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// Copyright 2015 The Gogs Authors. All rights reserved.
// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
//go:build !gogit
package git
import (
"crypto/sha1"
"encoding/hex"
"hash"
"strconv"
)
// SHA1 a git commit name
type SHA1 [20]byte
// String returns a string representation of the SHA
func (s SHA1) String() string {
return hex.EncodeToString(s[:])
}
// IsZero returns whether this SHA1 is all zeroes
func (s SHA1) IsZero() bool {
var empty SHA1
return s == empty
}
// ComputeBlobHash compute the hash for a given blob content
func ComputeBlobHash(content []byte) SHA1 {
return ComputeHash(ObjectBlob, content)
}
// ComputeHash compute the hash for a given ObjectType and content
func ComputeHash(t ObjectType, content []byte) SHA1 {
h := NewHasher(t, int64(len(content)))
_, _ = h.Write(content)
return h.Sum()
}
// Hasher is a struct that will generate a SHA1
type Hasher struct {
hash.Hash
}
// NewHasher takes an object type and size and creates a hasher to generate a SHA
func NewHasher(t ObjectType, size int64) Hasher {
h := Hasher{sha1.New()}
_, _ = h.Write(t.Bytes())
_, _ = h.Write([]byte(" "))
_, _ = h.Write([]byte(strconv.FormatInt(size, 10)))
_, _ = h.Write([]byte{0})
return h
}
// Sum generates a SHA1 for the provided hash
func (h Hasher) Sum() (sha1 SHA1) {
copy(sha1[:], h.Hash.Sum(nil))
return sha1
}
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