goDebug.ts

/*---------------------------------------------------------
 * 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 os from 'os';
import * as fs from 'fs';
import * as util from 'util';
import { DebugProtocol } from 'vscode-debugprotocol';
import { DebugSession, InitializedEvent, TerminatedEvent, ThreadEvent, StoppedEvent, OutputEvent, Thread, StackFrame, Scope, Source, Handles, LoggingDebugSession, Logger, logger, Breakpoint } from 'vscode-debugadapter';
import { existsSync, lstatSync } from 'fs';
import { basename, dirname, extname } from 'path';
import { spawn, ChildProcess, execSync, spawnSync, execFile } from 'child_process';
import { Client, RPCConnection } from 'json-rpc2';
import { parseEnvFile, getBinPathWithPreferredGopath, getInferredGopath, getCurrentGoWorkspaceFromGOPATH, envPath, fixDriveCasingInWindows } from '../goPath';

const fsAccess = util.promisify(fs.access);
const fsUnlink = util.promisify(fs.unlink);

// This enum should stay in sync with https://golang.org/pkg/reflect/#Kind

enum GoReflectKind {
	Invalid = 0,
	Bool,
	Int,
	Int8,
	Int16,
	Int32,
	Int64,
	Uint,
	Uint8,
	Uint16,
	Uint32,
	Uint64,
	Uintptr,
	Float32,
	Float64,
	Complex64,
	Complex128,
	Array,
	Chan,
	Func,
	Interface,
	Map,
	Ptr,
	Slice,
	String,
	Struct,
	UnsafePointer
}

// These types should stay in sync with:
// https://github.com/go-delve/delve/blob/master/service/api/types.go

interface CommandOut {
	State: DebuggerState;
}

interface DebuggerState {
	exited: boolean;
	exitStatus: number;
	breakPoint: DebugBreakpoint;
	breakPointInfo: {};
	currentThread: DebugThread;
	currentGoroutine: DebugGoroutine;
	Running: boolean;
}

interface CreateBreakpointOut {
	Breakpoint: DebugBreakpoint;
}

interface GetVersionOut {
	DelveVersion: string;
	APIVersion: number;
}

interface DebugBreakpoint {
	addr: number;
	continue: boolean;
	file: string;
	functionName?: string;
	goroutine: boolean;
	id: number;
	name: string;
	line: number;
	stacktrace: number;
	variables?: DebugVariable[];
	loadArgs?: LoadConfig;
	loadLocals?: LoadConfig;
	cond?: string;
}

interface LoadConfig {
	// FollowPointers requests pointers to be automatically dereferenced.
	followPointers: boolean;
	// MaxVariableRecurse is how far to recurse when evaluating nested types.
	maxVariableRecurse: number;
	// MaxStringLen is the maximum number of bytes read from a string
	maxStringLen: number;
	// MaxArrayValues is the maximum number of elements read from an array, a slice or a map.
	maxArrayValues: number;
	// MaxStructFields is the maximum number of fields read from a struct, -1 will read all fields.
	maxStructFields: number;
}

interface DebugThread {
	file: string;
	id: number;
	line: number;
	pc: number;
	function?: DebugFunction;
}

interface StacktraceOut {
	Locations: DebugLocation[];
}

interface DebugLocation {
	pc: number;
	file: string;
	line: number;
	function: DebugFunction;
}

interface DebugFunction {
	name: string;
	value: number;
	type: number;
	goType: number;
	args: DebugVariable[];
	locals: DebugVariable[];
}

interface ListVarsOut {
	Variables: DebugVariable[];
}

interface ListFunctionArgsOut {
	Args: DebugVariable[];
}

interface EvalOut {
	Variable: DebugVariable;
}

enum GoVariableFlags {
	VariableEscaped = 1,
	VariableShadowed = 2,
	VariableConstant = 4,
	VariableArgument = 8,
	VariableReturnArgument = 16
}

interface DebugVariable {
	name: string;
	addr: number;
	type: string;
	realType: string;
	kind: GoReflectKind;
	flags: GoVariableFlags;
	onlyAddr: boolean;
	DeclLine: number;
	value: string;
	len: number;
	cap: number;
	children: DebugVariable[];
	unreadable: string;
	fullyQualifiedName: string;
	base: number;
}

interface ListGoroutinesOut {
	Goroutines: DebugGoroutine[];
}

interface DebugGoroutine {
	id: number;
	currentLoc: DebugLocation;
	userCurrentLoc: DebugLocation;
	goStatementLoc: DebugLocation;
}

interface DebuggerCommand {
	name: string;
	threadID?: number;
	goroutineID?: number;
}

interface ListBreakpointsOut {
	Breakpoints: DebugBreakpoint[];
}

interface RestartOut {
	DiscardedBreakpoints: DiscardedBreakpoint[];
}

interface DiscardedBreakpoint {
	breakpoint: DebugBreakpoint;
	reason: string;
}

// This interface should always match the schema found in `package.json`.
interface LaunchRequestArguments extends DebugProtocol.LaunchRequestArguments {
	request: 'launch';
	[key: string]: any;
	program: string;
	stopOnEntry?: boolean;
	args?: string[];
	showLog?: boolean;
	logOutput?: string;
	cwd?: string;
	env?: { [key: string]: string; };
	mode?: 'auto' | 'debug' | 'remote' | 'test' | 'exec';
	remotePath?: string;
	port?: number;
	host?: string;
	buildFlags?: string;
	init?: string;
	trace?: 'verbose' | 'log' | 'error';
	/** Optional path to .env file. */
	envFile?: string;
	backend?: string;
	output?: string;
	/** Delve LoadConfig parameters **/
	dlvLoadConfig?: LoadConfig;
	dlvToolPath: string;
	/** Delve Version */
	apiVersion: number;
	/** Delve maximum stack trace depth */
	stackTraceDepth: number;

	showGlobalVariables?: boolean;
	currentFile: string;
	packagePathToGoModPathMap: {[key: string]: string};
}

interface AttachRequestArguments extends DebugProtocol.AttachRequestArguments {
	request: 'attach';
	processId?: number;
	stopOnEntry?: boolean;
	showLog?: boolean;
	logOutput?: string;
	cwd?: string;
	mode?: 'local' | 'remote';
	remotePath?: string;
	port?: number;
	host?: string;
	trace?: 'verbose' | 'log' | 'error';
	backend?: string;
	/** Delve LoadConfig parameters **/
	dlvLoadConfig?: LoadConfig;
	dlvToolPath: string;
	/** Delve Version */
	apiVersion: number;
	/** Delve maximum stack trace depth */
	stackTraceDepth: number;

	showGlobalVariables?: boolean;
	currentFile: string;
}

process.on('uncaughtException', (err: any) => {
	const errMessage = err && (err.stack || err.message);
	logger.error(`Unhandled error in debug adapter: ${errMessage}`);
	throw err;
});

function logArgsToString(args: any[]): string {
	return args.map(arg => {
		return typeof arg === 'string' ?
			arg :
			JSON.stringify(arg);
	}).join(' ');
}

function log(...args: any[]) {
	logger.warn(logArgsToString(args));
}

function logError(...args: any[]) {
	logger.error(logArgsToString(args));
}

function normalizePath(filePath: string) {
	if (process.platform === 'win32') {
		filePath = path.normalize(filePath);
		return fixDriveCasingInWindows(filePath);
	}
	return filePath;
}

class Delve {
	program: string;
	remotePath: string;
	localDebugeePath: string | undefined;
	debugProcess: ChildProcess;
	loadConfig: LoadConfig;
	connection: Promise<RPCConnection>;
	onstdout: (str: string) => void;
	onstderr: (str: string) => void;
	onclose: (code: number) => void;
	noDebug: boolean;
	isApiV1: boolean;
	dlvEnv: any;
	stackTraceDepth: number;
	isRemoteDebugging: boolean;
	request: 'attach' | 'launch';

	constructor(launchArgs: LaunchRequestArguments | AttachRequestArguments, program: string) {
		this.request = launchArgs.request;
		this.program = normalizePath(program);
		this.remotePath = launchArgs.remotePath;
		this.isApiV1 = false;
		if (typeof launchArgs.apiVersion === 'number') {
			this.isApiV1 = launchArgs.apiVersion === 1;
		}
		this.stackTraceDepth = typeof launchArgs.stackTraceDepth === 'number' ? launchArgs.stackTraceDepth : 50;
		this.connection = new Promise((resolve, reject) => {
			const mode = launchArgs.mode;
			let dlvCwd = dirname(program);
			let serverRunning = false;
			const dlvArgs = new Array<string>();

