Move all impl to scrollable/

src/browser/scrollable/iframe.ts

@@ -0,0 +1,135 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+/**
+ * Represents a window in a possible chain of iframes
+ */
+interface IWindowChainElement {
+	/**
+	 * The window object for it
+	 */
+	readonly window: WeakRef<Window>;
+	/**
+	 * The iframe element inside the window.parent corresponding to window
+	 */
+	readonly iframeElement: Element | null;
+}
+
+const sameOriginWindowChainCache = new WeakMap<Window, IWindowChainElement[] | null>();
+
+function getParentWindowIfSameOrigin(w: Window): Window | null {
+	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 {
+		const location = w.location;
+		const parentLocation = w.parent.location;
+		if (location.origin !== 'null' && parentLocation.origin !== 'null' && location.origin !== parentLocation.origin) {
+			return null;
+		}
+	} catch (e) {
+		return null;
+	}
+
+	return w.parent;
+}
+
+export class IframeUtils {
+
+	/**
+	 * 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.
+	 */
+	private static getSameOriginWindowChain(targetWindow: Window): IWindowChainElement[] {
+		let windowChainCache = sameOriginWindowChainCache.get(targetWindow);
+		if (!windowChainCache) {
+			windowChainCache = [];
+			sameOriginWindowChainCache.set(targetWindow, windowChainCache);
+			let w: Window | null = targetWindow;
+			let parent: Window | null;
+			do {
+				parent = getParentWindowIfSameOrigin(w);
+				if (parent) {
+					windowChainCache.push({
+						window: new WeakRef(w),
+						iframeElement: w.frameElement || null
+					});
+				} else {
+					windowChainCache.push({
+						window: new WeakRef(w),
+						iframeElement: null
+					});
+				}
+				w = parent;
+			} while (w);
+		}
+		return windowChainCache.slice(0);
+	}
+
+	/**
+	 * Returns the position of `childWindow` relative to `ancestorWindow`
+	 */
+	public static getPositionOfChildWindowRelativeToAncestorWindow(childWindow: Window, ancestorWindow: Window | null) {
+
+		if (!ancestorWindow || childWindow === ancestorWindow) {
+			return {
+				top: 0,
+				left: 0
+			};
+		}
+
+		let top = 0, left = 0;
+
+		const windowChain = this.getSameOriginWindowChain(childWindow);
+
+		for (const windowChainEl of windowChain) {
+			const windowInChain = windowChainEl.window.deref();
+			top += windowInChain?.scrollY ?? 0;
+			left += windowInChain?.scrollX ?? 0;
+
+			if (windowInChain === ancestorWindow) {
+				break;
+			}
+
+			if (!windowChainEl.iframeElement) {
+				break;
+			}
+
+			const boundingRect = windowChainEl.iframeElement.getBoundingClientRect();
+			top += boundingRect.top;
+			left += boundingRect.left;
+		}
+
+		return {
+			top: top,
+			left: left
+		};
+	}
+}
+
+/**
+ * Returns a sha-256 composed of `parentOrigin` and `salt` converted to base 32
+ */
+export async function parentOriginHash(parentOrigin: string, salt: string): Promise<string> {
+	// This same code is also inlined at `src/vs/workbench/services/extensions/worker/webWorkerExtensionHostIframe.html`
+	if (!crypto.subtle) {
+		throw new Error(`'crypto.subtle' is not available so webviews will not work. This is likely because the editor is not running in a secure context (https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts).`);
+	}
+
+	const strData = JSON.stringify({ parentOrigin, salt });
+	const encoder = new TextEncoder();
+	const arrData = encoder.encode(strData);
+	const hash = await crypto.subtle.digest('sha-256', arrData);
+	return sha256AsBase32(hash);
+}
+
+function sha256AsBase32(bytes: ArrayBuffer): string {
+	const array = Array.from(new Uint8Array(bytes));
+	const hexArray = array.map(b => b.toString(16).padStart(2, '0')).join('');
+	// sha256 has 256 bits, so we need at most ceil(lg(2^256-1)/lg(32)) = 52 chars to represent it in base 32
+	return BigInt(`0x${hexArray}`).toString(32).padStart(52, '0');
+}