SftpFileStream:

Only allow Append mode when combined with write-only access.
Fixes issue #267.

src/Renci.SshNet.Tests/Classes/Sftp/SftpFileStreamTest_Ctor_FileModeAppend_FileAccessRead.cs

@@ -48,7 +48,7 @@ namespace Renci.SshNet.Tests.Classes.Sftp
         {
             Assert.IsNotNull(_actualException);
             Assert.IsNull(_actualException.InnerException);
-            Assert.AreEqual(string.Format("Combining {0}: {1} with {2}: {3} is invalid.", typeof(FileMode).Name, _fileMode, typeof(FileAccess).Name, _fileAccess), _actualException.Message);
+            Assert.AreEqual(string.Format("{0} mode can be requested only when combined with write-only access.", _fileMode), _actualException.Message);
             Assert.IsNull(_actualException.ParamName);
         }
     }

src/Renci.SshNet.Tests/Classes/Sftp/SftpFileStreamTest_Ctor_FileModeAppend_FileAccessReadWrite.cs

@@ -1,10 +1,7 @@
 using System;
 using System.IO;
-using System.Threading;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
-using Moq;
 using Renci.SshNet.Sftp;
-using Renci.SshNet.Tests.Common;
 
 namespace Renci.SshNet.Tests.Classes.Sftp
 {
@@ -16,11 +13,7 @@ namespace Renci.SshNet.Tests.Classes.Sftp
         private FileMode _fileMode;
         private FileAccess _fileAccess;
         private int _bufferSize;
-        private uint _readBufferSize;
-        private uint _writeBufferSize;
-        private byte[] _handle;
-        private SftpFileStream _target;
-        private SftpFileAttributes _fileAttributes;
+        private ArgumentException _actualException;
 
         protected override void SetupData()
         {
@@ -31,138 +24,32 @@ namespace Renci.SshNet.Tests.Classes.Sftp
             _fileMode = FileMode.Append;
             _fileAccess = FileAccess.ReadWrite;
             _bufferSize = _random.Next(5, 1000);
-            _readBufferSize = (uint) _random.Next(5, 1000);
-            _writeBufferSize = (uint) _random.Next(5, 1000);
-            _handle = GenerateRandom(_random.Next(1, 10), _random);
-            _fileAttributes = new SftpFileAttributesBuilder().WithLastAccessTime(DateTime.Now.AddSeconds(_random.Next()))
-                                                             .WithLastWriteTime(DateTime.Now.AddSeconds(_random.Next()))
-                                                             .WithSize(_random.Next())
-                                                             .WithUserId(_random.Next())
-                                                             .WithGroupId(_random.Next())
-                                                             .WithPermissions((uint)_random.Next())
-                                                             .Build();
         }
 
         protected override void SetupMocks()
         {
-            SftpSessionMock.InSequence(MockSequence)
-                           .Setup(p => p.RequestOpen(_path, Flags.Read | Flags.Write | Flags.Append, false))
-                           .Returns(_handle);
-            SftpSessionMock.InSequence(MockSequence)
-                           .Setup(p => p.CalculateOptimalReadLength((uint)_bufferSize))
-                           .Returns(_readBufferSize);
-            SftpSessionMock.InSequence(MockSequence)
-                           .Setup(p => p.CalculateOptimalWriteLength((uint)_bufferSize, _handle))
-                           .Returns(_writeBufferSize);
-            SftpSessionMock.InSequence(MockSequence)
-                           .Setup(p => p.RequestFStat(_handle, false))
-                           .Returns(_fileAttributes);
         }
 
         protected override void Act()
         {
-            _target = new SftpFileStream(SftpSessionMock.Object,
-                                         _path,
-                                         _fileMode,
-                                         _fileAccess,
-                                         _bufferSize);
+            try
+            {
+                new SftpFileStream(SftpSessionMock.Object, _path, _fileMode, _fileAccess, _bufferSize);
+                Assert.Fail();
+            }
+            catch (ArgumentException ex)
+            {
+                _actualException = ex;
+            }
         }
 
