Split Patch and TreeChanges generation

Remove Patch from TreeChanges
Make repo.Diff.Compare() generic

LibGit2Sharp.Tests/DiffTreeToTargetFixture.cs

@@ -43,9 +43,12 @@ namespace LibGit2Sharp.Tests
             {
                 SetUpSimpleDiffContext(repo);
 
-                TreeChanges changes = repo.Diff.Compare(repo.Head.Tip.Tree,
+                var changes = repo.Diff.Compare<TreeChanges>(repo.Head.Tip.Tree,
                     DiffTargets.WorkingDirectory);
+                Assert.Equal(1, changes.Modified.Count());
 
+                var patch = repo.Diff.Compare<Patch>(repo.Head.Tip.Tree,
+                    DiffTargets.WorkingDirectory);
                 var expected = new StringBuilder()
                     .Append("diff --git a/file.txt b/file.txt\n")
                     .Append("index ce01362..4f125e3 100644\n")
@@ -56,7 +59,7 @@ namespace LibGit2Sharp.Tests
                     .Append("+world\n")
                     .Append("+!!!\n");
 
-                Assert.Equal(expected.ToString(), changes.Patch);
+                Assert.Equal(expected.ToString(), patch);
             }
         }
 
@@ -67,7 +70,7 @@ namespace LibGit2Sharp.Tests
             {
                 Tree tree = repo.Head.Tip.Tree;
 
-                TreeChanges changes = repo.Diff.Compare(tree, DiffTargets.WorkingDirectory);
+                var changes = repo.Diff.Compare<TreeChanges>(tree, DiffTargets.WorkingDirectory);
                 Assert.NotNull(changes);
 
                 Assert.Equal(6, changes.Count());
@@ -103,9 +106,12 @@ namespace LibGit2Sharp.Tests
             {
                 SetUpSimpleDiffContext(repo);
 
-                TreeChanges changes = repo.Diff.Compare(repo.Head.Tip.Tree,
+                var changes = repo.Diff.Compare<TreeChanges>(repo.Head.Tip.Tree,
                     DiffTargets.Index | DiffTargets.WorkingDirectory);
+                Assert.Equal(1, changes.Modified.Count());
 
+                var patch = repo.Diff.Compare<Patch>(repo.Head.Tip.Tree,
+                    DiffTargets.Index | DiffTargets.WorkingDirectory);
                 var expected = new StringBuilder()
                     .Append("diff --git a/file.txt b/file.txt\n")
                     .Append("index ce01362..4f125e3 100644\n")
@@ -116,7 +122,7 @@ namespace LibGit2Sharp.Tests
                     .Append("+world\n")
                     .Append("+!!!\n");
 
-                Assert.Equal(expected.ToString(), changes.Patch);
+                Assert.Equal(expected.ToString(), patch);
             }
         }
 
@@ -158,8 +164,13 @@ namespace LibGit2Sharp.Tests
                 FileStatus state = repo.Index.RetrieveStatus("file.txt");
                 Assert.Equal(FileStatus.Removed | FileStatus.Untracked, state);
 
+                var wrkDirToIdxToTree = repo.Diff.Compare<TreeChanges>(repo.Head.Tip.Tree,
+                    DiffTargets.Index | DiffTargets.WorkingDirectory);
 
-                TreeChanges wrkDirToIdxToTree = repo.Diff.Compare(repo.Head.Tip.Tree,
+                Assert.Equal(1, wrkDirToIdxToTree.Deleted.Count());
+                Assert.Equal(0, wrkDirToIdxToTree.Modified.Count());
+
+                var patch = repo.Diff.Compare<Patch>(repo.Head.Tip.Tree,
                     DiffTargets.Index | DiffTargets.WorkingDirectory);
                 var expected = new StringBuilder()
                     .Append("diff --git a/file.txt b/file.txt\n")
@@ -170,9 +181,15 @@ namespace LibGit2Sharp.Tests
                     .Append("@@ -1 +0,0 @@\n")
                     .Append("-hello\n");
 
-                Assert.Equal(expected.ToString(), wrkDirToIdxToTree.Patch);
+                Assert.Equal(expected.ToString(), patch);
 
-                TreeChanges wrkDirToTree = repo.Diff.Compare(repo.Head.Tip.Tree,
+                var wrkDirToTree = repo.Diff.Compare<TreeChanges>(repo.Head.Tip.Tree,
+                    DiffTargets.WorkingDirectory);
+
+                Assert.Equal(0, wrkDirToTree.Deleted.Count());
+                Assert.Equal(1, wrkDirToTree.Modified.Count());
+
+                patch = repo.Diff.Compare<Patch>(repo.Head.Tip.Tree,
                     DiffTargets.WorkingDirectory);
                 expected = new StringBuilder()
                     .Append("diff --git a/file.txt b/file.txt\n")
@@ -184,7 +201,7 @@ namespace LibGit2Sharp.Tests
                     .Append("+world\n")
                     .Append("+!!!\n");
 
-                Assert.Equal(expected.ToString(), wrkDirToTree.Patch);
+                Assert.Equal(expected.ToString(), patch);
             }
         }
 
@@ -207,9 +224,12 @@ namespace LibGit2Sharp.Tests
             {
                 SetUpSimpleDiffContext(repo);
 
-                TreeChanges changes = repo.Diff.Compare(repo.Head.Tip.Tree,
+                var changes = repo.Diff.Compare<TreeChanges>(repo.Head.Tip.Tree,
                     DiffTargets.Index);
+                Assert.Equal(1, changes.Modified.Count());
 
+                var patch = repo.Diff.Compare<Patch>(repo.Head.Tip.Tree,
+                    DiffTargets.Index);
                 var expected = new StringBuilder()
                     .Append("diff --git a/file.txt b/file.txt\n")
                     .Append("index ce01362..94954ab 100644\n")
@@ -219,7 +239,7 @@ namespace LibGit2Sharp.Tests
                     .Append(" hello\n")
                     .Append("+world\n");
 
-                Assert.Equal(expected.ToString(), changes.Patch);
+                Assert.Equal(expected.ToString(), patch);
             }
         }
 
@@ -254,7 +274,7 @@ namespace LibGit2Sharp.Tests
             {
                 Tree tree = repo.Head.Tip.Tree;
 
-                TreeChanges changes = repo.Diff.Compare(tree, DiffTargets.Index);
+                var changes = repo.Diff.Compare<TreeChanges>(tree, DiffTargets.Index);
                 Assert.NotNull(changes);
 
                 Assert.Equal(3, changes.Count());
@@ -281,7 +301,7 @@ namespace LibGit2Sharp.Tests
             {
                 Tree tree = repo.Head.Tip.Tree;
 
-                TreeChanges changes = repo.Diff.Compare(tree, DiffTargets.Index,
+                var changes = repo.Diff.Compare<TreeChanges>(tree, DiffTargets.Index,
                     new[] { "deleted_staged_file.txt", "1/branch_file.txt" });
 
                 Assert.NotNull(changes);
@@ -305,11 +325,11 @@ namespace LibGit2Sharp.Tests
             {
                 Tree tree = repo.Head.Tip.Tree;
 
-                TreeChanges changes = repo.Diff.Compare(tree, DiffTargets.Index,
+                var changes = repo.Diff.Compare<TreeChanges>(tree, DiffTargets.Index,
                     new[] { "deleted_staged_file.txt", "1/branch_file.txt", "I-do/not-exist" }, new ExplicitPathsOptions { ShouldFailOnUnmatchedPath = false });
                 AssertCanCompareASubsetOfTheTreeAgainstTheIndex(changes);
 
-                changes = repo.Diff.Compare(tree, DiffTargets.Index,
+                changes = repo.Diff.Compare<TreeChanges>(tree, DiffTargets.Index,
                     new[] { "deleted_staged_file.txt", "1/branch_file.txt", "I-do/not-exist" });
                 AssertCanCompareASubsetOfTheTreeAgainstTheIndex(changes);
             }
@@ -322,7 +342,7 @@ namespace LibGit2Sharp.Tests
             {
                 Tree tree = repo.Head.Tip.Tree;
 
