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+/*
+ * 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/>.
+ */
+
+/* global
+ * api
+ */
+
+/**
+ * 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;
+ }
+ api.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 ${timeout}ms`));
+ };
+ const resetTimeout = () => {
+ if (timer !== null) { clearTimeout(timer); }
+ timer = setTimeout(onTimeout, timeout);
+ };
+
+ // Start
+ api.crossFrame.registerHandlers([[responseMessageId, {async: false, handler: onMessage}]]);
+ resetTimeout();
+ const frameId = this._frameId;
+ this._requestFrameInfo(targetWindow, frameId, frameId, uniqueId, nonce);
+ });
+ }
+
+ _onWindowMessage(event) {
+ const {source} = event;
+ if (source === window || source.parent !== window) { return; }
+
+ const {data} = event;
+ if (
+ typeof data === 'object' &&
+ data !== null &&
+ data.action === this._requestMessageId
+ ) {
+ this._onRequestFrameInfo(data.params, source);
+ }
+ }
+
+ async _onRequestFrameInfo(params, source) {
+ try {
+ let {originFrameId, childFrameId, uniqueId, nonce} = params;
+ if (
+ !this._isNonNegativeInteger(originFrameId) ||
+ typeof uniqueId !== 'string' ||
+ typeof nonce !== 'string'
+ ) {
+ return;
+ }
+
+ const frameId = this._frameId;
+ const {parent} = window;
+ const more = (window !== parent);
+ const responseParams = {frameId, nonce, more};
+ const responseMessageId = `${this._responseMessageIdBase}${uniqueId}`;
+
+ try {
+ const response = await api.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;
+ }
+}