90 lines
2.2 KiB
Go
90 lines
2.2 KiB
Go
// SiYuan - Refactor your thinking
|
|
// Copyright (c) 2020-present, b3log.org
|
|
//
|
|
// This program is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Affero General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// This program is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU Affero General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Affero General Public License
|
|
// along with this program. If not, see <https://www.gnu.org/licenses/>.
|
|
|
|
package util
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/sha1"
|
|
"encoding/base64"
|
|
"io"
|
|
"os"
|
|
|
|
"github.com/siyuan-note/filelock"
|
|
)
|
|
|
|
// 以下是七牛云 Hash 算法实现 https://github.com/qiniu/qetag/blob/master/qetag.go
|
|
|
|
func GetEtagByHandle(f io.Reader, size int64) (etag string, err error) {
|
|
blockCnt := BlockCount(size)
|
|
sha1Buf := make([]byte, 0, 21)
|
|
|
|
if blockCnt <= 1 { // file size <= 4M
|
|
sha1Buf = append(sha1Buf, 0x16)
|
|
sha1Buf, err = CalSha1(sha1Buf, f)
|
|
if err != nil {
|
|
return
|
|
}
|
|
} else { // file size > 4M
|
|
sha1Buf = append(sha1Buf, 0x96)
|
|
sha1BlockBuf := make([]byte, 0, blockCnt*20)
|
|
for i := 0; i < blockCnt; i++ {
|
|
body := io.LimitReader(f, BLOCK_SIZE)
|
|
sha1BlockBuf, err = CalSha1(sha1BlockBuf, body)
|
|
if err != nil {
|
|
return
|
|
}
|
|
}
|
|
sha1Buf, _ = CalSha1(sha1Buf, bytes.NewReader(sha1BlockBuf))
|
|
}
|
|
etag = base64.URLEncoding.EncodeToString(sha1Buf)
|
|
return
|
|
}
|
|
|
|
func GetEtag(filename string) (etag string, err error) {
|
|
f, err := filelock.OpenFile(filename, os.O_RDONLY, 0644)
|
|
if err != nil {
|
|
return
|
|
}
|
|
defer filelock.CloseFile(f)
|
|
|
|
fi, err := f.Stat()
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
etag, err = GetEtagByHandle(f, fi.Size())
|
|
return
|
|
}
|
|
|
|
const (
|
|
BLOCK_BITS = 22 // Indicate that the blocksize is 4M
|
|
BLOCK_SIZE = 1 << BLOCK_BITS
|
|
)
|
|
|
|
func BlockCount(fsize int64) int {
|
|
return int((fsize + (BLOCK_SIZE - 1)) >> BLOCK_BITS)
|
|
}
|
|
|
|
func CalSha1(b []byte, r io.Reader) ([]byte, error) {
|
|
|
|
h := sha1.New()
|
|
_, err := io.Copy(h, r)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return h.Sum(b), nil
|
|
}
|