-                Assert.Throws<UnmatchedPathException>(() => repo.Diff.Compare(tree, DiffTargets.Index,
+                Assert.Throws<UnmatchedPathException>(() => repo.Diff.Compare<TreeChanges>(tree, DiffTargets.Index,
                     new[] { "deleted_staged_file.txt", "1/branch_file.txt", "I-do/not-exist" }, new ExplicitPathsOptions()));
             }
         }
@@ -359,11 +379,10 @@ namespace LibGit2Sharp.Tests
                 File.AppendAllText(fullpath, "\n");
                 repo.Index.Stage("file.txt");
 
-                TreeChanges changes = repo.Diff.Compare(repo.Head.Tip.Tree, DiffTargets.Index);
+                var changes = repo.Diff.Compare<TreeChanges>(repo.Head.Tip.Tree, DiffTargets.Index);
                 Assert.Equal(1, changes.Modified.Count());
-                Assert.Equal(1, changes.LinesAdded);
-                Assert.Equal(1, changes.LinesDeleted);
 
+                var patch = repo.Diff.Compare<Patch>(repo.Head.Tip.Tree, DiffTargets.Index);
                 var expected = new StringBuilder()
                     .Append("diff --git a/file.txt b/file.txt\n")
                     .Append("index 2e65efe..7898192 100644\n")
@@ -374,7 +393,9 @@ namespace LibGit2Sharp.Tests
                     .Append("\\ No newline at end of file\n")
                     .Append("+a\n");
 
-                Assert.Equal(expected.ToString(), changes.Patch);
+                Assert.Equal(expected.ToString(), patch);
+                Assert.Equal(1, patch.LinesAdded);
+                Assert.Equal(1, patch.LinesDeleted);
             }
         }
 
@@ -384,11 +405,11 @@ namespace LibGit2Sharp.Tests
             using (var repo = new Repository(BareTestRepoPath))
             {
                 Assert.Throws<BareRepositoryException>(
-                    () => repo.Diff.Compare(repo.Head.Tip.Tree, DiffTargets.WorkingDirectory));
+                    () => repo.Diff.Compare<TreeChanges>(repo.Head.Tip.Tree, DiffTargets.WorkingDirectory));
                 Assert.Throws<BareRepositoryException>(
-                    () => repo.Diff.Compare(repo.Head.Tip.Tree, DiffTargets.Index));
+                    () => repo.Diff.Compare<TreeChanges>(repo.Head.Tip.Tree, DiffTargets.Index));
                 Assert.Throws<BareRepositoryException>(
-                    () => repo.Diff.Compare(repo.Head.Tip.Tree, DiffTargets.WorkingDirectory | DiffTargets.Index));
+                    () => repo.Diff.Compare<TreeChanges>(repo.Head.Tip.Tree, DiffTargets.WorkingDirectory | DiffTargets.Index));
             }
         }
 
@@ -401,14 +422,13 @@ namespace LibGit2Sharp.Tests
             {
                 SetUpSimpleDiffContext(repo);
 
-                TreeChanges changes = repo.Diff.Compare(null,
+                var changes = repo.Diff.Compare<TreeChanges>(null,
                     DiffTargets.Index);
 
                 Assert.Equal(1, changes.Count());
                 Assert.Equal(1, changes.Added.Count());
 
                 Assert.Equal("file.txt", changes.Added.Single().Path);
-                Assert.Equal(2, changes.Added.Single().LinesAdded);
             }
         }
 
@@ -421,14 +441,13 @@ namespace LibGit2Sharp.Tests
             {
                 SetUpSimpleDiffContext(repo);
 
-                TreeChanges changes = repo.Diff.Compare(null,
+                var changes = repo.Diff.Compare<TreeChanges>(null,
                     DiffTargets.WorkingDirectory);
 
                 Assert.Equal(1, changes.Count());
                 Assert.Equal(1, changes.Added.Count());
 
                 Assert.Equal("file.txt", changes.Added.Single().Path);
-                Assert.Equal(3, changes.Added.Single().LinesAdded);
             }
         }
 
@@ -441,14 +460,13 @@ namespace LibGit2Sharp.Tests
             {
                 SetUpSimpleDiffContext(repo);
 
-                TreeChanges changes = repo.Diff.Compare(null,
+                var changes = repo.Diff.Compare<TreeChanges>(null,
                     DiffTargets.WorkingDirectory | DiffTargets.Index);
 
                 Assert.Equal(1, changes.Count());
                 Assert.Equal(1, changes.Added.Count());
 
                 Assert.Equal("file.txt", changes.Added.Single().Path);
-                Assert.Equal(3, changes.Added.Single().LinesAdded);
             }
         }
     }

LibGit2Sharp.Tests/DiffTreeToTreeFixture.cs

@@ -19,10 +19,12 @@ namespace LibGit2Sharp.Tests
             {
                 Tree tree = repo.Head.Tip.Tree;
 
-                TreeChanges changes = repo.Diff.Compare(tree, tree);
+                var changes = repo.Diff.Compare<TreeChanges>(tree, tree);
+                var patch = repo.Diff.Compare<Patch>(tree, tree);
 
                 Assert.Empty(changes);
-                Assert.Equal(string.Empty, changes.Patch);
+                Assert.Empty(patch);
+                Assert.Equal(String.Empty, patch);
             }
         }
 
@@ -33,7 +35,7 @@ namespace LibGit2Sharp.Tests
             {
                 Tree tree = repo.Head.Tip.Tree;
 
-                TreeChanges changes = repo.Diff.Compare(tree, tree);
+                var changes = repo.Diff.Compare<TreeChanges>(tree, tree);
 
                 Assert.Null(changes["batman"]);
             }
@@ -52,19 +54,20 @@ namespace LibGit2Sharp.Tests
                 Tree commitTree = repo.Head.Tip.Tree;
                 Tree parentCommitTree = repo.Head.Tip.Parents.Single().Tree;
 
-                TreeChanges changes = repo.Diff.Compare(parentCommitTree, commitTree);
+                var changes = repo.Diff.Compare<TreeChanges>(parentCommitTree, commitTree);
 
                 Assert.Equal(1, changes.Count());
                 Assert.Equal(1, changes.Added.Count());
 
                 TreeEntryChanges treeEntryChanges = changes["1.txt"];
-                Assert.False(treeEntryChanges.IsBinaryComparison);
+
+                var patch = repo.Diff.Compare<Patch>(parentCommitTree, commitTree);
+                Assert.False(patch["1.txt"].IsBinaryComparison);
 
                 Assert.Equal("1.txt", treeEntryChanges.Path);
                 Assert.Equal(ChangeKind.Added, treeEntryChanges.Status);
 
                 Assert.Equal(treeEntryChanges, changes.Added.Single());
-                Assert.Equal(1, treeEntryChanges.LinesAdded);
 
                 Assert.Equal(Mode.Nonexistent, treeEntryChanges.OldMode);
             }
@@ -88,7 +91,7 @@ namespace LibGit2Sharp.Tests
                 Tree tree = repo.Head.Tip.Tree;
                 Tree ancestor = repo.Lookup<Commit>("9fd738e").Tree;
 
-                TreeChanges changes = repo.Diff.Compare(ancestor, tree, new[]{ "1" });
+                var changes = repo.Diff.Compare<TreeChanges>(ancestor, tree, new[] { "1" });
                 Assert.NotNull(changes);
 
                 Assert.Equal(1, changes.Count());
@@ -118,7 +121,7 @@ namespace LibGit2Sharp.Tests
                 Tree commitTree = repo.Head.Tip.Tree;
                 Tree commitTreeWithDifferentAncestor = repo.Branches["refs/remotes/origin/test"].Tip.Tree;
 
-                TreeChanges changes = repo.Diff.Compare(commitTreeWithDifferentAncestor, commitTree);
+                var changes = repo.Diff.Compare<TreeChanges>(commitTreeWithDifferentAncestor, commitTree);
 
                 Assert.Equal(10, changes.Count());
                 Assert.Equal(9, changes.Added.Count());
@@ -128,9 +131,10 @@ namespace LibGit2Sharp.Tests
                 Assert.Equal(new[] { "1.txt", subBranchFilePath, "README", "branch_file.txt", "deleted_staged_file.txt", "deleted_unstaged_file.txt", "modified_staged_file.txt", "modified_unstaged_file.txt", "new.txt" },
                              changes.Added.Select(x => x.Path).OrderBy(p => p, StringComparer.Ordinal).ToArray());
 
