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gitea/modules/git/sha1.go

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Go

// Copyright 2015 The Gogs Authors. All rights reserved.
// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package git
import (
"encoding/hex"
"fmt"
"regexp"
"strings"
)
// EmptySHA defines empty git SHA (undefined, non-existent)
const EmptySHA = "0000000000000000000000000000000000000000"
// EmptyTreeSHA is the SHA of an empty tree, the root of all git repositories
const EmptyTreeSHA = "4b825dc642cb6eb9a060e54bf8d69288fbee4904"
// SHAFullLength is the full length of a git SHA
const SHAFullLength = 40
// SHAPattern can be used to determine if a string is an valid sha
var shaPattern = regexp.MustCompile(`^[0-9a-f]{4,40}$`)
// IsValidSHAPattern will check if the provided string matches the SHA Pattern
func IsValidSHAPattern(sha string) bool {
return shaPattern.MatchString(sha)
}
type ErrInvalidSHA struct {
SHA string
}
func (err ErrInvalidSHA) Error() string {
return fmt.Sprintf("invalid sha: %s", err.SHA)
}
// MustID always creates a new SHA1 from a [20]byte array with no validation of input.
func MustID(b []byte) SHA1 {
var id SHA1
copy(id[:], b)
return id
}
// NewID creates a new SHA1 from a [20]byte array.
func NewID(b []byte) (SHA1, error) {
if len(b) != 20 {
return SHA1{}, fmt.Errorf("Length must be 20: %v", b)
}
return MustID(b), nil
}
// MustIDFromString always creates a new sha from a ID with no validation of input.
func MustIDFromString(s string) SHA1 {
b, _ := hex.DecodeString(s)
return MustID(b)
}
// NewIDFromString creates a new SHA1 from a ID string of length 40.
func NewIDFromString(s string) (SHA1, error) {
var id SHA1
s = strings.TrimSpace(s)
if len(s) != SHAFullLength {
return id, fmt.Errorf("Length must be 40: %s", s)
}
b, err := hex.DecodeString(s)
if err != nil {
return id, err
}
return NewID(b)
}