/
hashobject.go
65 lines (58 loc) · 1.37 KB
/
hashobject.go
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package git
import (
"bytes"
"crypto/sha1"
"fmt"
"io"
"io/ioutil"
"os"
"strings"
)
func HashReaderWithSize(t string, sz int64, r io.Reader) (Sha1, error) {
h := sha1.New()
fmt.Fprintf(h, "%s %d\000", t, sz)
if sz < 0 {
return Sha1{}, fmt.Errorf("Invalid size: %v", sz)
}
n, err := io.Copy(h, r)
if err != nil {
return Sha1{}, err
}
if n != sz {
return Sha1{}, fmt.Errorf("Unexpected reader size (got %v != want %v)", n, sz)
}
return Sha1FromSlice(h.Sum(nil))
}
// Hashes the data of r with object type t, and returns
// the hash, and the data that was read from r.
func HashReader(t string, r io.Reader) (Sha1, []byte, error) {
// Need to read the whole reader in order to find the size
data, err := ioutil.ReadAll(r)
if err != nil {
return Sha1{}, nil, err
}
h := sha1.New()
fmt.Fprintf(h, "%s %d\000%s", t, len(data), data)
s, err := Sha1FromSlice(h.Sum(nil))
return s, data, err
}
func HashSlice(t string, data []byte) (Sha1, []byte, error) {
r := bytes.NewReader(data)
return HashReader(t, r)
}
func HashFile(t, filename string) (Sha1, []byte, error) {
if File(filename).IsSymlink() {
l, err := os.Readlink(filename)
if err != nil {
return Sha1{}, nil, err
}
return HashReader(t, strings.NewReader(l))
} else {
r, err := os.Open(filename)
if err != nil {
return Sha1{}, nil, err
}
defer r.Close()
return HashReader(t, r)
}
}