node/lib/util.js

'use strict';

const uv = process.binding('uv');
const Buffer = require('buffer').Buffer;
const internalUtil = require('internal/util');
const binding = process.binding('util');

const isError = internalUtil.isError;

var Debug;

const formatRegExp = /%[sdj%]/g;
exports.format = function(f) {
  if (typeof f !== 'string') {
    var objects = [];
    for (var index = 0; index < arguments.length; index++) {
      objects.push(inspect(arguments[index]));
    }
    return objects.join(' ');
  }

  if (arguments.length === 1) return f;

  var i = 1;
  var args = arguments;
  var len = args.length;
  var str = String(f).replace(formatRegExp, function(x) {
    if (x === '%%') return '%';
    if (i >= len) return x;
    switch (x) {
      case '%s': return String(args[i++]);
      case '%d': return Number(args[i++]);
      case '%j':
        try {
          return JSON.stringify(args[i++]);
        } catch (_) {
          return '[Circular]';
        }
        // falls through
      default:
        return x;
    }
  });
  for (var x = args[i]; i < len; x = args[++i]) {
    if (x === null || (typeof x !== 'object' && typeof x !== 'symbol')) {
      str += ' ' + x;
    } else {
      str += ' ' + inspect(x);
    }
  }
  return str;
};


exports.deprecate = internalUtil._deprecate;


var debugs = {};
var debugEnviron;
exports.debuglog = function(set) {
  if (debugEnviron === undefined)
    debugEnviron = process.env.NODE_DEBUG || '';
  set = set.toUpperCase();
  if (!debugs[set]) {
    if (new RegExp('\\b' + set + '\\b', 'i').test(debugEnviron)) {
      var pid = process.pid;
      debugs[set] = function() {
        var msg = exports.format.apply(exports, arguments);
        console.error('%s %d: %s', set, pid, msg);
      };
    } else {
      debugs[set] = function() {};
    }
  }
  return debugs[set];
};


/**
 * Echos the value of a value. Tries to print the value out
 * in the best way possible given the different types.
 *
 * @param {Object} obj The object to print out.
 * @param {Object} opts Optional options object that alters the output.
 */
/* legacy: obj, showHidden, depth, colors*/
function inspect(obj, opts) {
  // default options
  var ctx = {
    seen: [],
    stylize: stylizeNoColor
  };
  // legacy...
  if (arguments.length >= 3) ctx.depth = arguments[2];
  if (arguments.length >= 4) ctx.colors = arguments[3];
  if (typeof opts === 'boolean') {
    // legacy...
    ctx.showHidden = opts;
  } else if (opts) {
    // got an "options" object
    exports._extend(ctx, opts);
  }
  // set default options
  if (ctx.showHidden === undefined) ctx.showHidden = false;
  if (ctx.depth === undefined) ctx.depth = 2;
  if (ctx.colors === undefined) ctx.colors = false;
  if (ctx.customInspect === undefined) ctx.customInspect = true;
  if (ctx.colors) ctx.stylize = stylizeWithColor;
  return formatValue(ctx, obj, ctx.depth);
}
exports.inspect = inspect;


// http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
inspect.colors = {
  'bold' : [1, 22],
  'italic' : [3, 23],
  'underline' : [4, 24],
  'inverse' : [7, 27],
  'white' : [37, 39],
  'grey' : [90, 39],
  'black' : [30, 39],
  'blue' : [34, 39],
  'cyan' : [36, 39],
  'green' : [32, 39],
  'magenta' : [35, 39],
  'red' : [31, 39],
  'yellow' : [33, 39]
};

