Revert "remove proposed Logger-api, #43275"

This reverts commit 1c72ab243c.

src/vs/workbench/api/node/extHostLogService.ts

@@ -4,6 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 'use strict';
 
+import * as vscode from 'vscode';
 import { join } from 'vs/base/common/paths';
 import { LogLevel } from 'vs/workbench/api/node/extHostTypes';
 import { ILogService, DelegatedLogService } from 'vs/platform/log/common/log';
@@ -13,6 +14,8 @@ import { ExtHostLogServiceShape } from 'vs/workbench/api/node/extHost.protocol';
 
 export class ExtHostLogService extends DelegatedLogService implements ILogService, ExtHostLogServiceShape {
 
+	private _loggers: Map<string, ExtHostLogger> = new Map();
+
 	constructor(
 		private _windowId: number,
 		logLevel: LogLevel,
@@ -25,7 +28,54 @@ export class ExtHostLogService extends DelegatedLogService implements ILogServic
 		this.setLevel(level);
 	}
 
+	getExtLogger(extensionID: string): ExtHostLogger {
+		let logger = this._loggers.get(extensionID);
+		if (!logger) {
+			logger = this.createLogger(extensionID);
+			this._loggers.set(extensionID, logger);
+		}
+		return logger;
+	}
+
 	getLogDirectory(extensionID: string): string {
 		return join(this._logsPath, `${extensionID}_${this._windowId}`);
 	}
+
+	private createLogger(extensionID: string): ExtHostLogger {
+		const logsDirPath = this.getLogDirectory(extensionID);
+		const logService = createSpdLogService(extensionID, this.getLevel(), logsDirPath);
+		this._register(this.onDidChangeLogLevel(level => logService.setLevel(level)));
+		return new ExtHostLogger(logService);
+	}
+}
+
+export class ExtHostLogger implements vscode.Logger {
+
+	constructor(
+		private readonly _logService: ILogService
+	) { }
+
+	trace(message: string, ...args: any[]): void {
+		return this._logService.trace(message, ...args);
+	}
+
+	debug(message: string, ...args: any[]): void {
+		return this._logService.debug(message, ...args);
+	}
+
+	info(message: string, ...args: any[]): void {
+		return this._logService.info(message, ...args);
+	}
+
+	warn(message: string, ...args: any[]): void {
+		return this._logService.warn(message, ...args);
+	}
+
+	error(message: string | Error, ...args: any[]): void {
+		return this._logService.error(message, ...args);
+	}
+
+	critical(message: string | Error, ...args: any[]): void {
+		return this._logService.critical(message, ...args);
+	}
 }