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gitea-fork-majority-judgment/modules/lfs/content_store.go

95 lines
2.0 KiB

package lfs
import (
"code.gitea.io/gitea/models"
"crypto/sha256"
"encoding/hex"
"errors"
"io"
"os"
"path/filepath"
)
var (
errHashMismatch = errors.New("Content hash does not match OID")
errSizeMismatch = errors.New("Content size does not match")
)
// ContentStore provides a simple file system based storage.
type ContentStore struct {
BasePath string
}
// Get takes a Meta object and retrieves the content from the store, returning
// it as an io.Reader. If fromByte > 0, the reader starts from that byte
func (s *ContentStore) Get(meta *models.LFSMetaObject, fromByte int64) (io.ReadCloser, error) {
path := filepath.Join(s.BasePath, transformKey(meta.Oid))
f, err := os.Open(path)
if err != nil {
return nil, err
}
if fromByte > 0 {
_, err = f.Seek(fromByte, os.SEEK_CUR)
}
return f, err
}
// Put takes a Meta object and an io.Reader and writes the content to the store.
func (s *ContentStore) Put(meta *models.LFSMetaObject, r io.Reader) error {
path := filepath.Join(s.BasePath, transformKey(meta.Oid))
tmpPath := path + ".tmp"
dir := filepath.Dir(path)
if err := os.MkdirAll(dir, 0750); err != nil {
return err
}
file, err := os.OpenFile(tmpPath, os.O_CREATE|os.O_WRONLY|os.O_EXCL, 0640)
if err != nil {
return err
}
defer os.Remove(tmpPath)
hash := sha256.New()
hw := io.MultiWriter(hash, file)
written, err := io.Copy(hw, r)
if err != nil {
file.Close()
return err
}
file.Close()
if written != meta.Size {
return errSizeMismatch
}
shaStr := hex.EncodeToString(hash.Sum(nil))
if shaStr != meta.Oid {
return errHashMismatch
}
if err := os.Rename(tmpPath, path); err != nil {
return err
}
return nil
}
// Exists returns true if the object exists in the content store.
func (s *ContentStore) Exists(meta *models.LFSMetaObject) bool {
path := filepath.Join(s.BasePath, transformKey(meta.Oid))
if _, err := os.Stat(path); os.IsNotExist(err) {
return false
}
return true
}
func transformKey(key string) string {
if len(key) < 5 {
return key
}
return filepath.Join(key[0:2], key[2:4], key[4:])
}