Add Repository.ObjectDatabase.CreateCommit()

Partially fixes #127.

3 files changed, 74 insertions, 26 deletions

diff --git a/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs b/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs
index f7b83f42..5102f616 100644
--- a/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs
+++ b/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs
@@ -182,5 +182,28 @@ namespace LibGit2Sharp.Tests
                 Assert.Equal("dc53d4c6b8684c21b0b57db29da4a2afea011565", td["1/2/another new file"].TargetId.Sha);
             }
         }
+
+        [Fact]
+        public void CanCreateACommit()
+        {
+            TemporaryCloneOfTestRepo scd = BuildTemporaryCloneOfTestRepo();
+
+            using (var repo = new Repository(scd.RepositoryPath))
+            {
+                Branch head = repo.Head;
+
+                TreeDefinition td = TreeDefinition.From(repo.Head.Tip.Tree);
+                td.Add("1/2/readme", td["README"]);
+
+                Tree tree = repo.ObjectDatabase.CreateTree(td);
+
+                Commit commit = repo.ObjectDatabase.CreateCommit("message", DummySignature, DummySignature, tree, new[] { repo.Head.Tip });
+
+                Branch newHead = repo.Head;
+
+                Assert.Equal(head, newHead);
+                Assert.Equal(commit, repo.Lookup<Commit>(commit.Sha));
+            }
+        }
     }
 }
diff --git a/LibGit2Sharp/CommitCollection.cs b/LibGit2Sharp/CommitCollection.cs
index 1853a987..4c8698d9 100644
--- a/LibGit2Sharp/CommitCollection.cs
+++ b/LibGit2Sharp/CommitCollection.cs
@@ -134,51 +134,33 @@ namespace LibGit2Sharp
         /// <returns>The generated <see cref = "Commit" />.</returns>
         public Commit Create(string message, Signature author, Signature committer, bool amendPreviousCommit)
         {
-            Ensure.ArgumentNotNull(message, "message");
-            Ensure.ArgumentNotNull(author, "author");
-            Ensure.ArgumentNotNull(committer, "committer");
-
             if (amendPreviousCommit && repo.Info.IsEmpty)
             {
                 throw new LibGit2Exception("Can not amend anything. The Head doesn't point at any commit.");
             }
 
             GitOid treeOid;
-            int res = NativeMethods.git_tree_create_fromindex(out treeOid, repo.Index.Handle);
-            Ensure.Success(res);
-
-            var parentIds = RetrieveParentIdsOfTheCommitBeingCreated(repo, amendPreviousCommit);
-
-            GitOid commitOid;
-            using (var treePtr = new ObjectSafeWrapper(new ObjectId(treeOid), repo))
-            using (var parentObjectPtrs = new DisposableEnumerable<ObjectSafeWrapper>(parentIds.Select(id => new ObjectSafeWrapper(id, repo))))
-            using (SignatureSafeHandle authorHandle = author.BuildHandle())
-            using (SignatureSafeHandle committerHandle = committer.BuildHandle())
-            {
-                string encoding = null; //TODO: Handle the encoding of the commit to be created
+            Ensure.Success(NativeMethods.git_tree_create_fromindex(out treeOid, repo.Index.Handle));
+            var tree = repo.Lookup<Tree>(new ObjectId(treeOid));
 
-                IntPtr[] parentsPtrs = parentObjectPtrs.Select(o => o.ObjectPtr.DangerousGetHandle() ).ToArray();
-                res = NativeMethods.git_commit_create(out commitOid, repo.Handle, repo.Refs["HEAD"].CanonicalName, authorHandle,
-                                                      committerHandle, encoding, message, treePtr.ObjectPtr, parentObjectPtrs.Count(), parentsPtrs);
-                Ensure.Success(res);
-            }
+            var parents = RetrieveParentsOfTheCommitBeingCreated(repo, amendPreviousCommit);
 
