make it possible to handle errors

git.go

@@ -15,14 +15,66 @@ import (
 	"unsafe"
 )
 
+type ErrorClass int
+
 const (
-	ITEROVER  = C.GIT_ITEROVER
-	EEXISTS   = C.GIT_EEXISTS
-	ENOTFOUND = C.GIT_ENOTFOUND
+	ErrClassNone       ErrorClass = C.GITERR_NONE
+	ErrClassNoMemory              = C.GITERR_NOMEMORY
+	ErrClassOs                    = C.GITERR_OS
+	ErrClassInvalid               = C.GITERR_INVALID
+	ErrClassReference             = C.GITERR_REFERENCE
+	ErrClassZlib                  = C.GITERR_ZLIB
+	ErrClassRepository            = C.GITERR_REPOSITORY
+	ErrClassConfig                = C.GITERR_CONFIG
+	ErrClassRegex                 = C.GITERR_REGEX
+	ErrClassOdb                   = C.GITERR_ODB
+	ErrClassIndex                 = C.GITERR_INDEX
+	ErrClassObject                = C.GITERR_OBJECT
+	ErrClassNet                   = C.GITERR_NET
+	ErrClassTag                   = C.GITERR_TAG
+	ErrClassTree                  = C.GITERR_TREE
+	ErrClassIndexer               = C.GITERR_INDEXER
+	ErrClassSSL                   = C.GITERR_SSL
+	ErrClassSubmodule             = C.GITERR_SUBMODULE
+	ErrClassThread                = C.GITERR_THREAD
+	ErrClassStash                 = C.GITERR_STASH
+	ErrClassCheckout              = C.GITERR_CHECKOUT
+	ErrClassFetchHead             = C.GITERR_FETCHHEAD
+	ErrClassMerge                 = C.GITERR_MERGE
+	ErrClassSsh                   = C.GITERR_SSH
+	ErrClassFilter                = C.GITERR_FILTER
+	ErrClassRevert                = C.GITERR_REVERT
+	ErrClassCallback              = C.GITERR_CALLBACK
 )
 
-var (
-	ErrIterOver = errors.New("Iteration is over")
+type ErrorCode int
+
+const (
+	ErrOk ErrorCode = C.GIT_OK /*< No error */
+
+	ErrGeneric   = C.GIT_ERROR      /*< Generic error */
+	ErrNotFound  = C.GIT_ENOTFOUND  /*< Requested object could not be found */
+	ErrExists    = C.GIT_EEXISTS    /*< Object exists preventing operation */
+	ErrAmbigious = C.GIT_EAMBIGUOUS /*< More than one object matches */
+	ErrBuffs     = C.GIT_EBUFS      /*< Output buffer too short to hold data */
+
+	/* GIT_EUSER is a special error that is never generated by libgit2
+	 * code.  You can return it from a callback (e.g to stop an iteration)
+	 * to know that it was generated by the callback and not by libgit2.
+	 */
+	ErrUser = C.GIT_EUSER
+
+	ErrBareRepo       = C.GIT_EBAREREPO       /*< Operation not allowed on bare repository */
+	ErrUnbornBranch   = C.GIT_EUNBORNBRANCH   /*< HEAD refers to branch with no commits */
+	ErrUnmerged       = C.GIT_EUNMERGED       /*< Merge in progress prevented operation */
+	ErrNonFastForward = C.GIT_ENONFASTFORWARD /*< Reference was not fast-forwardable */
+	ErrInvalidSpec    = C.GIT_EINVALIDSPEC    /*< Name/ref spec was not in a valid format */
+	ErrMergeConflict  = C.GIT_EMERGECONFLICT  /*< Merge conflicts prevented operation */
+	ErrLocked         = C.GIT_ELOCKED         /*< Lock file prevented operation */
+	ErrModified       = C.GIT_EMODIFIED       /*< Reference value does not match expected */
+
+	ErrPassthrough = C.GIT_PASSTHROUGH /*< Internal only */
+	ErrIterOver    = C.GIT_ITEROVER    /*< Signals end of iteration with iterator */
 )
 
 func init() {
@@ -64,6 +116,10 @@ func NewOid(s string) (*Oid, error) {
 		return nil, error
 	}
 
+	if len(slice) != 20 {
+		return nil, &GitError{"Invalid Oid", ErrClassNone, ErrGeneric}
+	}
+
 	copy(o[:], slice[:20])
 	return o, nil
 }
@@ -124,29 +180,50 @@ func ShortenOids(ids []*Oid, minlen int) (int, error) {
 }
 
 type GitError struct {
-	Message   string
-	Class     int
-	ErrorCode int
+	Message string
+	Class   ErrorClass
+	Code    ErrorCode
 }
 
 func (e GitError) Error() string {
 	return e.Message
 }
 
-func IsNotExist(err error) bool {
-	return err.(*GitError).ErrorCode == C.GIT_ENOTFOUND
+func IsErrorClass(err error, c ErrorClass) bool {
+
+	if err == nil {
+		return false
+	}
+	if gitError, ok := err.(*GitError); ok {
+		return gitError.Class == c
+	}
+	return false
 }
 
