114 lines
2.6 KiB
Go
114 lines
2.6 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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"fmt"
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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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var _ ObjectID = &Sha1Hash{}
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func MustIDFromString(hexHash string) ObjectID {
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id, err := NewIDFromString(hexHash)
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if err != nil {
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panic(err)
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}
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return id
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}
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/* SHA256 */
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type Sha256Hash [32]byte
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func (h *Sha256Hash) String() string {
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return hex.EncodeToString(h[:])
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}
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func (h *Sha256Hash) IsZero() bool {
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empty := Sha256Hash{}
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return bytes.Equal(empty[:], h[:])
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}
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func (h *Sha256Hash) RawValue() []byte { return h[:] }
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func (*Sha256Hash) Type() ObjectFormat { return Sha256ObjectFormat }
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/* utility */
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func NewIDFromString(hexHash string) (ObjectID, error) {
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var theObjectFormat ObjectFormat
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for _, objectFormat := range SupportedObjectFormats {
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if len(hexHash) == objectFormat.FullLength() {
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theObjectFormat = objectFormat
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break
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}
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}
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if theObjectFormat == nil {
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return nil, fmt.Errorf("length %d has no matched object format: %s", len(hexHash), hexHash)
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}
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b, err := hex.DecodeString(hexHash)
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if err != nil {
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return nil, err
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}
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if len(b) != theObjectFormat.FullLength()/2 {
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return theObjectFormat.EmptyObjectID(), fmt.Errorf("length must be %d: %v", theObjectFormat.FullLength(), b)
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}
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return theObjectFormat.MustID(b), nil
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}
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// IsEmptyCommitID checks if an hexadecimal string represents an empty commit according to git (only '0').
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// If objectFormat is not nil, the length will be checked as well (otherwise the lenght must match the sha1 or sha256 length).
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func IsEmptyCommitID(commitID string, objectFormat ObjectFormat) bool {
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if commitID == "" {
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return true
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}
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if objectFormat == nil {
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if Sha1ObjectFormat.FullLength() != len(commitID) && Sha256ObjectFormat.FullLength() != len(commitID) {
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return false
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}
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} else if objectFormat.FullLength() != len(commitID) {
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return false
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}
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for _, c := range commitID {
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if c != '0' {
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return false
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}
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}
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return true
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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 hashType.ComputeHash(ObjectBlob, content)
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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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