359 lines
11 KiB
TypeScript
359 lines
11 KiB
TypeScript
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/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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import { MarkdownIt, Token } from 'markdown-it';
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import * as path from 'path';
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import * as vscode from 'vscode';
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import { MarkdownContributionProvider as MarkdownContributionProvider } from './markdownExtensions';
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import { Slugifier } from './slugify';
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import { SkinnyTextDocument } from './tableOfContentsProvider';
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import { hash } from './util/hash';
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import { isOfScheme, MarkdownFileExtensions, Schemes } from './util/links';
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const UNICODE_NEWLINE_REGEX = /\u2028|\u2029/g;
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interface MarkdownItConfig {
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readonly breaks: boolean;
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readonly linkify: boolean;
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}
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class TokenCache {
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private cachedDocument?: {
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readonly uri: vscode.Uri;
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readonly version: number;
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readonly config: MarkdownItConfig;
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};
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private tokens?: Token[];
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public tryGetCached(document: SkinnyTextDocument, config: MarkdownItConfig): Token[] | undefined {
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if (this.cachedDocument
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&& this.cachedDocument.uri.toString() === document.uri.toString()
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&& this.cachedDocument.version === document.version
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&& this.cachedDocument.config.breaks === config.breaks
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&& this.cachedDocument.config.linkify === config.linkify
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) {
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return this.tokens;
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}
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return undefined;
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}
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public update(document: SkinnyTextDocument, config: MarkdownItConfig, tokens: Token[]) {
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this.cachedDocument = {
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uri: document.uri,
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version: document.version,
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config,
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};
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this.tokens = tokens;
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}
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public clean(): void {
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this.cachedDocument = undefined;
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this.tokens = undefined;
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}
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}
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export class MarkdownEngine {
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private md?: Promise<MarkdownIt>;
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private currentDocument?: vscode.Uri;
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private _slugCount = new Map<string, number>();
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private _tokenCache = new TokenCache();
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public constructor(
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private readonly contributionProvider: MarkdownContributionProvider,
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private readonly slugifier: Slugifier,
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) {
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contributionProvider.onContributionsChanged(() => {
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// Markdown plugin contributions may have changed
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this.md = undefined;
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});
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}
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private async getEngine(config: MarkdownItConfig): Promise<MarkdownIt> {
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if (!this.md) {
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this.md = import('markdown-it').then(async markdownIt => {
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let md: MarkdownIt = markdownIt(await getMarkdownOptions(() => md));
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for (const plugin of this.contributionProvider.contributions.markdownItPlugins.values()) {
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try {
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md = (await plugin)(md);
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} catch {
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// noop
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}
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}
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const frontMatterPlugin = require('markdown-it-front-matter');
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// Extract rules from front matter plugin and apply at a lower precedence
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let fontMatterRule: any;
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frontMatterPlugin({
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block: {
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ruler: {
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before: (_id: any, _id2: any, rule: any) => { fontMatterRule = rule; }
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}
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}
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}, () => { /* noop */ });
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md.block.ruler.before('fence', 'front_matter', fontMatterRule, {
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alt: ['paragraph', 'reference', 'blockquote', 'list']
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});
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for (const renderName of ['paragraph_open', 'heading_open', 'image', 'code_block', 'fence', 'blockquote_open', 'list_item_open']) {
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this.addLineNumberRenderer(md, renderName);
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}
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this.addImageStabilizer(md);
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this.addFencedRenderer(md);
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this.addLinkNormalizer(md);
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this.addLinkValidator(md);
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this.addNamedHeaders(md);
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this.addLinkRenderer(md);
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return md;
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});
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}
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const md = await this.md!;
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md.set(config);
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return md;
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}
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private tokenizeDocument(
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document: SkinnyTextDocument,
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config: MarkdownItConfig,
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engine: MarkdownIt
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): Token[] {
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const cached = this._tokenCache.tryGetCached(document, config);
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if (cached) {
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return cached;
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}
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this.currentDocument = document.uri;
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const tokens = this.tokenizeString(document.getText(), engine);
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this._tokenCache.update(document, config, tokens);
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return tokens;
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}
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private tokenizeString(text: string, engine: MarkdownIt) {
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this._slugCount = new Map<string, number>();
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return engine.parse(text.replace(UNICODE_NEWLINE_REGEX, ''), {});
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}
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public async render(input: SkinnyTextDocument | string): Promise<string> {
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const config = this.getConfig(typeof input === 'string' ? undefined : input.uri);
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const engine = await this.getEngine(config);
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const tokens = typeof input === 'string'
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? this.tokenizeString(input, engine)
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: this.tokenizeDocument(input, config, engine);
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return engine.renderer.render(tokens, {
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...(engine as any).options,
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...config
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}, {});
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}
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public async parse(document: SkinnyTextDocument): Promise<Token[]> {
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const config = this.getConfig(document.uri);
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const engine = await this.getEngine(config);
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return this.tokenizeDocument(document, config, engine);
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}
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public cleanCache(): void {
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this._tokenCache.clean();
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}
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private getConfig(resource?: vscode.Uri): MarkdownItConfig {
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const config = vscode.workspace.getConfiguration('markdown', resource);
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return {
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breaks: config.get<boolean>('preview.breaks', false),
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linkify: config.get<boolean>('preview.linkify', true)
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};
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}
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private addLineNumberRenderer(md: any, ruleName: string): void {
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const original = md.renderer.rules[ruleName];
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md.renderer.rules[ruleName] = (tokens: any, idx: number, options: any, env: any, self: any) => {
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const token = tokens[idx];
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if (token.map && token.map.length) {
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token.attrSet('data-line', token.map[0]);
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token.attrJoin('class', 'code-line');
