SingleFile/lib/hooks/hooks-web.js

/*
 * Copyright 2010-2019 Gildas Lormeau
 * contact : gildas.lormeau <at> gmail.com
 * 
 * This file is part of SingleFile.
 *
 *   The code in this file is free software: you can redistribute it and/or 
 *   modify it under the terms of the GNU Affero General Public License 
 *   (GNU AGPL) as published by the Free Software Foundation, either version 3
 *   of the License, or (at your option) any later version.
 * 
 *   The code in this file 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 Affero 
 *   General Public License for more details.
 *
 *   As additional permission under GNU AGPL version 3 section 7, you may 
 *   distribute UNMODIFIED VERSIONS OF THIS file without the copy of the GNU 
 *   AGPL normally required by section 4, provided you include this license 
 *   notice and a URL through which recipients can access the Corresponding 
 *   Source.
 */

/* global window, addEventListener, dispatchEvent, CustomEvent, document, screen, Element, UIEvent */

this.hooksFrame = this.hooksFrame || (() => {

	const LOAD_DEFERRED_IMAGES_START_EVENT = "single-file-load-deferred-images-start";
	const LOAD_DEFERRED_IMAGES_END_EVENT = "single-file-load-deferred-images-end";
	const LOAD_IMAGE_EVENT = "single-file-load-image";
	const IMAGE_LOADED_EVENT = "single-file-image-loaded";

	addEventListener(LOAD_DEFERRED_IMAGES_START_EVENT, () => {
		const clientHeight = document.documentElement.clientHeight;
		const clientWidth = document.documentElement.clientWidth;
		const scrollHeight = Math.max(document.documentElement.scrollHeight - (clientHeight * .5), clientHeight);
		const scrollWidth = Math.max(document.documentElement.scrollWidth - (clientWidth * .5), clientWidth);
		document.documentElement.__defineGetter__("clientHeight", () => scrollHeight);
		document.documentElement.__defineGetter__("clientWidth", () => scrollWidth);
		screen.__defineGetter__("height", () => scrollHeight);
		screen.__defineGetter__("width", () => scrollWidth);
		try {
			document.__defineGetter__("cookie", () => { throw new Error("document.cookie temporary blocked by SingleFile"); });
		} catch (error) {
			// ignored
		}
		if (!window._singleFile_getBoundingClientRect) {
			window._singleFile_getBoundingClientRect = Element.prototype.getBoundingClientRect;
			Element.prototype.getBoundingClientRect = function () {
				const boundingRect = window._singleFile_getBoundingClientRect.call(this);
				if (this == document.documentElement) {
					boundingRect.__defineGetter__("height", () => scrollHeight);
					boundingRect.__defineGetter__("bottom", () => scrollHeight + boundingRect.top);
					boundingRect.__defineGetter__("width", () => scrollWidth);
					boundingRect.__defineGetter__("right", () => scrollWidth + boundingRect.left);
				}
				return boundingRect;
			};
			window._singleFile_innerHeight = window.innerHeight;
			window._singleFile_innerWidth = window.innerWidth;
			window.__defineGetter__("innerHeight", () => scrollHeight);
			window.__defineGetter__("innerWidth", () => scrollWidth);
		}
		if (!window._singleFile_localStorage) {
			window._singleFile_localStorage = window.localStorage;
			window.__defineGetter__("localStorage", () => { throw new Error("localStorage temporary blocked by SingleFile"); });
		}
		if (!window._singleFile_indexedDB) {
			window._singleFile_indexedDB = window.indexedDB;
			window.__defineGetter__("indexedDB", () => { throw new Error("indexedDB temporary blocked by SingleFile"); });
		}
		if (!window._singleFileImage) {
			const Image = window.Image;
			window._singleFileImage = window.Image;
			window.__defineGetter__("Image", function () {
				return function () {
					const image = new Image(...arguments);
					const result = new Image(...arguments);
					result.__defineSetter__("src", function (value) {
						image.src = value;
						dispatchEvent(new CustomEvent(LOAD_IMAGE_EVENT, { detail: image.src }));
					});
					result.__defineGetter__("src", function () {
						return image.src;
					});
					result.__defineSetter__("srcset", function (value) {
						dispatchEvent(new CustomEvent(LOAD_IMAGE_EVENT));
						image.srcset = value;
					});
					result.__defineGetter__("srcset", function () {
						return image.srcset;
					});
					image.onload = image.onloadend = image.onerror = event => {
						dispatchEvent(new CustomEvent(IMAGE_LOADED_EVENT, { detail: image.src }));
						result.dispatchEvent(new UIEvent(event.type, event));
					};
					return result;
				};
			});
		}
		const zoomFactorX = (clientHeight + window.scrollY) / scrollHeight;
		const zoomFactorY = (clientWidth + window.scrollX) / scrollWidth;
		const zoomFactor = Math.min(zoomFactorX, zoomFactorY);
		if (zoomFactor < 1) {
			const transform = document.documentElement.style.getPropertyValue("transform");
			const transformPriority = document.documentElement.style.getPropertyPriority("transform");
			const transformOrigin = document.documentElement.style.getPropertyValue("transform-origin");
			const transformOriginPriority = document.documentElement.style.getPropertyPriority("transform-origin");
			document.documentElement.style.setProperty("transform-origin", (zoomFactorX < 1 ? "50%" : "0") + " " + (zoomFactorY < 1 ? "50%" : "0") + " 0", "important");
			document.documentElement.style.setProperty("transform", "scale3d(" + zoomFactor + ", " + zoomFactor + ", 1)", "important");
			dispatchEvent(new UIEvent("resize"));
			dispatchEvent(new UIEvent("scroll"));
			document.documentElement.style.setProperty("transform", transform, transformPriority);
			document.documentElement.style.setProperty("transform-origin", transformOrigin, transformOriginPriority);
		}
		dispatchEvent(new UIEvent("resize"));
		dispatchEvent(new UIEvent("scroll"));
	});

	addEventListener(LOAD_DEFERRED_IMAGES_END_EVENT, () => {
		delete document.documentElement.clientHeight;
		delete document.documentElement.clientWidth;
		delete screen.height;
		delete screen.width;
		delete document.cookie;
		if (window._singleFile_getBoundingClientRect) {
			Element.prototype.getBoundingClientRect = window._singleFile_getBoundingClientRect;
			window.innerHeight = window._singleFile_innerHeight;
			window.innerWidth = window._singleFile_innerWidth;
			delete window._singleFile_getBoundingClientRect;
			delete window._singleFile_innerHeight;
			delete window._singleFile_innerWidth;
		}
		if (window._singleFile_localStorage) {
			delete window.localStorage;
			window.localStorage = window._singleFile_localStorage;
			delete window._singleFile_localStorage;
		}
		if (!window._singleFile_indexedDB) {
			delete window.indexedDB;
			window.indexedDB = window._singleFile_indexedDB;
			delete window._singleFile_indexedDB;
		}
		if (window._singleFileImage) {
			delete window.Image;
			window.Image = window._singleFileImage;
			delete window._singleFileImage;
		}
		dispatchEvent(new UIEvent("resize"));
		dispatchEvent(new UIEvent("scroll"));
	});

})();