Initial work on md references provider

#146277

extensions/markdown-language-features/src/languageFeatures/references.ts

@@ -0,0 +1,53 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as vscode from 'vscode';
+import { MarkdownEngine } from '../markdownEngine';
+import { TableOfContents } from '../tableOfContents';
+import { Disposable } from '../util/dispose';
+import { MdWorkspaceContents } from '../workspaceContents';
+import { InternalLinkTarget, LinkData, MdLinkProvider } from './documentLinkProvider';
+import { MdWorkspaceCache } from './workspaceCache';
+
+
+export class MdReferencesProvider extends Disposable implements vscode.ReferenceProvider {
+
+	private readonly _linkCache: MdWorkspaceCache<Promise<LinkData[]>>;
+
+	public constructor(
+		linkProvider: MdLinkProvider,
+		workspaceContents: MdWorkspaceContents,
+		private readonly engine: MarkdownEngine,
+	) {
+		super();
+
+		this._linkCache = this._register(new MdWorkspaceCache(workspaceContents, doc => linkProvider.getInlineLinks(doc.getText(), doc)));
+	}
+
+	async provideReferences(document: vscode.TextDocument, position: vscode.Position, _context: vscode.ReferenceContext, token: vscode.CancellationToken): Promise<vscode.Location[] | undefined> {
+		const toc = await TableOfContents.create(this.engine, document);
+		if (token.isCancellationRequested) {
+			return undefined;
+		}
+
+		const header = toc.entries.find(entry => entry.line === position.line);
+		if (!header) {
+			return undefined;
+		}
+
+		const links = await Promise.all(await this._linkCache.getAll());
+		return links
+			.flat()
+			.filter(link => {
+				return link.target.kind === 'internal'
+					&& link.target.path.fsPath === document.uri.fsPath
+					&& link.target.fragment === header.slug.value;
+			})
+			.map(link => {
+				const target = link.target as InternalLinkTarget;
+				return new vscode.Location(target.fromResource, link.sourceRange);
+			});
+	}
+}