Add git_reference_lookup_oid and lookup_resolved

Adds a new public reference function `git_reference_lookup_oid`
that directly resolved a reference name to an OID without returning
the intermediate `git_reference` object (hence, no free needed).

Internally, this adds a `git_reference_lookup_resolved` function
that combines looking up and resolving a reference.  This allows
us to be more efficient with memory reallocation.

The existing `git_reference_lookup` and `git_reference_resolve`
are reimplmented on top of the new utility and a few places in the
code are changed to use one of the two new functions.

1 files changed, 42 insertions, 0 deletions

diff --git a/tests-clar/refs/lookup.c b/tests-clar/refs/lookup.c
new file mode 100644
index 000000000..d9b6c260f
--- /dev/null
+++ b/tests-clar/refs/lookup.c
@@ -0,0 +1,42 @@
+#include "clar_libgit2.h"
+#include "refs.h"
+
+static git_repository *g_repo;
+
+void test_refs_lookup__initialize(void)
+{
+	g_repo = cl_git_sandbox_init("testrepo.git");
+}
+
+void test_refs_lookup__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+void test_refs_lookup__with_resolve(void)
+{
+	git_reference *a, *b, *temp;
+
+	cl_git_pass(git_reference_lookup(&temp, g_repo, "HEAD"));
+	cl_git_pass(git_reference_resolve(&a, temp));
+	git_reference_free(temp);
+
+	cl_git_pass(git_reference_lookup_resolved(&b, g_repo, "HEAD", 5));
+	cl_assert(git_reference_cmp(a, b) == 0);
+	git_reference_free(b);
+
+	cl_git_pass(git_reference_lookup_resolved(&b, g_repo, "head-tracker", 5));
+	cl_assert(git_reference_cmp(a, b) == 0);
+	git_reference_free(b);
+
+	git_reference_free(a);
+}
+
+void test_refs_lookup__oid(void)
+{
+	git_oid tag, expected;
+
+	cl_git_pass(git_reference_lookup_oid(&tag, g_repo, "refs/tags/point_to_blob"));
+	cl_git_pass(git_oid_fromstr(&expected, "1385f264afb75a56a5bec74243be9b367ba4ca08"));
+	cl_assert(git_oid_cmp(&tag, &expected) == 0);
+}