forked from shazow/go-git
/
blob.go
134 lines (112 loc) · 2.67 KB
/
blob.go
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package git
import (
"bytes"
"compress/zlib"
"crypto"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
)
type Blob struct {
*TreeEntry
}
func (b *Blob) Data() ([]byte, error) {
o, err := b.ptree.repo.object(b.Id, false)
if err != nil {
return nil, err
}
return o.Data, nil
}
// Write `r` in git's compressed object format into `w`.
func copyCompressed(w io.Writer, r io.Reader) error {
cw, err := zlib.NewWriterLevel(w, zlib.BestSpeed)
if err != nil {
return err
}
_, err = io.Copy(cw, r)
if err != nil {
return err
}
err = cw.Close()
if err != nil {
return err
}
return nil
}
// Add '<type> <size>\x00' to beginning of `r`.
func PrependObjectHeader(objectType ObjectType, r io.ReadSeeker) (io.Reader, error) {
size, err := r.Seek(0, os.SEEK_END)
if err != nil {
return nil, err
}
_, err = r.Seek(0, os.SEEK_SET)
if err != nil {
return nil, err
}
buf := bytes.NewBufferString(fmt.Sprintf("%s %d\x00", objectType, size))
return io.MultiReader(buf, r), nil
}
// Write an the object contents in `r` in compressed form to `w` and return the
// hash.
// Special case: if `w` is `ioutil.Discard`, the data is not compressed,
// since the data is not consumed anywhere.
func StoreObjectSHA(
objectType ObjectType,
w io.Writer,
r io.ReadSeeker,
) (ObjectID, error) {
reader, err := PrependObjectHeader(objectType, r)
if err != nil {
return "", err
}
hash := crypto.SHA1.New()
reader = io.TeeReader(reader, hash)
if w == ioutil.Discard {
_, err = io.Copy(w, r)
} else {
err = copyCompressed(w, reader)
}
if err != nil {
return "", err
}
return ObjectID(hash.Sum(nil)), nil
}
// Write an object into git's loose database.
// If the object already exists in the database, it is not overwritten, though
// the compression is still performed.
func (repo *Repository) StoreObjectLoose(
objectType ObjectType,
r io.ReadSeeker,
) (ObjectID, error) {
fd, err := ioutil.TempFile(filepath.Join(repo.Path, "objects"), ".gogit_")
if err != nil {
return "", fmt.Errorf("failed to make tmpfile: %v", err)
}
id, err := StoreObjectSHA(objectType, fd, r)
if err != nil {
fd.Close()
return "", err
}
fd.Close() // Not deferred, intentionally.
objectPath := filepathFromSHA1(repo.Path, id.String())
if _, err = os.Stat(objectPath); err == nil {
// Object already exists. Delete the temporary file.
err = os.Remove(fd.Name())
if err != nil {
return "", err
}
return id, nil
}
err = os.Mkdir(filepath.Dir(objectPath), 0775)
if err != nil && !os.IsExist(err) {
// Failed to create the directory, and not because it already exists.
return "", err
}
err = os.Rename(fd.Name(), objectPath)
if err != nil {
return "", err
}
return id, nil
}