/** @internal */

export interface PerfLogger {

logEvent(msg: string): void;

logErrEvent(msg: string): void;

logPerfEvent(msg: string): void;

logInfoEvent(msg: string): void;

logStartCommand(command: string, msg: string): void;

logStopCommand(command: string, msg: string): void;

logStartUpdateProgram(msg: string): void;

logStopUpdateProgram(msg: string): void;

logStartUpdateGraph(): void;

logStopUpdateGraph(): void;

logStartResolveModule(name: string): void;

logStopResolveModule(success: string): void;

logStartParseSourceFile(filename: string): void;

logStopParseSourceFile(): void;

logStartReadFile(filename: string): void;

logStopReadFile(): void;

logStartBindFile(filename: string): void;

logStopBindFile(): void;

logStartScheduledOperation(operationId: string): void;

logStopScheduledOperation(): void;

}

// Load optional module to enable Event Tracing for Windows

// See https://github.com/microsoft/typescript-etw for more information

let etwModule: typeof import("@microsoft/typescript-etw") | undefined;

try {

const etwModulePath = process.env.TS_ETW_MODULE_PATH ?? "./node_modules/@microsoft/typescript-etw";

// require() will throw an exception if the module is not found

// It may also return undefined if not installed properly

etwModule = require(etwModulePath);

}

catch (e) {

etwModule = undefined;

}

/**

* Performance logger that will generate ETW events if possible - check for `logEvent` member, as `etwModule` will be `{}` when browserified

*

* @internal

*/

export const perfLogger: PerfLogger | undefined = etwModule?.logEvent ? etwModule : undefined;