@seadub/clang-format-lint/index.js

Validate and/or fix formatting of files via clang-format

#!/usr/bin/env node
'use strict';

const clangFormat = require('clang-format');
const pLimit = require('p-limit');

/**
 * 
 * @param {string} filepath 
 * @param {boolean} fix
 * @returns {Promise<undefined|Error>} 
 */
function lintFile(filepath, fix) {
	return new Promise((resolve, reject) => {
		let stdout = '';
		const args = [ '-style=file' ];
		if (fix) {
			args.push('-i');
		} else {
			args.push('-output-replacements-xml');
		}
		args.push(filepath);

		const proc = clangFormat.spawnClangFormat(args, () => {}, 'pipe');
		proc.stdout.on('data', function (data) {
			stdout += data.toString();
		});
		proc.on('close', function (exit) {
			if (exit) {
				// Should we be rejecting if the exit code is non-zero? It'll stop processing *all* files
				return reject(new Error(`Failed to execute clang-format on ${filepath}. Exit code: ${exit}`));
			}

			if (fix) {
				return resolve();
			}

			// doing validation...
			const modified = stdout.replace(/\r?\n/g, '');
			if (modified !== '<?xml version=\'1.0\'?><replacements xml:space=\'preserve\' incomplete_format=\'false\'></replacements>') {
				// Record failure, because formatting is bad.
				// TODO Get the correctly formatted source? Give more details on the bad sections?
				// Instead of rejecting, resolve with the error - so we ensure every file gets processed!
				resolve(new Error(`Formatting incorrect on "${filepath}", proposed changes: ${stdout}`));
			}
			resolve();
		});
	});
}

/**
 * @param {string[]} files list of filepaths to validate/fix
 * @param {integer} execLimit maximum number of files to process simultaneously
 * @param {boolean} [fix=false] automatically fix the files?
 * @throws {Error} if any files failed validation
 */
async function main(files, execLimit, fix = false) {
	const limit = pLimit(execLimit);

	const promises = files.map(file => limit(lintFile, file, fix));
	const results = await Promise.all(promises);

	// filter results to ones containing Error instances
	const errors = results.filter(r => r instanceof Error);
	if (errors.length > 0) {
		const error = new Error(errors.join('\n'));
		error.code = 'ELINTFAILURE';
		throw error;
	}
}

module.exports = main;