iframe.ts

/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
'use strict';

/**
 * Represents a window in a possible chain of iframes
 */
export interface IWindowChainElement {
	/**
	 * The window object for it
	 */
	window: Window;
	/**
	 * The iframe element inside the window.parent corresponding to window
	 */
	iframeElement: HTMLIFrameElement;
}

let hasDifferentOriginAncestorFlag: boolean = false;
let sameOriginWindowChainCache: IWindowChainElement[] = null;

function getParentWindowIfSameOrigin(w: Window): Window {
	if (!w.parent || w.parent === w) {
		return null;
	}

	// Cannot really tell if we have access to the parent window unless we try to access something in it
	try {
		let location = w.location;
		let parentLocation = w.parent.location;
		if (location.protocol !== parentLocation.protocol || location.hostname !== parentLocation.hostname || location.port !== parentLocation.port) {
			hasDifferentOriginAncestorFlag = true;
			return null;
		}
	} catch (e) {
		hasDifferentOriginAncestorFlag = true;
		return null;
	}

	return w.parent;
}

function findIframeElementInParentWindow(parentWindow: Window, childWindow: Window): HTMLIFrameElement {
	let parentWindowIframes = parentWindow.document.getElementsByTagName('iframe');
	let iframe: HTMLIFrameElement;
	for (let i = 0, len = parentWindowIframes.length; i < len; i++) {
		iframe = parentWindowIframes[i];
		if (iframe.contentWindow === childWindow) {
			return iframe;
		}
	}
	return null;
}

/**
 * Returns a chain of embedded windows with the same origin (which can be accessed programmatically).
 * Having a chain of length 1 might mean that the current execution environment is running outside of an iframe or inside an iframe embedded in a window with a different origin.
 * To distinguish if at one point the current execution environment is running inside a window with a different origin, see hasDifferentOriginAncestor()
 */
export function getSameOriginWindowChain(): IWindowChainElement[] {
	if (!sameOriginWindowChainCache) {
		sameOriginWindowChainCache = [];
		let w = window, parent: Window;
		do {
			parent = getParentWindowIfSameOrigin(w);
			if (parent) {
				sameOriginWindowChainCache.push({
					window: w,
					iframeElement: findIframeElementInParentWindow(parent, w)
				});
			} else {
				sameOriginWindowChainCache.push({
					window: w,
					iframeElement: null
				});
			}
			w = parent;
		} while (w);
	}
	return sameOriginWindowChainCache.slice(0);
}

/**
 * Returns true if the current execution environment is chained in a list of iframes which at one point ends in a window with a different origin.
 * Returns false if the current execution environment is not running inside an iframe or if the entire chain of iframes have the same origin.
 */
export function hasDifferentOriginAncestor(): boolean {
	if (!sameOriginWindowChainCache) {
		getSameOriginWindowChain();
	}
	return hasDifferentOriginAncestorFlag;
}

/**
 * Returns the position of `childWindow` relative to `ancestorWindow`
 */
export function getPositionOfChildWindowRelativeToAncestorWindow(childWindow: Window, ancestorWindow: any) {

	if (!ancestorWindow || childWindow === ancestorWindow) {
		return {
			top: 0,
			left: 0
		};
	}

	let top = 0, left = 0;

	let windowChain = getSameOriginWindowChain();

	for (let i = 0; i < windowChain.length; i++) {
		let windowChainEl = windowChain[i];

		if (windowChainEl.window === ancestorWindow) {
			break;
		}

		if (!windowChainEl.iframeElement) {
			break;
		}

		let boundingRect = windowChainEl.iframeElement.getBoundingClientRect();
		top += boundingRect.top;
		left += boundingRect.left;
	}

	return {
		top: top,
		left: left
	};
}