ed-syntax
      if (match) throw new Error(match[1]);
      out = macCppfiltNm(out);
    }
    return out;
  },
};
const print = console.log;
function read(fileName) {
  return fs.readFileSync(fileName, 'utf8');
}
const quit = process.exit;
// Polyfill "readline()".
const logFile = globalThis.arguments[globalThis.arguments.length - 1];
try {
  fs.accessSync(logFile);
} catch {
  console.error('Please provide a valid isolate file as the final argument.');
  process.exit(1);
}
const fd = fs.openSync(logFile, 'r');
const buf = Buffer.allocUnsafe(4096);
const dec = new (require('string_decoder').StringDecoder)('utf-8');
let line = '';

{
  const message = versionCheck(peekline(), process.versions.v8);
  if (message) console.log(message);
}

function peekline() {
  const s = readline();
  line = `${s}\n${line}`;
  return s;
}

function readline() {
  while (true) {
    const lineBreak = line.indexOf('\n');
    if (lineBreak !== -1) {
      const res = line.slice(0, lineBreak);
      line = line.slice(lineBreak + 1);
      return res;
    }
    const bytes = fs.readSync(fd, buf, 0, buf.length);
    line += dec.write(buf.slice(0, bytes));
    if (line.length === 0) {
      return '';
    }
    if (bytes === 0) {
      process.emitWarning(`Profile file ${logFile} is broken`, {
        code: 'BROKEN_PROFILE_FILE',
        detail: `${JSON.stringify(line)} at the file end is broken`,
      });
      return '';
    }
  }
}

function versionCheck(firstLine, expected) {
  // v8-version looks like
  // "v8-version,$major,$minor,$build,$patch[,$embedder],$candidate"
  // whereas process.versions.v8 is either "$major.$minor.$build-$embedder" or
  // "$major.$minor.$build.$patch-$embedder".
  firstLine = firstLine.split(',');
  const curVer = expected.split(/[.-]/);
  if ((firstLine.length !== 6 && firstLine.length !== 7) ||
      firstLine[0] !== 'v8-version') {
    return 'Unable to read v8-version from log file.';
  }
  // Compare major, minor and build; ignore the patch and candidate fields.
  for (let i = 0; i < 3; i++)
    if (curVer[i] !== firstLine[i + 1])
      return 'Testing v8 version different from logging version';
}

function macCppfiltNm(out) {
  // Re-grouped copy-paste from `tickprocessor.js`
  const FUNC_RE = /^([0-9a-fA-F]{8,16} [iItT] )(.*)$/gm;
  const CLEAN_RE = /^[0-9a-fA-F]{8,16} [iItT] /;
  let entries = out.match(FUNC_RE);
  if (entries === null)
    return out;

  entries = entries.map((entry) => entry.replace(CLEAN_RE, ''));

  let filtered;
  try {
    filtered = cp.spawnSync('c++filt', [ '-p', '-i' ], {
      input: entries.join('\n'),
    }).stdout.toString();
  } catch {
    return out;
  }

  let i = 0;
  filtered = filtered.split('\n');
  return out.replace(FUNC_RE, (all, prefix, postfix) => {
    return prefix + (filtered[i++] || postfix);
  });
}

Object.assign(globalThis, {
  os,
  print,
  read,
  quit,
  readline,
});
