DiscUtils: Fat: Fix an issue with no long path name support in the upstream library

DiscUtils/DiscUtils.Fat/FatFileStream.cs

@@ -0,0 +1,141 @@
+//
+// 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.Fat
+{
+    using DiscUtils.Streams;
+    using System;
+    using System.Collections.Generic;
+    using System.IO;
+
+    internal class FatFileStream : SparseStream
+    {
+        private Directory _dir;
+        private long _dirId;
+        private ClusterStream _stream;
+
+        private bool didWrite = false;
+
+        public FatFileStream(FatFileSystem fileSystem, Directory dir, long fileId, FileAccess access)
+        {
+            _dir = dir;
+            _dirId = fileId;
+
+            DirectoryEntry dirEntry = _dir.GetEntry(_dirId);
+            _stream = new ClusterStream(fileSystem, access, (uint)dirEntry.FirstCluster, (uint)dirEntry.FileSize);
+            _stream.FirstClusterChanged += FirstClusterAllocatedHandler;
+        }
+
+        public override long Position
+        {
+            get { return _stream.Position; }
+            set { _stream.Position = value; }
+        }
+
+        public override bool CanRead
+        {
+            get { return _stream.CanRead; }
+        }
+
+        public override bool CanSeek
+        {
+            get { return _stream.CanSeek; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return _stream.CanWrite; }
+        }
+
+        public override long Length
+        {
+            get { return _stream.Length; }
+        }
+
+        public override IEnumerable<StreamExtent> Extents
+        {
+            get
+            {
+                return new StreamExtent[] { new StreamExtent(0, Length) };
+            }
+        }
+
+        public override void Close()
+        {
+            if (_dir.FileSystem.CanWrite)
+            {
+                try
+                {
+                    DateTime now = _dir.FileSystem.ConvertFromUtc(DateTime.UtcNow);
+
+                    DirectoryEntry dirEntry = _dir.GetEntry(_dirId);
+                    dirEntry.LastAccessTime = now;
+                    if (didWrite)
+                    {
+                        dirEntry.FileSize = (int)_stream.Length;
+                        dirEntry.LastWriteTime = now;
+                    }
+
+                    _dir.UpdateEntry(_dirId, dirEntry);
+                }
+                finally
+                {
+                    base.Close();
+                }
+            }
+        }
+
+        public override void SetLength(long value)
+        {
+            didWrite = true;
+            _stream.SetLength(value);
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            didWrite = true;
+            _stream.Write(buffer, offset, count);
+        }
+
+        public override void Flush()
+        {
+            _stream.Flush();
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            return _stream.Read(buffer, offset, count);
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            return _stream.Seek(offset, origin);
+        }
+
+        private void FirstClusterAllocatedHandler(uint cluster)
+        {
+            DirectoryEntry dirEntry = _dir.GetEntry(_dirId);
+            dirEntry.FirstCluster = cluster;
+            _dir.UpdateEntry(_dirId, dirEntry);
+        }
+    }
+}