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}
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if (original) {
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return original(tokens, idx, options, env, self);
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} else {
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return self.renderToken(tokens, idx, options, env, self);
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}
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};
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}
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private addImageStabilizer(md: any): void {
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const original = md.renderer.rules.image;
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md.renderer.rules.image = (tokens: any, idx: number, options: any, env: any, self: any) => {
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const token = tokens[idx];
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token.attrJoin('class', 'loading');
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const src = token.attrGet('src');
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if (src) {
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const imgHash = hash(src);
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token.attrSet('id', `image-hash-${imgHash}`);
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}
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if (original) {
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return original(tokens, idx, options, env, self);
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} else {
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return self.renderToken(tokens, idx, options, env, self);
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}
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};
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}
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private addFencedRenderer(md: any): void {
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const original = md.renderer.rules['fenced'];
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md.renderer.rules['fenced'] = (tokens: any, idx: number, options: any, env: any, self: any) => {
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const token = tokens[idx];
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if (token.map && token.map.length) {
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token.attrJoin('class', 'hljs');
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}
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return original(tokens, idx, options, env, self);
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};
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}
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private addLinkNormalizer(md: any): void {
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const normalizeLink = md.normalizeLink;
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md.normalizeLink = (link: string) => {
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try {
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// Normalize VS Code schemes to target the current version
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if (isOfScheme(Schemes.vscode, link) || isOfScheme(Schemes['vscode-insiders'], link)) {
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return normalizeLink(vscode.Uri.parse(link).with({ scheme: vscode.env.uriScheme }).toString());
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}
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// If original link doesn't look like a url with a scheme, assume it must be a link to a file in workspace
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if (!/^[a-z\-]+:/i.test(link)) {
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// Use a fake scheme for parsing
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let uri = vscode.Uri.parse('markdown-link:' + link);
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// Relative paths should be resolved correctly inside the preview but we need to
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// handle absolute paths specially (for images) to resolve them relative to the workspace root
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if (uri.path[0] === '/') {
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const root = vscode.workspace.getWorkspaceFolder(this.currentDocument!);
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if (root) {
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const fileUri = vscode.Uri.joinPath(root.uri, uri.fsPath);
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uri = fileUri.with({
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scheme: uri.scheme,
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fragment: uri.fragment,
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query: uri.query,
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});
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}
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}
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const extname = path.extname(uri.fsPath);
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if (uri.fragment && (extname === '' || MarkdownFileExtensions.includes(extname))) {
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uri = uri.with({
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fragment: this.slugifier.fromHeading(uri.fragment).value
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});
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}
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return normalizeLink(uri.toString(true).replace(/^markdown-link:/, ''));
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}
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} catch (e) {
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// noop
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}
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return normalizeLink(link);
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};
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}
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private addLinkValidator(md: any): void {
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const validateLink = md.validateLink;
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md.validateLink = (link: string) => {
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// support file:// links
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return validateLink(link)
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|| isOfScheme(Schemes.file, link)
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|| isOfScheme(Schemes.vscode, link)
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|| isOfScheme(Schemes['vscode-insiders'], link)
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|| /^data:image\/.*?;/.test(link);
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};
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}
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private addNamedHeaders(md: any): void {
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const original = md.renderer.rules.heading_open;
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md.renderer.rules.heading_open = (tokens: any, idx: number, options: any, env: any, self: any) => {
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const title = tokens[idx + 1].children.reduce((acc: string, t: any) => acc + t.content, '');
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let slug = this.slugifier.fromHeading(title);
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if (this._slugCount.has(slug.value)) {
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const count = this._slugCount.get(slug.value)!;
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this._slugCount.set(slug.value, count + 1);
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slug = this.slugifier.fromHeading(slug.value + '-' + (count + 1));
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} else {
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this._slugCount.set(slug.value, 0);
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}
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tokens[idx].attrs = tokens[idx].attrs || [];
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tokens[idx].attrs.push(['id', slug.value]);
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if (original) {
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return original(tokens, idx, options, env, self);
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} else {
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return self.renderToken(tokens, idx, options, env, self);
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}
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};
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}
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private addLinkRenderer(md: any): void {
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const old_render = md.renderer.rules.link_open || ((tokens: any, idx: number, options: any, _env: any, self: any) => {
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return self.renderToken(tokens, idx, options);
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});
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md.renderer.rules.link_open = (tokens: any, idx: number, options: any, env: any, self: any) => {
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const token = tokens[idx];
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const hrefIndex = token.attrIndex('href');
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if (hrefIndex >= 0) {
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const href = token.attrs[hrefIndex][1];
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token.attrPush(['data-href', href]);
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}
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return old_render(tokens, idx, options, env, self);
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};
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}
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}
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async function getMarkdownOptions(md: () => MarkdownIt) {
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const hljs = await import('highlight.js');
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return {
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html: true,
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highlight: (str: string, lang?: string) => {
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lang = normalizeHighlightLang(lang);
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if (lang && hljs.getLanguage(lang)) {
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try {
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return `<div>${hljs.highlight(lang, str, true).value}</div>`;
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}
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catch (error) { }
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}
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return `<code><div>${md().utils.escapeHtml(str)}</div></code>`;
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}
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};
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}
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function normalizeHighlightLang(lang: string | undefined) {
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switch (lang && lang.toLowerCase()) {
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case 'tsx':
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case 'typescriptreact':
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// Workaround for highlight not supporting tsx: https://github.com/isagalaev/highlight.js/issues/1155
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return 'jsx';
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case 'json5':
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case 'jsonc':
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return 'json';
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case 'c#':
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case 'csharp':
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return 'cs';
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default:
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return lang;
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}
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}
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