mirror of
https://codeberg.org/forgejo/forgejo
synced 2024-11-24 02:36:10 +01:00
cbf923e87b
Refactor Hash interfaces and centralize hash function. This will allow easier introduction of different hash function later on. This forms the "no-op" part of the SHA256 enablement patch.
144 lines
2.9 KiB
Go
144 lines
2.9 KiB
Go
// Copyright 2023 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package git
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import (
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"bytes"
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"encoding/hex"
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"errors"
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"fmt"
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"hash"
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"strconv"
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"strings"
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)
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type ObjectID interface {
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String() string
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IsZero() bool
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RawValue() []byte
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Type() ObjectFormat
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}
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/* SHA1 */
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type Sha1Hash [20]byte
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func (h *Sha1Hash) String() string {
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return hex.EncodeToString(h[:])
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}
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func (h *Sha1Hash) IsZero() bool {
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empty := Sha1Hash{}
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return bytes.Equal(empty[:], h[:])
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}
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func (h *Sha1Hash) RawValue() []byte { return h[:] }
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func (*Sha1Hash) Type() ObjectFormat { return &Sha1ObjectFormat{} }
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func NewSha1() *Sha1Hash {
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return &Sha1Hash{}
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}
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// generic implementations
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func NewHash(hash string) (ObjectID, error) {
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hash = strings.ToLower(hash)
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switch hash {
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case "sha1":
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return &Sha1Hash{}, nil
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}
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return nil, errors.New("unsupported hash type")
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}
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func IDFromRaw(h ObjectFormat, b []byte) (ObjectID, error) {
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if len(b) != h.FullLength()/2 {
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return h.Empty(), fmt.Errorf("length must be %d: %v", h.FullLength(), b)
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}
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return h.MustID(b), nil
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}
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func MustIDFromString(h ObjectFormat, s string) ObjectID {
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b, _ := hex.DecodeString(s)
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return h.MustID(b)
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}
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func genericIDFromString(h ObjectFormat, s string) (ObjectID, error) {
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s = strings.TrimSpace(s)
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if len(s) != h.FullLength() {
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return h.Empty(), fmt.Errorf("length must be %d: %s", h.FullLength(), s)
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}
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b, err := hex.DecodeString(s)
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if err != nil {
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return h.Empty(), err
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}
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return h.NewID(b)
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}
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// utils
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func IDFromString(hexHash string) (ObjectID, error) {
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switch len(hexHash) {
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case 40:
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hashType := Sha1ObjectFormat{}
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h, err := hashType.NewIDFromString(hexHash)
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if err != nil {
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return nil, err
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}
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return h, nil
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}
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return nil, fmt.Errorf("invalid hash hex string: '%s' len: %d", hexHash, len(hexHash))
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}
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func IsEmptyCommitID(commitID string) bool {
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if commitID == "" {
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return true
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}
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id, err := IDFromString(commitID)
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if err != nil {
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return false
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}
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return id.IsZero()
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}
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// HashInterface is a struct that will generate a Hash
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type HasherInterface interface {
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hash.Hash
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HashSum() ObjectID
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}
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type Sha1Hasher struct {
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hash.Hash
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}
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// ComputeBlobHash compute the hash for a given blob content
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func ComputeBlobHash(hashType ObjectFormat, content []byte) ObjectID {
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return ComputeHash(hashType, ObjectBlob, content)
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}
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// ComputeHash compute the hash for a given ObjectType and content
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func ComputeHash(hashType ObjectFormat, t ObjectType, content []byte) ObjectID {
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h := hashType.NewHasher()
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_, _ = h.Write(t.Bytes())
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_, _ = h.Write([]byte(" "))
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_, _ = h.Write([]byte(strconv.FormatInt(int64(len(content)), 10)))
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_, _ = h.Write([]byte{0})
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return h.HashSum()
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}
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// Sum generates a SHA1 for the provided hash
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func (h *Sha1Hasher) HashSum() ObjectID {
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var sha1 Sha1Hash
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copy(sha1[:], h.Hash.Sum(nil))
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return &sha1
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}
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type ErrInvalidSHA struct {
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SHA string
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}
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func (err ErrInvalidSHA) Error() string {
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return fmt.Sprintf("invalid sha: %s", err.SHA)
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}
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