Clean up structure of markdown extension (#161148)

- Move things related to the client under `client`
- Remove extra abstractions that are no longer used
- Add MdLanguageClient type

extensions/markdown-language-features/src/client/workspace.ts

@@ -0,0 +1,80 @@
+/*---------------------------------------------------------------------------------------------
+ *  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 { ITextDocument } from '../types/textDocument';
+import { Disposable } from '../util/dispose';
+import { isMarkdownFile, looksLikeMarkdownPath } from '../util/file';
+import { InMemoryDocument } from './inMemoryDocument';
+import { ResourceMap } from '../util/resourceMap';
+
+/**
+ * Provides set of markdown files known to VS Code.
+ *
+ * This includes both opened text documents and markdown files in the workspace.
+ */
+export class VsCodeMdWorkspace extends Disposable {
+
+	private _watcher: vscode.FileSystemWatcher | undefined;
+
+	private readonly _documentCache = new ResourceMap<ITextDocument>();
+
+	private readonly utf8Decoder = new TextDecoder('utf-8');
+
+	constructor() {
+		super();
+
+		this._watcher = this._register(vscode.workspace.createFileSystemWatcher('**/*.md'));
+
+		this._register(this._watcher.onDidChange(async resource => {
+			this._documentCache.delete(resource);
+		}));
+
+		this._register(this._watcher.onDidDelete(resource => {
+			this._documentCache.delete(resource);
+		}));
+
+		this._register(vscode.workspace.onDidOpenTextDocument(e => {
+			this._documentCache.delete(e.uri);
+		}));
+
+		this._register(vscode.workspace.onDidCloseTextDocument(e => {
+			this._documentCache.delete(e.uri);
+		}));
+	}
+
+	private isRelevantMarkdownDocument(doc: vscode.TextDocument) {
+		return isMarkdownFile(doc) && doc.uri.scheme !== 'vscode-bulkeditpreview';
+	}
+
+	public async getOrLoadMarkdownDocument(resource: vscode.Uri): Promise<ITextDocument | undefined> {
+		const existing = this._documentCache.get(resource);
+		if (existing) {
+			return existing;
+		}
+
+		const matchingDocument = vscode.workspace.textDocuments.find((doc) => this.isRelevantMarkdownDocument(doc) && doc.uri.toString() === resource.toString());
+		if (matchingDocument) {
+			this._documentCache.set(resource, matchingDocument);
+			return matchingDocument;
+		}
+
+		if (!looksLikeMarkdownPath(resource)) {
+			return undefined;
+		}
+
+		try {
+			const bytes = await vscode.workspace.fs.readFile(resource);
+
+			// We assume that markdown is in UTF-8
+			const text = this.utf8Decoder.decode(bytes);
+			const doc = new InMemoryDocument(resource, text, 0);
+			this._documentCache.set(resource, doc);
+			return doc;
+		} catch {
+			return undefined;
+		}
+	}
+}