/
hash.go
90 lines (81 loc) · 2.51 KB
/
hash.go
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// RAINBOND, Application Management Platform
// Copyright (C) 2014-2017 Goodrain Co., Ltd.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version. For any non-GPL usage of Rainbond,
// one or multiple Commercial Licenses authorized by Goodrain Co., Ltd.
// must be obtained first.
// 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 General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package util
import (
"crypto/md5"
"fmt"
"io"
"math"
"os"
)
const filechunk = 8192 // we settle for 8KB
//CreateFileHash compute sourcefile hash and write hashfile
func CreateFileHash(sourceFile, hashfile string) error {
file, err := os.Open(sourceFile)
if err != nil {
return err
}
defer file.Close()
fileinfo, _ := file.Stat()
if fileinfo.IsDir() {
return fmt.Errorf("do not support compute folder hash")
}
writehashfile, err := os.OpenFile(hashfile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0655)
if err != nil {
return fmt.Errorf("create hash file error %s", err.Error())
}
defer writehashfile.Close()
if fileinfo.Size() < filechunk {
return createSmallFileHash(file, writehashfile)
}
return createBigFileHash(file, writehashfile)
}
func createBigFileHash(sourceFile, hashfile *os.File) error {
// calculate the file size
info, _ := sourceFile.Stat()
filesize := info.Size()
blocks := uint64(math.Ceil(float64(filesize) / float64(filechunk)))
hash := md5.New()
for i := uint64(0); i < blocks; i++ {
blocksize := int(math.Min(filechunk, float64(filesize-int64(i*filechunk))))
buf := make([]byte, blocksize)
index, err := sourceFile.Read(buf)
if err != nil {
return err
}
// append into the hash
_, err = hash.Write(buf[:index])
if err != nil {
return err
}
}
_, err := hashfile.Write([]byte(fmt.Sprintf("%x", hash.Sum(nil))))
if err != nil {
return err
}
return nil
}
func createSmallFileHash(sourceFile, hashfile *os.File) error {
md5h := md5.New()
_, err := io.Copy(md5h, sourceFile)
if err != nil {
return err
}
_, err = hashfile.Write([]byte(fmt.Sprintf("%x", md5h.Sum(nil))))
if err != nil {
return err
}
return nil
}