Keep the SFTP v3 longname of directory entries

src/Renci.SshNet/Sftp/Responses/SftpNameResponse.cs

@@ -34,12 +34,15 @@ protected override void LoadData()
             for (var i = 0; i < Count; i++)
             {
                 var fileName = ReadString(Encoding);
+                string longName = null;
                 if (SupportsLongName(ProtocolVersion))
                 {
-                    _ = ReadString(Encoding); // skip longname
+                    longName = ReadString(Encoding);
                 }
 
-                Files[i] = new KeyValuePair<string, SftpFileAttributes>(fileName, ReadAttributes());
+                var attributes = ReadAttributes();
+                attributes.LongName = longName;
+                Files[i] = new KeyValuePair<string, SftpFileAttributes>(fileName, attributes);
             }
         }
 
@@ -57,7 +60,7 @@ protected override void SaveData()
 
                 if (SupportsLongName(ProtocolVersion))
                 {
-                    Write(0U); // longname
+                    Write(file.Value.LongName ?? string.Empty, Encoding); // longname
                 }
 
                 Write(file.Value.GetBytes()); // attrs

src/Renci.SshNet/Sftp/SftpFile.cs

@@ -19,6 +19,24 @@ public sealed class SftpFile : ISftpFile
         /// </summary>
         public SftpFileAttributes Attributes { get; private set; }
 
+        /// <summary>
+        /// Gets the "longname" that the server sent for this file in a directory listing.
+        /// </summary>
+        /// <value>
+        /// A line in the style of the output of <c>ls -l</c>, such as
+        /// <c>-rw-r--r--    1 owner    group        1024 Oct  9 14:31 file.txt</c>, which servers commonly use to show
+        /// the names of the owner and the group; or <see langword="null"/> if the server did not send one (SFTP
+        /// protocol version 4 and later) or if this instance was not obtained from a directory listing.
+        /// </value>
+        /// <remarks>
+        /// The SFTP protocol does not specify the format of this line: it is meant to be displayed to users. Use
+        /// <see cref="Attributes"/> for the attributes of the file.
+        /// </remarks>
+        public string LongName
+        {
+            get { return Attributes.LongName; }
+        }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="SftpFile"/> class.
         /// </summary>

src/Renci.SshNet/Sftp/SftpFileAttributes.cs

@@ -570,6 +570,16 @@ public bool OthersCanExecute
 
         internal uint Permissions { get; private set; }
 
+        /// <summary>
+        /// Gets or sets the "longname" that the server sent with these attributes in an SSH_FXP_NAME response, or
+        /// <see langword="null"/> if it sent none.
+        /// </summary>
+        /// <remarks>
+        /// It is not part of the attributes on the wire: it is kept here so that it reaches the <see cref="SftpFile"/>
+        /// created from a directory listing.
+        /// </remarks>
+        internal string? LongName { get; set; }
+
         internal SftpFileAttributes(DateTime lastAccessTimeUtc, DateTime lastWriteTimeUtc, long size, int userId, int groupId, uint permissions, Dictionary<string, string>? extensions)
         {
             LastAccessTimeUtc = _originalLastAccessTimeUtc = lastAccessTimeUtc;

