Initial commit - WPinternals 2.6

DiscUtils/Ntfs/NtfsFileStream.cs

@@ -0,0 +1,224 @@
+//
+// 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;
+    using System.Collections.Generic;
+    using System.IO;
+
+    internal sealed class NtfsFileStream : SparseStream
+    {
+        private DirectoryEntry _entry;
+
+        private File _file;
+        private SparseStream _baseStream;
+
+        private bool _isDirty;
+
+        public NtfsFileStream(NtfsFileSystem fileSystem, DirectoryEntry entry, AttributeType attrType, string attrName, FileAccess access)
+        {
+            _entry = entry;
+
+            _file = fileSystem.GetFile(entry.Reference);
+            _baseStream = _file.OpenStream(attrType, attrName, access);
+        }
+
+        public override bool CanRead
+        {
+            get
+            {
+                AssertOpen();
+                return _baseStream.CanRead;
+            }
+        }
+
+        public override bool CanSeek
+        {
+            get
+            {
+                AssertOpen();
+                return _baseStream.CanSeek;
+            }
+        }
+
+        public override bool CanWrite
+        {
+            get
+            {
+                AssertOpen();
+                return _baseStream.CanWrite;
+            }
+        }
+
+        public override long Length
+        {
+            get
+            {
+                AssertOpen();
+                return _baseStream.Length;
+            }
+        }
+
+        public override long Position
+        {
+            get
+            {
+                AssertOpen();
+                return _baseStream.Position;
+            }
+
+            set
+            {
+                AssertOpen();
+                using (new NtfsTransaction())
+                {
+                    _baseStream.Position = value;
+                }
+            }
+        }
+
+        public override IEnumerable<StreamExtent> Extents
+        {
+            get
+            {
+                AssertOpen();
+                return _baseStream.Extents;
+            }
+        }
+
+        public override void Close()
+        {
+            if (_baseStream == null)
+            {
+                return;
+            }
+
+            using (new NtfsTransaction())
+            {
+                base.Close();
+                _baseStream.Close();
+
+                UpdateMetadata();
+
+                _baseStream = null;
+            }
+        }
+
+        public override void Flush()
+        {
+            AssertOpen();
+            using (new NtfsTransaction())
+            {
+                _baseStream.Flush();
+
+                UpdateMetadata();
+            }
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            AssertOpen();
+            Utilities.AssertBufferParameters(buffer, offset, count);
+
+            using (new NtfsTransaction())
+            {
+                return _baseStream.Read(buffer, offset, count);
+            }
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            AssertOpen();
+            using (new NtfsTransaction())
+            {
+                return _baseStream.Seek(offset, origin);
+            }
+        }
+
+        public override void SetLength(long value)
+        {
+            AssertOpen();
+            using (new NtfsTransaction())
+            {
+                if (value != Length)
+                {
+                    _isDirty = true;
+                    _baseStream.SetLength(value);
+                }
+            }
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            AssertOpen();
+            Utilities.AssertBufferParameters(buffer, offset, count);
+
+            using (new NtfsTransaction())
+            {
+                _isDirty = true;
+                _baseStream.Write(buffer, offset, count);
+            }
+        }
+
+        public override void Clear(int count)
+        {
+            AssertOpen();
+            using (new NtfsTransaction())
+            {
+                _isDirty = true;
+                _baseStream.Clear(count);
+            }
+        }
+
+        private void UpdateMetadata()
+        {
+            if (!_file.Context.ReadOnly)
+            {
+                // Update the standard information attribute - so it reflects the actual file state
+                if (_isDirty)
+                {
+                    _file.Modified();
+                }
+                else
+                {
+                    _file.Accessed();
+                }
+
+                // Update the directory entry used to open the file, so it's accurate
+                _entry.UpdateFrom(_file);
+
+                // Write attribute changes back to the Master File Table
+                _file.UpdateRecordInMft();
+                _isDirty = false;
+            }
+        }
+
+        private void AssertOpen()
+        {
+            if (_baseStream == null)
+            {
+                throw new ObjectDisposedException(_entry.Details.FileName, "Attempt to use closed stream");
+            }
+        }
+    }
+}