_findFrameElementWithContentWindow(contentWindow) {
// Check frameElement, for non-null same-origin frames
try {
const {frameElement} = contentWindow;
if (frameElement !== null) { return frameElement; }
} catch (e) {
// NOP
}
// Check frames
const frameTypes = ['iframe', 'frame', 'embed'];
for (const frameType of frameTypes) {
for (const frame of document.getElementsByTagName(frameType)) {
if (frame.contentWindow === contentWindow) {
return frame;
}
}
}
// Check for shadow roots
const rootElements = [document.documentElement];
while (rootElements.length > 0) {
const rootElement = rootElements.shift();
const walker = document.createTreeWalker(rootElement, NodeFilter.SHOW_ELEMENT);
while (walker.nextNode()) {
const element = walker.currentNode;
if (element.contentWindow === contentWindow) {
return element;
}
const shadowRoot = (
element.shadowRoot ||
element.openOrClosedShadowRoot // Available to Firefox 63+ for WebExtensions
);
if (shadowRoot) {
rootElements.push(shadowRoot);
}
}
}
// Not found
return null;
}
}