test/Renci.SshNet.Tests/Classes/Sftp/Responses/SftpNameResponseTest.cs

@@ -0,0 +1,80 @@
+using System.Collections.Generic;
+using System.Text;
+
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+using Renci.SshNet.Common;
+using Renci.SshNet.Sftp;
+using Renci.SshNet.Sftp.Responses;
+using Renci.SshNet.Tests.Common;
+
+namespace Renci.SshNet.Tests.Classes.Sftp.Responses
+{
+    [TestClass]
+    public class SftpNameResponseTest
+    {
+        private const string LongName = "-rw-r--r--    1 owner    group        1024 Oct  9 14:31 file.txt";
+
+        [TestMethod]
+        public void Load_ProtocolVersion3_KeepsTheLongNameOfEachFile()
+        {
+            var attributesBytes = SftpFileAttributesBuilder.Empty.GetBytes();
+            var sshDataStream = new SshDataStream(0);
+            sshDataStream.Write(1U); // response id
+            sshDataStream.Write(2U); // count
+            sshDataStream.Write("file.txt", Encoding.UTF8);
+            sshDataStream.Write(LongName, Encoding.UTF8);
+            sshDataStream.Write(attributesBytes);
+            sshDataStream.Write("other", Encoding.UTF8);
+            sshDataStream.Write(string.Empty, Encoding.UTF8);
+            sshDataStream.Write(attributesBytes);
+
+            var target = new SftpNameResponse(3, Encoding.UTF8);
+            target.Load(sshDataStream.ToArray());
+
+            Assert.AreEqual(2U, target.Count);
+            Assert.AreEqual("file.txt", target.Files[0].Key);
+            Assert.AreEqual(LongName, target.Files[0].Value.LongName);
+            Assert.AreEqual("other", target.Files[1].Key);
+            Assert.AreEqual(string.Empty, target.Files[1].Value.LongName);
+        }
+
+        [TestMethod]
+        public void Load_ProtocolVersion4_HasNoLongName()
+        {
+            var attributesBytes = SftpFileAttributesBuilder.Empty.GetBytes();
+            var sshDataStream = new SshDataStream(0);
+            sshDataStream.Write(1U); // response id
+            sshDataStream.Write(1U); // count
+            sshDataStream.Write("file.txt", Encoding.UTF8);
+            sshDataStream.Write(attributesBytes);
+
+            var target = new SftpNameResponse(4, Encoding.UTF8);
+            target.Load(sshDataStream.ToArray());
+
+            Assert.AreEqual("file.txt", target.Files[0].Key);
+            Assert.IsNull(target.Files[0].Value.LongName);
+        }
+
+        [TestMethod]
+        public void GetBytes_ProtocolVersion3_WritesTheLongName()
+        {
+            var attributes = SftpFileAttributesBuilder.Empty;
+            attributes.LongName = LongName;
+            var target = new SftpNameResponse(3, Encoding.UTF8)
+            {
+                ResponseId = 7,
+                Files = [new KeyValuePair<string, SftpFileAttributes>("file.txt", attributes)],
+            };
+
+            var bytes = target.GetBytes();
+
+            // 4 bytes for the length of the SFTP data, 1 byte for the SFTP message type
+            var loaded = new SftpNameResponse(3, Encoding.UTF8);
+            loaded.Load(bytes, 5, bytes.Length - 5);
+            Assert.AreEqual(7U, loaded.ResponseId);
+            Assert.AreEqual("file.txt", loaded.Files[0].Key);
+            Assert.AreEqual(LongName, loaded.Files[0].Value.LongName);
+        }
+    }
+}

test/Renci.SshNet.Tests/Classes/Sftp/SftpFileTest.cs

@@ -0,0 +1,33 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+using Moq;
+
+using Renci.SshNet.Sftp;
+using Renci.SshNet.Tests.Common;
+
+namespace Renci.SshNet.Tests.Classes.Sftp
+{
+    [TestClass]
+    public class SftpFileTest
+    {
+        [TestMethod]
+        public void LongName_FileFromADirectoryListing_IsTheLineSentByTheServer()
+        {
+            const string longName = "drwxr-xr-x    3 owner    group        1024 Oct  9 14:31 dir";
+            var attributes = SftpFileAttributesBuilder.Empty;
+            attributes.LongName = longName;
+
+            var target = new SftpFile(new Mock<ISftpSession>(MockBehavior.Strict).Object, "/home/owner/dir", attributes);
+
+            Assert.AreEqual(longName, target.LongName);
+        }
+
+        [TestMethod]
+        public void LongName_WithoutLongNameFromTheServer_IsNull()
+        {
+            var target = new SftpFile(new Mock<ISftpSession>(MockBehavior.Strict).Object, "/home/owner/file.txt", SftpFileAttributesBuilder.Empty);
+
+            Assert.IsNull(target.LongName);
+        }
+    }
+}