repository: Add git_repository_head()

include/git2/repository.h

@@ -219,6 +219,16 @@ GIT_EXTERN(void) git_repository_free(git_repository *repo);
 GIT_EXTERN(int) git_repository_init(git_repository **repo_out, const char *path, unsigned is_bare);
 
 /**
+ * Retrieve and resolve the reference pointed at by HEAD.
+ *
+ * @param head_out pointer to the reference which will be retrieved
+ * @param repo a repository object
+ *
+ * @return 0 on success; error code otherwise
+ */
+GIT_EXTERN(int) git_repository_head(git_reference **head_out, git_repository *repo);
+
+/**
  * Check if a repository's HEAD is detached
  *
  * A repository's HEAD is detached when it points directly to a commit

src/repository.c

@@ -729,19 +729,31 @@ int git_repository_head_detached(git_repository *repo)
 	return 1;
 }
 
-int git_repository_head_orphan(git_repository *repo)
+int git_repository_head(git_reference **head_out, git_repository *repo)
 {
 	git_reference *ref;
 	int error;
 
+	*head_out = NULL;
+
 	error = git_reference_lookup(&ref, repo, GIT_HEAD_FILE);
 	if (error < GIT_SUCCESS)
-		return error;
-
-	if (git_reference_type(ref) == GIT_REF_OID)
-		return 0;
+		return git__rethrow(GIT_ENOTAREPO, "Failed to locate the HEAD");
 
 	error = git_reference_resolve(&ref, ref);
+	if (error < GIT_SUCCESS)
+		return git__rethrow(error, "Failed to resolve the HEAD");
+
+	*head_out = ref;
+	return GIT_SUCCESS;
+}
+
+int git_repository_head_orphan(git_repository *repo)
+{
+	git_reference *ref;
+	int error;
+
+	error = git_repository_head(&ref, repo);
 
 	return error == GIT_ENOTFOUND ? 1 : error;
 }