// Don't use 'blue' not visible on cmd.exe
inspect.styles = {
  'special': 'cyan',
  'number': 'yellow',
  'boolean': 'yellow',
  'undefined': 'grey',
  'null': 'bold',
  'string': 'green',
  'symbol': 'green',
  'date': 'magenta',
  // "name": intentionally not styling
  'regexp': 'red'
};


function stylizeWithColor(str, styleType) {
  var style = inspect.styles[styleType];

  if (style) {
    return '\u001b[' + inspect.colors[style][0] + 'm' + str +
           '\u001b[' + inspect.colors[style][1] + 'm';
  } else {
    return str;
  }
}


function stylizeNoColor(str, styleType) {
  return str;
}


function arrayToHash(array) {
  var hash = Object.create(null);

  for (var i = 0; i < array.length; i++) {
    var val = array[i];
    hash[val] = true;
  }

  return hash;
}


function getConstructorOf(obj) {
  while (obj) {
    var descriptor = Object.getOwnPropertyDescriptor(obj, 'constructor');
    if (descriptor !== undefined &&
        typeof descriptor.value === 'function' &&
        descriptor.value.name !== '') {
      return descriptor.value;
    }

    obj = Object.getPrototypeOf(obj);
  }

  return null;
}


function ensureDebugIsInitialized() {
  if (Debug === undefined) {
    const runInDebugContext = require('vm').runInDebugContext;
    Debug = runInDebugContext('Debug');
  }
}


function inspectPromise(p) {
  ensureDebugIsInitialized();
  // Only create a mirror if the object is a Promise.
  if (!binding.isPromise(p))
    return null;
  const mirror = Debug.MakeMirror(p, true);
  return {status: mirror.status(), value: mirror.promiseValue().value_};
}


function formatValue(ctx, value, recurseTimes) {
  // Provide a hook for user-specified inspect functions.
  // Check that value is an object with an inspect function on it
  if (ctx.customInspect &&
      value &&
      typeof value.inspect === 'function' &&
      // Filter out the util module, it's inspect function is special
      value.inspect !== exports.inspect &&
      // Also filter out any prototype objects using the circular check.
      !(value.constructor && value.constructor.prototype === value)) {
    var ret = value.inspect(recurseTimes, ctx);
    if (typeof ret !== 'string') {
      ret = formatValue(ctx, ret, recurseTimes);
    }
    return ret;
  }

  // Primitive types cannot have properties
  var primitive = formatPrimitive(ctx, value);
  if (primitive) {
    return primitive;
  }

  // Look up the keys of the object.
  var keys = Object.keys(value);
  var visibleKeys = arrayToHash(keys);

  if (ctx.showHidden) {
    keys = Object.getOwnPropertyNames(value);
    keys = keys.concat(Object.getOwnPropertySymbols(value));
  }

  // This could be a boxed primitive (new String(), etc.), check valueOf()
  // NOTE: Avoid calling `valueOf` on `Date` instance because it will return
  // a number which, when object has some additional user-stored `keys`,
  // will be printed out.
  var formatted;
  var raw = value;
  try {
    // the .valueOf() call can fail for a multitude of reasons
    if (!isDate(value))
      raw = value.valueOf();
  } catch (e) {
    // ignore...
  }

  if (typeof raw === 'string') {
    // for boxed Strings, we have to remove the 0-n indexed entries,
    // since they just noisy up the output and are redundant
    keys = keys.filter(function(key) {
      return !(key >= 0 && key < raw.length);
    });
  }

  // Some type of object without properties can be shortcutted.
  if (keys.length === 0) {
    if (typeof value === 'function') {
      var name = value.name ? ': ' + value.name : '';
      return ctx.stylize('[Function' + name + ']', 'special');
    }
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    }
    if (isDate(value)) {
      return ctx.stylize(Date.prototype.toISOString.call(value), 'date');
    }
    if (isError(value)) {
      return formatError(value);
    }
    // now check the `raw` value to handle boxed primitives
    if (typeof raw === 'string') {
      formatted = formatPrimitiveNoColor(ctx, raw);
      return ctx.stylize('[String: ' + formatted + ']', 'string');
    }
    if (typeof raw === 'number') {
      formatted = formatPrimitiveNoColor(ctx, raw);
      return ctx.stylize('[Number: ' + formatted + ']', 'number');
    }
    if (typeof raw === 'boolean') {
      formatted = formatPrimitiveNoColor(ctx, raw);
      return ctx.stylize('[Boolean: ' + formatted + ']', 'boolean');
    }
    // Fast path for ArrayBuffer.  Can't do the same for DataView because it
    // has a non-primitive .buffer property that we need to recurse for.
    if (binding.isArrayBuffer(value)) {
      return `${getConstructorOf(value).name}` +
             ` { byteLength: ${formatNumber(ctx, value.byteLength)} }`;
    }
  }

  var constructor = getConstructorOf(value);
  var base = '', empty = false, braces;
  var formatter = formatObject;

