WPinternals/DiscUtils/Ntfs/StructuredNtfsAttribute.cs

//
// Copyright (c) 2008-2011, Kenneth Bell
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//

namespace DiscUtils.Ntfs
{
    using System.IO;

    internal class StructuredNtfsAttribute<T> : NtfsAttribute
        where T : IByteArraySerializable, IDiagnosticTraceable, new()
    {
        private T _structure;
        private bool _initialized;
        private bool _hasContent;

        public StructuredNtfsAttribute(File file, FileRecordReference containingFile, AttributeRecord record)
            : base(file, containingFile, record)
        {
            _structure = new T();
        }

        public T Content
        {
            get
            {
                Initialize();
                return _structure;
            }

            set
            {
                _structure = value;
                _hasContent = true;
            }
        }

        public bool HasContent
        {
            get
            {
                Initialize();
                return _hasContent;
            }
        }

        public void Save()
        {
            byte[] buffer = new byte[_structure.Size];
            _structure.WriteTo(buffer, 0);
            using (Stream s = Open(FileAccess.Write))
            {
                s.Write(buffer, 0, buffer.Length);
                s.SetLength(buffer.Length);
            }
        }

        public override string ToString()
        {
            Initialize();
            return _structure.ToString();
        }

        public override void Dump(TextWriter writer, string indent)
        {
            Initialize();
            writer.WriteLine(indent + AttributeTypeName + " ATTRIBUTE (" + (Name == null ? "No Name" : Name) + ")");
            _structure.Dump(writer, indent + "  ");

            _primaryRecord.Dump(writer, indent + "  ");
        }

        private void Initialize()
        {
            if (!_initialized)
            {
                using (Stream s = Open(FileAccess.Read))
                {
                        byte[] buffer = Utilities.ReadFully(s, (int)Length);
                        _structure.ReadFrom(buffer, 0);
                        _hasContent = s.Length != 0;
                }

                _initialized = true;
            }
        }
    }
}