			// Get default LoadConfig values according to delve API:
			// https://github.com/go-delve/delve/blob/c5c41f635244a22d93771def1c31cf1e0e9a2e63/service/rpc1/server.go#L13
			// https://github.com/go-delve/delve/blob/c5c41f635244a22d93771def1c31cf1e0e9a2e63/service/rpc2/server.go#L423
			this.loadConfig = launchArgs.dlvLoadConfig || {
				followPointers: true,
				maxVariableRecurse: 1,
				maxStringLen: 64,
				maxArrayValues: 64,
				maxStructFields: -1
			};

			if (mode === 'remote') {
				this.debugProcess = null;
				this.isRemoteDebugging = true;
				serverRunning = true;  // assume server is running when in remote mode
				connectClient(launchArgs.port, launchArgs.host);
				return;
			}
			this.isRemoteDebugging = false;
			let env: NodeJS.ProcessEnv;
			if (launchArgs.request === 'launch') {
				let isProgramDirectory = false;
				// Validations on the program
				if (!program) {
					return reject('The program attribute is missing in the debug configuration in launch.json');
				}
				try {
					const pstats = lstatSync(program);
					if (pstats.isDirectory()) {
						if (mode === 'exec') {
							logError(`The program "${program}" must not be a directory in exec mode`);
							return reject('The program attribute must be an executable in exec mode');
						}
						dlvCwd = program;
						isProgramDirectory = true;
					} else if (mode !== 'exec' && extname(program) !== '.go') {
						logError(`The program "${program}" must be a valid go file in debug mode`);
						return reject('The program attribute must be a directory or .go file in debug mode');
					}
				} catch (e) {
					logError(`The program "${program}" does not exist: ${e}`);
					return reject('The program attribute must point to valid directory, .go file or executable.');
				}

				// read env from disk and merge into env variables
				let fileEnv = {};
				try {
					fileEnv = parseEnvFile(launchArgs.envFile);
				} catch (e) {
					return reject(e);
				}

				const launchArgsEnv = launchArgs.env || {};
				env = Object.assign({}, process.env, fileEnv, launchArgsEnv);

				const dirname = isProgramDirectory ? program : path.dirname(program);
				if (!env['GOPATH'] && (mode === 'debug' || mode === 'test')) {
					// If no GOPATH is set, then infer it from the file/package path
					// Not applicable to exec mode in which case `program` need not point to source code under GOPATH
					env['GOPATH'] = getInferredGopath(dirname) || env['GOPATH'];
				}
				this.dlvEnv = env;
				log(`Using GOPATH: ${env['GOPATH']}`);

				if (!!launchArgs.noDebug) {
					if (mode === 'debug') {
						if (isProgramDirectory && launchArgs.currentFile) {
							program = launchArgs.currentFile;
							isProgramDirectory = false;
						}

						if (!isProgramDirectory) {
							this.noDebug = true;
							const runArgs = ['run'];
							if (launchArgs.buildFlags) {
								runArgs.push(launchArgs.buildFlags);
							}
							runArgs.push(program);
							if (launchArgs.args) {
								runArgs.push(...launchArgs.args);
							}
							this.debugProcess = spawn(getBinPathWithPreferredGopath('go', []), runArgs, { env });
							this.debugProcess.stderr.on('data', chunk => {
								const str = chunk.toString();
								if (this.onstderr) { this.onstderr(str); }
							});
							this.debugProcess.stdout.on('data', chunk => {
								const str = chunk.toString();
								if (this.onstdout) { this.onstdout(str); }
							});
							this.debugProcess.on('close', (code) => {
								logError('Process exiting with code: ' + code);
								if (this.onclose) { this.onclose(code); }
							});
							this.debugProcess.on('error', (err) => {
								reject(err);
							});
							resolve();
							return;
						}
					}
				}
				this.noDebug = false;

				if (!existsSync(launchArgs.dlvToolPath)) {
					log(`Couldn't find dlv at the Go tools path, ${process.env['GOPATH']}${env['GOPATH'] ? ', ' + env['GOPATH'] : ''} or ${envPath}`);
					return reject(`Cannot find Delve debugger. Install from https://github.com/derekparker/delve & ensure it is in your Go tools path, "GOPATH/bin" or "PATH".`);
				}

				const currentGOWorkspace = getCurrentGoWorkspaceFromGOPATH(env['GOPATH'], dirname);
				dlvArgs.push(mode || 'debug');
				if (mode === 'exec') {
					dlvArgs.push(program);
				} else if (currentGOWorkspace && !launchArgs.packagePathToGoModPathMap[dirname]) {
					dlvArgs.push(dirname.substr(currentGOWorkspace.length + 1));
				}
				dlvArgs.push('--headless=true', `--listen=${launchArgs.host}:${launchArgs.port}`);
				if (!this.isApiV1) {
					dlvArgs.push('--api-version=2');
				}

				if (launchArgs.showLog) {
					dlvArgs.push('--log=' + launchArgs.showLog.toString());
				}
				if (launchArgs.logOutput) {
					dlvArgs.push('--log-output=' + launchArgs.logOutput);
				}
				if (launchArgs.cwd) {
					dlvArgs.push('--wd=' + launchArgs.cwd);
				}
				if (launchArgs.buildFlags) {
					dlvArgs.push('--build-flags=' + launchArgs.buildFlags);
				}
				if (launchArgs.init) {
					dlvArgs.push('--init=' + launchArgs.init);
				}
				if (launchArgs.backend) {
					dlvArgs.push('--backend=' + launchArgs.backend);
				}
				if (launchArgs.output && (mode === 'debug' || mode === 'test')) {
					dlvArgs.push('--output=' + launchArgs.output);
				}
				if (launchArgs.args && launchArgs.args.length > 0) {
					dlvArgs.push('--', ...launchArgs.args);
				}
				this.localDebugeePath = this.getLocalDebugeePath(launchArgs.output);
			} else if (launchArgs.request === 'attach') {
				if (!launchArgs.processId) {
					return reject(`Missing process ID`);
				}

				if (!existsSync(launchArgs.dlvToolPath)) {
					return reject(`Cannot find Delve debugger. Install from https://github.com/go-delve/delve & ensure it is in your Go tools path, "GOPATH/bin" or "PATH".`);
				}

				dlvArgs.push('attach', `${launchArgs.processId}`);
				dlvArgs.push('--headless=true', '--listen=' + launchArgs.host + ':' + launchArgs.port.toString());
				if (!this.isApiV1) {
					dlvArgs.push('--api-version=2');
				}