  // We can't compare constructors for various objects using a comparison like
  // `constructor === Array` because the object could have come from a different
  // context and thus the constructor won't match. Instead we check the
  // constructor names (including those up the prototype chain where needed) to
  // determine object types.
  if (Array.isArray(value)) {
    // Unset the constructor to prevent "Array [...]" for ordinary arrays.
    if (constructor && constructor.name === 'Array')
      constructor = null;
    braces = ['[', ']'];
    empty = value.length === 0;
    formatter = formatArray;
  } else if (binding.isSet(value)) {
    braces = ['{', '}'];
    // With `showHidden`, `length` will display as a hidden property for
    // arrays. For consistency's sake, do the same for `size`, even though this
    // property isn't selected by Object.getOwnPropertyNames().
    if (ctx.showHidden)
      keys.unshift('size');
    empty = value.size === 0;
    formatter = formatSet;
  } else if (binding.isMap(value)) {
    braces = ['{', '}'];
    // Ditto.
    if (ctx.showHidden)
      keys.unshift('size');
    empty = value.size === 0;
    formatter = formatMap;
  } else if (binding.isArrayBuffer(value)) {
    braces = ['{', '}'];
    keys.unshift('byteLength');
    visibleKeys.byteLength = true;
  } else if (binding.isDataView(value)) {
    braces = ['{', '}'];
    // .buffer goes last, it's not a primitive like the others.
    keys.unshift('byteLength', 'byteOffset', 'buffer');
    visibleKeys.byteLength = true;
    visibleKeys.byteOffset = true;
    visibleKeys.buffer = true;
  } else if (binding.isTypedArray(value)) {
    braces = ['[', ']'];
    formatter = formatTypedArray;
    if (ctx.showHidden) {
      // .buffer goes last, it's not a primitive like the others.
      keys.unshift('BYTES_PER_ELEMENT',
                   'length',
                   'byteLength',
                   'byteOffset',
                   'buffer');
    }
  } else {
    var promiseInternals = inspectPromise(value);
    if (promiseInternals) {
      braces = ['{', '}'];
      formatter = formatPromise;
    } else {
      if (binding.isMapIterator(value)) {
        constructor = { name: 'MapIterator' };
        braces = ['{', '}'];
        empty = false;
        formatter = formatCollectionIterator;
      } else if (binding.isSetIterator(value)) {
        constructor = { name: 'SetIterator' };
        braces = ['{', '}'];
        empty = false;
        formatter = formatCollectionIterator;
      } else {
        // Unset the constructor to prevent "Object {...}" for ordinary objects.
        if (constructor && constructor.name === 'Object')
          constructor = null;
        braces = ['{', '}'];
        empty = true;  // No other data than keys.
      }
    }
  }

  empty = empty === true && keys.length === 0;

  // Make functions say that they are functions
  if (typeof value === 'function') {
    var n = value.name ? ': ' + value.name : '';
    base = ' [Function' + n + ']';
  }

  // Make RegExps say that they are RegExps
  if (isRegExp(value)) {
    base = ' ' + RegExp.prototype.toString.call(value);
  }

  // Make dates with properties first say the date
  if (isDate(value)) {
    base = ' ' + Date.prototype.toISOString.call(value);
  }

  // Make error with message first say the error
  if (isError(value)) {
    base = ' ' + formatError(value);
  }

  // Make boxed primitive Strings look like such
  if (typeof raw === 'string') {
    formatted = formatPrimitiveNoColor(ctx, raw);
    base = ' ' + '[String: ' + formatted + ']';
  }

  // Make boxed primitive Numbers look like such
  if (typeof raw === 'number') {
    formatted = formatPrimitiveNoColor(ctx, raw);
    base = ' ' + '[Number: ' + formatted + ']';
  }