-                Assert.Equal(9, changes.LinesAdded);
-                Assert.Equal(2, changes.LinesDeleted);
-                Assert.Equal(2, changes["readme.txt"].LinesDeleted);
+                var patch = repo.Diff.Compare<Patch>(commitTreeWithDifferentAncestor, commitTree);
+                Assert.Equal(9, patch.LinesAdded);
+                Assert.Equal(2, patch.LinesDeleted);
+                Assert.Equal(2, patch["readme.txt"].LinesDeleted);
             }
         }
 
@@ -142,11 +146,11 @@ namespace LibGit2Sharp.Tests
                 Tree commitTree = repo.Head.Tip.Tree;
                 Tree commitTreeWithDifferentAncestor = repo.Branches["refs/remotes/origin/test"].Tip.Tree;
 
-                TreeChanges changes = repo.Diff.Compare(commitTreeWithDifferentAncestor, commitTree,
+                var changes = repo.Diff.Compare<TreeChanges>(commitTreeWithDifferentAncestor, commitTree,
                         new[] { "if-I-exist-this-test-is-really-unlucky.txt" }, new ExplicitPathsOptions { ShouldFailOnUnmatchedPath = false });
                 Assert.Equal(0, changes.Count());
 
-                changes = repo.Diff.Compare(commitTreeWithDifferentAncestor, commitTree,
+                changes = repo.Diff.Compare<TreeChanges>(commitTreeWithDifferentAncestor, commitTree,
                     new[] { "if-I-exist-this-test-is-really-unlucky.txt" });
                 Assert.Equal(0, changes.Count());
             }
@@ -161,7 +165,7 @@ namespace LibGit2Sharp.Tests
                 Tree commitTreeWithDifferentAncestor = repo.Branches["refs/remotes/origin/test"].Tip.Tree;
 
                 Assert.Throws<UnmatchedPathException>(() =>
-                    repo.Diff.Compare(commitTreeWithDifferentAncestor, commitTree,
+                    repo.Diff.Compare<TreeChanges>(commitTreeWithDifferentAncestor, commitTree,
                         new[] { "if-I-exist-this-test-is-really-unlucky.txt" }, new ExplicitPathsOptions()));
             }
         }
@@ -192,7 +196,7 @@ namespace LibGit2Sharp.Tests
                 Tree rootCommitTree = repo.Lookup<Commit>("f8d44d7").Tree;
                 Tree commitTreeWithRenamedFile = repo.Lookup<Commit>("4be51d6").Tree;
 
-                TreeChanges changes = repo.Diff.Compare(rootCommitTree, commitTreeWithRenamedFile);
+                var changes = repo.Diff.Compare<TreeChanges>(rootCommitTree, commitTreeWithRenamedFile);
 
                 Assert.Equal(1, changes.Count());
                 Assert.Equal("super-file.txt", changes["super-file.txt"].Path);
@@ -236,18 +240,21 @@ namespace LibGit2Sharp.Tests
                 Tree rootCommitTree = repo.Lookup<Commit>("f8d44d7").Tree;
                 Tree commitTreeWithUpdatedFile = repo.Lookup<Commit>("ec9e401").Tree;
 
-                TreeChanges changes = repo.Diff.Compare(rootCommitTree, commitTreeWithUpdatedFile,
-                                                        compareOptions: new CompareOptions { ContextLines = contextLines });
+                var changes = repo.Diff.Compare<TreeChanges>(rootCommitTree, commitTreeWithUpdatedFile);
 
                 Assert.Equal(1, changes.Count());
                 Assert.Equal(1, changes.Modified.Count());
-                Assert.Equal(expectedPatchLength, changes.Patch.Length);
 
-                TreeEntryChanges treeEntryChanges = changes.Modified.Single();
+                var patch = repo.Diff.Compare<Patch>(rootCommitTree, commitTreeWithUpdatedFile,
+                                        compareOptions: new CompareOptions { ContextLines = contextLines });
 
-                Assert.Equal(2, treeEntryChanges.LinesAdded);
-                Assert.Equal(1, treeEntryChanges.LinesDeleted);
-                Assert.Equal(expectedPatchLength, treeEntryChanges.Patch.Length);
+                Assert.Equal(expectedPatchLength, patch.Content.Length);
+
+                ContentChanges contentChanges = patch["numbers.txt"];
+
+                Assert.Equal(2, contentChanges.LinesAdded);
+                Assert.Equal(1, contentChanges.LinesDeleted);
+                Assert.Equal(expectedPatchLength, contentChanges.Patch.Length);
             }
         }
 
@@ -326,23 +333,25 @@ namespace LibGit2Sharp.Tests
                 Tree rootCommitTree = repo.Lookup<Commit>("f8d44d7").Tree;
                 Tree mergedCommitTree = repo.Lookup<Commit>("7252fe2").Tree;
 
-                TreeChanges changes = repo.Diff.Compare(rootCommitTree, mergedCommitTree, compareOptions: compareOptions);
+                var changes = repo.Diff.Compare<TreeChanges>(rootCommitTree, mergedCommitTree);
 
                 Assert.Equal(3, changes.Count());
                 Assert.Equal(1, changes.Modified.Count());
                 Assert.Equal(1, changes.Deleted.Count());
                 Assert.Equal(1, changes.Added.Count());
 
-                TreeEntryChanges treeEntryChanges = changes["numbers.txt"];
-
-                Assert.Equal(3, treeEntryChanges.LinesAdded);
-                Assert.Equal(1, treeEntryChanges.LinesDeleted);
-
                 Assert.Equal(Mode.Nonexistent, changes["my-name-does-not-feel-right.txt"].Mode);
+
+                var patch = repo.Diff.Compare<Patch>(rootCommitTree, mergedCommitTree, compareOptions: compareOptions);
+
+                ContentChanges contentChanges = patch["numbers.txt"];
+
+                Assert.Equal(3, contentChanges.LinesAdded);
+                Assert.Equal(1, contentChanges.LinesDeleted);
                 Assert.Equal(Expected("f8d44d7...7252fe2/numbers.txt-{0}-{1}.diff", contextLines, interhunkLines),
-                             treeEntryChanges.Patch);
+                    contentChanges.Patch);
                 Assert.Equal(Expected("f8d44d7...7252fe2/full-{0}-{1}.diff", contextLines, interhunkLines),
-                             changes.Patch);
+                    patch);
             }
         }
 
@@ -369,7 +378,7 @@ namespace LibGit2Sharp.Tests
 
                 Tree treeNew = repo.ObjectDatabase.CreateTree(tdNew);
 
-                TreeChanges changes = repo.Diff.Compare(treeOld, treeNew);
+                var changes = repo.Diff.Compare<TreeChanges>(treeOld, treeNew);
 
                 /*
                  * $ git diff-tree -p 5c87b67 d5278d0
@@ -416,14 +425,14 @@ namespace LibGit2Sharp.Tests
             {
                 Tree tree = repo.Branches["refs/remotes/origin/test"].Tip.Tree;
 
-                TreeChanges changes = repo.Diff.Compare(tree, null);
+                var changes = repo.Diff.Compare<TreeChanges>(tree, null);
 
                 Assert.Equal(1, changes.Count());
                 Assert.Equal(1, changes.Deleted.Count());
 
                 Assert.Equal("readme.txt", changes.Deleted.Single().Path);
 
-                changes = repo.Diff.Compare(null, tree);
+                changes = repo.Diff.Compare<TreeChanges>(null, tree);
 
                 Assert.Equal(1, changes.Count());
                 Assert.Equal(1, changes.Added.Count());
@@ -437,7 +446,7 @@ namespace LibGit2Sharp.Tests
         {
             using (var repo = new Repository(StandardTestRepoPath))
             {
-                TreeChanges changes = repo.Diff.Compare(default(Tree), default(Tree));
+                var changes = repo.Diff.Compare<TreeChanges>(default(Tree), default(Tree));
 
                 Assert.Equal(0, changes.Count());
             }
@@ -460,7 +469,7 @@ namespace LibGit2Sharp.Tests
                 File.WriteAllBytes(fullpath, ((Blob)(entry.Target)).Content);
 
