Introduce Repository.MergeHeads

7 files changed, 102 insertions, 1 deletions

diff --git a/LibGit2Sharp.Tests/MergeFixture.cs b/LibGit2Sharp.Tests/MergeFixture.cs
index f7ecd1cb..0c7285b7 100644
--- a/LibGit2Sharp.Tests/MergeFixture.cs
+++ b/LibGit2Sharp.Tests/MergeFixture.cs
@@ -1,4 +1,6 @@
-using System.Linq;
+using System;
+using System.IO;
+using System.Linq;
 using LibGit2Sharp.Tests.TestHelpers;
 using Xunit;
 
@@ -13,6 +15,7 @@ namespace LibGit2Sharp.Tests
             using (var repo = Repository.Init(scd.DirectoryPath))
             {
                 Assert.Equal(true, repo.Index.IsFullyMerged);
+                Assert.Empty(repo.MergeHeads);
             }
         }
 
@@ -22,6 +25,7 @@ namespace LibGit2Sharp.Tests
             using (var repo = new Repository(StandardTestRepoWorkingDirPath))
             {
                 Assert.Equal(true, repo.Index.IsFullyMerged);
+                Assert.Empty(repo.MergeHeads);
 
                 foreach (var entry in repo.Index)
                 {
@@ -56,5 +60,28 @@ namespace LibGit2Sharp.Tests
                     () => repo.Commit("Try commit unmerged entries", author, author));
             }
         }
+
+        [Fact]
+        public void CanRetrieveTheBranchBeingMerged()
+        {
+            TemporaryCloneOfTestRepo path = BuildTemporaryCloneOfTestRepo(StandardTestRepoPath);
+            using (var repo = new Repository(path.RepositoryPath))
+            {
+                const string firstBranch = "9fd738e8f7967c078dceed8190330fc8648ee56a";
+                const string secondBranch = "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef";
+
+                string mergeHeadPath = Path.Combine(repo.Info.Path, "MERGE_HEAD");
+                File.WriteAllText(mergeHeadPath, 
+                    string.Format("{0}{1}{2}{1}", firstBranch, "\n", secondBranch));
+
+                Assert.Equal(CurrentOperation.Merge, repo.Info.CurrentOperation);
+
+                MergeHead[] mergedHeads = repo.MergeHeads.ToArray();
+                Assert.Equal("MERGE_HEAD[0]", mergedHeads[0].Name);
+                Assert.Equal(firstBranch, mergedHeads[0].Tip.Id.Sha);
+                Assert.Equal("MERGE_HEAD[1]", mergedHeads[1].Name);
+                Assert.Null(mergedHeads[1].Tip);
+            }
+        }
     }
 }
diff --git a/LibGit2Sharp/Core/NativeMethods.cs b/LibGit2Sharp/Core/NativeMethods.cs
index be258557..c1aaa72b 100644
--- a/LibGit2Sharp/Core/NativeMethods.cs
+++ b/LibGit2Sharp/Core/NativeMethods.cs
@@ -742,6 +742,16 @@ namespace LibGit2Sharp.Core
         [DllImport(libgit2)]
         internal static extern int git_repository_is_empty(RepositorySafeHandle repo);
 
+        internal delegate int git_repository_mergehead_foreach_cb(
+            ref GitOid oid,
+            IntPtr payload);
+
+        [DllImport(libgit2)]
+        internal static extern int git_repository_mergehead_foreach(
+            RepositorySafeHandle repo,
+            git_repository_mergehead_foreach_cb cb,
+            IntPtr payload);
+
         [DllImport(libgit2)]
         internal static extern int git_repository_open(
             out RepositorySafeHandle repository,
diff --git a/LibGit2Sharp/Core/Proxy.cs b/LibGit2Sharp/Core/Proxy.cs
index 8b7d1dbc..4e0ff57d 100644
--- a/LibGit2Sharp/Core/Proxy.cs
+++ b/LibGit2Sharp/Core/Proxy.cs
@@ -1384,6 +1384,17 @@ namespace LibGit2Sharp.Core
             return RepositoryStateChecker(repo, NativeMethods.git_repository_is_empty);
         }
 
