From 4b46919bf55e60becbca4e23efc2ce6f943b1926 Mon Sep 17 00:00:00 2001
From: nulltoken <emeric.fermas@gmail.com>
Date: Sat, 21 May 2011 13:40:57 +0200
Subject: [PATCH] Improve performance of resolving of direct references

---
 LibGit2Sharp/DirectReference.cs   | 29 ++++++++++++++++++++++++-----
 LibGit2Sharp/Reference.cs         |  8 +++-----
 LibGit2Sharp/SymbolicReference.cs |  5 -----
 3 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/LibGit2Sharp/DirectReference.cs b/LibGit2Sharp/DirectReference.cs
index cc79e5d7c..7a3feb9a7 100644
--- a/LibGit2Sharp/DirectReference.cs
+++ b/LibGit2Sharp/DirectReference.cs
@@ -1,18 +1,37 @@
-namespace LibGit2Sharp
+using System;
+
+namespace LibGit2Sharp
 {
     /// <summary>
     ///   A DirectReference points directly to a <see cref = "GitObject" />
     /// </summary>
     public class DirectReference : Reference
     {
+        private readonly Func<GitObject> targetResolver;
+        private bool resolved;
+        private GitObject target;
+        
+        internal DirectReference(Func<GitObject> targetResolver)
+        {
+            this.targetResolver = targetResolver;
+        }
+
         /// <summary>
         ///   Gets the target of this <see cref = "DirectReference" />
         /// </summary>
-        public GitObject Target { get; internal set; }
-
-        protected override object ProvideAdditionalEqualityComponent()
+        public GitObject Target
         {
-            return Target;
+            get
+            {
+                if (resolved)
+                {
+                    return target;
+                }
+
+                target = targetResolver();
+                resolved = true;
+                return target;
+            }
         }
 
         /// <summary>
diff --git a/LibGit2Sharp/Reference.cs b/LibGit2Sharp/Reference.cs
index fd73026a3..8aad7494d 100644
--- a/LibGit2Sharp/Reference.cs
+++ b/LibGit2Sharp/Reference.cs
@@ -11,7 +11,7 @@ namespace LibGit2Sharp
     public abstract class Reference : IEquatable<Reference>
     {
         private static readonly LambdaEqualityHelper<Reference> equalityHelper =
-            new LambdaEqualityHelper<Reference>(new Func<Reference, object>[] { x => x.CanonicalName, x => x.ProvideAdditionalEqualityComponent() });
+            new LambdaEqualityHelper<Reference>(new Func<Reference, object>[] { x => x.CanonicalName, x => x.TargetIdentifier });
 
         /// <summary>
         ///   Gets the full name of this reference.
@@ -57,8 +57,8 @@ public abstract class Reference : IEquatable<Reference>
                     var targetId = new ObjectId(oid);
                     targetIdentifier = targetId.Sha;
 
-                    var target = repo.Lookup(targetId);
-                    reference = new DirectReference { CanonicalName = name, Target = target, TargetIdentifier = targetIdentifier};
+                    var targetResolver = new Func<GitObject>(() => repo.Lookup(targetId));
+                    reference = new DirectReference(targetResolver) { CanonicalName = name, TargetIdentifier = targetIdentifier};
                     break;
 
                 default:
@@ -88,8 +88,6 @@ public abstract class Reference : IEquatable<Reference>
                               Enum.GetName(typeof (GitReferenceType), type)));
         }
 
-        protected abstract object ProvideAdditionalEqualityComponent();
-
         /// <summary>
         ///   Recursively peels the target of the reference until a direct reference is encountered.
         /// </summary>
diff --git a/LibGit2Sharp/SymbolicReference.cs b/LibGit2Sharp/SymbolicReference.cs
index 0ddc5be67..e1a8290aa 100644
--- a/LibGit2Sharp/SymbolicReference.cs
+++ b/LibGit2Sharp/SymbolicReference.cs
@@ -10,11 +10,6 @@ public class SymbolicReference : Reference
         /// </summary>
         public Reference Target { get; internal set; }
 
-        protected override object ProvideAdditionalEqualityComponent()
-        {
-            return Target;
-        }
-
         /// <summary>
         ///   Recursively peels the target of the reference until a direct reference is encountered.
         /// </summary>