Initial change to type-safe Diff.Compare

Fixes #1176.

LibGit2Sharp.Tests/DiffTreeToTreeFixture.cs

@@ -1123,17 +1123,6 @@ public void RetrievingDiffChangesMustAlwaysBeCaseSensitive()
             }
         }
 
-        [Fact]
-        public void CallingCompareWithAnUnsupportedGenericParamThrows()
-        {
-            var path = SandboxStandardTestRepoGitDir();
-            using (var repo = new Repository(path))
-            {
-                Assert.Throws<LibGit2SharpException>(() => repo.Diff.Compare<string>(default(Tree), default(Tree)));
-                Assert.Throws<LibGit2SharpException>(() => repo.Diff.Compare<string>());
-            }
-        }
-
         [Fact]
         public void UsingPatienceAlgorithmCompareOptionProducesPatienceDiff()
         {

LibGit2Sharp/DiffSafeHandleProxy.cs

@@ -0,0 +1,25 @@
+using System;
+using LibGit2Sharp.Core.Handles;
+
+namespace LibGit2Sharp
+{
+    public class DiffSafeHandleProxy : IDisposable
+    {
+        internal readonly DiffSafeHandle nativeHandle;
+
+        internal DiffSafeHandleProxy(DiffSafeHandle handle)
+        {
+            nativeHandle = handle;
+        }
+
+        #region IDisposable implementation
+
+        void IDisposable.Dispose()
+        {
+            nativeHandle.Dispose();
+        }
+
+        #endregion
+    }
+}
+

LibGit2Sharp/IDiffResult.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace LibGit2Sharp
+{
+    public interface IDiffResult<T> where T:class
+    {
+        T FromNative(DiffSafeHandleProxy diff);
+    }
+}
+

LibGit2Sharp/LibGit2Sharp.csproj

@@ -380,6 +380,8 @@
     <Compile Include="Core\GitCertificateSsh.cs" />
     <Compile Include="Core\GitCertificateSshType.cs" />
     <Compile Include="CertificateSsh.cs" />
+    <Compile Include="IDiffResult.cs" />
+    <Compile Include="DiffSafeHandleProxy.cs" />
   </ItemGroup>
   <ItemGroup>
     <CodeAnalysisDictionary Include="CustomDictionary.xml" />

LibGit2Sharp/Patch.cs

@@ -16,7 +16,7 @@ namespace LibGit2Sharp
     /// deleted, modified, ..., then consider using a simpler <see cref="TreeChanges"/>.</para>
     /// </summary>
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
-    public class Patch : IEnumerable<PatchEntryChanges>
+    public class Patch : IEnumerable<PatchEntryChanges>, IDiffResult<Patch>
     {
         private readonly StringBuilder fullPatchBuilder = new StringBuilder();
 
@@ -27,24 +27,9 @@ public class Patch : IEnumerable<PatchEntryChanges>
         /// <summary>
         /// Needed for mocking purposes.
         /// </summary>
-        protected Patch()
+        public Patch()
         { }
 
-        internal Patch(DiffSafeHandle diff)
-        {
-            int count = Proxy.git_diff_num_deltas(diff);
-            for (int i = 0; i < count; i++)
-            {
-                using (var patch = Proxy.git_patch_from_diff(diff, i))
-                {
-                    var delta = Proxy.git_diff_get_delta(diff, i);
-                    AddFileChange(delta);
-                    Proxy.git_patch_print(patch, PrintCallBack);
-                }
-
-            }
-        }
-
         private void AddFileChange(GitDiffDelta delta)
         {
             var treeEntryChanges = new TreeEntryChanges(delta);
@@ -115,6 +100,25 @@ IEnumerator IEnumerable.GetEnumerator()
 
         #endregion
 
+        #region IDiffResult implementation
+
+        Patch IDiffResult<Patch>.FromNative(DiffSafeHandleProxy diff)
+        {
+            int count = Proxy.git_diff_num_deltas(diff.nativeHandle);
+            for (int i = 0; i < count; i++)
+            {
+                using (var patch = Proxy.git_patch_from_diff(diff.nativeHandle, i))
+                {
+                    var delta = Proxy.git_diff_get_delta(diff.nativeHandle, i);
+                    AddFileChange(delta);
+                    Proxy.git_patch_print(patch, PrintCallBack);
+                }
+            }
+            return this;
+        }
+
+        #endregion
+
         /// <summary>
         /// Gets the <see cref="ContentChanges"/> corresponding to the specified <paramref name="path"/>.
         /// </summary>

