package plumbing import ( "bytes" "encoding/hex" "sort" "strconv" "github.com/go-git/go-git/v5/plumbing/hash" ) // Hash SHA1 hashed content type Hash [hash.Size]byte // ZeroHash is Hash with value zero var ZeroHash Hash // ComputeHash compute the hash for a given ObjectType and content func ComputeHash(t ObjectType, content []byte) Hash { h := NewHasher(t, int64(len(content))) h.Write(content) return h.Sum() } // NewHash return a new Hash from a hexadecimal hash representation func NewHash(s string) Hash { b, _ := hex.DecodeString(s) var h Hash copy(h[:], b) return h } func (h Hash) IsZero() bool { var empty Hash return h == empty } func (h Hash) String() string { return hex.EncodeToString(h[:]) } type Hasher struct { hash.Hash } func NewHasher(t ObjectType, size int64) Hasher { h := Hasher{hash.New(hash.CryptoType)} h.Write(t.Bytes()) h.Write([]byte(" ")) h.Write([]byte(strconv.FormatInt(size, 10))) h.Write([]byte{0}) return h } func (h Hasher) Sum() (hash Hash) { copy(hash[:], h.Hash.Sum(nil)) return } // HashesSort sorts a slice of Hashes in increasing order. func HashesSort(a []Hash) { sort.Sort(HashSlice(a)) } // HashSlice attaches the methods of sort.Interface to []Hash, sorting in // increasing order. type HashSlice []Hash func (p HashSlice) Len() int { return len(p) } func (p HashSlice) Less(i, j int) bool { return bytes.Compare(p[i][:], p[j][:]) < 0 } func (p HashSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] } // IsHash returns true if the given string is a valid hash. func IsHash(s string) bool { switch len(s) { case hash.HexSize: _, err := hex.DecodeString(s) return err == nil default: return false } }