Implement ref lookups for custom refdb backends.

Author: arthurschreiber

ext/rugged/rugged_refdb_backend_custom.c

@@ -45,6 +45,30 @@ static int rugged_refdb_backend_custom__exists(
 	return GIT_OK;
 }
 
+static int rugged_refdb_backend_custom__lookup(
+	git_reference **out,
+	git_refdb_backend *_backend,
+	const char *ref_name)
+{
+	rugged_refdb_backend_custom *backend = (rugged_refdb_backend_custom *)_backend;
+	git_oid oid;
+	VALUE rb_result;
+
+	// TODO: Proper exception handling
+	rb_result = rb_funcall(backend->self, rb_intern("lookup"), 1, rb_str_new2(ref_name));
+	if (TYPE(rb_result) == T_STRING) {
+		// TODO: Handle symbolic refs as well
+		// TODO: Proper exception handling
+		rugged_exception_check(git_oid_fromstr(&oid, StringValueCStr(rb_result)));
+		*out = git_reference__alloc(ref_name, &oid, NULL);
+		return GIT_OK;
+	} else {
+		// TODO: Better error handling
+		*out = NULL;
+		return GIT_ENOTFOUND;
+	}
+}
+
 static int rugged_refdb_backend_custom__compress(git_refdb_backend *_backend)
 {
 	rugged_refdb_backend_custom *backend = (rugged_refdb_backend_custom *)_backend;
@@ -68,6 +92,7 @@ static VALUE rb_git_refdb_backend_custom_new(VALUE self, VALUE rb_repo)
 
 	backend->parent.exists = &rugged_refdb_backend_custom__exists;
 	backend->parent.compress = &rugged_refdb_backend_custom__compress;
+	backend->parent.lookup = &rugged_refdb_backend_custom__lookup;
 	backend->parent.free = xfree;
 
 	backend->self = Data_Wrap_Struct(self, NULL, rb_git_refdb_backend__free, backend);

test/refdb_test.rb

@@ -40,3 +40,26 @@ def test_custom_backend
     assert_equal 1, compress_calls
   end
 end
+
+class RefdbBackendCustomTest < Rugged::TestCase
+  def setup
+    @repo = FixtureRepo.from_rugged("testrepo.git")
+    @refdb = Rugged::Refdb.new(@repo)
+    @backend = Rugged::Refdb::Backend::Custom.new(@repo)
+    @refdb.backend = @backend
+    @repo.refdb = @refdb
+  end
+
+  def test_lookup
+    @backend.send(:define_singleton_method, :lookup) do |ref_name|
+      "1385f264afb75a56a5bec74243be9b367ba4ca08" if ref_name == "refs/heads/master"
+    end
+
+    ref = @repo.references["refs/heads/master"]
+    assert ref
+    assert_equal "refs/heads/master", ref.name
+    assert_equal "1385f264afb75a56a5bec74243be9b367ba4ca08", ref.target_id
+
+    assert_nil @repo.references["refs/heads/development"]
+  end
+end