				if (launchArgs.showLog) {
					dlvArgs.push('--log=' + launchArgs.showLog.toString());
				}
				if (launchArgs.logOutput) {
					dlvArgs.push('--log-output=' + launchArgs.logOutput);
				}
				if (launchArgs.cwd) {
					dlvArgs.push('--wd=' + launchArgs.cwd);
				}
				if (launchArgs.backend) {
					dlvArgs.push('--backend=' + launchArgs.backend);
				}
			}

			log(`Current working directory: ${dlvCwd}`);
			log(`Running: ${launchArgs.dlvToolPath} ${dlvArgs.join(' ')}`);

			this.debugProcess = spawn(launchArgs.dlvToolPath, dlvArgs, {
				cwd: dlvCwd,
				env,
			});

			function connectClient(port: number, host: string) {
				// Add a slight delay to avoid issues on Linux with
				// Delve failing calls made shortly after connection.
				setTimeout(() => {
					const client = Client.$create(port, host);
					client.connectSocket((err, conn) => {
						if (err) {
							return reject(err);
						}
						return resolve(conn);
					});
				}, 200);
			}

			this.debugProcess.stderr.on('data', chunk => {
				const str = chunk.toString();
				if (this.onstderr) { this.onstderr(str); }
			});
			this.debugProcess.stdout.on('data', chunk => {
				const str = chunk.toString();
				if (this.onstdout) { this.onstdout(str); }
				if (!serverRunning) {
					serverRunning = true;
					connectClient(launchArgs.port, launchArgs.host);
				}
			});
			this.debugProcess.on('close', (code) => {
				// TODO: Report `dlv` crash to user.
				logError('Process exiting with code: ' + code);
				if (this.onclose) { this.onclose(code); }
			});
			this.debugProcess.on('error', (err) => {
				reject(err);
			});
		});
	}

	public call<T>(command: string, args: any[], callback: (err: Error, results: T) => void) {
		this.connection.then(conn => {
			conn.call('RPCServer.' + command, args, callback);
		}, err => {
			callback(err, null);
		});
	}

	public callPromise<T>(command: string, args: any[]): Thenable<T> {
		return new Promise<T>((resolve, reject) => {
			this.connection.then(conn => {
				conn.call<T>(`RPCServer.${command}`, args, (err, res) => {
					return err ? reject(err) : resolve(res);
				});
			}, err => {
				reject(err);
			});
		});
	}

	/**
	 * Returns the current state of the delve debugger.
	 * This method does not block delve and should return immediately.
	 */
	public async getDebugState(): Promise<DebuggerState> {
		// If a program is launched with --continue, the program is running
		// before we can run attach. So we would need to check the state.
		// We use NonBlocking so the call would return immediately.
		const callResult = await this.callPromise<DebuggerState | CommandOut>('State', [{ NonBlocking: true }]);
		return this.isApiV1 ? <DebuggerState>callResult : (<CommandOut>callResult).State;
	}

	/**
	 * Closing a debugging session follows different approaches for launch vs attach debugging.
	 *
	 * For launch debugging, since the extension starts the delve process, the extension should close it as well.
	 * To gracefully clean up the assets created by delve, we send the Detach request with kill option set to true.
	 *
	 * For attach debugging there are two scenarios; attaching to a local process by ID or connecting to a
	 * remote delve server.  For attach-local we start the delve process so will also terminate it however we
	 * detach from the debugee without killing it.  For attach-remote we only detach from delve.
	 *
	 * The only way to detach from delve when it is running a program is to send a Halt request first.
	 * Since the Halt request might sometimes take too long to complete, we have a timer in place to forcefully kill
	 * the debug process and clean up the assets in case of local debugging
	 */
	public close(): Thenable<void> {
		if (this.noDebug) {
			// delve isn't running so no need to halt
			return Promise.resolve();
		}
		log('HaltRequest');

		const isLocalDebugging: boolean = this.request === 'launch' && !!this.debugProcess;
		const forceCleanup = async () => {
			killTree(this.debugProcess.pid);
			await removeFile(this.localDebugeePath);
		};
		return new Promise(async resolve => {
			// For remote debugging, closing the connection would terminate the
			// program as well so we just want to disconnect.
			// See https://www.github.com/go-delve/delve/issues/1587
			if (this.isRemoteDebugging) {
				const rpcConnection = await this.connection;
				// tslint:disable-next-line no-any
				(rpcConnection as any)['conn']['end']();
				return;
			}
			const timeoutToken: NodeJS.Timer = isLocalDebugging && setTimeout(async () => {
				log('Killing debug process manually as we could not halt delve in time');
				await forceCleanup();
				resolve();
			}, 1000);

			let haltErrMsg: string;
			try {
				await this.callPromise('Command', [{ name: 'halt' }]);
			} catch (err) {
				log('HaltResponse');
				haltErrMsg = err ? err.toString() : '';
				log(`Failed to halt - ${haltErrMsg}`);
			}
			clearTimeout(timeoutToken);

			const targetHasExited: boolean = haltErrMsg && haltErrMsg.endsWith('has exited with status 0');
			const shouldDetach: boolean = !haltErrMsg || targetHasExited;
			let shouldForceClean: boolean = !shouldDetach && isLocalDebugging;
			if (shouldDetach) {
				log('DetachRequest');
				try {
					await this.callPromise('Detach', [this.isApiV1 ? true : { Kill: isLocalDebugging }]);
				} catch (err) {
					log('DetachResponse');
					logError(`Failed to detach - ${(err.toString() || '')}`);
					shouldForceClean = isLocalDebugging;
				}
			}
			if (shouldForceClean) {
				await forceCleanup();
			}
			return resolve();
		});
	}

	private getLocalDebugeePath(output: string | undefined): string {
		const configOutput = output || 'debug';
		return path.isAbsolute(configOutput)
			? configOutput
			: path.resolve(this.program, configOutput);
	}
}

class GoDebugSession extends LoggingDebugSession {

	private variableHandles: Handles<DebugVariable>;
	private breakpoints: Map<string, DebugBreakpoint[]>;
	private skipStopEventOnce: boolean; // Editing breakpoints requires halting delve, skip sending Stop Event to VS Code in such cases
	private goroutines: Set<number>;
	private debugState: DebuggerState;
	private delve: Delve;
	private localPathSeparator: string;
	private remotePathSeparator: string;
	private stackFrameHandles: Handles<[number, number]>;
	private packageInfo = new Map<string, string>();
	private stopOnEntry: boolean;
	private logLevel: Logger.LogLevel = Logger.LogLevel.Error;
	private readonly initdone = 'initdone·';

	private showGlobalVariables: boolean = false;
	public constructor(debuggerLinesStartAt1: boolean, isServer: boolean = false) {
		super('', debuggerLinesStartAt1, isServer);
		this.variableHandles = new Handles<DebugVariable>();
		this.skipStopEventOnce = false;
		this.stopOnEntry = false;
		this.goroutines = new Set<number>();
		this.debugState = null;
		this.delve = null;
		this.breakpoints = new Map<string, DebugBreakpoint[]>();
		this.stackFrameHandles = new Handles<[number, number]>();
	}

	protected initializeRequest(response: DebugProtocol.InitializeResponse, args: DebugProtocol.InitializeRequestArguments): void {
		log('InitializeRequest');
		// This debug adapter implements the configurationDoneRequest.
		response.body.supportsConfigurationDoneRequest = true;
		response.body.supportsSetVariable = true;
		this.sendResponse(response);
		log('InitializeResponse');
	}

	protected findPathSeperator(path: string) {
		if (/^(\w:[\\/]|\\\\)/.test(path)) {
			return '\\';
		}
		return path.includes('/') ? '/' : '\\';
	}

