add OdbBackend.Free() and the C it wraps; go fmt odb.go

odb.go

@@ -5,12 +5,13 @@ package git
 #include <git2/errors.h>
 
 extern int _go_git_odb_foreach(git_odb *db, void *payload);
+extern void _go_git_odb_backend_free(git_odb_backend *backend);
 */
 import "C"
 import (
-	"unsafe"
 	"reflect"
 	"runtime"
+	"unsafe"
 )
 
 type Odb struct {
@@ -38,10 +39,10 @@ func NewOdbBackendFromC(ptr *C.git_odb_backend) (backend *OdbBackend) {
 	return
 }
 
-
 func (v *Odb) AddBackend(backend *OdbBackend, priority int) (err error) {
 	ret := C.git_odb_add_backend(v.ptr, backend.ptr, C.int(priority))
 	if ret < 0 {
+		backend.Free()
 		err = LastError()
 	}
 	return nil
@@ -95,7 +96,7 @@ func odbForEachCb(id *C.git_oid, payload unsafe.Pointer) int {
 	case <-ch:
 		return -1
 	}
-	return 0;
+	return 0
 }
 
 func (v *Odb) forEachWrap(ch chan *Oid) {
@@ -136,6 +137,10 @@ func (v *Odb) NewWriteStream(size int, otype ObjectType) (*OdbWriteStream, error
 	return stream, nil
 }
 
+func (v *OdbBackend) Free() {
+	C._go_git_odb_backend_free(v.ptr)
+}
+
 type OdbObject struct {
 	ptr *C.git_odb_object
 }

wrapper.c

@@ -1,5 +1,6 @@
 #include "_cgo_export.h"
 #include "git2.h"
+#include "git2/sys/odb_backend.h"
 #include "git2/submodule.h"
 #include "git2/pack.h"
 
@@ -24,4 +25,12 @@ int _go_git_odb_foreach(git_odb *db, void *payload)
 {
     return git_odb_foreach(db, (git_odb_foreach_cb)&odbForEachCb, payload);
 }
+
+void _go_git_odb_backend_free(git_odb_backend *backend)
+{
+    if (backend->free)
+      backend->free(backend);
+
+    return;
+}
 /* EOF */