feature<TextDiffView>: supports line staging/unstaging in working copy diff view

src/Commands/QueryStagedFileBlobGuid.cs

@@ -0,0 +1,23 @@
+using System.Text.RegularExpressions;
+
+namespace SourceGit.Commands {
+    public class QueryStagedFileBlobGuid : Command {
+        private static readonly Regex REG_FORMAT = new Regex(@"^\d+\s+([0-9a-f]+)\s+.*$");
+
+        public QueryStagedFileBlobGuid(string repo, string file) {
+            WorkingDirectory = repo;
+            Context = repo;
+            Args = $"ls-files -s -- \"{file}\"";
+        }
+
+        public string Result() {
+            var rs = ReadToEnd();
+            var match = REG_FORMAT.Match(rs.StdOut.Trim());
+            if (match.Success) {
+                return match.Groups[1].Value;
+            }
+
+            return string.Empty;
+        }
+    }
+}