                 // Unset the local core.filemode, if any.
-                repo.Config.Unset("core.filemode", ConfigurationLevel.Local);
+                repo.Config.Unset("core.filemode");
             }
 
             SelfCleaningDirectory scd = BuildSelfCleaningDirectory();
@@ -469,7 +478,7 @@ namespace LibGit2Sharp.Tests
 
             using (var repo = new Repository(path, options))
             {
-                TreeChanges changes = repo.Diff.Compare(new []{ file });
+                var changes = repo.Diff.Compare<TreeChanges>(new[] { file });
 
                 Assert.Equal(1, changes.Count());
 
@@ -482,7 +491,7 @@ namespace LibGit2Sharp.Tests
 
             using (var repo = new Repository(path, options))
             {
-                TreeChanges changes = repo.Diff.Compare(new[] { file });
+                var changes = repo.Diff.Compare<TreeChanges>(new[] { file });
 
                 Assert.Equal(0, changes.Count());
             }
@@ -535,11 +544,21 @@ namespace LibGit2Sharp.Tests
 
             using (var repo = new Repository(repoPath))
             {
-                var changes = repo.Diff.Compare(repo.Lookup<Tree>(treeOldOid), repo.Lookup<Tree>(treeNewOid));
+                var changes = repo.Diff.Compare<TreeChanges>(repo.Lookup<Tree>(treeOldOid), repo.Lookup<Tree>(treeNewOid));
 
                 Assert.Equal(ChangeKind.Modified, changes["a.txt"].Status);
                 Assert.Equal(ChangeKind.Modified, changes["A.TXT"].Status);
             }
         }
+
+        [Fact]
+        public void CallingCompareWithAnUnsupportedGenericParamThrows()
+        {
+            using (var repo = new Repository(StandardTestRepoPath))
+            {
+                Assert.Throws<LibGit2SharpException>(() => repo.Diff.Compare<string>(default(Tree), default(Tree)));
+                Assert.Throws<LibGit2SharpException>(() => repo.Diff.Compare<string>());
+            }
+        }
     }
 }

LibGit2Sharp.Tests/DiffWorkdirToIndexFixture.cs

@@ -32,7 +32,7 @@ namespace LibGit2Sharp.Tests
         {
             using (var repo = new Repository(StandardTestRepoPath))
             {
-                TreeChanges changes = repo.Diff.Compare();
+                var changes = repo.Diff.Compare<TreeChanges>();
 
                 Assert.Equal(2, changes.Count());
                 Assert.Equal("deleted_unstaged_file.txt", changes.Deleted.Single().Path);
@@ -49,10 +49,10 @@ namespace LibGit2Sharp.Tests
             {
                 Assert.Equal(currentStatus, repo.Index.RetrieveStatus(relativePath));
 
-                TreeChanges changes = repo.Diff.Compare(new[] { relativePath }, false, new ExplicitPathsOptions { ShouldFailOnUnmatchedPath = false });
+                var changes = repo.Diff.Compare<TreeChanges>(new[] { relativePath }, false, new ExplicitPathsOptions { ShouldFailOnUnmatchedPath = false });
                 Assert.Equal(0, changes.Count());
 
-                changes = repo.Diff.Compare(new[] { relativePath });
+                changes = repo.Diff.Compare<TreeChanges>(new[] { relativePath });
                 Assert.Equal(0, changes.Count());
             }
         }
@@ -66,7 +66,7 @@ namespace LibGit2Sharp.Tests
             {
                 Assert.Equal(currentStatus, repo.Index.RetrieveStatus(relativePath));
 
-                Assert.Throws<UnmatchedPathException>(() => repo.Diff.Compare(new[] { relativePath }, false, new ExplicitPathsOptions()));
+                Assert.Throws<UnmatchedPathException>(() => repo.Diff.Compare<TreeChanges>(new[] { relativePath }, false, new ExplicitPathsOptions()));
             }
         }
 
@@ -81,7 +81,9 @@ namespace LibGit2Sharp.Tests
             {
                 Assert.Equal(currentStatus, repo.Index.RetrieveStatus(relativePath));
 
-                repo.Diff.Compare(new[] { relativePath }, false, new ExplicitPathsOptions { ShouldFailOnUnmatchedPath = false,
+                repo.Diff.Compare<TreeChanges>(new[] { relativePath }, false, new ExplicitPathsOptions
+                {
+                    ShouldFailOnUnmatchedPath = false,
                     OnUnmatchedPath = callback.OnUnmatchedPath });
 
                 Assert.True(callback.WasCalled);
@@ -124,7 +126,7 @@ namespace LibGit2Sharp.Tests
 
             using (var repo = new Repository(path, options))
             {
-                TreeChanges changes = repo.Diff.Compare(new[] { file });
+                var changes = repo.Diff.Compare<TreeChanges>(new[] { file });
 
                 Assert.Equal(1, changes.Count());
 
@@ -137,7 +139,7 @@ namespace LibGit2Sharp.Tests
 
             using (var repo = new Repository(path, options))
             {
-                TreeChanges changes = repo.Diff.Compare(new[] { file });
+                var changes = repo.Diff.Compare<TreeChanges>(new[] { file });
 
                 Assert.Equal(0, changes.Count());
             }
@@ -168,7 +170,7 @@ namespace LibGit2Sharp.Tests
         {
             using (var repo = new Repository(StandardTestRepoPath))
             {
-                TreeChanges changes = repo.Diff.Compare(null, true);
+                var changes = repo.Diff.Compare<TreeChanges>(null, true);
 
                 Assert.Equal(3, changes.Count());
                 Assert.Equal("deleted_unstaged_file.txt", changes.Deleted.Single().Path);

LibGit2Sharp/Changes.cs

@@ -1,52 +0,0 @@
-using System.Diagnostics;
-using System.Globalization;
-using System.Text;
-
-namespace LibGit2Sharp
-{
-    /// <summary>
-    /// Base class for changes.
-    /// </summary>
-    [DebuggerDisplay("{DebuggerDisplay,nq}")]
-    public abstract class Changes
-    {
-        private readonly StringBuilder patchBuilder = new StringBuilder();
-
-        internal void AppendToPatch(string patch)
-        {
-            patchBuilder.Append(patch);
-        }
-
-        /// <summary>
-        /// The number of lines added.
-        /// </summary>
-        public virtual int LinesAdded { get; internal set; }
-
-        /// <summary>
-        /// The number of lines deleted.
-        /// </summary>
-        public virtual int LinesDeleted { get; internal set; }
-
-        /// <summary>
-        /// The patch corresponding to these changes.
-        /// </summary>
-        public virtual string Patch
-        {
-            get { return patchBuilder.ToString(); }
-        }
-
-        /// <summary>
-        /// Determines if at least one side of the comparison holds binary content.
-        /// </summary>
-        public virtual bool IsBinaryComparison { get; protected set; }
-
-        private string DebuggerDisplay
-        {
-            get
-            {
-                return string.Format(CultureInfo.InvariantCulture,
-                    @"{{+{0}, -{1}}}", LinesAdded, LinesDeleted);
-            }
-        }
-    }
-}

LibGit2Sharp/CompareOptions.cs

@@ -12,7 +12,6 @@ namespace LibGit2Sharp
         {
             ContextLines = 3;
             InterhunkLines = 0;
-            SkipPatchBuilding = false;
         }
 
         /// <summary>
@@ -26,11 +25,5 @@ namespace LibGit2Sharp
         /// (Default = 0)
         /// </summary>
         public int InterhunkLines { get; set; }
-
-        /// <summary>
-        /// Flag to skip patch building. May be used if only file name and status required.
-        /// (Default = false)
-        /// </summary>
-        internal bool SkipPatchBuilding { get; set; }
     }
 }

LibGit2Sharp/ContentChanges.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Diagnostics;
+using System.Globalization;
 using System.Text;
 using LibGit2Sharp.Core;
 
@@ -7,8 +9,12 @@ namespace LibGit2Sharp
     /// <summary>
     /// Holds the changes between two <see cref="Blob"/>s.
     /// </summary>
-    public class ContentChanges : Changes
+    [DebuggerDisplay("{DebuggerDisplay,nq}")]
+    public class ContentChanges
     {
+        private readonly StringBuilder patchBuilder = new StringBuilder();
+        private bool isBinaryComparison;
+
         /// <summary>
         /// Needed for mocking purposes.
         /// </summary>
@@ -23,6 +29,43 @@ namespace LibGit2Sharp
                                  options, FileCallback, HunkCallback, LineCallback);
         }
 
