Ensure that only byte values are sent by sockets and web sockets

sdk/lib/io/common.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.io;
 
 // Constants used when working with native ports.
 // These must match the constants in runtime/bin/dartutils.h class CObject.
 const int _SUCCESS_RESPONSE = 0;
 const int _ILLEGAL_ARGUMENT_RESPONSE = 1;
@@ skipping 82 matching lines @@
 class _BufferAndStart {
   _BufferAndStart(List this.buffer, int this.start);
   List buffer;
   int start;
 }
 
 // Ensure that the input List can be serialized through a native port.
 // Only builtin Lists can be serialized through. If user-defined Lists
 // get here, the contents is copied to a Uint8List. This has the added
 // benefit that it is faster to access from the C code as well.
-_BufferAndStart _ensureFastAndSerializableBuffer(
+_BufferAndStart _ensureFastAndSerializableData(
     List buffer, int start, int end) {
   if (buffer is Uint8List ||
       buffer is Int8List ||
       buffer is Uint16List ||
       buffer is Int16List ||
       buffer is Uint32List ||
       buffer is Int32List ||
       buffer is Uint64List ||
       buffer is Int64List ||
       buffer is ByteData ||
@@ skipping 10 matching lines @@
     if (value is! int) {
       throw new ArgumentError("List element is not an integer at index $j");
     }
     newBuffer[i] = value;
     j++;
   }
   return new _BufferAndStart(newBuffer, 0);
 }
 
 
+_BufferAndStart _ensureFastAndSerializableByteData(
+    List buffer, int start, int end) {
+  if (buffer is Uint8List) {
+    return new _BufferAndStart(buffer, start);
+  }
+  int length = end - start;
+  var newBuffer = new Uint8List(length);
+  int j = start;
+  for (int i = 0; i < length; i++) {
+    int value = buffer[j];
+    if (value is! int ||
+        value < 0 || 255 < value) {
+      throw new ArgumentError(
+          "List element is not a byte value (value $value at index $j)");
+    }
+    newBuffer[i] = value;
+    j++;
+  }
+  return new _BufferAndStart(newBuffer, 0);
+}
+
+
 // TODO(ager): The only reason for the class here is that
 // we cannot patch a top-level function.
 class _BufferUtils {
   // Check if a List is a builtin VM List type. Returns true
   // if the List is a builtin VM List type and false if it is
   // a user defined List type.
   external static bool _isBuiltinList(List buffer);
 }
 
 class _IOCrypto {
   external static Uint8List getRandomBytes(int count);
 }