Stop assuming ODB backend includes wrapping routine; wrap in git2go instead

odb.go

@@ -17,6 +17,10 @@ type Odb struct {
 	ptr *C.git_odb
 }
 
+type OdbBackend struct {
+  ptr *C.git_odb_backend
+}
+
 func (v *Odb) Exists(oid *Oid) bool {
 	ret := C.git_odb_exists(v.ptr, oid.toC())
 	return ret != 0

repository.go

@@ -15,7 +15,7 @@ type Repository struct {
 	ptr *C.git_repository
 }
 
-type InitCustomBackend func(**C.git_repository, **C.git_odb) int
+type InitCustomBackend func(**C.git_odb_backend) int
 
 func OpenRepository(path string) (*Repository, error) {
 	repo := new(Repository)
@@ -47,18 +47,31 @@ func InitRepository(path string, isbare bool) (*Repository, error) {
 	return repo, nil
 }
 
-func InitRepositoryWCustomOdbBackend(initStrategy InitCustomBackend) (*Repository, *Odb, error) {
-	// init return vars
+func InitRepositoryWCustomOdbBackend(initStrategy InitCustomBackend, priority int) (*Repository, *Odb, error) {
+	// inits
 	repo := new(Repository)
 	odb := new(Odb)
+	backend := new(OdbBackend)
 
-  // run initStrategy abstract function
-	ret := initStrategy(&repo.ptr, &odb.ptr)
+	// wrap routine w/abstract function
+	ret := C.git_odb_new(&odb.ptr)
+	if ret >= 0 {
+		ret = C.git_repository_wrap_odb(&repo.ptr, odb.ptr)
+	}
+
+	if ret >= 0 {
+		ret = C.int(initStrategy(&backend.ptr))
+	}
+
+	if ret >= 0 {
+		ret = C.git_odb_add_backend(odb.ptr, backend.ptr, C.int(priority))
+	}
+
+	// cleanup and return
 	if ret < 0 {
 		return nil, nil, LastError()
 	}
 
-	// cleanup and return
 	runtime.SetFinalizer(repo, (*Repository).Free)
 	runtime.SetFinalizer(odb, (*Odb).Free)
 	return repo, odb, nil