-func IsExist(err error) bool {
-	return err.(*GitError).ErrorCode == C.GIT_EEXISTS
+func IsErrorCode(err error, c ErrorCode) bool {
+	if err == nil {
+		return false
+	}
+	if gitError, ok := err.(*GitError); ok {
+		return gitError.Code == c
+	}
+	return false
 }
 
 func MakeGitError(errorCode C.int) error {
-	err := C.giterr_last()
-	if err == nil {
-		return &GitError{"No message", C.GITERR_INVALID, C.GIT_ERROR}
+
+	var errMessage string
+	var errClass ErrorClass
+	if errorCode != ErrIterOver {
+		err := C.giterr_last()
+		if err != nil {
+			errMessage = C.GoString(err.message)
+			errClass = ErrorClass(err.klass)
+		} else {
+			errClass = ErrClassInvalid
+		}
 	}
-	return &GitError{C.GoString(err.message), int(err.klass), int(errorCode)}
+	return &GitError{errMessage, errClass, ErrorCode(errorCode)}
 }
 
 func MakeGitError2(err int) error {

git_test.go

@@ -62,3 +62,10 @@ func TestOidZero(t *testing.T) {
 		t.Error("Zero Oid is not zero")
 	}
 }
+
+func TestEmptyOid(t *testing.T) {
+	_, err := NewOid("")
+	if err == nil || !IsErrorCode(err, ErrGeneric) {
+		t.Fatal("Should have returned invalid error")
+	}
+}

index.go

@@ -266,10 +266,6 @@ func (v *IndexConflictIterator) Next() (IndexConflict, error) {
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_index_conflict_next(&cancestor, &cour, &ctheir, v.ptr)
-	if ecode == C.GIT_ITEROVER {
-		return IndexConflict{}, ErrIterOver
-	}
-
 	if ecode < 0 {
 		return IndexConflict{}, MakeGitError(ecode)
 	}

push_test.go

@@ -1,7 +1,6 @@
 package git
 
 import (
-	"log"
 	"os"
 	"testing"
 	"time"
@@ -45,7 +44,6 @@ func Test_Push_ToRemote(t *testing.T) {
 	checkFatal(t, err)
 
 	err = push.StatusForeach(func(ref string, msg string) int {
-		log.Printf("%s -> %s", ref, msg)
 		return 0
 	})
 	checkFatal(t, err)

reference.go

@@ -237,9 +237,6 @@ func (v *ReferenceIterator) NextName() (string, error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_reference_next_name(&ptr, v.ptr)
-	if ret == ITEROVER {
-		return "", ErrIterOver
-	}
 	if ret < 0 {
 		return "", MakeGitError(ret)
 	}
@@ -269,9 +266,6 @@ func (v *ReferenceIterator) NameIter() <-chan string {
 func (v *ReferenceIterator) Next() (*Reference, error) {
 	var ptr *C.git_reference
 	ret := C.git_reference_next(&ptr, v.ptr)
-	if ret == ITEROVER {
-		return nil, ErrIterOver
-	}
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}

reference_test.go

@@ -111,7 +111,7 @@ func TestIterator(t *testing.T) {
 		list = append(list, name)
 		name, err = iter.NextName()
 	}
-	if err != ErrIterOver {
+	if !IsErrorCode(err, ErrIterOver) {
 		t.Fatal("Iteration not over")
 	}
 
@@ -127,7 +127,7 @@ func TestIterator(t *testing.T) {
 		count++
 		_, err = iter.Next()
 	}
-	if err != ErrIterOver {
+	if !IsErrorCode(err, ErrIterOver) {
 		t.Fatal("Iteration not over")
 	}
 

walk.go

@@ -7,7 +7,6 @@ package git
 import "C"
 
 import (
-	"io"
 	"runtime"
 	"unsafe"
 )
@@ -158,8 +157,6 @@ func (v *RevWalk) Next(id *Oid) (err error) {
 
 	ret := C.git_revwalk_next(id.toC(), v.ptr)
 	switch {
-	case ret == ITEROVER:
-		err = io.EOF
 	case ret < 0:
 		err = MakeGitError(ret)
 	}
@@ -173,7 +170,7 @@ func (v *RevWalk) Iterate(fun RevWalkIterator) (err error) {
 	oid := new(Oid)
 	for {
 		err = v.Next(oid)
-		if err == io.EOF {
+		if IsErrorCode(err, ErrIterOver) {
 			return nil
 		}
 		if err != nil {