         [TestMethod]
-        public void CanReadShouldReturnTrue()
+        public void CtorShouldHaveThrownArgumentException()
         {
-            Assert.IsTrue(_target.CanRead);
-        }
-
-        [TestMethod]
-        public void CanSeekShouldReturnTrue()
-        {
-            Assert.IsTrue(_target.CanSeek);
-        }
-
-        [TestMethod]
-        public void CanWriteShouldReturnTrue()
-        {
-            Assert.IsTrue(_target.CanWrite);
-        }
-
-        [TestMethod]
-        public void CanTimeoutShouldReturnTrue()
-        {
-            Assert.IsTrue(_target.CanTimeout);
-        }
-
-        [TestMethod]
-        public void PositionShouldReturnSizeOfFile()
-        {
-            SftpSessionMock.InSequence(MockSequence).Setup(p => p.IsOpen).Returns(true);
-
-            var actual = _target.Position;
-
-            Assert.AreEqual(_fileAttributes.Size, actual);
-
-            SftpSessionMock.Verify(p => p.IsOpen, Times.Exactly(1));
-        }
-
-        [TestMethod]
-        public void ReadShouldStartReadingAtEndOfFile()
-        {
-            var buffer = new byte[8];
-            var data = new byte[] {5, 4, 3, 2, 1};
-            var expected = new byte[] {0, 5, 4, 3, 2, 1, 0, 0};
-
-            SftpSessionMock.InSequence(MockSequence).Setup(p => p.IsOpen).Returns(true);
-            SftpSessionMock.InSequence(MockSequence).Setup(p => p.RequestRead(_handle, (ulong)_fileAttributes.Size, _readBufferSize)).Returns(data);
-
-            var actual = _target.Read(buffer, 1, data.Length);
-
-            Assert.AreEqual(data.Length, actual);
-            Assert.IsTrue(buffer.IsEqualTo(expected));
-
-            SftpSessionMock.Verify(p => p.IsOpen, Times.Exactly(1));
-            SftpSessionMock.Verify(p => p.RequestRead(_handle, (ulong)_fileAttributes.Size, _readBufferSize), Times.Once);
-        }
-
-        [TestMethod]
-        public void ReadByteShouldStartReadingAtEndOfFile()
-        {
-            var data = GenerateRandom(5, _random);
-
-            SftpSessionMock.InSequence(MockSequence).Setup(p => p.IsOpen).Returns(true);
-            SftpSessionMock.InSequence(MockSequence).Setup(p => p.RequestRead(_handle, (ulong) _fileAttributes.Size, _readBufferSize)).Returns(data);
-
-            var actual = _target.ReadByte();
-
-            Assert.AreEqual(data[0], actual);
-
-            SftpSessionMock.Verify(p => p.IsOpen, Times.Exactly(1));
-            SftpSessionMock.Verify(p => p.RequestRead(_handle, (ulong) _fileAttributes.Size, _readBufferSize), Times.Once);
-        }
-
-        [TestMethod]
-        public void WriteShouldStartWritingAtEndOfFile()
-        {
-            var buffer = new byte[_writeBufferSize];
-
-            SftpSessionMock.InSequence(MockSequence).Setup(p => p.IsOpen).Returns(true);
-            SftpSessionMock.InSequence(MockSequence).Setup(p => p.RequestWrite(_handle, (ulong) _fileAttributes.Size, buffer, 0, buffer.Length, It.IsNotNull<AutoResetEvent>(), null));
-
-            _target.Write(buffer, 0, buffer.Length);
-
-            SftpSessionMock.Verify(p => p.IsOpen, Times.Exactly(1));
-            SftpSessionMock.Verify(p => p.RequestWrite(_handle, (ulong) _fileAttributes.Size, buffer, 0, buffer.Length, It.IsNotNull<AutoResetEvent>(), null), Times.Once);
-        }
-
-        [TestMethod]
-        public void RequestOpenOnSftpSessionShouldBeInvokedOnce()
-        {
-            SftpSessionMock.Verify(p => p.RequestOpen(_path, Flags.Read | Flags.Write | Flags.Append, false), Times.Once);
-        }
-
-        [TestMethod]
-        public void RequestFStatOnSftpSessionShouldBeInvokedOnce()
-        {
-            SftpSessionMock.Verify(p => p.RequestFStat(_handle, false), Times.Once);
+            Assert.IsNotNull(_actualException);
+            Assert.IsNull(_actualException.InnerException);
+            Assert.AreEqual(string.Format("{0} mode can be requested only when combined with write-only access.", _fileMode), _actualException.Message);
+            Assert.IsNull(_actualException.ParamName);
         }
     }
 }

src/Renci.SshNet/Sftp/SftpFileStream.cs

@@ -202,6 +202,11 @@ namespace Renci.SshNet.Sftp
                     throw new ArgumentOutOfRangeException("access");
             }
 
+            if ((access & FileAccess.Read) != 0 && mode == FileMode.Append)
+            {
+                throw new ArgumentException(string.Format("{0} mode can be requested only when combined with write-only access.", mode.ToString("G")));
+            }
+
             if ((access & FileAccess.Write) == 0)
             {
                 if (mode == FileMode.Create || mode == FileMode.CreateNew || mode == FileMode.Truncate || mode == FileMode.Append)