  // Make boxed primitive Booleans look like such
  if (typeof raw === 'boolean') {
    formatted = formatPrimitiveNoColor(ctx, raw);
    base = ' ' + '[Boolean: ' + formatted + ']';
  }

  // Add constructor name if available
  if (base === '' && constructor)
    braces[0] = constructor.name + ' ' + braces[0];

  if (empty === true) {
    return braces[0] + base + braces[1];
  }

  if (recurseTimes < 0) {
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    } else {
      return ctx.stylize('[Object]', 'special');
    }
  }

  ctx.seen.push(value);

  var output = formatter(ctx, value, recurseTimes, visibleKeys, keys);

  ctx.seen.pop();

  return reduceToSingleString(output, base, braces);
}


function formatNumber(ctx, value) {
  // Format -0 as '-0'. Strict equality won't distinguish 0 from -0,
  // so instead we use the fact that 1 / -0 < 0 whereas 1 / 0 > 0 .
  if (value === 0 && 1 / value < 0)
    return ctx.stylize('-0', 'number');
  return ctx.stylize('' + value, 'number');
}


function formatPrimitive(ctx, value) {
  if (value === undefined)
    return ctx.stylize('undefined', 'undefined');

  // For some reason typeof null is "object", so special case here.
  if (value === null)
    return ctx.stylize('null', 'null');

  var type = typeof value;

  if (type === 'string') {
    var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
        .replace(/'/g, "\\'")
        .replace(/\\"/g, '"') + '\'';
    return ctx.stylize(simple, 'string');
  }
  if (type === 'number')
    return formatNumber(ctx, value);
  if (type === 'boolean')
    return ctx.stylize('' + value, 'boolean');
  // es6 symbol primitive
  if (type === 'symbol')
    return ctx.stylize(value.toString(), 'symbol');
}


function formatPrimitiveNoColor(ctx, value) {
  var stylize = ctx.stylize;
  ctx.stylize = stylizeNoColor;
  var str = formatPrimitive(ctx, value);
  ctx.stylize = stylize;
  return str;
}


function formatError(value) {
  return value.stack || '[' + Error.prototype.toString.call(value) + ']';
}


function formatObject(ctx, value, recurseTimes, visibleKeys, keys) {
  return keys.map(function(key) {
    return formatProperty(ctx, value, recurseTimes, visibleKeys, key, false);
  });
}


function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  for (var i = 0, l = value.length; i < l; ++i) {
    if (hasOwnProperty(value, String(i))) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          String(i), true));
    } else {
      output.push('');
    }
  }
  keys.forEach(function(key) {
    if (typeof key === 'symbol' || !key.match(/^\d+$/)) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          key, true));
    }
  });
  return output;
}


function formatTypedArray(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = new Array(value.length);
  for (var i = 0, l = value.length; i < l; ++i)
    output[i] = formatNumber(ctx, value[i]);
  for (const key of keys) {
    if (typeof key === 'symbol' || !key.match(/^\d+$/)) {
      output.push(
          formatProperty(ctx, value, recurseTimes, visibleKeys, key, true));
    }
  }
  return output;
}


function formatSet(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  value.forEach(function(v) {
    var nextRecurseTimes = recurseTimes === null ? null : recurseTimes - 1;
    var str = formatValue(ctx, v, nextRecurseTimes);
    output.push(str);
  });
  keys.forEach(function(key) {
    output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
                               key, false));
  });
  return output;
}


function formatMap(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  value.forEach(function(v, k) {
    var nextRecurseTimes = recurseTimes === null ? null : recurseTimes - 1;
    var str = formatValue(ctx, k, nextRecurseTimes);
    str += ' => ';
    str += formatValue(ctx, v, nextRecurseTimes);
    output.push(str);
  });
  keys.forEach(function(key) {
    output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
                               key, false));
  });
  return output;
}

function formatCollectionIterator(ctx, value, recurseTimes, visibleKeys, keys) {
  ensureDebugIsInitialized();
  const mirror = Debug.MakeMirror(value, true);
  var nextRecurseTimes = recurseTimes === null ? null : recurseTimes - 1;
  var vals = mirror.preview();
  var output = [];
  for (const o of vals) {
    output.push(formatValue(ctx, o, nextRecurseTimes));
  }
  return output;
}

