1 files changed, 77 insertions, 0 deletions
diff --git a/git.go b/git.go
index 68712d4..d8cacc4 100644
--- a/git.go
+++ b/git.go
@@ -7,7 +7,11 @@ package git
 */
 import "C"
 import (
+	"bytes"
+	"errors"
 	"unsafe"
+	"strings"
+	"fmt"
 )
 
 const (
@@ -16,6 +20,10 @@ const (
 	ENOTFOUND = C.GIT_ENOTFOUND
 )
 
+var (
+	ErrIterOver = errors.New("Iteration is over")
+)
+
 func init() {
 	C.git_threads_init()
 }
@@ -67,6 +75,53 @@ func (oid *Oid) Bytes() []byte {
 	return oid.bytes[0:]
 }
 
+func (oid *Oid) Cmp(oid2 *Oid) int {
+	return bytes.Compare(oid.bytes[:], oid2.bytes[:])
+}
+
+func (oid *Oid) Copy() *Oid {
+	ret := new(Oid)
+	copy(ret.bytes[:], oid.bytes[:])
+	return ret
+}
+
+func (oid *Oid) Equal(oid2 *Oid) bool {
+	return bytes.Equal(oid.bytes[:], oid2.bytes[:])
+}
+
+func (oid *Oid) IsZero() bool {
+	for _, a := range(oid.bytes) {
+		if a != '0' {
+			return false
+		}
+	}
+	return true
+}
+
+func (oid *Oid) NCmp(oid2 *Oid, n uint) int {
+	return bytes.Compare(oid.bytes[:n], oid2.bytes[:n])
+}
+
+func ShortenOids(ids []*Oid, minlen int) (int, error) {
+	shorten := C.git_oid_shorten_new(C.size_t(minlen))
+	if shorten == nil {
+		panic("Out of memory")
+	}
+	defer C.git_oid_shorten_free(shorten)
+
+	var ret C.int
+	for _, id := range ids {
+		buf := make([]byte, 41)
+		C.git_oid_fmt((*C.char)(unsafe.Pointer(&buf[0])), id.toC())
+		buf[40] = 0
+		ret = C.git_oid_shorten_add(shorten, (*C.char)(unsafe.Pointer(&buf[0])))
+		if ret < 0 {
+			return int(ret), LastError()
+		}
+	}
+	return int(ret), nil
+}
+
 type GitError struct {
 	Message string
 	Code int
@@ -78,6 +133,9 @@ func (e GitError) Error() string{
 
 func LastError() error {
 	err := C.giterr_last()
+	if err == nil {
+		return &GitError{"No message", 0}
+	}
 	return &GitError{C.GoString(err.message), int(err.klass)}
 }
 
@@ -94,3 +152,22 @@ func ucbool(b bool) C.uint {
 	}
 	return C.uint(0)
 }
+
+func Discover(start string, across_fs bool, ceiling_dirs []string) (string, error) {
+	ceildirs := C.CString(strings.Join(ceiling_dirs, string(C.GIT_PATH_LIST_SEPARATOR)))
+	defer C.free(unsafe.Pointer(ceildirs))
+
+	cstart := C.CString(start)
+	defer C.free(unsafe.Pointer(cstart))
+
+	retpath := (*C.char)(C.malloc(C.GIT_PATH_MAX))
+	defer C.free(unsafe.Pointer(retpath))
+
+	r := C.git_repository_discover(retpath, C.GIT_PATH_MAX, cstart, cbool(across_fs), ceildirs)
+
+	if r == 0 {
+		return C.GoString(retpath), nil
+	}
+
+	return "", LastError()
+}