fs: Throw early on invalid encoding args

Re #3918

lib/fs.js

@@ -52,6 +52,13 @@ var O_WRONLY = constants.O_WRONLY || 0;
 
 var isWindows = process.platform === 'win32';
 
+function assertEncoding(encoding) {
+  if (encoding && !Buffer.isEncoding(encoding)) {
+    throw new Error('Unknown encoding: ' + encoding);
+  }
+}
+
+
 fs.Stats = binding.Stats;
 
 fs.Stats.prototype._checkModeProperty = function(property) {
@@ -106,6 +113,8 @@ fs.readFile = function(path, encoding_) {
   var callback = arguments[arguments.length - 1];
   if (typeof(callback) !== 'function') callback = function() {};
 
+  assertEncoding(encoding);
+
   // first, stat the file, so we know the size.
   var size;
   var buffer; // single buffer with file data
@@ -179,6 +188,8 @@ fs.readFile = function(path, encoding_) {
 };
 
 fs.readFileSync = function(path, encoding) {
+  assertEncoding(encoding);
+
   var fd = fs.openSync(path, constants.O_RDONLY, 438 /*=0666*/);
 
   var size;
@@ -343,6 +354,9 @@ fs.read = function(fd, buffer, offset, length, position, callback) {
     // legacy string interface (fd, length, position, encoding, callback)
     var cb = arguments[4],
         encoding = arguments[3];
+
+    assertEncoding(encoding);
+
     position = arguments[2];
     length = arguments[1];
     buffer = new Buffer(length);
@@ -371,6 +385,9 @@ fs.readSync = function(fd, buffer, offset, length, position) {
     // legacy string interface (fd, length, position, encoding, callback)
     legacy = true;
     var encoding = arguments[3];
+
+    assertEncoding(encoding);
+
     position = arguments[2];
     length = arguments[1];
     buffer = new Buffer(length);
@@ -392,6 +409,7 @@ fs.write = function(fd, buffer, offset, length, position, callback) {
     // legacy string interface (fd, data, position, encoding, callback)
     callback = arguments[4];
     position = arguments[2];
+    assertEncoding(arguments[3]);
 
     buffer = new Buffer('' + arguments[1], arguments[3]);
     offset = 0;
@@ -419,6 +437,7 @@ fs.writeSync = function(fd, buffer, offset, length, position) {
   if (!Buffer.isBuffer(buffer)) {
     // legacy string interface (fd, data, position, encoding)
     position = arguments[2];
+    assertEncoding(arguments[3]);
 
     buffer = new Buffer('' + arguments[1], arguments[3]);
     offset = 0;
@@ -787,6 +806,8 @@ function writeAll(fd, buffer, offset, length, position, callback) {
 
 fs.writeFile = function(path, data, encoding_, callback) {
   var encoding = (typeof(encoding_) == 'string' ? encoding_ : 'utf8');
+  assertEncoding(encoding);
+
   var callback_ = arguments[arguments.length - 1];
   callback = (typeof(callback_) == 'function' ? callback_ : null);
   fs.open(path, 'w', 438 /*=0666*/, function(openErr, fd) {
@@ -801,6 +822,8 @@ fs.writeFile = function(path, data, encoding_, callback) {
 };
 
 fs.writeFileSync = function(path, data, encoding) {
+  assertEncoding(encoding);
+
   var fd = fs.openSync(path, 'w');
   if (!Buffer.isBuffer(data)) {
     data = new Buffer('' + data, encoding || 'utf8');
@@ -818,6 +841,8 @@ fs.writeFileSync = function(path, data, encoding) {
 
 fs.appendFile = function(path, data, encoding_, callback) {
   var encoding = (typeof(encoding_) == 'string' ? encoding_ : 'utf8');
+  assertEncoding(encoding);
+
   var callback_ = arguments[arguments.length - 1];
   callback = (typeof(callback_) == 'function' ? callback_ : null);
 
@@ -829,6 +854,8 @@ fs.appendFile = function(path, data, encoding_, callback) {
 };
 
 fs.appendFileSync = function(path, data, encoding) {
+  assertEncoding(encoding);
+
   var fd = fs.openSync(path, 'a');
   if (!Buffer.isBuffer(data)) {
     data = new Buffer('' + data, encoding || 'utf8');
@@ -1288,6 +1315,8 @@ var ReadStream = fs.ReadStream = function(path, options) {
     this[key] = options[key];
   }
 
+  assertEncoding(this.encoding);
+
   if (this.encoding) this.setEncoding(this.encoding);
 
   if (this.start !== undefined) {
@@ -1331,6 +1360,7 @@ util.inherits(ReadStream, Stream);
 fs.FileReadStream = fs.ReadStream; // support the legacy name
 
 ReadStream.prototype.setEncoding = function(encoding) {
+  assertEncoding(encoding);
   var StringDecoder = require('string_decoder').StringDecoder; // lazy load
   this._decoder = new StringDecoder(encoding);
 };
@@ -1584,6 +1614,7 @@ WriteStream.prototype.write = function(data) {
   if (!Buffer.isBuffer(data)) {
     var encoding = 'utf8';
     if (typeof(arguments[1]) == 'string') encoding = arguments[1];
+    assertEncoding(encoding);
     data = new Buffer('' + data, encoding);
   }
 
@@ -1670,6 +1701,7 @@ SyncWriteStream.prototype.write = function(data, arg1, arg2) {
       throw new Error('bad arg');
     }
   }
+  assertEncoding(encoding);
 
   // Change strings to buffers. SLOW
   if (typeof data == 'string') {