-            return repo.Lookup<Commit>(new ObjectId(commitOid));
+            return repo.ObjectDatabase.CreateCommit(message, author, committer, tree, parents, "HEAD");
         }
 
-        private static IEnumerable<ObjectId> RetrieveParentIdsOfTheCommitBeingCreated(Repository repo, bool amendPreviousCommit)
+        private static IEnumerable<Commit> RetrieveParentsOfTheCommitBeingCreated(Repository repo, bool amendPreviousCommit)
         {
             if (amendPreviousCommit)
             {
-                return repo.Head.Tip.Parents.Select(c => c.Id);
+                return repo.Head.Tip.Parents;
             }
 
             if (repo.Info.IsEmpty)
             {
-                return Enumerable.Empty<ObjectId>();
+                return Enumerable.Empty<Commit>();
             }
 
-            return new[] { repo.Head.Tip.Id };
+            return new[] { repo.Head.Tip };
         }
 
         private class CommitEnumerator : IEnumerator<Commit>
diff --git a/LibGit2Sharp/ObjectDatabase.cs b/LibGit2Sharp/ObjectDatabase.cs
index 1a430440..dfaf565d 100644
--- a/LibGit2Sharp/ObjectDatabase.cs
+++ b/LibGit2Sharp/ObjectDatabase.cs
@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using LibGit2Sharp.Core;
 using LibGit2Sharp.Core.Handles;
 
@@ -59,5 +61,46 @@ namespace LibGit2Sharp
         {
             return treeDefinition.Build(repo);
         }
+
+        /// <summary>
+        ///   Inserts a <see cref = "Commit"/> into the object database, referencing an existing <see cref = "Tree"/>.
+        /// </summary>
+        /// <param name = "message">The description of why a change was made to the repository.</param>
+        /// <param name = "author">The <see cref = "Signature" /> of who made the change.</param>
+        /// <param name = "committer">The <see cref = "Signature" /> of who added the change to the repository.</param>
+        /// <param name = "tree">The <see cref = "Tree"/> of the <see cref = "Commit"/> to be created.</param>
+        /// <param name = "parents">The parents of the <see cref = "Commit"/> to be created.</param>
+        /// <returns>The created <see cref = "Commit"/>.</returns>
+        public Commit CreateCommit(string message, Signature author, Signature committer, Tree tree, IEnumerable<Commit> parents)
+        {
+            return CreateCommit(message, author, committer, tree, parents, null);
+        }
+
+        internal Commit CreateCommit(string message, Signature author, Signature committer, Tree tree, IEnumerable<Commit> parents, string referenceName)
+        {
+            Ensure.ArgumentNotNull(message, "message");
+            Ensure.ArgumentNotNull(author, "author");
+            Ensure.ArgumentNotNull(committer, "committer");
+            Ensure.ArgumentNotNull(tree, "tree");
+            Ensure.ArgumentNotNull(parents, "parents");
+
+            IEnumerable<ObjectId> parentIds = parents.Select(p => p.Id);
+
+            GitOid commitOid;
+            using (var treePtr = new ObjectSafeWrapper(tree.Id, repo))
+            using (var parentObjectPtrs = new DisposableEnumerable<ObjectSafeWrapper>(parentIds.Select(id => new ObjectSafeWrapper(id, repo))))
+            using (SignatureSafeHandle authorHandle = author.BuildHandle())
+            using (SignatureSafeHandle committerHandle = committer.BuildHandle())
+            {
+                string encoding = null; //TODO: Handle the encoding of the commit to be created
+
+                IntPtr[] parentsPtrs = parentObjectPtrs.Select(o => o.ObjectPtr.DangerousGetHandle()).ToArray();
+                int res = NativeMethods.git_commit_create(out commitOid, repo.Handle, referenceName, authorHandle,
+                                                      committerHandle, encoding, message, treePtr.ObjectPtr, parentObjectPtrs.Count(), parentsPtrs);
+                Ensure.Success(res);
+            }
+
+            return repo.Lookup<Commit>(new ObjectId(commitOid));
+        }
     }
 }