Remote: Add support for the sideband

Enable multiplexing if the server supports it. This allows us to give
feedback to the user when the server is doing work and we're waiting
for the pack data to arrive.

References libgit2#221, libgit2#222

Author: carlosmn

LibGit2Sharp/Indexer.cs

@@ -37,6 +37,28 @@ public ObjectDatabase DatabaseFromPackfile()
             return odb;
         }
 
+        public void Add(byte[] data)
+        {
+            unsafe {
+                var stats = stackalloc byte[Marshal.SizeOf(Stats)];
+                var statsptr = new IntPtr(stats);
+                Marshal.StructureToPtr(Stats, statsptr, true);
+                Ensure.Success(NativeMethods.git_indexer_stream_add(handle, data, new UIntPtr((ulong)data.Length), statsptr));
+                Stats = (IndexerStats)Marshal.PtrToStructure(statsptr, typeof(IndexerStats));
+            }
+        }
+
+        public void Finalize()
+        {
+            unsafe {
+                var stats = stackalloc byte[Marshal.SizeOf(Stats)];
+                var statsptr = new IntPtr(stats);
+                Marshal.StructureToPtr(Stats, statsptr, true);
+                Ensure.Success(NativeMethods.git_indexer_stream_finalize(handle, statsptr));
+                Stats = (IndexerStats)Marshal.PtrToStructure(statsptr, typeof(IndexerStats));
+            }
+        }
+
         public void IndexStream(Stream stream)
         {
             byte[] buffer = new byte[4096];

LibGit2Sharp/Pkt.cs

@@ -11,10 +11,15 @@ static public char[] Line(string msg)
             return string.Format("{0:x4}{1}\n", 4 + msg.Length + 1, msg).ToCharArray();
         }
 
-        static public Pkt Parse(BinaryReader reader)
+        static private int parselen(BinaryReader reader)
         {
             var buf = reader.ReadBytes(4);
-            int len = Int32.Parse(Encoding.ASCII.GetString(buf), System.Globalization.NumberStyles.HexNumber);
+            return Int32.Parse(Encoding.ASCII.GetString(buf), System.Globalization.NumberStyles.HexNumber);
+        }
+
+        static public Pkt Parse(BinaryReader reader)
+        {
+            var len = parselen(reader);
             if (len == 0)
                 return new PktFlush();
 
@@ -23,6 +28,13 @@ static public Pkt Parse(BinaryReader reader)
             return NewPkt(reader, len);
         }
 
+        static public PktDemux Demux(BinaryReader reader)
+        {
+            var len = parselen(reader);
+            len -= 4;
+            return new PktDemux(reader, len);
+        }
+
         /*
          * We can't seek on a NetworkStream, which means that we can't use
          * reader.PeekChar() to see if we got an error (which starts with
@@ -45,6 +57,25 @@ public static Pkt NewPkt(BinaryReader reader, int len)
         }
     }
 
+    public enum Channel
+    {
+        PackData = 1,
+        Progress = 2,
+        Error = 3,
+    }
+
+    public class PktDemux : Pkt
+    {
+        public readonly Channel Channel;
+        public readonly byte[] Data;
+
+        public PktDemux(BinaryReader reader, int len)
+        {
+            Channel = (Channel)reader.ReadByte();
+            len--;
+            Data = reader.ReadBytes(len);
+        }
+    }
 
     public class PktRef : Pkt
     {

LibGit2Sharp/PktParser.cs

@@ -22,5 +22,25 @@ public Pkt Next()
             return Pkt.Parse(reader);
         }
     }
+
+    public class PktDemultiplexer
+    {
+        private BinaryReader reader;
+
+        public PktDemultiplexer(Stream stream)
+            : this(new BinaryReader(stream))
+        {
+        }
+
+        public PktDemultiplexer(BinaryReader reader)
+        {
+            this.reader = reader;
+        }
+
+        public PktDemux Next()
+        {
+            return Pkt.Demux(reader);
+        }
+    }
 }
 

LibGit2Sharp/ProtocolCapabilities.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using System.Collections.Generic;
 
 namespace LibGit2Sharp
 {
@@ -25,8 +26,16 @@ public ProtocolCapabilities(string str)
         public string Common
         {
             get {
-                /* Only this one for now */
-                return OfsDelta ? OfsDeltaStr : "";
+                var list = new List<string>();
+                if (OfsDelta)
+                    list.Add(OfsDeltaStr);
+
+                if (Sideband64k)
+                    list.Add(Sideband64kStr);
+                else if (Sideband)
+                    list.Add(SidebandStr);
+
+                return string.Join(" ", list.ToArray());
             }
         }
     }

LibGit2Sharp/Remote.cs

@@ -8,6 +8,21 @@
 
 namespace LibGit2Sharp
 {
+
+    public class ProgressEventArgs : EventArgs
+    {
+        public Channel Channel;
+        public byte[] Data;
+
+        public ProgressEventArgs(PktDemux pkt)
+        {
+            Channel = pkt.Channel;
+            Data = pkt.Data;
+        }
+    }
+
+    public delegate void ProgressHandler(object sender, ProgressEventArgs args);
+
     /// <summary>
     ///   A remote repository whose branches are tracked.
     /// </summary>
@@ -16,6 +31,7 @@ public class Remote : IEquatable<Remote>
         private readonly ITransport transport;
         public readonly Refspec Refspec;
         public List<PktRef> Refs { get; private set; }
+        public event ProgressHandler Progress;
         private Lazy<IEnumerable<string>> refnames;
         private Lazy<IEnumerable<string>> matching_refs;
         private Indexer indexer;
@@ -128,7 +144,25 @@ public void Download(string path)
             if (!(pkt is PktAck || pkt is PktNak))
                 throw new GitProtocolException("Expected ACK or NAK, got neither");
 
-            indexer.IndexStream(stream);
+            /* If either of these are common, we need to demultiplex it */
+
+            if (!caps.Sideband && !caps.Sideband64k) {
+                indexer.IndexStream(stream);
+            } else {
+                var demux = new PktDemultiplexer(stream);
+                while (true) {
+                    try {
+                        PktDemux p = demux.Next() as PktDemux;
+                        if (p.Channel == Channel.PackData)
+                            indexer.Add(p.Data);
+                        else if (Progress != null)
+                            Progress(this, new ProgressEventArgs(p));
+                    } catch (EndOfStreamException e) {
+                        indexer.Finalize();
+                        break;
+                    }
+                }
+            }
         }
 
         private static readonly LambdaEqualityHelper<Remote> equalityHelper =