	// contains common code for launch and attach debugging initialization
	private initLaunchAttachRequest(response: DebugProtocol.LaunchResponse, args: LaunchRequestArguments | AttachRequestArguments) {
		this.logLevel = args.trace === 'verbose' ?
			Logger.LogLevel.Verbose :
			args.trace === 'log' ? Logger.LogLevel.Log :
				Logger.LogLevel.Error;
		const logPath = this.logLevel !== Logger.LogLevel.Error ? path.join(os.tmpdir(), 'vscode-go-debug.txt') : undefined;
		logger.setup(this.logLevel, logPath);

		if (typeof (args.showGlobalVariables) === 'boolean') {
			this.showGlobalVariables = args.showGlobalVariables;
		}
		if (args.stopOnEntry) {
			this.stopOnEntry = args.stopOnEntry;
		}
		if (!args.port) {
			args.port = random(2000, 50000);
		}
		if (!args.host) {
			args.host = '127.0.0.1';
		}

		let localPath: string;
		if (args.request === 'attach') {
			localPath = args.cwd;
		} else if (args.request === 'launch') {
			localPath = args.program;
		}
		if (!args.remotePath) {
			// too much code relies on remotePath never being null
			args.remotePath = '';
		}

		if (args.remotePath.length > 0) {
			this.localPathSeparator = this.findPathSeperator(localPath);
			this.remotePathSeparator = this.findPathSeperator(args.remotePath);

			const llist = localPath.split(/\/|\\/).reverse();
			const rlist = args.remotePath.split(/\/|\\/).reverse();
			let i = 0;
			for (; i < llist.length; i++) {
				if (llist[i] !== rlist[i] || llist[i] === 'src') {
					break;
				}
			}

			if (i) {
				localPath = llist.reverse().slice(0, -i).join(this.localPathSeparator) + this.localPathSeparator;
				args.remotePath = rlist.reverse().slice(0, -i).join(this.remotePathSeparator) + this.remotePathSeparator;
			} else if (args.remotePath.length > 1 &&
				(args.remotePath.endsWith('\\') || args.remotePath.endsWith('/'))) {
				args.remotePath = args.remotePath.substring(0, args.remotePath.length - 1);
			}
		}

		// Launch the Delve debugger on the program
		this.delve = new Delve(args, localPath);
		this.delve.onstdout = (str: string) => {
			this.sendEvent(new OutputEvent(str, 'stdout'));
		};
		this.delve.onstderr = (str: string) => {
			this.sendEvent(new OutputEvent(str, 'stderr'));
		};
		this.delve.onclose = (code) => {
			if (code !== 0) {
				this.sendErrorResponse(response, 3000, 'Failed to continue: Check the debug console for details.');
			}
			log('Sending TerminatedEvent as delve is closed');
			this.sendEvent(new TerminatedEvent());
		};

		this.delve.connection.then(() => {
			if (!this.delve.noDebug) {
				this.delve.call<GetVersionOut>('GetVersion', [], (err, out) => {
					if (err) {
						logError(err);
						return this.sendErrorResponse(response, 2001, 'Failed to get remote server version: "{e}"', { e: err.toString() });
					}
					const clientVersion = this.delve.isApiV1 ? 1 : 2;
					if (out.APIVersion !== clientVersion) {
						const errorMessage = `The remote server is running on delve v${out.APIVersion} API and the client is running v${clientVersion} API. Change the version used on the client by using the property "apiVersion" in your launch.json file.`;
						logError(errorMessage);
						return this.sendErrorResponse(response,
							3000,
							errorMessage);
					}
				});

				this.sendEvent(new InitializedEvent());
				log('InitializeEvent');
			}
			this.sendResponse(response);
		}, err => {
			this.sendErrorResponse(response, 3000, 'Failed to continue: "{e}"', { e: err.toString() });
			log('ContinueResponse');
		});
	}

	protected launchRequest(response: DebugProtocol.LaunchResponse, args: LaunchRequestArguments): void {
		if (!args.program) {
			this.sendErrorResponse(response, 3000, 'Failed to continue: The program attribute is missing in the debug configuration in launch.json');
			return;
		}
		this.initLaunchAttachRequest(response, args);
	}

	protected attachRequest(response: DebugProtocol.AttachResponse, args: AttachRequestArguments): void {
		if (args.mode === 'local' && !args.processId) {
			this.sendErrorResponse(response, 3000, 'Failed to continue: the processId attribute is missing in the debug configuration in launch.json');
		} else if (args.mode === 'remote' && !args.port) {
			this.sendErrorResponse(response, 3000, 'Failed to continue: the port attribute is missing in the debug configuration in launch.json');
		}
		this.initLaunchAttachRequest(response, args);
	}

	protected async disconnectRequest(response: DebugProtocol.DisconnectResponse, args: DebugProtocol.DisconnectArguments): Promise<void> {
		log('DisconnectRequest');
		// For remote process, we have to issue a continue request
		// before disconnecting.
		if (this.delve.isRemoteDebugging) {
			// We don't have to wait for continue call
			// because we are not doing anything with the result.
			// Also, DisconnectRequest will return before
			// we get the result back from delve.
			this.debugState = await this.delve.getDebugState();
			if (!this.debugState.Running) {
				this.continue();
			}
		}
		this.delve.close().then(() => {
			log('DisconnectRequest to parent');
			super.disconnectRequest(response, args);
			log('DisconnectResponse');
		});
	}

	protected async configurationDoneRequest(response: DebugProtocol.ConfigurationDoneResponse, args: DebugProtocol.ConfigurationDoneArguments): Promise<void> {
		log('ConfigurationDoneRequest');
		if (this.stopOnEntry) {
			this.sendEvent(new StoppedEvent('breakpoint', 1));
			log('StoppedEvent("breakpoint")');
			this.sendResponse(response);
		} else {
			this.debugState = await this.delve.getDebugState();
			if (!this.debugState.Running) {
				this.continueRequest(<DebugProtocol.ContinueResponse>response);
			}
		}
	}

	protected toDebuggerPath(path: string): string {
		if (this.delve.remotePath.length === 0) {
			return this.convertClientPathToDebugger(path);
		}
		return path.replace(this.delve.program, this.delve.remotePath).split(this.localPathSeparator).join(this.remotePathSeparator);
	}

	protected toLocalPath(pathToConvert: string): string {
		if (this.delve.remotePath.length === 0) {
			return this.convertDebuggerPathToClient(pathToConvert);
		}

