Bind git_graph_ahead_behind native method

Replace current implementation of Branch.AheadBy and Branch.BehindBy with git_graph_ahead_behind call

3 files changed, 27 insertions, 2 deletions

diff --git a/LibGit2Sharp/Branch.cs b/LibGit2Sharp/Branch.cs
index 932dcbab..8744b2ff 100644
--- a/LibGit2Sharp/Branch.cs
+++ b/LibGit2Sharp/Branch.cs
@@ -120,7 +120,7 @@ namespace LibGit2Sharp
         /// </summary>
         public virtual int? AheadBy
         {
-            get { return ExistsPathToTrackedBranch() ? repo.Commits.QueryBy(new Filter { Since = Tip, Until = TrackedBranch }).Count() : (int?)null; }
+            get { return ExistsPathToTrackedBranch() ? Proxy.git_graph_ahead_behind(repo.Handle, TrackedBranch.Tip.Id, Tip.Id).Item1 : (int?)null; }
         }
 
         /// <summary>
@@ -132,7 +132,7 @@ namespace LibGit2Sharp
         /// </summary>
         public virtual int? BehindBy
         {
-            get { return ExistsPathToTrackedBranch() ? repo.Commits.QueryBy(new Filter { Since = TrackedBranch, Until = Tip }).Count() : (int?)null; }
+            get { return ExistsPathToTrackedBranch() ? Proxy.git_graph_ahead_behind(repo.Handle, TrackedBranch.Tip.Id, Tip.Id).Item2 : (int?)null; }
         }
 
         /// <summary>
diff --git a/LibGit2Sharp/Core/NativeMethods.cs b/LibGit2Sharp/Core/NativeMethods.cs
index 491cc47f..31b2a763 100644
--- a/LibGit2Sharp/Core/NativeMethods.cs
+++ b/LibGit2Sharp/Core/NativeMethods.cs
@@ -392,6 +392,9 @@ namespace LibGit2Sharp.Core
             IntPtr payload);
 
         [DllImport(libgit2)]
+        internal static extern int git_graph_ahead_behind(out UIntPtr ahead, out UIntPtr behind, RepositorySafeHandle repo, ref GitOid one, ref GitOid two);
+
+        [DllImport(libgit2)]
         internal static extern int git_index_add_from_workdir(
             IndexSafeHandle index,
             [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(FilePathMarshaler))] FilePath path);
diff --git a/LibGit2Sharp/Core/Proxy.cs b/LibGit2Sharp/Core/Proxy.cs
index fd0ee3f4..e704a856 100644
--- a/LibGit2Sharp/Core/Proxy.cs
+++ b/LibGit2Sharp/Core/Proxy.cs
@@ -5,6 +5,7 @@ using System.IO;
 using System.Linq;
 using System.Runtime.InteropServices;
 using System.Threading;
+using LibGit2Sharp.Core.Compat;
 using LibGit2Sharp.Core.Handles;
 using LibGit2Sharp.Handlers;
 
@@ -614,6 +615,27 @@ namespace LibGit2Sharp.Core
 
         #endregion
 
+        #region git_graph_
+
+        public static Tuple<int, int> git_graph_ahead_behind(RepositorySafeHandle repo, ObjectId firstId, ObjectId secondId)
+        {
+            GitOid oid1 = firstId.Oid;
+            GitOid oid2 = secondId.Oid;
+
+            using (ThreadAffinity())
+            {
+                UIntPtr ahead;
+                UIntPtr behind;
+
+                int res = NativeMethods.git_graph_ahead_behind(out ahead, out behind, repo, ref oid1, ref oid2);
+
+                Ensure.Success(res);
+
+                return new Tuple<int, int>((int)ahead, (int)behind);
+            }
+        }
+        #endregion
+
         #region git_index_
 
         public static void git_index_add(IndexSafeHandle index, GitIndexEntry entry)