1 files changed, 59 insertions, 0 deletions
diff --git a/src/refs.c b/src/refs.c
index 1ef3e13a4..104685793 100644
--- a/src/refs.c
+++ b/src/refs.c
@@ -1705,3 +1705,62 @@ int git_reference_cmp(git_reference *ref1, git_reference *ref2)
 	return git_oid_cmp(&ref1->target.oid, &ref2->target.oid);
 }
 
+/* Update the reference named `ref_name` so it points to `oid` */
+int git_reference__update(git_repository *repo, const git_oid *oid, const char *ref_name)
+{
+	git_reference *ref;
+	int res;
+
+	res = git_reference_lookup(&ref, repo, ref_name);
+
+	/* If we haven't found the reference at all, we assume we need to create
+	 * a new reference and that's it */
+	if (res == GIT_ENOTFOUND) {
+		giterr_clear();
+		return git_reference_create_oid(NULL, repo, ref_name, oid, 1);
+	}
+
+	if (res < 0)
+		return -1;
+
+	/* If we have found a reference, but it's symbolic, we need to update
+	 * the direct reference it points to */
+	if (git_reference_type(ref) == GIT_REF_SYMBOLIC) {
+		git_reference *aux;
+		const char *sym_target;
+
+		/* The target pointed at by this reference */
+		sym_target = git_reference_target(ref);
+
+		/* resolve the reference to the target it points to */
+		res = git_reference_resolve(&aux, ref);
+
+		/*
+		 * if the symbolic reference pointed to an inexisting ref,
+		 * this is means we're creating a new branch, for example.
+		 * We need to create a new direct reference with that name
+		 */
+		if (res == GIT_ENOTFOUND) {
+			giterr_clear();
+			res = git_reference_create_oid(NULL, repo, sym_target, oid, 1);
+			git_reference_free(ref);
+			return res;
+		}
+
+		/* free the original symbolic reference now; not before because
+		 * we're using the `sym_target` pointer */
+		git_reference_free(ref);
+
+		if (res < 0)
+			return -1;
+
+		/* store the newly found direct reference in its place */
+		ref = aux;
+	}
+
+	/* ref is made to point to `oid`: ref is either the original reference,
+	 * or the target of the symbolic reference we've looked up */
+	res = git_reference_set_oid(ref, oid);
+	git_reference_free(ref);
+	return res;
+}