		// Fix for https://github.com/Microsoft/vscode-go/issues/1178
		// When the pathToConvert is under GOROOT, replace the remote GOROOT with local GOROOT
		if (!pathToConvert.startsWith(this.delve.remotePath)) {
			const index = pathToConvert.indexOf(`${this.remotePathSeparator}src${this.remotePathSeparator}`);
			const goroot = process.env['GOROOT'];
			if (goroot && index > 0) {
				return path.join(goroot, pathToConvert.substr(index));
			}
		}
		return pathToConvert.replace(this.delve.remotePath, this.delve.program).split(this.remotePathSeparator).join(this.localPathSeparator);
	}

	private updateGoroutinesList(goroutines: DebugGoroutine[]): void {
		// Assume we need to stop all the threads we saw before...
		const needsToBeStopped = new Set<number>();
		this.goroutines.forEach(id => needsToBeStopped.add(id));
		for (const goroutine of goroutines) {
			// ...but delete from list of threads to stop if we still see it
			needsToBeStopped.delete(goroutine.id);
			if (!this.goroutines.has(goroutine.id)) {
				// Send started event if it's new
				this.sendEvent(new ThreadEvent('started', goroutine.id));
			}
			this.goroutines.add(goroutine.id);
		}
		// Send existed event if it's no longer there
		needsToBeStopped.forEach(id => {
			this.sendEvent(new ThreadEvent('exited', id));
			this.goroutines.delete(id);
		});
	}

	private setBreakPoints(response: DebugProtocol.SetBreakpointsResponse, args: DebugProtocol.SetBreakpointsArguments): Thenable<void> {
		const file = normalizePath(args.source.path);
		if (!this.breakpoints.get(file)) {
			this.breakpoints.set(file, []);
		}
		const remoteFile = this.toDebuggerPath(file);

		return Promise.all(this.breakpoints.get(file).map(existingBP => {
			log('Clearing: ' + existingBP.id);
			return this.delve.callPromise('ClearBreakpoint', [this.delve.isApiV1 ? existingBP.id : { Id: existingBP.id }]);
		})).then(() => {
			log('All cleared');
			let existingBreakpoints: DebugBreakpoint[] | undefined;
			return Promise.all(args.breakpoints.map(breakpoint => {
				if (this.delve.remotePath.length === 0) {
					log('Creating on: ' + file + ':' + breakpoint.line);
				} else {
					log('Creating on: ' + file + ' (' + remoteFile + ') :' + breakpoint.line);
				}
				const breakpointIn = <DebugBreakpoint>{};
				breakpointIn.file = remoteFile;
				breakpointIn.line = breakpoint.line;
				breakpointIn.loadArgs = this.delve.loadConfig;
				breakpointIn.loadLocals = this.delve.loadConfig;
				breakpointIn.cond = breakpoint.condition;
				return this.delve.callPromise('CreateBreakpoint', [this.delve.isApiV1 ? breakpointIn : { Breakpoint: breakpointIn }]).then(null,
					async (err) => {
						// Delve does not seem to support error code at this time.
						// TODO(quoct): Follow up with delve team.
						if (err.toString().startsWith('Breakpoint exists at')) {
							log('Encounter existing breakpoint: ' + breakpointIn);
							// We need to call listbreakpoints to find the ID.
							// Otherwise, we would not be able to clear the breakpoints.
							if (!existingBreakpoints) {
								try {
									const listBreakpointsResponse =
										await this.delve.callPromise<ListBreakpointsOut | DebugBreakpoint[]>('ListBreakpoints', this.delve.isApiV1 ? [] : [{}]);
									existingBreakpoints = this.delve.isApiV1 ?
										listBreakpointsResponse as DebugBreakpoint[] : (listBreakpointsResponse as ListBreakpointsOut).Breakpoints;
								} catch (error) {
									log('Error listing breakpoints: ' + error.toString());
									return null;
								}
							}
							const matchedBreakpoint = existingBreakpoints.find(breakpoint =>
								breakpoint.line === breakpointIn.line && breakpoint.file === breakpointIn.file);
							if (!matchedBreakpoint) {
								log(`Cannot match breakpoint ${breakpointIn} with existing breakpoints.`);
								return null;
							}
							return this.delve.isApiV1 ? matchedBreakpoint : { Breakpoint: matchedBreakpoint };
						}
						log('Error on CreateBreakpoint: ' + err.toString());
						return null;
					});
			}));
		}).then(newBreakpoints => {
			let convertedBreakpoints: DebugBreakpoint[];
			if (!this.delve.isApiV1) {
				// Unwrap breakpoints from v2 apicall
				convertedBreakpoints = newBreakpoints.map((bp, i) => {
					return bp ? (bp as CreateBreakpointOut).Breakpoint : null;
				});
			} else {
				convertedBreakpoints = newBreakpoints as DebugBreakpoint[];
			}

			log('All set:' + JSON.stringify(newBreakpoints));
			const breakpoints = convertedBreakpoints.map((bp, i) => {
				if (bp) {
					return { verified: true, line: bp.line };
				} else {
					return { verified: false, line: args.lines[i] };
				}
			});
			this.breakpoints.set(file, convertedBreakpoints.filter(x => !!x));
			return breakpoints;
		}).then(breakpoints => {
			response.body = { breakpoints };
			this.sendResponse(response);
			log('SetBreakPointsResponse');
		}, err => {
			this.sendErrorResponse(response, 2002, 'Failed to set breakpoint: "{e}"', { e: err.toString() });
			logError(err);
		});
	}

	protected async setBreakPointsRequest(response: DebugProtocol.SetBreakpointsResponse, args: DebugProtocol.SetBreakpointsArguments): Promise<void> {
		log('SetBreakPointsRequest');
		try {
			// If a program is launched with --continue, the program is running
			// before we can run attach. So we would need to check the state.
			// We use NonBlocking so the call would return immediately.
			this.debugState = await this.delve.getDebugState();
		} catch (error) {
			logError(`Failed to get state ${String(error)}`);
		}

		if (!this.debugState.Running && !this.continueRequestRunning) {
			await this.setBreakPoints(response, args);
		} else {
			this.skipStopEventOnce = this.continueRequestRunning;
			this.delve.callPromise('Command', [{ name: 'halt' }]).then(() => {
				return this.setBreakPoints(response, args).then(() => {
					return this.continue(true).then(null, err => {
						logError(`Failed to continue delve after halting it to set breakpoints: "${err.toString()}"`);
					});
				});
			}, err => {
				this.skipStopEventOnce = false;
				logError(err);
				return this.sendErrorResponse(response, 2008, 'Failed to halt delve before attempting to set breakpoint: "{e}"', { e: err.toString() });
			});
		}
	}

	protected threadsRequest(response: DebugProtocol.ThreadsResponse): void {
		if (this.continueRequestRunning) {
			// Thread request to delve is syncronous and will block if a previous async continue request didn't return
			response.body = { threads: [new Thread(1, 'Dummy')] };
			return this.sendResponse(response);
		}
		log('ThreadsRequest');
		this.delve.call<DebugGoroutine[] | ListGoroutinesOut>('ListGoroutines', [], (err, out) => {
			if (this.debugState && this.debugState.exited) {
				// If the program exits very quickly, the initial threadsRequest will complete after it has exited.
				// A TerminatedEvent has already been sent. Ignore the err returned in this case.
				response.body = { threads: [] };
				return this.sendResponse(response);
			}

			if (err) {
				logError('Failed to get threads - ' + err.toString());
				return this.sendErrorResponse(response, 2003, 'Unable to display threads: "{e}"', { e: err.toString() });
			}
			const goroutines = this.delve.isApiV1 ? <DebugGoroutine[]>out : (<ListGoroutinesOut>out).Goroutines;
			log('goroutines', goroutines);
			this.updateGoroutinesList(goroutines);
			const threads = goroutines.map(goroutine =>
				new Thread(
					goroutine.id,
					goroutine.userCurrentLoc.function ? goroutine.userCurrentLoc.function.name : (goroutine.userCurrentLoc.file + '@' + goroutine.userCurrentLoc.line)
				)
			);
			if (threads.length === 0) {
				threads.push(new Thread(1, 'Dummy'));
			}
			response.body = { threads };
			this.sendResponse(response);
			log('ThreadsResponse', threads);
		});
	}

