[THRIFT-882] deep copy of binary fields does not copy ByteBuffer characteristics (arrayOffset, position)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.4
• Fix Version/s: 0.5
• Component/s: Java - Compiler
• Patch Info: Patch Available
• Assignee: Bryan Duxbury
• Reporter: Mathias Herberts
• Created: 31/Aug/10 13:40
• Updated: 18/Apr/17 16:59
• Resolved: 17/Sep/10 19:27

Description

Generated objects have a constructor which does a deep copy of an existing instance.

For binary fields, the deep copy is done like that:

    if (other.isSetBinary_field()) {
      this.binary_field = ByteBuffer.wrap(new byte[other.binary_field.limit() - other.binary_field.arrayOffset()]);
      System.arraycopy(other.binary_field.array(), other.binary_field.arrayOffset(), binary_field.array(), 0, other.binary_field.limit() - other.binary_field.arrayOffset());
    }

This copies the backing array of the ByteBuffer but does not set the position correctly.

In various protocol implementations, ByteBuffer instances are serialized by considering data between position and limit, this means that an object created from another object might lead to different serialized data (and thus a different deserialized value) in case a ByteBuffer has a non default position (which can happen since ByteBuffers can be set).