vscode/extensions/markdown-language-features/preview-src/index.ts
2023-06-23 02:40:39 +02:00

374 lines
11 KiB
TypeScript

/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License. See License.txt in the project root for license information.
*--------------------------------------------------------------------------------------------*/
import { ActiveLineMarker } from './activeLineMarker';
import { onceDocumentLoaded } from './events';
import { createPosterForVsCode } from './messaging';
import { getEditorLineNumberForPageOffset, scrollToRevealSourceLine, getLineElementForFragment } from './scroll-sync';
import { SettingsManager, getData } from './settings';
import throttle = require('lodash.throttle');
import morphdom from 'morphdom';
import type { ToWebviewMessage } from '../types/previewMessaging';
let scrollDisabledCount = 0;
const marker = new ActiveLineMarker();
const settings = new SettingsManager();
let documentVersion = 0;
let documentResource = settings.settings.source;
const vscode = acquireVsCodeApi();
const originalState = vscode.getState() ?? {} as any;
const state = {
...originalState,
...getData<any>('data-state')
};
if (typeof originalState.scrollProgress !== 'undefined' && originalState?.resource !== state.resource) {
state.scrollProgress = 0;
}
// Make sure to sync VS Code state here
vscode.setState(state);
const messaging = createPosterForVsCode(vscode, settings);
window.cspAlerter.setPoster(messaging);
window.styleLoadingMonitor.setPoster(messaging);
function doAfterImagesLoaded(cb: () => void) {
const imgElements = document.getElementsByTagName('img');
if (imgElements.length > 0) {
const ps = Array.from(imgElements, e => {
if (e.complete) {
return Promise.resolve();
} else {
return new Promise<void>((resolve) => {
e.addEventListener('load', () => resolve());
e.addEventListener('error', () => resolve());
});
}
});
Promise.all(ps).then(() => setTimeout(cb, 0));
} else {
setTimeout(cb, 0);
}
}
onceDocumentLoaded(() => {
const scrollProgress = state.scrollProgress;
addImageContexts();
if (typeof scrollProgress === 'number' && !settings.settings.fragment) {
doAfterImagesLoaded(() => {
scrollDisabledCount += 1;
// Always set scroll of at least 1 to prevent VS Code's webview code from auto scrolling us
const scrollToY = Math.max(1, scrollProgress * document.body.clientHeight);
window.scrollTo(0, scrollToY);
});
return;
}
if (settings.settings.scrollPreviewWithEditor) {
doAfterImagesLoaded(() => {
// Try to scroll to fragment if available
if (settings.settings.fragment) {
let fragment: string;
try {
fragment = encodeURIComponent(settings.settings.fragment);
} catch {
fragment = settings.settings.fragment;
}
state.fragment = undefined;
vscode.setState(state);
const element = getLineElementForFragment(fragment, documentVersion);
if (element) {
scrollDisabledCount += 1;
scrollToRevealSourceLine(element.line, documentVersion, settings);
}
} else {
if (!isNaN(settings.settings.line!)) {
scrollDisabledCount += 1;
scrollToRevealSourceLine(settings.settings.line!, documentVersion, settings);
}
}
});
}
if (typeof settings.settings.selectedLine === 'number') {
marker.onDidChangeTextEditorSelection(settings.settings.selectedLine, documentVersion);
}
});
const onUpdateView = (() => {
const doScroll = throttle((line: number) => {
scrollDisabledCount += 1;
doAfterImagesLoaded(() => scrollToRevealSourceLine(line, documentVersion, settings));
}, 50);
return (line: number) => {
if (!isNaN(line)) {
state.line = line;
doScroll(line);
}
};
})();
window.addEventListener('resize', () => {
scrollDisabledCount += 1;
updateScrollProgress();
}, true);
function addImageContexts() {
const images = document.getElementsByTagName('img');
let idNumber = 0;
for (const img of images) {
img.id = 'image-' + idNumber;
idNumber += 1;
img.setAttribute('data-vscode-context', JSON.stringify({ webviewSection: 'image', id: img.id, 'preventDefaultContextMenuItems': true, resource: documentResource }));
}
}
async function copyImage(image: HTMLImageElement, retries = 5) {
if (!document.hasFocus() && retries > 0) {
// copyImage is called at the same time as webview.reveal, which means this function is running whilst the webview is gaining focus.
// Since navigator.clipboard.write requires the document to be focused, we need to wait for focus.
// We cannot use a listener, as there is a high chance the focus is gained during the setup of the listener resulting in us missing it.