function formatPromise(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  var internals = inspectPromise(value);
  if (internals.status === 'pending') {
    output.push('<pending>');
  } else {
    var nextRecurseTimes = recurseTimes === null ? null : recurseTimes - 1;
    var str = formatValue(ctx, internals.value, nextRecurseTimes);
    if (internals.status === 'rejected') {
      output.push('<rejected> ' + str);
    } else {
      output.push(str);
    }
  }
  keys.forEach(function(key) {
    output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
                               key, false));
  });
  return output;
}


function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
  var name, str, desc;
  desc = Object.getOwnPropertyDescriptor(value, key) || { value: value[key] };
  if (desc.get) {
    if (desc.set) {
      str = ctx.stylize('[Getter/Setter]', 'special');
    } else {
      str = ctx.stylize('[Getter]', 'special');
    }
  } else {
    if (desc.set) {
      str = ctx.stylize('[Setter]', 'special');
    }
  }
  if (!hasOwnProperty(visibleKeys, key)) {
    if (typeof key === 'symbol') {
      name = '[' + ctx.stylize(key.toString(), 'symbol') + ']';
    } else {
      name = '[' + key + ']';
    }
  }
  if (!str) {
    if (ctx.seen.indexOf(desc.value) < 0) {
      if (recurseTimes === null) {
        str = formatValue(ctx, desc.value, null);
      } else {
        str = formatValue(ctx, desc.value, recurseTimes - 1);
      }
      if (str.indexOf('\n') > -1) {
        if (array) {
          str = str.replace(/\n/g, '\n  ');
        } else {
          str = str.replace(/(^|\n)/g, '\n   ');
        }
      }
    } else {
      str = ctx.stylize('[Circular]', 'special');
    }
  }
  if (name === undefined) {
    if (array && key.match(/^\d+$/)) {
      return str;
    }
    name = JSON.stringify('' + key);
    if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
      name = name.substr(1, name.length - 2);
      name = ctx.stylize(name, 'name');
    } else {
      name = name.replace(/'/g, "\\'")
                 .replace(/\\"/g, '"')
                 .replace(/(^"|"$)/g, "'")
                 .replace(/\\\\/g, '\\');
      name = ctx.stylize(name, 'string');
    }
  }

  return name + ': ' + str;
}


function reduceToSingleString(output, base, braces) {
  var length = output.reduce(function(prev, cur) {
    return prev + cur.replace(/\u001b\[\d\d?m/g, '').length + 1;
  }, 0);

  if (length > 60) {
    return braces[0] +
           // If the opening "brace" is too large, like in the case of "Set {",
           // we need to force the first item to be on the next line or the
           // items will not line up correctly.
           (base === '' && braces[0].length === 1 ? '' : base + '\n ') +
           ' ' +
           output.join(',\n  ') +
           ' ' +
           braces[1];
  }

  return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
}


// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.
exports.isArray = Array.isArray;

function isBoolean(arg) {
  return typeof arg === 'boolean';
}
exports.isBoolean = isBoolean;

function isNull(arg) {
  return arg === null;
}
exports.isNull = isNull;

function isNullOrUndefined(arg) {
  return arg === null || arg === undefined;
}
exports.isNullOrUndefined = isNullOrUndefined;

function isNumber(arg) {
  return typeof arg === 'number';
}
exports.isNumber = isNumber;

function isString(arg) {
  return typeof arg === 'string';
}
exports.isString = isString;

function isSymbol(arg) {
  return typeof arg === 'symbol';
}
exports.isSymbol = isSymbol;

function isUndefined(arg) {
  return arg === undefined;
}
exports.isUndefined = isUndefined;

function isRegExp(re) {
  return binding.isRegExp(re);
}
exports.isRegExp = isRegExp;

function isObject(arg) {
  return arg !== null && typeof arg === 'object';
}
exports.isObject = isObject;

function isDate(d) {
  return binding.isDate(d);
}
exports.isDate = isDate;

exports.isError = isError;

function isFunction(arg) {
  return typeof arg === 'function';
}
exports.isFunction = isFunction;

function isPrimitive(arg) {
  return arg === null ||
         typeof arg !== 'object' && typeof arg !== 'function';
}
exports.isPrimitive = isPrimitive;

exports.isBuffer = Buffer.isBuffer;


function pad(n) {
  return n < 10 ? '0' + n.toString(10) : n.toString(10);
}


const months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep',
                'Oct', 'Nov', 'Dec'];

