forgejo/modules/git/object_format.go

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// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package git
import (
"crypto/sha1"
"fmt"
"regexp"
"strings"
)
type ObjectFormatID int
const (
Sha1 ObjectFormatID = iota
)
// sha1Pattern can be used to determine if a string is an valid sha
var sha1Pattern = regexp.MustCompile(`^[0-9a-f]{4,40}$`)
type ObjectFormat interface {
ID() ObjectFormatID
String() string
// Empty is the hash of empty git
Empty() ObjectID
// EmptyTree is the hash of an empty tree
EmptyTree() ObjectID
// FullLength is the length of the hash's hex string
FullLength() int
IsValid(input string) bool
MustID(b []byte) ObjectID
MustIDFromString(s string) ObjectID
NewID(b []byte) (ObjectID, error)
NewIDFromString(s string) (ObjectID, error)
NewEmptyID() ObjectID
NewHasher() HasherInterface
}
type Sha1ObjectFormat struct{}
func (*Sha1ObjectFormat) ID() ObjectFormatID { return Sha1 }
func (*Sha1ObjectFormat) String() string { return "sha1" }
func (*Sha1ObjectFormat) Empty() ObjectID { return &Sha1Hash{} }
func (*Sha1ObjectFormat) EmptyTree() ObjectID {
return &Sha1Hash{
0x4b, 0x82, 0x5d, 0xc6, 0x42, 0xcb, 0x6e, 0xb9, 0xa0, 0x60,
0xe5, 0x4b, 0xf8, 0xd6, 0x92, 0x88, 0xfb, 0xee, 0x49, 0x04,
}
}
func (*Sha1ObjectFormat) FullLength() int { return 40 }
func (*Sha1ObjectFormat) IsValid(input string) bool {
return sha1Pattern.MatchString(input)
}
func (*Sha1ObjectFormat) MustID(b []byte) ObjectID {
var id Sha1Hash
copy(id[0:20], b)
return &id
}
func (h *Sha1ObjectFormat) MustIDFromString(s string) ObjectID {
return MustIDFromString(h, s)
}
func (h *Sha1ObjectFormat) NewID(b []byte) (ObjectID, error) {
return IDFromRaw(h, b)
}
func (h *Sha1ObjectFormat) NewIDFromString(s string) (ObjectID, error) {
return genericIDFromString(h, s)
}
func (*Sha1ObjectFormat) NewEmptyID() ObjectID {
return NewSha1()
}
func (h *Sha1ObjectFormat) NewHasher() HasherInterface {
return &Sha1Hasher{sha1.New()}
}
func ObjectFormatFromID(id ObjectFormatID) ObjectFormat {
switch id {
case Sha1:
return &Sha1ObjectFormat{}
}
return nil
}
func ObjectFormatFromString(hash string) (ObjectFormat, error) {
switch strings.ToLower(hash) {
case "sha1":
return &Sha1ObjectFormat{}, nil
}
return nil, fmt.Errorf("unknown hash type: %s", hash)
}