+        internal ContentChanges(bool isBinaryComparison)
+        {
+            this.isBinaryComparison = isBinaryComparison;
+        }
+
+        internal void AppendToPatch(string patch)
+        {
+            patchBuilder.Append(patch);
+        }
+
+        /// <summary>
+        /// The number of lines added.
+        /// </summary>
+        public virtual int LinesAdded { get; internal set; }
+
+        /// <summary>
+        /// The number of lines deleted.
+        /// </summary>
+        public virtual int LinesDeleted { get; internal set; }
+
+        /// <summary>
+        /// The patch corresponding to these changes.
+        /// </summary>
+        public virtual string Patch
+        {
+            get { return patchBuilder.ToString(); }
+        }
+
+        /// <summary>
+        /// Determines if at least one side of the comparison holds binary content.
+        /// </summary>
+        public virtual bool IsBinaryComparison
+        {
+            get { return isBinaryComparison; }
+            private set { isBinaryComparison = value; }
+        }
+
         private int FileCallback(GitDiffDelta delta, float progress, IntPtr payload)
         {
             IsBinaryComparison = delta.IsBinary();
@@ -76,5 +119,14 @@ namespace LibGit2Sharp
             AppendToPatch(decodedContent);
             return 0;
         }
+
+        private string DebuggerDisplay
+        {
+            get
+            {
+                return string.Format(CultureInfo.InvariantCulture,
+                    @"{{+{0}, -{1}}}", LinesAdded, LinesDeleted);
+            }
+        }
     }
 }

LibGit2Sharp/Diff.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using System.Text;
 using LibGit2Sharp.Core;
@@ -77,39 +78,24 @@ namespace LibGit2Sharp
             this.repo = repo;
         }
 
-        /// <summary>
-        /// Show changes between two <see cref="Tree"/>s.
-        /// </summary>
-        /// <param name="oldTree">The <see cref="Tree"/> you want to compare from.</param>
-        /// <param name="newTree">The <see cref="Tree"/> you want to compare to.</param>
-        /// <param name="paths">The list of paths (either files or directories) that should be compared.</param>
-        /// <param name="explicitPathsOptions">
-        /// If set, the passed <paramref name="paths"/> will be treated as explicit paths.
-        /// Use these options to determine how unmatched explicit paths should be handled.
-        /// </param>
-        /// <param name="compareOptions">Additional options to define comparison behavior.</param>
-        /// <returns>A <see cref="TreeChanges"/> containing the changes between the <paramref name="oldTree"/> and the <paramref name="newTree"/>.</returns>
-        public virtual TreeChanges Compare(Tree oldTree, Tree newTree, IEnumerable<string> paths = null, ExplicitPathsOptions explicitPathsOptions = null, CompareOptions compareOptions = null)
+        private static readonly IDictionary<DiffTargets, Func<Repository, TreeComparisonHandleRetriever>> HandleRetrieverDispatcher = BuildHandleRetrieverDispatcher();
+
+        private static IDictionary<DiffTargets, Func<Repository, TreeComparisonHandleRetriever>> BuildHandleRetrieverDispatcher()
         {
-            var comparer = TreeToTree(repo);
-            ObjectId oldTreeId = oldTree != null ? oldTree.Id : null;
-            ObjectId newTreeId = newTree != null ? newTree.Id : null;
-            var diffOptions = DiffModifiers.None;
-
-            if (explicitPathsOptions != null)
-            {
-                diffOptions |= DiffModifiers.DisablePathspecMatch;
-
-                if (explicitPathsOptions.ShouldFailOnUnmatchedPath ||
-                    explicitPathsOptions.OnUnmatchedPath != null)
-                {
-                    diffOptions |= DiffModifiers.IncludeUnmodified;
-                }
-            }
-
-            return BuildTreeChangesFromComparer(oldTreeId, newTreeId, comparer, diffOptions, paths, explicitPathsOptions, compareOptions);
+            return new Dictionary<DiffTargets, Func<Repository, TreeComparisonHandleRetriever>>
+                       {
+                           { DiffTargets.Index, IndexToTree },
+                           { DiffTargets.WorkingDirectory, WorkdirToTree },
+                           { DiffTargets.Index | DiffTargets.WorkingDirectory, WorkdirAndIndexToTree },
+                       };
         }
 
+        private static readonly IDictionary<Type, Func<DiffListSafeHandle, object>> ChangesBuilders = new Dictionary<Type, Func<DiffListSafeHandle, object>>
+        {
+            { typeof(Patch), diff => new Patch(diff) },
+            { typeof(TreeChanges), diff => new TreeChanges(diff) },
+        };
+
         /// <summary>
         /// Show changes between two <see cref="Blob"/>s.
         /// </summary>
@@ -125,37 +111,34 @@ namespace LibGit2Sharp
             }
         }
 
-        private readonly IDictionary<DiffTargets, Func<Repository, TreeComparisonHandleRetriever>> handleRetrieverDispatcher = BuildHandleRetrieverDispatcher();
-
-        private static IDictionary<DiffTargets, Func<Repository, TreeComparisonHandleRetriever>> BuildHandleRetrieverDispatcher()
-        {
-            return new Dictionary<DiffTargets, Func<Repository, TreeComparisonHandleRetriever>>
-                       {
-                           { DiffTargets.Index, IndexToTree },
-                           { DiffTargets.WorkingDirectory, WorkdirToTree },
-                           { DiffTargets.Index | DiffTargets.WorkingDirectory, WorkdirAndIndexToTree },
-                       };
-        }
-
         /// <summary>
-        /// Show changes between a <see cref="Tree"/> and the Index, the Working Directory, or both.
+        /// Show changes between two <see cref="Tree"/>s.
         /// </summary>
-        /// <param name="oldTree">The <see cref="Tree"/> to compare from.</param>
-        /// <param name="diffTargets">The targets to compare to.</param>
+        /// <param name="oldTree">The <see cref="Tree"/> you want to compare from.</param>
+        /// <param name="newTree">The <see cref="Tree"/> you want to compare to.</param>
         /// <param name="paths">The list of paths (either files or directories) that should be compared.</param>
         /// <param name="explicitPathsOptions">
         /// If set, the passed <paramref name="paths"/> will be treated as explicit paths.
         /// Use these options to determine how unmatched explicit paths should be handled.
         /// </param>
-        /// <param name="compareOptions">Additional options to define comparison behavior.</param>
-        /// <returns>A <see cref="TreeChanges"/> containing the changes between the <see cref="Tree"/> and the selected target.</returns>
-        public virtual TreeChanges Compare(Tree oldTree, DiffTargets diffTargets, IEnumerable<string> paths = null, ExplicitPathsOptions explicitPathsOptions = null, CompareOptions compareOptions = null)
+        /// <param name="compareOptions">Additional options to define patch generation behavior.</param>
+        /// <returns>A <see cref="TreeChanges"/> containing the changes between the <paramref name="oldTree"/> and the <paramref name="newTree"/>.</returns>
+        public virtual T Compare<T>(Tree oldTree, Tree newTree, IEnumerable<string> paths = null, ExplicitPathsOptions explicitPathsOptions = null,
+            CompareOptions compareOptions = null) where T : class
         {
-            var comparer = handleRetrieverDispatcher[diffTargets](repo);
-            ObjectId oldTreeId = oldTree != null ? oldTree.Id : null;
+            Func<DiffListSafeHandle, object> builder;
 
-            DiffModifiers diffOptions = diffTargets.HasFlag(DiffTargets.WorkingDirectory) ?
-                DiffModifiers.IncludeUntracked : DiffModifiers.None;
+            if (!ChangesBuilders.TryGetValue(typeof (T), out builder))
+            {
+                throw new LibGit2SharpException(string.Format(CultureInfo.InvariantCulture,
+                    "Unexpected type '{0}' passed to Compare. Supported values are either '{1}' or '{2}'.", typeof (T),
+                    typeof (TreeChanges), typeof (Patch)));
+            }
+
+            var comparer = TreeToTree(repo);
+            ObjectId oldTreeId = oldTree != null ? oldTree.Id : null;
+            ObjectId newTreeId = newTree != null ? newTree.Id : null;
+            var diffOptions = DiffModifiers.None;
 
             if (explicitPathsOptions != null)
             {
@@ -168,11 +151,74 @@ namespace LibGit2Sharp
                 }
             }
 