	protected stackTraceRequest(response: DebugProtocol.StackTraceResponse, args: DebugProtocol.StackTraceArguments): void {
		log('StackTraceRequest');
		// delve does not support frame paging, so we ask for a large depth
		const goroutineId = args.threadId;
		const stackTraceIn = { id: goroutineId, depth: this.delve.stackTraceDepth };
		if (!this.delve.isApiV1) {
			Object.assign(stackTraceIn, { full: false, cfg: this.delve.loadConfig });
		}
		this.delve.call<DebugLocation[] | StacktraceOut>(this.delve.isApiV1 ? 'StacktraceGoroutine' : 'Stacktrace', [stackTraceIn], (err, out) => {
			if (err) {
				logError('Failed to produce stack trace!');
				return this.sendErrorResponse(response, 2004, 'Unable to produce stack trace: "{e}"', { e: err.toString() });
			}
			const locations = this.delve.isApiV1 ? <DebugLocation[]>out : (<StacktraceOut>out).Locations;
			log('locations', locations);
			let stackFrames = locations.map((location, frameId) => {
				const uniqueStackFrameId = this.stackFrameHandles.create([goroutineId, frameId]);
				return new StackFrame(
					uniqueStackFrameId,
					location.function ? location.function.name : '<unknown>',
					location.file === '<autogenerated>' ? null : new Source(
						basename(location.file),
						this.toLocalPath(location.file)
					),
					location.line,
					0
				);
			});
			if (args.startFrame > 0) {
				stackFrames = stackFrames.slice(args.startFrame);
			}
			if (args.levels > 0) {
				stackFrames = stackFrames.slice(0, args.levels);
			}
			response.body = { stackFrames, totalFrames: locations.length };
			this.sendResponse(response);
			log('StackTraceResponse');
		});
	}

	protected scopesRequest(response: DebugProtocol.ScopesResponse, args: DebugProtocol.ScopesArguments): void {
		log('ScopesRequest');
		const [goroutineId, frameId] = this.stackFrameHandles.get(args.frameId);
		const listLocalVarsIn = { goroutineID: goroutineId, frame: frameId };
		this.delve.call<DebugVariable[] | ListVarsOut>('ListLocalVars', this.delve.isApiV1 ? [listLocalVarsIn] : [{ scope: listLocalVarsIn, cfg: this.delve.loadConfig }], (err, out) => {
			if (err) {
				logError('Failed to list local variables - ' + err.toString());
				return this.sendErrorResponse(response, 2005, 'Unable to list locals: "{e}"', { e: err.toString() });
			}
			const locals = this.delve.isApiV1 ? <DebugVariable[]>out : (<ListVarsOut>out).Variables;
			log('locals', locals);
			this.addFullyQualifiedName(locals);
			const listLocalFunctionArgsIn = { goroutineID: goroutineId, frame: frameId };
			this.delve.call<DebugVariable[] | ListFunctionArgsOut>('ListFunctionArgs', this.delve.isApiV1 ? [listLocalFunctionArgsIn] : [{ scope: listLocalFunctionArgsIn, cfg: this.delve.loadConfig }], (err, outArgs) => {
				if (err) {
					logError('Failed to list function args - ' + err.toString());
					return this.sendErrorResponse(response, 2006, 'Unable to list args: "{e}"', { e: err.toString() });
				}
				const args = this.delve.isApiV1 ? <DebugVariable[]>outArgs : (<ListFunctionArgsOut>outArgs).Args;
				log('functionArgs', args);
				this.addFullyQualifiedName(args);
				const vars = args.concat(locals);
				// annotate shadowed variables in parentheses
				const shadowedVars = new Map<string, Array<number>>();
				for (let i = 0; i < vars.length; ++i) {
					if ((vars[i].flags & GoVariableFlags.VariableShadowed) === 0) {
						continue;
					}
					const varName = vars[i].name;
					if (!shadowedVars.has(varName)) {
						const indices = new Array<number>();
						indices.push(i);
						shadowedVars.set(varName, indices);
					} else {
						shadowedVars.get(varName).push(i);
					}
				}
				for (const svIndices of shadowedVars.values()) {
					// sort by declared line number in descending order
					svIndices.sort((lhs: number, rhs: number) => {
						return vars[rhs].DeclLine - vars[lhs].DeclLine;
					});
					// enclose in parentheses, one pair per scope
					for (let scope = 0; scope < svIndices.length; ++scope) {
						const svIndex = svIndices[scope];
						// start at -1 so scope of 0 has one pair of parens
						for (let count = -1; count < scope; ++count) {
							vars[svIndex].name = `(${vars[svIndex].name})`;
						}
					}
				}
				const scopes = new Array<Scope>();
				const localVariables: DebugVariable = {
					name: 'Local',
					addr: 0,
					type: '',
					realType: '',
					kind: 0,
					flags: 0,
					onlyAddr: false,
					DeclLine: 0,
					value: '',
					len: 0,
					cap: 0,
					children: vars,
					unreadable: '',
					fullyQualifiedName: '',
					base: 0,
				};

				scopes.push(new Scope('Local', this.variableHandles.create(localVariables), false));
				response.body = { scopes };

				if (!this.showGlobalVariables) {
					this.sendResponse(response);
					log('ScopesResponse');
					return;
				}

				this.getPackageInfo(this.debugState).then(packageName => {
					if (!packageName) {
						this.sendResponse(response);
						log('ScopesResponse');
						return;
					}
					const filter = `^${packageName}\\.`;
					this.delve.call<DebugVariable[] | ListVarsOut>('ListPackageVars', this.delve.isApiV1 ? [filter] : [{ filter, cfg: this.delve.loadConfig }], (err, out) => {
						if (err) {
							logError('Failed to list global vars - ' + err.toString());
							return this.sendErrorResponse(response, 2007, 'Unable to list global vars: "{e}"', { e: err.toString() });
						}
						const globals = this.delve.isApiV1 ? <DebugVariable[]>out : (<ListVarsOut>out).Variables;
						let initdoneIndex = -1;
						for (let i = 0; i < globals.length; i++) {
							globals[i].name = globals[i].name.substr(packageName.length + 1);
							if (initdoneIndex === -1 && globals[i].name === this.initdone) {
								initdoneIndex = i;
							}
						}
						if (initdoneIndex > -1) {
							globals.splice(initdoneIndex, 1);
						}
						log('global vars', globals);

						const globalVariables: DebugVariable = {
							name: 'Global',
							addr: 0,
							type: '',
							realType: '',
							kind: 0,
							flags: 0,
							onlyAddr: false,
							DeclLine: 0,
							value: '',
							len: 0,
							cap: 0,
							children: globals,
							unreadable: '',
							fullyQualifiedName: '',
							base: 0,
						};
						scopes.push(new Scope('Global', this.variableHandles.create(globalVariables), false));
						this.sendResponse(response);
						log('ScopesResponse');
					});
				});
			});
		});
	}

	private getPackageInfo(debugState: DebuggerState): Thenable<string> {
		if (!debugState.currentThread || !debugState.currentThread.file) {
			return Promise.resolve(null);
		}
		const dir = path.dirname(this.delve.remotePath.length ? this.toLocalPath(debugState.currentThread.file) : debugState.currentThread.file);
		if (this.packageInfo.has(dir)) {
			return Promise.resolve(this.packageInfo.get(dir));
		}
		return new Promise(resolve => {
			execFile(getBinPathWithPreferredGopath('go', []), ['list', '-f', '{{.Name}} {{.ImportPath}}'], { cwd: dir, env: this.delve.dlvEnv }, (err, stdout, stderr) => {
				if (err || stderr || !stdout) {
					logError(`go list failed on ${dir}: ${stderr || err}`);
					return resolve();
				}
				if (stdout.split('\n').length !== 2) {
					logError(`Cannot determine package for ${dir}`);
					return resolve();
				}
				const spaceIndex = stdout.indexOf(' ');
				const result = stdout.substr(0, spaceIndex) === 'main' ? 'main' : stdout.substr(spaceIndex).trim();
				this.packageInfo.set(dir, result);
				resolve(result);
			});
		});
	}