+        public static ICollection<TResult> git_repository_mergehead_foreach<TResult>(
+            RepositorySafeHandle repo,
+            Func<GitOid, TResult> resultSelector)
+        {
+            return git_foreach(
+                resultSelector,
+                c => NativeMethods.git_repository_mergehead_foreach(
+                    repo, (ref GitOid x, IntPtr p) => c(x, p), IntPtr.Zero),
+                GitErrorCode.NotFound);
+        }
+
         public static ObjectDatabaseSafeHandle git_repository_odb(RepositorySafeHandle repo)
         {
             using (ThreadAffinity())
diff --git a/LibGit2Sharp/IRepository.cs b/LibGit2Sharp/IRepository.cs
index 7c108e7a..b21820e9 100644
--- a/LibGit2Sharp/IRepository.cs
+++ b/LibGit2Sharp/IRepository.cs
@@ -136,5 +136,10 @@ namespace LibGit2Sharp
         /// Clean the working tree by removing files that are not under version control.
         /// </summary>
         void RemoveUntrackedFiles();
+
+        /// <summary>
+        ///   Gets the references to the tips that are currently being merged.
+        /// </summary>
+        IEnumerable<MergeHead> MergeHeads { get; }
     }
 }
diff --git a/LibGit2Sharp/LibGit2Sharp.csproj b/LibGit2Sharp/LibGit2Sharp.csproj
index d9723b04..38be381e 100644
--- a/LibGit2Sharp/LibGit2Sharp.csproj
+++ b/LibGit2Sharp/LibGit2Sharp.csproj
@@ -92,6 +92,7 @@
     <Compile Include="Handlers.cs" />
     <Compile Include="Ignore.cs" />
     <Compile Include="MergeConflictException.cs" />
+    <Compile Include="MergeHead.cs" />
     <Compile Include="NameConflictException.cs" />
     <Compile Include="ReferenceCollectionExtensions.cs" />
     <Compile Include="Core\GitRemoteCallbacks.cs" />
diff --git a/LibGit2Sharp/MergeHead.cs b/LibGit2Sharp/MergeHead.cs
new file mode 100644
index 00000000..38b19622
--- /dev/null
+++ b/LibGit2Sharp/MergeHead.cs
@@ -0,0 +1,34 @@
+using System.Globalization;
+
+namespace LibGit2Sharp
+{
+    /// <summary>
+    ///   A merge head is a parent for the next commit.
+    /// </summary>
+    public class MergeHead : ReferenceWrapper<Commit>
+    {
+        /// <summary>
+        ///   Needed for mocking purposes.
+        /// </summary>
+        protected MergeHead()
+        { }
+
+        internal MergeHead(Repository repo, ObjectId targetId, int index)
+            : base(repo, new DirectReference(string.Format(CultureInfo.InvariantCulture, "MERGE_HEAD[{0}]", index), repo, targetId), r => r.CanonicalName)
+        {
+        }
+
+        /// <summary>
+        ///   Gets the <see cref="Commit"/> that this merge head points to.
+        /// </summary>
+        public virtual Commit Tip
+        {
+            get { return TargetObject; }
+        }
+
+        protected override string Shorten()
+        {
+            return CanonicalName;
+        }
+    }
+}
diff --git a/LibGit2Sharp/Repository.cs b/LibGit2Sharp/Repository.cs
index 323e2a63..1faaa9a3 100644
--- a/LibGit2Sharp/Repository.cs
+++ b/LibGit2Sharp/Repository.cs
@@ -709,6 +709,19 @@ namespace LibGit2Sharp
             }
         }
 
+        /// <summary>
+        ///   Gets the references to the tips that are currently being merged.
+        /// </summary>
+        public virtual IEnumerable<MergeHead> MergeHeads
+        {
+            get
+            {
+                int i = 0;
+                return Proxy.git_repository_mergehead_foreach(Handle,
+                    commitId => new MergeHead(this, new ObjectId(commitId), i++));
+            }
+        }
+
         private string DebuggerDisplay
         {
             get