-            return BuildTreeChangesFromComparer(oldTreeId, null, comparer, diffOptions, paths, explicitPathsOptions, compareOptions);
+            using (DiffListSafeHandle diffList = BuildDiffList(oldTreeId, newTreeId, comparer,
+                diffOptions, paths, explicitPathsOptions, compareOptions))
+            {
+                return (T)builder(diffList);
+            }
+        }
+
+        /// <summary>
+        /// Show changes between a <see cref="Tree"/> and the Index, the Working Directory, or both.
+        /// <para>
+        /// The level of diff performed can be specified by passing either a <see cref="TreeChanges"/>
+        /// or <see cref="Patch"/> type as the generic parameter.
+        /// </para>
+        /// </summary>
+        /// <param name="oldTree">The <see cref="Tree"/> to compare from.</param>
+        /// <param name="diffTargets">The targets to compare to.</param>
+        /// <param name="paths">The list of paths (either files or directories) that should be compared.</param>
+        /// <param name="explicitPathsOptions">
+        /// If set, the passed <paramref name="paths"/> will be treated as explicit paths.
+        /// Use these options to determine how unmatched explicit paths should be handled.
+        /// </param>
+        /// <param name="compareOptions">Additional options to define patch generation behavior.</param>
+        /// <typeparam name="T">Can be either a <see cref="TreeChanges"/> if you are only interested in the list of files modified, added, ..., or
+        /// a <see cref="Patch"/> if you want the actual patch content for the whole diff and for individual files.</typeparam>
+        /// <returns>A <typeparamref name="T"/> containing the changes between the <see cref="Tree"/> and the selected target.</returns>
+        public virtual T Compare<T>(Tree oldTree, DiffTargets diffTargets, IEnumerable<string> paths = null,
+            ExplicitPathsOptions explicitPathsOptions = null, CompareOptions compareOptions = null) where T : class
+        {
+            Func<DiffListSafeHandle, object> builder;
+
+            if (!ChangesBuilders.TryGetValue(typeof (T), out builder))
+            {
+                throw new LibGit2SharpException(string.Format(CultureInfo.InvariantCulture,
+                    "Unexpected type '{0}' passed to Compare. Supported values are either '{1}' or '{2}'.", typeof (T),
+                    typeof (TreeChanges), typeof (Patch)));
+            }
+
+            var comparer = HandleRetrieverDispatcher[diffTargets](repo);
+            ObjectId oldTreeId = oldTree != null ? oldTree.Id : null;
+
+            DiffModifiers diffOptions = diffTargets.HasFlag(DiffTargets.WorkingDirectory)
+                ? DiffModifiers.IncludeUntracked
+                : DiffModifiers.None;
+
+            if (explicitPathsOptions != null)
+            {
+                diffOptions |= DiffModifiers.DisablePathspecMatch;
+
+                if (explicitPathsOptions.ShouldFailOnUnmatchedPath ||
+                    explicitPathsOptions.OnUnmatchedPath != null)
+                {
+                    diffOptions |= DiffModifiers.IncludeUnmodified;
+                }
+            }
+
+            using (DiffListSafeHandle diffList = BuildDiffList(oldTreeId, null, comparer,
+                diffOptions, paths, explicitPathsOptions, compareOptions))
+            {
+                return (T)builder(diffList);
+            }
         }
 
         /// <summary>
         /// Show changes between the working directory and the index.
+        /// <para>
+        /// The level of diff performed can be specified by passing either a <see cref="TreeChanges"/>
+        /// or <see cref="Patch"/> type as the generic parameter.
+        /// </para>
         /// </summary>
         /// <param name="paths">The list of paths (either files or directories) that should be compared.</param>
         /// <param name="includeUntracked">If true, include untracked files from the working dir as additions. Otherwise ignore them.</param>
@@ -180,16 +226,28 @@ namespace LibGit2Sharp
         /// If set, the passed <paramref name="paths"/> will be treated as explicit paths.
         /// Use these options to determine how unmatched explicit paths should be handled.
         /// </param>
-        /// <param name="compareOptions">Additional options to define comparison behavior.</param>
-        /// <returns>A <see cref="TreeChanges"/> containing the changes between the working directory and the index.</returns>
-        public virtual TreeChanges Compare(IEnumerable<string> paths = null, bool includeUntracked = false, ExplicitPathsOptions explicitPathsOptions = null, CompareOptions compareOptions = null)
+        /// <param name="compareOptions">Additional options to define patch generation behavior.</param>
+        /// <typeparam name="T">Can be either a <see cref="TreeChanges"/> if you are only interested in the list of files modified, added, ..., or
+        /// a <see cref="Patch"/> if you want the actual patch content for the whole diff and for individual files.</typeparam>
+        /// <returns>A <typeparamref name="T"/> containing the changes between the working directory and the index.</returns>
+        public virtual T Compare<T>(IEnumerable<string> paths = null, bool includeUntracked = false, ExplicitPathsOptions explicitPathsOptions = null,
+            CompareOptions compareOptions = null) where T : class
         {
-            return Compare(includeUntracked ? DiffModifiers.IncludeUntracked : DiffModifiers.None, paths, explicitPathsOptions, compareOptions);
+            return Compare<T>(includeUntracked ? DiffModifiers.IncludeUntracked : DiffModifiers.None, paths, explicitPathsOptions);
         }
 
-        internal virtual TreeChanges Compare(DiffModifiers diffOptions, IEnumerable<string> paths = null,
-                                             ExplicitPathsOptions explicitPathsOptions = null, CompareOptions compareOptions = null)
+        internal virtual T Compare<T>(DiffModifiers diffOptions, IEnumerable<string> paths = null,
+                                     ExplicitPathsOptions explicitPathsOptions = null, CompareOptions compareOptions = null) where T : class
         {
+            Func<DiffListSafeHandle, object> builder;
+
+            if (!ChangesBuilders.TryGetValue(typeof (T), out builder))
+            {
+                throw new LibGit2SharpException(string.Format(CultureInfo.InvariantCulture,
+                    "Unexpected type '{0}' passed to Compare. Supported values are either '{1}' or '{2}'.", typeof (T),
+                    typeof (TreeChanges), typeof (Patch)));
+            }
+
             var comparer = WorkdirToIndex(repo);
 
             if (explicitPathsOptions != null)
@@ -203,10 +261,14 @@ namespace LibGit2Sharp
                 }
             }
 
-            return BuildTreeChangesFromComparer(null, null, comparer, diffOptions, paths, explicitPathsOptions, compareOptions);
+            using (DiffListSafeHandle diffList = BuildDiffList(null, null, comparer,
+                diffOptions, paths, explicitPathsOptions, compareOptions))
+            {
+                return (T)builder(diffList);
+            }
         }
 
-        private delegate DiffListSafeHandle TreeComparisonHandleRetriever(ObjectId oldTreeId, ObjectId newTreeId, GitDiffOptions options);
+        internal delegate DiffListSafeHandle TreeComparisonHandleRetriever(ObjectId oldTreeId, ObjectId newTreeId, GitDiffOptions options);
 
         private static TreeComparisonHandleRetriever TreeToTree(Repository repo)
         {
@@ -256,23 +318,31 @@ namespace LibGit2Sharp
             return (oh, nh, o) => Proxy.git_diff_tree_to_index(repo.Handle, repo.Index.Handle, oh, o);
         }
 