LibGit2Sharp/PatchStats.cs

@@ -13,40 +13,18 @@ namespace LibGit2Sharp
     /// <para>The individual patches for each file can be accessed through the indexer of this class.</para>
     /// </summary>
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
-    public class PatchStats : IEnumerable<ContentChangeStats>
+    public class PatchStats : IEnumerable<ContentChangeStats>, IDiffResult<PatchStats>
     {
         private readonly IDictionary<FilePath, ContentChangeStats> changes = new Dictionary<FilePath, ContentChangeStats>();
-        private readonly int totalLinesAdded;
-        private readonly int totalLinesDeleted;
+        private int totalLinesAdded;
+        private int totalLinesDeleted;
 
         /// <summary>
         /// For mocking.
         /// </summary>
-        protected PatchStats()
+        public PatchStats()
         { }
 
-        internal PatchStats(DiffSafeHandle diff)
-        {
-            int count = Proxy.git_diff_num_deltas(diff);
-            for (int i = 0; i < count; i++)
-            {
-                using (var patch = Proxy.git_patch_from_diff(diff, i))
-                {
-                    var delta = Proxy.git_diff_get_delta(diff, i);
-                    var pathPtr = delta.NewFile.Path != IntPtr.Zero ? delta.NewFile.Path : delta.OldFile.Path;
-                    var newFilePath = LaxFilePathMarshaler.FromNative(pathPtr);
-
-                    var stats = Proxy.git_patch_line_stats(patch);
-                    int added = stats.Item1;
-                    int deleted = stats.Item2;
-                    changes.Add(newFilePath, new ContentChangeStats(added, deleted));
-                    totalLinesAdded += added;
-                    totalLinesDeleted += deleted;
-                }
-
-            }
-        }
-
         #region IEnumerable<ContentChanges> Members
 
         /// <summary>
@@ -69,6 +47,32 @@ IEnumerator IEnumerable.GetEnumerator()
 
         #endregion
 
+        #region IDiffResult implementation
+
+        PatchStats IDiffResult<PatchStats>.FromNative(DiffSafeHandleProxy diff)
+        {
+            int count = Proxy.git_diff_num_deltas(diff.nativeHandle);
+            for (int i = 0; i < count; i++)
+            {
+                using (var patch = Proxy.git_patch_from_diff(diff.nativeHandle, i))
+                {
+                    var delta = Proxy.git_diff_get_delta(diff.nativeHandle, i);
+                    var pathPtr = delta.NewFile.Path != IntPtr.Zero ? delta.NewFile.Path : delta.OldFile.Path;
+                    var newFilePath = LaxFilePathMarshaler.FromNative(pathPtr);
+
+                    var stats = Proxy.git_patch_line_stats(patch);
+                    int added = stats.Item1;
+                    int deleted = stats.Item2;
+                    changes.Add(newFilePath, new ContentChangeStats(added, deleted));
+                    totalLinesAdded += added;
+                    totalLinesDeleted += deleted;
+                }
+            }
+            return this;
+        }
+
+        #endregion
+
         /// <summary>
         /// Gets the <see cref="ContentChangeStats"/> corresponding to the specified <paramref name="path"/>.
         /// </summary>

LibGit2Sharp/TreeChanges.cs

@@ -15,7 +15,7 @@ namespace LibGit2Sharp
     /// <para>To obtain the actual patch of the diff, use the <see cref="Patch"/> class when calling Compare.</para>.
     /// </summary>
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
-    public class TreeChanges : IEnumerable<TreeEntryChanges>
+    public class TreeChanges : IEnumerable<TreeEntryChanges>, IDiffResult<TreeChanges>
     {
         private readonly List<TreeEntryChanges> changes = new List<TreeEntryChanges>();
         private readonly List<TreeEntryChanges> added = new List<TreeEntryChanges>();
@@ -47,14 +47,9 @@ public class TreeChanges : IEnumerable<TreeEntryChanges>
         /// <summary>
         /// Needed for mocking purposes.
         /// </summary>
-        protected TreeChanges()
+        public TreeChanges()
         { }
 
-        internal TreeChanges(DiffSafeHandle diff)
-        {
-            Proxy.git_diff_foreach(diff, FileCallback, null, null);
-        }
-
         private int FileCallback(GitDiffDelta delta, float progress, IntPtr payload)
         {
             AddFileChange(delta);
@@ -91,6 +86,15 @@ IEnumerator IEnumerable.GetEnumerator()
 
         #endregion
 
+        #region IDiffResult implementation
+
+        TreeChanges IDiffResult<TreeChanges>.FromNative(DiffSafeHandleProxy diff)
+        {
+            Proxy.git_diff_foreach(diff.nativeHandle, FileCallback, null, null);
+            return this;
+        }
+
+        #endregion
 
         /// <summary>
         /// List of <see cref="TreeEntryChanges"/> that have been been added.