make it possible to handle errors

1 files changed, 93 insertions, 16 deletions

diff --git a/git.go b/git.go
index 8159244..d6b7dc0 100644
--- a/git.go
+++ b/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 {