-        private TreeChanges BuildTreeChangesFromComparer(
-            ObjectId oldTreeId, ObjectId newTreeId, TreeComparisonHandleRetriever comparisonHandleRetriever,
-            DiffModifiers diffOptions, IEnumerable<string> paths = null, ExplicitPathsOptions explicitPathsOptions = null, CompareOptions compareOptions = null)
+        private DiffListSafeHandle BuildDiffList(ObjectId oldTreeId, ObjectId newTreeId, TreeComparisonHandleRetriever comparisonHandleRetriever,
+            DiffModifiers diffOptions, IEnumerable<string> paths, ExplicitPathsOptions explicitPathsOptions,
+            CompareOptions compareOptions)
         {
             var matchedPaths = new MatchedPathsAggregator();
             var filePaths = repo.ToFilePaths(paths);
 
             using (GitDiffOptions options = BuildOptions(diffOptions, filePaths, matchedPaths, compareOptions))
-            using (DiffListSafeHandle diffList = comparisonHandleRetriever(oldTreeId, newTreeId, options))
             {
-                if (explicitPathsOptions != null)
+                var diffList = comparisonHandleRetriever(oldTreeId, newTreeId, options);
+
+                try
                 {
-                    DispatchUnmatchedPaths(explicitPathsOptions, filePaths, matchedPaths);
+                    if (explicitPathsOptions != null)
+                    {
+                        DispatchUnmatchedPaths(explicitPathsOptions, filePaths, matchedPaths);
+                    }
+                }
+                catch
+                {
+                    diffList.Dispose();
+                    throw;
                 }
 
-                bool skipPatchBuilding = (compareOptions != null) && compareOptions.SkipPatchBuilding;
-                return new TreeChanges(diffList, skipPatchBuilding);
+                return diffList;
             }
         }
 

LibGit2Sharp/Index.cs

@@ -156,8 +156,7 @@ namespace LibGit2Sharp
         {
             Ensure.ArgumentNotNull(paths, "paths");
 
-            var compareOptions = new CompareOptions { SkipPatchBuilding = true };
-            TreeChanges changes = repo.Diff.Compare(DiffModifiers.IncludeUntracked | DiffModifiers.IncludeIgnored, paths, explicitPathsOptions, compareOptions);
+            var changes = repo.Diff.Compare<TreeChanges>(DiffModifiers.IncludeUntracked | DiffModifiers.IncludeIgnored, paths, explicitPathsOptions);
 
             foreach (var treeEntryChanges in changes)
             {
@@ -214,8 +213,7 @@ namespace LibGit2Sharp
 
             if (repo.Info.IsHeadUnborn)
             {
-                var compareOptions = new CompareOptions { SkipPatchBuilding = true };
-                TreeChanges changes = repo.Diff.Compare(null, DiffTargets.Index, paths, explicitPathsOptions, compareOptions);
+                var changes = repo.Diff.Compare<TreeChanges>(null, DiffTargets.Index, paths, explicitPathsOptions);
 
                 Reset(changes);
             }
@@ -350,8 +348,7 @@ namespace LibGit2Sharp
         public virtual void Remove(IEnumerable<string> paths, bool removeFromWorkingDirectory = true, ExplicitPathsOptions explicitPathsOptions = null)
         {
             var pathsList = paths.ToList();
-            var compareOptions = new CompareOptions { SkipPatchBuilding = true };
-            TreeChanges changes = repo.Diff.Compare(DiffModifiers.IncludeUnmodified | DiffModifiers.IncludeUntracked, pathsList, explicitPathsOptions, compareOptions);
+            var changes = repo.Diff.Compare<TreeChanges>(DiffModifiers.IncludeUnmodified | DiffModifiers.IncludeUntracked, pathsList, explicitPathsOptions);
 
             var pathsTodelete = pathsList.Where(p => Directory.Exists(Path.Combine(repo.Info.WorkingDirectory, p))).ToList();
 

LibGit2Sharp/LibGit2Sharp.csproj

@@ -64,7 +64,6 @@
     <Compile Include="BranchCollectionExtensions.cs" />
     <Compile Include="BranchTrackingDetails.cs" />
     <Compile Include="BranchUpdater.cs" />
-    <Compile Include="Changes.cs" />
     <Compile Include="CheckoutCallbacks.cs" />
     <Compile Include="CheckoutModifiers.cs" />
     <Compile Include="CheckoutNotificationOptions.cs" />
@@ -83,6 +82,7 @@
     <Compile Include="DiffModifiers.cs" />
     <Compile Include="ObjectType.cs" />
     <Compile Include="Core\UniqueIdentifier.cs" />
+    <Compile Include="Patch.cs" />
     <Compile Include="ReferenceExtensions.cs" />
     <Compile Include="Conflict.cs" />
     <Compile Include="ConflictCollection.cs" />

LibGit2Sharp/Patch.cs

@@ -0,0 +1,176 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Globalization;
+using System.Text;
+using LibGit2Sharp.Core;
+using LibGit2Sharp.Core.Handles;
+
+namespace LibGit2Sharp
+{
+    /// <summary>
+    /// Holds the patch between two trees.
+    /// <para>The individual patches for each file can be accessed through the indexer of this class.</para>
+    /// <para>Building a patch is an expensive operation. If you only need to know which files have been added,
+    /// deleted, modified, ..., then consider using a simpler <see cref="TreeChanges"/>.</para>
+    /// </summary>
+    [DebuggerDisplay("{DebuggerDisplay,nq}")]
+    public class Patch : IEnumerable<ContentChanges>
+    {
+        private readonly StringBuilder fullPatchBuilder = new StringBuilder();
+
+        private readonly IDictionary<FilePath, ContentChanges> changes = new Dictionary<FilePath, ContentChanges>();
+        private int linesAdded;
+        private int linesDeleted;
+
+        /// <summary>
+        /// Needed for mocking purposes.
+        /// </summary>
+        protected Patch()
+        { }
+
+        internal Patch(DiffListSafeHandle diff)
+        {
+            Proxy.git_diff_foreach(diff, FileCallback, null, DataCallback);
+
+            Proxy.git_diff_print_patch(diff, PrintCallBack);
+        }
+
+        private int FileCallback(GitDiffDelta delta, float progress, IntPtr payload)
+        {
+            AddFileChange(delta);
+            return 0;
+        }
+
+        private void AddFileChange(GitDiffDelta delta)
+        {
+            var newFilePath = FilePathMarshaler.FromNative(delta.NewFile.Path);
+
+            changes.Add(newFilePath, new ContentChanges(delta.IsBinary()));
+        }
+
+        private int DataCallback(GitDiffDelta delta, GitDiffRange range, GitDiffLineOrigin lineOrigin, IntPtr content,
+            UIntPtr contentLen, IntPtr payload)
+        {
+            var filePath = FilePathMarshaler.FromNative(delta.NewFile.Path);
+            AddLineChange(this[filePath], lineOrigin);
+
+            return 0;
+        }
+
+        private void AddLineChange(ContentChanges currentChange, GitDiffLineOrigin lineOrigin)
+        {
+            switch (lineOrigin)
+            {
+                case GitDiffLineOrigin.GIT_DIFF_LINE_ADDITION:
+                    linesAdded++;
+                    currentChange.LinesAdded++;
+                    break;
+
+                case GitDiffLineOrigin.GIT_DIFF_LINE_DELETION:
+                    linesDeleted++;
+                    currentChange.LinesDeleted++;
+                    break;
+            }
+        }
+
+        private int PrintCallBack(GitDiffDelta delta, GitDiffRange range, GitDiffLineOrigin lineorigin, IntPtr content, UIntPtr contentlen, IntPtr payload)
+        {
+            string formattedoutput = Utf8Marshaler.FromNative(content, (int)contentlen);
+            var filePath = FilePathMarshaler.FromNative(delta.NewFile.Path);
+
+            fullPatchBuilder.Append(formattedoutput);
+            this[filePath].AppendToPatch(formattedoutput);
+
+            return 0;
+        }
+
+        #region IEnumerable<ContentChanges> Members
+
+        /// <summary>
+        /// Returns an enumerator that iterates through the collection.
+        /// </summary>
+        /// <returns>An <see cref="IEnumerator{T}"/> object that can be used to iterate through the collection.</returns>
+        public virtual IEnumerator<ContentChanges> GetEnumerator()
+        {
+            return changes.Values.GetEnumerator();
+        }
+
+        /// <summary>
+        /// Returns an enumerator that iterates through the collection.
+        /// </summary>
+        /// <returns>An <see cref="IEnumerator"/> object that can be used to iterate through the collection.</returns>
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
+        #endregion
+
+        /// <summary>
+        /// Gets the <see cref="ContentChanges"/> corresponding to the specified <paramref name="path"/>.
+        /// </summary>
+        public virtual ContentChanges this[string path]
+        {
+            get { return this[(FilePath)path]; }
+        }
+
+        private ContentChanges this[FilePath path]
+        {
+            get
+            {
+                ContentChanges contentChanges;
+                if (changes.TryGetValue(path, out contentChanges))
+                {
+                    return contentChanges;
+                }
+
+                return null;
+            }
+        }
+
+        /// <summary>
+        /// The total number of lines added in this diff.
+        /// </summary>
+        public virtual int LinesAdded
+        {
+            get { return linesAdded; }
+        }
+
+        /// <summary>
+        /// The total number of lines added in this diff.
+        /// </summary>
+        public virtual int LinesDeleted
+        {
+            get { return linesDeleted; }
+        }
+
+        /// <summary>
+        /// The full patch file of this diff.
+        /// </summary>
+        public virtual string Content
+        {
+            get { return fullPatchBuilder.ToString(); }
+        }
+
+        /// <summary>
+        /// Implicit operator for string conversion.
+        /// </summary>
+        /// <param name="patch"><see cref="Patch"/>.</param>
+        /// <returns>The patch content as string.</returns>
+        public static implicit operator string(Patch patch)
+        {
+            return patch.fullPatchBuilder.ToString();
+        }
+
+        private string DebuggerDisplay
+        {
+            get
+            {
+                return string.Format(CultureInfo.InvariantCulture,
+                    "+{0} -{1}", linesAdded, linesDeleted);
+            }
+        }
+    }
+}