	private convertDebugVariableToProtocolVariable(v: DebugVariable): { result: string; variablesReference: number; } {
		if (v.kind === GoReflectKind.UnsafePointer) {
			return {
				result: `unsafe.Pointer(0x${v.children[0].addr.toString(16)})`,
				variablesReference: 0
			};
		} else if (v.kind === GoReflectKind.Ptr) {
			if (v.children[0].addr === 0) {
				return {
					result: 'nil <' + v.type + '>',
					variablesReference: 0
				};
			} else if (v.children[0].type === 'void') {
				return {
					result: 'void',
					variablesReference: 0
				};
			} else {
				if (v.children[0].children.length > 0) {
					// Generate correct fullyQualified names for variable expressions
					v.children[0].fullyQualifiedName = v.fullyQualifiedName;
					v.children[0].children.forEach(child => {
						child.fullyQualifiedName = v.fullyQualifiedName + '.' + child.name;
					});
				}
				return {
					result: `<${v.type}>(0x${v.children[0].addr.toString(16)})`,
					variablesReference: v.children.length > 0 ? this.variableHandles.create(v) : 0
				};
			}
		} else if (v.kind === GoReflectKind.Slice) {
			if (v.base === 0) {
				return {
					result: 'nil <' + v.type + '>',
					variablesReference: 0
				};
			}
			return {
				result: '<' + v.type + '> (length: ' + v.len + ', cap: ' + v.cap + ')',
				variablesReference: this.variableHandles.create(v)
			};
		} else if (v.kind === GoReflectKind.Map) {
			if (v.base === 0) {
				return {
					result: 'nil <' + v.type + '>',
					variablesReference: 0
				};
			}
			return {
				result: '<' + v.type + '> (length: ' + v.len + ')',
				variablesReference: this.variableHandles.create(v)
			};
		} else if (v.kind === GoReflectKind.Array) {
			return {
				result: '<' + v.type + '>',
				variablesReference: this.variableHandles.create(v)
			};
		} else if (v.kind === GoReflectKind.String) {
			let val = v.value;
			const byteLength = Buffer.byteLength(val || '');
			if (v.value && byteLength < v.len) {
				val += `...+${v.len - byteLength} more`;
			}
			return {
				result: v.unreadable ? ('<' + v.unreadable + '>') : ('"' + val + '"'),
				variablesReference: 0
			};
		} else {
			// Default case - structs
			if (v.children.length > 0) {
				// Generate correct fullyQualified names for variable expressions
				v.children.forEach(child => {
					child.fullyQualifiedName = v.fullyQualifiedName + '.' + child.name;
				});
			}
			return {
				result: v.value || ('<' + v.type + '>'),
				variablesReference: v.children.length > 0 ? this.variableHandles.create(v) : 0
			};
		}
	}

	protected variablesRequest(response: DebugProtocol.VariablesResponse, args: DebugProtocol.VariablesArguments): void {
		log('VariablesRequest');
		const vari = this.variableHandles.get(args.variablesReference);
		let variablesPromise: Promise<DebugProtocol.Variable[]>;
		const loadChildren = async (exp: string, v: DebugVariable) => {
			// from https://github.com/go-delve/delve/blob/master/Documentation/api/ClientHowto.md#looking-into-variables
			if ((v.kind === GoReflectKind.Struct && v.len > v.children.length) ||
				(v.kind === GoReflectKind.Interface && v.children.length > 0 && v.children[0].onlyAddr === true)) {
				await this.evaluateRequestImpl({ 'expression': exp }).then(result => {
					const variable = this.delve.isApiV1 ? <DebugVariable>result : (<EvalOut>result).Variable;
					v.children = variable.children;
				}, err => logError('Failed to evaluate expression - ' + err.toString()));
			}
		};
		// expressions passed to loadChildren defined per https://github.com/go-delve/delve/blob/master/Documentation/api/ClientHowto.md#loading-more-of-a-variable
		if (vari.kind === GoReflectKind.Array || vari.kind === GoReflectKind.Slice) {
			variablesPromise = Promise.all(vari.children.map((v, i) => {
				return loadChildren(`*(*"${v.type}")(${v.addr})`, v).then((): DebugProtocol.Variable => {
					const { result, variablesReference } = this.convertDebugVariableToProtocolVariable(v);
					return {
						name: '[' + i + ']',
						value: result,
						evaluateName: vari.fullyQualifiedName + '[' + i + ']',
						variablesReference
					};
				});
			})
			);
		} else if (vari.kind === GoReflectKind.Map) {
			variablesPromise = Promise.all(vari.children.map((_, i) => {
				// even indices are map keys, odd indices are values
				if (i % 2 === 0 && i + 1 < vari.children.length) {
					const mapKey = this.convertDebugVariableToProtocolVariable(vari.children[i]);
					return loadChildren(`${vari.fullyQualifiedName}.${vari.name}[${mapKey.result}]`, vari.children[i + 1]).then(() => {
						const mapValue = this.convertDebugVariableToProtocolVariable(vari.children[i + 1]);
						return {
							name: mapKey.result,
							value: mapValue.result,
							evaluateName: vari.fullyQualifiedName + '[' + mapKey.result + ']',
							variablesReference: mapValue.variablesReference
						};
					});
				}
			}));
		} else {
			variablesPromise = Promise.all(vari.children.map((v) => {
				return loadChildren(`*(*"${v.type}")(${v.addr})`, v).then((): DebugProtocol.Variable => {
					const { result, variablesReference } = this.convertDebugVariableToProtocolVariable(v);

					return {
						name: v.name,
						value: result,
						evaluateName: v.fullyQualifiedName,
						variablesReference
					};
				});
			}));
		}
		variablesPromise.then((variables) => {
			response.body = { variables };
			this.sendResponse(response);
			log('VariablesResponse', JSON.stringify(variables, null, ' '));
		});
	}

	private cleanupHandles(): void {
		this.variableHandles.reset();
		this.stackFrameHandles.reset();
	}

	private handleReenterDebug(reason: string): void {
		this.cleanupHandles();

		if (this.debugState.exited) {
			this.sendEvent(new TerminatedEvent());
			log('TerminatedEvent');
		} else {
			// [TODO] Can we avoid doing this? https://github.com/Microsoft/vscode/issues/40#issuecomment-161999881
			this.delve.call<DebugGoroutine[] | ListGoroutinesOut>('ListGoroutines', [], (err, out) => {
				if (err) {
					logError('Failed to get threads - ' + err.toString());
				}
				const goroutines = this.delve.isApiV1 ? <DebugGoroutine[]>out : (<ListGoroutinesOut>out).Goroutines;
				this.updateGoroutinesList(goroutines);
				if (!this.debugState.currentGoroutine && goroutines.length > 0) {
					this.debugState.currentGoroutine = goroutines[0];
				}

				if (this.skipStopEventOnce) {
					this.skipStopEventOnce = false;
					return;
				}

				const stoppedEvent = new StoppedEvent(reason, this.debugState.currentGoroutine.id);
				(<any>stoppedEvent.body).allThreadsStopped = true;
				this.sendEvent(stoppedEvent);
				log('StoppedEvent("' + reason + '")');
			});
		}
	}

	private continueEpoch = 0;
	private continueRequestRunning = false;
	private continue(calledWhenSettingBreakpoint?: boolean): Thenable<void> {
		this.continueEpoch++;
		const closureEpoch = this.continueEpoch;
		this.continueRequestRunning = true;

		const callback = (out: any) => {
			if (closureEpoch === this.continueEpoch) {
				this.continueRequestRunning = false;
			}
			const state = this.delve.isApiV1 ? <DebuggerState>out : (<CommandOut>out).State;
			log('continue state', state);
			this.debugState = state;
			this.handleReenterDebug('breakpoint');
		};

