CommitFilter: add simplify-by-first-parent option

Now that this is doable directly inside the revision walker, let's
expose it as a possible filter option.

This fixes #258.

1 files changed, 6 insertions, 0 deletions

diff --git a/LibGit2Sharp/CommitFilter.cs b/LibGit2Sharp/CommitFilter.cs
index 43d26bbb..5635fc52 100644
--- a/LibGit2Sharp/CommitFilter.cs
+++ b/LibGit2Sharp/CommitFilter.cs
@@ -16,6 +16,7 @@ namespace LibGit2Sharp
         {
             SortBy = CommitSortStrategies.Time;
             Since = "HEAD";
+            FirstParent = false;
         }
 
         /// <summary>
@@ -57,6 +58,11 @@ namespace LibGit2Sharp
             get { return ToList(Until); }
         }
 
+        /// <summary>
+        /// Whether to limit the walk to each commit's first parent, instead of all of them
+        /// </summary>
+        public bool FirstParent { get; set; }
+
         private static IList<object> ToList(object obj)
         {
             var list = new List<object>();