// 26 Feb 16:19:34
function timestamp() {
  var d = new Date();
  var time = [pad(d.getHours()),
              pad(d.getMinutes()),
              pad(d.getSeconds())].join(':');
  return [d.getDate(), months[d.getMonth()], time].join(' ');
}


// log is just a thin wrapper to console.log that prepends a timestamp
exports.log = function() {
  console.log('%s - %s', timestamp(), exports.format.apply(exports, arguments));
};


/**
 * Inherit the prototype methods from one constructor into another.
 *
 * The Function.prototype.inherits from lang.js rewritten as a standalone
 * function (not on Function.prototype). NOTE: If this file is to be loaded
 * during bootstrapping this function needs to be rewritten using some native
 * functions as prototype setup using normal JavaScript does not work as
 * expected during bootstrapping (see mirror.js in r114903).
 *
 * @param {function} ctor Constructor function which needs to inherit the
 *     prototype.
 * @param {function} superCtor Constructor function to inherit prototype from.
 * @throws {TypeError} Will error if either constructor is null, or if
 *     the super constructor lacks a prototype.
 */
exports.inherits = function(ctor, superCtor) {

  if (ctor === undefined || ctor === null)
    throw new TypeError('The constructor to "inherits" must not be ' +
                        'null or undefined');

  if (superCtor === undefined || superCtor === null)
    throw new TypeError('The super constructor to "inherits" must not ' +
                        'be null or undefined');

  if (superCtor.prototype === undefined)
    throw new TypeError('The super constructor to "inherits" must ' +
                        'have a prototype');

  ctor.super_ = superCtor;
  Object.setPrototypeOf(ctor.prototype, superCtor.prototype);
};

exports._extend = function(origin, add) {
  // Don't do anything if add isn't an object
  if (add === null || typeof add !== 'object') return origin;

  var keys = Object.keys(add);
  var i = keys.length;
  while (i--) {
    origin[keys[i]] = add[keys[i]];
  }
  return origin;
};

function hasOwnProperty(obj, prop) {
  return Object.prototype.hasOwnProperty.call(obj, prop);
}


// Deprecated old stuff.

exports.print = internalUtil.deprecate(function() {
  for (var i = 0, len = arguments.length; i < len; ++i) {
    process.stdout.write(String(arguments[i]));
  }
}, 'util.print is deprecated. Use console.log instead.');


exports.puts = internalUtil.deprecate(function() {
  for (var i = 0, len = arguments.length; i < len; ++i) {
    process.stdout.write(arguments[i] + '\n');
  }
}, 'util.puts is deprecated. Use console.log instead.');


exports.debug = internalUtil.deprecate(function(x) {
  process.stderr.write('DEBUG: ' + x + '\n');
}, 'util.debug is deprecated. Use console.error instead.');


exports.error = internalUtil.deprecate(function(x) {
  for (var i = 0, len = arguments.length; i < len; ++i) {
    process.stderr.write(arguments[i] + '\n');
  }
}, 'util.error is deprecated. Use console.error instead.');


exports._errnoException = function(err, syscall, original) {
  var errname = uv.errname(err);
  var message = syscall + ' ' + errname;
  if (original)
    message += ' ' + original;
  var e = new Error(message);
  e.code = errname;
  e.errno = errname;
  e.syscall = syscall;
  return e;
};


exports._exceptionWithHostPort = function(err,
                                          syscall,
                                          address,
                                          port,
                                          additional) {
  var details;
  if (port && port > 0) {
    details = address + ':' + port;
  } else {
    details = address;
  }

  if (additional) {
    details += ' - Local (' + additional + ')';
  }
  var ex = exports._errnoException(err, syscall, details);
  ex.address = address;
  if (port) {
    ex.port = port;
  }
  return ex;
};