Check exit code

[fpoli]

The Viper IDE took its spawn function from this repository. In the process, they did some nice changes, among with a check of the exist code of the spawned process: viperproject/viper-ide#357. We should port the same check to this repository.

Relevant code:

prusti-assistant/src/util.ts

Lines 95 to 188 in 694dc6c

	export function spawn(
	cmd: string,
	args?: string[] | undefined,
	{ options, onStdout, onStderr }: {
	options?: childProcess.SpawnOptionsWithoutStdio;
	onStdout?: ((data: string) => void);
	onStderr?: ((data: string) => void);
	} = {},
	destructors?: Set<KillFunction>,
	): Promise<Output> {
	const description = `${cmd} ${args?.join(" ") ?? ""}`;
	log(`Run command '${description}'`);
	let stdout = "";
	let stderr = "";
	const start = process.hrtime();
	const proc = childProcess.spawn(cmd, args, options);
	const status: { killed: boolean } = { killed: false };
	log(`Spawned PID: ${proc.pid}`);
	// Register destructor
	function killProc() {
	if (!status.killed) {
	status.killed = true;
	// TODO: Try with SIGTERM before.
	treeKill(proc.pid, "SIGKILL", (err) => {
	if (err) {
	log(`Failed to kill process tree of ${proc.pid}: ${err}`);
	const succeeded = proc.kill("SIGKILL");
	if (!succeeded) {
	log(`Failed to kill process ${proc}.`);
	}
	} else {
	log(`Process ${proc.pid} has been killed successfully.`);
	}
	});
	} else {
	log(`Process ${proc.pid} has already been killed.`);
	}
	}
	if (destructors) {
	destructors.add(killProc);
	}
	proc.stdout.on("data", (data) => {
	stdout += data;
	try {
	onStdout?.(data);
	} catch (e) {
	log(`error in stdout handler for '${description}': ${e}`);
	}
	});
	proc.stderr.on("data", (data) => {
	stderr += data;
	try {
	onStderr?.(data);
	} catch (e) {
	log(`error in stderr handler for '${description}': ${e}`);
	}
	});
	function printOutput(duration: Duration, code: number | null, signal: NodeJS.Signals | null) {
	const durationSecMsg = (duration[0] + duration[1] / 1e9).toFixed(1);
	log(`Output from '${description}' (${durationSecMsg}s):`);
	log("┌──── Begin stdout ────┐");
	log(stdout);
	log("└──── End stdout ──────┘");
	log("┌──── Begin stderr ────┐");
	log(stderr);
	log("└──── End stderr ──────┘");
	log(`Exit code ${code}, signal ${signal}.`);
	}
	return new Promise((resolve, reject) => {
	proc.on("close", (code, signal) => {
	const duration = process.hrtime(start);
	printOutput(duration, code, signal);
	if (destructors) {
	destructors.delete(killProc);
	}
	resolve({ stdout, stderr, code, signal, duration });
	});
	proc.on("error", (err) => {
	const duration = process.hrtime(start);
	printOutput(duration, null, null);
	log(`Error: ${err}`);
	if (destructors) {
	destructors.delete(killProc);
	}
	reject(err);
	});
	});
	}