LibGit2Sharp/Repository.cs

@@ -841,7 +841,7 @@ namespace LibGit2Sharp
 
             Ensure.ArgumentNotNull(commit, "commit");
 
-            TreeChanges changes = Diff.Compare(commit.Tree, DiffTargets.Index, paths, explicitPathsOptions);
+            var changes = Diff.Compare<TreeChanges>(commit.Tree, DiffTargets.Index, paths, explicitPathsOptions);
             Index.Reset(changes);
         }
 

LibGit2Sharp/TreeChanges.cs

@@ -4,7 +4,6 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Globalization;
 using System.Linq;
-using System.Text;
 using LibGit2Sharp.Core;
 using LibGit2Sharp.Core.Handles;
 
@@ -13,6 +12,7 @@ namespace LibGit2Sharp
     /// <summary>
     /// Holds the result of a diff between two trees.
     /// <para>Changes at the granularity of the file can be obtained through the different sub-collections <see cref="Added"/>, <see cref="Deleted"/> and <see cref="Modified"/>.</para>
+    /// <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>
@@ -23,13 +23,9 @@ namespace LibGit2Sharp
         private readonly List<TreeEntryChanges> modified = new List<TreeEntryChanges>();
         private readonly List<TreeEntryChanges> typeChanged = new List<TreeEntryChanges>();
         private readonly List<TreeEntryChanges> unmodified = new List<TreeEntryChanges>();
-        private int linesAdded;
-        private int linesDeleted;
 
         private readonly IDictionary<ChangeKind, Action<TreeChanges, TreeEntryChanges>> fileDispatcher = Build();
 
-        private readonly StringBuilder fullPatchBuilder = new StringBuilder();
-
         private static IDictionary<ChangeKind, Action<TreeChanges, TreeEntryChanges>> Build()
         {
             return new Dictionary<ChangeKind, Action<TreeChanges, TreeEntryChanges>>
@@ -48,23 +44,9 @@ namespace LibGit2Sharp
         protected TreeChanges()
         { }
 
-        internal TreeChanges(DiffListSafeHandle diff, bool skipPatchBuilding = false)
+        internal TreeChanges(DiffListSafeHandle diff)
         {
-            Proxy.git_diff_foreach(diff, FileCallback, null, DataCallback);
-
-            if (!skipPatchBuilding)
-            {
-                Proxy.git_diff_print_patch(diff, PrintCallBack);
-            }
-        }
-
-        private int DataCallback(GitDiffDelta delta, GitDiffRange range, GitDiffLineOrigin lineOrigin, IntPtr content, UIntPtr contentLen, IntPtr payload)
-        {
-            var filePath = FilePathMarshaler.FromNative(delta.NewFile.Path);
-
-            AddLineChange(this[filePath], lineOrigin);
-
-            return 0;
+            Proxy.git_diff_foreach(diff, FileCallback, null, null);
         }
 
         private int FileCallback(GitDiffDelta delta, float progress, IntPtr payload)
@@ -73,33 +55,6 @@ namespace LibGit2Sharp
             return 0;
         }
 
-        private int PrintCallBack(GitDiffDelta delta, GitDiffRange range, GitDiffLineOrigin lineorigin, IntPtr content, UIntPtr contentlen, IntPtr payload)
-        {
-            string formattedoutput = Utf8Marshaler.FromNative(content, (int)contentlen);
-            var filePath = FilePathMarshaler.FromNative(delta.NewFile.Path);
-
-            fullPatchBuilder.Append(formattedoutput);
-            this[filePath].AppendToPatch(formattedoutput);
-
-            return 0;
-        }
-
-        private void AddLineChange(Changes currentChange, GitDiffLineOrigin lineOrigin)
-        {
-            switch (lineOrigin)
-            {
-                case GitDiffLineOrigin.GIT_DIFF_LINE_ADDITION:
-                    linesAdded++;
-                    currentChange.LinesAdded++;
-                    break;
-
-                case GitDiffLineOrigin.GIT_DIFF_LINE_DELETION:
-                    linesDeleted++;
-                    currentChange.LinesDeleted++;
-                    break;
-            }
-        }
-
         private void AddFileChange(GitDiffDelta delta)
         {
             var newFilePath = FilePathMarshaler.FromNative(delta.NewFile.Path);
@@ -115,13 +70,13 @@ namespace LibGit2Sharp
                 delta.Status = ChangeKind.Added;
             }
 
-            var diffFile = new TreeEntryChanges(newFilePath, newMode, newOid, delta.Status, oldFilePath, oldMode, oldOid, delta.IsBinary());
+            var diffFile = new TreeEntryChanges(newFilePath, newMode, newOid, delta.Status, oldFilePath, oldMode, oldOid);
 
             fileDispatcher[delta.Status](this, diffFile);
             changes.Add(newFilePath, diffFile);
         }
 
-        #region IEnumerable<Tag> Members
+        #region IEnumerable<TreeEntryChanges> Members
 
         /// <summary>
         /// Returns an enumerator that iterates through the collection.
@@ -197,30 +152,6 @@ namespace LibGit2Sharp
             get { return typeChanged; }
         }
 
-        /// <summary>
-        /// The total number of lines added in this diff.
-        /// </summary>
-        public virtual int LinesAdded
-        {
-            get { return linesAdded; }
-        }
-
-        /// <summary>
-        /// The total number of lines added in this diff.
-        /// </summary>
-        public virtual int LinesDeleted
-        {
-            get { return linesDeleted; }
-        }
-
-        /// <summary>
-        /// The full patch file of this diff.
-        /// </summary>
-        public virtual string Patch
-        {
-            get { return fullPatchBuilder.ToString(); }
-        }
-
         private string DebuggerDisplay
         {
             get

LibGit2Sharp/TreeEntryChanges.cs

@@ -8,7 +8,7 @@ namespace LibGit2Sharp
     /// Holds the changes between two versions of a tree entry.
     /// </summary>
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
-    public class TreeEntryChanges : Changes
+    public class TreeEntryChanges
     {
         /// <summary>
         /// Needed for mocking purposes.
@@ -16,7 +16,7 @@ namespace LibGit2Sharp
         protected TreeEntryChanges()
         { }
 
-        internal TreeEntryChanges(FilePath path, Mode mode, ObjectId oid, ChangeKind status, FilePath oldPath, Mode oldMode, ObjectId oldOid, bool isBinaryComparison)
+        internal TreeEntryChanges(FilePath path, Mode mode, ObjectId oid, ChangeKind status, FilePath oldPath, Mode oldMode, ObjectId oldOid)
         {
             Path = path.Native;
             Mode = mode;
@@ -25,7 +25,6 @@ namespace LibGit2Sharp
             OldPath = oldPath.Native;
             OldMode = oldMode;
             OldOid = oldOid;
-            IsBinaryComparison = isBinaryComparison;
         }
 
         /// <summary>