setTimeout(() => { copyImage(image, retries - 1); }, 20);
return;
}
try {
await navigator.clipboard.write([new ClipboardItem({
'image/png': new Promise((resolve) => {
const canvas = document.createElement('canvas');
if (canvas !== null) {
canvas.width = image.naturalWidth;
canvas.height = image.naturalHeight;
const context = canvas.getContext('2d');
context?.drawImage(image, 0, 0);
}
canvas.toBlob((blob) => {
if (blob) {
resolve(blob);
}
canvas.remove();
}, 'image/png');
})
})]);
} catch (e) {
console.error(e);
}
}
window.addEventListener('message', async event => {
const data = event.data as ToWebviewMessage.Type;
switch (data.type) {
case 'copyImage': {
const img = document.getElementById(data.id);
if (img instanceof HTMLImageElement) {
copyImage(img);
}
return;
}
case 'onDidChangeTextEditorSelection':
if (data.source === documentResource) {
marker.onDidChangeTextEditorSelection(data.line, documentVersion);
}
return;
case 'updateView':
if (data.source === documentResource) {
onUpdateView(data.line);
}
return;
case 'updateContent': {
const root = document.querySelector('.markdown-body')!;
const parser = new DOMParser();
const newContent = parser.parseFromString(data.content, 'text/html'); // CodeQL [SM03712] This renderers content from the workspace into the Markdown preview. Webviews (and the markdown preview) have many other security measures in place to make this safe
// Strip out meta http-equiv tags
for (const metaElement of Array.from(newContent.querySelectorAll('meta'))) {
if (metaElement.hasAttribute('http-equiv')) {
metaElement.remove();
}
}
if (data.source !== documentResource) {
root.replaceWith(newContent.querySelector('.markdown-body')!);
documentResource = data.source;
} else {
const skippedAttrs = [
'open', // for details
];
// Compare two elements but some elements
const areEqual = (a: Element, b: Element): boolean => {
if (a.isEqualNode(b)) {
return true;
}
if (a.tagName !== b.tagName || a.textContent !== b.textContent) {
return false;
}
const aAttrs = [...a.attributes].filter(attr => !skippedAttrs.includes(attr.name));
const bAttrs = [...b.attributes].filter(attr => !skippedAttrs.includes(attr.name));
if (aAttrs.length !== bAttrs.length) {
return false;
}
for (let i = 0; i < aAttrs.length; ++i) {
const aAttr = aAttrs[i];
const bAttr = bAttrs[i];
if (aAttr.name !== bAttr.name) {
return false;
}
if (aAttr.value !== bAttr.value && aAttr.name !== 'data-line') {
return false;
}
}
const aChildren = Array.from(a.children);
const bChildren = Array.from(b.children);
return aChildren.length === bChildren.length && aChildren.every((x, i) => areEqual(x, bChildren[i]));
};
const newRoot = newContent.querySelector('.markdown-body')!;
// Move styles to head
// This prevents an ugly flash of unstyled content
const styles = newRoot.querySelectorAll('link');
for (const style of styles) {
style.remove();
}
newRoot.prepend(...styles);
morphdom(root, newRoot, {
childrenOnly: true,
onBeforeElUpdated: (fromEl, toEl) => {
if (areEqual(fromEl, toEl)) {
// areEqual doesn't look at `data-line` so copy those over manually
const fromLines = fromEl.querySelectorAll('[data-line]');
const toLines = toEl.querySelectorAll('[data-line]');
if (fromLines.length !== toLines.length) {
console.log('unexpected line number change');
}
for (let i = 0; i < fromLines.length; ++i) {
const fromChild = fromLines[i];
const toChild = toLines[i];
if (toChild) {
fromChild.setAttribute('data-line', toChild.getAttribute('data-line')!);
}
}
return false;
}
if (fromEl.tagName === 'DETAILS' && toEl.tagName === 'DETAILS') {
if (fromEl.hasAttribute('open')) {
toEl.setAttribute('open', '');
}
}
return true;
}
});
}
++documentVersion;
window.dispatchEvent(new CustomEvent('vscode.markdown.updateContent'));
addImageContexts();
break;
}
}
}, false);
document.addEventListener('dblclick', event => {
if (!settings.settings.doubleClickToSwitchToEditor) {
return;
}
// Ignore clicks on links
for (let node = event.target as HTMLElement; node; node = node.parentNode as HTMLElement) {
if (node.tagName === 'A') {
return;
}
}
const offset = event.pageY;
const line = getEditorLineNumberForPageOffset(offset, documentVersion);
if (typeof line === 'number' && !isNaN(line)) {
messaging.postMessage('didClick', { line: Math.floor(line) });
}
});
const passThroughLinkSchemes = ['http:', 'https:', 'mailto:', 'vscode:', 'vscode-insiders:'];
document.addEventListener('click', event => {
if (!event) {
return;
}
let node: any = event.target;
while (node) {
if (node.tagName && node.tagName === 'A' && node.href) {
if (node.getAttribute('href').startsWith('#')) {
return;
}
let hrefText = node.getAttribute('data-href');
if (!hrefText) {
// Pass through known schemes
if (passThroughLinkSchemes.some(scheme => node.href.startsWith(scheme))) {
return;
}
hrefText = node.getAttribute('href');
}
// If original link doesn't look like a url, delegate back to VS Code to resolve
if (!/^[a-z\-]+:/i.test(hrefText)) {
messaging.postMessage('openLink', { href: hrefText });
event.preventDefault();
event.stopPropagation();
return;
}
return;
}
node = node.parentNode;
}
}, true);
window.addEventListener('scroll', throttle(() => {
updateScrollProgress();
if (scrollDisabledCount > 0) {
scrollDisabledCount -= 1;
} else {
const line = getEditorLineNumberForPageOffset(window.scrollY, documentVersion);
if (typeof line === 'number' && !isNaN(line)) {
messaging.postMessage('revealLine', { line });
}
}
}, 50));
function updateScrollProgress() {
state.scrollProgress = window.scrollY / document.body.clientHeight;
vscode.setState(state);
}