project: reorganize the structure of the project.

* remove dotnet-tool.json because the project does not rely on any dotnet tools.
* remove Directory.Build.props because the solution has only one project.
* move src/SourceGit to src. It's not needed to put all sources into a subfolder of src since there's only one project.

src/Commands/QueryBranches.cs

@@ -0,0 +1,112 @@
+using System;
+using System.Collections.Generic;
+using System.Text.RegularExpressions;
+
+namespace SourceGit.Commands
+{
+    public partial class QueryBranches : Command
+    {
+        private const string PREFIX_LOCAL = "refs/heads/";
+        private const string PREFIX_REMOTE = "refs/remotes/";
+
+        [GeneratedRegex(@"^(\d+)\s(\d+)$")]
+        private static partial Regex REG_AHEAD_BEHIND();
+
+        public QueryBranches(string repo)
+        {
+            WorkingDirectory = repo;
+            Context = repo;
+            Args = "branch -l --all -v --format=\"%(refname)$%(objectname)$%(HEAD)$%(upstream)$%(upstream:trackshort)\"";
+        }
+
+        public List<Models.Branch> Result()
+        {
+            Exec();
+
+            foreach (var b in _branches)
+            {
+                if (b.IsLocal && !string.IsNullOrEmpty(b.UpstreamTrackStatus))
+                {
+                    if (b.UpstreamTrackStatus == "=")
+                    {
+                        b.UpstreamTrackStatus = string.Empty;
+                    }
+                    else
+                    {
+                        b.UpstreamTrackStatus = ParseTrackStatus(b.Name, b.Upstream);
+                    }
+                }
+            }
+
+            return _branches;
+        }
+
+        protected override void OnReadline(string line)
+        {
+            var parts = line.Split('$');
+            if (parts.Length != 5)
+                return;
+
+            var branch = new Models.Branch();
+            var refName = parts[0];
+            if (refName.EndsWith("/HEAD", StringComparison.Ordinal))
+                return;
+
+            if (refName.StartsWith(PREFIX_LOCAL, StringComparison.Ordinal))
+            {
+                branch.Name = refName.Substring(PREFIX_LOCAL.Length);
+                branch.IsLocal = true;
+            }
+            else if (refName.StartsWith(PREFIX_REMOTE, StringComparison.Ordinal))
+            {
+                var name = refName.Substring(PREFIX_REMOTE.Length);
+                var shortNameIdx = name.IndexOf('/', StringComparison.Ordinal);
+                if (shortNameIdx < 0)
+                    return;
+
+                branch.Remote = name.Substring(0, shortNameIdx);
+                branch.Name = name.Substring(branch.Remote.Length + 1);
+                branch.IsLocal = false;
+            }
+            else
+            {
+                branch.Name = refName;
+                branch.IsLocal = true;
+            }
+
+            branch.FullName = refName;
+            branch.Head = parts[1];
+            branch.IsCurrent = parts[2] == "*";
+            branch.Upstream = parts[3];
+            branch.UpstreamTrackStatus = parts[4];
+            _branches.Add(branch);
+        }
+
+        private string ParseTrackStatus(string local, string upstream)
+        {
+            var cmd = new Command();
+            cmd.WorkingDirectory = WorkingDirectory;
+            cmd.Context = Context;
+            cmd.Args = $"rev-list --left-right --count {local}...{upstream}";
+
+            var rs = cmd.ReadToEnd();
+            if (!rs.IsSuccess)
+                return string.Empty;
+
+            var match = REG_AHEAD_BEHIND().Match(rs.StdOut);
+            if (!match.Success)
+                return string.Empty;
+
+            var ahead = int.Parse(match.Groups[1].Value);
+            var behind = int.Parse(match.Groups[2].Value);
+            var track = "";
+            if (ahead > 0)
+                track += $"{ahead}↑";
+            if (behind > 0)
+                track += $" {behind}↓";
+            return track.Trim();
+        }
+
+        private readonly List<Models.Branch> _branches = new List<Models.Branch>();
+    }
+}