merge: expose multiple merge basescmn/oidarray

We always calculate multiple merge bases, but up to now we had only
exposed the "best" merge base.

Introduce git_oidarray which analogously to git_strarray lets us return
multiple ids.

2 files changed, 56 insertions, 0 deletions

diff --git a/include/git2/merge.h b/include/git2/merge.h
index 9eb14ccb1..bd5ebc1bd 100644
--- a/include/git2/merge.h
+++ b/include/git2/merge.h
@@ -10,6 +10,7 @@
 #include "common.h"
 #include "types.h"
 #include "oid.h"
+#include "oidarray.h"
 #include "checkout.h"
 #include "index.h"
 
@@ -321,6 +322,21 @@ GIT_EXTERN(int) git_merge_base(
 	const git_oid *two);
 
 /**
+ * Find merge bases between two commits
+ *
+ * @param out array in which to store the resulting ids
+ * @param repo the repository where the commits exist
+ * @param one one of the commits
+ * @param two the other commit
+ * @return 0 on success, GIT_ENOTFOUND if not found or error code
+ */
+GIT_EXTERN(int) git_merge_bases(
+	git_oidarray *out,
+	git_repository *repo,
+	const git_oid *one,
+	const git_oid *two);
+
+/**
  * Find a merge base given a list of commits
  *
  * @param out the OID of a merge base considering all the commits
diff --git a/include/git2/oidarray.h b/include/git2/oidarray.h
new file mode 100644
index 000000000..0b3204597
--- /dev/null
+++ b/include/git2/oidarray.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_git_oidarray_h__
+#define INCLUDE_git_oidarray_h__
+
+#include "common.h"
+#include "oid.h"
+
+GIT_BEGIN_DECL
+
+/** Array of object ids */
+typedef struct git_oidarray {
+	git_oid *ids;
+	size_t count;
+} git_oidarray;
+
+/**
+ * Free the OID array
+ *
+ * This method must (and must only) be called on `git_oidarray`
+ * objects where the array is allocated by the library. Not doing so,
+ * will result in a memory leak.
+ *
+ * This does not free the `git_oidarray` itself, since the library will
+ * never allocate that object directly itself (it is more commonly embedded
+ * inside another struct or created on the stack).
+ *
+ * @param array git_oidarray from which to free oid data
+ */
+GIT_EXTERN(void) git_oidarray_free(git_oidarray *array);
+
+/** @} */
+GIT_END_DECL
+
+#endif
+