		// If called when setting breakpoint internally, we want the error to bubble up.
		const errorCallback = calledWhenSettingBreakpoint ? null : (err: any) => {
			if (err) {
				logError('Failed to continue - ' + err.toString());
			}
			this.handleReenterDebug('breakpoint');
			throw err;
		};

		return this.delve.callPromise('Command', [{ name: 'continue' }]).then(callback, errorCallback);
	}

	protected continueRequest(response: DebugProtocol.ContinueResponse): void {
		log('ContinueRequest');
		this.continue();
		this.sendResponse(response);
		log('ContinueResponse');
	}

	protected nextRequest(response: DebugProtocol.NextResponse): void {
		log('NextRequest');
		this.delve.call<DebuggerState | CommandOut>('Command', [{ name: 'next' }], (err, out) => {
			if (err) {
				logError('Failed to next - ' + err.toString());
			}
			const state = this.delve.isApiV1 ? <DebuggerState>out : (<CommandOut>out).State;
			log('next state', state);
			this.debugState = state;
			this.handleReenterDebug('step');
		});
		this.sendResponse(response);
		log('NextResponse');
	}

	protected stepInRequest(response: DebugProtocol.StepInResponse): void {
		log('StepInRequest');
		this.delve.call<DebuggerState | CommandOut>('Command', [{ name: 'step' }], (err, out) => {
			if (err) {
				logError('Failed to step - ' + err.toString());
			}
			const state = this.delve.isApiV1 ? <DebuggerState>out : (<CommandOut>out).State;
			log('stop state', state);
			this.debugState = state;
			this.handleReenterDebug('step');
		});
		this.sendResponse(response);
		log('StepInResponse');
	}

	protected stepOutRequest(response: DebugProtocol.StepOutResponse): void {
		log('StepOutRequest');
		this.delve.call<DebuggerState | CommandOut>('Command', [{ name: 'stepOut' }], (err, out) => {
			if (err) {
				logError('Failed to stepout - ' + err.toString());
			}
			const state = this.delve.isApiV1 ? <DebuggerState>out : (<CommandOut>out).State;
			log('stepout state', state);
			this.debugState = state;
			this.handleReenterDebug('step');
		});
		this.sendResponse(response);
		log('StepOutResponse');
	}

	protected pauseRequest(response: DebugProtocol.PauseResponse): void {
		log('PauseRequest');
		this.delve.call<DebuggerState | CommandOut>('Command', [{ name: 'halt' }], (err, out) => {
			if (err) {
				logError('Failed to halt - ' + err.toString());
				return this.sendErrorResponse(response, 2010, 'Unable to halt execution: "{e}"', { e: err.toString() });
			}
			const state = this.delve.isApiV1 ? <DebuggerState>out : (<CommandOut>out).State;
			log('pause state', state);
			this.debugState = state;
			this.handleReenterDebug('pause');
		});
		this.sendResponse(response);
		log('PauseResponse');
	}

	protected evaluateRequest(response: DebugProtocol.EvaluateResponse, args: DebugProtocol.EvaluateArguments): void {
		log('EvaluateRequest');
		this.evaluateRequestImpl(args).then(out => {
			const variable = this.delve.isApiV1 ? <DebugVariable>out : (<EvalOut>out).Variable;
			// #2326: Set the fully qualified name for variable mapping
			variable.fullyQualifiedName = variable.name;
			response.body = this.convertDebugVariableToProtocolVariable(variable);
			this.sendResponse(response);
			log('EvaluateResponse');
		}, err => {
			this.sendErrorResponse(response, 2009, 'Unable to eval expression: "{e}"', { e: err.toString() });
		});
	}

	private evaluateRequestImpl(args: DebugProtocol.EvaluateArguments): Thenable<EvalOut | DebugVariable> {
		// default to the topmost stack frame of the current goroutine
		let goroutineId = -1;
		let frameId = 0;
		// args.frameId won't be specified when evaluating global vars
		if (args.frameId) {
			[goroutineId, frameId] = this.stackFrameHandles.get(args.frameId);
		}
		const scope = {
			goroutineID: goroutineId,
			frame: frameId
		};
		const evalSymbolArgs = this.delve.isApiV1 ? {
			symbol: args.expression,
			scope
		} : {
				Expr: args.expression,
				Scope: scope,
				Cfg: this.delve.loadConfig
			};
		const returnValue = this.delve.callPromise<EvalOut | DebugVariable>(this.delve.isApiV1 ? 'EvalSymbol' : 'Eval', [evalSymbolArgs]).then(val => val,
			err => {
				logError('Failed to eval expression: ', JSON.stringify(evalSymbolArgs, null, ' '), '\n\rEval error:', err.toString());
				return Promise.reject(err);
			});
		return returnValue;
	}

	protected setVariableRequest(response: DebugProtocol.SetVariableResponse, args: DebugProtocol.SetVariableArguments): void {
		log('SetVariableRequest');
		const scope = {
			goroutineID: this.debugState.currentGoroutine.id
		};
		const setSymbolArgs = {
			Scope: scope,
			Symbol: args.name,
			Value: args.value
		};
		this.delve.call(this.delve.isApiV1 ? 'SetSymbol' : 'Set', [setSymbolArgs], (err) => {
			if (err) {
				const errMessage = `Failed to set variable: ${err.toString()}`;
				logError(errMessage);
				return this.sendErrorResponse(response, 2010, errMessage);
			}
			response.body = { value: args.value };
			this.sendResponse(response);
			log('SetVariableResponse');
		});
	}

	private addFullyQualifiedName(variables: DebugVariable[]) {
		variables.forEach(local => {
			local.fullyQualifiedName = local.name;
			local.children.forEach(child => {
				child.fullyQualifiedName = local.name;
			});
		});
	}
}

function random(low: number, high: number): number {
	return Math.floor(Math.random() * (high - low) + low);
}

function killTree(processId: number): void {
	if (process.platform === 'win32') {
		const TASK_KILL = 'C:\\Windows\\System32\\taskkill.exe';

		// when killing a process in Windows its child processes are *not* killed but become root processes.
		// Therefore we use TASKKILL.EXE
		try {
			execSync(`${TASK_KILL} /F /T /PID ${processId}`);
		} catch (err) {
			logError(`Error killing process tree: ${err.toString() || ''}`);
		}
	} else {
		// on linux and OS X we kill all direct and indirect child processes as well
		try {
			const cmd = path.join(__dirname, '../../../scripts/terminateProcess.sh');
			spawnSync(cmd, [processId.toString()]);
		} catch (err) {
			logError(`Error killing process tree: ${err.toString() || ''}`);
		}
	}
}

async function removeFile(filePath: string): Promise<void> {
	try {
		const fileExists = await fsAccess(filePath)
			.then(() => true)
			.catch(() => false);
		if (filePath && fileExists) {
			await fsUnlink(filePath);
		}
	} catch (e) {
		logError(`Potentially failed remove file: ${filePath} - ${e.toString() || ''}`);
	}
}

DebugSession.run(GoDebugSession);