fs: deprecate fs.read's string interface

`fs.read` supports a deprecated string interface version, which is not documented. It was intended to be deprecated in this commit in 2010 c93e0aa This patch issues a deprecation message saying the usage of this interface is deprecated. PR-URL: #4525 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Trevor Norris <trev.norris@gmail.com> Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com> Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

Author: thefourtheye

lib/fs.js

@@ -35,6 +35,7 @@ const isWindows = process.platform === 'win32';
 
 const DEBUG = process.env.NODE_DEBUG && /fs/.test(process.env.NODE_DEBUG);
 const errnoException = util._errnoException;
+const printDeprecation = require('internal/util').printDeprecationMessage;
 
 function throwOptionsError(options) {
  throw new TypeError('Expected options to be either an object or a string, ' +
@@ -584,9 +585,14 @@ fs.openSync = function(path, flags, mode) {
  return binding.open(pathModule._makeLong(path), stringToFlags(flags), mode);
 };
 
+var readWarned = false;
 fs.read = function(fd, buffer, offset, length, position, callback) {
  if (!(buffer instanceof Buffer)) {
  // legacy string interface (fd, length, position, encoding, callback)
+ readWarned = printDeprecation('fs.read\'s legacy String interface ' +
+ 'is deprecated. Use the Buffer API as ' +
+ 'mentioned in the documentation instead.',
+ readWarned);
  const cb = arguments[4];
  const encoding = arguments[3];
 
@@ -636,12 +642,17 @@ function tryToStringWithEnd(buf, encoding, end, callback) {
  callback(e, buf, end);
 }
 
+var readSyncWarned = false;
 fs.readSync = function(fd, buffer, offset, length, position) {
  var legacy = false;
  var encoding;
 
  if (!(buffer instanceof Buffer)) {
  // legacy string interface (fd, length, position, encoding, callback)
+ readSyncWarned = printDeprecation('fs.readSync\'s legacy String interface' +
+ 'is deprecated. Use the Buffer API as ' +
+ 'mentioned in the documentation instead.',
+ readSyncWarned);
  legacy = true;
  encoding = arguments[3];