Refactor document link opening

- Extract out of command
- Try to preserve uri instead of converting to path
- Better handle case with absolute file path when there is no workspace

extensions/markdown-language-features/src/util/openDocumentLink.ts

@@ -0,0 +1,161 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as path from 'path';
+import * as vscode from 'vscode';
+import { MarkdownEngine } from '../markdownEngine';
+import { TableOfContentsProvider } from '../tableOfContentsProvider';
+import { isMarkdownFile } from '../util/file';
+import { extname } from '../util/path';
+
+export interface OpenDocumentLinkArgs {
+	readonly parts: vscode.Uri;
+	readonly fragment: string;
+	readonly fromResource: vscode.Uri;
+}
+
+enum OpenMarkdownLinks {
+	beside = 'beside',
+	currentGroup = 'currentGroup',
+}
+
+export function resolveDocumentLink(href: string, markdownFile: vscode.Uri): vscode.Uri {
+	let [hrefPath, fragment] = href.split('#').map(c => decodeURIComponent(c));
+
+	if (hrefPath[0] === '/') {
+		// Absolute path. Try to resolve relative to the workspace
+		const workspace = vscode.workspace.getWorkspaceFolder(markdownFile);
+		if (workspace) {
+			return vscode.Uri.joinPath(workspace.uri, hrefPath.slice(1)).with({ fragment });
+		}
+	}
+
+	// Relative path. Resolve relative to the md file
+	const dirnameUri = markdownFile.with({ path: path.dirname(markdownFile.path) });
+	return vscode.Uri.joinPath(dirnameUri, hrefPath).with({ fragment });
+}
+
+export async function openDocumentLink(engine: MarkdownEngine, targetResource: vscode.Uri, fromResource: vscode.Uri): Promise<void> {
+	const column = getViewColumn(fromResource);
+
+	if (await tryNavigateToFragmentInActiveEditor(engine, targetResource)) {
+		return;
+	}
+
+	let targetResourceStat: vscode.FileStat | undefined;
+	try {
+		targetResourceStat = await vscode.workspace.fs.stat(targetResource);
+	} catch {
+		// noop
+	}
+
+	if (typeof targetResourceStat === 'undefined') {
+		// We don't think the file exists. If it doesn't already have an extension, try tacking on a `.md` and using that instead
+		if (extname(targetResource.path) === '') {
+			const dotMdResource = targetResource.with({ path: targetResource.path + '.md' });
+			try {
+				const stat = await vscode.workspace.fs.stat(dotMdResource);
+				if (stat.type === vscode.FileType.File) {
+					await tryOpenMdFile(engine, dotMdResource, column);
+					return;
+				}
+			} catch {
+				// noop
+			}
+		}
+	} else if (targetResourceStat.type === vscode.FileType.Directory) {
+		return vscode.commands.executeCommand('revealInExplorer', targetResource);
+	}
+
+	await tryOpenMdFile(engine, targetResource, column);
+}
+
+async function tryOpenMdFile(engine: MarkdownEngine, resource: vscode.Uri, column: vscode.ViewColumn): Promise<boolean> {
+	await vscode.commands.executeCommand('vscode.open', resource, column);
+	return tryNavigateToFragmentInActiveEditor(engine, resource);
+}
+
+async function tryNavigateToFragmentInActiveEditor(engine: MarkdownEngine, resource: vscode.Uri): Promise<boolean> {
+	const activeEditor = vscode.window.activeTextEditor;
+	if (activeEditor?.document.uri.fsPath === resource.fsPath) {
+		if (isMarkdownFile(activeEditor.document)) {
+			if (await tryRevealLineUsingTocFragment(engine, activeEditor, resource.fragment)) {
+				return true;
+			}
+		}
+		tryRevealLineUsingLineFragment(activeEditor, resource.fragment);
+		return true;
+	}
+	return false;
+}
+
+function getViewColumn(resource: vscode.Uri): vscode.ViewColumn {
+	const config = vscode.workspace.getConfiguration('markdown', resource);
+	const openLinks = config.get<OpenMarkdownLinks>('links.openLocation', OpenMarkdownLinks.currentGroup);
+	switch (openLinks) {
+		case OpenMarkdownLinks.beside:
+			return vscode.ViewColumn.Beside;
+		case OpenMarkdownLinks.currentGroup:
+		default:
+			return vscode.ViewColumn.Active;
+	}
+}
+
+async function tryRevealLineUsingTocFragment(engine: MarkdownEngine, editor: vscode.TextEditor, fragment: string): Promise<boolean> {
+	const toc = new TableOfContentsProvider(engine, editor.document);
+	const entry = await toc.lookup(fragment);
+	if (entry) {
+		const lineStart = new vscode.Range(entry.line, 0, entry.line, 0);
+		editor.selection = new vscode.Selection(lineStart.start, lineStart.end);
+		editor.revealRange(lineStart, vscode.TextEditorRevealType.AtTop);
+		return true;
+	}
+	return false;
+}
+
+function tryRevealLineUsingLineFragment(editor: vscode.TextEditor, fragment: string): boolean {
+	const lineNumberFragment = fragment.match(/^L(\d+)$/i);
+	if (lineNumberFragment) {
+		const line = +lineNumberFragment[1] - 1;
+		if (!isNaN(line)) {
+			const lineStart = new vscode.Range(line, 0, line, 0);
+			editor.selection = new vscode.Selection(lineStart.start, lineStart.end);
+			editor.revealRange(lineStart, vscode.TextEditorRevealType.AtTop);
+			return true;
+		}
+	}
+	return false;
+}
+
+export async function resolveLinkToMarkdownFile(resource: vscode.Uri): Promise<vscode.Uri | undefined> {
+	try {
+		const standardLink = await tryResolveLinkToMarkdownFile(resource);
+		if (standardLink) {
+			return standardLink;
+		}
+	} catch {
+		// Noop
+	}
+
+	// If no extension, try with `.md` extension
+	if (extname(resource.path) === '') {
+		return tryResolveLinkToMarkdownFile(resource.with({ path: resource.path + '.md' }));
+	}
+
+	return undefined;
+}
+
+async function tryResolveLinkToMarkdownFile(resource: vscode.Uri): Promise<vscode.Uri | undefined> {
+	let document: vscode.TextDocument;
+	try {
+		document = await vscode.workspace.openTextDocument(resource);
+	} catch {
+		return undefined;
+	}
+	if (isMarkdownFile(document)) {
+		return document.uri;
+	}
+	return undefined;
+}